WO2015076780A1 - A vented rigid gas sterilization packaging tray - Google Patents

Abstract

A vented rigid tray for gas sterilization having (a) a synthetic polymer tray wa!i with exterior and interior surfaces, a base and upstanding sidewall, with a foraminous wall portion in the base and/or sidewall; (b) filter media; (c) a foraminous cap; and (d) snap fit attachment means for the foraminous cap and tray wall where the filter media is held between the cap and foraminous wall portion.

Description

Attorney Docket No. 20808- WO

A VENTED RIGID GAS STERILIZATION PACKAGING TRAY

BACKGROUND

1. Technical Field

[00013 The present application relates generally to gas sterilization packaging trays and more specifically to venting and filtration means for such trays.

2, Background Information

[0002] There are many types of sterilization containers which serve various needs. One class of containers are known as hospital sterilization containers and are used to sterilize articles of various shapes and sizes just prior to or within hours or a few days of their intended use. They are usually reusable rigid containers adapted for sterilization typically by steam under pressure e.g. in an autoclave, and are often used with equipment which is re-usable and not disposable. These hospital sterilization

containers are typically loaded and sterilized at the hospital. They are not designed for a particular single product and they are not intended for shipping or to provide long term sterility. They do not typically require heat sealing equipment for closure, but are commonly designed to be mechanically closed by hand. Examples of hospital sterilization containers are One Tray® Sealed Containers from Sterile Containment Technology, LLC of Richmond, California, USA and SteriTite® containers from Case Medical Inc. of Ridgefieid, New Jersey, USA. Hospital sterilization containers are also disclosed e.g. in U.S. Patent Nos. 5,968,459 (Naiepa et ai); 6,319,481 (Banks et al); 6,468,482 (Frieze et al); 6,589,477 (Frieze et al); 7,595,032 (Banks et al); 8,418,872 (Smith); and U.S. Patent Application Publication No. 2010/0154353 (Cesa et al).

[0003] Another class of sterilization containers is known as medical package sterilization coniainers and is designed for sterilization prior to delivery to a hospital or surgical facility. This class of containers is designed for single use and to withstand shipping and distribution. The containers are typically employed by article Attorney Docket No. 20808- WO manufacturers to package disposable or impiantable articles, which are sterilized by the article manufacturer or at a special sterilization service facility usually sterilizing many packages at once which have been loaded into bulk containers. Medicai package sterilization containers typically require heat sealing equipment for closure and often use ethylene oxide gas as the steriiant These medical packaging sterilization containers typically are used to provide many months or years of sterile she!f life for their contents. 00043 The present invention relates to medical packaging sterilization containers which may be used by article manufacturers to provide long term sterility of articles which are designed for shipment and storage without the necessity for being used within hours or a day or so of sterilization. Articles, such as medical devices, can be held within a medical packaging sterilization container e.g. a sealed tray to protect the contents from microbial contamination, airborne particulates, foreign matter, etc, for an extended period of time e.g. months or years. The medical packaging sterilization container may be a rigid polymeric tray having a peelabSe heat sealed lid stock covering the tray top with contents held inside the tray which may also include package inserts to stabilize the artic!e(s) located therein from movement during transport. Typically, disposable medical equipment and implantable devices are sterilized following packaging and before transport to healthcare providers. Common forms of sterilization include irradiation, autoclaving, and treatment with a sterilizing gas, such as ethylene oxide (ETO).

[00053 in order to gas sterilize articles and maintain sterility, certain containers e.g. pouches or trays are provided with a gas permeable membrane, wall or lidding which allows introduction and removal of a sterilizing gas such as ethylene oxide. This gas permeable Sid or wall also functions as a barrier to entry of pathogens such as bacteria, viruses and other microbes. Articles such as medical devices and tools e.g. artificial joints, stents, implantable structures and equipment, surgical knives, catheters, clamps, etc. may be stored and transported in a sterile condition until needed whereupon the contents may be accessed under controlled conditions to minimize infection and Attorney Docket No. 20808- WO introduction of undesirable organisms. These medical packaging steriiization containers often use spunbonded poiyo!efin polymeric sheets such as Tyvek® as a permeable membrane lid or waS! component to permit gas sterilization and to act as a microbial barrier; see e.g. European Patent EP 07850868. Examples of medicai packaging steriiization containers are disclosed in U.S. Patent Nos. 4,022,324 (Schuster);

4,482,053 (Aipern et al); 5,342,673 (Bowman et al); U.S. Patent Application Publication No. 2011/0139650 (Dworak); and PCX Publication No, WO 91/11374 (Gogdiii et al).

[0006] A typical medical device package has a sheet of opaque breathable material sealed to the peripheral: edge of a tray or flexible thermoformed blister container to form a lidding. After placing and sealing an article inside, a sterilizing gas is admitted into the interior of the package through the breathable membrane.

[0007] Existing types of packaging have several disadvantages. In particular, the commonly employed material thermoplastic coated paper or thermoplastic coated Tyveki⁾ spun bonded polyolefin are opaque and prevent inspection of package contents prior to opening. They are also susceptible to weakened seals and failure in gas steriiization due to the use of elevated temperatures and steam. More careful and time consuming handling must be used to minimize seal failures which negatively impacts packaging productivity and limits the speed at which such packages can be

manufactured. Opening of the package for use also raises potential problems. Use of nonwoven sheet material made of individual fibers that are thermally bonded to each other may potentially result in exposure to, or formation during an opening process, of small fibers that may be deposited on the sterilized article; this a particular concern where such nonwoven spunbonded polyolefin sheets are included as a wali component and form a peelable seam. Also, spunbonded nonwovens such as Tyvek® are expensive.

[0008] Accordingly, there is a need for improved packaging, for a transparent package that facilitates inspection of its contents, for a package with improved sealing, and for a more cost and labor efficient method for the packaging and sterilization of Attorney Docket No. 20808- WO catheters, stents, implants, and other medical devices and instruments. It would be desirable to utilize gas sterilization in rigid containers where such containers are preferred or in applications where use of a flexible membrane materia! is undesirable. Furthermore: membrane materials such as paper or Tyvek® are not very breathable i.e. these materials have low gas flow rates and can be either fragile as in the case of certain papers, or expensive. It would be advantageous to reduce the area size of a vent relative to known breathable membrane wail components presently employed in medical gas sterilization packages while maintaining or improving gas flow in the sterilization process without sacrificing microbial barrier properties, improved gas flow may reduce ETO residuals and/or provide a faster sterilization process,

BRIEF SUMMARY

[00093 in one form of the present disclosure, a gas sterilization rigid vented tray is provided having: (a) a synthetic polymer tray wall having an exterior surface and an interior surface and comprising a base and upstanding base sidewali, with a foraminous wall portion in at least one of the base and sidewali; (b) filter media; (c) a foraminous cap; and (d) attachment means for the foraminous cap and tray wail whereby filter media is held by the cap to the foraminous wail portion. Preferably, the attachment means may include snap fit mechanica! attachment, adhesives, heat seals, fusion seals, ultrasonic welding, or combinations thereof. Also, it is preferred that the filter media be held between the cap and wall.

[00103 This tray may be provided with a lid attached to the sidewali e.g. at a flange by a continuous seal such as an adhesive seal or a heat seal. Preferably, the seal is a tamper evident heat seal. The lid is preferably transparent and advantageously may provide an unobstructed view of the tray contents. A variety of articles may be packaged within the tray including medical devices, pharmaceuticals, persona! care items or foodstuffs a!l of which may advantageously be sterilized to prevent spoiiage of the contents or illness from contact or ingestion of deleterious microbes, bacteria, viruses, molds, etc. It will be appreciated that the function of the tray and all of its Attorney Docket No. 20808- WO constituent elements, i.e. the tray wails including bottom any sidewaii and the lid which may be considered after package formation as a top wali, is to protect the contents of the package from contamination after the article is placed within the tray and the tray is enclosed by sealing with a lid. Thus the sealed tray including lid acts as a physical barrier to entrance of foreign matter e.g. microbes, yeast, molds, bacteria, dirt, airborne particulates, etc. from the environment exterior to the package into the package interior thereby protecting the article held therein. The tray and lid are therefore made of continuous structural materials which act as a physical barrier between the exterior of the package and the interior package. Once assembled with an article sealed inside, the tray package may be sterilized to render harmless any undesirabie matter contained therein with the package itself acting as a physical barrier against any further post- sterilization contamination.

[00113 Sn one embodiment of the invention, the foraminous wall portion has a continuous and surrounding projecting wall proximate to and enclosing the one or more openings (A) in a first section within an interior space defined by this projecting wall and has no openings within a second section which is also within the interior space defined b the projecting wall; and the cap has a panel and a continuous sidewaii depending therefrom and has one or more openings (B) through the panel in a first section within an interior space defined by the continuous sidewaii and has no openings within a second section which is also within the interior space defined by the continuous

sidewaii; and the cap is secured to the wall portion with the first and second cap sections oriented with respect to the first and second wall portion sections such that a path from openings A to openings B in its shortest distance DR is greater than a path in its shortest distance DT from an interior surface of the cap panel to an interior surface of the wall portion circumscribed by the projecting wall.

[0012] In another embodiment, the cap is formed e.g. by molding from filter media such as a porous sintered polymer and the filter media and foraminous cap are one and the same with the foramina being the small openings providing tortuous gas Attorney Docket No. 20808- WO passageways from the exterior of the cap therethrough to the interior compartment of an attached tray through one or more openings in the sidewali,

BRiEF DESCRIPTION OF THE DRAWINGS

[00133 Figure 1 is a perspective view of a vented gas sterilization rigid tray in accordance with the present invention,

[0014] Figure 2 is a perspective view of an alternative embodiment vented gas sterilization rigid tray with a sidewali located vent in accordance with the present invention.

[0015| Figure 3 is a plan view of the top of the tray depicted in Fig. 1 .

[00163 Figure 4 is a plan view of the bottom of the tray depicted In Fig. 1.

[0017] Figure 5 is a sectional view of the tray depicted in Fig. 3 taken along !ines 5-5.

[0018] Figure 8 is an enlarged view of a portion of the tray vent area of Fig. 5.

[00193 Figure 7 Is a sectional view of a foraminous cap and tray wali portion taken along lines 7-7 of Fig. 6.

[00203 Figure 8 Is an exploded view of the foraminous cap, filter media, and tray wall portion depicted in Fig. 7.

[00213 Figure 9 Is a sectional view of an alternative embodiment of the foraminous cap, filter media, and tray wall portion depicted in Fig. 7.

[00223 Figure 10 Is a schematic top view of an alternative foraminous cap and tray wali portion in accordance with the present invention.

[00233 Figure 1 1 is a sectional view taken along lines 11 -11 of Fig. 10. Attorney Docket No. 20808- WO

[0024] Figure 12 is an enlarged view of the cap, filter media, and tray portion depicted in Fig. 11 showing gas movement directions.

[0025] Figure 13 is an exploded perspective view of an alternative embodiment of the invention,

DETAILED DESCRIPTIO

[0028] The present invention relates to package sterilization containers which may be useful for sterilizing a variety of articles from food to medicai supplies. The inventive package is disposable, designed for single use applications. Advantageously, the invention may be beneficially employed as a disposable, intended for single use, medicai package sterilization container. Articles may be sealed within a tray according to the present invention to provide a physical barrier between the sealed tray interior and exteriorly located contaminants such as microbes and particulates in the

environment exterior to the package. The sealed package may then undergo gas sterilization processes to decontaminate the interior contents of the sea! tray.

[00273 Porous materials such as medical grade paper and Tyvek® spunbonded polyolefin sheets are often used for prior art gas sterilization packaging. The gas permeability of these materials is such that it allows for flow of steriiant and flushing gases into and out of the package being sterilized. These materials maintain the sterility of the package as they prevent bacteria and other microbes from entering the package. However, Tyvek®) is very expensive and paper does not typically have as good of a microbial barrier as Tyvek®. Both of these materials are opaque and obscure viewing of package contents when used, as is typical, as the fray lid o as a portion thereof.

