WO1994023945A1 - Evoh oxygen barrier stretched multilayer film - Google Patents
Evoh oxygen barrier stretched multilayer film Download PDFInfo
- Publication number
- WO1994023945A1 WO1994023945A1 PCT/US1994/004051 US9404051W WO9423945A1 WO 1994023945 A1 WO1994023945 A1 WO 1994023945A1 US 9404051 W US9404051 W US 9404051W WO 9423945 A1 WO9423945 A1 WO 9423945A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- film
- melt index
- adhesive
- layer
- layers
- Prior art date
Links
Classifications
-
- 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
-
- 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
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/04—Interconnection of layers
- B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
-
- 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
- B32B2307/00—Properties of the layers or laminate
- B32B2307/30—Properties of the layers or laminate having particular thermal properties
- B32B2307/31—Heat sealable
-
- 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
- B32B2307/00—Properties of the layers or laminate
- B32B2307/50—Properties of the layers or laminate having particular mechanical properties
- B32B2307/514—Oriented
- B32B2307/518—Oriented bi-axially
-
- 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
- B32B2307/00—Properties of the layers or laminate
- B32B2307/70—Other properties
- B32B2307/724—Permeability to gases, adsorption
- B32B2307/7242—Non-permeable
- B32B2307/7244—Oxygen barrier
-
- 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
- B32B2307/00—Properties of the layers or laminate
- B32B2307/70—Other properties
- B32B2307/732—Dimensional properties
- B32B2307/734—Dimensional stability
- B32B2307/736—Shrinkable
-
- 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
- Y10S428/91—Product with molecular orientation
-
- 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.]
- Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
- Y10T428/1379—Contains vapor or gas barrier, polymer derived from vinyl chloride or vinylidene chloride, or polymer containing a vinyl alcohol unit
- Y10T428/1383—Vapor or gas barrier, polymer derived from vinyl chloride or vinylidene chloride, or polymer containing a vinyl alcohol unit is sandwiched between layers [continuous layer]
-
- 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
- Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
- Y10T428/24942—Structurally defined web or sheet [e.g., overall dimension, etc.] including components having same physical characteristic in differing degree
- Y10T428/2495—Thickness [relative or absolute]
-
- 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
- Y10T428/26—Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
- Y10T428/263—Coating layer not in excess of 5 mils thick or equivalent
-
- 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
- Y10T428/31739—Nylon type
- Y10T428/31743—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]
-
- 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
Definitions
- This invention relates to biaxially stretched heat shrinkable multilayer films with an EVOH-based oxygen barrier core layer, as for example used in food packaging.
- Thermoplastic films have been used for many years in connection with packaging of various articles including food products such as fresh red meat.
- the latter is often in the form of large pieces (primal cuts) which are placed in bags formed of thermoplastic films which are evacuated and sealed as for example by heating the opposite surfaces of the bag at the open mouth end and pressing the inner surfaces together to form a heat seal.
- the resulting food-containing packages are often shipped from the packing house to supermarkets or retail butchers where the packages are opened and the primal cuts divided into smaller pieces for retail packaging. These food-containing packages must provide an oxygen- free environment for substantial periods such as 4-8 weeks, so the film packaging art has provided multilayer films with a core layer which is an oxygen barrier material .
- the most commonly used oxygen barrier materials are vinylidene chloride copoiy ⁇ ner ⁇ with various comonomers such as vinyl chloride (VC-VDC copolymer. or methyl acrylate (MA-VDC copolymer).
- Other known oxygen barrier materials include polyamides and ethylene vinyl alcohol copolymer (EVOH) .
- thermoplastic film has several other requirements as for example resistance to abuse and stress during packaging and handling, an attractive uniform appearance with no streaks, and good optical properties so that the valuable food product such as a fresh red meat primal cut may be periodically visually inspected to insure that the package integrity has not been lost. Accordingly, good optical properties include low haze and high gloss.
- thermoplastic film must provide high abuse resistance because the food-containing packages are often moved several times in the shipping-distribution chain and subjected to external abuse and impact. Also, the inside surface usually must be heat sealable to itself, and since different heat sealing apparatus often operate at different temperatures.
- the inside surface must be heat sealable over a wide temperature range .
- thermoplastic films for packaging oxygen sensitive products such as fresh red meat
- MD machine direction
- TD transverse direction
- the food-containing film package may be evacuated with the film inner wall collapsing against the food product outer surface, and thereafter heated as for example by hot water spray in a tunnel to heat shrink the collapsed film and provide a tight package.
- thermoplastic films commonly have at least three layers; the aforementioned core-barrier layer, an abuse resistant layer on one side of the core layer and a heat sealing layer on the other side of the core layer.
- a commonly used multilayer film for packaging fresh red meat has been a three layer type comprising a vinylidene chloride copolymer barrier layer and polyolefin layers on opposite sides, most commonly polyethylene-ethylene vinyl acetate (EVA) blend abuse and heat sealing layers.
- the preferred polyethylenes are very low density polyethylene (VLDPE) which is also called ultra low density polyethylene (ULDPE), and linear low density polyethylene (LLDPE).
- Irradiative crosslinking is commonly said to improve the puncture resistance of the polyethylene in the inner and outer layers, or improve the tensile strength of the EVA in the inner layer to permit biaxial orientation by forming a stable bubble of the primary tube, or to widen the heat sealing range of the inner layer, or a combination of the above.
- VC-VDC copolymer is irradiated at doses in the order of 5 MR, the material partially degrades and develops a yellowish tint which is aesthetically unpleasing.
- EVOH has been known for many years as a suitable oxygen barrier material, and in fact is
- cook-in systems wherein the fresh food body is placed in a bag which is evacuated and sealed. The package is then placed in a hot water bath and the food body cooked insitu. After cooking the package is cooled and stored at low temperature until ready for use.
- these cook-in packages need not be heat shrinkable to the extent required in the fresh red meat market, and are not subjected to the physical abuse experienced by fresh red meat packages.
- EVOH-based oxygen barrier layer films have not been widely used in commerce for the packaging, storing and shipping of fresh red meat.
- One reason is that EVOH is far more sensitive to moisture contact than vinylidene chloride copolymers.
- EVOH has not been widely used as an oxygen barrier layer in thermoplastic bags for packaging fresh red meat
- its adhesion properties to polyethylene-EVA blends are substantially inferior to vinylidene chloride copolymers. Whereas the latter may be adhered directly to polyethylene-EVA blends with sufficient strength to withstand delamination forces during heat shrink, this has not been possible with EVOH-based oxygen barrier layers. Instead, it has been necessary to add additional layers between the barrier layer and the abuse or heat sealing layers.
- These extra layers are known as adhesive or tie layers and perform a function of interlayer adhesion between the EVOH layer and the (outer) abuse resistant layer or the (inner) heat sealing layer in the bag formed from the multilayer thermoplastic film.
- the materials forming these adhesive layers are chemically complex, as for example
- polyethylene-based modified maleic anhydride types hence expensive. Moreover they add to the complexity and expense of the manufacturing process.
- multilayer films comprises between about 8 and 20% of the total film thickness, and is the most expensive material in the film.
- An object of this invention is to provide a biaxially stretched heat shrinkable multilayer film with an EVOH-based oxygen barrier layer, and having physical properties at least equivalent to vinylidene chloride copolymer barrier layer films currently used to package fresh red meat .
- Another object is to provide such an EVOH-based barrier layer type film with a barrier layer
- a further object is to provide such an EVOH-based barrier layer type film having fewer than six layers.
- a still further object is to provide such an EVOH-based barrier layer type film with at least
- U.S. Patent No. 4,407,897 to Farrell et al describes a multilayer film comprising an EVOH core layer, intermediate modified polyolefin adhesive layers, and polyolefin outer layers.
- multilayer film comprising an EVOH-polyamide blend core layer, intermediate adhesive layers formed of carboxylic acid modified polyethylene, and EVA-LLDPE blend outer layers.
- multilayer film comprising a 0-50% polyamide eg. nylon 6,66 and 50-100% EVOH core layer, intermediate adhesive layers formed of olefinic polymers having carboxyl modifications, and outer layers comprising 40-100% EVA and 0-60% LLDPE.
- U.S. Patent No. 4,615,926 to Hsu et al describes a multilayer film comprising an EVOH-polyamide core layer, olefin based adhesive intermediate layers, an ionomer inner layer and a polyethylene outer layer.
- U.S. Patent No. 4,758,463 to Vicik describes a three layer biaxially stretched heat shrinkable film suitable for meat cook-in applications, having an EVOH-polyamide core layer and outer layers comprising a blend of EVA and an EVA anhydride functionally adhesive
- This type film is not suitable for use in fresh red meat packaging because of its relatively low puncture resistance and relatively high cost EVOH core layer.
- U.S. Patent No. 4,851,290 to Vicik discloses a three layer irradiated film for holding hot-filled foods during the succeeding cold water tumble-chilling and further refrigerating steps, comprising a nylon 6,12 or nylon 6,66 core layer, and outer layers comprising a blend of 50-75% polyethylene or EVA and 25-50%
- U.S. Patent No. 4,857,399 to Vicik describes a four layer biaxially stretched heat shrinkable film suitable for nonadhering meat cook-in applications, having an EVOH-polyamide core barrier layer, a blend of EVA and anhydride-modified ethylene copolymer adhesive as an outer abuse layer on one side of the barrier layer, an EVA-anhydride-modified ethylene copolymer blend as a layer on the other side of the barrier core layer, and an inner or meat contacting layer comprising an ethylenepropylene random copolymer.
- This type film is not suitable for use in fresh red meat packaging because of its relatively poor optical properties and relatively low shrink.
- U.S. Patent No. 5,004,647 to Shah describes a biaxially stretched heat shrinkable film having an 80-99% EVOH and 1-20% polyamide blend core layer, intermediate adhesive layers for example formed of anhydride-modified polyethylene, and three component blend outer layers of LLDPE, linear medium density polyethylene (LMDPE) and EVA.
- LLDPE linear medium density polyethylene
- U.S. Patent No. 5,075,143 to Bekele describes a nine layer film having an EVOH core layer, intermediate EVA layers, adhesive layers formed of chemically modified polyolefin, and moisture resistant layers formed of ionomer or VLDPE.
- the outer layers are a VLDPE sealant layer on the inside, and a heat resistant HDPE layer on the outside.
- This invention is a biaxially oriented heat shrinkable multilayer film prepared by the double bubble process and having at least five layers : an oxygen barrier core layer, second and third intermediate
- the adhesive layers directly adhered to opposite sides of the core layer, a self heat sealable fourth outer layer directly adhered to the side of the second intermediate adhesive layer opposite the core layer, and an abuse-resistant fifth outer layer directly adhered to the side of the third intermediate adhesive layer opposite the core layer.
