EP2349867B1

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

Abstract

This record has no abstract on file.

EP2349867B1, drawing sheet 1
Sheet 1 of 36

Term

3.2 yearsleft in the term

Expires 20 November 2029.

  1. Priority
  2. Filed
  3. Granted
  4. Today
  5. Expires

14 claims: 1 independent, 13 dependent

  1. 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 having a first side and a second side, the article having a skirt or header outward of the heat seal, the skirt or header comprising an article edge and a pair of tear initiators, the pair of tear initiators having a first tear initiator and a second tear initiator, the first tear initiator of the pair being in the first side of the article, and the second tear initiator of the pair 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 pair of 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, so that upon using the multilayer film to make a packaged product by placing 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 can be manually opened, and the product readily removed from the package, 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 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 80 to 40 weight percent ethylene homopolymer and/or ethylene/alpha-olefin copolymer with from 20 to 60 weight percent ethylene/unsaturated ester copolymer 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 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, and/or styrene/butadiene copolymer;(E) a blend of ethylene/norbornene copolymer with ethylene/unsaturated ester copolymer and/or polypropylene and/or polybutylene;(F) a blend of from 90 to 15 weight percent ethylene/alpha-olefin copolymer with from 10 to 75 weight percent polypropylene and/or polybutylene and/or ethylene/norbornene;(G) 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;(H) 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;(I) a blend of polyamide with polystyrene and/or ethylene/alpha-olefin copolymer and/or ethylene/vinyl acetate copolymer and/or styrene/butadiene copolymer;and (J) a blend of polyamide 6 and polyamide 6I6T;and wherein at least a portion of the skirt or header is heatset with a remainder of the film remaining heat-shrinkable, so that upon forming the package and shrinking the film around the product, the shrinkage and curl of the skirt or header is reduced, and wherein the heat-shrinkable packaging article does not comprise a patch thereon.
  2. 3
    The heat-shrinkable article according to Claim 1, wherein a portion of the skirt or header on the first side of the article is heatset, and a corresponding portion of the skirt or header on the second side of the article is also heat-set, preferably wherein the article is an end-seal bag and the first and second tear initiators are present in the bag skirt, and a heat seal is present within the heatset portion of the first and second sides of the article, more preferably wherein the first tear initiator is aligned over the second tear initiator, and the heat seal present within the heatset portion is a perimeter seal, and the skirt further comprise a first grip assister between the pair of tear initiators and a first end of the skirt, and a second grip assister between the pair of tear initiators and a second end of the skirt.
  3. 4
    The heat-shrinkable article according to Claim 1, wherein a first portion of a first side of the skirt or header is spot sealed to the second side of the skirt or header at a first spot seal, and a second portion of the first side of the skirt or header is spot sealed to the second side of the skirt or header at a second spot seal.
  4. 5
    The heat-shrinkable article according to Claim 1, wherein the heat-set portions of the first and seconds sides of the skirt or header comprise a perimeter seal in the skirt or header, preferably wherein the first tear initiator aligns directly over the second tear initiator, and the skirt or header further comprises a first spot seal within 25.4 mm (1 inch) of the first and second tear initiators and a first end of the skirt, and a second spot seal within 25.4 mm (1 inch) of the first and second tear initiators and a second end of the skirt or header.
  5. 7
    The heat-shrinkable article according to Claim 5, wherein the article is a side seal bag or pouch having a skirt comprising a plurality of pairs of first and second tear initiators, with each first tear initiator being aligned directly over the second tear initiator with which is it paired, preferably (a) wherein the article is a side-seal bag having a skirt that comprises, for each pair of first and second tear initiators, a first spot seal within 25.4 mm (1 inch) of the pair of tear initiators, the first spot seal being between the pair of tear initiators and a first end of the skirt, and a second spot seal within 25.4 mm (1 inch) of the pair of tear initiators, the second spot seal being between the pair of tear initiators and the a second end of the skirt, or (b) wherein the multilayer film has an oxygen transmission rate of at least 50 cc/m 2 day at stp and 0% relative humidity, or (c) wherein the multilayer film has a non-symmetrical polymeric layer arrangement.
  6. 9
    The heat-shrinkable packaging article according to Claim 8, 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 plurality of pairs of tear initiators being spaced apart along the first bag skirt, with each tear being capable of being manually propagated across the full width of the side-seal bag through both side seals and through second skirt.
  7. 10
    The heat-shrinkable packaging article according to Claim 9, wherein at least a portion of a first side of the skirt or header is heat sealed to the second side of the skirt or header in at least one heat seal, preferably either (a) wherein the first side of the skirt or header is heat sealed to the second side of the skirt or header in a plurality of spot seals, or (b) wherein the first side of the skirt or header is heat sealed to the second side of the skirt or header in a heat seal along an outer edge of the skirt or header.
  8. 11
    The heat-shrinkable packaging article according to Claim 9, wherein the plurality of pairs of tear initiators are located at intervals of from 25 mm to 76 mm (1 to 3 inches).
  9. 12
    The heat-shrinkable packaging article according to Claim 8, wherein each of the first tear initiators is coincident or substantially coincident with the second tear initiator with which it is paired, and each of the first tear initiators is a slit through the first side of the article, and each of the second tear initiators is a slit through the second side of the article, and each of the slits is oriented in the machine direction, preferably wherein each of the slits is oriented within 20 degrees of the machine direction.
  10. 13
    The heat-shrinkable packaging article according to Claim 8, 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 20 percent to 105 percent at 85°C (185°F), or wherein the heat-shrinkable multilayer film exhibits a Peak Load Impact Strength, determined using ASTM D 3763-95A, of from 2000 to 10000 N/mm (50 to 250 Newtons per mil), and the multilayer film has a total thickness, before shrinking, of from 0.038 mm (1.5 mils) to 0.13 mm (5 mils), or wherein the multilayer film comprises an O 2 -barrier layer and the multilayer film exhibits an oxygen transmission rate of from 1 to 20 cc/m 2 day atm at 23°C and 100% relative humidity.
  11. 14
    The heat-shrinkable packaging article according to Claim 8, 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 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;(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.