[0028] According to filtration theory, the following five mechanisms contribute to the filtration efficiency of particles from a fluid stream by a filtration medium:

1. Interception ~ this occurs when a particle flows into direct contact with a part of the filter medium and becomes trapped. Attorney Docket No. 20808- WO

2. Inertia! Impaction - this occurs when a particle, due to its inertia, travels out of the fiow path and contacts the filter medium.

3. Diffusion Impaction - this occurs when a particle is made to contact the filter medium due to kinetic energy from surrounding gas molecules.

4. Gravitational Settling - this occurs due to normal gravitation effects on a particle causing it to settle into contact with the filter medium.

5. Electrokinettc Effects - this is when electrostatic charge of a material attracts

particles to a filter medium.

[00293 *ⁿ porous medical device packaging systems, the porous material allows for proper gas flow, but can also be thought of as a filter medium in order to provide microbial barrier. In high flow situations, such as during pressure changes due to ascent and descent of an airplane, Interception and Inertia! Impaction play a strong role in filtration. During low gas flow situations such as storage, Diffusion, Gravitational Effects, and ESectrokinetic Effects play a prominent role in filtration. Tyvek® and paper depend upon all of these methods to create a sufficient microbial barrier. The tortuous path inherent in the structure of Tyvek® as well as its electrostatic properties make Tyvek® an excellent microbial barrier for packaging medical devices. However, Tyvek® is not extremely permeable to gas and thus requires a large surface area to allow for a sufficient volume of gas flowing at a high enough rate to efficiently sterilize while preventing package rupture during pressure changes in the sterilization cycles, and to allow for efficient removal of sterilant gases. In certain embodiments of the present invention, a novel vent design utilizes an increased gas flow rate coupled with a thicker filter media or longer filtration path e.g. created by a change in flow direction with a predominant transverse or cross-directional flow through a vent which permits use of other filter media. This resuits in an adequate or improved microbial barrier through one or more of the following mechanisms:

1. Interception - a longer travel distance than the 2 to 8 mils typical with gas flow

across the thickness of paper or Tyvek®, results in more filter medium surfaces to intercept particles. Attorney Docket No. 20808- WO

2. Inertia! Impaction - a perpendicular change in flow direction should create flow

disturbances, which in turn create inertia and cause particles to escape the flow stream. Additionally, a Song, tortuous path creates more opportunities for contact with the filter medium. This tortuous path may be longer than that found in the prior art without reducing gas flow rates; indeed improved gas flow rates may be provided by the invention.

3. Diffusion Impaction - since the surface area at the opening or openings on one side of the vent may be selected to be greater than the surface area of opening(s) on the other side of the filter media and vent, and optionally offset therefrom, the flow rate of individual particles may change as gas traverses the material in its multiple directions (i.e. transverse or cross-directional to the sheet thickness), allowing for more diffusion impactions as the particle velocity changes in transit.

4. Gravitational Settling - gravitational effects, especially during storage periods, cause particles to fall, by located the vent on the tray rather than the lid, the vent is protected from particle entrance and any gravitational settling should be in a direction towards the exterior of the vent or orthogonal thereto rather than towards the interior or any contents.

5. Electrokinetic Effects ~ certain materials, such as polytetraflouroethySene (PTFE) which have a high capacity for static charge, can be used as the filter medium. 00303 in the present invention, both the cap and a portion of the tray wall are "foraminous" meaning that the cap and wall portion each has one or more openings (these openings may also be termed apertures or holes). These openings may be formed by a variety of means and in a variety of shapes and sizes. As a general rule the holes should be small enough to retain the filter media and, if needed, avoid any unwanted contact between the media and a packages contents, yet large enough to facilitate gas flow rates, while maintaining integrity of the tray wail and cap. The opening size and its passageway dimensions and the number of openings are parameters which may be controlled to provide the desired gas flow rate. Other considerations in design of hole size, number and shape include: volume of the tray to be sterilized, gas exchange rates, filtration resistance, spatial relationships between any Attorney Docket No. 20808- WO two or more notes. Suitable holes for various vents may be made by use of lasers e.g. a CO2 laser, hot needles, mechanical drilling, or punching. Alternatively, a vent may be provided by construction of a wall portion or cap made from a porous material such as porous sintered polymers e.g. a porous sintered poiyoiefin, preferably porous sintered polyethylene or PCTFE. In an embodiment using sintered material, the sintered cap or wall portion comprises the filter medium in addition to functioning as a cap and/or wall. Each method of hole creation has its own advantages and drawbacks e.g. use of punches is inexpensive and produces few fibers but chads may be created and the variable depth of trays may make set up and operation diff icult or add expense; use of drills may be precise but are expensive and produce undesirable fines and fiber debris; hot needles may be quick and useful particularly for thin gauge materials, but may cause heat distortion of the cap or wall for larger thicknesses; lasers have an expensive fixed cost and have safety considerations, require smoke & gas removal, but do not produce fibrous debris or fines and create openings having a nice glassy edge e.g. a bullnose shape which may be desirable. Sintering is a complex and expensive process. Due to their flexibility and capabilities to produce openings of a variety of shapes, sizes and configurations without fines, fibers or other undesirable particulate debris and their utility to also be employed in cutting operations e.g. for a flange, iasers are preferred.

[0031] In the present invention, a relatively small opening (or small opening area provided by a plurality of openings) in a rigid tray wall provides fluidic communication between the exterior of the package container and its interior so that gases may enter or exit the opening with passage through a filter which may be placed on either side of the opening. E.g. the filter provides a tortuous gas passageway from the tray exterior opening through the filter until reaching the interior compartment of the tray. The filter retaining cap has an opening to complete the fluidic communication with the tray interior. This cap opening ma also be relatively small (or have a small opening area provided by a plurality of openings). Alternatively, the filter and cap may be placed on the tray exterior so that gases enter and exit from the iray exterior through the cap then the filter and through the opening in the wail portion of the tray. Thus, the cap may be on either the tray interior or exterior with the filter media held between the cap and tray Attorney Docket No. 20808- WO wall in another embodiment, a wall portion or cap is formed from filter media itself rather than being a separate component. For example, an opening area and a wall may be provided with a porous sintered polymer cap which itself provides both desired filtration of microbes and desired gas flow rates.

[0032] Since the filtration efficiency, and thus microbial barrier, are improved with the inventive iray design, more permeable materials can be used as the porous medium. Examples of more permeable structures are open cell foams, sintered porous plastics, high loft nonwoven fabrics, and woven fabrics. Since these materials are more permeable, less surface area of material is required over or as part of a package wall. Since Tyvek® is typically the most expensive material in a packaging system, these alternate materials may be less expensive than Tyvek®, and a reduction in porous surface area required should a!low for a reduction in overall cost while providing the possibility of other benefits including Improved visibility of package contents.

Additionally, since the overall porous surface area on the package has been reduced, exposure of the environment to a porous surface area is reduced and, concomitantly, potential for contamination is reduced. A preferred novel tray design should allow for a cost reduction, increased gas flow rate, reduced stress on package seals, and an improvement In package microbiai barrier, and thus, patient safety. Advantageously, the venting means may be relocated from the lid to the tray thereby allowing use of a highly clear, transparent lid providing an unobstructed view of the contents of the tray. Also, the lid may be made of a nonporous or nonpermeable material and/or may also be formed of an oxygen and/or moisture barrier material. Advantageously, the lid may be made of a nonpermeable material which also functions as a retainer to prevent undesired movement of an enclosed article, e.g. during shipping and handling, by combining the functions of Sid and a retainer in a single component.

[0033] In the present invention, a novel gas sterilization package tray is provided, which suitably comprises a vented rigid tray for gas sterilization having: Attorney Docket No. 20808- WO

(a) a synthetic polymer tra wail having an exterior surface and an interior surface and comprising a base and upstanding base sidewait with a foraminous wall portion in at Seast one of the base and the sidewaii;

(b) filter media;

(c) a foraminous cap; and

(d) attachment means for the foraminous cap and the tray wal! whereby the filter media is held between the cap and the foraminous wal! portion and the attachment means are provided by snap fit or press fit mechanical fastening, adhesive, heat sealing, ultrasonic welding, or combinations thereof.

[0034] The present invention provides packages which have both microbial filtration and gas venting (i.e. communication back and forth between the package interior and exterior). Typically, the tray walls and Sid are formed of materials to provide a barrier to transmission of microbes, particulates, dirt, foreign matter, etc. between the exterior and interior of the package. The same materials typica!!y render the walls and lid

impermable to gas to the extent that any gas permeability is insufficient for utility in typical gas sterilization processes over reasonable cycle times which are typically about 8 to 12 hours for a iota! cycle. To accomplish gas venting the inventive package and tray equips the tray with a powerful yet small vent that has filtration capability. In a preferred embodiment of the invention this vent has (a) a first apertured wall !ayer having an opening of area "A", (b) a second apertured cap layer having an opening of area ^,SB". and (c) filtration media disposed between and in contact with layers (a) and (b). In a preferred embodiment, the first apertured wall layer has an opening of area "A" in a first section and has a second section having a nonapertured area greater than "A" and located in an area distinct from the apertured area. The second apertured cap layer is similarly defined with a first apertured section having an opening of area "B" and a second nonapertured section and the cap and wall layers are fixed relative to one another such that the apertured first section of the wal! layer overlays the second nonapertured section of the cap layer. Correspondingly, the nonapertured second section of the wall !ayer overlays the first apertured section of the cap layer. Thus, a long tortuous path through filter media held therebetween is provided from wal! opening Attorney Docket No. 20808- WO to cap opening, and this path is typically longer than the thickness of the filter media (which also corresponds to the distance between the inside surface of the wall to the inside surface if the cap.

[0035] It should be apparent that the materials selected for the wall layer and cap are typically sufficiently restrictive to air flow through their thicknesses that gas flow is diverted or directed to the openings in wall and cap and from these openings

transversely i.e. radially or perpendicular to the fiiter media sheet thickness. Preferably, the predominate gas flow into and out of the novel vent is caused to turn 90° which permits a gas transit distance greater than the thickness of the filter media sheet, and preferably at least twice this distance.

[0036 J Suitable materials which may be selected and used for layers of the tray wail and cap include many of the same materials thai may be used to construct a typical tray wall and may be monolayer or multilayer in construction. Lid stock for the lid used with the tray may also use similar materials. Examples of such materials include polyolefins, polyethylene terephtha Sates, polyamides, nylons, polystyrenes, polyacrylates, cyclic polyolefins, generally any polymer that is known for use in polymeric packaging. Such materials may be homopoiymers, copolymers, and their derivatives and blends thereof. Metal foils and meta!ized films are also contemplated. One or more functional properties may be contributed by one or more layers including desired levels of heat seaiability, optical properties e.g. transparency, gloss, haze, abrasion resistance, coefficient of friction, tensile strength, flex crack resistance, puncture resistance, abrasion resistance, portability, coiorfastness, flexibility, stretch or shrinkability, dimensional stability, barrier properties to gases such as oxygen, or to moisture, light of broad or narrow spectrum: including e.g. uv resistance, etc. Preferred materials for use as container walls, and Sidstock, include nylons, polyesters, polystyrenic polymers, and polyolefin e.g. ethylene or propylene homopoiymers or copolymers, or mixtures thereof in any number of layers, particularly, but not limited to, one to nine or 1 layers or more. Preferred polyolefins include ethylene homopoiymers or copolymers and may include low, medium, high and ultra-low or ultra-high density polymers. Examples are high Attorney Docket No. 20808- WO density polyethylene (HOPE), ethylene aipha-oiefin copoiymers (EAO) preferably utilizing butene-1 , hexene-1 , or octene-1 comonomer with a predominate ethylene comonomer portion) and including e.g. linear low density polyethylene (LLDPE), very low density polyethylene (VLDPE), plastomers, elastomers, low density polyethylene (LDPE) copoiymers of ethylene and polar groups such as vinyl acetate or ethyl acryiate e.g. ethylene vinyl acetate (EVA) or ethylene methyl acryiate (EMA) or ethylene acrylic acid copo!ymer(EAA)_t functional group modified polymers including e.g. anhydride modified EAOs. Propylene homopolymers and copolymers including polypropylene and propylene ethylene copolymer are useful, in some embodiments of the invention tray and !id layers in may utilize a gas barrier layer such as aluminum foil, poiyvinylidene chloride copolymers such as saran, polyacrylonitriles, or ethylene vinyi alcohol copolymers which provide high barriers to gas permeability or materials such as nylon which impede gas permeation to a lesser extent, or materials such as polyethylene which are generally not considered oxygen barriers. Gas barrier embodiments may be used for sterilization followed by purging the package interior with an inert gas and sealing or capping the vent to provide a hermetic package. This may be useful to package articles sensitive to the presence of oxygen over time.

