CA2182353A1 - Absorbent packet - Google Patents
Absorbent packetInfo
- Publication number
- CA2182353A1 CA2182353A1 CA 2182353 CA2182353A CA2182353A1 CA 2182353 A1 CA2182353 A1 CA 2182353A1 CA 2182353 CA2182353 CA 2182353 CA 2182353 A CA2182353 A CA 2182353A CA 2182353 A1 CA2182353 A1 CA 2182353A1
- Authority
- CA
- Canada
- Prior art keywords
- absorbent
- film
- packet
- absorbent packet
- gas permeable
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
- B65D81/24—Adaptations for preventing deterioration or decay of contents; Applications to the container or packaging material of food preservatives, fungicides, pesticides or animal repellants
- B65D81/26—Adaptations for preventing deterioration or decay of contents; Applications to the container or packaging material of food preservatives, fungicides, pesticides or animal repellants with provision for draining away, or absorbing, or removing by ventilation, fluids, e.g. exuded by contents; Applications of corrosion inhibitors or desiccators
- B65D81/266—Adaptations for preventing deterioration or decay of contents; Applications to the container or packaging material of food preservatives, fungicides, pesticides or animal repellants with provision for draining away, or absorbing, or removing by ventilation, fluids, e.g. exuded by contents; Applications of corrosion inhibitors or desiccators for absorbing gases, e.g. oxygen absorbers or desiccants
- B65D81/268—Adaptations for preventing deterioration or decay of contents; Applications to the container or packaging material of food preservatives, fungicides, pesticides or animal repellants with provision for draining away, or absorbing, or removing by ventilation, fluids, e.g. exuded by contents; Applications of corrosion inhibitors or desiccators for absorbing gases, e.g. oxygen absorbers or desiccants the absorber being enclosed in a small pack, e.g. bag, included in the package
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/26—Drying gases or vapours
- B01D53/261—Drying gases or vapours by adsorption
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W90/00—Enabling technologies or technologies with a potential or indirect contribution to greenhouse gas [GHG] emissions mitigation
- Y02W90/10—Bio-packaging, e.g. packing containers made from renewable resources or bio-plastics
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S428/00—Stock material or miscellaneous articles
- Y10S428/913—Material designed to be responsive to temperature, light, moisture
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
- Y10T428/131—Glass, ceramic, or sintered, fused, fired, or calcined metal oxide or metal carbide containing [e.g., porcelain, brick, cement, etc.]
- Y10T428/1317—Multilayer [continuous layer]
- Y10T428/1321—Polymer or resin containing [i.e., natural or synthetic]
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
- Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
- Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
- Y10T428/1362—Textile, fabric, cloth, or pile containing [e.g., web, net, woven, knitted, mesh, nonwoven, matted, etc.]
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/23—Sheet including cover or casing
- Y10T428/239—Complete cover or casing
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249967—Inorganic matrix in void-containing component
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249978—Voids specified as micro
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249987—With nonvoid component of specified composition
- Y10T428/24999—Inorganic
Abstract
An absorbent packet for absorbing water vapor. The absorbent packet comprises a gas permeable, multi-layered packaging material which absorbs water vapor, but does not permit liquid water within the packet from flowing back through the packaging material, wherein the packaging material preferably comprises a microporous film, a gas permeable film and a binder to bind the microporous film to the gas permeable film, and an absorbent material incorporated between the layers of the multi-layered packaging material. This absorbent packet is particularly useful for absorbing water vapor in shipping containers where changes in the atmospheric condition result in variable relative humidity in the shipping container.
Description
2 1~2~ 7U~J UU~
( a ) Title of Invention A13SORBENT PAC~ET
( b ) Backqround of Invention --1. Field of Invention.
This invention relates to absorbent products. More sper;firAlly, this invention is an absorbent packet for use within ~hirrin~ containers for AhQnrh;n~ water vapor.
2. Prior Art.
Packets containing AhQnrhP~t and ~lp~irrAnt materials have been available for many years. The absorbent and ~lPQ-ircAnt materials are intended to absorb moisture and prevent that moisture from adversely affecting both the packets in which the absorbent or rcAnt ~tPriAlQ are rnntAinP~ and products shipped in shipping containers in which such packets are placed.
It is also well known that liquid water present in metal Qhirrinq containers can cauge rusting. The likPlihnod that these Qhirrin~ containers will rust increases if the Qhirrin~ containers are used to store products over great distances for long periods of time. For example, commercial food products are often transported in shipping containers for weeks at a time on container ships.
Often during the time the products are being shipped, the shipping containers are subjected to a variety of atmospheric conditions, inrlll~linq gituations where high hum~dity is present. Because of the si~n;firAnt amount of time n~cessAry for such long distance Qhirrin~ and the re8ulting long term exposure of the shipping containers and the products within those shipping containers to water and water vapor cau3ed by the high humidity in the atmosphere, a si~n;ficAnt rusting problem in thege Rh;rping containers now exists. This problem adversely affects not only the Rh;rrin~ containerg, but also the ~rkA~in~ for the shipped products, the products themselves and r-~hinPry utilized with the Qh i rri n~ containers .
Thus, reliable products are needed to control the relative humidity within such shipping containers for the long period of shipping. In addition, once water vapor has been Ahcnrhed into a packet, it is important that the water vapor not be released back into the Rh;rrinq container in the form of liquid water, even if the high humidity conditions continue. Such release increases the likPlih~od of rugting of the Rhirrin~ containers and the associated r-~hi nPry.
The concept of utilizing deqi ~ ~Ants or AhsorhDnt products to remove moisture from the air in ~ ju~ ion with vapor corrosion inhibitors i8 known in the art. For example, U.S. Patent Number 5,324,448 discloses a ti~Rif - Ant f~orlfAinPr which also contains vapor corrosion inhibitor. The rac~kA~in~ material for this product is a spun-bonded olefin, preferably a spun-bonded polyethylene, marketed as TYVER, a registered trademark of the DuPont de Nemours Company.
See also U.S. Patent Number 5,391,322.
Another water absorbing product is disclosed in U . S . Patent Number 5,148,613. This product is a closet drier, containing a deqi~ rAnt material for Ah5~rhin~ moisture. The pA~kA~in~ of the cover for this container is also a spun-bonded polyolefin, pref erably TYVEK~ .
