CA2684676C

Easy opening packaging article made from heat-shrinkable film exhibiting directional tear

Abstract

A packaging article has tear initiators for initiating a manual tear that can be propagated to open a package and allow a product to be readily removed therefrom, without the use of a knife or scissors or any other implement. The packaging article is made from a heat-shrinkable multilayer film having at least one layer containing an incompatible polymer blend, and/or a layer containing an inorganic filler, and/or a layer having a high Young's modulus. The film also has a Peak Load Impact Strength of at least 50 Newtons per mil, The tear initiators can be used to generate a manual machine direction tears to open the package, with the manual machine direction tear being capable of propagating in the machine direction to the opposite edge of the packaging article. A process for making a package and manually opening the package is also disclosed.

CA2684676C, drawing sheet 1
Sheet 1 of 17

Term

1.7 yearsleft in the term

Expires 20 May 2028.

  1. Priority and filed
  2. Granted
  3. Today
  4. Expires

27 claims: 3 independent, 24 dependent

  1. 1
    CLAIMS:1. A heat-shrinkable packaging article comprising a heat-shrinkable multilayer film having an inside seal layer heat sealed to itself at a heat seal, the article further comprising a first side, a second side, and a skirt or header outward of the heat seal, the skirt or header comprising an article edge and a first tear initiator, the first tear initiator being in the first side of the article, the article skirt or header also comprising a second tear initiator, the second tear initiator being in the second side of the article, the article being capable of having a manually-initiated, manually-propagated first tear in the first side of the article, and a manually-initiated, and manually-propagated second tear in the second side of the article, the first tear and the second tear each being capable of being propagated in a machine direction from the respective first and second tear initiators, with each tear being propagated in the machine direction through the heat seal and down the length of the article, or across the article, with each tear being capable of being manually propagated in the machine direction through and to an opposite article edge after shrinking the film around a product, so that upon using the multiplayer film to make a packaged product by providing the product inside the article with the article being sealed closed around the product so that a package is formed, and thereafter shrinking the film around the product, the resulting package is capable of being manually opened, and the product readily removed from the article, by manually initiating machine-direction tears from the first and second tear initiators, with the tears being manually propagated through the seal and down the length of the article, for a distance up to the full length of the article and to the opposite edge of the article, with the multilayer film exhibiting a Peak Load Impact Strength of at least 50 Newtons per mil (1968.5 Newtons per mm) measured using ASTM D 3763-95A, with at least one layer of the multilayer film containing at least one incompatible polymer blend selected from the group consisting of: (A) a blend of from 90 to 30 weight percent ethylene homopolymer and/or ethylene/alphaolefin copolymer with from 10 to 70 weight percent ethylene/unsaturated ester copolymer having an unsaturated ester content of at least 10 weight percent;(B) a blend of ionmer resin with ethylene/unsaturated ester copolymer, and/or CA 02684676 2014-06-16 64536-1180 polybutylene, and/or propylene homopolymer and/or propylene copolymer;(C) a blend of homogeneous ethylene/alpha-olefin copolymer with recycled polymer blend comprising ethylene homopolymer, propylene homopolymer, ethylene copolymer, propylene copolymer, polyamide, ethylene/vinyl alcohol copolymer, ionomer resin, anhydride-modified 5 ethylene/alpha-olefin copolymer, and/or antiblock;(D) a blend of from 10 to 75 weight percent ethylene/unsaturated ester copolymer with from 90 to 15 weight percent polypropylene and/or propylene/ethylene copolymer, and/or polybutylene, and/or modified ethylene/alpha-olefin copolymer, and/or styrene homopolymer, and/or styrene/butadiene copolymer;10 (E) a blend of from 90 to 15 weight percent ethylene/alpha-olefin copolymer with from 10 to 75 weight percent polypropylene and/or