[0037] Tray (including tray wall and cap), and Sid layers in accordance with the present invention may utilize a sealant layer which can include polyethylene, ionomer, polyacryionitrile, polyester, Barex®, or Surlyn®, Lid or trays may be multilayer coextrusions or laminates which may include more layers than those described above such as one or more adhesive layers to bond together layers which might otherwise have weak bonds and be subject to delamination or for other property enhancements or reasons of performance or cost.

[0038] Preferably, the synthetic polymer tray wall comprises a polyo!ef in, polyester, polyurethane, polystyrene, cyclic olefin copolymer, or combinations thereof. In several preferred embodiments, the synthetic polymer tray wall comprises a polyester terephthalate (PET) hornopo!ymer or copolymer, amorphous PET (aPET), glycol Attorney Docket No. 20808- WO modified PET (PETg), high impact polystyrene (HIPS), high density polyethylene (HDPE), polypropylene or combinations thereof.

[0039] packaging articles which have rough surfaces such as implants, it is advantageous to construct the packaging such that surfaces which contact these rough surfaces have a high abrasion resistance. One type of polymeric surface layer with advantageous abrasion resistance is based upon thermoplastic aromatic polyether polyurethane. DeerfieJd Urethanes, a subsidiary of Bayer, markets suitable

thermoplastic aromatic polyether polyurethane films under the trademark Durefiex© with grade PT9400 being particularl suitable, it is also advantageous to use this

polyurethane surface to protect poiished or treated article surfaces or any article surface for which abrasion resistance is required or advantageous,

[0040] in one especially preferred embodiment, the synthetic polymer tra wall comprises a multilayer structure having at least one layer of polyester terephthalate (PET) homopolymer or copolymer, and an interior surface layer comprising

polyurethane.

[0041] it is also advantageous to construct trays out of materials which can be readily thermoformed into packages of suitable rigidity. The typical packaging material for medical implants including femoral stem components has been sheets or films of polyethylene terephthalate glycol (PETG) because they have adequate rigidity and mechanical strength and good thermal formability. However, it is sometimes desirabie to have greater abrasion resistance than this material offers. This material may be used with a laye of thermoplastic aromatic polyether polyurethane in a multilayer

configuration having a polyurethane surface which faces the surfaces of the stem component This laminate is conveniently formed by melt laminating the polyurethane to the PETG. A preferred PETG for this lamination is Eastman's Eastar 8763 PETG resin. The thicknesses for both fiims should be compatible with both thermoforming the package configuration and providing adequate mechanical strength. A convenient range for the polyurethane is between about 0.01 and 0.025 inches while for the PETG it is between about 0.015 and 0.04 inches. Attorney Docket No. 20808- WO

[00423 in an alternative embodiment, the synthetic poiymer tray wall comprises a multilayer structure having an interior surface layer comprising poSyurethane or a cyclic olefin copolymer.

[00433 Adhesives useful in the present invention include permanent adhesives and pressure sensitive adhesives commonly available from many commercial sources. It is contemplated that acrylic and anhydride modified polymers may be employed as well as many adhesives which may be selected depending upon other material selections for the filter material as well as the gas diversion layer materials.

[00443 Additives and processing aides; natural and synthetic colorants, pigments and dyes; fillers such as calcium carbonate or carbon black, antimicrobial agents may also be incorporated into the tray wall, cap and/or filter media of the present invention.

[00453 The thickness of the multilayer structure laminate may be any suitable thickness that provides structural integrity, and desired combinations of properties which may vary depending upon the nature of the contents₁ usage requirements and which may include e.g. consideration of rigidity, structural support, tensile strength,

transparency, barrier properties, abuse resistance, heat resistance, heat sea!ability, scalping resistance, puncture resistance, abrasion resistance, optical properties, clarity, haze, gloss, printabslity, as may be determined by those skilled in the art in view of the present disclosure. It is expected that typical preferred thicknesses, for example, may be advantageously employed between about 50 pm and about 200 μπι for the lid. For many embodiments the synthetic polymer tray wall has a typical average thickness between about 20 mil to 60 mil (508-1524 microns), and preferred thickness of 30 to 50 mil (762-1270 microns); more preferably about 40 mil (1016 microns).

[00463 P°^r many embodiments the lid has a typical thickness between about 2 to 20 mil (51 -508 microns (μ})„ and preferred thickness of 2-10 mil (51-251 microns); more preferably 3-6 mil (76-152 μ). Attorney Docket No. 20808- WO

[0047] For many embodiments the cap has a typical thickness between about 15-60 mil (381 -1524 μ), and preferred thickness of 20-50 mil (508-1270 microns; more preferably 30-40 mil (762-1016 μ).

[00483 The cap may be a snap-on rigid cap or a semi-rigid cap or even a sheet or film cap which is fastened to the tray wail by adhesive or fusion e.g. by heat sealing or ultra-sonic welding or fastened by a combination of means, for example, by mechanica! means such as a snap-on cap coupled with an adhesive which sets over time,

[0049] According to the present invention a filtration media is used to provide gas transport between opposing exterior and interior sides of a package wall while inhibiting, reducing or preventing passage of smali particles, foreign materials, viruses, and microbes.

[0050] Suitable filtration media may be fibers, disks or sheets and may be polymeric, cellulosic or non-celSuSosic or a combination thereof. Suitable oeSlulosic materials include cotton including air laid, carded, fibrous cotton wadding, wood pulp such as fluff pulp and non-wood plant counterparts. Suitable non-ce!luiosic materials include

thermoplastics that can be used to provide porous thermoplastic filter media sheets which inciude but are not limited to, homopolymers and copolymers of poiyoiefins, polyurethanes, polyamides, nylons, polycarbonates, poly (ether sulfones),

f!uoropolymers such as po!yietrafluoroethyiene (PTFE) and polyvinylidene fluoride

(PVDF), and mixtures thereof. A preferred thermoplastic is a poiyoiefin. Examples of suitable poiyoiefins inciude, but are not limited to: ethylene vinyl acetate; ethylene methyl aery late; polyethyienes; poly propylenes including nonwoven spunbonded

polypropylene: ethylene-propylene rubbers; ethylene-propylenediene rubbers; po!y(1- butene); polystyrene; poly(2~butene); poly(1~pentene); poiy{2~pentene); po!y(3-methyl~1 - pentene); poly(4~methyi~1-pentene); 1 ,2-poiy~1 ,3-butadtene; l4~poSy~1 ,3-butadiene; polyisoprene; poSychloroprene: poiy(vinyi acetate) ; poly(viny!idene chloride); and mixtures and derivatives thereof. A preferred poiyoiefin is polyethylene homopoiymer or copolymer. Examples of suitable polyethyienes include, but are not limited to, low- density polyethylene, high density polyethylene, ultra-high molecular weight Attorney Docket No. 20808- WO polyethylene, ethylene aSpha-oSefin copoiymers such as linear low density polyethyiene or very low density polyethylene, and derivatives thereof. Suitable filter media sheets made of porous sintered thermoplastics such as polyolefins may be made from the materials and by the processes as more fully described in U.S. Patent No. 6,551 ,608, U.S. Publication No. 2010/0104845, and EP 1 644 098 B1 each of which is hereby incorporated by reference in its entirety. Other filter media may include e.g. air iaid. wet laid or dry laid nonwovens of materials such as polypropylene, polyethylene, polyester, nylon, celluiose or combinations thereof. Electrostatic air filtration materials such as Technostat™ from Holiingsworth & Vose may be adapted for use e.g. air laid

polypropylene fiber mats which are needle punch bonded to a polypropylene

spunbonded point bonded web,

[0051] The filter media may also be made from open ceiled foamed polymers. It has long been known that a "foam" of poiyurethane can be prepared by reacting a

polyisocyanate with a poly-hydroxy compound in the presence of a small amount of water which acts as a blowing agent. The water reacts with isocyanate groups producing carbon dioxide gas which forms small gas bubbles or ceils in the "foam" when the poiyurethane sets.

[0052] Such "foam" products have a structure made up of numerous individual ceils which generally are constructed of a three dimensional skeletal structure of

interconnected strands with membranes or windows joined to the skeletal structure such that they partition contiguous cells. The skeletal structure in these celluiar materials is usually considerabSy thicker than the membranes or windows. When the foam windows are removed, an open-celled reticulated foam is produced which permits fluids to flow through the remaining skeletal structure. A method for producing reticuiated foam is described in U.S. Pat. No. 3,175,025 to Geen. Commercially available open ceiled foamed polymers are available from many sources including UPF Technologies of Georgetown, Massachusetts, U.S.A. Very fine cell poiyurethane foam and processes for making the same are further described in U.S. Patent os. 5,034,422 and

6,136,878. Attorney Docket No. 20808- WO

[00533 ^be porous thermoplastic materials of the invention may further comprise materials such as lubricants, colorants, fillers, processing additives, and mixtures thereof. Suitable fillers include, but are not limited to: mtcrocrystalline cellulose, ceiluiosic fibers, titanium dioxide, carbon black, siliceous fillers, polyethyiene fibers and filaments, and mixtures thereof.

[0054] In addition, antimicrobial, anti-bacterial, anti-viral and anti-mycotic agents may be incorporated within the filter medium structure. Suitabie agents include e.g., natural antimicrobial agents; polymeric antimicrobial agents; phenolic and chlorinated phenolic compounds; resorcinol and its derivatives; bisphenolic compounds; benzoic esters; halogenated carbaniiides; thazoiines; trichioromethylthiol ides; metal salts; silver ions; and mixtures thereof as further described in U.S. Patent No. 6,551 ,608, It is desirable that the filter media be contained to prevent direct contact with the tray contents e.g. a medical device to avoid contact transfer of any media material or additives via the device to a patient.

[0055] Preferably, this filtration media is a microporous structure which may be e.g. a sintered thermoplastic e.g. sintered porous poSyo!efin e.g. an ultra-high molecular weight polyethylene, or an open celled polymeric material such as those sold under the trademark Porex® by Porex Technologies GmbH of Aachen, Germany. Preferred materials are chemically Inert, and have excellent physical properties including high tensile strength and temperature resistance to withstand elevated temperatures and steam employed in gas sterilization processes. Other desirable properties for preferred embodiments of the invention include filter media having oleophobic and hydrophobic properties and uniformity of pore size. Also, porous PTFE material which is an expanded po!ytetrafluoroethylene (PTFE) polymeric film is commercially available under the Porex trademark. Expanded polytetrafluoroethylene (PTFE) films are further described in U.S. Patent Nos. 3,953,568; 4,187,390; 4,945,125; 5,066,683; 5,157,058; and 5,362,553 each of which is hereby incorporated by reference in their entireties. Expanded PTFE materials are also available commercially from Tetratec, Philadelphia, Pa. as Tetratec #1305 and from Sumitomo Electric Industries, Osaka, Japan under the Attorney Docket No. 20808- WO brand Poreflon® WP-100. An expanded PTFE fiSm typically comprises a plurality of nodes interconnected by fibrils to form a microporous structure. Sintered porous polymers may be used to form a cap and/or wail portion in accordance with the present invention thereby combining the filter media and the cap and/or wall into a single component.