~
U.S. Patent ~umber 4,856,649 discloses a deodorizer parcel wherein the structure of the parcel body is a composite material formed from a gas pl~ -hl e sheet, such as a sheet of paper or a non-woven cloth, and a plastic film, such as a polypropylene film, laminated on and bonded to the gas p ~hl e sheet. The plastic film has a multiplicity of minute pores formed by subjecting the film to irradiation with a laser beam.
U.S. Patent No. 3,745,057 discloses a 5t~rili7~h]~ package and ci~qirc~nt product wherein the film forming the cover for the package is an open-celled mi-:Lu~UlUUs film. The microporous film is formed by a process of sequential cold stretching and hot 3tretching the f ilm to impart the open-celled structure to the mi.;Lu~orous film.
Other liquid absorbing and i ~~~i7i7in~ packets are disclosed by U.S. Patent Numbers 4,748,069 and 4,749,600. The packaging for these products is a c~ ' inzltit-n of starch paper and polyvinyl acetate, which r~-k~in~ dissolves in water. See also U.S. Patent Number 4, 853, 266 .
A number of absorbent packets have also been ~li q~l oq~-d which are utilized for the shipping of hazardous liquids wherein the pArk~in~ material for those products includes an ~hsorh~nt product. ~lowever, the outside layer of the r~k~i n~ for these products is required to be i -hl e to water vapor. See, for example, U.S. Patent Number 4,969,750 and 4,927,010.
Finally, there have been a number of ~hs~rh~nt pad products which are used with food products to absorb fluids from the food.
~he FA~ Ag; ng material for these products is generally formed from a sandwich-type structure containing a liquid p ~hl e layer on one side, a liquid ; - - -hl e layer on the opposite side and a fluid absorbent inner layer between the liquid p~ --hle and - -hle layers. See, for example, U.S. Patent ~umber 4,756,939 and 4,802,574. Because the goal of these products is to absorb liquid discharge from food, liquid p,~ --h; 1 ;ty of the outside layer ia critical to these products.
While a number of these productg are useful in Ahfiorh; n~
liquids and water vapor, there is still a need for; ~v-:d absorbent products, especially Ah5r~rh-~nt packets for use in $;h;rrin~ containers to ~-;ntA;n a constant relative humidity within the container. It is critical that these Ah~)rh~nt packet3 be able to absorb large quantities of water vapor while at the same time not permit liquid water, which may form inside of the Ah~orh-~nt packet, from permeating back into the buLL~ullding environment. In addition, it is important that these absorbent packets be able to maintain relative humidity within a ~h;rr;n~ container for long periods of time regardless of changes in humidity and temperature.
In addition, it is important that these absorbent products be low cost and easy to manufacture.
Accordingly it is the object of this invention to prepare an absoLLalll packet for absorbing water vapor.
It is a further object of this invention to prepare an absorbent packet for use in ~h;rp;n~ containers which will absorb water vapor, but not permit liquid water which may form inside the packet from permeating out from the absorbent packet.
It is a still further object of this invention to prepare a low cost absorbent packet which is comprised of a multi-layered, liquid imp~ --hl~ r~k~in~ material with a mi.:Lupulous~ gas r~ -hl ~ outer layer and a gas p~ -hl ~ inner layer.
It is a still further object of this invention to produce an absorbent packet which uses as the absorbing material a combination of an alkaline earth metal salt and a clay or starch product.
It is a still further object of this invention to produce an Ah~3nrh~nt packet which not only absorbs water vapor, but maintains relative humidity within a ~hirrin~ container for long periods of time .
These and other aspects of the invention will become apparent to those skilled in the art from a cnn~ prAtion of the following d~Ailed description, drawings and claims. The description provides a selected example of construction of the device to illustrate the invention.
(c) SummarY of Invention In accordance with the present invention there i~ provided an absorbent packet for absorbing water vapor for use in a shipping container comprising (a) a gas p~ -hlR, liquid i ,- ~hle packaging material, and (b) an Ah50rhent material contained within the multi-layered packaging material.
~ r~ferab~y the ~b~orberlt n~ erial i9 = ixture of calci~m~
chloride and clay or starch. Preferably the packaging material is a multi-layer material comprised of (1) a microporous, gas pP --hle film, (2) a gas permeable, support film, and ( 3 ) a blnder to bind the microporous f ilm to the gas permeable film.
(d) Detailed DescriPtion of the Preferred Embodimer~ts Although the invention is adaptable to a wide variety of uses, it is; ' ';Pd in an absorbent packet for Ahsf)rh;n~ water vapor in a shipping container ,- ~ ~;n~ a gas ~f --hle~ liquid impermeable pA~k:~;ng material, which abgorbs water vapor but does not permit liquid water which may form within the packet from leaking out of the rA~kA~;n~ material. Preferably the rArkA~;n~ material is a multi-layered rA~-kA~in~ material comprised of a microporous, gas pp- --hlp film, a gas pf --hle support film and a binder to bind the miuLv~vLvus film to the gas p~ ~hle film. Once the rA~kA~;ng film material is formed, an absorbent material, preferably comprised of calcium ~~hl or; rl~ and a clay or starch product, is introduced between layers of the material to form a packet and then the edges of the packet are sealed to produce the absorbent packet.
When a multi-layered packaging material is used as r7P~ -r; hod above, the mi~:LV~oIUU13 film is preferably an open-celled mi.:Lvpolvus film. Microporous films are g~n~rAl ly classified in two types: closed celled films, wherein the pores of the film are not interconnected, and open-celled film, wherein the pores are essentially interconnected through tortuous paths which may extend from one exterior surface or surface region to the opposite surface region. The open-celled microporous film of this invention may be formed by a number of different processes, ;n~ Aing~ for example, cold stretching, i.e. cold drawing the elastic film until porous surface regions or areas, which are elongated normally, and hot stretching, i.e. hot drawing, wherein the film is stretched a~ter forming at a higher temperature to form the microporous product, and then heating or heat setting the porous f ilm under tension or a combination thereof. In addition, other processes can be used, for example, forming the film and then subjecting it to processes which result in microporosity, such as by subjecting it to a laser beam (as taught in U.S. Patent Number 4,856,649) or ~hf~mirAl action .
