USRE35285E - Thermoplastic multi-layer packaging film and bags made therefrom - Google Patents
Thermoplastic multi-layer packaging film and bags made therefrom Download PDFInfo
- Publication number
- USRE35285E USRE35285E US08/085,468 US8546893A USRE35285E US RE35285 E USRE35285 E US RE35285E US 8546893 A US8546893 A US 8546893A US RE35285 E USRE35285 E US RE35285E
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- Prior art keywords
- layer
- ethylene
- copolymer
- heat
- copolymers
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
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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.]
- Y10T428/1328—Shrinkable or shrunk [e.g., due to heat, solvent, volatile agent, restraint removal, etc.]
-
- 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.]
- Y10T428/1334—Nonself-supporting tubular film or bag [e.g., pouch, envelope, packet, etc.]
- Y10T428/1341—Contains vapor or gas barrier, polymer derived from vinyl chloride or vinylidene chloride, or polymer containing a vinyl alcohol unit
-
- 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
- Y10T428/28—Web or sheet containing structurally defined element or component and having an adhesive outermost layer
- Y10T428/2813—Heat or solvent activated or sealable
- Y10T428/2817—Heat sealable
- Y10T428/2826—Synthetic resin or polymer
-
- 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
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31725—Of polyamide
- Y10T428/3175—Next to addition polymer from unsaturated monomer[s]
-
- 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
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31725—Of polyamide
- Y10T428/3175—Next to addition polymer from unsaturated monomer[s]
- Y10T428/31757—Polymer of monoethylenically unsaturated hydrocarbon
-
- 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
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31855—Of addition polymer from unsaturated monomers
- Y10T428/31909—Next to second addition polymer from unsaturated monomers
- Y10T428/31913—Monoolefin polymer
-
- 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
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31855—Of addition polymer from unsaturated monomers
- Y10T428/31909—Next to second addition polymer from unsaturated monomers
- Y10T428/31913—Monoolefin polymer
- Y10T428/3192—Next to vinyl or vinylidene chloride polymer
-
- 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
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31855—Of addition polymer from unsaturated monomers
- Y10T428/31909—Next to second addition polymer from unsaturated monomers
- Y10T428/31928—Ester, halide or nitrile of addition polymer
Definitions
- the invention relates to thermoplastic multi-layer packaging films and bags or pouches made therefrom.
- this invention relates to films and bags having superior heat shrink and cold seal properties, which give good seal strength even through contamination like grease or blood, and which allow the application of higher shrink temperatures due to their improved seal strength at elevated temperatures.
- Shrinkable and heat sealable thermoplastic films are being used in packaging of non-food and food products like meat, cheese, poultry and the like. Many attempts have been made to combine good shrink properties with satisfactory sealability and good seal strength both at room temperature and at higher temperatures but there is still room for improvement.
- a laminate film known from U.S. Pat. No. 3,741,253 comprises a core layer of a vinylidene chloride copolymer between a layer of a cross-linked ethylene-vinyl acetate copolymer used as a sealant and an outer layer of ethylene-vinylacetate copolymer which is not cross-linked.
- the ethylene-vinylacetate copolymer has improved properties over the previously used polyethylene, especially when it has been cross-linked by irradiation.
- the core layer may also consist of a hydrolized ethylene-vinyl acetate copolymer. It has similar oxygen barrier properties as vinylidene chloride copolymers and often the advantage that it may be irradiated without discoloration.
- linear low density polyethylenes More recently low density linear polyethylenes have become commercially available and have also been proposed for packaging applications. Actually the so called linear low density polyethylenes are copolymers of ethylene and varying amounts of higher ⁇ -olefins with e.g. 5 to 10 carbon atoms per molecule (U.S. Pat. No. 4,076,698) or 3 to 8 carbon atoms per molecule (published European patent application No. 120503). Depending on their density these materials are referred to as linear low density polyethylene (LLDPE) or very low density polyethylene (VLDPE), the separation line being at a density of about 0.910 g/cm 3 .
- LLDPE linear low density polyethylene
- VLDPE very low density polyethylene
- VLDPE Plastics Technology, September 1984, page 113 and October 1984, page 13 as well as in a company brochure published in February 1984 by DSM in the Netherlands and entitled "Stamilex PE". Their properties are said to be a unique combination between those of standard polyethylene and polyolefmic rubbers. Their sealability and their compatibility with other polymers has been mentioned.
- the heat sealing layer comprises a copolymer of ethylene and 12 to 20% by weight, based on the copolymer, of an ⁇ -olefin with 4 to 8 carbon atoms.
- both the heat shrink properties and the cold seal strength of the laminated packaging film depend on the comonomer content of the ethylene copolymer used as the sealing layer.
- the comonomer content must increase when going from the C 4 - ⁇ -olefin (butene(1) to the C 8 - ⁇ -olefin (octene(1).
- the films of the present invention exhibit improved shrink properties both in irradiated (cross-linked) and non-irradiated condition and that these properties as well as the seal strength are a function of the comonomer content of the linear low and very low density "polyethylene".
- the comonomer content should be between 10 and 20% by weight, based on the copolymer. Such copolymers have a density of less than 915 kg/m 3 .
- the comonomer content should preferably be increased to between 12 and 25% by weight, based on the copolymer. Such copolymers have a density of less than 920 kg/m 3 .
- ethylene/ ⁇ -olefin copolymer with up to 50% by weight, based on the sealing layer composition, of a polymer which is compatible with said ethylene/ ⁇ -olefin copolymer.
- a polymer which is compatible with said ethylene/ ⁇ -olefin copolymer may preferably be selected from the group comprising linear low density polyethylene (LLDPE) with a density above 920 kg/m 3 , linear high density polyethylene (LHDPE), low density polyethylene (LDPE), ethylene vinyl acetate (EVA), acid modified EVA, polypropylene, ethylene/propylene copolymer, ionomeric polymers and ethylene/alkylacrylate copolymers wherein the alkyl moiety has 1 to 8 C atoms, in particular ethylenemethylacrylate (EMA), ethylene-ethylacrylate (EEA) and ethylene-butylacrylate (EBA).
- LLDPE linear high density polyethylene
- LDPE low density polyethylene
- EVA
- the ethylene/alkylacrylate copolymer which can be blended with the ethylene/ ⁇ -olefin in the heat sealing layer can comprise 3 to 30% by weight of alkylacrylate.
- the ethylene copolymer forming the sealing layer may be cross-linked by irradiation in order to improve its shrink characteristics and mechanical properties.
- cross-linking is not necessary since a very satisfactory packaging film is also obtained without irradiation.
- polyvinylidene chloride is used as core layer providing an oxygen barrier the irradiation should take place prior to the lamination of the core layer to the sealing layer since PVDC may suffer when exposed to high energy irradiation.
- the entire multi-layer film may be irradiated if the PVDC core layer is substituted by a core layer of partly hydrolyzed ethylene vinyl-acetate copolymer (EVOH). PVDC and EVOH are the preferred core layers since they show outstanding oxygen barrier properties.
- the films are normally oriented in longitudinal and transversal direction to obtain the desired shrink properties. If a tubular film is produced by extrusion the orientation may be effected using the known air bubble method and further stretching the film by pulling. Alternatively, orientation may be achieved by deep drawing of a planar film.
- the outer layer of the multi-layer packaging film of the invention may be of the same ethylene copolymer as the sealing layer, i.e. an ethylene/ ⁇ -olefin copolymer comprising 10 to 25% by weight, based on the copolymer, of an ⁇ -olefin with 4 to 8 carbon atoms, said copolymer having a density of less than 920 kg/m 3 ethylene vinyl acetate and polyamides, and ionomeric resins. It may frequently be of advantage if an adhesive layer and/or an adhesion promoting layer is interposed between said other layers.
- a bag may be formed from a tubular film in that the bottom of the bag is formed by a transverse seal across the flattened tube and the mouth is formed by severing the tube at a pre-selected distance from said transverse seal.
- Pouches can be obtained by sealing two film sheets at three edges.
