Low temperature multi-layer extrusion coating process
AssigneeEastman Kodak Company
InventorJohn W. Cook
Life of this patent
Estimating the term…
Abstract
Process for applying multi-layer extrusion coatings to substrate at low temperature is described, employing as one extrusion coating layer a defined polyethylene-containing component, and, as the second extrusion coating layer at least one second extrudable polymeric composition. Also provided are novel extrusion coated articles comprising substrate having coated thereon defined polyethylene-containing component and at least one other extrudable polymeric composition. These articles display good adhesion of extrusion coating material to the substrate without the degradation of the extrudable coatings caused by exposure to excessive levels of heat as is required for successful extrusion coating employing prior art materials.
Claims19
A process for the low-temperature multi-layer extrusion coating of a substrate with a first, polyethylene-coating layer which is subjected to a temperature no greater than about 480.degree. F., and at least one additional layer comprising at least one second extrudable composition, said process comprising:
- applying to at least one surface of said substrate a polyethylene-containing composition to form said first, polyethylene-containing layer, comprising:
- (a) a polyethylene component having a melt index in the range of about 10 up to 100 dg per minute at 190.degree. C. and having a sufficiently broad molecular weight distribution so that the resulting composition is capable of being extrusion coated at a temperature less than about 480.degree. F. to a thickness as thin as 0.0003 inches (0.0075 mm) at a speed of at least 1000 feet per minute (300 meters per minute), and
- (b) in the range of about 5 up to 15 wt %, based on the weight of the total composition, of a hydrocarbon tackifying resin having a Ring and Ball Softening Point in the range of about 125.degree. up to 140.degree. C., and
- at least one second extrudable composition selected from:
- polyethylenes having a melt index different than the melt index of said first polyethylene component,
- polyethylenes having a density different than the density of said first polyethylene component,
- polyethylenes modified with polymer additives,
- polypropylene homopolymers, comonomers, copolymers, and terpolymers, optionally modified with polymer additives,
- polyethylene comonomers, copolymers and terpolymers, including extrudable ionomers, optionally modified with polymer additives,
- extrudable polymers of higher olefins having in the range of 4 up to 8 carbon atoms, optionally modified with polymer additives,
- extrudable polyvinylidene chloride, optionally modified with polymer additives,
- extrudable polyamides, optionally modified with polymer additives, or
- extrudable polyesters, optionally modified with polymer additives;
- wherein said process is carried out by multi-layer extrusion coating of said substrate;
- and wherein the temperature of said polyethylene-containing composition is no greater than about 480.degree. F. during the extrusion process.
Dependencies are inferred from the claim text.