In a preferred; ~ -riir L, however, the microporous film is a mi-:Lv~Lvus polypropylene sheet containing a calcium carbonate filler. In the preferred process for forming this film, a polypropylene powder i5 mixed with the calcium carbonate filler along with certain additives, such as plasticizers and ;~ntio~ nt8. The polypropylene powder preferably ~ about 30-50% of the mixture by weight with the calcium carbonate ri~in~ preferably about 70-50%, and the additives, preferably about 1-5 % . The polypropylene powder mixture is then extruded using conventional extruding procedures at a temperature of about 200~C - 300~C to form pellets which are then subjected to a film extru~ion procedure at a temperature of about 200~C - 300~C to form n b=~e =heet. ~hi, ~he~t i/~ th~n ~tretnhed in bnth ~ lnngitudi=a1 direction and a transverse direction to f orm the micropOrouG
polypropylene sheet. The calcium carbonate filler within the polypropylene sheet assists in the formation of these micropores by partially filling the pores during the formation process. A
substantial portion of the calcium cArhonAte remains in the film after stretching, comprising as much as about 7096 of the film by weight. The fh;rknP~s of the film is from about 0.01 to 0.20 mm and preferably from 0.02 to 0.15 mm. The micropores are preferably about 1 micron in size. The preferred process for production of this film is disclosed in Nago, et al. "Structure of Ni~;Lu~oL~ u~
Polypropylene Sheets Containing CaC09 Filler", Journal of A~plied Polvmer Science, Vol. 45, pp. 1527-1535 (1992) and NA1 ~r et al.
oL.us Polypropylene Sheets Containing CaC03 Filler", Journal of Applied PolYmer Science, Vol. 49, pp. 143-150 (1993).
The gas pf -hl e film which form3 the second layer of the preferred multi-layered pA~'kA~in~ r-tPr;Al can be prepared from any conventional olP~ini~ plastic film, paper sheet or nonwoven cloth which is gas p -hle. It is critical that this film be both gas pP -hlP and water; -- --hlP and have sllffi~iPnt strength to support the mi~ ololls film layer. Preferably, this gas ~ ~hle film is yIoduc:ed from n.,l- ~ J~ polyester and/or polypropylene fibers formed into a non-woven cloth. Thi3 gas p -hle film is preferably a dry-type, wet-type or spun-bond, non-woven cloth, with the more preferred material being manufactured by Takuso under the name GDT-2 or TYVEK~ manufactured by DuPont. This film preferably weighs between about 10 and 400 g/m2, preferably between 20 and 200 g/m2, has a porosity in Gurley seconds from about 2 to about 50 3econds and a thi~-knP1;s from about 0.05 to about 0.2 mm.
In order to provide additional strength for the packaging material, these two films are bound together, preferably by an adhesive. Any conventional adhe3ive is acceptable which doe3 not interfere with the ga3 p -hility of the compo3ite film. Thu3, it is critical that the adhesive layer between the3e two layer3 not be applied too thickly or cover too much of the 3urface of either of the two films 30 a3 to prevent the pa33age of water vapor through both layer3. Accordingly, preferably the adhe3ive material i3 placed between the layer3 in a (1; ~ nnPcted or discontinuou3 pattern wherein the area3 of adhe3ive material are 3eparated by non-coated area3, for example, in a grid-like 3tructure or a regular dot 3tructure a3 di3clo3ed, for example, in U.S. Patent No.
4,725,465. For example, a me3h-like 3tructure may be utilized, wherein the open 3pace between the me3h i3 at lea3t from about .05 micron3 to about 3 micron3. Alternatively, individual dot3 of adhe3ive can be placed between the layers, wherein the dots are about 1 micron in diameter and 3eparated f rom each other by about to 5 micron3 . Pref erably at lea3t about 4 0 percent of each f ilm remain3 ull~vve~ed by the adhe3ive. In a preferred ' -'i 1 the adhe3ive material is a polyurethane prepolymer solution manufactured under the name Unoflex J-3, by Sanyo ChPrnic~
Industries, Ltd.
The overall thi~knP~s of the preferred multi-layered packaging material is about 0.1 to about l.0 mm., preferably about 0.1 to '~ 2 1 82353 about 0 . 3 mm.
The absorbent material which is introduced into the absorbent packet can be any absorbing material with an PnhAnrPd capacity to absorb water vapor and which is also relatively low in cost.
Preferably, the material should be able to absorb an amount of water up to at least about 509~ of the dry weight of the absorbent material. The preferred absorbing material should exhibit high ab60rbing capacity f or water vapor in ambient air conditions over long periods of time. The types of absorption materials that can be used include those commonly utilized in water absorbing products, such as an alkali-metal polyacrylate or an AlkAlinp-metal partial salt of a cross linked poly (propenoic acid), such as a sodium or potas3ium polyacrylate or a partial sodium salt of poly (propenoic acid). Alternatively, and preferably, the absorption material is a c~ ' ;nAt;on of an inorganic AlkAl;nP earth salt, such as calcium chloride mixed with a clay or starch product. The calcium chloride is mixed with the clay or starch at a ratio f rom about 1 to 9 to about 3 to 7 and preferably from about 1 to 4 to about 1 to 1.
The clay mineral that may be used as an element of the absorbent product is preferably a smectite-type clay, especially an AlkAl ;nP earth 8mectite guch as calcium smectite, with a water uptake capacity ( in termg of the dried smectite with a residual water content of about 6 weight percent) of at least about 5096, preferably about 60 to 130~, more preferably about 90 to 12096.
Alternatively, the smectite may be a sodium Al k~l i nP smectite 2 1 ~2353 containing prf~l inqntly sodium ions as the rerlA~Ahle cations and exhibiting a water uptake capacity of at least about 5096 (with a residual water content of about 6 weight percent). Alternatively, a v~rmic~ll ite or filler material such as wood fiber, paper pulp or other water absorbing materials can be used to replace a portion of the clay material.
If instead a starch product is used, pre~erably it is a potato starch with an absorption capacity of about 10-12 mls of water per gram of starch material. Preferable material is a potato starch produced by Avebe in Veendam, Holland.
