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WO1998005706A1 - Film a amide gras greffe dans sa couche externe - Google Patents

Film a amide gras greffe dans sa couche externe Download PDF

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Publication number
WO1998005706A1
WO1998005706A1 PCT/US1997/013551 US9713551W WO9805706A1 WO 1998005706 A1 WO1998005706 A1 WO 1998005706A1 US 9713551 W US9713551 W US 9713551W WO 9805706 A1 WO9805706 A1 WO 9805706A1
Authority
WO
WIPO (PCT)
Prior art keywords
layer
copolymer
ethylene
film
multilayer film
Prior art date
Application number
PCT/US1997/013551
Other languages
English (en)
Inventor
Solomon Bekele
Original Assignee
Cryovac, Inc.
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 Cryovac, Inc. filed Critical Cryovac, Inc.
Priority to AU39039/97A priority Critical patent/AU3903997A/en
Publication of WO1998005706A1 publication Critical patent/WO1998005706A1/fr

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
    • B32B27/16—Layered products comprising a layer of synthetic resin specially treated, e.g. irradiated
    • 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
    • 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
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • 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
    • B32B43/00—Operations specially adapted for layered products and not otherwise provided for, e.g. repairing; Apparatus therefor
    • B32B43/006—Delaminating
    • 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
    • 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
    • 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

  • the present invention relates generally to films, including both monoiayer films and multilayer films, especially packaging films
  • the present invention also relates to packaged products comprising a product packaged in a film
  • the present invention is particularly related to films having a relatively low film-to-film and film-to-metal coefficient of friction
  • the present invention is directed to a film having an outer layer comprising a vinyl polymer having grafted fatty amide thereon
  • the grafted fatty amide comprises at least one member selected from the group consisting of grafted primary fatty amide, grafted secondary fatty amide, and grafted tertiary fatty amide, more preferably, at least one member selected from the group consisting of grafted erucamide, grafted oleamide, grafted linoleamide, and grafted linolenamide, still more preferably, at least one member selected from the group consisting of grafted erucamide and grafted oleamide
  • the film can be a monoiayer film or a multilayer film
  • the film is a multilayer film
  • One preferred film in accordance with the present invention is a heat-shrinkable film comprising (a) a first outer layer which serves as a seal layer, (b) a first inner layer comprising an ethylene/alpha-olefin copolymer having a density of from about 0 89 to 0 915, (c) a second inner layer comprising at least one member selected from the group consisting of polyvinylidene chloride, ethylene/vinyl alcohol copolymer, poiyamide, polyester, polyethylene carbonate, and polyacrylonitrile, (d) a third inner layer comprising an ethylene/alpha-olefin copolymer having a density of from about 0 89 to 0 915, and (e) a second outer layer which serves as an abuse layer
  • the first inner layer is between the first outer layer and the second inner layer
  • the second inner layer is between the first
  • Another preferred multilayer film comprises outer layers comprising ethylene/vinyl acetate copolymer, an inner layer comprising polyvinylidene chloride, and an inner layer comprising linear low density polyethylene (preferably a blend of 85 weight percent linear low density polyethylene and 15 weight percent ethylene/vinyl acetate copolymer)
  • Another preferred multilayer film is a biaxially-oriented, heat-shrinkable film comprising
  • the multilayer film has a free shrink, at 185°F, of at least 80 percent, and all layers of the multilayer film are shrink-compatible with respect to one another
  • Another preferred multilayer film comprises a first layer having been subjected to an energetic radiation surface treatment in a dosage of up to about 12 MR, said first layer comprising poiyamide
  • the first layer serves as a food-contact and food- adhesion layer
  • Another multilayer film has low oxygen permeability and comprises, (a) first and second layers, at least one of which comprises an olefin polymer crosslinked from exposure irradiation at a level of from about 2 to 12 MR; and, (b) a third layer which is between the first and second layers, the third layer comprising hydrolyzed ethylene/vinyl acetate copolymer, the multilayer film having a level of heat shrinkage, at 195°F, of at least 10 percent in a longitudinal direction and at least 10 percent in a transverse direction
  • Another multilayer film is a hot-blown film comprising: (a) a first layer, the first layer being an outer layer, the first layer comprising at least one member selected from the group consisting of linear low density polyethylene
  • Another preferred multilayer film is a hot-blown film comprising (a) a first layer, the first layer being an outer layer, the first layer comprising at least one member selected from the group consisting of ethylene/alpha-olefin copolymer, fractional melt index low density polyethylene, and ethylene/ester copolymer; (b) a second layer which is adhered to the first layer, the second layer being an inner layer, the second layer containing an abuse- resistant polymer comprising at least one member selected from the group consisting of very low density polyethylene, ethylene/vinyl acetate copolymer having a fractional melt index, and ionomer; (c) a third layer, the third layer being a second inner layer, the third layer comprising chemically-modified polyolefinic adhesive; (d) a fourth layer, the fourth layer being a third inner layer, the fourth layer comprising at least one member selected from the group consisting of poiyamide 6 and copolyamide, (e) a fifth layer adhered to the
  • Another preferred multilayer film comprises (a) a first outer layer comprising (i) a polymeric component comprising at least one member selected from the group consisting of ethylene homopolymer, ethylene/alpha-olefin copolymer, ethylene/ester copolymer, ethylene/acid copolymer, and ionomer, and (ii) a surface-active agent component comprising at least one member selected from the group consisting of ester of aliphatic alcohol, polyether, polyhydric alcohol, ester of polyhydric aliphatic alcohol, and polyethoxylated aromatic alcohol, (b) at least one inner layer comprising polyolefin, and (c) a second outer layer comprising at least one member selected from the group consisting of ethylene homopolymer, ethylene/alpha-olefin copolymer, ethylene/ester copolymer, ethylene/acid copolymer, and ionomer
  • the surface-active component is present over the entire outside surface ofthe first outer
  • thermoformable film comprising (a) a first layer which is a core layer which comprises an O 2 -barrier composition, (b) a second layer and a third layer, each of which is directly adhered to a surface of the first layer, each of the second layer and the third layer comprising poiyamide and a nucleating agent, (c) a fourth layer which is a first outer layer and which serves as a sealing layer, and (d) a firth layer which is a second outer layer and which comprises a moisture barrier composition
  • Another preferred multilayer film is a coextruded, tubular, and laminated, and is suitable for use in elevated temperature media, comprising (a) a first layer comprising a film-forming poiyamide, (b) a second layer comprising an alpha-olefin polymer or copolymer, and, (c) an adhesive between the first and second layers, the adhesive comprising alpha-olefin mer units as a major component thereof
  • the adhesive and the alpha-olefin polymer or copolymer are each crosslinked by irradiation at a dosage level of at least about 6 MR
  • Another preferred multilayer film is an oriented, heat-shrinkable film comprising
  • a first layer which is a cross-linked inner layer comprising a blend comprising ethylene/vinyl alcohol copolymer and poiyamide, the first layer having a thickness of from about 5 to 25 percent of a total thickness of the multilayer film
  • a second layer and a third layer each of which is an inner film layer, each of which comprises a crosslinked polymer, and each of which comprises an adhesive resin
  • a fourth layer and a fifth layer each of which is an outer film layer, each of which comprises a three-component blend of linear low density polyethylene, linear medium density polyethylene, and ethylene/vinyl acetate copolymer