polybutylene;(F) a blend of from 90 to 25 weight percent homogeneous propylene homopolymer and/or homogeneous propylene copolymer with from 10 to 75 weight percent homogeneous ethylene/alpha-olefin copolymer and/or ethylene/unsaturated ester copolymer;15 (G) a blend of propylene homopolymer and/or propylene/ethylene copolymer and/or polybutylene with ethylene/methyl acrylate copolymer and/or ethylene/acrylic acid copolymer and/or ethylene/butyl acrylate copolymer;and (H) a blend of polyamide with polystyrene and/or ethylene/alpha-olefin copolymer and/or ethylene/vinyl acetate copolymer and/or styrene/butadiene copolymer;and 20 (I) a blend of polyamide 6 and polyamide 6I6T;and wherein the packaging article does not comprise a patch thereon, and wherein the.multilayer film has a thickness, before shrinking, of from 1.5 to 10 mils (0.038 to 0.254 mm).
  2. 2
    The heat-shrinkable packaging article according to claim 1, wherein the CA 02684676 2014-06-16 64536-1180 incompatible blend comprises a blend of ethylene/alpha-olefin copolymer and ethylene/vinyl acetate copolymer having a vinyl acetate content of from 10 to 50 weight percent based on copolymer weight, the blend containing the ethylene/alpha-olefin copolymer in an amount of from 80 to 35 weight percent based on blend weight and ethylene/vinyl acetate copolymer in an amount of from 20 to 65 weight percent based on blend weight, the multilayer film containing the blend in an amount of from 20 to 95 weight percent, based on the weight of the multilayer film, and wherein the multilayer film has been biaxially oriented in the solid state and has a total free shrink, as measured by ASTM D 2732, of from 15 percent to 120 percent at 185°F (85°C).
  3. 5
    The heat-shrinkable packaging article according to claim 3, wherein the CA 02684676 2014-06-16 64536-1180 incompatible blend comprises a blend of ethylene/alpha-olefin copolymer and ethylene/vinyl acetate copolymer having a vinyl acetate content of from 12 to 30 weight percent, the blend containing the ethylene/alpha-olefin copolymer in an amount of from 70 to 50 percent based on blend weight and ethylene/vinyl acetate copolymer in an amount of from 30 to 50 weight percent based on blend weight, the multilayer film containing the blend in an amount of from 30 to 70 weight percent, based on the weight of the multilayer film, and wherein the multilayer film has been biaxially oriented in the solid state and has a total free shrink, as measured by ASTM D 2732, of from 40 percent to 100 percent at 185°F (85°C).
  4. 6
    The heat-shrinkable packaging article according to any one of claims 1 to 5, wherein the packaging article is a lay-flat, end-seal bag made from a seamless tubing, the endseal bag having an open top, first and second folded side edges, and an end seal across a bottom of the bag, with the first and second tear initiators being in the bag skirt that is outward of the end seal, with the first tear being a machine-direction tear of the film, and the second tear being a machine-direction tear of the film, with each tear being capable of being manually propagated down the length of the end-seal bag to the opposite edge of the end-seal bag.
  5. 7
    The heat-shrinkable packaging article according to any one of claims 1 to 5, wherein the packaging article is a lay-flat, side-seal bag made from a seamless tubing, the side-seal bag having an open top, a folded bottom edge, and first and second side seals with respective first and second bag skirts outward of respective first and second side seals, with the first and second tear initiators being in the first bag skirt and outward of the first side seal, with the first tear being a machine-direction tear and the second tear being a machinedirection tear, with each tear being capable of being manually propagated across the full width of the side-seal bag to the opposite edge of the side-seal bag.
  6. 8
    The heat-shrinkable packaging article according to any one of claims 1 to 5, wherein the packaging article is a lay-flat, side-seal bag made from a seamless tubing, the side-seal bag having an open top, a folded bottom edge, a first side seal with a first bag skirt outward thereof, a second side seal with a second bag skirt outward thereof, and a third seal that extends from the first side seal to the second side seal, the third seal being at an opposite CA 02684676 2014-06-16 64536-1180 end of the bag from the open top, the third seal having a third bag skirt outward thereof, the folded bottom edge being in the third bag skirt, the third bag skirt comprising the first and second tear initiators, with the first tear being a transverse-direction tear and the second tear being a transverse-direction tear, with the first and second tears each being capable of being manually propagated down the length of the side-seal bag and to the opposite edge of the sideseal bag.
