WO2001012436A2 - Multilayer barrier structures and process for preparing the same - Google Patents

Multilayer barrier structures and process for preparing the same Download PDF

Info

Publication number
WO2001012436A2
WO2001012436A2 PCT/US2000/020205 US0020205W WO0112436A2 WO 2001012436 A2 WO2001012436 A2 WO 2001012436A2 US 0020205 W US0020205 W US 0020205W WO 0112436 A2 WO0112436 A2 WO 0112436A2
Authority
WO
WIPO (PCT)
Prior art keywords
weight percent
layer
melt index
content
vinyl acetate
Prior art date
Application number
PCT/US2000/020205
Other languages
French (fr)
Other versions
WO2001012436A3 (en
Inventor
Carlos E. Hinton
John A. Naumovitz
Original Assignee
The Dow Chemical Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by The Dow Chemical Company filed Critical The Dow Chemical Company
Priority to AU63726/00A priority Critical patent/AU6372600A/en
Publication of WO2001012436A2 publication Critical patent/WO2001012436A2/en
Publication of WO2001012436A3 publication Critical patent/WO2001012436A3/en

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
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B32B27/304—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF
    • 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
    • B32B27/34—Layered products comprising a layer of synthetic resin comprising polyamides
    • 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
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/12—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by using adhesives
    • 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
    • B32B2307/70—Other properties
    • B32B2307/724—Permeability to gases, adsorption
    • B32B2307/7242—Non-permeable
    • 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
    • B32B2323/00—Polyalkenes
    • B32B2323/04—Polyethylene
    • B32B2323/043—HDPE, i.e. high density polyethylene
    • 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
    • B32B2327/00—Polyvinylhalogenides
    • B32B2327/06—PVC, i.e. polyvinylchloride
    • 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
    • B32B2377/00—Polyamides
    • 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
    • B32B2439/00—Containers; Receptacles
    • 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
    • B32B2553/00—Packaging equipment or accessories not otherwise provided for

