Coating process and article

Abstract

A thermoplastic polymer advanceable by solid state polymerization is blended with at least one dissimilar thermoplastic polymer, or an organic or inorganic particulate filler. The blend is solid state polymerized to provide a modified polymer alloy or filled polymer blend having at least one physical or chemical property different from that of the blend before solid state polymerization. A substrate is coated with an adherent layer of the modified polymer alloy or filled polymer blend. The modified polymer alloy or filled polymer blend may also be coextruded with a layer of thermoplastic extrusion polymer having a melt viscosity similar to that of the modified polymer alloy or filled polymer blend and applied to a substrate to form an adherent coating.

1 . A process for coating a substrate with an adherent coating comprising:
 a) providing a thermoplastic polymer advanceable by solid state polymerization;   b) blending the thermoplastic polymer with:
 i) at least one dissimilar thermoplastic polymer not advanceable by solid state polymerization, or 
 ii) an organic or inorganic particulate filler; 
   c) solid state polymerizing the advanceable thermoplastic polymer to provide a modified polymer alloy or filled polymer blend having at least one physical or chemical property different from that of the alloy or blend before solid state polymerization; and   d) coating the substrate with an adherent layer of the modified polymer alloy or filled polymer blend.   
     
     
         2 - 15 . (canceled) 
     
     
         16 . 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:
 i) at least one dissimilar thermoplastic polymer, or 
 ii) an organic or inorganic particulate filler; 
   d) solid state polymerizing the second thermoplastic polymer to provide a modified polymer alloy or filled polymer blend whose melt viscosity at the chosen temperature and extrusion rate is sufficiently close to the given value so that the modified polymer alloy or filled polymer blend and the first thermoplastic polymer may be coextruded; and   e) coextruding a layer of the modified polymer alloy or filled polymer blend and a layer of the first thermoplastic polymer onto the substrate to form an adherent coating.   
     
     
         17 . A process according to  claim 16  wherein the second thermoplastic polymer comprises a condensation polymer. 
     
     
         18 . A process according to  claim 16  wherein the second thermoplastic polymer comprises an alkyd. 
     
     
         19 . A process according to  claim 16  wherein the dissimilar thermoplastic polymer is advanceable by solid state polymerization. 
     
     
         20 . A process according to  claim 16  wherein the dissimilar thermoplastic polymer is not advanceable by solid state polymerization. 
     
     
         21 . A process according to  claim 16  comprising blending the second thermoplastic polymer with the at least one dissimilar thermoplastic polymer. 
     
     
         22 . A process according to  claim 21  wherein the second thermoplastic polymer comprises a polyester and the dissimilar thermoplastic polymer comprises a copolyester. 
     
     
         23 . A process according to  claim 21  wherein the second thermoplastic polymer comprises polyethylene terephthalate, the dissimilar thermoplastic polymer comprises a copolyester and the modified polymer alloy or filled polymer blend has greater melt viscosity than that of the alloy or blend before solid state polymerization. 
     
     
         24 . A process according to  claim 16  wherein the modified polymer alloy or filled polymer blend 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 Pa-sec. 
     
     
         25 . A process according to  claim 16  wherein the modified polymer alloy or filled polymer blend has a melt viscosity within about ±5% of the first thermoplastic polymer at temperatures of about 200-300° C. and shear rates of about 50-500 Pa-sec. 
     
     
         26 . A process according to  claim 16  comprising coextruding onto the substrate a first layer containing polyethylene terephthalate and a copolyester, a second layer containing polyethylene terephthalate, and a third layer containing polyethylene terephthalate and a copolyester. 
     
     
         27 . A process according to  claim 16  comprising blending the second thermoplastic polymer with the inorganic particulate filler. 
     
     
         28 . A process according to  claim 27  wherein the inorganic particulate filler comprises a metal oxide. 
     
     
         29 . A process according to  claim 16  wherein the blending step comprises melt-blending. 
     
     
         30 . A process according to  claim 16  wherein the substrate comprises steel. 
     
     
         31 . A coated article comprising a substrate having adhered thereto one or more polymeric layers, wherein at least one layer comprises a modified polymer alloy or filled polymer blend comprising a thermoplastic polymer and (i) at least one dissimilar polymer not advanceable by solid state polymerization or (ii) an organic or inorganic particulate filler, wherein the thermoplastic polymer has been advanced by solid state polymerization and the alloy or blend has a melt viscosity greater than that of the alloy or blend before solid state polymerization. 
     
     
         32 . A coated article according to  claim 31  wherein the thermoplastic polymer comprises a condensation polymer. 
     
     
         33 . A coated article according to  claim 31  wherein the thermoplastic polymer comprises an alkyd. 
     
     
         34 . A coated article according to  claim 31  wherein the modified polymer alloy or filled polymer blend comprises a thermoplastic polymer and at least one dissimilar polymer. 
     
     
         35 . (canceled) 
     
     
         36 . A coated article according to  claim 31  wherein the modified polymer alloy or filled polymer blend has a melt viscosity within about ±15% of the dissimilar polymer at temperatures of about 200-300° C. and shear rates of about 50-500 Pa-sec. 
     
     
         37 . A coated article according to  claim 31  wherein the blend comprises the thermoplastic polymer and the organic particulate filler. 
     
     
         38 . A coated article according to  claim 31  wherein the blend comprises the thermoplastic polymer and the inorganic particulate filler. 
     
     
         39 . A coated article according to  claim 38  wherein the inorganic particulate filler comprises a metal oxide. 
     
     
         40 . A coated article according to  claim 31  wherein the substrate comprises steel.