Process for preparing thermoplastic elastomer foam and foamed article

Abstract

A thermoplastic elastomer foam is made by incorporating a gaseous or supercritical blowing agent under pressure into a molten thermoplastic elastomer comprising polymeric polymeric crystalline domains, then releasing the pressure to foam the thermoplastic elastomer.

1 .- 28 . (canceled) 
     
     
         29 . A polymeric mixture made by a method comprising:
 providing a polymer melt comprising a molten thermoplastic elastomer and a molten semi-crystalline polymer that is miscible in the molten thermoplastic elastomer; and   cooling the polymer melt to a temperature below a crystallization temperature, wherein the crystallization temperature is a temperature at which regions of the semi-crystalline polymer become immiscible with the thermoplastic elastomer and phase-separate from the thermoplastic elastomer, thereby forming a polymeric mixture comprising the regions of the semi-crystalline polymer distributed in the thermoplastic elastomer;   wherein the semi-crystalline polymer comprises from 0.1 weight percent to 20 weight percent of total polymer weight of the polymeric mixture; and   wherein the semi-crystalline polymer comprises a polymer chosen from nylon 11, nylon 12, or a copolymer of ethylene with at least one vinyl monomer.   
     
     
         30 . The polymeric mixture of  claim 29 , wherein the thermoplastic elastomer comprises a thermoplastic polyurethane elastomer. 
     
     
         31 . The polymeric mixture of  claim 30 , wherein polymeric diol segments of the thermoplastic polyurethane elastomer comprise from 35 weight percent to 65 weight percent of the thermoplastic polyurethane polymer. 
     
     
         32 . The polymeric mixture of  claim 30 , wherein the thermoplastic polyurethane elastomer is chosen from a thermoplastic polyester-polyurethane elastomer, a thermoplastic polyether-polyurethane elastomer, a thermoplastic polycarbonate-polyurethane elastomer, or a thermoplastic polyurethane elastomer comprising polyolefinic segments. 
     
     
         33 . The polymeric mixture of  claim 29 , wherein the thermoplastic elastomer comprises an elastomer chosen from a thermoplastic polyurea elastomer, a thermoplastic polyamide elastomer, a thermoplastic polyester elastomer, a thermoplastic block copolymer of ethylene and an alpha-olefin having 4 to 8 carbons, or a thermoplastic styrene block copolymer elastomer. 
     
     
         34 . The polymeric mixture of  claim 33 , wherein the thermoplastic polyamide elastomer comprises a thermoplastic polyether block polyamide copolymer. 
     
     
         35 . The polymeric mixture of  claim 29 , wherein the semi-crystalline polymer comprises the copolymer of ethylene with at least one vinyl monomer. 
     
     
         36 . The polymeric mixture of  claim 35 , wherein the copolymer of ethylene with at least one vinyl monomer comprises a copolymer chosen from an ethylene-vinyl acetate copolymer, an ethylene-vinyl alcohol copolymer, an ethylene-vinyl chloride copolymer, or any combination thereof. 
     
     
         37 . The polymeric mixture of  claim 36 , wherein the semi-crystalline polymer comprises the ethylene-vinyl alcohol copolymer. 
     
     
         38 . The polymeric mixture of  claim 37 , wherein the polymeric mixture comprises from 0.5 weight percent to 20 weight percent of the ethylene-vinyl alcohol copolymer. 
     
     
         39 . The polymeric mixture of  claim 37 , wherein the ethylene-vinyl alcohol copolymer has a ratio of ethylene monomer units to vinyl alcohol monomer units of from 20 mole percent to 45 mole percent. 
     
     
         40 . The polymeric mixture of  claim 29 , wherein the semi-crystalline polymer comprises an ethylene-vinyl alcohol copolymer, and the thermoplastic elastomer comprises a thermoplastic polyurethane elastomer. 
     
     
         41 . The polymeric mixture of  claim 29 , wherein the cooling step comprises forming the polymer melt into an article in a shape chosen from a pellet, a bead, a particle, a tape, a ribbon, a rope, a film, a strand, or a fiber. 
     
     
         42 . The polymeric mixture of  claim 29 , wherein the polymer melt is formed in an extruder, then extruded and pelletized during the cooling step 
     
     
         43 . The polymeric mixture of  claim 29 , wherein the semi-crystalline polymer comprises from 1 weight percent to 15 weight percent of total polymer weight of the polymeric mixture, based on total polymer weight of the polymeric mixture. 
     
     
         44 . The polymeric mixture of  claim 29 , wherein the semi-crystalline polymer comprises from 1 weight percent to 10 weight percent of total polymer weight of the polymeric mixture. 
     
     
         45 . The polymeric mixture of  claim 29 , wherein the method further comprises impregnating the polymeric mixture with a gas or supercritical blowing agent. 
     
     
         46 . The polymeric mixture of  claim 29 , wherein the molten mixture further comprises a gaseous or supercritical blowing agent incorporated into the molten mixture under pressure. 
     
     
         47 . The polymeric mixture of  claim 46 , wherein the blowing agent comprises carbon dioxide in gaseous or supercritical state. 
     
     
         48 . The polymeric mixture of  claim 46 , wherein the pressure is released during the cooling step, thereby foaming the polymeric mixture.