- the fourth outer layer is on the inside and when there are only five layers it is in direct contact with the stored product, and the fifth outer layer is on the outside in direct contact with the surrounding environment when there are only five layers.
- the oxygen barrier core layer comprises a polymer blend having a relatively high weighted average melting point.
- the blend comprises between about 70 and about 85 wt . % ethylene vinyl alcohol (EVOH) and between about 15 and about 30 wt.% nylon 6,66 copolymer.
- the EVOH has a melting point of about 162°C to about 178°C.
- the nylon 6,66 copolymer has a melting point within about 35°C of the EVOH melting point.
- the polymer blend has a relatively high average melting point.
- the core layer has a thickness of between about 0.05 and about 0.1 mil and provides an oxygen barrier such that the oxygen permeability through the film is below about 35 cc/m 2 /24 hours (2.26 cc/l00 in 2 /24 hours). This permeability is measured at 1 atm. and 23°C for the thickness of film tested.
- the second and third intermediate adhesive layers each comprise a blend of between about 35 and about 80 wt.% very low density polyethylene and between about 20 and about 40 wt.% of either polyethylene-based modified anhydride adhesive having a melt index below about 1.7 or EVA-based modified anhydride adhesive having a melt index below about 0.5. These layers may also contain between 0 and about 40 wt.% ethylene vinyl acetate having fractional melt index and between about 7 and about 15 wt.% vinyl acetate content.
- the two or three component blend (s) have fractional average melt indexes, and also relatively low average melting points below the average melting point of said polymer blend of the core layer.
- the second and third intermediate adhesive layers each comprise between about 2.5 and about 5% of the film thickness.
- the self heat sealable fourth layer (which becomes the inner layer of a bag formed from the film) comprises one or more thermoplastic polymers with the EVA content of the layer between 0 and about 45 wt.%.
- This layer has a fractional melt index and a relatively low melting point below the average melting point of the core layer polymer blend.
- This fourth outer layer comprises between about 40% and about 70% of the film thickness.
- the abuse-resistant fifth outer layer (which becomes the outer layer of a bag formed from the film) comprises one or more thermoplastic polymers with the EVA content of the layer between 0 and about 45 wt.%. This layer has a fractional melt index, and also a relatively low melting point below the average melting point of the core layer polymer blend.
- the fifth outer layer comprises between about 20% and about 35% of the film thickness.
- At least one of the fourth and fifth outer layers has a melting point of at least about 105°C.
- either or both fourth and the fifth outer layer comprises a blend of polyolefins
- the above-described relationships are based on the average melt index of the blend.
- the above-described relationships are based on the average melting point of the blend.
- the film of this invention also has at least 30% free shrink at 90°C in the transverse direction, and a total thickness of between about 1.5 and 3.5 mils.
- the instant film accomplishes all of the aforedescribed objects.
- its physical properties are at least equivalent to vinylidene chloride copolymer barrier layer films currently used to package fresh red meat.
- the inventive film has an EVOH-based barrier layer which is substantially thinner than known EVOH type multilayer films proposed for fresh red meat packaging. This film requires no more than five layers, and has at least equivalent optical properties to PVDC barrier type multilayer films currently used for fresh red meat packages. Also this film has the
- Figures 1 and 2 are logarithmic graphs of melt index versus percent of the higher melt index polymer in blends. Detailed Description of the Invention
- the multilayer film of this invention is "biaxially stretched heat shrinkable". As used herein this means that the film has an
- thermoplastic film For purposes of measuring the shrink value of a thermoplastic film and comparing it with these
- the unrestrained shrink of the film is measured by a procedure derived from ASTM D2732 after immersion in a water bath at 90°C for five seconds.
- Four test specimens are cut from a given sample of the film to be tested. The specimens are cut to 10 cm. in the machine direction by 10 cm. in the transverse direction. Each specimen is completely immersed for 5 seconds in a 90°C water bath. After removal from the water bath the distance between the ends of the specimen is measured. The difference in the measured distance for the shrunken specimen and the original 10 cm. is multiplied by ten to obtain the percent of shrinkage for the specimen.
- the shrinkage for the four specimens is averaged for the MD shrinkage values of the given film sample, and the shrinkage for the four specimens is averaged for the TD shrinkage value.
- melt index is an important physical characteristic of the layer, it is defined in terms of "average melt index". For a given polymer blend this average is determined from Figures 1 and 2 which are logarithmic graphs of melt index on one axis (eg. the ordinate) and percent of the higher melt index polymer in the blend, on the other axis (eg. the abscissa).
- the melt index of the constituent polymers are measured according to the procedure outlined in ASTM D 1238 at 190°C unless specified otherwise and in grams per 10 minutes. The steps in this procedure for
- the average melt index of a blend of two of the components is determined as described above.
- the average melt index of these two components is then plotted on the graph versus the third component as described in steps 1 and 2 above. From the straight line connecting the two points, the average melt index of the three component blend can be determined from the point on the line which corresponds to the percent of the highest index component (s) in the blend. If the average melt index of the two component blend is higher than that of the third component, the two component average melt index is employed as the percent of the highest melting component in the blend and plotted accordingly.
- the blend comprises 40 wt.% EVA having a melt index of 0.25 and 60% LLDPE-based anhydride modified adhesive having a melt index of 2.0.
- the EVA melt index is located as a point on the left side ordinate scale corresponding to 0% adhesive.
- the adhesive melt index is located as a point on the right side ordinate scale corresponding to 100% adhesive.
- the two points are connected as a straight line.
- the average melt index of the blend is determined by locating a point on this line which corresponds to 60 wt . % adhesive on the abscissa, i.e. about 0.88 gms/10 min.
- the blend comprises 52.5% VLDPE having a melt index of 0.5, 17.5 wt.% EVA having a melt index of 0.25, and 30% LLDPE-based anhydride modified adhesive having a melt index of 0.8.
- the EVA melt index is located as a point on the left side ordinate scale corresponding to 0% adhesive.
- the VLDPE melt index is located as a point on the right side ordinate scale corresponding to 100%
- VLDPE on the abscissa, i.e. about 0.42 gms/10 min.
- This value is located as a point on the left side ordinate scale corresponding to 0% adhesive.
- the adhesive melt index is located as a point on the right side ordinate scale corresponding to 100% adhesive (0.8).
- the two points are connected as a straight line.
- the average melt index of the three component blend is determined by locating a point on this line which corresponds to 30% adhesive on the abscissa, i.e. 0.50 gms/10 min.
- melt point is an important physical characteristic of the layer, it is defined in terms of "average melting point". For a given polymer blend this is calculated by adding the product of the individual polymer's melting point and its blend fraction, i.e. polymer 1 melting point times its blend fraction plus polymer 2 melting point times its blend fraction plus the corresponding factor for any other components in the blend.
- fractional means that the melt index of a single polymer or the average melt index of a polymer blend does not exceed about 1.
- carrier or “barrier layer” as used herein mean a layer of a multilayer film which acts as a physical barrier to gaseous oxygen molecules.
- a barrier layer material will reduce the oxygen permeability of a film (used to form the bag) to less than 70 cc per square meter in 24 hours at one atmosphere, 73°F (23°C) and 0% relative humidity. These values should be measured in accordance with ASTM
- ethylene vinyl acetate copolymer refers to a copolymer formed from ethylene and vinyl acetate monomers wherein the ethylene derived units (monomer units) in the
- copolymer are present in major amounts (by weight) and the vinyl acetate derived units (monomer units) in the copolymer are present in minor, by weight, amounts.
- VLDPE very low density polyethylene
- ULDPE ultra low density polyethylene
- VLDPE linear low density polyethylene
- ULDPE ultra low density polyethylene
- VLDPE linear low density polyethylene
- LLDPE linear low density polyethylenes
- VLDPE comprises copolymers (including terpolymers) of ethylene with alpha-olefins, usually 1-butene, 1-hexene or 1-octene, and in some instances terpolymers, as for example of ethylene, 1-butene and 1-hexene .
- a process for making VLDPEs is described in European Patent Document publication number 120,503 whose text and drawing are hereby incorporated by reference into the present document.
- VLDPEs are capable of use in biaxially
- Suitable VLDPEs include those manufactured by Dow Chemical Company, Exxon Chemical Company and Union Carbide Corporation, and having the following physical properties in the resin form according to the
- EVOH is prepared by the hydrolysis (or
- the EVOH component of the oxygen barrier core layer has a melting point between about 162°C and about 178°C. This is characteristic of EVOH materials having ethylene content of between about 38 mol% and about 44 mol%. It has been discovered that when used in the core layer polymer blend, EVOH materials with melting points below this range result in core layers which do not have sufficient oxygen barrier properties to produce a satisfactory heat shrinkable product with a thin core layer. For this reason, EVOH materials with about 48 mol% and higher ethylene content (resulting in melting points below about 162°F) are unsuitable for practicing this invention, as will be demonstrated in Example 1 (sample 1).
- EVOH materials also differ in melt index, even with the same ethylene content.
- 38 mol% ethylene type EVOH is commercially available with melt indexes of 3 to 8 g/10 min (measured at 190°C per ASTM D 1238).
- melt index is not a limitation in selecting suitable EVOH materials, the higher melt indexes are preferred because the resulting film softens and stretches more easily during biaxial orientation.
- an 8.4 melt index 38 mol% ethylene-type EVOH is preferred for use in the polymer blend of the multilayer film core layer.
- nylon 6,66 is a copolymer of nylon 6 and nylon 66. Nylon 6 is
- Nylon 66 is the polymer derived from adipic acid and hexamethyiene diamine.
- Nylon 6,66 is manufactured by different companies, in some instances with different percentages of the two monomers, possibly by different methods and presumably with different operating parameters. Accordingly, the properties of various nylon 6,66 copolymers may differ significantly. For example, the melting temperature decreases as the nylon 66 content, is increased from 5% to 20 mol %.
- Example 2 when other nylons such as type 6,12 are used as the polyamide in the polymer blend of the oxygen barrier layer, gels develop in the core layer of the five layer film and in some instances cracks develop.
- the gels may be due to EVOH-nylon 6,12 incompatibility or chemical reaction between the two polymers.
- the cracks probably develop because the polymer blend is not stretching uniformly during the orientation.
- Table C The physical properties of representative nylons are summarized in Table C.
- the oxygen barrier core layer comprises a polymer blend of between about 70 and about 85 wt. % EVOH, and between about 15 and about 30 wt. % nylon 6,66. If less than about 15 wt.% nylon 6,66 is used, the core layer tends to crack (sometimes referred to as "line-drawing") rather than stretch uniformly during biaxial orientation. This is in part because EVOH is relatively brittle. Also EVOH can only be stretched over a relatively narrow temperature range. More than about 30 wt.% nylon should not be used in the core layer polymer blend, because the oxygen barrier quality of the blend declines to an unacceptable level.