Definitions

  • This invention relates to a multilayer structure, and more particularly to a multilayer structure comprising a layer of a vinylidene chloride polymer.
  • a vinylidene chloride polymer film or sheet provides high gas and water barrier properties in packaging materials or other containers, it does not provide such desirable mechanical properties as good abrasion resistance, high tensile strength and high impact strength.
  • One approach in solving this problem is to provide a multilayer structure wherein one layer comprises a vinylidene chloride polymer and another layer comprises a polymer which provides the requisite good mechanical properties in the multilayer structure.
  • many types of thermoplastic polymers possess excellent mechanical properties, they do not readily bond to other types of polymers.
  • high density polyethylene, polypropylene and nylon are typical resins used for toughness, but they are incompatible with vinylidene chloride polymer resins and, therefore, film layers made from these resins do not readily bond to the vinylidene chloride polymer layer.
  • incompatible polymer layers can be joined together by using a tie layer or adhesive layer between the two layers.
  • a tie layer can be compatible with one of the two incompatible layers but not with the other layer.
  • the present invention is a three-layer barrier structure comprising a first layer comprising a vinylidene chloride polymer (PVDC), a second layer comprising a dissimilar high melting point polymer (HMPP) and a tie layer disposed between the first and second layers, the tie layer comprising an adhesive which bonds well to both the first layer and the second layer and effectively ties the two layers together.
  • PVDC vinylidene chloride polymer
  • HMPP dissimilar high melting point polymer
  • the present invention is a multilayer structure comprising the three-layer structure of the first aspect and other polymer layers added to the three-layer structure.
  • Such other polymers include polyolefins, polyamides, polymers based on aromatic monomers, and chlorinated polyolefins.
  • the present invention is a process for preparing the multilayer structure of the first aspect comprising providing a first layer comprising a vinylidene chloride polymer (PVDC), adhering to the first layer a second layer comprising a dissimilar high melting point polymer (HMPP) by using a tie layer comprising an adhesive which bonds well to both the first layer and the second layer and effectively ties the two layers together.
  • PVDC vinylidene chloride polymer
  • HMPP dissimilar high melting point polymer
  • the present invention is a process for preparing the multilayer structure of the first aspect comprising coextruding a first layer comprising a vinylidene chloride polymer (PVDC), a second layer comprising a dissimilar high melting point polymer (HMPP) and a tie layer disposed between the first and second layers, the tie layer comprising an adhesive which bonds well to both the first layer and the second layer and effectively ties the two layers together.
  • PVDC vinylidene chloride polymer
  • HMPP dissimilar high melting point polymer
  • the multilayer structures of the present invention are particularly suited for fabrication into flexible and rigid containers used for the preservation of food, drink, medicine and other perishables.
  • Such containers should have good mechanical properties, as well as low gas permeabilities too, for example, oxygen, carbon dioxide, water vapor, odor bodies or flavor bodies, hydrocarbons or agricultural chemicals.
  • Adhesives which can be employed in the practice of the present invention for preparing the multilayer structures include, in general, ethylene vinyl acetate copolymers, ethylene/ethyl acrylic acid ester copolymers, ionomers, modified polyolefins as described in U.S. Patent 5,443,874, acrylic-based terpolymer adhesives as described in U.S. Patent 3,753,769 and adhesives formed by reacting an epoxy resin and an acidified aminoethylated vinyl polymer as described in U.S. Patent 4,447,494.
  • the adhesives which can be employed in the practice of the present invention to effectively tie the two layers together include (1) an ethylene vinyl acetate copolymer (EVA) having a vinyl acetate content of from 9 to 28 weight percent and a melt index of from 2 to 8; (2) an ethylene acrylic ester copolymer having an acrylic ester content of from 23 to 30 weight percent and a melt index of from 6 to 8; (3) an ethylene methyl acrylate having a methyl acrylate content of 24 weight percent and a melt index of 10; (4) an anhydride- modified ethylene vinyl acetate copolymer having a melt index of from 4.5 to 5; (5) a blend of from 60 to 70 weight percent ethylene vinyl acetate copolymer having a vinyl acetate content WO 01/12436 PCT/US0O/2O2O5
  • the adhesives which can be employed to effectively tie the two layers together include (1) an ethylene vinyl acetate copolymer (EVA) having a vinyl acetate content of from 9 to 28 weight percent and a melt index of from 2 to 8; (2) an ethylene acrylic ester copolymer having an acrylic ester content of from 12 to 30 weight percent and a melt index of from 6 to 8; (3) an ethylene methyl acrylate having a methyl acrylate content of 24 weight percent and a melt index of 10; (4) an anhydride-modified ethylene vinyl acetate copolymer having a melt index of from 2 to 5.7; (5) a blend of from 50 to 70 weight percent ethylene vinyl acetate copolymer having a vinyl acetate content of 28 weight percent and a melt index of from 6 to 7 and from 30 to 50 weight percent polyprop
  • EVA ethylene vinyl acetate copolymer
  • EVA ethylene acrylic ester copolymer having an acrylic ester content of from 12 to 30 weight percent and a melt index of from 6
  • the adhesives which can be employed in the practice of the present invention to effectively tie the two layers together include (1) a thermoplastic polyurethane; (2) an anhydride-modified ethylene vinyl acetate copolymer having a melt index of from 4.5 to 5; (3) a blend of 50 weight percent ethylene vinyl acetate copolymer having a vinyl acetate content of 28 weight percent and a melt index of 6, and 50 weight percent ethylene acrylic acid having an acrylic acid content of 6 weight percent and a melt index of 5.5; (4) a blend of 50 weight percent anhydride-modified ethylene n-butyl acrylate having an n-butyl content of 17.7 weight percent, an anhydride content of 3.1 weight percent, an acid index of 19 and a melt index of 5 and 50 weight percent ethylene acrylic ester having an acrylic ester content of from 26 to 30 weight percent and a
  • an adhesive is considered to bond well to a polymer layer if it has a peel strength of at least 1.5 pounds per inch, as determined by a 90 degree peel technique.
  • the 90 degree peel technique comprises coextruding a 0.003 to 0.004-inch tie layer onto a one-inch PVDC film which is approximately 0.055 to 0.080 inches thick and then pulling the tie layer at a 90 degree angle and at a speed of 10 inches/minute away from the PVDC film. The force needed to pull the tie layer away from the PVDC film is recorded as the peel strength of the tie layer in pounds per inch.
  • two polymer layers are considered "effectively tied together" if they do not delaminate or readily separate during processing or shipping and handling of the multilayer structure.
  • dissimilar high melting point polymer refers to polymers which are not chemically similar or identical to polyvinylidene chloride polymers or copolymers and have a melting point of at least 380°C.
  • carrier polymer refers to polymers displaying the ability to restrict the passage of gases, such as oxygen, carbon dioxide or moisture vapors.
  • a polymer is considered to be a good oxygen barrier if its oxygen transmission rate is below 70 cc/m7mil thickness/per 24 hours/atm, as measured according to the procedures of ASTM
  • vinylidene chloride polymer encompasses homopolymers of vinylidene chloride and also copolymers, and terpolymers thereof, wherein the major component is vinylidene chloride and the remainder is one or more monoethylenically unsaturated comonomer copolymerizable therewith.
  • Monoethylenically unsaturated monomers which can be employed in the practice of the present invention for preparing the vinylidene chloride polymers and vinyl chloride polymers include vinyl chloride, vinylidene chloride, alkyl acrylates, alkyl methacrylates, acrylic acid, methacrylic acid, itaconic acid, acrylonitrile, and methacrylonitrile.
  • Preferred monoethylenically unsaturated monomers include acrylonitrile, methacrylonitrile, alkyl acrylates, and alkyl methacrylates. More preferred monoethylenically unsaturated monomers include acrylonitrile, methacrylonitrile, and the alkyl acrylates and alkyl methacrylates having from 1 to 8 carbon atoms per alkyl group. Most preferably, the alkyl acrylates and alkyl methacrylates are methyl acrylates, ethyl acrylates, and methyl methacrylates. The most preferred monoethylenically unsaturated monomer is methyl acrylate.
  • Most preferred vinylidene chloride polymers include polymers formed from 91 to 94 weight percent vinylidene chloride and from 6 to 9 weight percent of methyl acrylate and polymers formed from 80 to 85 weight percent vinylidene chloride and from 15 to 20 weight percent vinyl chloride.
  • Vinylidene chloride polymers are known and are commercially available. Processes for preparing them, such as by emulsion or suspension polymerization process, are also familiar to persons of ordinary skill in the art. See, for example, U.S. Patents 2,558,728; 3,007,903 and 3,879,359
  • the high density polyethylene (HDPE) which can be employed in the practice of the present invention for preparing the three-layer structure has a density of at least about 0.94 grams per cubic centimeter (g/cc) (ASTM Test Method D-1505).