[0056] Porous filter media according to the present invention have a preferred average pore size between about 1 to 500 microns. Advantageously, the pore size will preferably have substantial uniformity, although materials with a range of pore sizes are suitable. Filter media such as sintered polymers from Porex are compatible with steam and ethylene oxide sterilization processes and may be ultrasonicaily welded or heat sealed.

[0057] Various materials may be used for the filter media and the tray and cap structures. Gurley Hill porosity values may be used to select the materials. "Gur!ey Hill porosity" refers to the air resistance of an approximately 8.45 cm² (1 in²) circular area of test sample using a pressure differential of 1.22 kPa and Is measured in accordance with International Standard ISO 5636-6, "Paper and board— Determination of air permeance and air resistance (medium range)— Part 5: Gurley method." Gurley Hill porosity values are reported in the amount of time (seconds) required for a given volume (100 cm³) of air to pass through the test sample, in general, Gurley Hiil porosity values indicate the gas barrier strength of a sample; lower values indicate the sample is more porous. Samples with Gurley Hill porosity values greater than 300 seconds are generally considered substantially non-breathable.

[0058] For many embodiments the filter media has a typical thickness between about 25 to 250 mil (635 - 6350 μ)_; and preferred thickness of 60 to 125 mil (1524-3175 microns).

[00593 Referring now to the Drawings, Figure 1 depicts a perspective view of a vented, rigid tray 10 in accordance with the present invention. Tray 10 has a tray wall 11 , preferably made from synthetic polymer, and having an exterior surface 12 and Attorney Docket No. 20808- WO interior surface 13. The tray wall 1 1 comprises a base 14 and upstanding base sidewall 15. The sidewai! 15 may have a sidewall flange 16 which is adapted to receive a heat sealabie or adherabie !idstock on an upper flange surface 17. The sidewall 15 may also be equipped with an interna! rim 18 for receiving an article-stabilizing insert (not shown). The tray 10 is also equipped with a vent 19 in its base 14. The vent 19 has a

foraminous cap 20 having a plurality of holes 21 . The base 14 and base sidewall 15 are preferably integrally formed of a single polymeric sheet e.g. by thermoforming and the base 14 and base sidewall 15 portions of the tray wall 1 1 meet at base perimeter 22.

[00603 Referring now to Figure 2, an alternative embodiment of the tray of Fig. 1 is depicted with a different vent location. Fig. 2 depicts a perspective view of a vented, rigid tray 1 10 in accordance with the present invention. Tray 110 is similar to the tray 10 of Fig. 1 except for the vent location. Thus, tray 1 10 has a tray wall 11 preferably made from synthetic polymer, and having an exterior surface 1 12 and interior surface 113. The tray wall 11 1 comprises a base 1 14 and upstanding base sidewall 1 5. The sidewall 115 may have a sidewai! flange 116 which is adapted to receive a heat sealabie or adherabie Sidstock on an upper flange surface 1 17. The sidewall 1 15 may also be equipped with an internal rim 1 18 for receiving an article-stabilizing insert (not shown). The tray 1 10 is also equipped with a vent 1 19, however in this embodiment the vent 1 9 is located in its sidewai! 1 15, The vent 1 19 has a foraminous cap 120 having a plurality of holes 121. The base 114 and base sidewai! 1 15 are preferably integrally formed of a single polymeric sheet e.g. by thermoforming and the base 114 and base sidewai! 1 15 portions of the tray wall 1 1 1 meet at base perimeter 122. By locating the vent 119 in the sidewai! 115 the possibility of contamination by contact of the base with contaminates e.g. liquids present on a surface upon which the tray 110 sits is lessened.

[00613 Referrin now to Fig. 3, a top plan view of the tray 10 of Fig. 1 is shown. In this view, rigid tray 10 having tray wall 1 1 clearly shows the vent 19 having a foraminous cap 20 with holes 21 In this particular embodiment, the vent 19 is centrally located in the base 14 within the base perimeter 22. Tray 10 has a tray wall 1 1 and interior surface Attorney Docket No. 20808- WO

13 of the tray wa!l 1 1 equipped with a rim 18 for receiving a stabilizing insert (not shown). Tray wall 1 1 has a sidewali flange 16 with an upper flange surface 17 for receiving an attachable, preferably clear and transparent, lid. Upper flange 17 is

provided in one corner with pull tab grooves 23 to assist in lid removal, A lid may be attached to the tray 10 by several means. For example, the lid may be a plastic snap- on iid where the Sid has an outer rim which expands and snaps around flange 16.

Preferably, the Sid will be a heat scalable, thermoplastic film which may be heat sealed to the upper flange surface 17 thereb providing a continuous seal around an interior compartment 24 of the tray 10. Advantageously, the lid may be sealed entirely around a perimeter 25 which defines a tray opening into its internal compartment 24, while the while seal does not extend into an flange area extension 26 having pulitab grooves 23, These grooves 23 and proxtmate extension area 26 is an area of the flange 17 which is not heat sealed and therefore a user may grasp a lid edge and manually, peelably remove the lidding film from the upper flange surface 1 .

[0062] The lidding film used in various embodiments of the invention, may be chosen to be heat sealabte to compatible material on the upper flange surface 17 to provide a strong heat seal which is also manually peelable and may , in addition, provide evidence of a continuous seal, or Sack thereof, through a tamper evident feature in which, upon removal of the lid film by peeling, the Sid is transformed from transparency to a mi!ky white opaqueness. This is a visual indicator which may be used to check whether the iid has been properly sealed and whether it is properly sealed just prior to opening. Prior to removal the Sid is continuously heat sealed about the perimeter 25 of the upper flange surface 17 thereby enclosing the interior compartment 24. Prior to peeling the lid attached to the upper flange surface should be transparent in appearance. Upon detachment from the flange surface 17 the lid should become opaque and have a milky white appearance: if it does not then it may not have been properly sealed wherever there is a discontinuity in the opaqueness.

[00633 Use of a transparent clear lidding heat sealed to the upper flange surface 17 also advantageously provides a tray having an unobstructed view of its interior. The Attorney Docket No. 20808- WO interior compartment 24 of tra 10 may also utilize a transparent insert which is seated on rim 18 to stabilize an article held therein and this insert may likewise be of

transparent construction to permit an unobstructed view of the article held within. In many applications, this article will be a medical device such as an implantable prosthetic device such as a hip joint, knee joint, or other medical devices e.g. a catheter, scalpel, etc. The vent 19 is constructed so that sterilant and purge gases may communicate through plurality of holes 21 between the interior compartment 24 and the environment exterior to the tray 10 while at the same time the vent filters out unwanted, deleterious materials and agents such as harmful bacteria, molds, viruses, dust, etc.

[00643 Referring now to Fig. 4, a bottom plan view of the tray 10 of Figs. 1 and 3 is shown, in this view, rigid tray 10 having tray wall 11 clearly shows the vent 19 having a foraminous wall portion 27 with holes 28. In this particular embodiment, the vent 19 is centrally located in the base 14 within the base perimeter 22. Tray 10 has a tray wali 1 1 and exterior surface 12 of the tray wall 11 equipped with a rim 18, Tray wali 1 1 has a sidewa!l flange 16 with an lower flange surface 29 connected to rim 18 which in turn is connected by tapering side wall section 30 to base perimeter 22. Flange 16 is provided with a flange extension area 26 in one corner with pull tab grooves 23 which on its reverse side assists in lid removal. A lid may be attached to the tray 10 by several means. For example, the lid may be a plastic snap-on lid where the lid has an outer rim which expands and snaps around flange 16 removably hooking on the tower fiange surface 29, The vent 19 is constructed so that sterilant and purge gases may communicate through plurality of holes 28 which extend from the exterior surface 12 of the tray wall base 14 to th interior surface (See Fig. 3) so that these gases pass through a filter media (See Figs. 6-8) between the interior compartment (See Fig. 3) and the environment exterior to the tray 10 via foraminous cap holes 21 (See Fig. 3) and foraminous wall portion holes 28. In this manner the vent filters out unwanted, deleterious materials and agents such as harmful bacteria, molds, viruses, dust, etc. while allowing sterilant, purge and atmospheric gases to exchange between the inside compartment 24 (see Fig. 3) of the tray and the outside environment external to the tray 10, The exterior surface 31 of the base 14 is circumscribed by base perimeter 22 and Attorney Docket No. 20808- WO may be provided with a plurality of raised extensions or feet 32. These feet may be integraily formed e.g. by therm of orming. The feet 32 provide a separation between the tray vent 19 and any flat surface upon which the tray rests e.g. a surgical table or sterilizing tray. In this way the feet facilitate gas passage to and from the vent while minimizing the possibility of contact with any liquids or condensation which may be present on tables or trays or surfaces upon which the tray rests. 006S| Referring now to Fig. 5, a sectional view of the tray 10 depicted in Fig. 3 taken along lines 5-5 is shown. The rigid tray 10 has a tray wall 1 1 which comprises a base 1 and upstanding base sidewal! 15 forming an interior compartment 24. In this view, the vent 19 is clearly shown with its foraminous cap 20 having holes 21 connected to the sidewal! 15 at its foraminous wall portion 27 with attendant wall portion holes 28, Filter media is held securely between the cap 20 and wall portion 27 (See Fig, 8), In this particular embodiment, the vent 19 is centrally located in the base 1 within the base perimeter 22. Tray 10 has a tray wall 11 with an exterior surface 12 and opposing interior surface 13. This interior surface 3 of the tray wail 1 1 has a peripheral rim 18 formed therein. Tray wall 11 has a sidewal! flange 16 with an upper flange surface 17 and lower flange surface 29 connected to rim 18 which in turn is connected by tapering side wall section 30 to base perimeter 22. Flange 16 is provided with a flange extension area 26 in one corner with pu!l tab grooves 23 which assist in lid removal. Vent 19 may be recessed slightly, as shown, to prevent contact of the fray or table surface with the area adjacent to the vent 19 and this recess may also facilitate gas flow into and out of the vent holes 28. This may be useful e.g. where the tray is subjected to conditions where steam condensation may occur since a recessed location e.g. on the tray base may assist in protecting the vent from condensate. Optionally, projecting from an exterior surface 31 of the base 14 are a plurality of feet 32 which elevate the exterior base surface 31 to space apart the vent 19 from a surface such as a flat tray or table. This spacing further facilitates prevention of contact of the area adjacent the vent 19 with a tray or table surface and any contaminates or liquids which may be present thereon and further may facilitate the aforementioned gas transfer. Attorney Docket No. 20808- WO