- a polymer blend between about 78 and 82% EVOH and about 18 and 22% nylon 6,66 is
- a variety of ethylene vinyl acetates having fractional melt indexes may be used in at least the second and third intermediate adhesive layers, and having vinyl acetate contents between about 7 and about 15% of the copolymer total weight. Lower VA contents than this range are too stiff and inelastic. Higher VA contents tend to be excessively soft. Vinyl acetate contents in the range of 8-12 wt.% are preferred from the standpoint of processability and strength.
- Suitable EVAs include those listed in Table D. Since the at least five layer film of this invention requires that at least one of the fourth and fifth outer layers has a melting point of at least 105°C, it will be apparent from Table D (and demonstrated in Example 2, Table G) that both of these layers cannot comprise 100% of these EVAs (discussed hereinafter).
- the second and third intermediate adhesive layers are bonded to opposite sides of the oxygen barrier core layer, and each comprise a blend of two essential components: 35-80 wt. fractional melt index VLDPE, and 20-40% of either: (a) polyethylene- based modified anhydride adhesive with melt index less than about 1.7, or (b) EVA-based modified anhydride adhesive with melt index less than about 0.5.
- a third optional component is 0 to about 40 wt.% fractional melt index EVA having between about 7 and about 15 wt.% vinyl acetate content.
- the two or three component blend (s) comprising the second and third intermediate adhesive layers have a fractional average melt index and also a average melting point below that of the core layer polymer blend.
- Table E is a partial list of anhydride modified ethylene copolymer-based adhesives used in the ensuing examples .
- the five layer film of this invention may be manufactured by extrusion of all layers simultaneously i.e. coextruded as for example described in Schirmer U.S. Patent No. 4,448,792 or in steps i.e. by the coating lamination procedure described in Brax et al U.S. Patent No. 3,741,253 to form a relatively thick primary film either as a flat sheet or as a tube, most commonly the latter.
- This primary and relatively thick film is biaxially oriented by the well-known trapped bubble or double bubble technique as for example described in
- the film is preferably biaxially oriented wherein
- transverse (TD) orientation is accomplished by inflation to radially expand the heated film.
- Machine direction (MD) orientation is preferably accomplished with the use of nip rolls rotating at different speeds to pull or draw the film tube in the machine direction.
- the stretch ratio in the biaxial orientation to form the bag material is sufficient to provide a film with total thickness of between about 1.5 and 3.5 mils.
- the MD stretch ratio is typically 3-5 and the TD stretch ratio is also typically 3-5.
- An overall stretch ratio (MD stretch multiplied by TD stretch) of about 9x-25x is suitable.
- the preferred method for forming the multilayer film is coextrusion of the primary tube which is then biaxially oriented in the manner broadly described in the aforementioned Pahlke Patent.
- all five layers were coextruded and the primary tube was cooled. It was then partially reheated with radiant heaters and further heated to the draw temperature for biaxial orientation by an air cushion which had itself been heated by transverse flow through a heated porous tube concentrically positioned around the moving primary tube. It has been determined that during biaxial orientation relatively low blow ratios provide higher shrink values than relatively high blow ratios when preparing the five layer film of this invention.
- irradiation with an electron beam at dosage levels of at least about 1 megarad (MR) and preferably in the range of 3-5 MR, although higher dosages may be employed. Irradiation may be done on the primary tube or after biaxial orientation. The latter, called post-irradiation, is preferred and described in Lustig et al U.S. Patent No. 4,737,391.
- An advantage of post-irradiation is that a relatively thin film is treated instead of the relatively thick primary tube, thereby reducing the power requirement for a given treatment level.
- preorientation is that a relatively thin film is treated instead of the relatively thick primary tube, thereby reducing the power requirement for a given treatment level.
- irradiation is that if the practitioner is using a barrier layer material which tends to discolor on
- cross linking may be achieved by addition of a cross linking enhancer to one or more of the layers, as for example described in Evert et al U.S. Patent No. 4,055,328.
- the most commonly used cross linking enhancers are organic peroxides such as
- the five layer film of this invention has a very thin EVOH-nylon 6,66 blend core layer thickness of between about 0.05 and about 0.1 mil yet provides an oxygen permeability of less than about 35 cc/m 2 /24 hours.
- the latter is the performance level required for shrink packaging fresh red meat.
- This has been accomplished with a substantially thinner barrier layer containing the relatively expensive EVOH than heretofore proposed films of this type.
- the total thickness of the film is between about 1.5 and about 3.5 mils, the same as the conventional multilayer oxygen-moisture barrier films currently used in fresh red meat packaging.
- the second and third adhesive layers of this film are the next most expensive components, and they each comprise only between about 2 . 5 and 5% of the film thickness .
- the fourth outer layer of the film becomes the inner layer of a bag formed from the film, and is in direct contact with the packaged meat product.
- This layer comprises between about 40% and about 70% of the film thickness and as the thickest layer provides the bulk for the necessary shrink properties.
- the inner surface of this fourth layer is also self heat sealable, i.e. the inner surfaces are sealed together after
- the thickness of this bag inner layer must comprise at least about 40% of the total thickness of the film to prevent burn through during heat sealing.
- the fourth layer should not comprise more than about 70% of the film thickness because the fifth layer (which becomes the outer layer of the bag) must have sufficient bulk for abuse and puncture resistance from outside contact.
- the fifth layer comprises between about 20% and about 35% of the film thickness.
- the fourth layer is too thin to perform the above-described functions of the bag inner layer.
- the EVOH-nylon 66 blend barrier core layer of this film has a relatively high average melting point. In this context "relatively high" refers to the
- These relatively low melting points must be sufficiently low for the film to shrink at least 30% at 90°C in the transverse direction and preferably at least 20% in the machine direction. This is a requirement for shrinking the meat-containing evacuated and sealed bag against the meat outer surface by movement through the conventional hot water-heated shrink tunnel .
- the second and third intermediate layers were 53% DEFD 1192 type VLDPE, 30% Plexar 3741 adhesive and 17% DQDA 6833 type EVA, and the weighted average melting point was 116°C.
- the fourth outer layer was 100% DQDA 6833 type EVA and the fifth outer layer was 76.5% DQDA 6833 type EVA, 19.1% DFFD 1192 type VLDPE and 4.4% processing aid.
- the second and third intermediate layers were 52.5% Attane XU 61509.32 type VLDPE, 30% Plexar 3779 adhesive and 17.5% DQDA 6833 type EVA and their -average melting point was 116°C.
- the fourth and fifth outer layers were 70.6% DEFD 1192 type VLDPE, 25% DQDA 6833 type EVA and 4.4% processing aid. Their average melt index was 0.25g/l0 min, and their weighted average melting point was 115°C.
- Sample 3 with the same nylon as sample 2 but with a substantially higher melt index type EVOH from the same manufacturer (8.4 vs. 3.8), provided better
- Sample 6 included 44% ethylene type EVOH, a relatively low melting point EVOH embodiment of the invention, i.e. 164°C.
- Sample 1 with 48% ethylene type EVOH and a 158°C melting point provided satisfactory optical, shrink and strength properties but the oxygen transmission rate was substantially higher than the lower ethylene content - higher melting point EVOH samples, and unacceptably high for commercial use.
- the differences between the sample 1 and sample 2-6 second through fifth layers do not affect the relative oxygen transmission rates of these samples.
- This data supports the about 44% ethylene upper limit and 162°C melting point lower limit for the EVOH in the multilayer film oxygen barrier core layer of this invention.
- samples 2-6 are invention embodiments wherein the average melting points of the core layer are higher than the other layers, and fourth and fifth outer layers have about the same melting points as the second and third intermediate adhesive layers. These values are as follows: 179°C (core layer), 116°C (adhesive layers) and 115°C (outer layers).
- the adhesive and outer layers have fractional melt indexes.
- the EVOH melting point range of 162-178°C is substantially above that of PVDC, the most commonly used oxygen barrier in multilayer films for fresh red meat packaging; the vinylidene chloride copolymers melt at about 148°-150°C. Since the higher melting EVOH is relatively inflexible at the substantially lower
- the barrier layer is a blend of between about 70 and about 85 wt.% EVOH and between about 15 and about 30 wt.% nylon 6, 66. Higher EVOH content does not provide sufficient flexibility and higher nylon 6, 66 content reduces the barrier properties to an unacceptable level for the intended use.
- a preferred balance of these considerations is a core blend of between about 78 and about 82 wt.% EVOH and between about 12 and about 18 wt.% nylon 6, 66.
- Table G shows that none of the nylon 6 , 12 containing core layer films had satisfactory optical properties (samples 7, 8 and 10). This was possibly due to a partial reaction between the nylon and EVOH, or a mixing or incompatibility phenomena, resulting in severe gels.
- samples 3 and 6 with nylon 6,66 were optically superior with no gels, notwithstanding the use of different types of EVOH in the core layer (38 and 44 mol % ethylene respectively).
- Samples 2 and 3 each included the same type nylon 6,66, but the former was only fair from an optical standpoint because it had a few gels. In contrast sample 3 had no gels and was optically
- the second and third intermediate adhesive layers of Table G samples were 30% Plexar 169 adhesive and 70% DQDA 6833 type EVA (samples 7-9), 60% Admer 500 adhesive and 40% DQDA 6833 type EVA (sample 10), 52.5% Attane 61509.32, 17.5% DQDA 6833 type EVA and 30% Plexar 3779 adhesive (samples 2 and 3) or 30% Plexar 3741 (sample 6), and 30% Plexar 169 adhesive and 70% DQDA 6833 type EVA
- sample 11 Their average melt indexes (g/10 min) were: 0.51 (samples 7-9), 0.86 (sample 10), 0.46 (samples 2, 3), 0.54 (sample 6) and 0.51 (sample 11). Their average melting points (in °C) were: 100° (samples 7-9), 111o
- Example 10 116° (samples 2,3 and 6), and 101° (sample 11).
- Table G illustrates that the nylon in the oxygen barrier core layer of the inventive five layer film must be nylon 6,66.
- optical properties of five layer films of this invention with oxygen barrier core layers having the same percent ethylene-type EVOH and nylon 6,66 are not necessarily the same.
- samples 2, 9 and 11 have the same type EVOH comprising 80% of the core layer, and 20% nylon 6,66, but samples 9 and 11 have 100% EVA with no VLDPE in their outer layers.
- the sample 2 outer layers comprise 75% VLDPE and 25% EVA.