- the approach with this test is to immerse total seal areas into hot water and after a predetermined dwell time, the pressure inside the bag is increased at a constant rate of approx. 25.4 mm of water per second until the seal fails.
- the mm of water pressure, at the level at which the seal fails, are recorded, and there are minimum specifications expressed in mm for each bag width. The highest is the number, the better is the seal quality at that temperature.
- the percent shrink is measured immersing for a couple of seconds in hot water a specimen and measuring the percent of retraction, both in the longitudinal and transversal direction. The highest is the percent of shrink, the better is the performance of the material in terms of package presentation.
- the maximum achievable percent of shrink is that measured at the temperature at which the material meets the minimum VPHB requirements expressed in mm of water pressure (see point A). To predict the shrink behaviour it is therefore useful to plot in the same diagram the % of shrink and the VPHB as a function of the temperature.
- the cold seal strength represents the seal quality at room temperature and predicts the seal performance when the bag is loaded with a product either manually or by means of automatic loaders, which operate with a pusher, which pushes the product into the bag.
- the cold seal strength is measured with a modified pusher of a commercial loader, equipped with a system to record the pressure necessary to open the bottom seal.
- the head of the pusher operates on a 6 cm length of seal and the cold seal strength is expressed in kg/6 cm.
- the maximum pressure recordable with this systems is 40 kg/6 cm.
- Multi-layer packaging films of the composition summarized below in table I were prepared in the following manner.
- the first two layers A and B were coextruded through a conventional tubular extruder to form a tube.
- the substrate was cooled and flattened. It was then sent through an irradiation vault where it was irradiated by high energy electrons to a dosage of about 4.5 MR. Depending on the characteristics desired this dosage could vary from 2 to 20 MR.
- the substrate was again inflated and sent through a first tubular extrusion coating die where it received a coating of vinylidene chloride copolymer.
- the film passed through a second tubular extrusion coating die where it received a layer of ethylene-vinyl acetate copolymer.
- the film was cooled, collapsed and rolled-up.
- This tape was subsequently unrolled, fed through a bath of hot water, held at a temperature of about 80° to 98° C., and as it left the water it was inflated and blown into thin tubing with a total wall thickness of about 59 microns.
- This so-called "trapped bubble” technique is well known in the art.
- the film was then rapidly cooled to set the orientation and then rolled up for further processing.
- the polyvinylidene chloride and the ethylene-vinylacetate copolymer can alternatively be coated onto the substrate using a two-ply coextrusion die.
- Examples 1, 2 and 3 show that excellent shrink characteristics and a very good seal strength both at room temperature and at elevated temperatures are being obtained. It has further been found that the seal strength is not significantly affected by contamination like grease or blood. Comparisons 3 and 4 show that a very significant decrease both in seal strength and percent shrink occur when the comonomer content in the ethylene ⁇ -olefin copolymer drops below a certain level, i.e. the minimum comonomer content is an essential feature if the combination of desired properties is to be achieved.
- Multi-layer packaging films of the composition summarized in the following table III were produced by conventional techniques, i.e. by coextruding a tubular film of layers A to F and subsequent stretching and orientation, e.g. in the blown-up bubble, so as to obtain a heat shrinkable film. No irradiation was employed in this case.
- the test results obtained are tabulated in the following table IV.
Abstract
A thermoplastic, multi-layer packaging film is disclosed which comprises at least 5 layers in which one surface layer is a heat sealing layer and one of the internal layers is a barrier layer. The heat sealing surface layer comprises a copolymer of ethylene and an alpha-olefin having 4 to 8 carbon atoms per molecule and said copolymer comprises 90% to 75% ethylene and 10% to 25% alpha-olefin having 4 to 8 carbon molecules and a density of less than 915 kg/m2. The heat sealing layer may also comprise a blend of the aformentioned copolymer with an ethylene/vinyl-acetate copolymer or an ethylene/butyl-acrylate copolymer. The film can be oriented to be heat shrinkable and can be formed into bags by heat sealing portions of the sealing surfaces together. The heat seals have superior cold strength and minimize seal failure when the bags are loaded with relatively heavy products.
Description
.Iadd.This application is a continuation of application Ser. No. 648,480 filed on Jan. 30, 1991, now abandoned, which in turn is a reissue of U.S. Pat. No. 4,801,486. .Iaddend.
The invention relates to thermoplastic multi-layer packaging films and bags or pouches made therefrom. In particular this invention relates to films and bags having superior heat shrink and cold seal properties, which give good seal strength even through contamination like grease or blood, and which allow the application of higher shrink temperatures due to their improved seal strength at elevated temperatures.
Shrinkable and heat sealable thermoplastic films are being used in packaging of non-food and food products like meat, cheese, poultry and the like. Many attempts have been made to combine good shrink properties with satisfactory sealability and good seal strength both at room temperature and at higher temperatures but there is still room for improvement.
A laminate film known from U.S. Pat. No. 3,741,253 comprises a core layer of a vinylidene chloride copolymer between a layer of a cross-linked ethylene-vinyl acetate copolymer used as a sealant and an outer layer of ethylene-vinylacetate copolymer which is not cross-linked. The ethylene-vinylacetate copolymer has improved properties over the previously used polyethylene, especially when it has been cross-linked by irradiation.
As disclosed in U.S. Pat. No. 4,064,296 the core layer may also consist of a hydrolized ethylene-vinyl acetate copolymer. It has similar oxygen barrier properties as vinylidene chloride copolymers and often the advantage that it may be irradiated without discoloration.
Certain advantages have been achieved by using an ionomeric resin as sealing layer. They result in a higher seal strength at elevated temperatures thus allowing higher shrink temperatures. However, their cold seal strength is not fully satisfactory. This latter property is important in modern automated bag packaging processes in which the seals are subjected to substantial stress when the bags are opened and loaded with the article to be packed.
More recently low density linear polyethylenes have become commercially available and have also been proposed for packaging applications. Actually the so called linear low density polyethylenes are copolymers of ethylene and varying amounts of higher α-olefins with e.g. 5 to 10 carbon atoms per molecule (U.S. Pat. No. 4,076,698) or 3 to 8 carbon atoms per molecule (published European patent application No. 120503). Depending on their density these materials are referred to as linear low density polyethylene (LLDPE) or very low density polyethylene (VLDPE), the separation line being at a density of about 0.910 g/cm3. Some properties of VLDPE have been described in Plastics Technology, September 1984, page 113 and October 1984, page 13 as well as in a company brochure published in February 1984 by DSM in the Netherlands and entitled "Stamilex PE". Their properties are said to be a unique combination between those of standard polyethylene and polyolefmic rubbers. Their sealability and their compatibility with other polymers has been mentioned.
It is an object of the present invention to provide a multi-layer laminated packaging film and bags made therefrom which have improved shrink characteristics over the materials used in the past. This means that at a given temperature the shrink in percent (the mean between the shrink in the longitudinal and transversal direction) should be higher and the tolerated maximum shrink temperature should also be higher. The maximum shrink temperature is dependent on the seal strength at elevated temperatures.
It is a further object of this invention to provide a packaging material with improved cold seal strength and thereby a reduced risk of breakages when bags made of the film material are utilized in automated loading processes.
It is yet another object of the present invention to provide a packaging material which gives reliable seals even when contaminated. Especially in the packaging of meat it frequently occurs that the sealing areas are contaminated with grease or blood, both of which tend to impair the sealing between hitherto used sealing layers.
Finally and most importantly it is an object of this invention to provide a material combining the above advantages, i.e. improved shrinkability, increased maximum shrink temperature, good cold seal strength and sealability through contamination.
It has been found that the above-mentioned objects are achieved by the present invention which is directed to a thermoplastic multi-layer packaging film comprising at least an outer polymer layer, an inner heat sealing layer and optionally an oxygen barrier layer between said inner and said outer layer, and which is characterized in that the heat sealing layer comprises a copolymer of ethylene and x to y% by weight, based on the copolymer, of an α-olefin with 4 to 8 carbon atoms, whereby x=0.5nC +8 and y=1.25nC +15 will nC being the number of carbon atoms in the α-olefin, said copolymer having a density of less than 920 kg/m3.