  • HDPE is commonly produced using techniques similar to the preparation of linear low density polyethylenes. Such techniques are described in U.S.
  • Patents 2,825,721 ; 2,993,876; 3,250,825 and 4,204,050 The preferred HDPE employed in the practice of the present invention has a density of from 0.94 to 0.99 g/cc and a melt index of from 0.01 to 35 grams per 10 minutes as determined by ASTM Test Method
  • Polyamides which can be employed in the practice of the present invention for preparing the three-layer structure include the various grades of nylon having a melting point of at least 380°F, such as nylon 6, nylon 6/66.
  • Nylon 6 and nylon 6/66 are commercially available from BASF as ULTRAMIDTM B 36 and ULTRAMIDTM C 35, respectively.
  • Cast extrusion grade nylon 6 (lower viscosity) and blown extrusion grade nylon 6 (higher viscosity) are commercially available from Allied Signal as CAPRONTM B73WP and CAPRONTM B 135 WP, respectively.
  • Polypropylenes which can be employed in the practice of the present invention for preparing the three-layer structure have a melt flow of from 0.5 to 10 g/10 minutes (as determined in accordance with ASTM D1238).
  • Polypropylene copolymers which can be employed in the practice of the present invention for preparing the three-layer structure have a melt flow of from 0.5 to 10 g/10 minutes (as determined in accordance with ASTM D1238).
  • Propylene copolymers having a melt index of 6.5 are commercially available from Montell as PROFAXTM SA-861.
  • Ethylene vinyl acetate copolymers (EVA) having a vinyl acetate content of from 18 to 28 weight percent and a melt index of from 6 to 8 are commercially available from E.I. du Pont de Nemours & Co. as ELVAXTM 3174 and ELVAXTM 3175LG.
  • Ethylene acrylic ester copolymers having an acrylic ester content of from 23 to 30 weight percent and a melt index of from 6 to 8 are commercially available from Elf Atochem as LOTRYLTM 24 MA07 and LOTRYLTM 28 MA07.
  • Ethylene methyl acrylates having a methyl acrylate content of 24 weight percent and a melt index of 10 are commercially available from Chevron as EMACTM SP.
  • Anhydride-grafted EVAs having a melt index of 3.7 are commercially available from Elf Atochem as OREVACTM 18211.
  • Anhydride-modified ethylene vinyl acetate copolymers having a melt index of from 4.5 to 5.7 are commercially available from Equistar as PLEXARTM 5298 and from E.I. du Pont de Nemours & Co as BYNELTM CXA 3860.
  • Anhydride-modified ethylene n-butyl acrylates having an n-butyl content of 17.7 weight percent, an anhydride content of 3.1 weight percent, an acid index of 19 and a melt index of 5 are commercially available from Elf Atochem as LOTADERTM 3410.
  • Ethylene vinyl acetate carbon monoxide terpolymers having a melt index of 7.5 are commercially available from E.I. du Pont de Nemours & Co as ELVALOYTM HP-441.
  • Anhydride-modified polypropylenes having a melt index of 4 are commercially available from Elf Atochem as OREVACTM 18707.
  • Ethylene acrylic acids having an acrylic acid content of 6 percent by weight and a melt index of 5.5 are commercially available from The Dow Chemical Company as PRIMACORTM 3330.
  • Thermoplastic polyurethanes which can be employed as an adhesive in the practice of the present invention for preparing the three-layer structure are soft thermoplastic polyurethanes having low melting points and are commercially available from B.F. Goodrich as ESTANETM 58224.
  • the multilayer structures described above have only three layers which are the vinylidene chloride polymer (PVDC) layer (first layer), the dissimilar high melting point polymer layer (second layer) and the tie layer (third layer) which ties the first and second layers together, additional layers formed from other polymers can be included in the three-layer structure, with or without the use of an adhesive, to form a multilayer structure having more than three layers.
  • PVDC vinylidene chloride polymer
  • second layer dissimilar high melting point polymer
  • tie layer third layer which ties the first and second layers together
  • additional layers formed from other polymers can be included in the three-layer structure, with or without the use of an adhesive, to form a multilayer structure having more than three layers.
  • a five-layer structure can be formed by adding a polymer layer (Layer 4) on top of the first layer and another polymer layer (Layer 5) on top of the second layer, with or without an adhesive layer, and a six- or a seven-layer structure can be formed by further adding another polymer layer (Layer 6) on top of the fourth layer and/or another polymer layer (Layer 7) on top of the fifth layer.
  • Layers 4, 5, 6 and 7 can be formed from the same or different polymers.
  • Such polymers can be polyolefins, polyamides, polymers based on aromatic monomers, and chlorinated polyolefins.
  • the multilayer structures of the present invention can have the following configurations:
  • Polyolefins which can be employed in the practice of the present invention for forming the fourth, fifth, sixth and/or seventh layer of the multilayer structure of the present invention include, for example, low density polyethylene, linear low density polyethylene, very low density polyethylene, polypropylene (PP), polybutene, ethylene/vinyl acetate copolymers, ethylene/propylene copolymers, ethylene/butene-1 copolymers and polyethylene terephthalates and copolymers thereof.
  • PP polypropylene
  • PP polybutene
  • ethylene/vinyl acetate copolymers ethylene/propylene copolymers
  • ethylene/butene-1 copolymers ethylene terephthalates and copolymers thereof.
  • Polyolefins based on aromatic monomers which can be employed in the practice of the present invention for forming the fourth, fifth, sixth and/or seventh layer of the multilayer structure of the present invention include polystyrene, polymethylstyrene, polyethylstyrene, styrene/methylstyrene copolymer, and styrene/chlorostyrene copolymer.
  • Polyamides which can be employed in the practice of the present invention for forming the fourth, fifth, sixth and/or seventh layer of the multilayer structure of the present invention include the various grades of nylons described previously and also those having a melting point below about 320°F (160°C), such as nylon 6/12 copolymer having about 60 weight percent nylon 6 and 40 weight percent nylon 12 and a melting point of 135°C to 145°C.
  • the thickness of the multilayer structures of the present invention is variable within wide limits, depending on the contemplated application.
  • the multilayer structure of the present invention has a thickness of from 0.05 to 200 mils, preferably from 1 to 100 mils, most preferably, from 2 to 80 mils, with the PVDC polymer layer having a thickness of from 0.005 to 20 mils, preferably from 0.1 to 10 mils, most preferably, from 0.2 to 1.0 mils.
  • the multilayer structures of the present invention can be formed using conventional coextrusion techniques such as blown coextrusion, feedblock coextrusion, multimanifold die coextrusion, or combinations of the two; co-injection molding; extrusion molding; casting; blowing; blow molding; and laminating.
  • coextrusion techniques such as blown coextrusion, feedblock coextrusion, multimanifold die coextrusion, or combinations of the two; co-injection molding; extrusion molding; casting; blowing; blow molding; and laminating.
  • the multilayer structures of the present invention are particularly suited for fabrication into rigid and flexible containers used for the preservation of food, drink, medicine and other perishables.
  • Such containers should have good mechanical properties, as well as low gas permeabilities to, for example, oxygen, carbon dioxide, water vapor, odor bodies or flavor bodies, hydrocarbons or agricultural chemicals.
  • a tie layer (EVA 28 percent, Ml 6), approximately 0.055 to 0.08 inch thick, was coextruded onto a one-inch wide SARAN polymer layer. The process was repeated by coextruding the tie layer onto a layer of nylon 6, a high melting point polymer. The peel strengths of the tie layer to both SARAN and nylon layers were then tested by a 90 degree peel technique. The results of the test are shown in Table I.
  • Example 2 The procedure of Example 1 was followed except that the tie layer described in Example 1 was coextruded onto a layer of HDPE 4452, a high density polyethylene having a melt index of 8 and manufactured by The Dow Chemical Company. The peel strengths of the tie layer to both SARAN and HDPE layers were then tested by a 90 degree peel technique. The results of the test are shown in Table I.
  • Example 3 The procedure of Example 1 was followed except that the tie layer described in Example 1 was coextruded onto a layer of HDPE 4452, a high density polyethylene having a melt index of 8 and manufactured by The Dow Chemical Company. The peel strengths of the tie layer to both SARAN and HDPE layers were then tested by a 90 degree peel technique. The results of the test are shown in Table I. Example 3
  • tie layers were individually coextruded with a SARAN layer. The process was repeated by individually coextruding each tie layer with a high melting point polymer, such as a polyamide, polypropylene or propylene copolymer and a high density polyethylene.
  • a high melting point polymer such as a polyamide, polypropylene or propylene copolymer and a high density polyethylene.
  • the peel strengths of the tie layers are shown in Table I. A peel strength of less than 2 pounds per inch is considered inadequate to bond the tie layer to each of the two layers.
  • the tie layers and the high melting point polymers are described in Table I.

