Resealable and Reclosable Packaging Having Reduced-Curl, Pressure-Sensitive Seal Tape

Abstract

A flexible package formed from a film of polymer packaging material having a first and second panels sealed at a top portion and a bottom portion, an elongate slit in the first panel, and an elongate strip of pressure-sensitive-adhesion, re-closing tape (“PSA tape strip”) applied to the surface of said first panel over the slit. The PSA tape strip has an adhesive edge portion abridging and releasably sealing the slit and a non-adhesive edge portion arranged on one side of said slit and lying against the first panel. The PSA tape strip is adapted so that the slit can be unsealed by gripping the non-adhesive edge portion and pulling the PSA tape strip away from the first panel until the adhesive edge portion no longer abridges the slit. The PSA tape strip comprises a base material of polymer film that is compatibly recyclable with said packaging material The PSA tape strip also resists curling when it is strained by pulling it away from said first panel to unseal the slit. Preferably, the PSA tape has secant modulus ratio (machine direction to cross direction) greater than 90%.

1 . A flexible package formed from a film of polymer packaging material, comprising:
 a. a first and second panels sealed at a top portion and a bottom portion;   b. an elongate slit in said first panel; and,   c. an elongate strip of pressure-sensitive-adhesion, re-closing tape (“PSA tape strip”) applied to the surface of said first panel over said slit, said PSA tape strip having an adhesive edge portion abridging and releasably sealing said slit and a non-adhesive edge portion arranged on one side of said slit and lying against said first panel, said PSA tape strip adapted so that said slit can be unsealed by gripping said non-adhesive edge portion and pulling said PSA tape strip away from said first panel until the adhesive edge portion no longer abridges said slit,   wherein said PSA tape strip comprises a base material of polymer film that is compatibly recyclable with said packaging material; and,   wherein said PSA tape strip resists curling when it is strained by pulling it away from said first panel to unseal said slit.   
     
     
         2 . The package recited in  claim 1 , wherein said PSA tape strip comprises a base material of polymer film, a pressure-sensitive adhesive applied to a first side of said base material, and a non-adhesive grip strip of polymer film applied to said adhesive along one edge of said first side of said base material to form said non-adhesive edge portion, and the remainder of said first side forming said adhesive edge portion, wherein said grip strip is compatibly recyclable with said packaging material. 
     
     
         3 . The package recited in  claim 1 , wherein said PSA tape strip comprises a base material of polymer film, a pressure-sensitive adhesive applied to a first side of said base along one edge in a pattern less than the width of said tape strip to form said adhesive edge portion, and the remainder of said first side having no adhesive applied thereto and forming said non-adhesive edge portion. 
     
     
         4 . The package recited in  claim 1 , wherein said PSA tape strip has a percentage curl less than about 5%. 
     
     
         5 . The package recited in  claim 1 , wherein said base material comprises machine-direction-oriented polyethylene film produced from a blown film process having a multilayer film structure of at least 3 but less than 8 layers. 
     
     
         6 . The package recited in  claim 5 , wherein said base material has a stretch ratio of 1:3 but no greater than 1:10. 
     
     
         7 . The package recited in  claim 5 , wherein said base material contains 25 to 65 percent by weight of HDPE, combined with a blend of metallocene LLDPEs and higher alpha olefin LLDPE utilizing butene, hexene, or octane, said blend comprising 10 to 90 percent by weight of metallocene LLDPE. 
     
     
         8 . The package recited in  claim 5 , wherein said base material has a thickness of at least 1.6 mils but less than 2.5 mils. 
     
     
         9 . The package recited in  claim 5 , wherein said base material has a haze value less than 10%. 
     
     
         10 . The package recited in  claim 5 , wherein at least one side of said base has been corona treated to a surface tension of at least 36 dynes/cm but less than 46 dynes/cm. 
     
     
         11 . The package recited in  claim 5 , wherein said base has a secant modulus between 130,000 to 250,000 p.s.i. in the machine direction and 100,000 to 225,000 p.s.i. in the cross direction, and a secant modulus ratio (machine direction to cross direction) greater than 90%. 
     
     
         12 . A resealable, pressure-sensitive-adhesion tape (“PSA tape”) for use in combination with a flexible package formed from a film of polymer packaging material, said PSA tape comprising:
 a. a base material of polyethylene film that is compatibly recyclable with said packaging material; and, 
 b. a pressure sensitive adhesive applied to one side of said base material along one at least a lengthwise-extending edge to form an adhesive edge portion and a non-adhesive edge portion; 
 wherein said PSA tape strip comprises a base material of polymer film that is compatibly recyclable with said packaging material; and, 
 wherein said PSA tape resists curling when it removed from a surface to which it has been adhered by pulling on said non-adhesive edge portion. 
 
     
     
         13 . The PSA tape recited in  claim 12 , including pressure-sensitive adhesive applied to the entirety of one side of said base material, and a grip strip of polymer film applied to said pressure-sensitive adhesive along one edge of said first side of said base material to form said non-adhesive edge portion, and the remainder of said first side forming said adhesive edge portion, wherein said grip strip and said pressure-sensitive adhesive are compatibly recyclable with said packaging material. 
     