Preferably the heat sealing layer comprises a copolymer of ethylene and 12 to 20% by weight, based on the copolymer, of an α-olefin with 4 to 8 carbon atoms.
It has surprisingly been found that both the heat shrink properties and the cold seal strength of the laminated packaging film depend on the comonomer content of the ethylene copolymer used as the sealing layer. In order to achieve optimal results the comonomer content must increase when going from the C4 -α-olefin (butene(1) to the C8 -α-olefin (octene(1). It is particularly surprising that the films of the present invention exhibit improved shrink properties both in irradiated (cross-linked) and non-irradiated condition and that these properties as well as the seal strength are a function of the comonomer content of the linear low and very low density "polyethylene".
When using a copolymer of ethylene and butene (1) the comonomer content should be between 10 and 20% by weight, based on the copolymer. Such copolymers have a density of less than 915 kg/m3. When employing a copolymer of ethylene and octene (1) the comonomer content should preferably be increased to between 12 and 25% by weight, based on the copolymer. Such copolymers have a density of less than 920 kg/m3.
According to the invention it is also possible to blend the ethylene/α-olefin copolymer with up to 50% by weight, based on the sealing layer composition, of a polymer which is compatible with said ethylene/α-olefin copolymer. Such further polymer may preferably be selected from the group comprising linear low density polyethylene (LLDPE) with a density above 920 kg/m3, linear high density polyethylene (LHDPE), low density polyethylene (LDPE), ethylene vinyl acetate (EVA), acid modified EVA, polypropylene, ethylene/propylene copolymer, ionomeric polymers and ethylene/alkylacrylate copolymers wherein the alkyl moiety has 1 to 8 C atoms, in particular ethylenemethylacrylate (EMA), ethylene-ethylacrylate (EEA) and ethylene-butylacrylate (EBA).
The ethylene/alkylacrylate copolymer which can be blended with the ethylene/α-olefin in the heat sealing layer can comprise 3 to 30% by weight of alkylacrylate.
According to one embodiment of the invention the ethylene copolymer forming the sealing layer may be cross-linked by irradiation in order to improve its shrink characteristics and mechanical properties. However, such cross-linking is not necessary since a very satisfactory packaging film is also obtained without irradiation. If polyvinylidene chloride is used as core layer providing an oxygen barrier the irradiation should take place prior to the lamination of the core layer to the sealing layer since PVDC may suffer when exposed to high energy irradiation. The entire multi-layer film may be irradiated if the PVDC core layer is substituted by a core layer of partly hydrolyzed ethylene vinyl-acetate copolymer (EVOH). PVDC and EVOH are the preferred core layers since they show outstanding oxygen barrier properties.
The films are normally oriented in longitudinal and transversal direction to obtain the desired shrink properties. If a tubular film is produced by extrusion the orientation may be effected using the known air bubble method and further stretching the film by pulling. Alternatively, orientation may be achieved by deep drawing of a planar film.
The outer layer of the multi-layer packaging film of the invention may be of the same ethylene copolymer as the sealing layer, i.e. an ethylene/α-olefin copolymer comprising 10 to 25% by weight, based on the copolymer, of an α-olefin with 4 to 8 carbon atoms, said copolymer having a density of less than 920 kg/m3 ethylene vinyl acetate and polyamides, and ionomeric resins. It may frequently be of advantage if an adhesive layer and/or an adhesion promoting layer is interposed between said other layers.
If bags are made from the film material the film will normally be folded so that the fold forms the bottom of the bag whereafter both sides are sealed so that the side seals close both sides of the bag. Alternatively a bag may be formed from a tubular film in that the bottom of the bag is formed by a transverse seal across the flattened tube and the mouth is formed by severing the tube at a pre-selected distance from said transverse seal. Pouches can be obtained by sealing two film sheets at three edges.
The invention will be further illustrated by reference to the following examples without being limited thereto.
The following test methods were used to investigate the properties of the packaging films and to compare them with other materials,
This is a test to determine the seal quality of shrinkable materials at different temperatures. The approach with this test is to immerse total seal areas into hot water and after a predetermined dwell time, the pressure inside the bag is increased at a constant rate of approx. 25.4 mm of water per second until the seal fails.
The mm of water pressure, at the level at which the seal fails, are recorded, and there are minimum specifications expressed in mm for each bag width. The highest is the number, the better is the seal quality at that temperature.
The percent shrink is measured immersing for a couple of seconds in hot water a specimen and measuring the percent of retraction, both in the longitudinal and transversal direction. The highest is the percent of shrink, the better is the performance of the material in terms of package presentation.
In practice, the maximum achievable percent of shrink is that measured at the temperature at which the material meets the minimum VPHB requirements expressed in mm of water pressure (see point A). To predict the shrink behaviour it is therefore useful to plot in the same diagram the % of shrink and the VPHB as a function of the temperature.
The cold seal strength represents the seal quality at room temperature and predicts the seal performance when the bag is loaded with a product either manually or by means of automatic loaders, which operate with a pusher, which pushes the product into the bag. The cold seal strength is measured with a modified pusher of a commercial loader, equipped with a system to record the pressure necessary to open the bottom seal. The head of the pusher operates on a 6 cm length of seal and the cold seal strength is expressed in kg/6 cm. The maximum pressure recordable with this systems is 40 kg/6 cm.
The reported results are the average of 10 measurements.
The following raw materials were used in the examples:
__________________________________________________________________________
RAW MATERIALS
ABBREVIATION
COMPOSITION MELTING POINT
DENSITY (g/cm.sup.3)
__________________________________________________________________________
E/15% B ethylene-butene copolym., 15% butene
118° C.
0.906
E/8% B ethylene-butene copolym., 8% butene
121.5° C.
0.918
E/6% VA ethylene-vinylacetate copolym., 6% VA
105° C.
0.926
E/9% VA ethylene-vinylacetate cop., 9% VA
96° C.
0.929
E/14% VA ethylene-vinylacetate copolym., 14% VA
90° C.
0.932
E/18% VA ethylene-vinylacetate cop., 18% VA
91° C.
0.940
Ionomer (Na)
Ionomeric resin (Na salt)
90-92° C.
0.940
E/19% O ethylene-octene copolym., 19% octene
124° C.
0.911
E/13% O ethylene-octene copolym., 13% octene
124° C.
0.915
E/10.5% O ethylene-octene copolym., 10.5% octene
123° C.
0.920
Acid modif. EVA
acid modified Ethylene-Vinylacetate
(55° C.)
0.948
PA Polyamide (Nylon 6,12 copolymer)
140-147° C.
1.06
EMA (20% MA)
ethylene-methylacrylate copolym., 20% MA
85-90° C.
0.942
EBA (7% BA)
ethylene-butylacrylate copolym. 7% BA
98-108° C.
0.923
P/4.5% E propylene-ethylene copolym., 4.5% E
135° C.
0.900
__________________________________________________________________________
Multi-layer packaging films of the composition summarized below in table I were prepared in the following manner. The first two layers A and B were coextruded through a conventional tubular extruder to form a tube. After leaving the die the substrate was cooled and flattened. It was then sent through an irradiation vault where it was irradiated by high energy electrons to a dosage of about 4.5 MR. Depending on the characteristics desired this dosage could vary from 2 to 20 MR. After leaving the irradiation vault the substrate was again inflated and sent through a first tubular extrusion coating die where it received a coating of vinylidene chloride copolymer. Thereafter the still inflated and now triple-walled film passed through a second tubular extrusion coating die where it received a layer of ethylene-vinyl acetate copolymer. After the final coating the film was cooled, collapsed and rolled-up. This tape was subsequently unrolled, fed through a bath of hot water, held at a temperature of about 80° to 98° C., and as it left the water it was inflated and blown into thin tubing with a total wall thickness of about 59 microns. This so-called "trapped bubble" technique is well known in the art. The film was then rapidly cooled to set the orientation and then rolled up for further processing.
The polyvinylidene chloride and the ethylene-vinylacetate copolymer can alternatively be coated onto the substrate using a two-ply coextrusion die.
Thee test results are summarized in the following table II.