  • the total thickness of the multilayer film is from about
  • Another preferred multilayer film is an oriented, heat-sealable film comprising (a) first and second layers each of which are outer layers comprising a biend comprising linear low density polyethylene, linear medium density polyethylene, and, ethylene/vinyl acetate copolymer, and (b) a third layer which is an inner layer comp ⁇ sing a crosslinked polymer consisting essentially of linear low density polyethylene
  • Another preferred multilayer film is an oriented film comp ⁇ sing (a) first and second layers each of which is an outer layer comprising linear low density polyethylene, linear medium density polyethylene, and, ethylene/vinyl acetate copolymer, and (b) a third layer which is an inner layer comprising a member selected from the group consisting of (i) ethylene/vinyl acetate copolymer, and (11) in combination, linear low density polyethylene, linear medium density polyethylene, and ethylene/vinyl acetate, and, (c) fourth and fifth layers each of which is an inner layer comprising linear low density polyethylene, and wherein the third layer is between the fourth and fifth layers
  • Another preferred multilayer film is a heat-shrinkable film comprising (a) first and second layers each of which is an outer layer, and (b) a third layer which is an inner layer comprising a member selected from the group consisting of (1) ethylene homopolymer, ethylene copolymer, and ethylene terpolymer, and (11) a blend of ethylene homopolymer or ethylene copolymer with butylene homopolymer or butylene copolymer At least one layer of the multilayer film is stretch-oriented and comp ⁇ ses at least one member selected from the group consisting of polyester and copolyester
  • Another preferred multilayer film is a heat-shrinkable comp ⁇ sing (a) first and second layers each of which is an outer layer, and (b) a third layer which is an inner layer comprising from 70 to 90 weight percent, based on layer weight, of at least one member selected from the group consisting of ethylene homopolymer and ethylene copolymer, butylene homopolymer, and butylene copolymer, wherein from about 10 to 30 weight percent of the third layer is selected from the group consisting of butylene homopolymer and butylene copolymer At least one film layer comp ⁇ ses at least one member selected from the group consisting of propylene homopolymer and propylene copolymer
  • Another preferred multilayer film comprises (a) first and second layers each of which is an outer layer comprising ethylene propylene copolymer in an amount of from about 70 to 90 weight percent, based on layer weight, and propylene homopolymer in an amount of from about 10 to 30 weight percent, based on layer weight, and (b) a third layer which is an inner iayer comp ⁇ sing at least one member selected from the group consisting of linear low density polyethylene and linear medium density polyethylene.
  • the multilayer film has an average machine direction free shrink at 200°F of at least 12% and an average transverse direction free shrink at 200°F of at least about 17%
  • Another preferred multilayer film comprises: (a) a first layer consisting essentially of a crosslinked ethylene/vinyl acetate copolymer; (b) a second layer comprising an 02- barrier material comprising vinyl chloride-vinylidene chloride copolymer; and (c) a third layer comprising a non-crosslinked ethylene/vinyl acetate copolymer
  • Another preferred multilayer film comprises: (a) an inner layer comprising homogeneous ethylene/alpha-olefin copolymer having a density of from about 0 89 to 0.92 grams per cubic centimeter; (b) a first outer layer comprising at least one member selected from the group consisting of propylene homopolymer, propylene copolymer, a blend of homopolymer or copolymer of polypropylene and elastomer, high density polyethylene, and copolyester; and (c) a second outer layer comprising at least one member selected from the group consisting of poiyamide, copolyamide, polyester, copolyester, high density polyethylene, polypropylene, propylene/ethylene copolymer, and polycarbonate.
  • Another preferred multilayer film comprises: (a) a first layer comprising a blend of elastomer and at least one member selected from the group consisting of propylene homopolymer and propylene copolymer; and (b) a second layer in adherence with the first layer, the second layer comprising an ethylene/alpha-olefin copolymer having a density of less than or equal to 0.89 grams per cubic centimeter
  • Another preferred multilayer film comprises: (a) a first layer comprising at least one member selected from the group consisting of ethylene/vinyl acetate copolymer and linear low density polyethylene, wherein the first layer is an inner Iayer; (b) second and third layers directly adhered to the first layer, both the second Iayer and the third Iayer being inner layers, and both the second and third layers consisting essentially of a linear low density polyethylene; and (c) fourth and fifth layers, each of which is an outer film Iayer, each of which consists essentially of ethylene/vinyl acetate copolymer
  • the multilayer film has a shrink tension, at 205°F, of at least about 450 psi in a transverse direction, and at least about 450 psi in a longitudinal direction, and wherein the multilayer film has an elongation to break, at 73°F, of at least about 200% in the transverse direction and at least about 200% in the longitudinal direction
  • Another preferred multilayer film is a coextruded film comprising (a) a first layer which is an inner layer comprising ethylene/vinyl alcohol copolymer, (b) a second Iayer and a third layer, each of which are inner layers comprising poiyamide, (c) a fourth layer and a fifth layer, each of which are inner layers comprising an adhesive polymer, and (d) a sixth layer and a seventh layer, each of which are outer layers comprising a blend of linear low density polyethylene and an anti-blocking agent, the linear low density polyethylene being present in an amount of from about 85 to 99 percent, based on layer weight, and the anti-blocking agent being present in an amount of from about 1 to 15 percent, based on Iayer weight
  • the first layer is between the second Iayer and the third layer, and the first, second, and third layers are between the fourth layer and the fifth layer
  • Another preferred multilayer film comprises (a) a first layer and a second layer, both of which are outer layers containing a polymer comprising at least one member selected from the group consisting of (i) olefin, and (ii) polyester, and (b) a third layer which is an inner layer and which comprises polyolefin
  • the third Iayer is between the first layer and the second layer and the film has a maximum average machine direction shrink tension of no more than about 300 psi, and a maximum average transverse direction shrink tension of no more than about 300 psi, said shrink tension values being measured under ASTM D 2838, and the polymer in the first and second layers comprises polymer having a melting point at least about 10°C higher than a melting point of the polyolefin in the third Iayer
  • Another preferred multilayer film comprises (a) a first Iayer and a second layer, both of which are outer layers containing a polymer comprising at least one member selected from the group consisting of linear low density polyethylene, and ethylene/propylene copolymer, (b) a third layer which is an inner layer and which comprises at least one member selected from the group consisting of linear low density polyethylene, and ethylene/propylene copolymer, and (c) a fourth layer and a fifth layer, each of which comprises a polymer having a melting point of less than about 100°C
  • the film has an average machine direction shrink tension at 205°F of no more than about 250 psi, and an average transverse direction shrink tension at 205°F of no more than about 300 psi, said shrink tension values being measured under ASTM D 2838
  • gas-permeable film which can be manually delaminated from a gas impermeable film
  • the gas-permeable film comprises (i) a first layer which serves as a heat-sealable layer and which comprises at least one member selected from the group consisting of ethylene homopolymer and ethylene copolymer; and (ii) a second layer which comprises linear ethylene/alpha-olefin copolymer having a density of less than about 0 915 g/cc
  • the gas-impermeable film comprises (i) a first layer which comprises at least one member selected from the group consisting of ethylene/vinyl alcohol copolymer, vinylidene chloride copolymer, and vinylidene chloride terpolymer, this first Iayer being directly to the second layer ofthe gas-permeable film in a manner so that when delamination occurs the barrier layer becomes a first surface layer, and (ii) a second layer comprising a polymer,