In the process for the preparation of this Ahs~rhAnt packet, the multi-layered, gas pP -~hl~ rA~kA~in~ material is first formed. In the formation of this gas ~- ~hl~, liquid i ~hle multi-layered pA~knging ~-t~ri~l ~ the miuLu~uLuua film, preferably a microporous polypropylene sheet material containing calcium carbonate, is prepared using the process as disclosed in ~ago, et al. "Structure of ~licroporous Polypropylene Sheets Containing CaC03 Filler", Journal of Al~plied Polymer Science, Vol. 45, pp. 1527-1535 (1992). Once this mi~:Lo~,Lvus polypropylene sheet is prepared, the gas p~ h~ e film of the type previously di3cussed is then prepared. The miuLu~uL~us film is then bound to the gas p~ -hle film by use of the adhesive material previously discussed. The adhesive should be applied 80 as to leave a si~nifi.-Ant portion of the surface of the composite film uncovered, thus allowing water vapor to pass through both layers. Preferably the gas p~ -qhle~
mi~:Lu~ùL~ s film is formed as the inner layer of the composite .
packaging material and the support ~ilm forms the outer layer of the composite material.
Once the multi-layered r~ork~ing material is formed, a continuous Ahsnrh~nt packet forming procedure is preferably used wherein the AhE~orh~ont material i6 placed between two sheets of the gas p~ -ohle~ multi-layered rn~kA~in~ material and the edges of the sheets are sealed, preferably by heat sealing. Alternatively, a single sheet of the composite, gas r~ -hl.~, liquid i -- ~hle sheet is produced and is folded over on itself after incorporation of the Ahsnrh~nt material into the packet. The 1~ i n; ng edges of the sheet are sealed, preferably heat sealed, to ~-nrnr~-llAte the absorbent material. The amount of the absorbent material llt;l;~ed in the nhsn 1 _ 1 packet varies with the need of the manufacturer.
For example, in one preferred: -~i t, a useful product can be produced that contain~ at least about 500 grams of the ab~oLLel-l material in a bag which is about 5-3/4 inches by 10-1/4 inche~ to produce an Ah2nrh~nt packet which is quite effective in nh30~h;n~
water vapor in a shipping rnntA i n~r to preserve relative humidity without rrl.oA~;n~ liquid water back into the surrounding environment .
( e ) Exam~lcs E xample 1.
A multi-layered film comprised of a mil LU~OL~JUs film, a ga23 p~ -h~ e, gupport film and a binder to bind the microporous film to the gas p, -hl ~ film was formed. The microporous film was a microporous polypropylene sheet formed using a calcium carbonate filler according to the process described in Nago, et al.
' Structure of Microporous Polypropylene Sheets Containing CaC0 Filler", Journal of Applied Polymer Science, Vol. 45, pp. 1527-1535 ( 1992 ) .
The gas r~ -~hl~ film waG GDT-2 produced by Takuso. This multilayered film was formed into a packet containing an absorbent material c~ ~; ng a mixture of bentonite clay and calcium chloride at a ratio of 4 to 1. The packet whose dimensionG were 5-3/4 inches by 10-1/4 inches and which contained about 500 grams of the bentonite clay/calcium chloride formulation was placed within an 8 cubic foot container at a relative humidity of 80% and held at a t ~~r~A~tllre of 25~C. for about 26 days. The maximum absorption capacity of the product was tested and showed an absorption capacity of 72.5096. In addition, after the test was complete, there was no evidence of any relea3e of liquid moisture back into the ~~uL~ul-ding environment from the Ah~nrh~nt packet. The packet did not transfer liquid or saline to other material3 upon contact.
Example 2.
An additional example wa3 run on a product 3imilar to the product of Example 1 under the same conditions as in Example 1.
The absorption capacity of this product was 66.13%. No discharge of liquid water from the Ah~nrh~nt product was noted. The packet did not transfer liquid or saline to other materials upon contact.
Example 3.
An example was run on a product similar to the product of 2 t 82353 Example 1, except the ratio of the bentonite clay to the calcium chloride in the absorbent material was 3 to 2. All other conditions were the same as in Example 1. The maximum absorption capacity of this sample was 108.1596. Again, no discharge of liquid water from the Ahs-~rh~ont packet was noted. The packet did not transfer liquid or saline to other materials upon contact.
Example 4 .
An example was run on a product similar to the product of Example 1 except the ratio of the bentonite clay to calcium ~hlnr;~ in the abgorbent material was adjusted to 1:1. All other conditions were the same as in Example 1. The absorption capacity of this sample was 136.62%. No discharge of liquid water from the absorbent product was noted. The packet did not transfer liquid or saline to other materials upon contact.
Example 5. (comparison) A comparison test was peLL~ ' on a sample of the product MsD-99~, manufaatured by Australian Warehouse Solutions under the same conditions as in Example 1. The absorption capacity of this product was 47 . 97% . After the test was run, the product was damp to the touch and would transfer water or saline back to the environment .
Example 6. (comparison) A Cl , r; ~on test was performed on a sample of the product Super-0-Sec~, manufactured in France by Sodepac under the same conditions as in Example 1. The absorption capacity of this product was 53.48%. After the test was run, the product was damp 'to the touch and would transfer water or saline back to ~he environment .
Example 7. (comparison) A comparison test was performed on a sample of the product Dri-BagX, manufactured by Anders Bendt of Denmark under the same conditions as in Example 1. The absorption capacity of thi3 product was 47.49%. After the test was run, the product was damp to the touch and would transfer water or saline back to the environment .
Example 8. (c, -riq-~n) A _ ~ r; qon test wa~ performed on a sample of silica gel obtained from W.R. Grace/Davison, under the conditions as in Example l except the test was run for 14 days. The absorption capacity of the silica gel was 39.52%. After the test was run, the product was damp to the touch and would transf er water or ~3aline back to the environment.
In addition to the higher absorption capacity of the products produced according to the instant invention, the products were physically ~Y~Im; ne(l to determine if any liquid water would escape from the product. ~here was no ~l;qcPrn;hle evidence of any liquid water even after 26 dayg on r 1~q 1, 2, 3 and 4. In contrast, liquid water discharge was noted in R~ q 5, 6, 7 and 8.
( a ) Title of Invention A13SORBENT PAC~ET
( b ) Backqround of Invention --1. Field of Invention.
This invention relates to absorbent products. More sper;firAlly, this invention is an absorbent packet for use within ~hirrin~ containers for AhQnrh;n~ water vapor.
2. Prior Art.
Packets containing AhQnrhP~t and ~lp~irrAnt materials have been available for many years. The absorbent and ~lPQ-ircAnt materials are intended to absorb moisture and prevent that moisture from adversely affecting both the packets in which the absorbent or rcAnt ~tPriAlQ are rnntAinP~ and products shipped in shipping containers in which such packets are placed.