TABLE I
__________________________________________________________________________
A B D F
Exampe No.
sealing layer
μm
core layer
μm
barrier layer
μm
outer layer
μm
__________________________________________________________________________
Comp. 1
E/9% VA
37 -- PVDC B E/9% VA
14
Comp. 2
Ionomer (Na)
15 E/9% VA
22 PVDC 8 E/9% VA
14
Comp. 3
E/8% B 15 E/9% VA
22 PVDC 8 E/9% VA
14
Comp. 4
E/10.5% O
15 E/9% VA
22 PVDC 8 E/9% VA
14
1 E/15% B
15 E/9% VA
22 PVDC 8 E/9% VA
14
2 E/13% O
15 E/9% VA
22 PVDC 8 E/9% VA
14
3 E/19% O
15 E/9% VA
22 PVDC 8 E/9% VA
14
__________________________________________________________________________
TABLE II
__________________________________________________________________________
Example
Comparison 1
Comparison 2
Comparison 3
Comparison 4
Shrink Shrink Shrink Shrink
VPHB
% VPHB
% VPHB
% VPHB
%
##STR1##
##STR2##
##STR3##
##STR4##
##STR5##
##STR6##
##STR7##
##STR8##
##STR9##
__________________________________________________________________________
60° C. 4 2 2
70° C. 11 6 7
80° C.
663 21 856 25 855 12 930 14
85° C.
652 30 782 795 841
90° C.
520 41 608 45 644 24 695 28
95° C.
318 57 438 540 552
100° C. 268 63 420 42 432 49
COLD 24,5 15,8 16,1 17,3
SEAL
STRENGTH
(kg/6 cm)
(10% no.
breakage)
__________________________________________________________________________
Example
Example 1
Example 2
Example 3
Shrink Shrink Shrink
VPHB
% VPHB
% VPHB
%
##STR10##
##STR11##
##STR12##
##STR13##
##STR14##
##STR15##
##STR16##
__________________________________________________________________________
60° C.
3 2 4
70° C.
10 7 9
80° C.
1040
27 1051
16 1074
25
85° C.
940 928 990
90° C.
783 48 745 33 802 49
95° C.
647 558 621
100° C.
398 64 429 53 363 67
COLD 22,5 19,4 23,5
SEAL
STRENGTH
(kg/6 cm)
__________________________________________________________________________
When comparing the results it should be borne in mind that the shrink temperature should not exceed a value at which the hot-burst pressure drops below 650 mm/H2 O. For some food products the maximum shrink temperature may be more limited but a higher hot-burst will then give additional safety. It is clear from the data in table II that comparison 1 gives good cold seal strength but the hot seal strength and the percent shrink leave something to be desired. Further, this material results in poor seal strength through contamination like gease or blood. Comparision 2 shows improved shrink characteristics but the cold seal strength is considerably lower and this material cannot be sealed reliably through blood contamination.
Examples 1, 2 and 3 show that excellent shrink characteristics and a very good seal strength both at room temperature and at elevated temperatures are being obtained. It has further been found that the seal strength is not significantly affected by contamination like grease or blood. Comparisons 3 and 4 show that a very significant decrease both in seal strength and percent shrink occur when the comonomer content in the ethylene α-olefin copolymer drops below a certain level, i.e. the minimum comonomer content is an essential feature if the combination of desired properties is to be achieved.
Multi-layer packaging films of the composition summarized in the following table III were produced by conventional techniques, i.e. by coextruding a tubular film of layers A to F and subsequent stretching and orientation, e.g. in the blown-up bubble, so as to obtain a heat shrinkable film. No irradiation was employed in this case. The test results obtained are tabulated in the following table IV.
TABLE III
__________________________________________________________________________
C D E F
Example
A B adhesion barrier
adhesion outer
No. sealing layer
μm
core layer
μm
promotor
μm
layer
μm
promotor
μm
layer
μm
__________________________________________________________________________
Comp. 5
Ionamer (Na)
25 E/18% VA
9 +
acid modif.
6 PVDC
8 acid modif.
6 PA 23
E/14% VA
43 EVA EVA
Comp. 6
E/8% B 25 E/18% VA
9 +
acid modif.
6 PVDC
8 acid modif.
6 PA 23
E/14% VA
43 EVA EVA
4 E/15% B 25 E/18% VA
9 +
acid modif.
6 PVDC
8 acid modif.
6 PA 23
E/14% VA
43 EVA EVA
5 E/13% O 25 E/18% VA
9 +
acid modif.
6 PVDC
8 acid modif.
6 PA 23
E/14% VA
43 EVA EVA
6 E/19% O 25 E/18% VA
9 +
acid modif.
6 PVDC
8 acid modif.
6 PA 23
E/14% VA
43 EVA EVA
7 75% E/13% O +
25 E/18% VA
9 +
acid modif.
6 PVDC
8 acid modif.
6 PA 23
25% EBA E/14% VA
43 EVA EVA
8 90% E/13% O +
25 E/18% VA
9 +
acid modif.
6 PVDC
8 acid modif.
6 PA 23
10% acid modif.
E/14% VA
43 EVA EVA
EVA
9 50% E/13% O +
25 E/18% VA
9 +
acid modif.
6 PVDC
8 acid modif.
6 PA 23
50% E/8% VA E/14% VA
43 EVA EVA
10 50% F/15% B +
25 E/18% VA
9 +
acid modif.
6 PVDC
8 acid modif.
6 PA 23
50% P/4.5% E
E/14% VA
43 EVA EVA
__________________________________________________________________________
TABLE IV
__________________________________________________________________________
Example
Comparison 5
Comparison 6
Example 4 Example 5 Example 6
Shrink % Shrink % Shrink % Shrink % Shrink %
##STR17##
##STR18##
##STR19##
##STR20##
##STR21##
##STR22##
##STR23##
##STR24##
##STR25##
##STR26##
##STR27##
__________________________________________________________________________
60° C.
15 4,5 13,5 5 9
70° C.
25 9,5 21.5 11 19,5
80° C.
993 37 951 15,6 1084 33,5 1043 19 1007 33
85° C.
877 892 753
90° C.
617 43 857 30,6 835 45,0 710 36 560 43
95° C.
381 534 431
100° C.
319 46 599 42,0 546 55,0 436 51 338 51
COLD SEAL
17,6 25,6 32,7 29,6 28
STRENGTH (70% no.
(kg/6 cm) breakage)
__________________________________________________________________________
Example
Example 7 Example 8 Example 9 Example 10
Shrink % Shrink % Shrink % Shrink %
##STR28##
##STR29##
##STR30##
##STR31##
##STR32##
##STR33##
##STR34##
##STR35##
##STR36##
__________________________________________________________________________
60° C.
5 6 10 4
70° C.
12 13 16 10
80° C.
1020 18 980 20 940 20 1150 18
85° C.
850 780 720 810
90° C.
700 35 670 35 610 34 700 34
95° C.
525 510 470 560
100° C.
410 52 430 48 320 52 490 44
COLD SEAL
32,0 34 32 25
STRENGTH
(kg/6 cm)
__________________________________________________________________________
The results are essentially similar to those obtained with the irradiated material. Only the films of the present invention combine excellent shrink characteristics with outstanding cold and hot seal strength. In addition thereto they may be sealed without impairing the seal strength through contamination like grease or blood which are always encountered in the packaging of meat products. Further, the non-irradiated structures show the same effect, namely a strong dependency of the shrink and seal characteristics on the comonomer content of the ethylene/α-olefin copolymer.
Claims (7)
1. A multi-layer thermoplastic packaging film having improved heat shrink and cold seal properties, said film comprising:
(a) a first surface layer which is a heat sealing surface, said layer comprising:
(1) a copolymer of ethylene and an alpha-olefin having 4 to 8 carbon atoms per molecule; and,
(2) said copolymer comprising 90% to 75% ethylene and 10% to 25% alpha-olefin having 4 to 8 carbon molecules and a density of less than 915 kg/m3 ;
(b) a second surface layer, said layer comprising a polymer selected from the group consisting of amide polymers, ethylene/vinyl-acetate copolymers, the copolymer of the first layer, and ionomers;
(c) a first core layer comprising an ethylene/vinyl-acetate copolymer;
(d) a second core or barrier layer comprising a polymer selected from the group consisting of copolymers of vinylidene chloride and hydrolyzed copolymers of ethylene/vinyl-acetate;
(e) said core layers being internal film layers positioned between said first and second surface layers;
(f) at least one adhesive layer to promote adhesion of the barrier layer to another layer; and
(g) said film comprising at least five layers.
