Stock material or miscellaneous articles – Composite – Of addition polymer from unsaturated monomers
Reexamination Certificate
1998-07-17
2001-04-10
Thibodeau, Paul (Department: 1773)
Stock material or miscellaneous articles
Composite
Of addition polymer from unsaturated monomers
C428S520000, C428S522000, C428S034900, C428S036600, C428S910000
Reexamination Certificate
active
06214477
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a thermoplastic film containing polyolefin and polyvinyl chloride, which film can be utilized to package a wide variety of items.
BACKGROUND OF THE INVENTION
The present invention is directed to a new and useful film. Films, and especially heat shrinkable films are well known for many packaging applications.
Examples of such films are the polyolefinic films supplied commercially by Cryovac, Inc. These films have proven to be very useful in pack- aging applications where high shrink, good optics, impact resistance, tear initiation and tear propagation resistance are needed. Films of this type are disclosed in U.S. Pat. Nos. 4,551,380 and 4,643,943, both to Schoenberg, incorporated herein by reference in their entirety.
Polyvinyl chloride (hereinafter “PVC”) films are also widely used in packaging applications.
PVC films exhibit good elastic recovery, high modulus, and low shrink tension, but poor sealability, and poor tear resistance. They also carbonize during a trim sealing process.
It would be desirable to provide a film having the good sealaibility and tear resistance properties of polyolefinic films, but with the good elastic recovery, high modulus, and low shrink tension of PVC films.
SUMMARY OF THE INVENTION
In a first aspect, a multilayer film comprises a first layer, having two major surfaces, comprising polyvinyl chloride; and a second layer, adhered to a first major surface of the first layer, comprising a material selected from the group consisting of anhydride functionalized polyolefin, ethylene/vinyl acetate copolymer having a vinyl acetate content of between 10% and 35% by weight of the ethylene/vinyl acetate copolymer, ethylene/alkyl acrylate copolymer having an alkyl acrylate content of between 10% and 30% by weight of the ethylene/alkyl acrylate copolymer, ethylene/alkyl methacrylate copolymer having an alkyl methacryl- ate content of between 10% and 30% by weight of the ethylene/alkyl methacrylate copolymer, ethylene/acrylic acid copolymer having an acrylic acid content of between 10% and 30% by weight of the ethylene/acrylic acid copolymer, ethylene/methacrylic acid copolymer having a methacrylic acid content of between 10% and 30% by weight of the ethylene/methacrylic acid copolymer, and ionomer. Optionally, the film further comprises a third layer, adhered to a second major surface of the first layer, comprising any of the materials of the second layer.
In a second aspect, a multilayer film comprises a core layer, having two major surfaces, comprising a material selected from the group consisting of anhydride functionalized polyolefin, ethylene/vinyl acetate co- polymer having a vinyl acetate content of between 10% and 35% by weight of the ethylene/vinyl acetate copolymer, ethylene/alkyl acrylate copolymer having an alkyl acrylate content of between 10% and 30% by weight of the ethylene/alkyl acrylate copolymer, ethylene/alkyl methacrylate copolymer having an alkyl methacrylate content of between 10% and 30% by weight of the ethylene/alkyl methacrylate copolymer, ethylene/acrylic acid copolymer having an acrylic acid content of between 10% and 30% by weight of the ethylene/acrylic acid copolymer, ethylene/methacrylic acid copolymer having a methacrylic acid content of between 10% and 30% by weight of the ethylene/methacrylic acid copolymer, and ionomer; a first outer layer, adhered to a first major surface of the core layer, comprising polyvinyl chloride; and a second outer layer, adhered to a second major surface of the core layer, comprising polyolefin or polyvinyl chloride. The first outer layer comprising polyvinyl chloride can optionally have adhered to it, a fourth layer comprising any of the materials disclosed for the core layer.
