Patent ID: 8790787
Filing Date: 2014-07-29
Classification: C08L,C09D,Y02P,Y10T

Abstract:
1. A process for applying an adherent multilayer coating to a substrate comprising: a) providing a first thermoplastic polymer whose melt viscosity has a given value at a chosen temperature and extrusion rate; b) providing a second thermoplastic polymer advanceable by solid state polymerization and having a melt viscosity at the chosen temperature and extrusion rate sufficiently unlike the given value so that the first and second thermoplastic polymers can not be coextruded; c) blending the second thermoplastic polymer with at least one dissimilar thermoplastic polymer; d) solid state polymerizing the resulting blend to provide a modified polymer alloy whose melt viscosity at the chosen temperature and extrusion rate is sufficiently close to the given value so that the modified polymer alloy and the first thermoplastic polymer may be coextruded, wherein the modified polymer alloy has a melt viscosity within about ±15% of the first thermoplastic polymer at temperatures of about 200-300° C. and shear rates of about 50-500 l/s; and e) coextruding a layer of the modified polymer alloy and a layer of the first thermoplastic polymer onto a metal substrate to form a coated substrate having an adherent multilayer coating on the substrate.