Abstract

Multilayer barrier structures comprising a first layer comprising a vinylidene chloride polymer, a second layer comprising a dissimilar high melting point polymer and a tie layer disposed between the first and second layers, the tie layer comprising an adhesive which bonds well to both the first layer and the second layer and effectively ties the two layers together.

Description

MULTILAYER BARRIER STRUCTURES AND PROCESS FOR PREPARING THE SAME
This invention relates to a multilayer structure, and more particularly to a multilayer structure comprising a layer of a vinylidene chloride polymer.
While a vinylidene chloride polymer film or sheet provides high gas and water barrier properties in packaging materials or other containers, it does not provide such desirable mechanical properties as good abrasion resistance, high tensile strength and high impact strength. One approach in solving this problem is to provide a multilayer structure wherein one layer comprises a vinylidene chloride polymer and another layer comprises a polymer which provides the requisite good mechanical properties in the multilayer structure. Although many types of thermoplastic polymers possess excellent mechanical properties, they do not readily bond to other types of polymers. For example, high density polyethylene, polypropylene and nylon are typical resins used for toughness, but they are incompatible with vinylidene chloride polymer resins and, therefore, film layers made from these resins do not readily bond to the vinylidene chloride polymer layer. It is known that incompatible polymer layers can be joined together by using a tie layer or adhesive layer between the two layers. However, a tie layer can be compatible with one of the two incompatible layers but not with the other layer. For example, a tie layer of EVA (9 percent VA content, 7 melt index) bonds well to an HDPE layer but not to a vinylidene chloride polymer layer. It would be desirable to provide adhesives that work especially effectively for a given combination of incompatible or dissimilar film layers in a multilayer film.
In a first aspect, the present invention is a three-layer barrier structure comprising a first layer comprising a vinylidene chloride polymer (PVDC), a second layer comprising a dissimilar high melting point polymer (HMPP) and a tie layer disposed between the first and second layers, the tie layer comprising an adhesive which bonds well to both the first layer and the second layer and effectively ties the two layers together.
In a second aspect, the present invention is a multilayer structure comprising the three-layer structure of the first aspect and other polymer layers added to the three-layer structure. Such other polymers include polyolefins, polyamides, polymers based on aromatic monomers, and chlorinated polyolefins. In a third aspect, the present invention is a process for preparing the multilayer structure of the first aspect comprising providing a first layer comprising a vinylidene chloride polymer (PVDC), adhering to the first layer a second layer comprising a dissimilar high melting point polymer (HMPP) by using a tie layer comprising an adhesive which bonds well to both the first layer and the second layer and effectively ties the two layers together.
In a fourth aspect, the present invention is a process for preparing the multilayer structure of the first aspect comprising coextruding a first layer comprising a vinylidene chloride polymer (PVDC), a second layer comprising a dissimilar high melting point polymer (HMPP) and a tie layer disposed between the first and second layers, the tie layer comprising an adhesive which bonds well to both the first layer and the second layer and effectively ties the two layers together.
The multilayer structures of the present invention are particularly suited for fabrication into flexible and rigid containers used for the preservation of food, drink, medicine and other perishables. Such containers should have good mechanical properties, as well as low gas permeabilities too, for example, oxygen, carbon dioxide, water vapor, odor bodies or flavor bodies, hydrocarbons or agricultural chemicals.
Adhesives which can be employed in the practice of the present invention for preparing the multilayer structures include, in general, ethylene vinyl acetate copolymers, ethylene/ethyl acrylic acid ester copolymers, ionomers, modified polyolefins as described in U.S. Patent 5,443,874, acrylic-based terpolymer adhesives as described in U.S. Patent 3,753,769 and adhesives formed by reacting an epoxy resin and an acidified aminoethylated vinyl polymer as described in U.S. Patent 4,447,494.
More specifically, if it is desired to prepare a three-layer structure having a first layer of a vinylidene chloride polymer tied to a second layer of a high density polyethylene, the adhesives which can be employed in the practice of the present invention to effectively tie the two layers together include (1) an ethylene vinyl acetate copolymer (EVA) having a vinyl acetate content of from 9 to 28 weight percent and a melt index of from 2 to 8; (2) an ethylene acrylic ester copolymer having an acrylic ester content of from 23 to 30 weight percent and a melt index of from 6 to 8; (3) an ethylene methyl acrylate having a methyl acrylate content of 24 weight percent and a melt index of 10; (4) an anhydride- modified ethylene vinyl acetate copolymer having a melt index of from 4.5 to 5; (5) a blend of from 60 to 70 weight percent ethylene vinyl acetate copolymer having a vinyl acetate content WO 01/12436 PCT/US0O/2O2O5
of 28 weight percent and a melt index of from 6 to 7 and from 30 to 40 weight percent polypropylene copolymer having a melt flow ratio of 6.5; and (6) a blend of 50 weight percent anhydride-modified ethylene n-butyl acrylate having an n-butyl content of 17.7 weight percent, an anhydride content of 3.1 weight percent, an acid index of 19, and a melt index of 5, and 50 weight percent ethylene acrylic ester having an acrylic ester content of from 26 to 30 weight percent and a melt index of 7.
If it is desired to prepare a three-layer structure having a layer of a vinylidene chloride polymer tied to a layer of a polypropylene or polypropylene copolymer, the adhesives which can be employed to effectively tie the two layers together include (1) an ethylene vinyl acetate copolymer (EVA) having a vinyl acetate content of from 9 to 28 weight percent and a melt index of from 2 to 8; (2) an ethylene acrylic ester copolymer having an acrylic ester content of from 12 to 30 weight percent and a melt index of from 6 to 8; (3) an ethylene methyl acrylate having a methyl acrylate content of 24 weight percent and a melt index of 10; (4) an anhydride-modified ethylene vinyl acetate copolymer having a melt index of from 2 to 5.7; (5) a blend of from 50 to 70 weight percent ethylene vinyl acetate copolymer having a vinyl acetate content of 28 weight percent and a melt index of from 6 to 7 and from 30 to 50 weight percent polypropylene copolymer having a melt flow ratio of 6.5; (6) a blend of 50 weight percent anhydride-modified ethylene n-butyl acrylate having an n-butyl content of 17.7 weight percent, an anhydride content of 3.1 weight percent, an acid index of 19 and a melt index of 5, and 50 weight percent ethylene acrylic ester having an acrylic ester content of from 26 to 30 weight percent and a melt index of 7; and (7) a blend of 50 weight percent anhydride-modified polypropylene having a melt index of 4, and 50 weight percent anhydride-modified ethylene vinyl acetate copolymer having a melt index of 3.7 to 4.6.