     
         14 . The PSA tape recited in  claim 12 , wherein said PSA tape strip has a percentage curl less than about 5%. 
     
     
         15 . The PSA tape recited in  claim 12  having secant modulus ratio (machine direction to cross direction) greater than 90%. 
     
     
         16 . The PSA tape recited in  claim 14 , wherein said base material:
 a. comprises a machine-direction-oriented polyethylene film produced from a blown film process having a multilayer film structure of at least 3 but less than 8 layers;   b. has a stretch ratio of 1:3 but no greater than 1:10;   c. contains 25 to 65 percent by weight of HDPE, combined with a blend of metallocene LLDPEs and higher alpha olefin LLDPE utilizing butene, hexene, or octane, said blend comprising 10 to 90 percent by weight of metallocene LLDPE;   d. has a film thickness of 1.6 mils to 2.5 mils;   e. has a haze value less than 10%;   f. has been corona treated on at least one side to a surface tension of at least 36 dynes/cm but less than 46 dynes/cm; and,   g. has a secant modulus between 130,000 to 250,000 p.s.i. in the machine direction and 100,000 to 225,000 p.s.i. in the cross direction.   
     
     
         17 . The PSA tape recited in  claim 13 , wherein said adhesive coating has a thickness from 0.6 to 1.1 mils. 
     
     
         18 . The PSA tape recited in  claim 17 , wherein said pressure-sensitive adhesive is selected from the group consisting of: solvent based acrylic or rubber based, aqueous based, formulated styrenic isoprene or formulated styrenic butadiene block copolymer hot melt adhesive or Ultra Violet Light (UV C) hot melt acrylics. 
     
     
         19 . The PSA tape recited in  claim 13 , wherein said grip strip comprises either polyethylene or polypropylene film. 
     
     
         20 . The PSA tape recited in  claim 12 , wherein the width of said non-adhesive edge portion is at least ½ in. 
     
     
         21 . The PSA tape recited in  claim 12 , wherein said tape is formed as a continuous roll or a series of segmented labels. 
     
     
         22 . The PSA tape recited in  claim 12 , including pressure-sensitive adhesive applied to the entirety of one side of said base material, and a water based or UV cure deadeners used in the label industry applied to said pressure-sensitive adhesive along one edge of said first side of said base material to form said non-adhesive edge portion, and the remainder of said first side forming said adhesive edge portion. 
     
     
         23 . The PSA tape recited in  claim 14 , wherein said base material comprises a multilayer bi-axially-oriented, polyethylene-based film having:
 a. a core layer formed of a core resin composition comprising a blend of 50 to 90% by weight of a first metallocene linear low density polyethylene (mLLDPE) resin having a melt index from about 0.8 dg/s to about 2 dg/s, about 5-25% by weight of a second mLLDPE resin having melt index from about 0.1 dg/s to about 0.8 dg/s, and about 5-25% by weight of a third mLLDPE resin having a melt index from about 2 dg/s to about 10 dg/s; and   b. a skin layer having a skin resin composition comprising one or more polyolefin plastomers, wherein said skin layer has a thickness of approximately 3% to 20% as compared to a total thickness of the extruded, oriented, multilayer, film structure.   
     
     
         24 . The PSA tape recited in  23 , wherein said film:
 a. has a film thickness of at least 1.6 mils but less than 2.5 mils;   b. has a haze value less than 10%;   c. has at least one side corona treated to a surface tension of at least 36 dynes/cm but less than 46 dynes/cm.   
     
     
         25 . The PSA tape recited in  claim 24 , wherein said pressure-sensitive adhesive:
 a. has a thickness of 0.6 to 1.1 mils; and,   b. is selected from the group consisting essentially of: solvent based acrylic or rubber based, aqueous based, formulated styrenic isoprene or formulated styrenic butadiene block copolymer hot melt adhesive or Ultra Violet Light (UV C) hot melt acrylics.   
     
     
         26 . A resealable, pressure-sensitive-adhesion tape (“PSA tape”) for use in combination with a flexible package formed from a film of polymer packaging material, said PSA tape comprising:
 a. a base material of polyethylene film comprising a machine-direction-oriented polyethylene film produced having a multilayer film structure of at least 3 but less than 8 layers; 
 b. a pressure sensitive adhesive applied to a first side of said base material, said pressure sensitive adhesive selected from the group consisting essentially of: solvent based acrylic or rubber based, aqueous based, formulated styrenic isoprene or formulated styrenic butadiene block copolymer hot melt adhesive or Ultra Violet Light (UV C) hot melt acrylics; 
 c. a non-adhesive grip strip of polymer film applied to said adhesive along one edge of said first side of said base material to form a non-adhesive edge portion, and the remainder of said first side forming an adhesive edge portion, wherein said grip strip comprises either polyethylene or polypropylene film; 
 wherein said PSA tape has secant modulus ratio (machine direction to cross direction) greater than 90%.