In a third aspect, a multilayer film comprises a core layer, having two major surfaces, comprising polyvinyl chloride; two intermediate layers, each adhered to a respective major surface of the core layer, comprising a material selected from the group consisting of anhydride functionalized polyolefin, ethylene/vinyl acetate copolymer having a vinyl acetate content of between 10% and 35% by weight of the ethylene/vinyl acetate copolymer, ethylene/alkyl acrylate copolymer having an alkyl acrylate content of between 10% and 30% by weight of the ethylene/alkyl acrylate copolymer, ethylene/alkyl methacrylate copolymer having an alkyl methacrylate content of between 10% and 30% by weight of the ethylene/alkyl methacrylate copolymer, ethylene/acrylic acid copolymer having an acrylic acid content of between 10% and 30% by weight of the ethylene/acrylic acid copolymer, ethylene/methacrylic acid copolymer having a methacrylic acid content of between 10% and 30% by weight of the ethylene/methacrylic acid copolymer, and ionomer; and two outer layers, each adhered to a major surface of a respective intermediate layer, comprising polyolefin.
DEFINITIONS
“Anhydride functionalized polyolefin” (ahPO) herein refers to any form of anhydride functionality, such as the anhydride of maleic acid, itaconic acid, etc., grafted onto a polyolefin or copolymerized with a polyolefin; and optionally blended with one or more polyolefins.
“Core layer” herein refers to a central layer of a multi-layer film.
“Intermediate layer” herein refers to a layer of a multilayer film which is neither a core layer nor an outer layer.
“Ionomer” herein refers to an ionized copolymer of ethylene and a vinyl monomer with an acid group, such as copolymers of acrylic or methacrylic acid, in which the ionization is a result of replacing protons with metal ions on a portion of the acid groups on the polymer.
“Outer layer” herein refers to what is typically an outermost, surface layer of a multi-layer film, although additional layers and/or films can be optionally adhered to it.
“Polymer” herein refers to homopolymer, copolymer, terpolymer, etc. “Copolymer” herein refers to copolymer, terpolymer, etc.
All compositional percentages used herein are calculated on a “by weight” basis.
“Polyolefin” (PO) herein refers to the class or group of thermoplastic polymers derived from simple olefins, such as polyethylene (e.g. low density polyethylene and high density polyethylene), polypropylene, polybutene, etc. and includes copolymers such as ethylene/alpha-olefin copolymer; ethylene/vinyl acetate copolymer; ethylene/alkyl acrylate copolymer, ethylene/alkyl methacrylate copolymer, propylene/ethylene copolymer, and ionomer.
“Ethylene/alpha-olefin copolymer” (EAO) refers to such heterogeneous materials as linear medium density polyethylene (LMDPE), linear low density polyethylene (LLDPE), and very low and ultra low density polyethylene (VLDPE and ULDPE); as well as homogeneous polymers (HEAO) such as TAFMER™ ethylene/alpha olefin copolymers supplied by Mitsui Petrochemical Corporation and metallocene-catalyzed polymers such as EXACT™ materials supplied by Exxon, AFFINITY™ resins supplied by Dow Chemical Company, and ENGAGE™ resins supplied by DuPont Dow Elastomers. These materials generally include copolymers of ethylene with one or more comonomers selected from C
4
to C
10
alpha-olefins such as butene-1 (i.e., 1-butene), hexene-1, octene-1, etc.
“Polyvinyl chloride” is defined herein as a polymer made by the catalytic polymerization of vinyl chloride. “Polyvinyl chloride” also includes copolymers that contain at least 50% vinyl chloride. Stabilizers, and plasticizers such as epoxidized vegetable oil, dialkyl adipate, and dialkyl phthalate, are commonly used and are herein included when referring to “polyvinyl chloride”.
“Heat shrinkable” herein refers to a material which, when heated to a temperature of 180° F., will have a free shrink of 5% or greater, more preferably 10% or greater, in at least one linear direction, as measured by ASTM D 2732.
“MD” herein refers to machine direction or longitudinal direction.
“TD” herein refers to transverse direction or cross direction.
“EVA” herein refers to ethylene/vinyl acetate copolymer.
REFERENCES:
patent: 3614852 (1971-10-01), Buod
patent: 4156749 (1979-05-01), Lustig et al.
patent:
Roberts William P.
Wofford George D.
Cryovac Inc.
Quatt Mark B.
Thibodeau Paul
LandOfFree
Multilayer film with polyolefin and polyvinyl chloride does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multilayer film with polyolefin and polyvinyl chloride, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multilayer film with polyolefin and polyvinyl chloride will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2438380