  • Another preferred multilayer film is a film which is suitable for use in vacuum skin packaging, comprising (a) a first layer which is a bonding Iayer comprising at least one member selected from the group consisting of low density polyethylene, high density polyethylene, and ionomer, (b) a second layer which is a complementary layer comprising an ethylene/vinyl acetate copolymer comprising vinyl acetate mer in an amount of from about 15 to 25 percent, based on copolymer weight, the remainder of the copolymer comprising ethylene mer, wherein the copolymer is crosslinked, the second layer having a thickness of from about 16 to 225 microns, and (c) a third Iayer which is an outer layer which is coextruded with the first layer, the second layer being between the first layer and the third layer, the third layer comprising at least one member selected from the group consisting of low density polyethylene, high density polyethylene, linear low density polyethylene, ionomer, and ethylene vinyl acetate cop
  • Another preferred multilayer film is a heat-shrinkable film comp ⁇ sing a homogeneous single-site catalyzed copolymer of ethyiene and an alpha-olefin having from three to ten carbon atoms, said copolymer having a density of at least about 0 90 g/cc, wherein the film has an outer surface comprising a vinyl polymer having grafted fatt ⁇ amide thereon
  • Another preferred multilayer film is a heat-shrinkable and has a substantially symmet ⁇ cal structure comprising (a) outer layers comprising at least one member selected from the group consisting of propylene homopolymer and propylene copolymer, and (b) an inner layer comp ⁇ sing a homogeneous smgle-site-catalyzed copolymer of ethylene and an alpha-olefin having from four to eight carbon atoms
  • Another preferred multilayer film is a heat-shrinkable film comprising (a) a first layer which is an outer layer and which serves as a heat sealing Iayer, (b) a second layer which is an inner layer and which comprises a homogeneous single-site-catalyzed copolymer of ethylene and an alpha-olefin having from three to ten carbon atoms, the copolymer having a density of at least about 0 90 g/cc, and (c) a third layer which is an O 2 -bar ⁇ er layer
  • Another preferred multilayer film is a heat-shrinkable film comprising (a) a first layer which is an outer layer and which serves as a heat sealing layer comprising a homogeneous single-site-catalyzed copolymer of ethylene and an alpha-olefin having from three to eight carbon atoms, the copolymer having a density of at least about 0 90 g/cc, and (b) a second layer which is
  • Another preferred multilayer film is a heat-shrinkable film having a substantially symmetrical structure and comprising (a) first and second outer layers comprising a homogeneous single-site-catalyzed copolymer of ethylene and an alpha-olefin having from three to eight carbon atoms, the copolymer having a density of at least about 0 90 g/cc,
  • the film is a heat-shrinkable film having an impact strength of at least 35 pounds, per mil of homogeneous polymer More preferably, the film has an impact strength of from about 35 to 90 pounds, per mil of homogeneous polymer, still more preferably, from about 35 to 65 pounds, per mil of homogeneous polymer, yet still more preferably, from about 60 to 90 pounds, per mil of homogeneous polymer
  • the film is a multilayer film, and the homogeneous polymer is present in a core layer
  • the homogeneous polymer is present in a film Iayer in an amount of about 100 percent, based on the weight ofthe film Iayer, the film layer having a thickness of about 1 mil
  • the multilayer film further comprises an outer sealant layer and a barrier layer
  • the multilayer film further comprises an outer abuse layer
  • the multilayer film further comprises at least one tie Iayer, more preferably, the multilayer film comprises a first tie layer between the barrier layer and the
  • the film is a heat-shrinkable film comprising homogeneous ethyl ene/alpha- olefin copolymer, the film having an impact strength of from about 35 to 200 pounds and a total free shrink, at 185°F, of from about 80 to 150 percent; more preferably, the film has an impact strength of from about 40 to 90 pounds, still more preferably, the heat- shrinkable film has a total free shrink at 185°F, of from about 80 to 120 percent
  • the heat-shrinkable film has a total thickness of from about 1 to 3 mils .
  • another preferred film is a monoiayer or multilayer film comprising homogeneous ethylene/alpha-olefin copolymer, more preferably in an inner layer of a multilayer film
  • the homogeneous ethylene/alpha-olefin copolymer is present in the inner layer in an amount of from about 60 to 100 weight percent, based on the weight of the inner Iayer
  • the homogeneous ethylene/alpha olefin copolymer is a first component present in a composition which further comp ⁇ ses a second component comprising least one member selected from the group consisting of another ethylene/alpha-olefin copolymer, ethylene/vinyl acetate copolymer, ethylene/vinyl ester copolymer, ethylene/acrylic acid copolymer, propylene/ethylene copolymer, polyethylene homopolymer, polypropylene homopolymer, and ionomer, wherein the second component is present in the composition in an amount of from about 1 to 40 weight percent, based on the weight of the composition
  • the first component and the second component are in a substantially uniform blend
  • the homogeneous ethylene/alpha olefin copolymer is present in a composition which further comprises at least one member selected from the group consisting of a maleic anhydride grafted ethylene/alpha-olefin copo
  • the first inner layer is a first tie layer
  • the second inner layer is an O 2 -bar ⁇ er Iayer
  • the third inner Iayer is a second tie layer
  • the first and second outer layers are substantially identical in chemical composition and thickness
  • the first and second tie layers are substantially identical in chemical composition and thickness, with the heat-shrinkable film being substantially symmetrical
  • Another preferred multilayer film is a heat-shnnkable film comp ⁇ sing homogeneous ethylene/alpha-olefin copolymer, the heat-shnnkable film having an impact strength of from about 80 to 250 pounds and a total free shrink, at 185°F, of from about 30 to 150 percent
  • the heat-shrinkable film has an impact strength of from about 80 to 200 pounds, and a total free shrink, at 185°F, of from about 50 to 120 percent
  • the heat-shnnkable film is a monoiayer film or a multilayer film
  • the heat-shnnkable film is a multilayer heat-shrinkable film
  • the Iayer comp ⁇ sing the homogeneous ethylene/alpha olefin copolymer is an inner layer
  • Another preferred multilayer film comprises a homogeneous single site catalyzed copolymer of ethylene and an alpha-olefin having from three to ten carbon atoms, wherein the single site catalyzed copolymer has long chain branching
  • Another preferred multilayer film comprises a homogeneous single site catalyzed copolymer of ethylene and an alpha-olefin having from three to ten carbon atoms, said single site catalyzed copolymer having limited long chain branching
  • Another preferred multilayer film is a heat-shrinkable film comprising a single-site- catalyzed ethylene/alpha olefin copolymer wherein the alpha-olefin has from four to eight carbon atoms
  • the single-site-catalyzed copolymer is blended with another thermoplastic homopolymer or copolymer
  • the single site catalyzed copolymer has a density of from about 0.86 to 0 95 g/cc
  • the film is a multilayer film
  • Another preferred multilayer film is a heat-shrinkable film comprising at least one inner core Iayer comprising a homogeneous single site catalyzed copolymer of ethylene and an alpha
  • Another preferred multilayer film is a heat-shrinkable film comprising the general structure seal/corc/barrier/core/abuse, wherein each of the core layers comprises the same homogeneous long chain branched single-site catalyzed copolymer of ethylene and an alpha- olefin having from four to ten carbon atoms, said copolymer having a density of from about 0 89 g/cc to about 0 91 g/cc
  • Another preferred multilayer film is a heat-shrinkable film comprising (a) a seal layer, (b) a first inner iayer comprising a homogeneous, long chain branched ethylene/alpha- olefin copolymer having a density of from about 0 89 to 0 91 g/cc, (c) an O 2 -barrier Iayer, (d) a second inner layer comprising a homogeneous, long chain branched ethylene/alpha-olefin copolymer having a density of from about 0 89 to 0 91 g/cc, and (e) an abuse layer, wherein the homogeneous, long chain branched ethylene/alpha-olefin copolymer in the first inner layer differs from the homogeneous, long chain branched ethylene/alpha-olefin copolymer in the second inner layer