2. The film of claim 1 wherein the first surface layer is cross-linked.
3. The film of claim 1 wherein the first surface layer comprises a blend of the copolymer defined in (a) (1) and (2) with a copolymer selected from the group consisting of copolymers of ethylene/vinyl-acetate and copolymers of ethylene/butyl-acrylate.
4. The film of claim 1 wherein the second core or barrier layer comprises a vinylidene chloride copolymer and the second surface layer comprises a polyamide.
5. A bag formed from the film of claim 1. .Iadd.
6. A multi-layer, heat-shrinkable thermoplastic packaging film having excellent heat shrink and cold seal properties, said film comprising:
(a) a first surface layer which is heat-sealing, said first surface layer comprising a blend of (i) a linear copolymer of 90% to 75% ethylene and 10% to 25% of an alpha-olefin having 4 to 8 carbon atoms per molecule, said linear copolymer having a density of less than 915 kg/m3 and at least 906 kg/m3, and (ii) up to 50% by weight, based on the total weight of the first surface layer, of a polymer compatible with said linear copolymer selected from the group consisting of linear polyethylene copolymers having a density above 915 kg/m3, low density polyethylene, ethylene vinylacetate, acid-modified ethylene vinylacetate, polypropylene, copolymers of ethylene and propylene, ionomeric polymers and ethylene/alkylacrylate copolymers wherein the alkyl moiety has 1 to 8 carbon atoms; and
(b) a second surface layer comprising a polymer material selected from the group consisting of said linear copolymer of the first surface layer, ethylene-vinylacetate copolymers, polyamides and ionomeric resins. .Iaddend. .Iadd.7. A multi-layer, heat-shrinkable thermoplastic packaging film having excellent heat shrink and cold seal properties as recited in claim 6, said film further comprising:
(c) a first internal layer between said first surface layer and said second surface layer, said first internal layer comprising a core or barrier material. .Iaddend. .Iadd.8. A multi-layer, heat-shrinkable thermoplastic packaging film having excellent heat shrink and cold seal properties as recited in claim 7, said film further comprising:
(d) a second internal layer between said first internal layer and said second surface polymer layer, said second internal layer comprising a core or barrier material. .Iaddend. .Iadd.9. A multi-layer, heat-shrinkable thermoplastic packaging film having excellent heat shrink and cold seal properties as recited in claim 8, wherein said core or barrier materials of said first and second internal layers are selected from the group consisting of copolymers of ethylene vinylacetate and polyvinylidene chloride copolymers. .Iaddend. .Iadd.10. A multi-layer, heat-shrinkable thermoplastic packaging film having excellent heat shrink and cold seal properties as recited in claim 8, further comprising:
(e) an adhesive layer between said first surface layer and said second surface layer. .Iaddend. .Iadd.11. A multi-layer, heat-shrinkable thermoplastic packaging film having excellent heat shrink and cold seal properties as recited in claim 10, wherein said at least one adhesive layer contains acid-modified ethylene vinylacetate. .Iaddend. .Iadd.12. A multi-layer, heat-shrinkable thermoplastic packaging film having excellent heat shrink and cold seal properties as recited in claim 8, wherein the core or barrier material of said first internal layer contains a copolymer of ethylene vinylacetate and the core or barrier material of said second internal layer contains polyvinylidene chloride. .Iaddend. .Iadd.13. A multi-layer, heat-shrinkable thermoplastic packaging film having excellent heat shrink and cold seal properties as recited in claim 12, further comprising:
(e) an adhesive layer between said first internal layer and said second internal layer; and
(f) an adhesive layer between said second internal layer and said second surface layer. .Iaddend. .Iadd.14. A multi-layer, heat-shrinkable thermoplastic packaging film having excellent heat shrink and cold seal properties as recited in claim 13, wherein said adhesive layers contain acid-modified ethylene vinylacetate. .Iaddend. .Iadd.15. A multi-layer, heat-shrinkable thermoplastic packaging film having excellent heat shrink and cold seal properties as recited in claim 7, wherein said first surface layer is cross-linked. .Iaddend. .Iadd.16. A multi-layer, heat-shrinkable thermoplastic packaging film having excellent heat shrink and cold seal properties as recited in claim 6, wherein in the heat-sealing blend, said polymer compatible with the linear copolymer is selected from the group consisting of copolymers of ethylene vinylacetate, acid-modified ethylene vinylacetate, copolymers of ethylene and propylene, and ethylene-butylacrylate. .Iaddend. .Iadd.17. A bag formed from the film according to claim 16. .Iaddend. .Iadd.18. A multi-layer, heat-shrinkable thermoplastic packaging film having excellent heat shrink and cold seal properties, said film comprising:
(a) an inner layer comprising a heat-sealing blend of (i) a linear copolymer of ethylene and x to y % by weight, based on the linear copolymer, of an alpha-olefin having 4 to 8 carbon atoms per molecule, wherein x=0.5nC +8 and y=1.25nC +15 with nC being the number of carbon atoms in the alpha-olefin, said linear copolymer having a density of less than 915 kg/m3 and at least 906 kg/m3, and (ii) up to 50% by weight, based on the total weight of the heat-sealing inner layer, of a polymer compatible with said linear copolymer selected from the group consisting of linear polyethylene copolymers having a density above 915 kg/m3, low density polyethylene, ethylene vinylacetate, acid modified ethylene vinylacetate, polypropylene, copolymers of ethylene and propylene, ionomeric polymers and ethylene/alkylacrylate copolymers wherein the alkyl moiety has 1 to 8 carbon atoms; and
(b) an outer layer comprising a polymer material selected from the group consisting of said linear copolymer of the inner layer, ethylene-vinylacetate copolymers, polyamides and ionomeric resins. .Iaddend. .Iadd.19. A multi-layer, heat-shrinkable thermoplastic packaging film having excellent heat shrink and cold seal properties as recited in claim 18, wherein in the heat-sealing blend, said polymer compatible with the linear copolymer is selected from the group consisting of copolymers of ethylene vinylacetate, acid-modified ethylene vinylacetate, copolymers of ethylene and propylene, and ethylene-butylacrylate. .Iaddend. .Iadd.20.