[0066] Referring now to Fig. 6, an enlarged view is shown of the vent 19 of Fig. 5. Vent 19 comprises a foraminous cap 20 having holes 21 and a mating foraminous wa!i portion 27 which has holes 28 which are preferabiy axially offset from alignment with holes 21. Held between cap 20 and wall portion 27 are filter media 33. Attachment means are provided to connect together the foraminous 20 and the tray wail 11 and the foraminous wall portion 27 These attachment means are preferabiy snap fit attachment means whereby filter media 33 is held between the cap 20 in the foraminous wall portion 27. The foraminous wail portion 27 has a continuous projeciing wail 34 proximate to and surrounding the foraminous wall portion 27 which by definition contains at least one hole, and in this depicted embodiment a plurality of holes 28. In the embodiment depicted in Fig. 6, the projecting wali 34 extends from the tray wall 11 towards the interior compartment 24 of the tray 10 (See Fig, 5), In an aiternative embodiment, the projecting wall of the vent may extend from the tray wall 11 towards the exterior of the tray in which case the filter media and cap placement are made on the exterior surface of the tray. Returning again to Fig. 6, the projecting wail 34 may be provided with the least one recess 35 as the projecting wail 34 extends away from base 14. in a preferred embodiment, this recess may be a continuous recess about the periphery of a continuous projecting wall 34. While a circular projecting wall is depicted, it is contemplated that projecting walls of various shapes may be employed. For example, it may be desirable to utilize a symmetrical shape or asymmetrical shape, either having a configuration which allows cap placement along any dimension of rotation about an axis perpendicular to the base, or alternatively which requires a specific location for engagement of the cap 20 with the wall portion 27. The advantages of the specific placement of the cap 20 to the wail portion 27 are further discussed below with respect to Figs. 10 - 12. Also, a plurality of recesses may also be employed to effect cap placement positioning as well as for securing the cap 20 to the projecting wall 34. Returning again to Figure 6, from recess 35 the projecting wall 34 extends outward to a perimeter hold position 38 whereupon the projecting wall turns inwardly and then downwardly and then turning parallel to the base 14 to create a recess 37 for holding the filter media 33. This filter media 33 is placed in the filter media recess 35 where it is enclosed by and securely held by foraminous cap 20. The foraminous cap 20 Attorney Docket No. 20808- WO has a at least one hole and in this depicted embodiment a plurality of holes 21. Cap 20 has a pane! 38 and a continuous cap sidewal! 39 depending therefrom. The cap 20 has a detent 40 which fits into the recess 35 of the projecting wa!l 34 to provide a snap fit. Thus, a cap 20 having a pane! 38 and a continuous side wa!i 39 depending therefrom with the sidewail 39 having at feast one detent 40 may be employed to cooperate with the projecting wall 34 to provide snap fit aitachment means. Each detent and recess is adapted to cooperate with each other to provide attachment means whereby a cap 20 is securely connected to the tray wall 1 1 . 0067j Referring now to Fig. 7. a sectional view of a foraminous cap 20 and fray wall portion 27 taken along lines 7-7 of Fig. 6 is shown. In figure 7, the cap 20, filter media 33 and foraminous wai! portion 27 comprise a vent 19 in accordance with the present invention. The solid headed arrows show gas flow between the interior of the tray through openings in the cap 20 provided by a plurality of holes 21 across the fitter media 33 and into and out of openings in the foraminous wall portion 27 provided by a plurality of ho!es 28. in use vent 19 permits sterilizing gases to be admitted from the tray exterior through holes 28, across the filter media 33 and out of holes 21 into the tray interior whereupon the damaging, dangerous or undesirable microbes, molds, yeasts, spores, viruses, bacteria and the like are eradicated to render contents of an enclosed tray sterile. The sterilant gases are flushed from the tray interior by application of an vacuum and re-admittance of atmospheric or purging gases. This sterilant, vacuum , gas exchange operation may be cycled multiple times to effect sterilization. This process which typically employs ethylene oxide as a sterilant which may be performed under elevated temperatures and with or without elevated humidity can cause changes in pressure or pressure differentials which stress not only lid to tray seals, but also the attachment means for securing the filter media over the openings in the tray wall. The cap 20 may be held mechanically e.g. by snap fit means and/or may also be held by heat seals, ultrasonic welding, adhesives or combinations thereof.

[00883 Referring now to Fig. 8, an exploded view of the foraminous cap 20, filter media 33, and tray wall portion 27 of vent 19 depicted in Fig. 7 is shown. In assemble of the vent 19, the foraminous wail portion 27 of tray wall 1 1 is formed into a shape Attorney Docket No. 20808- WO having a projecting vval! 34 with a recess 35 which is adapted to receive a

corresponding detent 40 of cap 20. Portion 27 is further formed to have a f ilter media recess 37 for receiving filter media 33. Alternatively, the cap 20 may be formed with either or both of a recess for receiving the filter media 33 and/or one or more recesses for receiving a corresponding detent which detent could be made in the wall portion e.g. on the interior side of a projecting wall 34 and into which a cap could snap fit in a nesting arrangement. A bottom panel 41 of the wali portion 27 has a plurality of openings which could be slots, ovals, or of various sizes or shapes, but preferably are generally circular holes 28 which may be formed from variety of well-known means e.g. laser perforations, die punched, hot needle formed, etc. The filter media may employ a variety of materials which can range from cellu!osic materials such as cotton to synthetic non-cellulosic polymers such as polypropylene nonwovens, sintered polyethylene discs or open celled foamed polymers, etc. The foraminous cap 20 has a panel 38 through which are provided a plurality of holes 21 as for the wall panel 41 . The dimensions of the filter media recess 37, projecting wali recess 35, cap detent 40 and thickness of the filter media are such that, upon attachment of the cap 20 to the wall portion 27 , the filter media 331s securely held therebetween in a manner which precludes filtration defeating channeling between the holes in the cap 20 and the holes 28 in the wall portion 27.

[0069] Referring now to Fig. 9, an alternative vent 219 to the vent 19 depicted In Fig. 7 is shown having a foraminous cap 220, filter media 233, and foraminous tray wall portion 227. In this embodiment the vent 219 is similar to that described above for Figs. 6-8 except that a single opening or hole is used in either or both of the cap 220 and/or wall portion 2:27. Depicted are a cap 220 having a single hole 221 and a wail portion 227 also having a singie hole 28. This embodiment contemplates use of filter media 233 which is self-contained e.g. a cohesive sintered disk having sufficient integrity that it does not disintegrate in use or a filter media having a woven or nonwoven containing wall e.g. as a sachet or self-contained semi-permeable pouch.

[00703 Referring now to Figs. 10-12 an alternative form of the vent 19 of Figs. 6-8 is depicted in the form of a transverse flow vent 319. Attorney Docket No. 20808- WO

[0071] Figure 10 is a schematic top view of an alternative foraminous cap 320 and tray wall portion 311 in accordance with the present invention. An opening or slot-like hole 323 in foraminous wati portion 327 is shown by dotted line to axialiy offset from the cap opening 321. Although a single hole is shown in both cap 320 and wa!! portion 327, it is contemplated that a plurality of hoies couid be grouped together to achieve the same effect, as further described below. Thus, slot hole 321 cou!d be e.g. three holes in a Sine within the same outline of the slot or an array of e.g. 9-12 small holes could be bunched together on one side of the cap 320 while in a similar fashion the single slot 328 of the wali portion 327 could be transformed into a plurality of holes in a line or bunched array yet distalSy located from the cap holes 321.

[00723 Figure 11 is a sectional view taken along lines 1 1-1 1 of Fig. 10. in this sectional view a similar vent component arrangement to that of vent 19 in Figs. 6-8 are shown except for the openings or holes in the cap 20 and wall portion 27. A tray wall 311 has a foraminous wail portion 327 with the projecting wall 334 having a recess 335 time which is seated filter media 333 held in place by a foraminous cap 320 which is connected to the wail portion 327 by snap fit aitachment means. The cap 320 is provided with at least one detent 340 and the projecting wall 334 has a mating recess 335 to receive the detent 340 thereby providing retention of the cap 320 by pushing and stretching the detent 340 over the projecting wall 334 until it snaps back with the cap detent 340 nesting within the recess 335 of the projecting wall 334 as for the embodiment of Figs. 6-8. The detent and recess are adapted to cooperate to provide the attachment means whereby the cap is securely connected to the tray wall, it should also be noted that the attachment means may be provided by use of an adhesive, heat sealing, ultrasonic welding, mechanical attachment for exampie by snap fit or press that means, or combinations thereof.

[00733 Figure 12 is an enlarged schematic view of the cap 320, filter media 333, and an the foraminous tray wall portion 327 defined by the projecting wall 334 as depicted in Fig. 1 1 and the interior space thereof. Fig. 12 illustrates gas movement directions by solid headed arrows. Vent 319 is depicted in Fig. 12 showing a Attorney Docket No. 20808- WO foraminous wall portion 327 having a hoie 328 therethrough in a f irst section within the interior space defined by the projecting wail (See Fig. 1 1 ). Also, within the interior space defined by the projecting wail is a second section which has no openings. The cap 320 has a pane! 338 with an opening or hoie 321 therethrough in a first section which is also within the interior space defined by the continuous side-wall 339 which depends from panel 338. The cap 320 also has a second section within an interior space defined by the continuous stdewa!i 339 which has no openings. The cap 320 is secured to the wall portion 327 with the first and second cap sections oriented with respect to the first and second waii portion sections such that a path from opening 328 opening 321 in its shortest distance D_R is greater than a path from an interior surface 348 of the cap 320 to an interior surface 347 of the wail portion recess 335 in its shortest distance Dr. The shortest distance Djalso corresponds to the thickness of the filter media 333. in one preferred embodiment, the relationship between these two shortest distances DR and D_T wi!i satisfy the formula DR ≥ 2D_T The cap 320 and iray wall 311 may

advantageous !y have orienting means for positioning opening or hole 328 in a spaced apart relationship to the opening or hole 321 , along a plane of the cap panel 338 or bottom pane! 341 of the wal! portion 327, These orienting means may comprise at !east one of: (i) mating cap and wali portion projecting wail configurations which preclude transverse alignment of openings of the cap 320 with the openings of the foraminous wali portion 327; locating notches or visual indicators in the cap 320 and wali portion 327; and (iii) an asymmetric cap perimeter; and (iv) positioning lock tabs.

[0074] Referring again to Fig, 12, as illustrated by the solid headed arrows gas flow may enter o exit opening 321 and proceed longitudinally or transversely through filter media 333 entering or exiting opening 328 to provide a long pathway through the filter media 333. This long transverse flow path advantageously in accordance with the present invention allows for a low profile vent to be provided on a rigid tray where this low-profile vent 319 is capable of providing a high degree of filtration undesirable partic!es and/or organisms while permitting a high gas volume to flow into and out of the tray interior during gas sterilization processes. This helps to prevent seal rupture between the tray and led and aiso around the vent itself. Thus is achieved a highly Attorney Docket No. 20808- WO desirable combination of filtration efficiency, effectiveness, and stress reducing gas flow rates.

[0075] Referring to Fig.13, an exploded view is presented of the inventive package. A vented rigid tray indicated generally by 410 having a continuous tray wall 411 with exterior surface 412 and interior surface 413, base 414 and base sidewall 415. The base sidewaSI 415 has a continuous perimeter sidewall flange 416 with an upper flange surface 417. Sidewall 415 is equipped with an internal rim 4 8 for receiving a retainer insert 451. A microbe filter vent 419 is shown in an exploded view having a foraminous cap 420 with holes 421 , filter media 433, and a foraminous wall portion 427 with the projecting wall 434 forming a filter media recess 437. Cap 420 comprises a panel 438 and sidewall 439 which is depicted as having a generally rectangular shape which may be asymmetrical such that the May only be connected to wall portion 427 and a single configuration. Cap 420 may be mechanically fastened wall portion 427 by manually pushing the cap for 20 against the wail portion 427 with filter media 433 therebetween which causes cap sidewall 439 to distort and extend about projecting wall 434 with detent means of the cap 420 springing back into a recess four and 35 of the projecting wall 4 to 34 to securely hold the cap 420 two wall portion 427 with filter media 433 therebetween. Optionally, an adhesive may be applied to the perimeter surface of the projecting wall 434 which provides upon setting of the adhesive a hermetic seal about the perimeter. An article 450 depicted as a generic plug may be inserted into the tray 410 and secured against movement therein by a projection formed in fray base 414 and by provision of retainer insert 451 having a shaped engagement means for securing the article depicted as rejection 453 whereby the retainer insert 451 is inserted within the tray such that the retainer insert perimeter edge 452 engages tray side wail Internal rim 418. This retainer insert 451 may also be configured to snap fit into a recess adjacent the internal rim 418 on the interior surface 413 of the iray wall 411. The retainer insert may be manually removable which may be facilitated by providing a finger hole opening. A lid 454 which is preferably transparent may be made from a thin film or clear plastic sheet and adhered to or heat sealed or otherwise fastened to the upper flange surface 41 of the tray sidewall flange 416 thereby providing and hermetic seal about the Attorney Docket No. 20808- WO perimeter of the tray for 410 where the id is connected to the tray side wall.

