Polyethylene extrusion coating compositions
AssigneeEastman Kodak Company
InventorRay Edwards
Life of this patent
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Abstract
This invention relates to novel low density polyethylene containing blends useful as extrusion coating compositions which provide coatings having good coatability and a broad heat seal range. These coated substrates then can be used in fabricating bags and other packaging applications. These coatings contain a blend of low density polyethylene and a degraded crystalline polypropylene or propylene containing copolymer.
Claims18
An extrusion coating composition having a melt index of 2 to 20 dg/min. at 190.degree. C. which provides coatings on substrates having broad heat seal range comprising a blend of:
- (1) about 5 to 30 percent, by weight, of at least one degraded crystalline polypropylene or ethylene/propylene copolymer containing less than 5 weight percent ethylene, having a melt flow rate of 5 to 55 dg/min. at 230.degree. C., and (2) about 95 to 70 percent, by weight, of at least one polyethylene having a density of 0.916 to 0.920, a melt index at 190.degree. C. of 10 to 20, and a melt index recovery of greater than 50.
An extrusion coating composition according to claim 5 wherein said degraded ethylene/propylene copolymer has a melt flow rate of 30 at 230.degree. C.
An extrusion coating composition having a melt index of 2 to 20 dg/min. at 190.degree. C. which provides coatings of less than 1 mil which have heat seal strengths of at least 10 pounds per linear inch comprising a blend of:
- (1) about 10 to 20 percent, by weight, of at least one degraded crystalline polypropylene or ethylene/propylene copolymer containing less than 5 weight percent ethylene, having a melt flow rate of 5 to 55 dg/min. at 230.degree. C., and (2) about 90 to 80 percent, by weight, of at least one polyethylene having a density of about 0.916 to about 0.920, a melt index at 190.degree. C. of 10 to 20, and a melt index recovery of greater than 50.
An extrusion coating composition having a melt index of 12 dg/min. at 190.degree. C. which provides coatings of less than 1 mil which have heat seal strengths of at least 10 pounds per linear inch comprising a blend of:
- (1) about 10 percent, by weight, of at least one degraded crystalline polypropylene or ethylene/propylene copolymer containing less than 5 weight percent ethylene, having a melt flow rate of 35 dg/min. at 230.degree. C., and (2) about 90 percent, by weight, of at least one polyethylene having a density of about 0.917, a melt index at 190.degree. C. of 13, and a melt index recovery of 70.
Dependencies are inferred from the claim text.