  7. 9
    The heat-shrinkable packaging article according to any one of claims 1 to 5, wherein the packaging article is a lay-flat pouch made by heat sealing two flat films to one another, the pouch having an open top, a first side seal with a first bag skirt outward thereof, a second side seal with a second bag skirt outward thereof, a bottom seal with a third bag skirt outward thereof, the bottom seal extending from the first side seal to the second side seal, the bottom seal being at an opposite end of the bag from the open top, with at least one of the bag skirts having first and second tear initiators for tearing each of the two flat films in the machine direction.
  8. 10
    The heat-shrinkable packaging article according to any one of claims 1 to 5, wherein the first and second tear initiators are positioned adjacent the top edge of the bag in the header region.
  9. 11
    The heat-shrinkable packaging article according to any one of claims 1 to 10, wherein the heat-shrinkable multilayer film exhibits a Peak Load Impact Strength, determined using ASTM D 3763-95 A, of from 50 to 250 Newtons per mil (1968.5 to 9842 Newtons per mm), and the multilayer film has a total thickness, before shrinking, of from 1.5 mils to 5 mils (0.038 to 0.127 mm).
  10. 12
    The heat-shrinkable packaging article according to any one of claims 1 to 11, wherein the first tear initiator is coincident or substantially coincident with the second tear initiator.
  11. 14
    The heat-shrinkable packaging article according to any one of claims 1 to 13, wherein the packaging article further comprises a grip assister for assisting grip of the multilayer film during manual tearing.
  12. 16
    The heat-shrinkable packaging article according to any one of claims 1 to 15, wherein the multilayer film comprises a barrier layer containing at least one member selected from the group consisting of poly vinylidene chloride, saponified ethylene/vinyl acetate copolymer, amorphous polyamide, polyamide MXD6, polyester, and polyacrylonitrile.
  13. 17
    The heat-shrinkable packaging article according to any one claims 1 to 16, 15 wherein the multilayer film comprises:(A) a first layer that is an outer food-contact layer and that also serves as a seal layer, the first layer comprising homogeneous ethylene/alpha-olefin copolymer;(B) a second layer comprising ethylene/methyl acrylate copolymer;(C) a third layer comprising a blend of polyamide 6 with polyamide 6I6T;20 (D) a fourth layer comprising EVOH;(E) a fifth layer comprising a blend of polyamide 6 with polyamide 6I6T;(F) a sixth layer comprising ethylene/methyl acrylate copolymer;and CA 02684676 2014-06-16 64536-1180 (G) a seventh layer comprising a blend of low density polyethylene and linear low density polyethylene;and wherein the layers are present in the order of first/second/third/fourth/fifth/sixth/seventh. 5
  14. 18
    The heat-shrinkable packaging article according to any one of claims 1 to 16, wherein the multilayer film comprises:(A) a first layer that is an outer food-contact layer and that also serves as a seal layer, the first layer comprising a blend of ethylene/vinyl acetate copolymer, linear low density polyethylene, and homogeneous ethylene/alpha-olefin copolymer;10 (B) a second layer comprising polyvinylidene chloride;(C) a third layer that comprises a blend of ethylene/vinyl acetate copolymer, linear low density polyethylene, and homogeneous ethylene/alpha-olefin copolymer;and wherein the layers are present in the order of first/second/third.
  15. 19
    The heat-shrinkable packaging article according to any one of claims 1 to 16, 15 wherein the multilayer film comprises:(A) a first layer that is an outer food-contact layer and that also serves as a seal layer, the first layer comprising a blend of homogeneous ethylene/alpha-olefin copolymer and linear low density polyethylene;(B) a second layer comprising a blend of heterogeneous ethylene/alpha-olefin copolymer and 20 ethylene/vinyl acetate copolymer;(C) a third layer comprising ethylene/vinyl acetate copolymer;(D) a fourth layer comprising polyvinylidene chloride;(E) a fifth layer comprising ethylene/vinyl acetate copolymer;CA 02684676 2015-03-18 64536-1180 (F) a sixth layer comprising a blend of heterogeneous ethylene/alpha-olefin copolymer and ethylene/vinyl acetate copolymer;and (G) a seventh layer comprising a blend of homogeneous ethylene/alpha-olefin copolymer and linear low density polyethylene;and wherein the layers are present in the order of first/second/third/fourth/fifth/sixth/seventh.