- the optical properties of sample 2 are much better than samples 9 and 11. The reasons for this difference are not fully understood but may be related to the higher extrusion and biorientation temperatures required when higher melting VLDPE is blended in the outer layers with the lower melting EVA. This higher
- either or both the fourth and fifth layers of the inventive film must have a melting point of at least about 105°C, so both layers cannot comprise 100% EVA.
- sample 2 adhesive is a fractional melt index material (Plexar 3779) whereas the samples 9 and 11 adhesive material (Plexar 169) has a melt index of 2.5.
- melt index of the adhesive should be below about 1.7. This provides the adhesive layer with enough strength to support the stretching forces during the orientation process.
- samples 2, 3 and 6 are embodiments of the invention wherein the average melting points of the core (first) layer, the second and third intermediate adhesive layers and the fourth and fifth outer layers are progressively lower, i.e. for samples 2 and 3 they are 180°C, 116° and 115°C and for sample 6 they are 171°C, 116° and 115°C.
- the second and third intermediate adhesive layers, and the fourth and fifth outer layers have fractional melt indexes.
- Film samples 7, 8 and 10 are optically unsatisfactory because nylon 6, 66 was not used in the core layer.
- Film samples 9 and 11 are
- thicknesses (in mils) for these samples were: 2.45 (sample 12), 2.49 (sample 13), 2.88 (sample 14), 2.49 (sample 15), 2.51 (sample 16) and 2.84 (sample 19). Accordingly, the core layer thicknesses were in the range of 0.07-0.09 mil.
- the core layer for all film samples was 80% EVOH H 103 and 20% nylon 1539, having an average melting point of 116°C.
- the second and third intermediate adhesive layers for all films were 52.5% Attane type 61509.32 VLDPE, 30% Plexar 3779 adhesive and 17.5% DQDA 6833 type EVA, their average melt index was 0.46 g/10 min. and their average melting point was 116°C. In addition to optical ⁇ , certain physical properties were measured. The data is summarized in Table H.
- biaxially oriented EVA film When measured under equivalent conditions, biaxially oriented EVA film provides higher shrink in each of the transverse and machine directions than biaxially oriented VLDPE film, although VLDPE has substantially higher heat shrink than linear low density polyethylene
- Table H shows that the film optical properties (haze and gloss) become poorer with increasing EVA
- the preferred balance of properties with EVA-VLDPE blend fourth and fifth outer layers is between about 25% and about 40% EVA, and between about 60% and about 75% VLDPE.
- the fourth and fifth-outer layers each comprise a blend of between about 65 and about 72 wt.% VLDPE of about 0.912 density and about 0.19 melt index (DEFD type 1192), and between about 22 and about 28 wt.% EVA having about 10% vinyl acetate content.
- samples 12-17 are invention embodiments wherein the average melting point of the core layer is higher than the other layers and the fourth and fifth outer layers have slightly lower melting points than the second and third intermediate adhesive layers.
- the core layer and adhesive layer melting points were 179°C and 116°C respectively.
- the outer layers of these samples have fractional melt indexes. The 45% EVA concentration limit in the outer layers is
- VLDPE materials can be used in the fourth and fifth outer layers of the five layer film of this invention.
- six different VLDPE materials were used in the fourth and fifth outer layers of samples 18-23 in blends with 25% EVA (10% vinyl acetate) and 4.4% processing aid. Since the adhesive and oxygen barrier core layers were
- Table I shows that four of the VLDPE 's gave similar results in terms of physical properties, ie.
- Sample 20 was a blend of 50%
- Attane 61590.32 (comprising the only VLDPE in successful sample 19), and Attane 61512.21.
- the shrink was suitable, the other physical properties were somewhat lower than the single component VLDPE films.
- sample 18 which had only Attane 61512.21 as its outer layer VLDPE, could not be manufactured because of low melt strength at the 400°F die temperature. That is, a stable bubble could not be maintained. So this
- VLDPE material is unsuitable for use in the outer layers of the instant film with this particular formulation to form a heat shrinkable film by double bubble biaxial orientation.
- the oxygen barrier core layer was 80% EVAL H101 type EVOH and 20% nylon 1539; the second and third adhesive layers were 52.5% Attane XU 61509.32 VLDPE, 30% Plexar 3779 adhesive and 17.59% DQDA 6833 type EVA. Samples 19-23 are embodiments of the invention.
- the thicknesses in mils (and percentages of the total film thickness) for the first to fifth layers were as follows:
- the oxygen barrier core layer comprised 20% nylon 1539 and 80% EVAL H101 type EVOH (samples 19-21), 80% H103 type EVOH (sample 22), and 80% Soarnol 3808 type EVOH (sample 23), and each had an average melting point of -179°C (340°F).
- the second and third intermediate adhesive layers were 52.5% VLDPE, 30% adhesive and 17.5% EVA.
- the VLDPE was Attane XU 61509.32 (samples 19-21), DEFD 1192 (sample 22) and Attane XU 61520.01 (sample 23).
- the adhesive was Plexar 3779 (samples 19-21) and Plexar 3741 (samples 22 and 23).
- the EVA was DQDA 6833 in all samples.
- the average melt indexes (in g/10 min) were as follows: 0.46 (samples 19-21), 0.62 (sample 22) and 0.89 (sample 23).
- the average melting point (in °C) was 116°C for each of samples 19-23.
- the average melt indexes (in g/10 min) were as follows: 0.4 (sample 19), 0.55 (sample 20), 0.71 (sample 21), 0.21 (sample 22), and 0.71 (sample 23).
- invention embodiment samples 19-21 and 23 have second and third intermediate adhesive layers, and fourth and fifth outer layers with substantially the same average melting points which are below the (first) core layer melting point.
- the second and third adhesive layers comprise a two or three component blend including between about 35% and about 80% VLDPE. These layers must have a fractional melt index to provide the adhesive layer with sufficient strength to withstand stretching the film during elevated temperature biaxial orientation. For the same reason, the second and third layers must have a
- VLDPE fractional average melt index
- the second and third intermediate layers comprise blends with between about 20% and about 40% by wt . adhesive component. Less than 20% does not provide the required adhesion between adjacent layers for the film. Greater than 40% adhesive increases the average melt index of these layers to a level where they do not have sufficient strength during the orientation process to support the film. In a preferred embodiment reflecting these considerations the adhesive component comprises between about 25% and 35% of the second and third intermediate adhesive layers.
- the second and third intermediate layers contain 0 to about 40% EVA with vinyl acetate content of 7 to 15 wt.%. If present, this constituent increases the shrink properties of the film compared to a two component blend. On the other hand EVA has lower strength at the orientation temperature than VLDPE, and for this reason should not exceed about 40 wt.% of the layers. As a preferred balance, EVA is present in a concentration of between about 10 and about 20 wt.%.
- substantially identical outer layers comprising 70.6% VLDPE, 25% EVA (10% vinyl acetate) and 4.4% processing aid with average melt index of 0.25 and average melting point of 115°C.
- the oxygen barrier core layers were identical and comprised 80% EVOH (EVAL H 103) and 20% nylon 6,66 (Allied type 1539).
- the only difference of substance between samples 24-32 was the adhesive layer. With the exception of sample 24 all samples included 30 wt.% adhesive component in the second and third layers. Optical properties were observed visually and the shrink was measured. The results of these tests are summarized in Table J which is best understood by reference to Table E identifying each of the adhesives used in samples 24-32.
- the inventive film is suitable for packaging fresh red meat, so must have good optical properties, ie. few visual stress lines, low haze and high gloss.
- Sample 28 was marginally acceptable with few stress lines, and the adhesive layers included 30% Plexar 3779 which is an LLDPE -based maleic anhydride modified copolymer (melt index 0.81).
- Sample 29 was very similar to sample 28, the only difference being the use of Dow type 61509.32 VLDPE in the adhesive and outer layers instead of Union Carbide's type 1192 VLDPE. There were no visual stress lines in sample 29, so its optical properties were superior to sample 28. With one exception (sample 32), sample 31 was the only other film which was without stress lines and its adhesive component was Plexar 3741, a low density polyethylene-based maleic anhydride
- the adhesive layers of samples 28, 29 and 31 comprised 49% VLDPE/17% EVA/30% adhesive and 4% processing aid, and as will be apparent from the ensuing discussion, they are the only invention embodiments in Table J. Accordingly in a preferred embodiment the second and third adhesive layers comprise a blend of between about 48 and about 55 wt.% very low density polyethylene of fractional melt index, between about 15 and about 22 wt.% ethylene vinyl acetate of about 0.25 melt index and 10% vinyl acetate content, and between about 25 and about 35 wt.% low density polyethylene based maleic anhydride modified adhesive.
- the thickness in mils (and percentages of the total film thickness) for the first to fifth layers of samples 28, 29 and 31 were as follows:
- the oxygen barrier core layer for samples 24-32 was 80% EVAL type H101 EVOH and 20% nylon 1539 with an average melting point of 179°C.
- Sample 24 included Admer 500 as the adhesive; Table E identifies this material as an LLDPE-based maleic anhydride modified copolymer with a relatively high melt index of 2.0. Because of this high value, the film had a substantial number of stress lines and would be optically unsuitable for the intended use of the inventive film. In contrast, otherwise similar film with Plexar 3741 polyethylene-based modified anhydride adhesive (melt index 1.5) such as sample 31 has good optical properties. Accordingly, to be useful in this invention such
- polyethylene based adhesives should have a melt index below about 1.7 g/10 min. This insures that the adhesive layer has sufficient strength during the orientation process to support the film. Higher melt indexes cannot withstand the stress under these conditions. For the same reason, the adhesive layer blend of the invention film must have an average melt index which is fractional.
- Sample 25 included a 70% Surlyn 1650-30% Plexar 106 adhesive layer; the latter is an EVA-based maleic anhydride copolymer with 1.2 MI.
- the film had a
- Sample 26 also contained 30% Plexar 106 as the adhesive component and had a relatively high melt index EVA base (1.2). This sample exhibited an objectionable number of stress lines.
- Sample 27 contained 30% Bynel CXA 3048 as the adhesive, and is identified as an EVA-based terpolymer with 0.9 melt index (Table E) . Despite this low MI and a fractional melt index adhesive layer, the film had a substantial number of stress lines in the machine
- Sample 30 contained 30% Plexar 169 as the adhesive; this copolymer is a low density polyethylene based maleic anhydride modified material with 2.5 melt index (ref. Table E). The sample displayed a substantial number of stress lines in the machine direction, so is unsuitable for the purposes of the present invention.
- melt index of EVA-based adhesives useful in this invention must be extremely low, i.e. below about 0.5 g/10 min.
- sample 31 the average melting points progressively decline from the core layer to the second-third intermediate adhesive layers to the fourth-fifth outer layers.