A bag formed from the film according to claim 18. .Iaddend. .Iadd.21. A thermoplastic multilayer packaging film having superior heat shrink and cold seal properties comprising at least an outer polymer layer and an inner heat sealing layer, said heat sealing layer comprising a linear copolymer of ethylene and x to y % by weight, based on the copolymer, of an alpha-olefin with 4 to 8 carbon atoms per molecule, wherein x=0.5nc+8 and y=1.25nc+15 with nc being the number of carbon atoms in the alpha-olefin, said copolymer having a density of less than 0.915 g/cc and at least 0.906 g/cm3. .Iaddend.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/085,468 USRE35285E (en) | 1985-09-30 | 1993-06-30 | Thermoplastic multi-layer packaging film and bags made therefrom |
Applications Claiming Priority (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT22305/85 | 1985-09-30 | ||
| IT22305/85A IT1190394B (en) | 1985-09-30 | 1985-09-30 | THERMOPLASTIC MULTI-LAYER FILM FOR PACKAGING AND BAGS |
| IT8620457A IT1207999B (en) | 1986-05-16 | 1986-05-16 | Thermoplastic multilayer packaging film |
| IT20457/86 | 1986-05-16 | ||
| US06/911,936 US4801486A (en) | 1985-09-30 | 1986-09-26 | Thermoplastic multi-layer packaging film and bags made therefrom |
| US64848091A | 1991-01-30 | 1991-01-30 | |
| US08/085,468 USRE35285E (en) | 1985-09-30 | 1993-06-30 | Thermoplastic multi-layer packaging film and bags made therefrom |
Related Parent Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US06/911,936 Reissue US4801486A (en) | 1985-09-30 | 1986-09-26 | Thermoplastic multi-layer packaging film and bags made therefrom |
| US64848091A Continuation | 1985-09-30 | 1991-01-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| USRE35285E true USRE35285E (en) | 1996-06-25 |
Family
ID=27452817
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US08/085,468 Expired - Lifetime USRE35285E (en) | 1985-09-30 | 1993-06-30 | Thermoplastic multi-layer packaging film and bags made therefrom |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | USRE35285E (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6099682A (en) | 1998-02-09 | 2000-08-08 | 3M Innovative Properties Company Corporation Of Delaware | Cold seal package and method for making the same |
| US6212062B1 (en) | 1998-09-29 | 2001-04-03 | General Electric Company | Sealed ultracapacitor |
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| US6287613B1 (en) | 1994-12-12 | 2001-09-11 | Cryovac Inc | Patch bag comprising homogeneous ethylene/alpha-olefin copolymer |
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Citations (42)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3456044A (en) * | 1965-03-12 | 1969-07-15 | Heinz Erich Pahlke | Biaxial orientation |
| US3808304A (en) * | 1964-03-18 | 1974-04-30 | Grace W R & Co | Oriented blends of polypropylene and polybutene-1 |
| US4011382A (en) * | 1975-03-10 | 1977-03-08 | Union Carbide Corporation | Preparation of low and medium density ethylene polymer in fluid bed reactor |
| JPS52135386A (en) * | 1976-05-08 | 1977-11-12 | Gunze Kk | Laminated film with good low temperature heat seal property |
| US4064296A (en) * | 1975-10-02 | 1977-12-20 | W. R. Grace & Co. | Heat shrinkable multi-layer film of hydrolyzed ethylene vinyl acetate and a cross-linked olefin polymer |
| US4076698A (en) * | 1956-03-01 | 1978-02-28 | E. I. Du Pont De Nemours And Company | Hydrocarbon interpolymer compositions |
| EP0002606A1 (en) * | 1977-12-14 | 1979-06-27 | Mobil Oil Corporation | Oriented polypropylene with linear low density polyethylene copolymer coating |
| US4161562A (en) * | 1976-12-29 | 1979-07-17 | Kureha Kagaku Kogyo Kabushiki Kaisha | Biaxially stretched five-layer film for packaging food |
| US4196240A (en) * | 1978-01-18 | 1980-04-01 | Union Carbide Corporation | Heat shrinkable multilayer packaging film of blended copolymers and elastomers |
| US4207363A (en) * | 1978-03-29 | 1980-06-10 | Union Carbide Corporation | Flexible heat-shrinkable multilayer film for packaging primal meat |
| US4239826A (en) * | 1978-12-28 | 1980-12-16 | American Can Company | Multi-layer barrier film |
| US4254169A (en) * | 1978-12-28 | 1981-03-03 | American Can Company | Multi-layer barrier film |
| GB2066274A (en) * | 1979-12-26 | 1981-07-08 | Nippon Oil Co Ltd | Copolymerisation of ethylene and alpha -olefines in vapour phase |
| US4281045A (en) * | 1979-11-29 | 1981-07-28 | Kyoraku Co., Ltd. | Multi-layer extruded article |
| US4302565A (en) * | 1978-03-31 | 1981-11-24 | Union Carbide Corporation | Impregnated polymerization catalyst, process for preparing, and use for ethylene copolymerization |
| US4330639A (en) * | 1979-12-26 | 1982-05-18 | Nippon Oil Company, Ltd. | Polymer blend composition for forming polyethylene film |
| US4335224A (en) * | 1980-02-29 | 1982-06-15 | Nippon Oil Company, Limited | Polymer compositions comprising ethylene polymer blends |
| US4339181A (en) * | 1980-03-04 | 1982-07-13 | Datagraphix, Inc. | Lens arrangements for microfiche reader assembly and method |
| GB2097324A (en) * | 1981-04-23 | 1982-11-03 | Du Pont | Shrink films of ethylene/ alpha - olefin copolymers |
| JPS5837907A (en) * | 1981-08-31 | 1983-03-05 | アンリツ株式会社 | Method of producing anodic oxidized aluminum humidity sensitive film |
| JPS5882752A (en) * | 1981-11-11 | 1983-05-18 | 呉羽化学工業株式会社 | Heat-shrinkable film |
| JPS58102762A (en) * | 1981-12-15 | 1983-06-18 | 旭化成株式会社 | Low-temperature heat-shrinkable multilayer barrier film and its manufacture |
| US4399181A (en) * | 1978-12-18 | 1983-08-16 | Asahi-Dow Limited | Cold drawn high-orientation multilayered film and process for manufacture of said film |
| JPS58208435A (en) * | 1982-05-31 | 1983-12-05 | 昭和電工株式会社 | Packing cloth |
| US4424243A (en) * | 1979-12-25 | 1984-01-03 | Kureha Kagaku Kogyo Kabushiki Kaisha | Heat-shrinkable laminate film |
| US4429079A (en) * | 1980-08-07 | 1984-01-31 | Mitsui Petrochemical Industries, Ltd. | Ethylene/alpha-olefin copolymer composition |
| US4438238A (en) * | 1981-01-30 | 1984-03-20 | Sumitomo Chemical Company, Limited | Low density copolymer composition of two ethylene-α-olefin copolymers |
| US4447480A (en) * | 1982-12-01 | 1984-05-08 | Union Carbide Corporation | Shrinkable film for poultry bags |
| US4456646A (en) * | 1980-10-31 | 1984-06-26 | Kureha Kagaku Kogyo Kabushiki Kaisha | Laminate film having a heat-shrinkage rate greater than 15 percent at 90° C. |
| US4457960A (en) * | 1982-04-26 | 1984-07-03 | American Can Company | Polymeric and film structure for use in shrink bags |
| US4469742A (en) * | 1983-01-31 | 1984-09-04 | W. R. Grace & Co., Cryovac Div. | Pasteurizable, cook-in shrink film |
| EP0120503A1 (en) * | 1983-03-29 | 1984-10-03 | Union Carbide Corporation | Preparation of low density, low modulus ethylene copolymers in a fluidized bed |
| US4508842A (en) * | 1983-03-29 | 1985-04-02 | Union Carbide Corporation | Ethylene polymerization using supported vanadium catalyst |
| US4542886A (en) * | 1977-10-11 | 1985-09-24 | Y. Toyoda International Patent Office | Process for preparing cold drawn film from an ethylene-α-olefin copolymer and at least one of low-density polyethylene or ethylene copolymers and polypropylene, high density polyethylene or crystalline polybutadiene |