  16. 20
    A heat-shrinkable packaging article comprising a heat-shrinkable multilayer film having an inside seal layer heat sealed to itself at a heat seal, the article further comprising a first side, a second side, and a skirt or header outward of the heat seal, the skirt or header comprising an article edge and a first tear initiator, the first tear initiator being in the first side of the article, the article skirt or header also comprising a second tear initiator, the second tear initiator being in the second side of the article, the article being capable of having a manually-initiated, manually-propagated first tear in the first side of the article, and a manually-initiated and manually-propagated second tear in the second side of the article, the first tear and the second tear each being capable of being propagated in a machine direction from the respective first and second tear initiators, with each tear being propagated in the machine direction through the heat seal and down the length of the article, or across the article, with the tear being capable of being manually propagated in the machine direction through and to an opposite article edge, so that upon using the multilayer film to make a packaged product by providing a product inside the article with the article being sealed closed around the product so that a package is formed, and thereafter shrinking the film around the product, the resulting package is capable of being manually opened, and the product readily removed from the article, by manually initiating machine-direction tears from the first and second tear initiators, with the tears being manually propagated through the seal and toward the opposite edge of the article, with the multilayer film exhibiting a Peak Load Impact Strength of at least 50 Newtons per mil (1968.5 Newtons per mm) measured using ASTM D 3763-95A, wherein at least one layer of the multilayer film comprises a polymer having a Young's modulus of at least 80,000 psi (344750 Pa), wherein the polymer comprises at least CA 02684676 2015-12-09 64536-1180 one member selected from the group consisting of high density polyethylene, ultra high molecular weight polyethylene, polypropylene, styrene copolymer, polycarbonate, and polyester, and wherein the packaging article does not comprise a patch thereon, and wherein multilayer film has thickness before shrinking of from 1.5 to 10 mils (0.038 to 0.254 mm).
  17. 22
    A process for making an easy-open packaged product, comprising:(A) inserting a product into a lay-flat packaging article comprising a heat-shrinkable multilayer film, the packaging article having a first side and a second side;(B) sealing the packaging article closed with at least one heat seal, thereby forming a packaged product in which the packaging article surrounds or substantially surrounds the product, with the packaging article having at least one header portion between the at least one heat seal and at least one edge of the package;(C) making a first tear initiator at a first location of the packaging article that is, or later becomes, a header portion of a first side of the packaging article, and a second tear initiator at a second location of the packaging article that is, or later becomes, the header portion of a second side of the packaging article, wherein the first side of the packaging article corresponds with a first lay-flat side of the packaging article, and the second side of the packaging article corresponds with a second lay-flat side of the packaging article;and (D) heating the heat-shrinkable film to shrink the packing article around the product;and wherein the heat-shrinkable multilayer film exhibits a Peak Load Impact Strength, determined using ASTM D 3763-95A, of at least 50 Newtons per mil (1968.5 Newtons per mm), and the heat-shrinkable, multilayer film is capable of having a CA 02684676 2015-12-09 64536-1180 manually-initiated, manually-propagated first tear in the first side of the packing article, and a