- each of these samples have fractional melt index adhesive layers and each has at least 30% free shrink at 90°C in the transverse
- the shrink levels were typically about 31% in the machine direction and about 39% in the transverse direction, both measured at 90°C. This is satisfactory for most fresh red meat packaging applications, but it would be desirable to provide even higher shrink levels for certain end uses of the instant five layer film.
- thermoplastic polymers This may be accomplished by employing different thermoplastic polymers in either or both the outer layers, and was demonstrated by two higher shrink
- Samples 33-35 are invention embodiments with identical oxygen barrier core layers: 80% EVAL H 103 type EVOH and 20% nylon type 1539.
- the core layer's polymer blend average melting point was 164°C.
- the intermediate second and third adhesive layers of samples 33 and 34 are identical, and sample 35 is very similar. Their average melt index was 0.61 g/10 min and their average melting point was 116°C.
- sample 33 were the aforedescribed VLDPE-EVA blend with an average melting point of 115°C, and this film provides average shrink properties for fresh red meat packaging.
- the sample 34 outer layers comprised a three component blend of VLDPE, EVA and an ethylene alpha olefin plastomer-type copolymer which was Mitsui 's Tafmer 1085 (melting point 71°C).
- Table K shows this film to have substantially higher shrink properties than average shrink sample 33.
- melt index of the outer layers was 0.25, below the corresponding value of 0.61 for the adjacent intermediate layers.
- 100°C average melting point of the outer layers was below the corresponding value of 116°C for the adjacent
- At least one of the fourth and fifth outer layer comprises a blend of between about 40 and about 60% VLDPE, between about 5 and about 20 wt.% pla ⁇ tomeric ethylene alpha olefin copolymer, and between about 20 and about 40 wt.% ethylene vinyl acetate having between about 7 and about 15 wt.% vinyl acetate content.
- the fourth outer layer (which would be the inner layer of a bag converted from the film) comprised 100% Surlyn 1706 ionomer, manufactured by DuPont Company and the fifth outer layer (which would be the outer layer of a bag) was identical to the outer layers of regular shrink film (110°C average melting point). Table K shows this film to also have
- sample 36 was a competitive six layer heat shrinkable film with an EVOH core layer.
- the film was W. R. Grace's type BB4-E which has been proposed for packaging fresh red meat.
- Table K shows that the heat shrink of inventive embodiment samples 34 and 35 are at least equivalent or even
- One preferred high shrink embodiment of the invention has fourth and fifth outer layers each
- plastomer having density of about 0.88, melt index of about 1.4 gms/10 min, and about 71°C melting point.
- Another preferred high shrink embodiment of the invention has an ionomer as at least one constituent of the fourth outer layer.
- the latter may for example comprise a blend of EVA and ionomer, or as in sample 36 the fourth outer layer may comprise 100% ionomer.
- Table L shows that on the basis of shrink, dynamic puncture and oxygen permeability comparisons, the inventive five layer films are at least comparable to the vinylidene chloride copolymer-type three layer biaxially oriented heat shrinkable films presently used for
- EVA-based modified anhydride adhesive having melt index of about 0.25 g/10 min (Quantum's PPX 5075) in second and third adhesive layer blends with only VLDPE as the other blend component (sample 39), or in a three component blend with EVA (as a separate constituent) and VLDPE
- samples 37, 38 and 39 were each about 2.6 mils thick and each included an oxygen barrier core layer comprising 80% EVAL H103 type EVOH and 20% nylon 1539 type 6, 66.
- the fourth outer layer of these samples comprised 75% DEFD 1192 type VLDPE and 25% DQDA 6833 type EVA.
- the fifth outer layer of these samples comprised 70.6% DEFD 1192 type VLDPE, 25% DQDA 6833 type EVA and 4.4% processing aid.
- the adhesive layers of samples 37 and 38 included 52.5% type 61509.32 VLDPE, 30% adhesive component and 17.5% DQDA 6833 type EVA.
- the sample 37 adhesive was the aforedescribed
- Plexar 3779 with 0.8 MI see Table E
- the sample 38 adhesive was Quantum's EVA-based Plexar type PPX 5075 (0.25MI).
- the sample 39 adhesive layers comprised a two component blend of 75% type 61509.32 VLDPE and 25% of the aforedescribed Quantum type PPX 5075 adhesive.
- the core layer of these samples comprised about 3% of the film thickness, and the second and third adhesive layers each also comprised about 3% of the film thickness.
- the fourth (inner) layer comprised about 63% and the fifth (outer) layer comprised 28% about of the film thickness.
- Table M The physical characteristics of these films are summarized in Table M and their physical properties are summarized in Table N.
- Sample 38 demonstrates that five layer films of this invention include adhesive layers wherein the adhesive is an EVA-based modified anhydride type with very low melt index, i.e. below about 0.5 g/10 min.
- samples 38 and 39 third adhesive layers may comprise either a two component blend of VLDPE and adhesive or a three component blend of VLDPE, EVA and adhesive with the EVA comprising up to about 25% of the total adhesive layer weight and having a fractional melt index.
- the EVA content of the three component blend should not exceed about 40% because as previously explained, higher EVA contents do not provide the
- Tables M and N indicate that the EVA-based adhesive samples 38 and 39 were equivalent to LLDPE-based adhesive sample 37 in terms of physical strength, shrinkage and oxygen permeability, and their optical properties were considered good.
- the optical performance of these 0.25 melt index based adhesive samples are substantially superior to that of substantially higher melt index type EVA-based adhesive films such as samples 25 and 26 (EVA adhesive with MI of 1.2) and sample 27 (EVA terpolymer based adhesive with MI of 0.9) Each of these films had lines.
- EVA as an adhesive base is weaker than the polyethylene and has a lower melting point, so a lower melt index EVA-based adhesive (less than about 0.5) is required to provide the same strength as a support for the stretching forces in the film than with a polyethylene-based
- a preferred EVA-based adhesive has a melt index of about 0.25 g/10 min and a vinyl acetate content of about 10 wt.%.
Abstract
Description
Claims
Priority Applications (8)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
RU95105791A RU2134276C1 (en) | 1993-04-09 | 1994-04-08 | Extended biaxially oriented thermally shrinkable multilayer film |
BR9405337-5A BR9405337A (en) | 1993-04-09 | 1994-04-08 | Extended collamed film that serves as a barrier to the passage of oxygen evoh and its process of obtaining |
EP94913409A EP0644828B1 (en) | 1993-04-09 | 1994-04-08 | Evoh oxygen barrier stretched multilayer film |
DK94913409T DK0644828T3 (en) | 1993-04-09 | 1994-04-08 | Stretched multilayer EVOH oxygen barrier film |
DE69421987T DE69421987T2 (en) | 1993-04-09 | 1994-04-08 | STRETCHED MULTI-LAYER FILM WITH OXYGEN BARRIER OF EVOH |
AU65584/94A AU672108C (en) | 1993-04-09 | 1994-04-08 | EVOH oxygen barrier stretched multilayer film |
JP6523412A JP3032296B2 (en) | 1993-04-09 | 1994-04-08 | EVOH oxygen barrier stretched multilayer film |
FI945769A FI107898B (en) | 1993-04-09 | 1994-12-08 | Stretched multilayer film with EVOH oxygen barrier |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/044,669 US5382470A (en) | 1993-04-09 | 1993-04-09 | EVOH oxygen barrier stretched multilayer film |
US08/044,669 | 1993-04-09 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1994023945A1 true WO1994023945A1 (en) | 1994-10-27 |
Family
ID=21933655
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1994/004051 WO1994023945A1 (en) | 1993-04-09 | 1994-04-08 | Evoh oxygen barrier stretched multilayer film |
Country Status (17)
Country | Link |
---|---|
US (2) | US5382470A (en) |
EP (1) | EP0644828B1 (en) |
JP (1) | JP3032296B2 (en) |
AT (1) | ATE187389T1 (en) |
AU (1) | AU672108C (en) |
BR (1) | BR9405337A (en) |
CA (1) | CA2120836C (en) |
CZ (1) | CZ288954B6 (en) |
DE (1) | DE69421987T2 (en) |
DK (1) | DK0644828T3 (en) |
ES (1) | ES2139072T3 (en) |
FI (1) | FI107898B (en) |
HU (1) | HU213628B (en) |
IL (1) | IL109270A (en) |
NZ (1) | NZ265206A (en) |
RU (1) | RU2134276C1 (en) |
WO (1) | WO1994023945A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1996018501A1 (en) * | 1994-12-16 | 1996-06-20 | W.R. Grace & Co.-Conn. | Multi-laser heat-shrinkable film |
EP0963288A1 (en) | 1997-02-28 | 1999-12-15 | Viskase Corporation | Thermoplastic c 2-alpha-olefin copolymer blends and films |
DE102006056778A1 (en) * | 2006-12-01 | 2008-06-05 | Huhtamaki Ronsberg, Zweigniederlassung Der Huhtamaki Deutschland Gmbh & Co. Kg | Method for producing a multilayer laminate |
Families Citing this family (102)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1994023946A1 (en) * | 1993-04-09 | 1994-10-27 | Viskase Corporation | A cheese package, film, bag and process for packaging a co2 respiring foodstuff |