| US4640856A (en) * | 1985-04-29 | 1987-02-03 | W. R. Grace & Co., Cryovac Div. | Multi-layer packaging film and receptacles made therefrom |
| US4755436A (en) * | 1986-06-30 | 1988-07-05 | W. R. Grace & Co., Cryovac Div. | Inter-ply adhesion between saran and linear ethylene copolymers |
| US4863784A (en) * | 1987-05-28 | 1989-09-05 | Viskase Corporation | Multilayer film containing very low density polyethylene |
| US4863769A (en) * | 1985-06-17 | 1989-09-05 | Viskase Corporation | Puncture resistant, heat-shrinkable films containing very low density polyethylene |
| US4894107A (en) * | 1985-05-16 | 1990-01-16 | American National Can Company | Process for making multiple layer polymeric films |
| US4976898A (en) * | 1985-06-17 | 1990-12-11 | Viskase Corporation | Process for making puncture resistant, heat-shrinkable films containing very low density polyethylene |
| US4988783A (en) * | 1983-03-29 | 1991-01-29 | Union Carbide Chemicals And Plastics Company Inc. | Ethylene polymerization using supported vanadium catalyst |
| US5059481A (en) * | 1985-06-17 | 1991-10-22 | Viskase Corporation | Biaxially stretched, heat shrinkable VLDPE film |
-
1993
- 1993-06-30 US US08/085,468 patent/USRE35285E/en not_active Expired - Lifetime
Patent Citations (47)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4076698A (en) * | 1956-03-01 | 1978-02-28 | E. I. Du Pont De Nemours And Company | Hydrocarbon interpolymer compositions |
| US4076698B1 (en) * | 1956-03-01 | 1993-04-27 | Du Pont | |
| US3808304A (en) * | 1964-03-18 | 1974-04-30 | Grace W R & Co | Oriented blends of polypropylene and polybutene-1 |
| US3456044A (en) * | 1965-03-12 | 1969-07-15 | Heinz Erich Pahlke | Biaxial orientation |
| US4011382A (en) * | 1975-03-10 | 1977-03-08 | Union Carbide Corporation | Preparation of low and medium density ethylene polymer in fluid bed reactor |
| US4064296A (en) * | 1975-10-02 | 1977-12-20 | W. R. Grace & Co. | Heat shrinkable multi-layer film of hydrolyzed ethylene vinyl acetate and a cross-linked olefin polymer |
| JPS52135386A (en) * | 1976-05-08 | 1977-11-12 | Gunze Kk | Laminated film with good low temperature heat seal property |
| GB1600250A (en) * | 1976-12-29 | 1981-10-14 | Kureha Chemical Ind Co Ltd | Multilayer shrink-wrapping film and method for preparing same |
| US4161562A (en) * | 1976-12-29 | 1979-07-17 | Kureha Kagaku Kogyo Kabushiki Kaisha | Biaxially stretched five-layer film for packaging food |
| US4542886A (en) * | 1977-10-11 | 1985-09-24 | Y. Toyoda International Patent Office | Process for preparing cold drawn film from an ethylene-α-olefin copolymer and at least one of low-density polyethylene or ethylene copolymers and polypropylene, high density polyethylene or crystalline polybutadiene |
| EP0002606A1 (en) * | 1977-12-14 | 1979-06-27 | Mobil Oil Corporation | Oriented polypropylene with linear low density polyethylene copolymer coating |
| US4196240A (en) * | 1978-01-18 | 1980-04-01 | Union Carbide Corporation | Heat shrinkable multilayer packaging film of blended copolymers and elastomers |
| US4207363A (en) * | 1978-03-29 | 1980-06-10 | Union Carbide Corporation | Flexible heat-shrinkable multilayer film for packaging primal meat |
| US4302565A (en) * | 1978-03-31 | 1981-11-24 | Union Carbide Corporation | Impregnated polymerization catalyst, process for preparing, and use for ethylene copolymerization |
| US4469753A (en) * | 1978-12-18 | 1984-09-04 | Asahi-Dow Limited | Cold drawn high-orientation multilayered film and process for manufacture of said film |
| US4399181A (en) * | 1978-12-18 | 1983-08-16 | Asahi-Dow Limited | Cold drawn high-orientation multilayered film and process for manufacture of said film |
| US4239826A (en) * | 1978-12-28 | 1980-12-16 | American Can Company | Multi-layer barrier film |
| US4254169A (en) * | 1978-12-28 | 1981-03-03 | American Can Company | Multi-layer barrier film |
| US4281045A (en) * | 1979-11-29 | 1981-07-28 | Kyoraku Co., Ltd. | Multi-layer extruded article |
| US4424243A (en) * | 1979-12-25 | 1984-01-03 | Kureha Kagaku Kogyo Kabushiki Kaisha | Heat-shrinkable laminate film |
| US4330639A (en) * | 1979-12-26 | 1982-05-18 | Nippon Oil Company, Ltd. | Polymer blend composition for forming polyethylene film |
| GB2066274A (en) * | 1979-12-26 | 1981-07-08 | Nippon Oil Co Ltd | Copolymerisation of ethylene and alpha -olefines in vapour phase |
| US4335224A (en) * | 1980-02-29 | 1982-06-15 | Nippon Oil Company, Limited | Polymer compositions comprising ethylene polymer blends |
| US4339181A (en) * | 1980-03-04 | 1982-07-13 | Datagraphix, Inc. | Lens arrangements for microfiche reader assembly and method |
| US4429079A (en) * | 1980-08-07 | 1984-01-31 | Mitsui Petrochemical Industries, Ltd. | Ethylene/alpha-olefin copolymer composition |
| US4456646A (en) * | 1980-10-31 | 1984-06-26 | Kureha Kagaku Kogyo Kabushiki Kaisha | Laminate film having a heat-shrinkage rate greater than 15 percent at 90° C. |
| US4438238A (en) * | 1981-01-30 | 1984-03-20 | Sumitomo Chemical Company, Limited | Low density copolymer composition of two ethylene-α-olefin copolymers |
| GB2097324A (en) * | 1981-04-23 | 1982-11-03 | Du Pont | Shrink films of ethylene/ alpha - olefin copolymers |
| JPS5837907A (en) * | 1981-08-31 | 1983-03-05 | アンリツ株式会社 | Method of producing anodic oxidized aluminum humidity sensitive film |
| JPS5882752A (en) * | 1981-11-11 | 1983-05-18 | 呉羽化学工業株式会社 | Heat-shrinkable film |
| US4547433A (en) * | 1981-11-11 | 1985-10-15 | Kureha Kagaku Kogyo Kabushiki Kaisha | Heat-shrinkable laminate film |
| JPS58102762A (en) * | 1981-12-15 | 1983-06-18 | 旭化成株式会社 | Low-temperature heat-shrinkable multilayer barrier film and its manufacture |
| US4457960A (en) * | 1982-04-26 | 1984-07-03 | American Can Company | Polymeric and film structure for use in shrink bags |
| JPS58208435A (en) * | 1982-05-31 | 1983-12-05 | 昭和電工株式会社 | Packing cloth |
| US4447480A (en) * | 1982-12-01 | 1984-05-08 | Union Carbide Corporation | Shrinkable film for poultry bags |
| US4469742A (en) * | 1983-01-31 | 1984-09-04 | W. R. Grace & Co., Cryovac Div. | Pasteurizable, cook-in shrink film |
| EP0120503A1 (en) * | 1983-03-29 | 1984-10-03 | Union Carbide Corporation | Preparation of low density, low modulus ethylene copolymers in a fluidized bed |
| US4508842A (en) * | 1983-03-29 | 1985-04-02 | Union Carbide Corporation | Ethylene polymerization using supported vanadium catalyst |
| US4988783A (en) * | 1983-03-29 | 1991-01-29 | Union Carbide Chemicals And Plastics Company Inc. | Ethylene polymerization using supported vanadium catalyst |
| US4640856A (en) * | 1985-04-29 | 1987-02-03 | W. R. Grace & Co., Cryovac Div. | Multi-layer packaging film and receptacles made therefrom |
| US4894107A (en) * | 1985-05-16 | 1990-01-16 | American National Can Company | Process for making multiple layer polymeric films |
| US4863769A (en) * | 1985-06-17 | 1989-09-05 | Viskase Corporation | Puncture resistant, heat-shrinkable films containing very low density polyethylene |
| US4976898A (en) * | 1985-06-17 | 1990-12-11 | Viskase Corporation | Process for making puncture resistant, heat-shrinkable films containing very low density polyethylene |
| US5059481A (en) * | 1985-06-17 | 1991-10-22 | Viskase Corporation | Biaxially stretched, heat shrinkable VLDPE film |