It is also well known that liquid water present in metal Qhirrinq containers can cauge rusting. The likPlihnod that these Qhirrin~ containers will rust increases if the Qhirrin~ containers are used to store products over great distances for long periods of time. For example, commercial food products are often transported in shipping containers for weeks at a time on container ships.
Often during the time the products are being shipped, the shipping containers are subjected to a variety of atmospheric conditions, inrlll~linq gituations where high hum~dity is present. Because of the si~n;firAnt amount of time n~cessAry for such long distance Qhirrin~ and the re8ulting long term exposure of the shipping containers and the products within those shipping containers to water and water vapor cau3ed by the high humidity in the atmosphere, a si~n;ficAnt rusting problem in thege Rh;rping containers now exists. This problem adversely affects not only the Rh;rrin~ containerg, but also the ~rkA~in~ for the shipped products, the products themselves and r-~hinPry utilized with the Qh i rri n~ containers .
Thus, reliable products are needed to control the relative humidity within such shipping containers for the long period of shipping. In addition, once water vapor has been Ahcnrhed into a packet, it is important that the water vapor not be released back into the Rh;rrinq container in the form of liquid water, even if the high humidity conditions continue. Such release increases the likPlih~od of rugting of the Rhirrin~ containers and the associated r-~hi nPry.
The concept of utilizing deqi ~ ~Ants or AhsorhDnt products to remove moisture from the air in ~ ju~ ion with vapor corrosion inhibitors i8 known in the art. For example, U.S. Patent Number 5,324,448 discloses a ti~Rif - Ant f~orlfAinPr which also contains vapor corrosion inhibitor. The rac~kA~in~ material for this product is a spun-bonded olefin, preferably a spun-bonded polyethylene, marketed as TYVER, a registered trademark of the DuPont de Nemours Company.
See also U.S. Patent Number 5,391,322.
Another water absorbing product is disclosed in U . S . Patent Number 5,148,613. This product is a closet drier, containing a deqi~ rAnt material for Ah5~rhin~ moisture. The pA~kA~in~ of the cover for this container is also a spun-bonded polyolefin, pref erably TYVEK~ .
~
U.S. Patent ~umber 4,856,649 discloses a deodorizer parcel wherein the structure of the parcel body is a composite material formed from a gas pl~ -hl e sheet, such as a sheet of paper or a non-woven cloth, and a plastic film, such as a polypropylene film, laminated on and bonded to the gas p ~hl e sheet. The plastic film has a multiplicity of minute pores formed by subjecting the film to irradiation with a laser beam.
U.S. Patent No. 3,745,057 discloses a 5t~rili7~h]~ package and ci~qirc~nt product wherein the film forming the cover for the package is an open-celled mi-:Lu~UlUUs film. The microporous film is formed by a process of sequential cold stretching and hot 3tretching the f ilm to impart the open-celled structure to the mi.;Lu~orous film.
Other liquid absorbing and i ~~~i7i7in~ packets are disclosed by U.S. Patent Numbers 4,748,069 and 4,749,600. The packaging for these products is a c~ ' inzltit-n of starch paper and polyvinyl acetate, which r~-k~in~ dissolves in water. See also U.S. Patent Number 4, 853, 266 .
A number of absorbent packets have also been ~li q~l oq~-d which are utilized for the shipping of hazardous liquids wherein the pArk~in~ material for those products includes an ~hsorh~nt product. ~lowever, the outside layer of the r~k~i n~ for these products is required to be i -hl e to water vapor. See, for example, U.S. Patent Number 4,969,750 and 4,927,010.
Finally, there have been a number of ~hs~rh~nt pad products which are used with food products to absorb fluids from the food.
~he FA~ Ag; ng material for these products is generally formed from a sandwich-type structure containing a liquid p ~hl e layer on one side, a liquid ; - - -hl e layer on the opposite side and a fluid absorbent inner layer between the liquid p~ --hle and - -hle layers. See, for example, U.S. Patent ~umber 4,756,939 and 4,802,574. Because the goal of these products is to absorb liquid discharge from food, liquid p,~ --h; 1 ;ty of the outside layer ia critical to these products.
While a number of these productg are useful in Ahfiorh; n~
liquids and water vapor, there is still a need for; ~v-:d absorbent products, especially Ah5r~rh-~nt packets for use in $;h;rrin~ containers to ~-;ntA;n a constant relative humidity within the container. It is critical that these Ah~)rh~nt packet3 be able to absorb large quantities of water vapor while at the same time not permit liquid water, which may form inside of the Ah~orh-~nt packet, from permeating back into the buLL~ullding environment. In addition, it is important that these absorbent packets be able to maintain relative humidity within a ~h;rr;n~ container for long periods of time regardless of changes in humidity and temperature.
In addition, it is important that these absorbent products be low cost and easy to manufacture.
Accordingly it is the object of this invention to prepare an absoLLalll packet for absorbing water vapor.
It is a further object of this invention to prepare an absorbent packet for use in ~h;rp;n~ containers which will absorb water vapor, but not permit liquid water which may form inside the packet from permeating out from the absorbent packet.
It is a still further object of this invention to prepare a low cost absorbent packet which is comprised of a multi-layered, liquid imp~ --hl~ r~k~in~ material with a mi.:Lupulous~ gas r~ -hl ~ outer layer and a gas p~ -hl ~ inner layer.
It is a still further object of this invention to produce an absorbent packet which uses as the absorbing material a combination of an alkaline earth metal salt and a clay or starch product.
It is a still further object of this invention to produce an Ah~3nrh~nt packet which not only absorbs water vapor, but maintains relative humidity within a ~hirrin~ container for long periods of time .
These and other aspects of the invention will become apparent to those skilled in the art from a cnn~ prAtion of the following d~Ailed description, drawings and claims. The description provides a selected example of construction of the device to illustrate the invention.
(c) SummarY of Invention In accordance with the present invention there i~ provided an absorbent packet for absorbing water vapor for use in a shipping container comprising (a) a gas p~ -hlR, liquid i ,- ~hle packaging material, and (b) an Ah50rhent material contained within the multi-layered packaging material.
~ r~ferab~y the ~b~orberlt n~ erial i9 = ixture of calci~m~
chloride and clay or starch. Preferably the packaging material is a multi-layer material comprised of (1) a microporous, gas pP --hle film, (2) a gas permeable, support film, and ( 3 ) a blnder to bind the microporous f ilm to the gas permeable film.