Alternatively the retainer insert 451 may be designed to act as the lid itself and attached by suitable fastening means which may include mechanical fastening means, adhesive, heat seal or combinations thereof. Furthermore, it will be appreciated that a rigid lid may be utilized in the present invention wherein the filter vent for 419 may be located therein rather than on the tray side wall or base. In this alternative embodiment the tray lid and/or retainer insert acts as an upper tray wall to enclose and seal within the interior of the tray for 410 the article 450 while providing filtration and vent means through the top of the tray via ltd and/or retainer insert.

[00763 Will be appreciated that the filtration vent may utilize a material which combines the functionality of the filtration means as part of material forming the cap or foraminous wall portion. Thus a foraminous cap or lid containing the same may be said to be a spring cover whereby the cap or lid has sufficient extensibility to be disiortabie about its perimeter whereby it may be compressed or extended to engage a tray projection or recess to provide mechanical fastening thereto.

[0077] In an alternative embodiment of the invention, a spring cover ma be provided which comprises filter means for filtering microbes and particulates, and fastening means for connecting said cover to a tray. This spring cover may be a foraminous cap which may be attached as described above either trapping filter media between the cap and a portion of the tray wall having an opening therein or the cap may be formed from filter media itself such as porous sintered po!yolefin. The fastening means for this may be mechanical fastening means, for example, having a perimeter extensible resilient wall which may be pressed over a projection from the tray wall to engage a perimeter cap detent with a recess on the tray wail projection or alternatively may be compressed and fit within a projection from the tray wall to engage a perimeter recess located within that projection such that the cap detent expands to engage the interiorly located internal perimeter recess. Alternatively the spring cover may be a iid equipped with filter means and said filter means may be the same as the foraminous cap described above. A spring cover lid may be similarly fastened by using a disiortabie perimeter which may be

3 i Attorney Docket No. 20808- WO compressed or extended to engage a sidewa!l tray flange or a perimeter recess within the sidewa!! of the tray.

[0078] Described herein are trays that are equipped with a vent and preferred embodiments of such trays may also advantageously provide easy access to remove contents within the tray. The novel trays may be manually opened without use of scissors or other tools, preferably using easy to peel open systems such as peelab!e seals. The lid seal may be either peelable or non-peelabSe, Advantageously, the lid seal is a peelable seal which is peelabie along at least a portion of the seal or along the entire seal to provide access to the tray contents. "Peelable sea!" and like terminology is used herein to refer to a seal, and especially heat seals, which are engineered to be readily peelable without uncontrolled or random tearing or rupturing the packaging materials which may result in premature destruction of the package and/or inadvertent contamination or spillage of the contents of the package. A peelabie seal is one that can be manually peeled apart to open the package at the seal without resort to a knife or other implement to tear or rupture the package. Many varieties of peelable seals are known in the art, such as those disclosed in U.S. Pat. No. 4,944,409 (Busche et al.); U.S. Pat. No. 4,875,587 (LuSham et al.); U.S. Pat. No. 3,655,503 (Stanley et al.); U.S. Pat. No. 4,058,632 (Evans et al.); U.S. Pat. No, 4,252,846 ( omesberg et al,); U.S. Pat. No, 4,615,926 (Hsu et al.) U.S. Pat. No. 4,666,778 (Hwo); U.S. Pat. No. 4,784,885 (Carespodi); U.S. Pat, No. 4,882,229 (Hwo); U.S. Pat. No. 6,476,137 (Longo); U.S. Pat. No. 5,997,968 (Dries, et al.); U.S. Pat. No. 4, 189,519 (Ticknor); U.S. Pat No, 5,547,752 (Yanidis); U.S. Pat. No. 5,128,414 (Hwo); U.S. Pat. No. 5,023,121 (Pockat, et a!.); U.S. Pat. No. 4,937,139 (Genske, et a!.); U.S. Pat. No. 4,916,190 (Hwo): and U.S. Pat. No. 4,550,141 (Hoh), the disclosures of which are incorporated herein in their entirety by reference thereto.

[0079] A non-peetabie seal may also be employed e.g. a strong integral heat seal along either a portion or along the entire perimeter. Such a non~peelabie seal may be easily opened by tear open features such as notches, and surface weakened areas, or through the use of tools such as scissors, etc.. The attachment means between (a) the Attorney Docket No. 20808- WO cap, and (b) the tray wall can be formed by a variety of ways, and may be either removable or permanent. Mechanical fasters such as snap fit attachment or press fit fastening means may be provided by mating detents and recesses with either being located on at least one of the cap and the tray wall. Attachment may also be by a permanent seal. For example, the seal may be formed as a weld heat seal by application of heat and pressure to the cap and tray wall with their respective surfaces in contact with each other for a sufficient time to cause bonding with cooling of the bonded perimeter to form an integral permanent seal. Alternatively, an adhesive can be sandwiched between the cap and tray wall.

[00803 As previously mentioned the lid may be heat sealed to the tray. Also, the cap may be attached to the wall portion by heat sealing. Such seals may have a minimum width of about 1 mm to about 5 mm or more. Preferred widths are from 5 to 15 mm with a typical width being about 8-10 mm.

[0081] The seal between the lid and tray wall e.g. at a flange, may be a permanent seal made by use of a heat seal or permanent adhesive or it may also be removable e.g. by using a peelable seal. The lid seal, whether permanent or peeiable, can seal contents within a compartment of a tray with only a small tray wail vent having a gas passageway that filters out unwanted materials such as particles and microbes. Thus, the tray is equipped with a gas sterilization vent in a wall or lid, preferably in its rigid wall, which comprises filter media disposed between a foramsnous cap and a tray wall or lid, and so equipped provides a gas sterilization container and barrier to nongaseous particles including biological agents, pathogens, bacteria, viruses, etc.

[00823 Typical contents for various embodiments of the inventive tray container may include, for example, medical devices, stents, catheters, medical equipment, tools, bandages, surgical supplies, transdermal patches, bandages, wound care products as well as personal care products such as soaps, lotions, skin, nail, and hair care products, cotton balls or swabs, emery boards, contact lenses, hearing aids, identification tags and chips for pets or wildlife, foodstuffs such as spices, herbs, mushrooms, berries, etc. The inventive vented tray may also have applications where rapid venting due to Attorney Docket No. 20808- WO pressure changes is required to equilibrate internal pressure within a package with exterior pressures while achieving or maintaining a barrier to undesirable particles, chemicals, or organisms, etc,

[0083] I will be recognized that many different shapes for both the container tray and its vent and vent components may be employed including vents which are polygons such as hexagons or circular or oval or other curved or linear shapes or combinations thereof may be used.

[0084] In the present invention the distance between gas entrance and exit points of the vent is at ieast equa! to or greater than the thickness of the filter material used. As used herein it wilt be appreciated that it is contemplated that the entrance and exit points will be reversible and flo will typically proceed back and forth e.g. in gas sterilization processes where vacuum is applied and then a sterilant gas pumped in foiiowed by vacuum removal for several iterations followed by flushing cycles of vacuum purging and flushing gas to remove the sterilant gases. An description with respect to entrance and exit should be read to include fiow in the reverse direction unless otherwise specially excluded.

[0085] To illustrate use of the vented gas sterilization tray by a packager or manufacturer of articles to be contained therein, a tray is formed e.g. by thermoforming and assembled with filter media and cap attached to the tray wail e.g. at its base with an opening in the tray wall and an opening in the adjacent cap. An article is piaced into the internal compartment of the tray through its open top which is then covered with a flexible transparent lid which is sealed to the tray sidewa!l flange, for example, by heat sealing thereby forming a sealed ventable package having only a tortuous path gas vent microbial barrier passageway between the exterior and interior thereof .

[0086] In a typical or representative gas sterilization process, a sealed tray

containing an article to be sterilized such as a hip implant is p!aced in a sterilization chamber. The sealed tray has only its filter vent providing a gas passageway between the tray compartment and external environment. The vent serves multiple functions; Attorney Docket No. 20808- WO initially, it provides a means for gas transfer into and out of the compartment so thai the compartment interior and the hip imp!ant may be sterilized, in addition, after completion of sterilization, the vent provides a barrier to and/or filters out undesirable material e.g. particles, dust, bacteria, viruses, pathogens, etc. to permit the implant to be transported, stored and handled prior to use without compromising the implant's sterility. The vented tray also permits the package to shipped or subjected to, or maintained in

environments which have a wide range of pressures or pressure changes without damage to the package caused b pressure differentials between the exterior and interior of the package.

[00873 After introduction of the tray to the gas sterilization chamber, the chamber is closed and the state of the atmosphere around the tray is random air flow with no pressure differential between the interna! compartment and the external environment outside the tray. Airflow through an ingress port and egress port is in equilibrium. Then the sterilization process begins and the ingress port is closed and a vacuum applied to the egress port. Since there are little or no restrictions between the external

environment and egress port gases in the externa! environment air is removed quickly. However, atmospheric gases contained within the interior compartment of tray have no place to go except through the restricted passageway provided by the f ilter media of the vent in the tray wall. Thus, depending upon the venting capability of the vent there will be a tendency for the tray walls and especially its thinner flexible film lid to expand due to a pressure differential that is formed between a low pressure zone in the external environment and a relatively high pressure zone in the interior compartment of the tray. If the pressure differential is too great and/or lasts for too much time, then this

expansion balloons out the tray lid thereby stressing the perimeter sea! which attaches the lid to the tray sidewali flange which may then lead to a weakened seal which may prematurely fail and ultimately result in destruction of the tray package integrity and sterility. The gases within the interna! compartment can only flow out via the filter vent unless the pouch wall ruptures or seals fail and burst open. Attorney Docket No. 20808- WO

[0088] !n the sterilization process, once the chamber and pouch contents have been evacuated, then the pressure is reversed, but with addition of a sterilizing gas which is typically ethylene oxide (ETO) and/or steam. The egress means such as an egress port is closed and ETO and/or steam is admitted e.g. through ingress means such as an ingress port. The process is then repeated for a plurality of cycles depending upon the protocols for sterilization; used by various manufacturers and packagers. Flushing gases such as nitrogen and also elevated humidit may be employed in these

processes. The temperature employed during this process may also be varied to enhance or aid the sterilization process and typically elevated temperatures may be used, but decreased temperatures may also be used as well as a combination thereof. Thus, it may be seen that it is highly desirable to employ filtration vents capable of quickly transporting large volumes of gas to minimize (i) pressure differential magnitude, and (ii) the length of time at a pressure differential. In addition to the stresses placed upon the container walls and seals, the time for the sterilization process is impacted because those stresses may be minimized by slowing the rate of change of the pressure or vacuum applied during the process as a means to avoid undue stress on the container. So if a vacuum is applied slowly i.e. with a slow ramp up in pressure, then more time is afforded to permit the passage of gas across the filter vent and this reduces both the pressure differeniial and stress at the expense of a slower sterilization process. It would be desirable to have a quick process and permit the sterilization equipment to sterilize more containers in a given amount of time,

[0089] In the prior art filter venting is typically provided by a calendared medical grade paper or a calendared spun bonded polyolefin such as that commercially sold under the brand Tyvek®. This spunbonded material is a very good barrier to passage of microbes and particulates, but requires a large surface area to provide sufficient gas flow across its thickness for efficient use in gas sterilization processes. It is also opaque and non-transparent obscuring the view therethrough. Typically the paper or Tyvek® is used as the lid for the tray or constitutes a large portion of the lid. Also, the softening and melting point temperatures for spunbonded polyolefins used in commercial Tyvek® or a heat seal coating applied thereto are such that heat seals to the material are Attorney Docket No. 20808- WO weakened by exposure to steam heat leading to possible premature seal failure

especially under the stresses produced by the inherent air flow restrictions of the material. Also, gas flow transverse to its thickness is inherently blocked by the structure of the commercial material forming an effective barrier to transverse venting. Typical thicknesses of commercially available spun bonded poiyoiefin materials used in sterilizable packaging range from about 6 to 8 mils (152 - 203 μ). Papers are also sometimes used and have a thickness which ranges from 2 to 6 mils (51 - 152 μ). Both papers and spunbonded polyolefins such as Tyvek® have significant resistance to transverse gas flow which is inadequate for any utility in small vent devices such as those enabled by the present invention.