| US4755436A (en) * | 1986-06-30 | 1988-07-05 | W. R. Grace & Co., Cryovac Div. | Inter-ply adhesion between saran and linear ethylene copolymers |
| US4863784A (en) * | 1987-05-28 | 1989-09-05 | Viskase Corporation | Multilayer film containing very low density polyethylene |
| US4863784C1 (en) * | 1987-05-28 | 2001-05-01 | Bt Commercial Corp | Multilayer film containing very low density polyethylene |
Non-Patent Citations (71)
| Title |
|---|
| "Can `VLDPE` outperform EVA, other copolymers?", Modern Plastics International, Oct. 1984, pp. 6, 8. |
| "Cast Film", DSM. |
| "Currents", Chemical Engineering, Oct. 15, 1984, p. 42. |
| "Design Parameters for LLDPE Film Resin Selection", Polymers, Lamination and Coatings Conference, TAPPI, 1984. |
| "Introducing `Very Low Density PE`", Plastics Technology, Sep. 1984, p. 113. |
| "Now it's very-low-density polyethylene", Chemical Week, Sep. 19, 1984, p. 66. |
| "Plastiscope", Modern Plastics Encyclopedia. |
| "Polyethylene producers face tough times," European Chemical News, Dec. 16, 1985, pp. 13-14. |
| "Programme for the International Agents Meeting," DSM Polymers International, Mar. 26-30, 1984. |
| "Sclair® 11P and 11W Polyethylene Resins," Du Pont Company, Oct. 1980. |
| "Sclair® Linear Polyethylene Film Resins," Du Pont Canada Inc., printed Jan. 1983. |
| "Stamylex Film Grades", DSM Polymers International. |
| "Stamylex PE", Dutch State Mining, Feb. 1984. |
| "TAFMER(R)", Mitsui Petrochemical Industries, Ltd., Aug. 1975. |
| "TAFMER® . . . A new-type elastomer as Plastics Modifying Agent, supplied in pellet form," dated Aug. 1975. |
| "TAFMER® `A`--A New Polyolefin Resin With Excellent Flexibility," dated Jan. 1977. |
| "TAFMER® `P`--A new-type elastomer as Plastics Modifying Agent, supplied in pellet form," dated Aug. 1975. |
| "TAFMER®", Mitsui Petrochemical Industries, Ltd. |
| "Technical Information on TAFMER® A and TAFMER® P Plastics Modifiers," Mitsui Petrochemical Industries, Ltd. |
| "Technical Information--Dowlex™ 2088 Linear Low Density Polyethylene For Cast Film Extrusion," The Dow Chemical Company, copyright 1981, May 23, 1984. |
| "Technical Information--Dowlex™ 4000 Linear Low Density Polyethylene," The Dow Chemical Company, Oct. 16, 1985. |
| "Technical Information--Dowlex™ 4088 Linear Low Density Polyethylene," The Dow Chemical Company, Mar. 14, 1985. |
| "Technical Information--XU-61502.43 Linear Low Density Polyethylene," The Dow Chemical Company, Jan. 22, 1986. |
| "Technical Information--XU-61512.01 Linear Low Density Polyethylene For Blown Film Extrusion," The Dow Chemical Company, Dec. 5, 1984. |
| "UC researchers smash 0.915 PE density mark", Plastics World, Oct. 1984, p. 8. |
| "Ultralow density PEs are tough, flexible, versatile", Plastics World, Oct. 1984, p. 86. |
| "XP-61512.00 Linear Low Density Polyethylene For Cast Film Extrusion," The Dow Chemical Co., copyright 1984. |
| Can VLDPE outperform EVA, other copolymers , Modern Plastics International, Oct. 1984, pp. 6, 8. * |
| Cast Film , DSM. * |
| Currents , Chemical Engineering, Oct. 15, 1984, p. 42. * |
| Design Parameters for LLDPE Film Resin Selection , Polymers, Lamination and Coatings Conference, TAPPI, 1984. * |
| F. Karol, "The polyethylene revolution," Chemtech, Apr. 1983, pp. 222-228. |
| F. Karol, The polyethylene revolution, Chemtech, Apr. 1983, pp. 222 228. * |
| Introducing Very Low Density PE , Plastics Technology, Sep. 1984, p. 113. * |
| J. P. Machon, "Actual and Potential Development of High Pressure Process for Linear Polyethylene," Polyethylenes 1933-83, The Plastics and Rubber Institute Golden Jubilee Conference, Jun. 8-10, 1983, pp. B2.5.1-B2.5.8. |
| J. P. Machon, Actual and Potential Development of High Pressure Process for Linear Polyethylene, Polyethylenes 1933 83, The Plastics and Rubber Institute Golden Jubilee Conference, Jun. 8 10, 1983, pp. B2.5.1 B2.5.8. * |
| L. Chriswell, "Modern Processes for the Manufacture of Polyethylene and Polypropylene," Chemical Engineering Progress, Apr. 1983, pp. 84-92. |
| L. Chriswell, Modern Processes for the Manufacture of Polyethylene and Polypropylene, Chemical Engineering Progress, Apr. 1983, pp. 84 92. * |
| M. Concha, "Polyethylene, Linear Low-Density," Packaging Engineering, Jan. 1983, pp. 76-78. |
| M. Concha, Polyethylene, Linear Low Density, Packaging Engineering, Jan. 1983, pp. 76 78. * |
| Mitsui Petrochemical in Perspective, Mitsui Petrochemical Industries, Ltd., 1984. * |
| New Kind of Polyethylene Combines Flexibility, Toughness, Heat Resistance, Plastics Technology, Oct. 1984, pp. 13 and 15. * |
| Now it s very low density polyethylene , Chemical Week, Sep. 19, 1984, p. 66. * |
| Packaging, Jan. 1985, pp. 57 60. * |
| Packaging, Jan. 1985, pp. 57-60. |
| Plastiscope , Modern Plastics Encyclopedia. * |
| Polyethylene producers face tough times, European Chemical News, Dec. 16, 1985, pp. 13 14. * |
| Programme for the International Agents Meeting, DSM Polymers International, Mar. 26 30, 1984. * |
| S. Kurtz, "VLDPE plugs a gap in PE's density spectrum," Plastics Engineering, Sep. 1985, pp. 59-62. |
| S. Kurtz, "VLDPE: A Breakthrough in Flexible Linear Polyethylene," ANTEC '85, pp. 463-465. |
| S. Kurtz, VLDPE plugs a gap in PE s density spectrum, Plastics Engineering, Sep. 1985, pp. 59 62. * |
| S. Kurtz, VLDPE: A Breakthrough in Flexible Linear Polyethylene, ANTEC 85, pp. 463 465. * |
| Sclair 11P and 11W Polyethylene Resins, Du Pont Company, Oct. 1980. * |
| Sclair Linear Polyethylene Film Resins, Du Pont Canada Inc., printed Jan. 1983. * |
| Stamylex Film Grades , DSM Polymers International. * |
| Stamylex PE , Dutch State Mining, Feb. 1984. * |
| TAFMER , Mitsui Petrochemical Industries, Ltd. * |
| TAFMER . . . A new type elastomer as Plastics Modifying Agent, supplied in pellet form, dated Aug. 1975. * |
| TAFMER A A New Polyolefin Resin With Excellent Flexibility, dated Jan. 1977. * |
| TAFMER P A new type elastomer as Plastics Modifying Agent, supplied in pellet form, dated Aug. 1975. * |
| TAFMER(R) , Mitsui Petrochemical Industries, Ltd., Aug. 1975. * |
| Technical Information Dowlex 2088 Linear Low Density Polyethylene For Cast Film Extrusion, The Dow Chemical Company, copyright 1981, May 23, 1984. * |
| Technical Information Dowlex 4000 Linear Low Density Polyethylene, The Dow Chemical Company, Oct. 16, 1985. * |
| Technical Information Dowlex 4088 Linear Low Density Polyethylene, The Dow Chemical Company, Mar. 14, 1985. * |
| Technical Information on TAFMER A and TAFMER P Plastics Modifiers, Mitsui Petrochemical Industries, Ltd. * |
| Technical Information XU 61502.43 Linear Low Density Polyethylene, The Dow Chemical Company, Jan. 22, 1986. * |
| Technical Information XU 61512.01 Linear Low Density Polyethylene For Blown Film Extrusion, The Dow Chemical Company, Dec. 5, 1984. * |
| UC researchers smash 0.915 PE density mark , Plastics World, Oct. 1984, p. 8. * |
| Ultralow density PEs are tough, flexible, versatile , Plastics World, Oct. 1984, p. 86. * |
| Union Carbide, Presentation for Cryovac, Sep. 1984. * |
| XP 61512.00 Linear Low Density Polyethylene For Cast Film Extrusion, The Dow Chemical Co., copyright 1984. * |
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