(d) Detailed DescriPtion of the Preferred Embodimer~ts Although the invention is adaptable to a wide variety of uses, it is; ' ';Pd in an absorbent packet for Ahsf)rh;n~ water vapor in a shipping container ,- ~ ~;n~ a gas ~f --hle~ liquid impermeable pA~k:~;ng material, which abgorbs water vapor but does not permit liquid water which may form within the packet from leaking out of the rA~kA~;n~ material. Preferably the rArkA~;n~ material is a multi-layered rA~-kA~in~ material comprised of a microporous, gas pp- --hlp film, a gas pf --hle support film and a binder to bind the miuLv~vLvus film to the gas p~ ~hle film. Once the rA~kA~;ng film material is formed, an absorbent material, preferably comprised of calcium ~~hl or; rl~ and a clay or starch product, is introduced between layers of the material to form a packet and then the edges of the packet are sealed to produce the absorbent packet.
When a multi-layered packaging material is used as r7P~ -r; hod above, the mi~:LV~oIUU13 film is preferably an open-celled mi.:Lvpolvus film. Microporous films are g~n~rAl ly classified in two types: closed celled films, wherein the pores of the film are not interconnected, and open-celled film, wherein the pores are essentially interconnected through tortuous paths which may extend from one exterior surface or surface region to the opposite surface region. The open-celled microporous film of this invention may be formed by a number of different processes, ;n~ Aing~ for example, cold stretching, i.e. cold drawing the elastic film until porous surface regions or areas, which are elongated normally, and hot stretching, i.e. hot drawing, wherein the film is stretched a~ter forming at a higher temperature to form the microporous product, and then heating or heat setting the porous f ilm under tension or a combination thereof. In addition, other processes can be used, for example, forming the film and then subjecting it to processes which result in microporosity, such as by subjecting it to a laser beam (as taught in U.S. Patent Number 4,856,649) or ~hf~mirAl action .
In a preferred; ~ -riir L, however, the microporous film is a mi-:Lv~Lvus polypropylene sheet containing a calcium carbonate filler. In the preferred process for forming this film, a polypropylene powder i5 mixed with the calcium carbonate filler along with certain additives, such as plasticizers and ;~ntio~ nt8. The polypropylene powder preferably ~ about 30-50% of the mixture by weight with the calcium carbonate ri~in~ preferably about 70-50%, and the additives, preferably about 1-5 % . The polypropylene powder mixture is then extruded using conventional extruding procedures at a temperature of about 200~C - 300~C to form pellets which are then subjected to a film extru~ion procedure at a temperature of about 200~C - 300~C to form n b=~e =heet. ~hi, ~he~t i/~ th~n ~tretnhed in bnth ~ lnngitudi=a1 direction and a transverse direction to f orm the micropOrouG
polypropylene sheet. The calcium carbonate filler within the polypropylene sheet assists in the formation of these micropores by partially filling the pores during the formation process. A
substantial portion of the calcium cArhonAte remains in the film after stretching, comprising as much as about 7096 of the film by weight. The fh;rknP~s of the film is from about 0.01 to 0.20 mm and preferably from 0.02 to 0.15 mm. The micropores are preferably about 1 micron in size. The preferred process for production of this film is disclosed in Nago, et al. "Structure of Ni~;Lu~oL~ u~
Polypropylene Sheets Containing CaC09 Filler", Journal of A~plied Polvmer Science, Vol. 45, pp. 1527-1535 (1992) and NA1 ~r et al.
oL.us Polypropylene Sheets Containing CaC03 Filler", Journal of Applied PolYmer Science, Vol. 49, pp. 143-150 (1993).
The gas pf -hl e film which form3 the second layer of the preferred multi-layered pA~'kA~in~ r-tPr;Al can be prepared from any conventional olP~ini~ plastic film, paper sheet or nonwoven cloth which is gas p -hle. It is critical that this film be both gas pP -hlP and water; -- --hlP and have sllffi~iPnt strength to support the mi~ ololls film layer. Preferably, this gas ~ ~hle film is yIoduc:ed from n.,l- ~ J~ polyester and/or polypropylene fibers formed into a non-woven cloth. Thi3 gas p -hle film is preferably a dry-type, wet-type or spun-bond, non-woven cloth, with the more preferred material being manufactured by Takuso under the name GDT-2 or TYVEK~ manufactured by DuPont. This film preferably weighs between about 10 and 400 g/m2, preferably between 20 and 200 g/m2, has a porosity in Gurley seconds from about 2 to about 50 3econds and a thi~-knP1;s from about 0.05 to about 0.2 mm.
In order to provide additional strength for the packaging material, these two films are bound together, preferably by an adhesive. Any conventional adhe3ive is acceptable which doe3 not interfere with the ga3 p -hility of the compo3ite film. Thu3, it is critical that the adhesive layer between the3e two layer3 not be applied too thickly or cover too much of the 3urface of either of the two films 30 a3 to prevent the pa33age of water vapor through both layer3. Accordingly, preferably the adhe3ive material i3 placed between the layer3 in a (1; ~ nnPcted or discontinuou3 pattern wherein the area3 of adhe3ive material are 3eparated by non-coated area3, for example, in a grid-like 3tructure or a regular dot 3tructure a3 di3clo3ed, for example, in U.S. Patent No.
4,725,465. For example, a me3h-like 3tructure may be utilized, wherein the open 3pace between the me3h i3 at lea3t from about .05 micron3 to about 3 micron3. Alternatively, individual dot3 of adhe3ive can be placed between the layers, wherein the dots are about 1 micron in diameter and 3eparated f rom each other by about to 5 micron3 . Pref erably at lea3t about 4 0 percent of each f ilm remain3 ull~vve~ed by the adhe3ive. In a preferred ' -'i 1 the adhe3ive material is a polyurethane prepolymer solution manufactured under the name Unoflex J-3, by Sanyo ChPrnic~
Industries, Ltd.
The overall thi~knP~s of the preferred multi-layered packaging material is about 0.1 to about l.0 mm., preferably about 0.1 to '~ 2 1 82353 about 0 . 3 mm.
The absorbent material which is introduced into the absorbent packet can be any absorbing material with an PnhAnrPd capacity to absorb water vapor and which is also relatively low in cost.