[00903 Returning to the invention, the key parts of the vented tray according to the invention are; (1 ) a filter media, typically greater than 1/16 inch (1587.5 microns) in thickness, preferably in the form of a thin sheet or disc, that combines: (i) good gas flow (not only across its thickness, but transversely along its length and preferably radially in all directions) with (ii) excellent filtration barrier properties (to arrest, impede and bar transfer of undesired materials between the entrance and exit points of the filter media); (2) a foraminous tray wail portion that covers a desired portion of a filter media surface; and (3) a foraminous cap across the thickness of the filter media from the foraminous tray wall portion and having an opening therethrough.

[0091] In a preferred embodiment of the invention, the position of the cap and tray wall portion and their respective openings or holes are such that a longer transit path than the width of the filter media is formed therebetween. This longer transit path mainly extends radially or transversely to the shortest distance across the filter media thickness. In this manner a longer tortuous path may be utilized with a sufficiently open pore structure to preferably both increase gas flow and reduce undesired particle and material transmission between ingress and egress points.

[0092] However, in ali embodiments of the invention including those having holes in the cap and tray wall directly across from one another, a thicker f ilter media than paper Attorney Docket No. 20808- WO or Tyvek€> spunbonded poSyoiefin may be utilized to provide an advantageous combination of high gas flow and excellent filtration barrier properties. Thus, in the present invention, gas may transit either or both (1) across the face of a thicker filter media; and (2) between a defined area of a first face of the filter sheet edge and a transversely displaced defined area on the opposing second face of the filter sheet at a point away from the first defined area and therefore resulting in a change of direction of gas flow from an axial entrance point to an offset exit point thus making at least two right angles or 90° turns in general direction from the typical across thickness flow in prior art packaging. The distances employed by the presently disclosed vent technology range from (i) the thickness of a suitabl filter sheet media as for the "across the face" transit method {1 ) above where typical distances are at least about 0.062 inches, to transit method (2) having offset openings where typical distances may be from 0.125 inches to 0.375 inches or longer. In comparison to the typical

commercially used uncoated and coated Tyvek® thickness which range from about 0.0073 to 0.0078 inches or medical papers which are even thinner in thickness, typically between about 0.0025 and 0.0045 inches, it is seen that these examples of the filter media thicknesses and transit distances according to the invention provide a much greater distance of passage from entrance to exit points. This distance may be e.g. generally about 16 to 48 times greater than the thickness of coated Tyvek® and even greater when compared to the thinner uncoated Tyvek® or medical currently papers used. Thus the present invention creates a device which may produce a Ionger path to intercept or otherwise filter out unwanted materials, microbes, viruses, bacteria, particulates, etc. This path, in preferred embodiments, may also have at least two 90° turns which facilitate filtration by inertia! impaction. 0093J Suitable distance for the gas passageway in the vents of the present invention will be greater than 10 mil (0.010 inch) and typically greater than 50 mi! (0.050 inch), preferably greater than 100 mi! (0.100 inch), more preferably at least 250 mil. As this distance increases a longer tortuous path for filtration is presented with all the advantages presented by greater filtration. Balanced against an increased tortuous path will be the gas flow properties which as described above must be sufficient to Attorney Docket No. 20808- WO withstand the pressure changes to which the package or other article will be subjected. The upper limits may be experimentally determined without undue experimentation based upon other parameters selected Including usage environments e.g. gas sterilization apparatus and processes, transit conditions, and gas flow rates obtainable by different filter media, volumes to be sterilized or held, etc.

[00943 Typically in radial filter vent equipped tray embodiments according to the present invention, this distance will be at least double the distance across the narrow dimension of the filter media {i.e. the thickness). The filtration distance provided by preferred embodiments of the invention which require offset openings in opposing filter vent faces may be from 2, 3, 4, 5, 8, 7, 8, 9, 10 or more times greater in distance than the thickness of the filter media used and over 16 times greater than the thickness of commercially available coated Tyvek®. it may be from 28 to 50 to 83 to 150 times greater than the thicknesses of commercially available papers for gas sterilization packaging.

[0095] In prior art filter vents adapted for use in packaging frays or with lid stock for semi-rigid or rigid containers such as trays, the venting and filtration is always across the thickness of the filter media which is typically thin, being paper or spun bonded polyoiefin and especially that sold under the trademark Tyvek®. Tyvek® is an excellent barrier to transmission of undesired materials such as particulates and micro-organisms such as bacteria and viruses, but provision of this type of material barrier causes gas flow to be restricted. This gas flow restriction is ameliorated by using a sufficiently large area of filter media to reduce pressure differentials induced by expected conditions of use. However, use of large areas of e.g. Tyvek® increases cost and also presents an increase chance that fibers from the spunbonded filter media ma detach and contaminate package contents.

[00963 The present invention fakes a different approach to address these limitations of the prior art. In the present invention, a filter media having an open pored three dimensional tortuous path structure may be utilized with tray walls and lids having low gas permeability, and which also are barriers to other materials including particulates, Attorney Docket No. 20808- WO organisms, bacteria, viruses, etc., to direct the fiow of gases aiong a longer path than the thickness of a thin sheet material, !n this manner several improvements and advantages over the prior art are enabled.

[0097] ^^rst _> possibility of contact between the contents and the filter media is reduced because a non-fibrous lid, cap, and tray wail may cover most of the package interior and employing a smaller filter media surface. These iid, cap, and wall components may be selected to be inert with respect to the package contents and act as a barrier to any other undesired material such as micro-organisms, bacteria, viruses, particulates, dust, etc., Advantageously, it may also be selected to present a smooth, nonabrasive surface which is unlikely to contaminate the contents e.g. by detached or abraded fibers or particles from a coating.

[0098] Second, a longer tortuous path may be used to provide excellent filtration while utilizing increased pore sizes. By appropriate selection of filter media and in conjunction with the tray wall, cap and lid, gases are directed over a longer path and preferably lengthwise and radially from a line representing the shortest distance across the filter media thickness. By increasing the distance, filtration capability may be maintained or even improved while at the same time Increasing pore size or

passageway clearance; and this can be done while keeping a low profile along the package wall which minimizes the projection of the vent into the package interior. Thus the thickness of the vent is kept small, typicaliy sizes under 125 mils (3.2 mm) in thickness, and preferably from about 60 to 125 mils (15-3.2 mm). Depending upon the application the filter media sheet thickness may range as thin as is consistent with the volume of gas and gas flow rate that is needed for conditions of use. It is contemplated that thicknesses as low as 100 microns will be suitable. Of course larger thicknesses than 125 mil could be employed, but typically there will be no offsetting advantage to do so. By keeping the thickness low to provide a thin vent, the vent will not interfere with the tray contents, content loading and removal with be unhindered and there will be less likelihood of abrasion or detachment by frictional forces. Also, more trays may be held within a given unit space. Preferably, the distance from the perimeter of the section Attorney Docket No. 20808- WO containing the openings in the cap and the perimeter of the section containing the openings in the foraminous tray wail portion is greater than the filter thickness between the cap and tray wall portion. This increase in gas passageway by providing a iaterai path does not come at the expense of increased filter sheet sizes since the prior art commercial calendared paper and spun bonded polyoleftn sheets already require a larger Iaterai area due to vent flow rate limitations inherent in those materials.

[00993 Third, air flow rates are greatly improved by provision of filtration media that have larger pore sizes or gas passageway clearance, without sacrificing material , particulate and micro-organism filtration capabilities. The present invention utilizes three dimensional gas flow provided by open celled materials such as sintered open celled polymers and an open celled foamed polymers and plastics,

[00100] Fourth, a transparent lid may be employed to provide an unobstructed view of the tray contents. A transparent lid may also be combined with a transparent tray and/or insert.

[00101] Thus, the present invention may see an improvement in one or more of the above properties. Preferred embodiments of the invention will have a combination of improved properties. The inventive vented tray may increase air flow rates while maintaining or increasing filtration against passage of unwanted materials while providing a protective filter cover on the package interior and do this in a smaller space and using less material than presently employed in commercial packaging e.g. for medical devices and suppiies.

[00102] The present invention in its various embodiments finds particular utility in providing packaging for a product which undergoes gas sterilization such as a medical device such as an implantable joint, catheter etc. , or for personal care items such as cotton swabs, cosmetics, etc., or for foodstuffs such as spices, mushrooms, or berries, etc. Attorney Docket No. 20808- WO

[00103] The above-described features of the invention in its various embodiments illustrate that a variety of shapes, sizes and configurations may be employed in the present invention,

[00104] Advantageously, the present invention permits smaller sized filter vents to be used at a materia! cost savings while maintaining and enhancing protection of enclosed products from damage and contamination during transportation through zones of pressure differentials such as those found in gas sterilization operations, !t also provides enhanced visibilit to tray contents.

Embodiments of the inventions

1. A vented rigid tray for gas sterilization comprising:

(a) a synthetic po!ymer tray wall having an exterior surface and an interior surface and comprising a base and upstanding base sidewai!, with a foraminous wall portion in at least one of the base and the sidewal!;

(b) fi!ter media;

(c) a foraminous cap; and

(d) attachment means for the foraminous cap and the tray wall whereby the filter media is held between the cap and the foraminous wall portion e.g. by snap fit or press fit mechanical fastening, adhesives, heat seals, ultrasonic welding, or combinations thereof.

2. A rigid tray, as defined in embodiments 1-39, wherein the foraminous wa!l portion is in the base.

3. A rigid tray, as defined in embodiments 1-39, wherein the base sidewa!i has a heat sealable lid receiving flange.

4. A rigid tray, as defined in embodiments 1-39, wherein the cap has a panel and a continuous sidewaSi depending therefrom. Attorney Docket No. 20808- WO

5. A rigid tray, as defined in embodiments 1-39, wherein the tray is thermoplastic or thermosetting.

6. A rigid tray, as defined in embodiments 1-39, wherein the iray is transparent.

7. A rigid tray, as defined in embodiments 1-39, wherein the tray wall is thernioformed or injection molded.

8. A rigid tray, as defined in embodiments 1-39, wherein the foraminous wall portion has a continuous projecting wali proximate to and surrounding the portion.

9. A rigid tray, as defined in embodiments 8-39, wherein the projecting wall extends from the tray wall towards the tray exterior.

10. A rigid tray, as defined in embodiments 8-39, wherein the projecting wall extends from the tray wail towards the tray interior.

1 . A rigid tray, as defined in embodiments 8-39, wherein the cap has a panel and a continuous sidewall depending therefrom with the cap sidewall having at least one detent which cooperates with the projecting wall to provide the snap fit attachment means and optionally the cap may be formed of a foraminous material such as sintered porous polyolefin forming a cap which functions as a filter itself.

12. A rigid fray, as defined in embodiments 8-39, wherein the cap is provided with at least one detent and the projecting wall has at least one recess, each the detent and recess are adapted to cooperate to provide the attachment means whereby the cap is securely connected to the tray wail.

