Method of toughening thermoplastic polymers and thermoplastic compositions produced thereby

Abstract

A method of forming a toughened article from a blend of a thermoplastic polymer and a comb copolymer is disclosed, along with the toughened article produced thereby. Compositions such as solids blends and melt blends, including a thermoplastic polymer and a comb copolymer, are also disclosed.

We claim:  
     
         1 . A method of forming a toughened article comprising the steps of: 
 (a) forming a solids blend comprising a thermoplastic polymer and a comb copolymer;    (b) heating and mixing said solids blend to form a melt blend; and    (c) shaping said melt blend to form an article; 
 wherein said comb copolymer comprises: 
 a backbone; and  
 as polymerized units, at least one macromonomer comprising a graft segment; and  
 
 wherein said macromonomer is a macromonomer produced by aqueous emulsion polymerization.  
   
     
     
         2 . The method of  claim 1 , further comprising the step: 
 (d) cooling said article to room temperature.    
     
     
         3 . The method of  claim 1 , wherein said comb copolymer is present in an amount sufficient that said article has an impact resistance energy increased at least 15 percent compared to a second article formed identically, absent said comb copolymer.  
     
     
         4 . The method of  claim 1 , wherein said thermoplastic polymer is a polymer selected from the group consisting of poly(vinyl halide), ABS terpolymer, poly(styrene-acrylonitrile), poly(styrene-acrylonitrile-acrylate), polyaromatics, poly(vinyl acetate), poly(vinyl methyl ether), chlorinated polyethylene, phenoxy(polyhydroxypropylether of bisphenol A), poly(methyl methacrylate), poly(styrene-maleic anhydride), poly(ethylene-vinyl acetate), polyesters, polyamides, polyacetal, polyurethane, polyolefins, polycarbonate, and combinations thereof.  
     
     
         5 . The method of  claim 1 , wherein said thermoplastic polymer is poly(vinyl chloride).  
     
     
         6 . The method of  claim 1 , wherein said backbone is immiscible with said thermoplastic polymer.  
     
     
         7 . The method of  claim 1 , wherein said graft segment has a degree of polymerization of 10 to 1,000.  
     
     
         8 . The method of  claim 1 , wherein said graft segment and said backbone are in a weight ratio of 10:90 to 60:40.  
     
     
         9 . A method of forming a toughened article wherein said method comprises the steps of: 
 (A) forming a macromonomer aqueous emulsion comprising a plurality of water-insoluble particles of macromonomer, wherein: 
 (i) said macromonomer comprises polymerized units of at least one first ethylenically unsaturated monomer;  
 (ii) said macromonomer is produced by aqueous emulsion polymerization; and  
 (iii) said macromonomer further has: 
 (a) a degree of polymerization of from 10 to 1000; and  
 (b) at least one terminal ethylenically unsaturated group;  
 
   (B) forming a monomer composition comprising at least one second ethylenically unsaturated monomer;    (C) combining at least a portion of said macromonomer aqueous emulsion and at least a portion of said monomer composition to form a polymerization reaction mixture;    (D) polymerizing said macromonomer with said second ethylenically unsaturated monomer in the presence of an initiator to produce said plurality of comb copolymer particles;    (E) isolating said comb copolymer particles to form a solid comb copolymer;    (F) forming a solids blend comprising a thermoplastic polymer and said solid comb copolymer;    (G) heating and mixing said solids blend to form a melt blend; and    (H) shaping said melt blend to form said article.    
     
     
         10 . The method of  claim 9 , further comprising the step: 
 (I) cooling said article to room temperature.    
     
     
         11 . The method of  claim 9 , wherein said comb copolymer is present in an amount sufficient that said article has an impact resistance energy increased at least 15 percent compared to a second article formed identically, absent said comb copolymer.  
     
     
         12 . The method of  claim 9 , wherein said thermoplastic polymer is a polymer selected from the group consisting of poly(vinyl halide), ABS terpolymer, poly(styrene-acrylonitrile), poly(styrene-acrylonitrile-acrylate), polyaromatics, poly(vinyl acetate), poly(vinyl methyl ether), chlorinated polyethylene, phenoxy(polyhydroxypropylether of bisphenol A), poly(methyl methacrylate), poly(styrene-maleic anhydride), poly(ethylene-vinyl acetate), polyesters, polyamides, polyacetal, polyurethane, polyolefins, polycarbonate, and combinations thereof.  
     
     
         13 . The method of  claim 9 , wherein said thermoplastic polymer is poly(vinyl chloride).  
     
     
         14 . The method of  claim 9 , wherein said backbone is immiscible with said thermoplastic polymer.  
     
     
         15 . The method of  claim 9 , wherein said graft segment is miscible with said thermoplastic polymer.  
     
     
         16 . The method of  claim 9 , wherein said graft segment has a degree of polymerization of 10 to 1,000.  
     
     
         17 . The method of  claim 9 , wherein said backbone has a glass transition temperature of −80° C. to 0° C.  
     
     
         18 . The method of  claim 9 , wherein said graft segment has a glass transition temperature of 50° C. to 180° C.  
     
     
         19 . The method of  claim 9 , wherein said graft segment and said backbone are in a weight ratio of 10:90 to 60:40.  
     
     
         20 . The method of  claim 9 , wherein said comb copolymer is present at 2 to 40 parts by weight per 100 parts by weight of said thermoplastic polymer.