Preferably, the material should be able to absorb an amount of water up to at least about 509~ of the dry weight of the absorbent material. The preferred absorbing material should exhibit high ab60rbing capacity f or water vapor in ambient air conditions over long periods of time. The types of absorption materials that can be used include those commonly utilized in water absorbing products, such as an alkali-metal polyacrylate or an AlkAlinp-metal partial salt of a cross linked poly (propenoic acid), such as a sodium or potas3ium polyacrylate or a partial sodium salt of poly (propenoic acid). Alternatively, and preferably, the absorption material is a c~ ' ;nAt;on of an inorganic AlkAl;nP earth salt, such as calcium chloride mixed with a clay or starch product. The calcium chloride is mixed with the clay or starch at a ratio f rom about 1 to 9 to about 3 to 7 and preferably from about 1 to 4 to about 1 to 1.
The clay mineral that may be used as an element of the absorbent product is preferably a smectite-type clay, especially an AlkAl ;nP earth 8mectite guch as calcium smectite, with a water uptake capacity ( in termg of the dried smectite with a residual water content of about 6 weight percent) of at least about 5096, preferably about 60 to 130~, more preferably about 90 to 12096.
Alternatively, the smectite may be a sodium Al k~l i nP smectite 2 1 ~2353 containing prf~l inqntly sodium ions as the rerlA~Ahle cations and exhibiting a water uptake capacity of at least about 5096 (with a residual water content of about 6 weight percent). Alternatively, a v~rmic~ll ite or filler material such as wood fiber, paper pulp or other water absorbing materials can be used to replace a portion of the clay material.
If instead a starch product is used, pre~erably it is a potato starch with an absorption capacity of about 10-12 mls of water per gram of starch material. Preferable material is a potato starch produced by Avebe in Veendam, Holland.
In the process for the preparation of this Ahs~rhAnt packet, the multi-layered, gas pP -~hl~ rA~kA~in~ material is first formed. In the formation of this gas ~- ~hl~, liquid i ~hle multi-layered pA~knging ~-t~ri~l ~ the miuLu~uLuua film, preferably a microporous polypropylene sheet material containing calcium carbonate, is prepared using the process as disclosed in ~ago, et al. "Structure of ~licroporous Polypropylene Sheets Containing CaC03 Filler", Journal of Al~plied Polymer Science, Vol. 45, pp. 1527-1535 (1992). Once this mi~:Lo~,Lvus polypropylene sheet is prepared, the gas p~ h~ e film of the type previously di3cussed is then prepared. The miuLu~uL~us film is then bound to the gas p~ -hle film by use of the adhesive material previously discussed. The adhesive should be applied 80 as to leave a si~nifi.-Ant portion of the surface of the composite film uncovered, thus allowing water vapor to pass through both layers. Preferably the gas p~ -qhle~
mi~:Lu~ùL~ s film is formed as the inner layer of the composite .
packaging material and the support ~ilm forms the outer layer of the composite material.
Once the multi-layered r~ork~ing material is formed, a continuous Ahsnrh~nt packet forming procedure is preferably used wherein the AhE~orh~ont material i6 placed between two sheets of the gas p~ -ohle~ multi-layered rn~kA~in~ material and the edges of the sheets are sealed, preferably by heat sealing. Alternatively, a single sheet of the composite, gas r~ -hl.~, liquid i -- ~hle sheet is produced and is folded over on itself after incorporation of the Ahsnrh~nt material into the packet. The 1~ i n; ng edges of the sheet are sealed, preferably heat sealed, to ~-nrnr~-llAte the absorbent material. The amount of the absorbent material llt;l;~ed in the nhsn 1 _ 1 packet varies with the need of the manufacturer.
For example, in one preferred: -~i t, a useful product can be produced that contain~ at least about 500 grams of the ab~oLLel-l material in a bag which is about 5-3/4 inches by 10-1/4 inche~ to produce an Ah2nrh~nt packet which is quite effective in nh30~h;n~
water vapor in a shipping rnntA i n~r to preserve relative humidity without rrl.oA~;n~ liquid water back into the surrounding environment .
( e ) Exam~lcs E xample 1.
A multi-layered film comprised of a mil LU~OL~JUs film, a ga23 p~ -h~ e, gupport film and a binder to bind the microporous film to the gas p, -hl ~ film was formed. The microporous film was a microporous polypropylene sheet formed using a calcium carbonate filler according to the process described in Nago, et al.
' Structure of Microporous Polypropylene Sheets Containing CaC0 Filler", Journal of Applied Polymer Science, Vol. 45, pp. 1527-1535 ( 1992 ) .
The gas r~ -~hl~ film waG GDT-2 produced by Takuso. This multilayered film was formed into a packet containing an absorbent material c~ ~; ng a mixture of bentonite clay and calcium chloride at a ratio of 4 to 1. The packet whose dimensionG were 5-3/4 inches by 10-1/4 inches and which contained about 500 grams of the bentonite clay/calcium chloride formulation was placed within an 8 cubic foot container at a relative humidity of 80% and held at a t ~~r~A~tllre of 25~C. for about 26 days. The maximum absorption capacity of the product was tested and showed an absorption capacity of 72.5096. In addition, after the test was complete, there was no evidence of any relea3e of liquid moisture back into the ~~uL~ul-ding environment from the Ah~nrh~nt packet. The packet did not transfer liquid or saline to other material3 upon contact.
Example 2.
An additional example wa3 run on a product 3imilar to the product of Example 1 under the same conditions as in Example 1.
The absorption capacity of this product was 66.13%. No discharge of liquid water from the Ah~nrh~nt product was noted. The packet did not transfer liquid or saline to other materials upon contact.
Example 3.
An example was run on a product similar to the product of 2 t 82353 Example 1, except the ratio of the bentonite clay to the calcium chloride in the absorbent material was 3 to 2. All other conditions were the same as in Example 1. The maximum absorption capacity of this sample was 108.1596. Again, no discharge of liquid water from the Ahs-~rh~ont packet was noted. The packet did not transfer liquid or saline to other materials upon contact.
Example 4 .
An example was run on a product similar to the product of Example 1 except the ratio of the bentonite clay to calcium ~hlnr;~ in the abgorbent material was adjusted to 1:1. All other conditions were the same as in Example 1. The absorption capacity of this sample was 136.62%. No discharge of liquid water from the absorbent product was noted. The packet did not transfer liquid or saline to other materials upon contact.