US5834077A (en) * | 1994-10-04 | 1998-11-10 | W. R. Grace & Co.-Conn. | High shrink multilayer film which maintains optics upon shrinking |
US5837335A (en) * | 1994-10-04 | 1998-11-17 | Cryovac, Inc. | High shrink multilayer film which maintains optics upon shrinking |
US5747742A (en) * | 1995-10-16 | 1998-05-05 | Lucent Technologies, Inc. | Protective wrapping for spliced cable connectors |
US6068933A (en) * | 1996-02-15 | 2000-05-30 | American National Can Company | Thermoformable multilayer polymeric film |
DE69729763T2 (en) * | 1996-02-28 | 2004-12-09 | Cryovac, Inc. | Packaging film for cheese |
US6576305B2 (en) * | 1996-06-07 | 2003-06-10 | Saint-Gobain Vetrotex America, Inc. | Package having a multilayer film disposed around a layered coil of filament strands |
US5759648A (en) * | 1996-07-05 | 1998-06-02 | Viskase Corporation | Multilayer plastic film, useful for packaging a cook-in foodstuff |
US6306472B1 (en) * | 1998-04-22 | 2001-10-23 | Pechiney Emballage Flexible Europe | Eva-evoh delamination seal |
AU765233B2 (en) | 1998-12-18 | 2003-09-11 | Cryovac, Inc. | Highly bi-axially oriented, heat-shrinkable, thermoplastic, multi-layer film and process for the manufacture thereof |
US6383589B1 (en) | 1999-03-29 | 2002-05-07 | Pechiney Plastic Packaging, Inc. | Multilayer plastic structures, containers made therefrom, and methods of making the structures |
US6291041B1 (en) | 1999-05-10 | 2001-09-18 | Curwood, Inc. | Heat resistant nylon multi-layer film |
US6861127B2 (en) | 1999-10-20 | 2005-03-01 | Curwood, Inc. | Thermoformable multi-layer film |
US6869686B1 (en) | 2000-08-30 | 2005-03-22 | Curwood, Inc. | Irradiated biaxially oriented film |
US7537829B2 (en) * | 2001-02-22 | 2009-05-26 | Exxonmobil Oil Corporation | Multi-layer films having improved sealing properties |
US6893672B2 (en) * | 2001-09-07 | 2005-05-17 | Pechiney Emballage Flexible Europe | Peelable film and packaging made therefrom |
US6893722B2 (en) * | 2002-04-29 | 2005-05-17 | Exxonmobil Oil Corporation | Cationic, amino-functional, adhesion-promoting polymer for curable inks and other plastic film coatings, and plastic film comprising such polymer |
US7195818B2 (en) | 2002-05-01 | 2007-03-27 | Exxonmobil Oil Corporation | Sealable multi-layer opaque film |
US7029734B1 (en) * | 2002-08-20 | 2006-04-18 | Curwood, Inc. | Packaging film, package and process for aseptic packaging |
US6893730B2 (en) * | 2002-09-24 | 2005-05-17 | Honeywell International Inc. | Barrier film with reduced dynamic coefficient of friction |
US20040105994A1 (en) | 2002-12-03 | 2004-06-03 | Pang-Chia Lu | Thermoplastic film structures with a low melting point outer layer |
US6908687B2 (en) | 2002-12-30 | 2005-06-21 | Exxonmobil Oil Corporation | Heat-shrinkable polymeric films |
US20040175464A1 (en) * | 2003-03-07 | 2004-09-09 | Blemberg Robert J. | Multilayer structures, packages, and methods of making multilayer structures |
US20040175466A1 (en) | 2003-03-07 | 2004-09-09 | Douglas Michael J. | Multilayer barrier structures, methods of making the same and packages made therefrom |
US7008677B2 (en) * | 2003-09-23 | 2006-03-07 | Pechiney Emballage Flexible Europe | Film structures and packages therefrom useful for packaging respiring food products |
US7276269B2 (en) * | 2003-12-10 | 2007-10-02 | Curwood, Inc. | Frangible heat-sealable films for cook-in applications and packages made thereof |
US7147930B2 (en) * | 2003-12-16 | 2006-12-12 | Curwood, Inc. | Heat-shrinkable packaging films with improved sealing properties and articles made thereof |
ES2283709T3 (en) * | 2003-12-19 | 2007-11-01 | KRAFT FOODS R & D, INC. ZWEIGNIEDERLASSUNG MUNCHEN | WAXED CHEESE. |
US8545950B2 (en) * | 2004-04-02 | 2013-10-01 | Curwood, Inc. | Method for distributing a myoglobin-containing food product |
US7867531B2 (en) | 2005-04-04 | 2011-01-11 | Curwood, Inc. | Myoglobin blooming agent containing shrink films, packages and methods for packaging |
US8470417B2 (en) | 2004-04-02 | 2013-06-25 | Curwood, Inc. | Packaging inserts with myoglobin blooming agents, packages and methods for packaging |
US8029893B2 (en) | 2004-04-02 | 2011-10-04 | Curwood, Inc. | Myoglobin blooming agent, films, packages and methods for packaging |
US8053047B2 (en) | 2004-04-02 | 2011-11-08 | Curwood, Inc. | Packaging method that causes and maintains the preferred red color of fresh meat |
US8741402B2 (en) * | 2004-04-02 | 2014-06-03 | Curwood, Inc. | Webs with synergists that promote or preserve the desirable color of meat |
US8110259B2 (en) | 2004-04-02 | 2012-02-07 | Curwood, Inc. | Packaging articles, films and methods that promote or preserve the desirable color of meat |
EP1750941A1 (en) * | 2004-05-07 | 2007-02-14 | A.W.A.X. PROGETTAZIONE E RICERCA S.r.l. | Extensible multilayer film |
US20060062947A1 (en) * | 2004-09-21 | 2006-03-23 | Scott Huffer | Packaging material with energy cured, hotmelt-receptive coating and package made therefrom |
DE102005003922A1 (en) * | 2005-01-27 | 2006-08-03 | Ccl Label Gmbh | Sealable tubular polymer foil laminate has at least a sealable outer print foil of a high density polyethylene material and an inner polymer support foil with similar melting point to seal with print foil |
US20060228503A1 (en) * | 2005-04-12 | 2006-10-12 | Marvin Havens | Film for chub packaging |
EP1746046A1 (en) * | 2005-07-19 | 2007-01-24 | Cryovac, Inc. | Vacuum skin package for cheese |
US20070031546A1 (en) * | 2005-08-05 | 2007-02-08 | Curwood, Inc. | Polyester and polyamide blend containing article for packaging a CO2 respiring foodstuff |
US20070092744A1 (en) * | 2005-10-13 | 2007-04-26 | Plasticos Dise S.A. | Polymer compositions and films and method of making |
US20070172614A1 (en) * | 2005-12-30 | 2007-07-26 | I-Hwa Lee | Heat shrinkable multilayer film and tube with improved adhesion after orientation |
US8202001B1 (en) * | 2006-01-26 | 2012-06-19 | Chunhua Zhang | Self-opening bag pack and method thereof |
EP1857270B1 (en) | 2006-05-17 | 2013-04-17 | Curwood, Inc. | Myoglobin blooming agent, films, packages and methods for packaging |
US20080017655A1 (en) * | 2006-07-19 | 2008-01-24 | Martel Shelly A | Food container assembly |
DE102006040526A1 (en) * | 2006-08-30 | 2008-03-06 | Cfs Kempten Gmbh | Thermoformable packaging material with shrink properties |
WO2009057181A1 (en) * | 2007-10-29 | 2009-05-07 | Shikoku Kakoh Co., Ltd. | Film for food packaging |
AU2007338949A1 (en) * | 2006-12-22 | 2008-07-03 | The New Zealand Institute Of Plant And Food Research Limited | Sensor device |
FR2912682B1 (en) * | 2007-02-21 | 2013-07-26 | Bollore | 5 - LAYER BARRIER FILM, SEALING METHOD, APPLICATION TO PACKAGING FOOD PRODUCT. |
US7946766B2 (en) | 2007-06-15 | 2011-05-24 | S.C. Johnson & Son, Inc. | Offset closure mechanism for a reclosable pouch |
US7967509B2 (en) * | 2007-06-15 | 2011-06-28 | S.C. Johnson & Son, Inc. | Pouch with a valve |
US7874731B2 (en) * | 2007-06-15 | 2011-01-25 | S.C. Johnson Home Storage, Inc. | Valve for a recloseable container |
US7857515B2 (en) * | 2007-06-15 | 2010-12-28 | S.C. Johnson Home Storage, Inc. | Airtight closure mechanism for a reclosable pouch |
US7887238B2 (en) * | 2007-06-15 | 2011-02-15 | S.C. Johnson Home Storage, Inc. | Flow channels for a pouch |
US8815360B2 (en) * | 2007-08-28 | 2014-08-26 | Cryovac, Inc. | Multilayer film having passive and active oxygen barrier layers |
EP2236285B2 (en) * | 2007-12-17 | 2019-05-08 | Kureha Corporation | Thermally shrinkable laminate film for deep drawing, packaged article, and method for packaging of cheese |
US8127519B2 (en) * | 2008-07-14 | 2012-03-06 | Stravitz David M | Method of inserting and storing waste for disposal |
US8215089B2 (en) | 2008-07-14 | 2012-07-10 | David Stravitz | Waste disposal devices |
US20100015423A1 (en) * | 2008-07-18 | 2010-01-21 | Schaefer Suzanne E | Polyamide structures for the packaging of moisture containing products |
CA2732669C (en) * | 2008-08-07 | 2016-02-09 | Invista Technologies S.A.R.L. | Airbag fabrics woven from slit-film polymeric tapes |
US7981492B2 (en) * | 2008-10-28 | 2011-07-19 | Exopack, Llc | Film structures and packages therefrom useful for respiring food products that release CO2 amounts |
USD639002S1 (en) | 2009-10-30 | 2011-05-31 | Munchkin, Inc. | Diaper pail bag |
USD619905S1 (en) | 2009-10-30 | 2010-07-20 | Munchkin, Inc. | Diaper pail bag |
US8690017B2 (en) | 2009-10-30 | 2014-04-08 | Munchkin, Inc. | Powder dispensing assembly for a waste container |
US8647587B2 (en) | 2009-10-30 | 2014-02-11 | Munchkin, Inc | Powder dispensing assembly for a waste container |
US8567157B2 (en) | 2009-10-30 | 2013-10-29 | Munchkin, Inc. | System for disposing waste packages such as diapers |
US8635838B2 (en) | 2009-10-30 | 2014-01-28 | Munchkin, Inc. | System for disposing waste packages such as diapers |
US8833592B2 (en) | 2009-10-30 | 2014-09-16 | Munchkin, Inc. | System and method for disposing waste packages such as diapers |
USD639003S1 (en) | 2009-10-30 | 2011-05-31 | Munchkin, Inc. | Diaper pail bag |
USD639004S1 (en) | 2009-10-30 | 2011-05-31 | Munchkin, Inc. | Diaper pail bag |