  • Another preferred multilayer film is a heat-shrinkable film comprising (a) a sealing layer comprising a homogeneous, single-site-catalyzed copolymer of ethylene and an alpha-olefin having from four to ten carbon atoms, the copolymer having long chain branching and a density of from about 0.89 g/cc to about 0 91 g/cc, (b) an 0 2 -barrier layer, (c) an abuse layer comprising a second inner layer comprising a homogeneous, long chain branched ethylene/alpha-olefin copolymer having a density of from about 0.89 to 0 91 g/cc, and (d) an abuse layer comprising a homogeneous, single-site-catalyzed copolymer of ethylene and an alpha-olefin having from four to ten carbon atoms, the copolymer having long chain branching and a density of from about 0 89 g
  • Another preferred multilayer film is a heat-shrinkable film comprising the general structure seal/core/barrier/core/abuse, wherein each ofthe two core layers comprises the same homogeneous copolymer of ethylene and octene having an I ⁇ r/1 2 gr-eater than or equal to 5 63 and a M.JM reside less than or equal to (InJl 2 ) - 4.63, said copolymer having a density of from about 0 89 g/cc to about 091 g/cc
  • Another preferred multilayer film is a heat-shrinkable film comprising (a) a sealing Iayer, (b) a first inner layer comprising a homogeneous ethylene octene copolymer having an I ⁇ o/I greater than or equal to 5 63 and a M w /M ⁇ less than or equal to (Im/I 2 ) - 4 63, said copolymer having a density of from about 0 89 g/cc to about 0 91 g/cc, (c) an O 2 -barrier layer, (d) a second inner layer comprising a homogeneous ethylene octene copolymer having an I ) I 2 greater than or equal to 5 63 and a M M n less than or equal to (l ⁇ o/I ) - 4 63, said copolymer having a density of from about 0 89 g/cc to about 0 1 g/cc, and (E) an abuse layer
  • the present invention is directed to an article comprising a heat- shrinkable multilayer film comprising a film layer comprising homogeneous ethylene/alpha- olefin copolymer, wherein the heat-shrinkable film has an impact strength of from about 35 to 200 pounds and a total free shrink, at 185°F, of from about 80 to 150 percent, and wherein the article is a member selected from the group consisting of a bag and a casing, and wherein the film has an outer layer comprising a vinyl poly
  • the present invention is directed to a method of making a film having an outer surface comprising grafted fatty amide, comprising (A) preparing a vinyl polymer having a grafted fatty amide thereon, by (i) mixing a vinyl polymer with a peroxyketal initiator and an unsaturated fatty amide, and (ii) reacting the vinyl polymer with the unsaturated fatty amide in the presence of the peroxyketal initiator The reacting is carried out in a batch reactor comprising a mixer that is capable of generating high shear to achieve a homogeneous melt, so that a vinyl polymer having a grafted fatty amide is produced, (B) extruding the vinyl polymer having grafted fatty amide to form a film, wherein the extrusion is carried out so that the vinyl polymer having the grafted fatty amide is present on an outer film surface
  • the mixer comprises at least one member selected from the group consisting of a corotating twin screw
  • films of and used in the present invention have a thickness of 0 25 mm or less
  • packaging refers to packaging materials configured around a product being packaged
  • packaged product refers to the combination of a product which is su ⁇ ounded by a packaging material.
  • the term "seal" refers to any seal of a first region of a film surface to a second region of a film surface, wherein the seal is formed by heating the regions to at least their respective seal initiation temperatures.
  • the sealing can be performed by .any one or more of a wide variety of manners, such as using a heated bar, hot air, hot wire, infrared radiation, ultrasonic sealing, radio frequency sealing, etc.
  • the preferred sealing mechanism is a seal made on a bag machine using a hot-wire.
  • the film preferably has a film-to-film coefficient of friction of from about 0 I to 0.9, more preferably the film has a film-to-film coefficient of friction of from about 0.1 to 0.7, still more preferably, from about 0.1-0.6, and yet still more preferably, from about 0.1 to 0.5.
  • Fatty amides useful in the present invention are disclosed in A L Mc enna, Fatty Amides, c.1982, Witco Chemical Corporation, which is hereby incorporated, in its entirety, by reference thereto.
  • the phrases “food-contact layer” and “meat-contact layer” refer to a layer of a multilayer film which is in direct contact with the food/meat in the package comprising the film
  • a food-contact layer is always an outer film layer, as the food-contact layer is in direct contact with the food product within the package
  • the food- contact layer is an inside layer in the sense that with respect to the packaged food product, the food-contact layer is the inside layer (i.e., innermost Iayer) of the package, this inside layer being in direct contact with the food.
  • the phrases “food-contact surface” and “meat-contact surface” refer to an outer surface of a food contact layer, this outer surface being in direct contact with the food within the package
  • the phrase “cook-in” refers to the process of cooking a product packaged in a material capable of withstanding exposure to long and slow cooking conditions while containing the food product, for example submersion in water at 57°C to 121 °C (i.e, 135°F-250°F) for 2-12 hours, preferably 57°C to 100°C (i.e, 135°F-250°F) for 2-12 hours.
  • Cook-in packaged foods are essentially pre-packaged, pre-cooked foods which may be directly transferred to the consumer in this form These types of foods may be consumed with or without warming.
  • Cook-in packaging materials maintain seal integrity, and in the case of multilayer films are delamination resistant Cook-in films must also be heat sh ⁇ nkable under cook-in conditions so as to form a tightly fitting package
  • Cook-in films preferably have a tendency for adhesion to the food product, thereby preventing "cook-out", which is the collection of juices between the outer surface ofthe food product and the meat-contact surface ofthe film, i e , the surface in direct contact with the meat
  • Additional optional charactenstics of films for use in cook-in applications include delamination-resistance, low O 2 -permeab ⁇ l ⁇ ty, heat-sh ⁇ nkabihty representing about 20-50% biaxial sh ⁇ nkage at about 85°C (185°F), and optical clanty
  • the external surface of the package is preferred that
  • barner As used herein, the term “barner”, and the phrase “banner layer”, as applied to films and/or film layers, are used with reference to the ability of a film or film layer to serve as a barner to one or more gases
  • oxygen (i e gaseous O 2 ) barner layers have included, for example, hydrolyzed ethylene/vinyl acetate copolymer (designated by the abbreviations “EVOH” and “HEVA” and also referred to as “ethylene/vinyl alcohol copolymer”), polyvinylidene chlo ⁇ de, poiyamide, polyester, polyacrylonitrile, etc as known to those of skill m the art
  • the phrase "abuse layer” as well as the phrase “puncture-resistant layer”, refer to an outer film layer and/or an inner film layer so long as the film Iayer serves to resist abrasion, puncture, and other potential causes of reduction of package integnty, as well as potential causes of reduction of package appearance quality
  • laminate As used herein, the terms “lamination,” “laminate,” as well as the phrase “laminated film,” refer to the process, and resulting product, made by bonding together two or more layers of film or other mate ⁇ als Lamination can be accomplished by loining layers with adhesives, joining with heat and pressure, with corona treatment, and even spread coating and extrusion coating
  • laminate is also inclusive of coextruded multilayer films compnsing one or more tie layers
  • the term "o ⁇ ented” refers to a polymer-containing mate ⁇ al which has been elongated (generally at an elevated temperature called the o ⁇ entation temperature) followed by being “set” in the elongated configuration by cooling the matenal while substantially retaining the elongated dimensions
  • This combination of elongation at elevated temperature followed by cooling causes an alignment of the polymer chains to a more parallel configuration, thereby improving the mechanical properties of the film
  • heat shrinkage is produced almost to the original dimensions, i e., pre- elongation dimensions
  • oriented is herein used with reference to oriented films, which can undergo orientation in any one or more of a variety of manners.