Example 5. (comparison) A comparison test was peLL~ ' on a sample of the product MsD-99~, manufaatured by Australian Warehouse Solutions under the same conditions as in Example 1. The absorption capacity of this product was 47 . 97% . After the test was run, the product was damp to the touch and would transfer water or saline back to the environment .
Example 6. (comparison) A Cl , r; ~on test was performed on a sample of the product Super-0-Sec~, manufactured in France by Sodepac under the same conditions as in Example 1. The absorption capacity of this product was 53.48%. After the test was run, the product was damp 'to the touch and would transfer water or saline back to ~he environment .
Example 7. (comparison) A comparison test was performed on a sample of the product Dri-BagX, manufactured by Anders Bendt of Denmark under the same conditions as in Example 1. The absorption capacity of thi3 product was 47.49%. After the test was run, the product was damp to the touch and would transfer water or saline back to the environment .
Example 8. (c, -riq-~n) A _ ~ r; qon test wa~ performed on a sample of silica gel obtained from W.R. Grace/Davison, under the conditions as in Example l except the test was run for 14 days. The absorption capacity of the silica gel was 39.52%. After the test was run, the product was damp to the touch and would transf er water or ~3aline back to the environment.
In addition to the higher absorption capacity of the products produced according to the instant invention, the products were physically ~Y~Im; ne(l to determine if any liquid water would escape from the product. ~here was no ~l;qcPrn;hle evidence of any liquid water even after 26 dayg on r 1~q 1, 2, 3 and 4. In contrast, liquid water discharge was noted in R~ q 5, 6, 7 and 8.
Claims (20)
1. An absorbent packet for absorbing water vapor in a container comprising (a) a gas permeable, water impermeable packaging material, and (b) an absorbent material contained within the gas permeable liquid impermeable packaging material.
2. An absorbent packet for absorbing water vapor in a container comprising (a) a gas permeable, water impermeable packaging material comprising a microporous, gas permeable film, a gas permeable support film and a binder that binds the microporous film to the gas permeable support film; and (b) an absorbent material contained within the gas permeable, water permeable packaging material.
3. The absorbent packet of Claim 2 wherein the microporous film is a non-woven polyethylene or polypropylene film.
4. The absorbent packet of Claim 2 wherein the microporous film is an open celled microporous film.
5. The absorbent packet of Claim 2 wherein the microporous film is a microporous polypropylene film containing calcium carbonate.
6. The absorbent packet of Claim 5 wherein the microporous film contains at least about 30% calcium carbonate.
7. The absorbent packet of Claim 2 wherein the microporous film is formed from approximately 30 to 50% polypropylene powder, approximately 70 to 50% calcium carbonate and approximately 1 to 5%
additives.
additives.
8. The absorbent packet of Claim 1 wherein the absorbent material is a combination of calcium chloride and clay.
9. The absorbent packet of Claim 2 wherein the absorbent material is a combination of calcium chloride and clay.
10. The absorbent packet of Claim 8 wherein the percentage of the calcium chloride is from about 20 to about 80%.
11. The absorbent packet of Claim 9 wherein the percentage of the calcium chloride is from about 20 to about 80%.
12. The absorbent packet of Claim 1 wherein the absorbent material is a combination of calcium chloride and starch.
13. The absorbent packet of Claim 2 wherein the absorbent material is a combination of calcium chloride and starch.
14. The absorbent packet of Claim 8 wherein the clay is a smectite-type clay with a water uptake capacity of at least about 50%.
15. The absorbent packet of Claim 9 wherein the clay is a smectite-type clay with a water uptake capacity of at least about 50%.
16. The absorbent packet of Claim 1 wherein the binder is secured to the microporous film and the gas permeable film in a regular pattern.
17. The absorbent packet of Claim 1 where the gas permeable, water impermeable packaging material includes a microporous film comprised of a non-woven polyethylene or polypropylene film.
18. The absorbent package of Claim 11 wherein the microporous film is formed from approximately 30 to about 50% polypropylene powder, approximately 70 to 50% calcium carbonate, approximately 1 to 5% additives.
19. The absorbent packet of Claim 17 wherein the absorbent material contained within the gas permeable liquid impermeable packaging material is a combination of calcium chloride and clay.
20. The absorbent packet of Claim 19 wherein the ratio of the calcium chloride to clay is at least about 1:4.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/612,276 | 1996-03-07 | ||
| US08/612,276 US5773105A (en) | 1996-03-07 | 1996-03-07 | Absorbent packet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2182353A1 true CA2182353A1 (en) | 1997-09-08 |
Family
ID=24452486
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2182353 Abandoned CA2182353A1 (en) | 1996-03-07 | 1996-07-30 | Absorbent packet |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5773105A (en) |
| EP (1) | EP0793992A3 (en) |
| JP (1) | JPH09295680A (en) |
| CN (1) | CN1159362A (en) |
| CA (1) | CA2182353A1 (en) |
| SG (1) | SG49981A1 (en) |
Families Citing this family (58)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE29503009U1 (en) * | 1995-02-23 | 1995-06-14 | Schloesser Ulrich | Plant substrate |
| USRE40941E1 (en) * | 1995-04-19 | 2009-10-20 | Csp Technologies, Inc. | Monolithic polymer composition having a releasing material |
| US6124006A (en) * | 1995-04-19 | 2000-09-26 | Capitol Specialty Plastics, Inc. | Modified polymers having controlled transmission rates |
| US6221446B1 (en) | 1995-04-19 | 2001-04-24 | Capitol Specialty Plastics, Inc | Modified polymers having controlled transmission rates |
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-
1996
- 1996-03-07 US US08/612,276 patent/US5773105A/en not_active Expired - Lifetime
- 1996-06-10 EP EP19960109266 patent/EP0793992A3/en not_active Ceased
- 1996-07-30 CA CA 2182353 patent/CA2182353A1/en not_active Abandoned
- 1996-08-26 JP JP22391896A patent/JPH09295680A/en not_active Withdrawn
- 1996-10-08 SG SG1996010823A patent/SG49981A1/en unknown
- 1996-10-22 CN CN96122003A patent/CN1159362A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09295680A (en) | 1997-11-18 |
| EP0793992A3 (en) | 1997-11-26 |
| CN1159362A (en) | 1997-09-17 |
| SG49981A1 (en) | 1998-06-15 |
| US5773105A (en) | 1998-06-30 |
| EP0793992A2 (en) | 1997-09-10 |
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