If it is desired to prepare a three-layer structure having a layer of a vinylidene chloride polymer tied to a layer of a high melting point polyamide, the adhesives which can be employed in the practice of the present invention to effectively tie the two layers together include (1) a thermoplastic polyurethane; (2) an anhydride-modified ethylene vinyl acetate copolymer having a melt index of from 4.5 to 5; (3) a blend of 50 weight percent ethylene vinyl acetate copolymer having a vinyl acetate content of 28 weight percent and a melt index of 6, and 50 weight percent ethylene acrylic acid having an acrylic acid content of 6 weight percent and a melt index of 5.5; (4) a blend of 50 weight percent anhydride-modified ethylene n-butyl acrylate having an n-butyl content of 17.7 weight percent, an anhydride content of 3.1 weight percent, an acid index of 19 and a melt index of 5 and 50 weight percent ethylene acrylic ester having an acrylic ester content of from 26 to 30 weight percent and a melt index of 7; (5) a blend of from 30 to 40 weight percent ethylene acrylic acid having an acrylic acid content of 6 weight percent and a melt index of 7 and from 60 to 70 weight percent anhydride-modified EVA having a melt index of 5.7; (6) a blend of 50 weight percent anhydride-modified ethylene n-butyl acrylate having an n-butyl content of 17.7 weight percent, an anhydride content of 3.1 weight percent, an acid index of 19 and a melt index of 5, and 50 weight percent ethylene acrylic ester having an acrylic ester content of from 26 to 30 weight percent and a melt index of 7; (7) an ethylene vinyl acetate carbon monoxide terpolymer; (8) a blend of from 40 to 70 weight percent EVA having a vinyl acetate content of 28 weight percent and a melt index of 7, and 30 to 60 weight percent ethylene acrylic acid having an acrylic acid content of 6.5 weight percent and a melt index of 5.5; and (9) a blend of 50 weight percent anhydride-modified polypropylene having a melt index of 4, and 50 weight percent anhydride-modified ethylene vinyl acetate copolymer having a melt index of 3.7 to 4.6.
For the purposes of the present invention, an adhesive is considered to bond well to a polymer layer if it has a peel strength of at least 1.5 pounds per inch, as determined by a 90 degree peel technique. The 90 degree peel technique comprises coextruding a 0.003 to 0.004-inch tie layer onto a one-inch PVDC film which is approximately 0.055 to 0.080 inches thick and then pulling the tie layer at a 90 degree angle and at a speed of 10 inches/minute away from the PVDC film. The force needed to pull the tie layer away from the PVDC film is recorded as the peel strength of the tie layer in pounds per inch. For the purposes of the present invention, two polymer layers are considered "effectively tied together" if they do not delaminate or readily separate during processing or shipping and handling of the multilayer structure.
As used herein, the term "dissimilar high melting point polymer" refers to polymers which are not chemically similar or identical to polyvinylidene chloride polymers or copolymers and have a melting point of at least 380°C.
As used herein, the term "barrier polymer" refers to polymers displaying the ability to restrict the passage of gases, such as oxygen, carbon dioxide or moisture vapors. A polymer is considered to be a good oxygen barrier if its oxygen transmission rate is below 70 cc/m7mil thickness/per 24 hours/atm, as measured according to the procedures of ASTM
Method D-1434. As used herein, the term "vinylidene chloride polymer" encompasses homopolymers of vinylidene chloride and also copolymers, and terpolymers thereof, wherein the major component is vinylidene chloride and the remainder is one or more monoethylenically unsaturated comonomer copolymerizable therewith. Monoethylenically unsaturated monomers which can be employed in the practice of the present invention for preparing the vinylidene chloride polymers and vinyl chloride polymers include vinyl chloride, vinylidene chloride, alkyl acrylates, alkyl methacrylates, acrylic acid, methacrylic acid, itaconic acid, acrylonitrile, and methacrylonitrile. Preferred monoethylenically unsaturated monomers include acrylonitrile, methacrylonitrile, alkyl acrylates, and alkyl methacrylates. More preferred monoethylenically unsaturated monomers include acrylonitrile, methacrylonitrile, and the alkyl acrylates and alkyl methacrylates having from 1 to 8 carbon atoms per alkyl group. Most preferably, the alkyl acrylates and alkyl methacrylates are methyl acrylates, ethyl acrylates, and methyl methacrylates. The most preferred monoethylenically unsaturated monomer is methyl acrylate.
Most preferred vinylidene chloride polymers include polymers formed from 91 to 94 weight percent vinylidene chloride and from 6 to 9 weight percent of methyl acrylate and polymers formed from 80 to 85 weight percent vinylidene chloride and from 15 to 20 weight percent vinyl chloride.
Vinylidene chloride polymers are known and are commercially available. Processes for preparing them, such as by emulsion or suspension polymerization process, are also familiar to persons of ordinary skill in the art. See, for example, U.S. Patents 2,558,728; 3,007,903 and 3,879,359 In general, the high density polyethylene (HDPE) which can be employed in the practice of the present invention for preparing the three-layer structure has a density of at least about 0.94 grams per cubic centimeter (g/cc) (ASTM Test Method D-1505). HDPE is commonly produced using techniques similar to the preparation of linear low density polyethylenes. Such techniques are described in U.S. Patents 2,825,721 ; 2,993,876; 3,250,825 and 4,204,050. The preferred HDPE employed in the practice of the present invention has a density of from 0.94 to 0.99 g/cc and a melt index of from 0.01 to 35 grams per 10 minutes as determined by ASTM Test Method
D-1238.
Polyamides which can be employed in the practice of the present invention for preparing the three-layer structure include the various grades of nylon having a melting point of at least 380°F, such as nylon 6, nylon 6/66. Nylon 6 and nylon 6/66 are commercially available from BASF as ULTRAMID™ B 36 and ULTRAMID™ C 35, respectively. Cast extrusion grade nylon 6 (lower viscosity) and blown extrusion grade nylon 6 (higher viscosity) are commercially available from Allied Signal as CAPRON™ B73WP and CAPRON™ B 135 WP, respectively.
Polypropylenes which can be employed in the practice of the present invention for preparing the three-layer structure have a melt flow of from 0.5 to 10 g/10 minutes (as determined in accordance with ASTM D1238).
Polypropylene copolymers which can be employed in the practice of the present invention for preparing the three-layer structure have a melt flow of from 0.5 to 10 g/10 minutes (as determined in accordance with ASTM D1238). Propylene copolymers having a melt index of 6.5 are commercially available from Montell as PROFAX™ SA-861. Ethylene vinyl acetate copolymers (EVA) having a vinyl acetate content of from 18 to 28 weight percent and a melt index of from 6 to 8 are commercially available from E.I. du Pont de Nemours & Co. as ELVAX™ 3174 and ELVAX™ 3175LG.