  • the term “comonomer” refers to a monomer which is copolymerized with at least one different monomer in a copolymerization reaction, the result of which is a copolymer
  • the term “polymer” refers to the product of a polyme ⁇ zation reaction, and is inclusive of homopolymers, copolymers, te ⁇ olymers, tetrapolymers, etc
  • the layers of a film can consist essentially of a single polymer, or can have additional polymers together therewith, 1 e , blended therewith
  • the term “homopolymer” is used with reference to a polymer resulting from the polyme ⁇ zation of a single monomer, I e , a polymer consisting essentially of a single type of repeating unit
  • the term "copolymer” refers to polymers formed by the polyme ⁇ zation reaction of at least two different monomers
  • the term “copolymer” includes the copolyme ⁇ zation reaction product of ethylene and an alpha-olefin, such as 1 -hexene
  • the term “copolymer” is also inclusive of, for example, the copolymenzation of a mixture of ethylene, propylene, 1 -hexene, and 1 -octene
  • the term “copolymenzation” refers to the simultaneous polyme ⁇ zation of two or more monomers
  • copolymer is also inclusive of random copolymers, block copolymers, and graft copolymers
  • the term “polymenzation” is inclusive of homopolymenzations, copolymenzations, te ⁇ olymenzations etc , and includes all types of copolyme ⁇ zations such as random, graft,
  • a copolymer identified in terms of a plurality of monomers refers to a copolymer in which either monomer may copolymenze in a higher weight or molar percent than the other monomer or monomers
  • the first listed monomer preferably polymenzes in a higher weight percent than the second listed monomer
  • copolymers which are te ⁇ olymers quad ⁇ polymers, etc preferably the first monomer copolymenzes in a higher weight percent than the second monomer, and the second monomer copolymenzes in a higher weight percent than the third monomer, etc
  • copolymers are identified, i e, named, in terms of the monomers from which the copolymers are produced
  • the phrase "propylene/ethylene copolymer” refers to a copolymer produced by the copolymerization of both propylene and ethylene, with or without additional comonomer(s)
  • the phrase "mer” refers to a unit of a polymer, as derived from a monomer used in the polymerization reaction
  • alpha-olefin mer refers to a unit in, for example, an ethylene/alpha-olefin copolymer, the polymerization unit being that "residue" which is derived from the alpha-olefin monomer after it reacts to become a portion of the polymer chain, i e , that portion of the polymer contributed by an individual alpha-olefin monomer after it reacts to become a portion of the polymer chain
  • EVOH refers to ethylene vinyl alcohol copolymer EVOH includes saponified or hydrolyzed ethylene vinyl acetate copolymers, and refers to a vinyl alcohol copolymer having an ethylene comonomer, and prepared by, for example, hydrolysis of vinyl acetate copolymers, or by chemical reactions with polyvinyl alcohol The degree of hydrolysis is preferably from about 50 to 100 mole percent, more preferably, from about 85 to 100 mole percent
  • the vinyl polymer comprises at least one member selected from the group consisting of ethylene mer, propylene mer, alpha-olefin mer, aromatic mer, anhydride mer, ester mer, acid mer, and amide mer. More preferably, the vinyl resin comprises at least one member selected from the group consisting of ethylene mer, alpha- olefin mer, aromatic mer, anhydride mer, ester mer, and acid mer, more preferably, at least one member selected from the group consisting of ethylene mer and alpha-olefin mer
  • the fatty amide is grafted to the vinyl polymer by reacting the fatty amide with unsaturated sites on the vinyl polymer If the vinyl polymer has no unsaturated sites thereon, the vinyl polymer can be reacted with a peroxide, in order to form unsaturated sites which are reactive with the fatty amide, to result in a grafted fatty amide vinyl polymer
  • the temperature and pressure within an extruder is appropriate for carrying out both the reaction o( the peroxide with the vinyl polymer, as well as for carrying out the reaction ofthe unsaturated sites ofthe vinyl polymer with the fatty amide.
  • heteropolymer refers to polymerization reaction products of relatively wide variation in molecular weight and relatively wide variation in composition distribution, i e , polymers made, for example, using conventional Ziegler-Natta catalysts Heterogeneous polymers are useful in va ⁇ ous layers of the film used in the present invention Such polymers typically contain a relatively wide variety of chain lengths and comonomer percentages
  • heterogeneous catalyst refers to a catalyst suitable for use in the polymerization of heterogeneous polymers, as defined above Heterogeneous catalysts are comprised of several kinds of active sites which differ in Lewis acidity and steric environment Ziegler-Natta catalysts are heterogeneous catalysts Examples of Ziegler-Natta heterogeneous systems include metal halides activated by an organometallic co-catalyst, such as titanium chloride, optionally containing magnesium chlonde, complexed to trialkyl aluminum .and may be found in patents such as U S Patent No 4,302,565, to GOEKE, et al , and U S.
  • homogeneous polymer refers to polymerization reaction products of relatively nanow molecular weight distribution and relatively narrow composition distribution
  • Homogeneous polymers can be used in various layers of multilayer films useful in the present invention
  • Homogeneous polymers are structurally different from heterogeneous polymers, in that homogeneous polymers exhibit a relatively even sequencing of comonomers within a chain, a mirroring of sequence distribution in all chains, and a similarity of length of all chains, i e , a narrower molecular weight distribution
  • homogeneous polymers are typically prepared using metallocene, or other single-site type catalysis, rather than using Ziegler Natta catalysts
  • homogeneous ethylene/alpha-olefin copolymers may be characterized by one or more methods known to those of skill in the art, such as molecular weight distribution (M-JM n ), composition distribution breadth index (CDBI), narrow melting point range, and single melt point behavior
  • M-JM n molecular weight distribution
  • CDBI composition distribution breadth index
  • the molecular weight distribution (M,JM n ), also known as "polydispersity,” may be determined by gel permeation chromatography
  • Homogeneous ethylene/alpha-olefin copolymers which can be used in the present invention preferably have an M M- of less than 2 7, more preferably from about 1 9 to 2 5, still more preferably, from about 1 9 to 2 3
  • the composition distribution breadth index (CDBI) of such homogeneous ethylene/alpha-olefin copolymers will generally be greater than about 70 percent
  • the CDBI is defined as the weight percent of the copolymer molecules having
  • the homogeneous ethylene/alpha-olefin copolymers have a CDBI greater than about 70%, i e , a CDBI of from about 70% to 99%.
