High flow rate polyolefin extrusion coating compositions
AssigneeEastman Kodak Company
InventorRay Edwards
Life of this patent
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Abstract
This invention relates to novel blends containing degraded crystalline polypropylene or propylene containing copolymer useful as extrusion coating compositions which provide coatings having good coatability and good heat sealability. These coated substrates then can be used in fabricating bags and other packaging applications. Particularly, these coatings are a blend of a degraded crystalline polypropylene, or propylene containing copolymer, and low density polyethylene.
Claims21
An extrusion coating composition having a flow rate of 5 to 55 dg/min. at 230.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 75 to 95 percent, by weight, of at least one degraded crystalline polypropylene or propylene containing copolymer having a melt flow rate of 5 to 55 dg/min. at 230.degree. C., and (2) about 5 to 25 percent, by weight, of at least one polyethylene having a density of 0.916 to 0.925, a melt index at 190.degree. C. of 0.5 to 4.5, and a melt index recovery of greater than 40.
An extrusion coating composition having a melt flow rate of 5 to 55 dg/min. at 230.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 80 to 90 percent, by weight, of at least one degraded crystalline polypropylene or propylene containing copolymer having a melt flow rate of 5 to 55 dg/min. at 230.degree. C., and (2) about 10 to 20 percent, by weight, of at least one polyethylene having a density of about 0.916 to about 0.925, a melt index at 190.degree. C. of 0.5 to 4.5, and a melt index recovery of greater than 40.
An extrusion coating composition having a melt flow rate of 30 dg/min. at 230.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 90 percent, by weight, of at least one degraded crystalline polypropylene or propylene containing copolymer having a melt flow rate of 30 to 35 dg/min. at 230.degree. C., and (2) about 10 percent, by weight, of at least one polyethylene having a density of about 0.917, a melt index at 190.degree. C. of 3.5, and a melt index recovery of 70.
Dependencies are inferred from the claim text.