Ethylene acrylic ester copolymers having an acrylic ester content of from 23 to 30 weight percent and a melt index of from 6 to 8 are commercially available from Elf Atochem as LOTRYL™ 24 MA07 and LOTRYL™ 28 MA07.
Ethylene methyl acrylates having a methyl acrylate content of 24 weight percent and a melt index of 10 are commercially available from Chevron as EMAC™ SP.
Anhydride-grafted EVAs having a melt index of 3.7 are commercially available from Elf Atochem as OREVAC™ 18211. Anhydride-modified ethylene vinyl acetate copolymers having a melt index of from 4.5 to 5.7 are commercially available from Equistar as PLEXAR™ 5298 and from E.I. du Pont de Nemours & Co as BYNEL™ CXA 3860.
Anhydride-modified ethylene n-butyl acrylates having an n-butyl content of 17.7 weight percent, an anhydride content of 3.1 weight percent, an acid index of 19 and a melt index of 5 are commercially available from Elf Atochem as LOTADER™ 3410.
Ethylene vinyl acetate carbon monoxide terpolymers having a melt index of 7.5 are commercially available from E.I. du Pont de Nemours & Co as ELVALOY™ HP-441.
Anhydride-modified polypropylenes having a melt index of 4 are commercially available from Elf Atochem as OREVAC™ 18707. Ethylene acrylic acids having an acrylic acid content of 6 percent by weight and a melt index of 5.5 are commercially available from The Dow Chemical Company as PRIMACOR™ 3330.
Thermoplastic polyurethanes which can be employed as an adhesive in the practice of the present invention for preparing the three-layer structure are soft thermoplastic polyurethanes having low melting points and are commercially available from B.F. Goodrich as ESTANE™ 58224.
Although the multilayer structures described above have only three layers which are the vinylidene chloride polymer (PVDC) layer (first layer), the dissimilar high melting point polymer layer (second layer) and the tie layer (third layer) which ties the first and second layers together, additional layers formed from other polymers can be included in the three-layer structure, with or without the use of an adhesive, to form a multilayer structure having more than three layers. For example, a five-layer structure can be formed by adding a polymer layer (Layer 4) on top of the first layer and another polymer layer (Layer 5) on top of the second layer, with or without an adhesive layer, and a six- or a seven-layer structure can be formed by further adding another polymer layer (Layer 6) on top of the fourth layer and/or another polymer layer (Layer 7) on top of the fifth layer. Layers 4, 5, 6 and 7 can be formed from the same or different polymers. Such polymers can be polyolefins, polyamides, polymers based on aromatic monomers, and chlorinated polyolefins. Thus, the multilayer structures of the present invention can have the following configurations:
Three-laver structure:
PVDC/Tie Layer/High Melting Point Polymer (HMPP)
Five-layer structure: Layer 4/PVDC/Tie laver/HMPP/Laver 5
Six-laver structure:
Layer 6/Layer 4/PVDC/Tie layer/HMPP/Layer 5
Seven-layer structure:
Layer 6/Layer 4/PVDC/Tie layer/HMPP/Layer 5/Layer 7 Polyolefins which can be employed in the practice of the present invention for forming the fourth, fifth, sixth and/or seventh layer of the multilayer structure of the present invention include, for example, low density polyethylene, linear low density polyethylene, very low density polyethylene, polypropylene (PP), polybutene, ethylene/vinyl acetate copolymers, ethylene/propylene copolymers, ethylene/butene-1 copolymers and polyethylene terephthalates and copolymers thereof.
Polyolefins based on aromatic monomers which can be employed in the practice of the present invention for forming the fourth, fifth, sixth and/or seventh layer of the multilayer structure of the present invention include polystyrene, polymethylstyrene, polyethylstyrene, styrene/methylstyrene copolymer, and styrene/chlorostyrene copolymer.
Polyamides which can be employed in the practice of the present invention for forming the fourth, fifth, sixth and/or seventh layer of the multilayer structure of the present invention include the various grades of nylons described previously and also those having a melting point below about 320°F (160°C), such as nylon 6/12 copolymer having about 60 weight percent nylon 6 and 40 weight percent nylon 12 and a melting point of 135°C to 145°C.
The thickness of the multilayer structures of the present invention is variable within wide limits, depending on the contemplated application. In general, the multilayer structure of the present invention has a thickness of from 0.05 to 200 mils, preferably from 1 to 100 mils, most preferably, from 2 to 80 mils, with the PVDC polymer layer having a thickness of from 0.005 to 20 mils, preferably from 0.1 to 10 mils, most preferably, from 0.2 to 1.0 mils.
The multilayer structures of the present invention can be formed using conventional coextrusion techniques such as blown coextrusion, feedblock coextrusion, multimanifold die coextrusion, or combinations of the two; co-injection molding; extrusion molding; casting; blowing; blow molding; and laminating.
The multilayer structures of the present invention are particularly suited for fabrication into rigid and flexible containers used for the preservation of food, drink, medicine and other perishables. Such containers should have good mechanical properties, as well as low gas permeabilities to, for example, oxygen, carbon dioxide, water vapor, odor bodies or flavor bodies, hydrocarbons or agricultural chemicals.
The present invention is illustrated in further detail by the following examples. The examples are for the purposes of illustration only, and are not to be construed as limiting the scope of the present invention. All parts and percentages are by weight unless otherwise specifically noted.
Example 1
A tie layer (EVA 28 percent, Ml 6), approximately 0.055 to 0.08 inch thick, was coextruded onto a one-inch wide SARAN polymer layer. The process was repeated by coextruding the tie layer onto a layer of nylon 6, a high melting point polymer. The peel strengths of the tie layer to both SARAN and nylon layers were then tested by a 90 degree peel technique. The results of the test are shown in Table I.
Example 2 The procedure of Example 1 was followed except that the tie layer described in Example 1 was coextruded onto a layer of HDPE 4452, a high density polyethylene having a melt index of 8 and manufactured by The Dow Chemical Company. The peel strengths of the tie layer to both SARAN and HDPE layers were then tested by a 90 degree peel technique. The results of the test are shown in Table I. Example 3
Several tie layers were individually coextruded with a SARAN layer. The process was repeated by individually coextruding each tie layer with a high melting point polymer, such as a polyamide, polypropylene or propylene copolymer and a high density polyethylene. The peel strengths of the tie layers are shown in Table I. A peel strength of less than 2 pounds per inch is considered inadequate to bond the tie layer to each of the two layers. The tie layers and the high melting point polymers are described in Table I.
The processing conditions used in the above Examples are shown in Tables II and III. The materials used in the Examples are described in Table IV.
Table I
Figure imgf000011_0001
Figure imgf000012_0001
Table
Figure imgf000012_0002
Table
Figure imgf000013_0001
Table IV
Figure imgf000013_0002
Figure imgf000014_0001