  • the homogeneous ethylene/alpha-olefin copolymers useful in the present invention also exhibit a relatively narrow melting point range, in comparison with "heterogeneous copolymers", i.e., polymers having a CDBI of less than 55%
  • the homogeneous ethylene/alpha-olefin copolymers exhibit an essentially singular melting point characteristic, with a peak melting point (T m ), as determined by Differential Scanning Colorimetry (DSC), of from about 60°C to 105°C
  • the homogeneous copolymer has a DSC peak T m of from about 80°C to 100°C
  • the phrase "essentially single melting point” means that at least about 80%, by weight, of the mate ⁇ al corresponds to a single T m peak at a temperature within the range of from about 60°C to 105°C, and essentially no substantial fraction of the matenal has a peak melting point in excess of about 1 15°C
  • a homogeneous ethylene/alpha-olefin copolymer can, in general, be prepared by the copolymenzation of ethylene and any one or more alpha-olefin
  • the alpha-olefin is a G-C 2 n alpha-monoolefin, more preferably, a C4-C12 alpha-monoolefin, still more preferably, a Ct-Cs alpha-monoolefin
  • the alpha-olefin compnses octene- 1 , and/or a blend of hexene- 1 and butene- 1 Processes for prepan
  • polyolefin refers to any polymenzed olefin, which can be linear, branched, cyclic, aliphatic, aromatic, substituted, or unsubstituted More specifically, included in the term polyolefin are homopolymers of olefin, copolymers of olefin, copolymers of an olefin and an non-olefinic comonomer copolymenzable with the olefin, such as vinyl monomers, modified polymers thereof, and the like Specific examples include polyethylene homopolymer, polypropylene homopolymer, polybutene, ethylene/alpha-olefin copolymer, propylene/alpha-olefin copolymer, butene/alpha-olefin copolymer, ethylene/vinyl acetate copolymer, ethylene/ethyl acrylate copolymer, ethylene/butyl acrylate
  • identifying polymers such as “poiyamide”, “polyester”, “polyurethane”, etc are inclusive of not only polymers comprising repeating units derived from monomers known to polymerize to form a polymer ofthe named type, but are also inclusive of comonomers, derivatives, etc which can copolymenze with monomers known to polymerize to produce the named polymer
  • the term “poiyamide” encompasses both polymers comprising repeating units derived from monomers, such as caprolactam, which polymerize to form a poiyamide, as well as copolymers derived from the copolymerization of caprolactam with a comonomer which when polymerized alone does not result in the formation of a poiyamide
  • terms identifying polymers are also inclusive of "blends" of such polymers with other polymers of a different type
  • anhydride functionality refers to any form of anhydride functionality, such as the anhydride of maleic acid, fumanc acid, etc , whether blended with one or more polymers, grafted onto a polymer, or copolymerized with a polymer, and, in general, is also inclusive of derivatives of such functionalities, such as acids, esters, and metal salts derived therefrom
  • modified polymer refers to such polymers having an anhydride functionality, as defined immediately above, grafted thereon and/or copolymerized therewith and/or blended therewith Preferably, such modified polymers have the anhydride functionality grafted on or polymerized therewith, as opposed to merely blended therewith
  • anhydride-containing polymer refers to one or more of the following (1 ) polymers obtained by copolymerizing an anhydride-containing monomer with a second, different monomer, and (2) anhydride grafted copolymers, and (3) a mixture of a polymer and an anhydride-containing compound.
  • the term "ionomer”, as used herein, refers to a product of an ionic polymerization, i e . a polymer containing interchain ionic bonding
  • the ionomer comprises at least one member selected from the group consisting of a thermoplastic resin based on metal salt of an alkene/acid copolymer, more preferably, a thermoplastic resin based on metal salt of ethylene/acid copolymer, still more preferably, metal salt of ethylene/methacrylic acid copolymer
  • the term "ionomer” also includes ethylene/acrylic acid copolymer and ethylene/acid acrylate te ⁇ olymer
  • ethylene alpha-olefin copolymer and “ethylene/alpha- olefin copolymer” refer to such heterogeneous materials as low density polyethylene (LDPE), medium density polyethylene (MDPE), linear low density polyethylene (LLDPE), and very low and ultra low density polyethylene (VLDPE and ULDPE), as well as to such homogeneous ethylene/alpha olefin copolymers as metallocene-catalyzed EXACT (TM) linear homogeneous ethylene/alpha olefin copolymer resins obtainable from the Exxon Chemical Company, of Baytown, Texas, homogeneous substantially linear ethylene/alpha- olefin copolymers having long chain branching (e g , copolymers known as AFFINITY (TM) resins, and ENGAGE (TM) resins, available from the Dow Chemical Company, of Midland, Michigan), as well as TAFMER (TM) linear homogeneous ethylene/
  • the phrases “inner layer” and “internal layer” refer to any layer, of a multilayer film, having both of its principal surfaces directly adhered to another layer of the film
  • inside layer refers to an outer film Iayer, of a multilayer film packaging a product, which is closest to the product, relative to the other layers of the multilayer film "Inside layer” also is used with reference to the innermost Iayer of a plurality of concentrically arranged layers simultaneously coextruded through an annular die
  • outer layer refers to any film layer of film having less than two of its principal surfaces directly adhered to another layer of the film
  • the phrase is inclusive of monoiayer and multilayer films All multilayer films have two, and only two, outer layers, each of which has a principal surface adhered to only one other layer of the multilayer film In monoiayer films, there is only one Iayer, which, of course, is an outer layer in that neither of its two principal surfaces are adhered to another layer ofthe film
  • outside layer refers to the outer Iayer, of a multilayer film packaging a product, which is furthest from the product relative to the other layers of the multilayer film
  • Outside layer also is used with reference to the outermost layer of a plurality of concentrically arranged layers simultaneously coextruded through an annular die
  • the phrase "directly adhered”, as applied to film layers, is defined as adhesion ofthe subject film layer to the object film layer, without a tie layer, adhesive, or other layer therebetween.
