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AssigneeNone recorded
InventorsINGRID COLE, CHARLES W. PAUL, BRIAN MORRISON
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A bag formed utilizing a hot melt adhesives comprising (a) 20 to 70 parts ethylene/alpha olefin polymer having a melt index of 50 to 500 MI, a melt point of 71 to 90° C., a density of 0.885 to 0.90, a composition distribution breadth index greater than 50%, and Mw/Mn less than 6; (b) 10 to 50 parts tackifier; and (c) 0 to 30 parts wax.
A bag formed utilizing a hot melt adhesive composition, said adhesive composition comprising:
A hot melt adhesive composition comprising:
An adhesive according to 8 wherein the ethylene/alpha olefin polymer is an ethylene/butene copolymer having a density of 0.901 and melt index of 125.
Dependencies are inferred from the claim text.
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Copolymers of ethene with unsaturated hydrocarbons only containing more than three carbon atoms: copolymers of ethene with aliphatic 1-olefins
Compositions of oils, fats or waxes; Compositions of derivatives thereof: waxes
Hollow or container type article [e.g., tube, vase, etc.]: nonself-supporting tubular film or bag [e.g., pouch, envelope, packet, etc.]
Adhesives
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Hot melt adhesives, 100% solids materials, which are applied to a substrate when molten and cooled to harden the adhesive layer, are widely used for industrial applications.
Current technology relies on either polyethylene or ethylene vinyl acetate (“EVA”) based adhesives. EVA based adhesives offer good adhesion to difficult substrates such as fluorocarbon coated papers. The disadvantage of this type of adhesive is that it will retack at elevated temperatures.
Therefore, if used as a preapplied heat seal on bags, the bags can block together when stacked on a pallet. This type of blocking is predominately seen on bags with UV, waterborne and solvent borne coatings, and on Kraft bags.
In the following examples, the following procedures were used:
FX 845 and FC807 are fluorocarbon coated paper used in bags and as a grease proof coating. Adhesion to FC807 and FX 845 coated papers was measured by applying a bead of adhesive at 350° F., 0.12 in. uncompressed, to the fluorocarbon and mating to a clay coated side. Bonds are aged 24 hours at room temperature, 40° F., 20° F., and 0° F., and pulled by hand. Fiber tear, (%) is then accessed.
Block resistance was measured by preapplying 5 to 7 mil films of adhesive at 350° F. to Kraft UV coated bags. After 24 hours, these bags are cut to 2×2 inch squares and stacked on top of each other. Typically four sheets are stacked together in an oven at 170° F., with a 3.75 lb/in2 force placed on the stack. After 24 hours, the weight is removed and blocking, ink lift, and fiber tear are accessed as the stacks are pulled apart.