manually-initiated, manually-propagated second tear in the second side of the packing article, the first tear and the second tear each being capable of being propagated in a machine direction from the respective first and second tear initiators, with each tear being propagated 5 in the machine direction through the heat seal and across the respective side of the packing article, or down the length of the respective side of the packing article, with the first and second tears each being capable of being manually-propagated in the machine direction through and to an opposite edge of the packing article after heating the heat-shrinkable film to shrink the film around the product, so that the packing article is capable of being heat10 shrinkable manually opened, and the product removed therefrom, with the multilayer film having at least one layer containing at least one incompatible polymer blend selected from the group consisting of: (A) a blend of from 90 to 30 weight percent ethylene homopolymer and/or ethylene/alphaolefin copolymer with from 10 to 70 weight percent ethylene/unsaturated ester copolymer 15 having an unsaturated ester content of at least 10 weight percent;(B) a blend of ionomer resin with ethylene/unsaturated ester copolymer, and/or polybutylene, and/or propylene homopolymer and/or propylene copolymer;(C) a blend of homogeneous ethylene/alpha-olefin copolymer with recycled polymer blend comprising ethylene homopolymer, propylene homopolymer, ethylene copolymer, propylene 20 copolymer, polyamide, ethylene/vinyl alcohol copolymer, ionomer resin, anhydride-modified ethylene/alpha-olefin copolymer, and/or antiblock;(D) a blend of from 10 to 75 weight percent ethylene/unsaturated ester copolymer with from 90 to 15 weight percent polypropylene and/or propylene/ethylene copolymer, and/or polybutylene, and/or modified ethylene/alpha-olefin copolymer, and/or styrene homopolymer, 25 and/or styrene/butadiene copolymer;(E) a blend of from 90 to 15 weight percent ethylene/alpha-olefin copolymer with from 10 to 75 weight percent polypropylene and/or polybutylene;CA 02684676 2015-12-09 64536-1180 . 70 (F) a blend of from 90 to 25 weight percent homogeneous propylene homopolymer and/or homogeneous propylene copolymer with from 10 to 75 weight percent homogeneous ethylene/alpha-olefin copolymer and/or ethylene/unsaturated ester copolymer;(G) a blend of propylene homopolymer and/or propylene/ethylene copolymer and/or 5 polybutylene with ethylene/methyl acrylate copolymer and/or ethylene/acrylic acid copolymer and/or ethylene/butyl acrylate copolymer;and (H) a blend of polyamide with polystyrene and/or ethylene/alpha-olefin copolymer and/or ethylene/vinyl acetate copolymer and/or styrene/butadiene copolymer;and (I) a blend of polyamide 6 and polyamide 6I6T;and 10 wherein the packaging article does not comprise a patch thereon, and wherein the multilayer film has a thickness, before shrinking, of from 1.5 to 10 mils (0.038 to 0.254 mm).
  18. 25
    The process according to any one of claims 22 to 24, further comprising 20 evacuating atmosphere from within the packaging article after inserting the product into the packaging article, but before sealing the article closed.
  19. 27
    A plurality of heat-shrinkable bags in a continuous strand, each of the bags being connected to an adjacent bag along a weakened tear line, wherein each bag is a heatshrinkable packaging article according to any one of claims 1 to 21, and wherein the article skirt or header is a bag skirt. 5 28. A process for making a package and manually opening the package, comprising:(A) placing a product inside a heat-shrinkable packaging article according to any one of claims 1 to 21;(B) sealing the packaging article closed so that a package is formed;and 10 (C) manually-initiating and manually-propagating a first tear in the first side of the bag, and a second tear in the second side of the bag, the first tear and the second tear each being manually-propagated from the respective first and second tear initiators, with each tear being manually-propagated through the heat seal and across the bag, or down the length of the bag, with the first and second tears being manually propagated towards an opposite edge of the 15 packaging article, so that the product is capable of being readily removed from the bag, the process being carried out without shrinking the film around the product. CA 02684676 2009-11-09 WO 2008/144059 PCT/US2008/006444 1/29
Independent claims19