  • the word "between”, as applied to a film layer expressed as being between two other specified layers includes both direct adherence of the subject Iayer between to the two other layers it is between, as well as including a lack of direct adherence to either or both of the two other layers the subject layer is between, i e., one or more additional layers can be imposed between the subject layer and one or more of the layers the subject layer is between
  • the term “core”, and the phrase “core iayei ", as applied to multilayer films refer to any inner film layer which has a p ⁇ mary function other than serving as an adhesive or compatibilizer for adhe ⁇ ng two layers to one another Usually, the core layer or layers provide the multilayer film with a desired level of strength, i e , modulus, and/or
  • the phrases “seal layer,” “sealing layer,” “heat seal layer,” and “sealant layer,” refer to an outer film layer, or layers, involved in the sealing ofthe film to itself, another film layer ofthe same or another film, and or another article which is not a film It should also be recognized that in general, up to the outer 3 mils of a film can be involved in the sealing of the film to itself or another layer With respect to packages having only fin-type seals, as opposed to lap-type seals, the phrase “sealant layer” generally refers to the inside film layer of a package, as well as supporting layers within 3 mils ofthe inside surface ofthe sealant layer the inside layer frequently also serving as a food contact Iayer in the packaging of foods In general, sealant layers employed in the packaging art have included thermoplastic polymers such as polyolefin, poiyamide, polyester, and polyvinyl chlonde
  • Tie Iayer refers to any inner film layer having the pnmary pu ⁇ ose of adhe ⁇ ng two layers to one another Tie layers can comp ⁇ se any polymer having a polar group thereon, or any other polymer which provides sufficient interlayer adhesion to adjacent layers compnsing otherwise nonadhenng polymers
  • skin layer refers to an outside layer of a multilayer film in packaging a product, this skin layer being subject to abuse
  • the phrase "bulk layer” refers to any layer of a film which is present for the pu ⁇ ose of increasing the abuse-resistance, toughness, modulus, etc , of a multilayer film Bulk layers generally comp ⁇ se polymers which are inexpensive relative to other polymers in the film which provide some specific pu ⁇ ose unrelated to abuse-resistance, modulus, etc
  • first layer is generally indicative of the manner in which a multilayer film structure is built up That is, in general, the first layer can be present without any of the additional layers descnbed, or the first and second layers can be present without any ofthe additional layers desc ⁇ bed, etc
  • extrusion is used with reference to the process of forming continuous shapes by forcing a molten plastic mate ⁇ ai through a die, followed by cooling or chemical hardening Immediately p ⁇ or to extrusion through the die, the relatively high- viscosity polyme ⁇ c matenal is fed into a rotating screw of va ⁇ able pitch, 1 e , an extruder, which forces the polyme ⁇ c matenal through the die
  • coextrusion refers to the process by which the outputs of two or more extruders are brought smoothly together in a feed block, to form a multilayer stream that is fed to a die to produce a layered extrudate
  • Coextrusion can be employed in film blowing sheet and flat film extrusion, blow molding, and extrusion coating
  • machine direction refers to a direction “along the length” of the film, I e , in the direction of the film as the film is formed du ⁇ ng extrusion and/or coating
  • transverse direction refers to a direction across the film, pe ⁇ endicuiar to the machine or longitudinal direction
  • free shnnk refers to the percent dimensional change in a
  • the multilayer films useful in the article and process of the present invention has at least 3 layers (preferably from 3 to 20 layers), and preferably has at least 4 layers (more preferably from 4 to 12 layers, still more preferably, from 4 to 1 1 layers, and yet still more preferably, from 6 to 10 layers)
  • the multilayer film can have any further number of additional layers desired, so long as the film provides the desired properties for the particular packaging operation in which the film is used, e g O 2 -barner charactenstics, free shnnk, shnnk tension, optics, modulus, seal strength, etc
  • the multilayer film illustrated in Figure 1 compnses five layers, in Figure 2, six layers, in Figure 3, six layers
  • the multilayer film used in the present invention can have any total thickness desired, so long as the film provides the desired properties for the particular packaging operation in which the film is used
  • the film has a total thickness of less than about 20 mils, more preferably the film has a total thickness of from about 02 to 10 mils, still more preferably from about 0 3 to 5 mils, and yet still more preferably, from about 1 5 to 4 mils
  • the film of the present invention can be irradiated to induce crosshnking In the irradiation process, the film is subjected to an energetic radiation treatment, such as corona discharge, plasma, flame, ultraviolet, X-ray, gamma ray, beta ray, and high energy electron treatment, which induce cross-linking between molecules of the irradiated matenal
  • an energetic radiation treatment such as corona discharge, plasma, flame, ultraviolet, X-ray, gamma ray, beta ray, and high energy electron treatment, which induce cross-linking between molecules of the irradiated maten
  • a suitable radiation dosage of high energy electrons preferably using an electron accelerator, with a dosage level being determined by standard dosimetry methods
  • Other accelerators such as a Van de Graaf generator or resonating transformer may be used
  • the radiation is not limited to electrons from an accelerator since any ionizing radiation may be used
  • the ionizing radiation can be used to crosslink the polymers in the film
  • the film is irradiated at a level of from 2-15 MR (20-150 kGy), more preferably 2- 10 MR (20-100 kGy)
  • the most preferred amount ot radiation is dependent upon the film composition, thickness, etc , and its end use
  • the film ofthe present invention is particularly useful in the production of bags for packaging fresh red meat, smoked and processed meat, pork, cheese, poultry, and the like, as described in e g U S Patent Nos 3,741 ,253 (Brax et al ) 3,891 008 (D'Lntremont), 4,048,428 (Baird), and 4,284,458 (Schirmer), each of which is hereby incorporated, in its entirety, by reference thereto
  • the film can be of a type suitable for use in bags used for cook-in applications, e g , as disclosed in U S Patent No 4 064,296, to Bornstein et al, entitled "HEAT SHRINKABLF MULTI-LAYER FILM OF HYDROLYZED ETHYLENE VINYL ACETATE AND A CROSS-LINKED OLEFIN POLYMER", as well as U S Patent No 4,855, 183, to T T Oberie, entitled "MULTIPLE LAYER, COOK-IN FILM each
  • the film can be used as a shrink film in packaging applications for packaging food and non-food items
  • Films in which the present invention can be beneficially used are described in, e g , U S Patent Nos 4 5 1 ,380 and 4,643 943, both to Schoenberg, both hereby incorporated, in their entirety, by reference thereto
  • the present invention can also be used with films having oxygen, moisture, or odor barrier functionality, as described in, e g , U S Patent No 4,064,296, to Bornstein et al , U S Patent No 4,724, 185 to Shah, U S Patent No 4,839,235 to Shah, and U S Patent No. 5,004,647 also to Shah, each of which is hereby incorporated in its entirety by reference thereto
  • the film of the present invention can also be used as or in connection with films used in patch bags, i.e., a patch bag as described in U S Patent No 4,755,403, to Ferguson, hereby incorporated, in its entirety, by reference thereto
  • the film can also be of a type suitable for use a medical film application, e g , in the film disclosed in U S S N 08/408,667, filed March 22, 1995, in the name of W B MUELLER, entitled “FILMS FOR MEDICAL SOLUTION POUCHES,” the entirety of which hereby incorporated by reference thereto, as well as in U S S N 08/408,668, filed March 22, 1 95, in the name of W B Mueller, entitled “MULTILAYER FILMS FOR PACKAGING AND ADMINISTERING MEDICAL SOLUTIONS,” the entirety of which is also hereby incorporated by reference thereto
  • the film can also be of a type suitable for use in a thermoformed package, e.g , as disclosed in U S Patent No 4,735,855, to Wofford et al , entitled “THERMOFORMABLE LAMINATE,” the entirety of which is also hereby incorporated by reference thereto
  • the film can also be of the stretch/shrink type, e g , as disclosed in U S Patent
  • the film can also be of a type suitable for the packaging of high acid food products, e.g., as disclosed in US Patent No 4,746,562, to E M Fant, entitled “PACKAGING FILM,” the entirety of which is also hereby incorporated by reference thereto
  • the film can also be of a type suitable for the packaging, water cooking, and storing food within the package, e.g., as disclosed in U S Patent No 4,104,404, to Anne C. Bieler et al., entitled "CROSS-LINKED AMIDE/OLEFIN POLYMERIC TUBULAR FILM COEXTRUDED LAMINATES,” the entirety of which is also hereby incorporated by reference thereto
  • the film can also be a hot blown film of a type useful in chub packaging, e g , as disclosed in U S Patent No 4,937,1 12, to H G Schirmer, entitled “HIGH STRENGTH COEXTRUDED FILM FOR CHUB PACKAGING,” as well as U S Patent No 4,909,726, to S Bekele, entitled “IMPACT-RESISTANT FILM FOR CHUB PACKAGING,” the entirety each of which is hereby incorporated by reference thereto
  • the film can also be of a type having improved physical characteristics through the use of linear low density polyethylene or linear medium density polyethylene resin in a core and/or an intermediate layer, e g , as disclosed in U S Patent No 4,532, 1 9 to W B Mueller, entitled “LiNEAR POLYETHYLENE SHRINK FILMS,” U S Patent No 4, 194,039 to W B Mueller, entitled “MULTI-LAYER POLYOLEFIN SHRINK FILM,” U S Patent No 4,390,385 to D J Ferguson et al, entitled “HEAT-SEALABLE, MULTIPLY POLYPROPYLENE FILM,” U S Patent No 4,274,900 to W B Mueller et al.