Claims

CLAIMS:
1. A multilayer barrier structure comprising a first layer comprising a vinylidene chloride polymer, a second layer comprising a dissimilar high melting point polymer and a tie layer disposed between the first and second layers, the tie layer comprising an adhesive which bonds well to both the first layer and the second layer and effectively ties the two layers together.
2. The multilayer barrier structure of Claim 1 wherein the second layer comprises a high density polyethylene and the tie layer comprises (1) an ethylene vinyl acetate copolymer (EVA) having a vinyl acetate content of from 9 to 28 weight percent and a melt index of from 2 to 8; (2) an ethylene acrylic ester copolymer having an acrylic ester content of from 23 to 30 weight percent and a melt index of from 6 to 8; (3) an ethylene methyl acrylate having a methyl acrylate content of 24 weight percent and a melt index of 10; (4) an anhydride-modified ethylene vinyl acetate copolymer having a melt index of from 4.5 to 5; (5) a blend of from 60 to 70 weight percent ethylene vinyl acetate copolymer having a vinyl acetate content of 28 weight percent and a melt index of from 6 to 7 and from 30 to 40 weight percent polypropylene copolymer having a melt flow ratio of 6.5; or (6) a blend of 50 weight percent anhydride-modified ethylene n-butyl acrylate having an n-butyl content of 17.7 weight percent, an anhydride content of 3.1 weight percent, an acid index of 19 and a melt index of 5, and 50 weight percent ethylene acrylic ester having an acrylic ester content of from 26 to 30 weight percent and a melt index of 7.
3. The multilayer barrier structure of Claim 1 wherein the second layer comprises a polypropylene or polypropylene copolymer and the tie layer comprises (1) an ethylene vinyl acetate copolymer (EVA) having a vinyl acetate content of from 9 to 28 weight percent and a melt index of from 2 to 8; (2) an ethylene acrylic ester copolymer having an acrylic ester content of from 12 to 30 weight percent and a melt index of from 6 to 8; (3) an ethylene methyl acrylate having a methyl acrylate content of 24 weight percent and a melt index of 10; (4) an anhydride-modified ethylene vinyl acetate copolymer having a melt index of from 2 to 5.7; (5) a blend of from 50 to 70 weight percent ethylene vinyl acetate copolymer having a vinyl acetate content of 28 weight percent and a melt index of from 6 to 7 and from 30 to 50 weight percent polypropylene copolymer having a melt flow ratio of 6.5; (6) a blend of 50 weight percent anhydride-modified ethylene n-butyl acrylate having an n-butyl content of 17.7 weight percent, an anhydride content of 3.1 weight percent, an acid index of 19 and a melt index of 5, and 50 weight percent ethylene acrylic ester having an acrylic ester content of from 26 to 30 weight percent and a melt index of 7; and (7) a blend of 50 weight percent anhydride-modified polypropylene having a melt index of 4, and 50 weight percent anhydride-modified ethylene vinyl acetate copolymer having a melt index of 3.7 to 4.6.
4. The multilayer barrier structure of Claim 1 wherein the second layer comprises a high melting point polyamide and the tie layer comprises (1) a thermoplastic polyurethane; (2) an anhydride-modified ethylene vinyl acetate copolymer having a melt index of from 4.5 to 5; (3) a blend of 50 weight percent ethylene vinyl acetate copolymer having a vinyl acetate content of 28 weight percent and a melt index of 6, and 50 weight percent ethylene acrylic acid having an acrylic acid content of 6 weight percent and a melt index of 5.5; (4) a blend of 50 weight percent anhydride-modified ethylene n-butyl acrylate having an n-butyl content of 17.7 weight percent, an anhydride content of 3.1 weight percent, an acid index of 19 and a melt index of 5 and 50 weight percent ethylene acrylic ester having an acrylic ester content of from 26 to 30 weight percent and a melt index of 7; (5) a blend of from 30 to 40 weight percent ethylene acrylic acid having an acrylic acid content of 6 weight percent and a melt index of 7 and from 60 to 70 weight percent anhydride-modified EVA having a melt index of 5.7; (6) a blend of 50 weight percent anhydride-modified ethylene n- butyl acrylate having an n-butyl content of 17.7 weight percent, an anhydride content of 3.1 weight percent, an acid index of 19 and a melt index of 5, and 50 weight percent ethylene acrylic ester having an acrylic ester content of from 26 to 30 weight percent and a melt index of 7; (7)an ethylene vinyl acetate carbon monoxide terpolymer; (8) a blend of from 40 to 70 weight percent EVA having a vinyl acetate content of 28 weight percent and a melt index of
7, and 30 to 60 weight percent ethylene acrylic acid having an acrylic acid content of 6.5 weight percent and a melt index of 5.5; or (9) a blend of 50 weight percent anhydride- modified polypropylene having a melt index of 4, and 50 weight percent anhydride-modified ethylene vinyl acetate copolymer having a melt index of 3.7 to 4.6.
5. The multilayer barrier structure of Claim 1 further comprising one or more polymer layers adhered to the outer surface of the first layer and/or the second layer
6. The multilayer barrier structure of Claim 2 further comprising one or more polymer layers adhered to the outer surface of the first layer and/or the second layer
7. The multilayer barrier structure of Claim 3 further comprising one or more polymer layers adhered to the outer surface of the first layer and/or the second layer
8. The multilayer barrier structure of Claim 4 further comprising one or more polymer layers adhered to the outer surface of the first layer and/or the second layer
9. A process for preparing the multilayer structure of Claim 1 which comprises providing a first layer comprising a vinylidene chloride polymer and adhering to the first layer a second layer comprising a dissimilar high melting point polymer by using a tie layer comprising an adhesive which bonds well to both the first layer and the second layer and effectively ties the two layers together.
10. A process for preparing the multilayer structure of Claim 1 comprising coextruding a first layer comprising a vinylidene chloride polymer, a second layer comprising a dissimilar high melting point polymer and a tie layer disposed between the first and second layers, the tie layer comprising an adhesive which bonds well to both the first layer and the second layer and effectively ties the two layers together.
PCT/US2000/020205 1999-08-17 2000-07-25 Multilayer barrier structures and process for preparing the same WO2001012436A2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU63726/00A AU6372600A (en) 1999-08-17 2000-07-25 Multilayer barrier structures and process for preparing the same