US10343842B2 (en) | 2009-10-30 | 2019-07-09 | Munchkin, Inc. | System and method for disposing waste packages such as diapers |
US8739501B2 (en) | 2009-10-30 | 2014-06-03 | Munchkin, Inc. | System for disposing waste packages such as diapers |
US8574694B2 (en) | 2009-11-03 | 2013-11-05 | Curwood, Inc. | Packaging sheet with improved cutting properties |
US20110104342A1 (en) * | 2009-11-03 | 2011-05-05 | Kevin David Glaser | Chlorine-Free Packaging Sheet with Tear-Resistance Properties |
US20110189356A1 (en) * | 2010-01-29 | 2011-08-04 | Shy Brothers Farm | Methods of Storing Cheese |
ES2812538T3 (en) * | 2010-11-11 | 2021-03-17 | Danapak Flexibles As | A laminate for use in packaging, a method of making and use of a reclosable laminate |
DE202011110798U1 (en) | 2011-05-03 | 2016-08-09 | Flexopack S.A. | Waste packaging system and foil |
US9604430B2 (en) | 2012-02-08 | 2017-03-28 | Flexopack S.A. | Thin film for waste packing cassettes |
FR2987380B1 (en) * | 2012-02-28 | 2014-02-07 | Saint Gobain Isover | PA666 / EVOH MIXER-BASED VAPOR MEMBRANE |
WO2013134335A2 (en) * | 2012-03-06 | 2013-09-12 | Dupont Teijin Films U.S. Limited Partnership | Heat sealable nylon film and method of making it |
WO2013174792A1 (en) * | 2012-05-21 | 2013-11-28 | Dupont Nutrition Biosciences Aps | Strains of lactobacillus with antifungal properties |
BR112015004046A2 (en) * | 2012-08-31 | 2017-07-04 | Dow Global Technologies Llc | multilayer film and article |
US9624019B2 (en) * | 2012-11-09 | 2017-04-18 | Winpak Films Inc. | High oxygen and water barrier multilayer film |
US20140370211A1 (en) * | 2013-06-14 | 2014-12-18 | Prolamina Midwest Corporation | Carbon dioxide gas permeable packaging film |
EP2813362B1 (en) * | 2013-06-14 | 2019-05-22 | Flexopack S.A. | Heat shrinkable film |
WO2015181333A1 (en) * | 2014-05-28 | 2015-12-03 | Cryovac, Inc. | Multilayer heat shrinkable films |
EP2963177A1 (en) * | 2014-07-04 | 2016-01-06 | Danapak Flexibles A/S | A packaging sheet for packaging cheese, and associated packaging and manufacturing methods |
AU2015258191B2 (en) | 2014-11-19 | 2020-02-27 | Flexopack S.A. | Oven skin packaging process |
US9994393B2 (en) | 2014-12-11 | 2018-06-12 | Munchkin, Inc. | Container for receiving multiple flexible bag assemblies |
JP2019517938A (en) | 2016-06-03 | 2019-06-27 | ボレアリス エージー | Multilayer structure |
US10633524B2 (en) | 2016-12-01 | 2020-04-28 | Cryovac, Llc | Multilayer heat shrinkable films |
AU2018253212B2 (en) | 2017-04-13 | 2023-02-23 | Cryovac, Llc | High-shrink, high-strength multilayer film containing three-component blend |
EP3476593A1 (en) | 2017-10-24 | 2019-05-01 | Renolit SE | Laminate structure for barrier packaging |
EP3501822A1 (en) | 2017-12-22 | 2019-06-26 | Flexopack S.A. | Fibc liner film |
EP3808682A4 (en) * | 2018-06-12 | 2022-03-23 | Toyobo Co., Ltd. | Freshness-retaining polyester film and package |
EP3877175A4 (en) | 2018-11-09 | 2022-08-10 | Sofresh, Inc. | Blown film materials and processes for manufacturing thereof and uses thereof |
CN115243862A (en) * | 2020-02-07 | 2022-10-25 | 贝里国际公司 | Laminated container |
CA3178692A1 (en) * | 2020-04-07 | 2021-10-14 | Sofresh, Inc. | Laminated film materials and processes for manufacturing thereof and uses thereof |
US10975181B1 (en) | 2020-12-30 | 2021-04-13 | Chang Chun Petrochemical Co., Ltd. | Ethylene-vinyl alcohol copolymer and producing method thereof |
CN113480799B (en) * | 2021-08-25 | 2023-09-29 | 合诚技术股份有限公司 | Medical EVA catheter material with surface frosting effect, and preparation method and application thereof |
GB2617889A (en) * | 2022-02-15 | 2023-10-25 | Flexopack Sa | Heat shrinkable film |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0141555A1 (en) * | 1983-10-14 | 1985-05-15 | American Can Company | Oriented polymeric films, packaging made from such films and methods of making the films and packaging |
EP0236099A2 (en) * | 1986-02-28 | 1987-09-09 | W.R. Grace & Co.-Conn. | Oxygen barrier packaging film |
EP0323852A2 (en) * | 1988-01-06 | 1989-07-12 | Viskase Corporation | Multilayer thermoplastic film |
US4857399A (en) * | 1986-12-29 | 1989-08-15 | Viskase Corporation | Shrink film |
EP0409615A2 (en) * | 1989-07-20 | 1991-01-23 | E.I. Du Pont De Nemours And Company | Tough monolayer shrink film for products containing moisture |
US5004647A (en) * | 1986-03-21 | 1991-04-02 | W. R. Grace & Co.-Conn. | Oxygen barrier biaxially oriented film |
EP0457598A2 (en) * | 1990-05-17 | 1991-11-21 | W.R. Grace & Co.-Conn. | Breathable abuse resistant film for packaging cheese |
EP0562493A1 (en) * | 1992-03-23 | 1993-09-29 | Viskase Corporation | Biaxially oriented heat shrinkable film |
Family Cites Families (63)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA743021A (en) | 1966-09-20 | W.R. Grace And Co. | Vinylidene chloride polymeric film and a process for the production thereof | |
US1925443A (en) | 1932-01-27 | 1933-09-05 | Natural Cheese Corp | Packaging cheese |
US2494636A (en) | 1946-06-15 | 1950-01-17 | Kraft Foods Co | Emmenthaler cheese |
US2813028A (en) | 1952-05-16 | 1957-11-12 | Armour & Co | Processing of cheddar cheese |
US2871126A (en) | 1955-01-19 | 1959-01-27 | Nat Dairy Prod Corp | Manufacture of cheese |
US3456044A (en) | 1965-03-12 | 1969-07-15 | Heinz Erich Pahlke | Biaxial orientation |
US3585177A (en) | 1966-11-30 | 1971-06-15 | Monsanto Co | Novel poly(olefin/vinyl alcohol) packaging materials |
US3741253A (en) | 1971-03-30 | 1973-06-26 | Grace W R & Co | Laminates of ethylene vinyl acetate polymers and polymers of vinylidene chloride |
GB1384791A (en) | 1972-04-28 | 1975-02-19 | Grace W R & Co | Laminates |
AR207667A1 (en) | 1974-12-23 | 1976-10-22 | Grace W R & Co | PROCEDURE TO OBTAIN ORIENTED POLYAMIDE LAMINATES AND THE LAMINATE SO OBTAINED |
US4058647A (en) | 1975-02-27 | 1977-11-15 | Mitsubishi Petrochemical Co., Ltd. | Process for preparing laminated resin product |
US3997383A (en) | 1975-03-10 | 1976-12-14 | W. R. Grace & Co. | Cross-linked amide/olefin polymeric laminates |
US4087587A (en) | 1975-09-19 | 1978-05-02 | Chemplex Company | Adhesive blends |
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 |
US4233367A (en) | 1977-01-06 | 1980-11-11 | American Can Company | Coextruded multilayer film |
US4178401A (en) | 1978-01-09 | 1979-12-11 | W. R. Grace & Co. | Packaging film comprising a blended self-welding layer |
US4254169A (en) | 1978-12-28 | 1981-03-03 | American Can Company | Multi-layer barrier film |
US4284674A (en) | 1979-11-08 | 1981-08-18 | American Can Company | Thermal insulation |
US4816342A (en) | 1979-12-10 | 1989-03-28 | American National Can Company | Polymeric structure having improved barrier properties and method of making same |
US4407897A (en) * | 1979-12-10 | 1983-10-04 | American Can Company | Drying agent in multi-layer polymeric structure |
US4770944A (en) | 1979-12-10 | 1988-09-13 | American Can Company | Polymeric structure having improved barrier properties and method of making same |
JPS56157355A (en) | 1980-05-08 | 1981-12-04 | Tokan Kogyo Co Ltd | Laminated film using regenerated resin and its manufacture and its device |
US4552801A (en) | 1981-04-01 | 1985-11-12 | American Can Company | Plasticized EVOH and process and products utilizing same |
US4352844A (en) | 1981-05-29 | 1982-10-05 | W. R. Grace & Co. | Thermoplastic film having improved handling and sealing characteristics and receptacle formed therefrom |
US4610914A (en) | 1981-08-05 | 1986-09-09 | American Can Company | Oriented films of blends of EVOH copolymer |
US4828915A (en) | 1981-08-05 | 1989-05-09 | American National Can Company | Oriented evoh/nylon blend film |
JPS5882752A (en) | 1981-11-11 | 1983-05-18 | 呉羽化学工業株式会社 | Heat-shrinkable film |
JPS58142848A (en) * | 1982-02-19 | 1983-08-25 | 呉羽化学工業株式会社 | Laminated film |
ATE51639T1 (en) | 1982-04-26 | 1990-04-15 | American National Can Co | POLYMER MATERIAL COMPOSITION, ORIENTED POLYMER FILMS AND SHRINKABLE BAGS MADE THEREOF. |
US4457960A (en) | 1982-04-26 | 1984-07-03 | American Can Company | Polymeric and film structure for use in shrink bags |
US4448792A (en) | 1982-07-26 | 1984-05-15 | W. R. Grace & Co., Cryovac Division | Pasteurizable and cook-in shrink bag constructed of a multilayer film |
IL71357A (en) | 1983-03-29 | 1987-03-31 | Union Carbide Corp | Process for producing low density ethylene copolymers |
US4501798A (en) | 1983-05-05 | 1985-02-26 | American Can Company | Unbalanced oriented multiple layer film |
US4615922A (en) * | 1983-10-14 | 1986-10-07 | American Can Company | Oriented polymeric film |
US4561920A (en) | 1984-02-08 | 1985-12-31 | Norchem, Inc. Formerly Northern Petrochemical Company | Biaxially oriented oxygen and moisture barrier film |
US4683170A (en) | 1984-06-29 | 1987-07-28 | American Can Company | Nylon copolymer and nylon blends and films made therefrom |
US4647483A (en) | 1984-06-29 | 1987-03-03 | American Can Company | Nylon copolymer and nylon blends and films made therefrom |
US4615926A (en) * | 1984-07-20 | 1986-10-07 | American Can Company | Film and package having strong seals and a modified ply-separation opening |
DE3576931D1 (en) | 1984-11-12 | 1990-05-10 | Kuraray Co | MULTILAYER MATERIALS AND METHOD FOR THE PRODUCTION THEREOF. |