13. A rigid tray, as defined in embodiments 8-39, wherein (i) the wall portion has one or more openings (A) therethrough in a first section within an interior space defined by the projecting wall and has no openings within a second section which is also within the interior space defined by the projecting wali; and (ii) the cap has a panel and a Attorney Docket No. 20808- WO continuous sidewaSI depending therefrom and has one or more openings (8) through the panel in a first section within an interior space defined by the continuous sidewall and has no openings within a second section which is also within the interior space defined by the continuous sidewall; and (iii) wherein the cap is secured to the wall portion with the first and second cap sections oriented with respect to the first and second wail portion sections such that a path from openings A to openings B in its shortest distance D_R is greater than a path from an interior surface of the cap pane! to an interior surface of the wall portion circumscribed by the projecting wall in its shortest distance D .

14. A rigid tray, as defined in embodiments 13-39, wherein D_R≥ 2D_T .

15. A rigid tray, as defined in embodiments 13-39, wherein the cap and the tray wail have orienting means for positioning the openings 8 in a spaced apart relationship, along a plane of the cap pane!, to openings A.

16. A rigid tray, as defined in embodiments 15-39, wherein the orienting means

comprise at least one of; (i) mating cap and wall portion projecting wail

configurations which preclude transverse alignment of openings A and B, (ii) locating notches or visual indicators in the cap and wall portion, (iii) an asymmetric cap perimeter, and (iv) positioning lock tabs.

17. A rigid tray, as defined in embodiments 1 -39, further comprising an article located within an interior surface of the tray and a transparent iid attached to the sidewall by a continuous seal.

18. A rigid tray, as defined in embodiments 17-39, wherein the sea! is a tamper evident heat seal.

19. A rigid tray, as defined in embodiments 1 -39 wherein a transparent iid provides an unobstructed view of an enclosed article. Attorney Docket No. 20808- WO

20. A rigid iray, as defined in embodiments 19-39, wherein the article is a medicai

device, a pharmaceutical product, a personal care product or a foodstuff.

21. A rigid tray, as defined in embodimenis 1-39, wherein the filter media comprises: air Said, wet laid or dry Said nonwovens; polypropylene, polyethylene, polyester, nylon, cellulose fibers or permeable sheets; cotton; sintered porous polymers; open ceiled foamed polymers; woven fabrics, carded materials, meitblown webs, spunbonded webs, nanofiber webs, microporous films, paper, fiberglass, unbonded synthetic fibers, or combinations thereof.

22. A rigid tray, as defined in embodimenis 1 -39, wherein the synthetic polymer tray wail comprises a mono! a er or multilayer structure.

23. A rigid tray, as defined in embodiments 1-39, wherein the synthetic polymer tray wail comprises a po!yo!efin. polyester, poiyureihane, polystyrene, cyclic olefin copolymer, a porous sintered polymer, or combinations thereof.

24. A rigid iray, as defined in embodiments 1-39, wherein the syntheiic polymer tray wail comprises a polyester terephthalate (PET) homopo!ymer or copolymer, amorphous PET (aPET), glycol modified PET (PETg), high impact polystyrene (H!PS), high density polyethylene (HOPE), polypropylene or combinations thereof.

25. A rigid tray, as defined in embodiments 1-39, wherein the synthetic polymer tray wail comprises a multilayer structure having at least one layer of polyester terephthalate (PET) homopolymer or copolymer, and an interior surface layer comprising poiyureihane.

26. A rigid tray, as defined in embodiments 1-39, wherein the synthetic polymer tray wail comprises a multilayer structure having an interior surface layer comprising poiyureihane or a cyclic olefin copolymer.

27. A rigid iray, as defined in embodimenis 1-39, wherein ihe synthetic polymer tray wall has a thickness between 20 to 60 mil (508-1524 microns). Attorney Docket No. 20808- WO

28. A rigid tray, as defined in embodiments 1-39, wherein the filter media is greater than 10 mil (254 μ) in thickness.

29. A rigid tray, a defined in embodiments 1-39, wherein the fitter media is greater than 100 mil (2540 u) in thickness.

30. A rigid tray, as defined in embodimenis 1 -39, wherein the filter media has a gas path distance greater than a minimum thickness of the filter media.

31. A rigid tray, as defined in embodiments 1 -39, wherein the gas path is at least 10 mil (254 μ) in length, preferably at least 100 mii (2540 μ), and more preferably at least 200 mil (5080 μ).

32. A rigid tray, as defined in embodiments 1-39, wherein the fitter media has a three dimensional open ceil structure.

33. A rigid tray, as defined in embodiments 1 -39, wherein the filter media comprises a sintered porous polyolefin and optionally the filter media comprises the foraminous cap.

34. A rigid tray, as defined in embodiments 1-39, wherein the filter media comprises an open celled foamed polymer.

35. A rigid tray, as defined in embodiments 1-39, wherein the filter media comprises a fibrous polypropylene mat.

36. A rigid tray, as defined in embodiments 1 -39, wherein the filter media comprises a sintered porous polyethylene,

37. A rigid tray, as defined in embodiments 1 -39, wherein the filter media has a pore size between 1 -500 microns with pores extending in three dimensions. Attorney Docket No. 20808- WO

38. A rigid tray, as defined in embodiments 1-39, wherein the fitter media has a pore size between 15-50 microns.

39. A rigid tray, as defined in embodiments 1-39, wherein the filter media further

comprises an anti-microbiai agent

[00105] Various embodiments have been described above. Although the invention has been described with reference to these specific embodiments, the descriptions are intended to be illustrative and are not intended to be limiting. Various modifications and applications may occur to those skilled in the art without departing from the true spirit and scope of the invention as defined in the appended claims.

[001 6] What is claimed is:

Claims

Attorney Docket No. 20808- WO

1. A vented rigid tray for gas sterilization comprising:

(a) a synthetic polymer tray wall having an exterior surface and an interior surface and comprising a base and upstanding base sidewaii, with a foraminous wall portion in at least one of said base and said sidewaii;

(b) filter media;

(c) a foraminous cap: and

(d) snap fit attachment means for said foraminous cap and said tray wail whereby said filter media is held between said cap and said foraminous wail portion.

2. A rigid tray, as defined in ciaim 1 , wherein said foraminous wail portion is in said base,

3. A rigid tray, as defined in claim 1 , wherein said bas sidewaii has a heat seaiab!e lid receiving flange,

4. A rigid tray, as defined in claim 1 , wherein said cap has a panel and a continuous sidewaii depending therefrom.

5. A rigid tray, as defined in ciaim 1 , wherein said tray is thermoplastic or thermosetting.

6. A rigid tray, as defined in ciaim 1 , wherein said tray is transparent.

7. A rigid tray, as defined in claim 1 , wherein said tray wall is thermoformed or injection molded.

8. A rigid tray, as defined in claim 1 , wherein said foraminous wall portion has a

continuous projecting wall proximate to and surrounding said portion. Attorney Docket No. 20808- WO

9. A rigid tray, as defined in claim 8, wherein said projecting wail extends from said tray wall towards said tray exterior.

10. A rigid tray, as defined in claim 8, wherein said projecting wail extends from said tray wail towards said tray interior,

1 1 . A rigid tray, as defined in claim 8, wherein said cap has a panel and a continuous sidewali depending therefrom with said cap sidewail having at least one detent which cooperates with said projecting wall to provide said snap fit attachment means.

12. A rigid tray, as defined in claim 8, wherein said cap is provided with at least one detent and said projecting wall has at least one recess, each said detent and recess are adapted to cooperate to provide said attachment means whereby said cap is securely connected to said tray wail.

13. A rigid tray, as defined in claim 8, wherein (i) said wail portion has one or more

openings (A) therethrough in a first section within an interior space defined b said projecting wall and has no openings within a second section which is aiso within said interior space defined by said projecting wail; and (is) said cap has a pane! and a continuous sidewail depending therefrom and has one or more openings (B) through said panel in a first section within an interior space defined b said continuous sidewail and has no openings within a second section which is also within said interior space defined by said continuous sidewail; and {Hi) wherein said cap is secured to said wali portion with said first and second cap sections oriented with respect to said first and second wall portion sections such that a path from openings A to openings B in its shortest distance O is greater than a path from an interior surface of said cap pane! to an interior surface of said wall portion

circumscribed by said projecting wail in its shortest distance DT.

14. A rigid tray, as defined in claim 13, wherein D ≥ 2D . Attorney Docket No. 20808- WO

16. A rigid tray, as defined in claim 13, wherein said cap and said tray wail have

orienting means for positioning said openings B in a spaced apart relationship, along a plane of said cap panel, to openings A.

16. A rigid tray, as defined in claim 15. wherein said orienting means comprise at least one of: (i) mating cap and wall portion projecting waff configurations which preclude transverse alignment of openings A and B, (ii) locating notches or visual indicators in said cap and wall portion, (iii) an asymmetric cap perimeter, and (iv) positioning Sock tabs.

17. A rigid tray, as defined in claim 1 , further comprising an article located within an

interior surface of said tray and a transparent !id attached to said sidewali by a continuous sea!.

18. A rigid tray, as defined in claim 17, wherein said sea! is a tamper evident heat sea!.

1 . A rigid tray, as defined in claim 17 wherein said transparent iid provides an

unobstructed view of said article.

20. A rigid tray, as defined In claim 17, wherein said article is a medical device, a

pharmaceutical product, a personal care product or a foodstuff.

21. A rigid tray, as defined in claim 1 , wherein said filter media comprises: air laid, wet Said or dry laid nonwovens; polypropylene, polyethylene, polyester, nylon, cellulose fibers or permeable sheets; cotton; sintered porous polymers; open ceiled foamed po!ymers; woven fabrics, carded materials, meltblown webs, spunbonded webs, nanofiber webs, microporous films, paper, fiberglass, unbonded synthetic fibers, or combinations thereof.

22. A rigid tray, as defined in claim 1 , wherein said synthetic polymer tray wall comprises a monolayer or multilayer structure. Attorney Docket No. 20808- WO

23. A rigid tray, as defined in claim 1 , wherein said synthetic poiymer tray wall comprises a polyolefin, polyester, poiyurethane, polystyrene, cyclic olefin copolymer, or combinations thereof.

24. A rigid tray, as defined in claim 1 , wherein said synthetic poiymer tray wall comprises a polyester terephthalate (PET) homopoiymer or copolymer, amorphous PET (aPET), glycol modified PET (PETg), high impact polystyrene (HIPS), high density polyethylene (HOPE), polypropylene or combinations thereof.

25. A rigid tray, as defined in claim 1 , wherein said synthetic polymer tray wall comprises a multilayer structure having at least one layer of polyester terephthalate (PET) homopolymer or copolymer, and an interior surface layer comprising poiyurethane.

26. A rigid tray, as defined in claim 1 , wherein said synthetic polymer tray wall comprises a multilayer structure having an interior surface layer comprising poiyurethane or a cyciic olefin copolymer.

27. A rigid tray, as defined in claim 1 , wherein said synthetic polymer tray wall has a thickness between 508 to 1524 microns.

28. A rigid tray, as defined in claim 1 , wherein said filter media has a thickness Dj of at least 62 mil (1575 microns).

29. A rigid tray, as defined in claim 1 , wherein said filter media has a thickness Dr of at least 125 mil (3175 microns),

30. A rigid tray, as defined in claim 13, wherein D ≥ 125 mil (3175 microns).

31. A spring cover comprising:

resilient thermoplastic filtration substrate of porous sintered poiymer and fastening means for connecting said cover to a polymeric tray were said means are selected from the group of mechanica! fasteners, adhesives, heat sea!abte materials.

5 i Attorney Docket No. 20808- WO

32. A spring cover, as defined in claim 31 , wherein said fastening means comprises a distortable cover perimeter adapted for compression or extension for manual positioning and mechanical engagement with a tray wail.