  • the film can also be a low shrink energy film, e g , as disclosed in U S Patent No
  • the film can also be of a type suitable for use in vacuum skin packaging, e g , as disclosed in U S Patent No 4,886,690, to K A Davis et al, entitled “PEELABLE BARRIER FILM FOR VACUUM SKIN PACKAGES AND THE LIKE,” as well as U S Patent No 4,963,427, to Botto et al, entitled “MULTILAYER PACKAGING FILM,” U S Patent No 5,075,143, to Bekele, entitled “HIGH BARRIER IMPLOSION RESISTANT FILMS,” the entirety each of which is hereby incorporated by reference thereto
  • the film can also be of a type suitable for use in films comprising homogeneous polymer, e g , as disclosed in U S S N 07/976, 122, to R Babrowicz et al, entitled “HEAT SHRINKABLE FILMS CONTAINING SINGLE SITE CATALYZED COPOLYMERS,” U S S N 08/018,657, to K
  • the film can be used as or in connection with irradiated, oriented, heat set films Additionally, the film of the invention can be laminated, adhesively adhered, extrusion coated, or extrusion laminated onto a substrate to form a laminate
  • Example Low density polyethylene (about 99 8 percent by weight) is mixed with both ethyl 3,3- Di(t-amylperoxy)butyrate (0 05 percent by weight) and erucamide (0 2 percent by weight) in a twin screw extruder
  • the various components reach a temperature of about 360°F, for a time of from about 30 seconds to 5 minutes, du ⁇ ng which the components are mixed to substantial homogeneity while being subjected to the high degree of shear imposed by the twin screw extruder
  • the erucamide is grafted onto the low density polyethylene and thereafter extruded through a die so that a monoiayer film is formed
  • the resulting monoiayer film has a coefficient of friction of about 0 25 per ASTM D 1894, which is hereby inco ⁇ orated in its entirety, by reference thereto

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  • Laminated Bodies (AREA)

Abstract

L'invention concerne un film comprenant une surface extérieure constituée de polymère vinylique à amide gras greffé. Ledit amide gras greffé ne migre pas dans le film et est présent sur la surface du film immédiatement après la formation de celui-ci. Il ne doit pas produire d'efflorescence à la surface du film pour être efficace en tant qu'agent glissant. Il peut être greffé à un polymère par l'addition de celui-ci et d'un peroxyde dans l'extrudeuse, avec une chaleur et une pression dans cette dernière suffisantes pour produire un environnement propice à une réaction de greffage au polymère en fusion en cours d'extrusion.
PCT/US1997/013551 1996-08-02 1997-07-31 Film a amide gras greffe dans sa couche externe WO1998005706A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU39039/97A AU3903997A (en) 1996-08-02 1997-07-31 Film having grafted fatty amide in outerfilm layer

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US2297096P 1996-08-02 1996-08-02
US60/022,970 1996-08-02

Publications (1)

Publication Number Publication Date
WO1998005706A1 true WO1998005706A1 (fr) 1998-02-12

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WO (1) WO1998005706A1 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6476137B1 (en) * 1998-04-16 2002-11-05 Cryovac, Inc. Ternary polymer blend, the film containing it, and the easy-to-open package made therewith
US6630237B2 (en) 2001-02-05 2003-10-07 Cryovac, Inc. Peelably sealed packaging
WO2005044903A1 (fr) * 2003-10-28 2005-05-19 3M Innovative Properties Company Film pour transporter un liquide
WO2013188265A1 (fr) * 2012-06-13 2013-12-19 24M Technologies, Inc. Compositions de boues électrochimiques et leurs procédés de préparation
WO2018223357A1 (fr) * 2017-06-09 2018-12-13 Dow Global Technologies Llc Films multicouches et stratifiés contenant des agents glissants
WO2018223358A1 (fr) * 2017-06-09 2018-12-13 Dow Global Technologies Llc Films multicouches et stratifiés contenant des agents de glissance
US11005087B2 (en) 2016-01-15 2021-05-11 24M Technologies, Inc. Systems and methods for infusion mixing a slurry based electrode

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US6476137B1 (en) * 1998-04-16 2002-11-05 Cryovac, Inc. Ternary polymer blend, the film containing it, and the easy-to-open package made therewith
US6630237B2 (en) 2001-02-05 2003-10-07 Cryovac, Inc. Peelably sealed packaging
WO2005044903A1 (fr) * 2003-10-28 2005-05-19 3M Innovative Properties Company Film pour transporter un liquide
WO2013188265A1 (fr) * 2012-06-13 2013-12-19 24M Technologies, Inc. Compositions de boues électrochimiques et leurs procédés de préparation
US9484569B2 (en) 2012-06-13 2016-11-01 24M Technologies, Inc. Electrochemical slurry compositions and methods for preparing the same
US12368157B2 (en) 2012-06-13 2025-07-22 24M Technologies, Inc. Electrochemical slurry compositions and methods for preparing the same
US11005087B2 (en) 2016-01-15 2021-05-11 24M Technologies, Inc. Systems and methods for infusion mixing a slurry based electrode
US11961990B2 (en) 2016-01-15 2024-04-16 24M Technologies, Inc. Systems and methods for infusion mixing a slurry-based electrode
WO2018223358A1 (fr) * 2017-06-09 2018-12-13 Dow Global Technologies Llc Films multicouches et stratifiés contenant des agents de glissance
US11090852B2 (en) 2017-06-09 2021-08-17 Dow Global Technologies Llc Multilayer films and laminates containing slip agents
CN110740865B (zh) * 2017-06-09 2022-04-19 陶氏环球技术有限责任公司 含有滑移剂的多层膜以及层压材料
US11338563B2 (en) 2017-06-09 2022-05-24 Dow Global Technologies Llc Multilayer films and laminates containing slip agents
CN110740865A (zh) * 2017-06-09 2020-01-31 陶氏环球技术有限责任公司 含有滑移剂的多层膜以及层压材料
WO2018223357A1 (fr) * 2017-06-09 2018-12-13 Dow Global Technologies Llc Films multicouches et stratifiés contenant des agents glissants

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