US4737391A (en) | 1984-12-03 | 1988-04-12 | Viskase Corporation | Irradiated multilayer film for primal meat packaging |
US4640856A (en) | 1985-04-29 | 1987-02-03 | W. R. Grace & Co., Cryovac Div. | Multi-layer packaging film and receptacles made therefrom |
CA1340037C (en) | 1985-06-17 | 1998-09-08 | Stanley Lustig | Puncture resistant, heat-shrinkable films containing very low density polyethylene copolymer |
US4726984A (en) | 1985-06-28 | 1988-02-23 | W. R. Grace & Co. | Oxygen barrier oriented film |
US4724185A (en) * | 1985-09-17 | 1988-02-09 | W. R. Grace & Co., Cryovac Div. | Oxygen barrier oriented film |
US4755419A (en) | 1986-03-21 | 1988-07-05 | W. R. Grace & Co., Cryovac Div. | Oxygen barrier oriented shrink film |
US4753700A (en) | 1986-02-28 | 1988-06-28 | W. R. Grace & Co., Cryovac Div. | Packaging film |
DE3681790D1 (en) | 1986-04-15 | 1991-11-07 | Grace W R & Co | MULTILAYER PACKAGING FILM. |
US4839235A (en) | 1986-06-30 | 1989-06-13 | W. R. Grace & Co. | Oxygen barrier film |
US4758463A (en) * | 1986-12-29 | 1988-07-19 | Viskase Corporation | Cook-in shrink film |
US4734327A (en) * | 1986-12-29 | 1988-03-29 | Viskase Corporation | Cook-in shrink film |
US4857408A (en) * | 1986-12-29 | 1989-08-15 | Viskase Corporation | Meat adherable cook-in shrink film |
US4952628A (en) | 1987-08-24 | 1990-08-28 | E. I. Du Pont De Nemours And Company | Barrier blends based on amorphous polyamide and ethylene/vinyl alcohol, unaffected by humidity |
US5165988A (en) | 1987-12-14 | 1992-11-24 | American National Can Company | Laminates and laminated tubes and packages |
CA1335424C (en) | 1987-12-29 | 1995-05-02 | Tohei Moritani | Multilayered packaging materials having high gas barrier property |
US4939076A (en) | 1988-03-15 | 1990-07-03 | W. R. Grace & Co.-Conn. | Barrier stretch film |
NZ226983A (en) | 1988-11-17 | 1990-08-28 | Grace W R Nz | Multilayer heat shrink film comprising ethylene/vinyl acetate copolymer and very low density polyethylene polymer layers |
JP2751409B2 (en) | 1989-05-31 | 1998-05-18 | 三菱化学株式会社 | Resin composition and molded article thereof |
US5075143A (en) * | 1989-09-29 | 1991-12-24 | W. R. Grace & Co.-Conn. | High barrier implosion resistant films |
GB2248621B (en) | 1990-09-07 | 1994-08-17 | Grace W R & Co | Polymer mixture |
ZA918226B (en) | 1990-11-16 | 1992-07-29 | Grace W R & Co | Cheese packaging laminate |
DE4130485A1 (en) | 1991-08-23 | 1993-02-25 | Wolff Walsrode Ag | COEXTRUDED BIAXIAL STRETCHED TUBE FILM |
DE4128081A1 (en) | 1991-08-23 | 1993-02-25 | Wolff Walsrode Ag | COEXTRUDED BIAXIAL STRETCHED TUBE FILM |
JP3104885B2 (en) | 1992-03-13 | 2000-10-30 | 大倉工業株式会社 | Heat shrinkable laminated film |
-
1993
- 1993-04-09 US US08/044,669 patent/US5382470A/en not_active Expired - Lifetime
-
1994
- 1994-02-03 US US08/191,886 patent/US6316067B1/en not_active Expired - Fee Related
- 1994-04-08 AT AT94913409T patent/ATE187389T1/en active
- 1994-04-08 DK DK94913409T patent/DK0644828T3/en active
- 1994-04-08 CZ CZ19943098A patent/CZ288954B6/en not_active IP Right Cessation
- 1994-04-08 JP JP6523412A patent/JP3032296B2/en not_active Expired - Fee Related
- 1994-04-08 BR BR9405337-5A patent/BR9405337A/en not_active IP Right Cessation
- 1994-04-08 DE DE69421987T patent/DE69421987T2/en not_active Expired - Lifetime
- 1994-04-08 CA CA002120836A patent/CA2120836C/en not_active Expired - Fee Related
- 1994-04-08 RU RU95105791A patent/RU2134276C1/en not_active IP Right Cessation
- 1994-04-08 HU HU9403515A patent/HU213628B/en not_active IP Right Cessation
- 1994-04-08 EP EP94913409A patent/EP0644828B1/en not_active Expired - Lifetime
- 1994-04-08 NZ NZ265206A patent/NZ265206A/en not_active IP Right Cessation
- 1994-04-08 WO PCT/US1994/004051 patent/WO1994023945A1/en active IP Right Grant
- 1994-04-08 AU AU65584/94A patent/AU672108C/en not_active Ceased
- 1994-04-08 ES ES94913409T patent/ES2139072T3/en not_active Expired - Lifetime
- 1994-04-10 IL IL10927094A patent/IL109270A/en not_active IP Right Cessation
- 1994-12-08 FI FI945769A patent/FI107898B/en not_active IP Right Cessation
Patent Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0141555A1 (en) * | 1983-10-14 | 1985-05-15 | American Can Company | Oriented polymeric films, packaging made from such films and methods of making the films and packaging |
US4557780A (en) * | 1983-10-14 | 1985-12-10 | American Can Company | Method of making an oriented polymeric film |
EP0236099A2 (en) * | 1986-02-28 | 1987-09-09 | W.R. Grace & Co.-Conn. | Oxygen barrier packaging film |
US5004647A (en) * | 1986-03-21 | 1991-04-02 | W. R. Grace & Co.-Conn. | Oxygen barrier biaxially oriented film |
US4857399A (en) * | 1986-12-29 | 1989-08-15 | Viskase Corporation | Shrink film |
EP0323852A2 (en) * | 1988-01-06 | 1989-07-12 | Viskase Corporation | Multilayer thermoplastic film |
US4851290A (en) * | 1988-01-06 | 1989-07-25 | Viskase Corporation | Multilayer thermoplastic film |
EP0334293A2 (en) * | 1988-03-25 | 1989-09-27 | Viskase Corporation | Shrink film |
EP0409615A2 (en) * | 1989-07-20 | 1991-01-23 | E.I. Du Pont De Nemours And Company | Tough monolayer shrink film for products containing moisture |
EP0457598A2 (en) * | 1990-05-17 | 1991-11-21 | W.R. Grace & Co.-Conn. | Breathable abuse resistant film for packaging cheese |
EP0562493A1 (en) * | 1992-03-23 | 1993-09-29 | Viskase Corporation | Biaxially oriented heat shrinkable film |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1996018501A1 (en) * | 1994-12-16 | 1996-06-20 | W.R. Grace & Co.-Conn. | Multi-laser heat-shrinkable film |
US6150011A (en) * | 1994-12-16 | 2000-11-21 | Cryovac, Inc. | Multi-layer heat-shrinkage film with reduced shrink force, process for the manufacture thereof and packages comprising it |
EP0963288A1 (en) | 1997-02-28 | 1999-12-15 | Viskase Corporation | Thermoplastic c 2-alpha-olefin copolymer blends and films |
DE102006056778A1 (en) * | 2006-12-01 | 2008-06-05 | Huhtamaki Ronsberg, Zweigniederlassung Der Huhtamaki Deutschland Gmbh & Co. Kg | Method for producing a multilayer laminate |
Also Published As
Publication number | Publication date |
---|---|
NZ265206A (en) | 1996-09-25 |
AU672108C (en) | 2003-08-07 |
JPH08500551A (en) | 1996-01-23 |
IL109270A (en) | 1996-08-04 |
JP3032296B2 (en) | 2000-04-10 |
CZ309894A3 (en) | 1995-05-17 |
FI107898B (en) | 2001-10-31 |
US5382470A (en) | 1995-01-17 |
HU9403515D0 (en) | 1995-02-28 |
AU672108B2 (en) | 1996-09-19 |
ES2139072T3 (en) | 2000-02-01 |
RU95105791A (en) | 1996-10-27 |
DE69421987D1 (en) | 2000-01-13 |
FI945769A (en) | 1995-02-07 |
AU6558494A (en) | 1994-11-08 |
DE69421987T2 (en) | 2000-06-15 |
CA2120836C (en) | 2000-06-13 |
CZ288954B6 (en) | 2001-10-17 |
EP0644828B1 (en) | 1999-12-08 |
FI945769A0 (en) | 1994-12-08 |
HUT71506A (en) | 1995-12-28 |
RU2134276C1 (en) | 1999-08-10 |
CA2120836A1 (en) | 1994-10-10 |
US6316067B1 (en) | 2001-11-13 |
ATE187389T1 (en) | 1999-12-15 |
IL109270A0 (en) | 1994-07-31 |
DK0644828T3 (en) | 2000-04-17 |
HU213628B (en) | 1997-08-28 |
EP0644828A1 (en) | 1995-03-29 |
BR9405337A (en) | 1999-08-31 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
AU672108C (en) | EVOH oxygen barrier stretched multilayer film | |
US6063462A (en) | Multilayer film | |
EP0217596B1 (en) | Oxygen barrier oriented film | |
US4734327A (en) | Cook-in shrink film | |
US4857399A (en) | Shrink film | |
US5004647A (en) | Oxygen barrier biaxially oriented film | |
AU617119B2 (en) | Thermoplastic packaging film of low i10/i2 | |
US4758463A (en) | Cook-in shrink film | |
AU765377B2 (en) | New high resistance heat-shrinkable thermoplastic film | |
JPH1029283A (en) | Heat-sealable film | |
EP0744285A1 (en) | Multilayer oxygen barrier packaging film | |
US4857408A (en) | Meat adherable cook-in shrink film | |
AU698490B2 (en) | Mutilayer heat-shrinkable films with improved mechanical properties | |
AU758775B2 (en) | Breathable film for cheese packaging | |
EP0251769B1 (en) | Oxygen barrier film | |
AU597627B2 (en) | Oxygen barrier oriented film | |
AU736684B2 (en) | Multilayer film | |
AU8731301A (en) | Multilayer film |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AU BR CZ FI HU JP NZ RU |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE |
|
WWE | Wipo information: entry into national phase |
Ref document number: 265206 Country of ref document: NZ |
|
WWE | Wipo information: entry into national phase |
Ref document number: PV1994-3098 Country of ref document: CZ Ref document number: 945769 Country of ref document: FI |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1994913409 Country of ref document: EP |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWP | Wipo information: published in national office |
Ref document number: 1994913409 Country of ref document: EP |
|
WWP | Wipo information: published in national office |
Ref document number: PV1994-3098 Country of ref document: CZ |
|
WWG | Wipo information: grant in national office |
Ref document number: 1994913409 Country of ref document: EP |
|
WWG | Wipo information: grant in national office |
Ref document number: PV1994-3098 Country of ref document: CZ |
|
WWG | Wipo information: grant in national office |
Ref document number: 945769 Country of ref document: FI |