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US37573399A 1999-08-17 1999-08-17
US09/375,733 1999-08-17

Publications (2)

Publication Number Publication Date
WO2001012436A2 true WO2001012436A2 (en) 2001-02-22
WO2001012436A3 WO2001012436A3 (en) 2001-06-14

Family

ID=23482100

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2000/020205 WO2001012436A2 (en) 1999-08-17 2000-07-25 Multilayer barrier structures and process for preparing the same

Country Status (3)

Country Link
AR (1) AR025301A1 (en)
AU (1) AU6372600A (en)
WO (1) WO2001012436A2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180327638A1 (en) * 2017-05-12 2018-11-15 3M Innovative Properties Company Adhesive tapes

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3673050A (en) * 1970-02-05 1972-06-27 Dow Chemical Co A laminate of a barrier layer enclosed in rigid high density polyolefin layers
EP0311871A2 (en) * 1987-10-13 1989-04-19 Miles Inc. Coextrusion structures
EP0435790A2 (en) * 1989-12-28 1991-07-03 American National Can Company Multiple layer sheet materials and packages, and methods and apparatus for making the same
US5296554A (en) * 1991-10-28 1994-03-22 Showa Denko K.K. Adhesive resin composition

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3673050A (en) * 1970-02-05 1972-06-27 Dow Chemical Co A laminate of a barrier layer enclosed in rigid high density polyolefin layers
EP0311871A2 (en) * 1987-10-13 1989-04-19 Miles Inc. Coextrusion structures
EP0435790A2 (en) * 1989-12-28 1991-07-03 American National Can Company Multiple layer sheet materials and packages, and methods and apparatus for making the same
US5296554A (en) * 1991-10-28 1994-03-22 Showa Denko K.K. Adhesive resin composition

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180327638A1 (en) * 2017-05-12 2018-11-15 3M Innovative Properties Company Adhesive tapes
US10774245B2 (en) * 2017-05-12 2020-09-15 3M Innovative Properties Company Adhesive tapes
US10870780B2 (en) 2017-05-12 2020-12-22 3M Innovative Properties Company Adhesive tapes
US11578240B2 (en) 2017-05-12 2023-02-14 3M Innovative Properties Company Adhesive tapes

Also Published As

Publication number Publication date
WO2001012436A3 (en) 2001-06-14
AU6372600A (en) 2001-03-13
AR025301A1 (en) 2002-11-20

Similar Documents

Publication Publication Date Title
EP0994776B1 (en) Multilayer fluoropolymer films with improved adhesion
US5085927A (en) Stretch film cling enhancement by addition of elastomers
US4647509A (en) Thermoformable multilayer barrier structures
US4755419A (en) Oxygen barrier oriented shrink film
US4977022A (en) Barrier stretch film
US8329276B2 (en) Easy-open reclosable films having an interior frangible interface and articles made therefrom
AU2009260627B2 (en) Innerliner with nylon skin layer
US4788105A (en) Oxygen barrier laminates
US4939076A (en) Barrier stretch film
US6740412B2 (en) Polymeric adhesive and structures with multiple polymeric layers, their process of preparation and their use
CA2530824C (en) Heat sealable and peelable film
CA1132951A (en) Coextruded laminar thermoplastic bags
WO1989008556A1 (en) Multilayered sheets having excellent adhesion
EP0479457A1 (en) Adhesive or coating compositions and their uses
EP0158533A2 (en) Heat-resistant laminate film
JPS5949191B2 (en) resin laminate
NO831791L (en) MULTILAYER THERMOPLAST FILM
EP0791640B1 (en) Extrudable resin for polystyrene and laminate
WO2001012436A2 (en) Multilayer barrier structures and process for preparing the same
JP2697097B2 (en) Multilayer container
US20040038055A1 (en) Multi-layer, deep-drawable and sealable film
JPH01269535A (en) Multilayer sheet material for packaging
JPH073109A (en) Polyamide resin composition and laminate made by using the same
JPS59152852A (en) Laminate and manufacture thereof
JPH04300936A (en) Adhesive polymer composition and laminate produced by using the same

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A2

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY CA CH CN CR CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG UZ YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A2

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
AK Designated states

Kind code of ref document: A3

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY CA CH CN CR CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG UZ YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A3

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase in:

Ref country code: JP