Primer compositions for injection molding

Abstract

A curable primer composition comprising: (a) a curable component such as methacrylate; (b) a cure initiating component; and (c) a polymer material selected from the group consisting of: (i) block polymers represented by S-A-S where S is polystyrene and A stands for a polymer or copolymer formed from one or more of ethylene, propylene, butylene, and styrene, which are optionally substituted with carboxylic acid or maleic anhydride; provided that when A comprises styrene then A is a copolymer of styrene with at least one of ethylene, propylene and butylene, and is optionally substituted with carboxylic acid or maleic anhydride; and (ii) polystyrene-poly(ethylene-propylene) (“SEP”); and (iii) any combination of said polymer materials. The composition is applied to a part then photocured. It is dry to touch. Thereafter a thermoplastic material such as a polyolefin is overmolded (e.g. injection molded) over the applied composition. It enhances bond strength of the polyolefin to the part.

1 . A curable primer composition comprising:
 (a) a curable component;   (b) a cure initiating component; and   (c) a polymer material selected from the group consisting of:
 (i) block polymers represented by S-A-S wherein S is polystyrene and A stands for a polymer or copolymer formed from one or more of ethylene, propylene, butylene and styrene, which are optionally substituted with carboxylic acid or maleic anhydride; provided that when A comprises styrene then A is a copolymer of styrene with at least one of ethylene, propylene and butylene, and is optionally substituted with carboxylic acid or maleic anhydride; and 
 (ii) polystyrene-poly(ethylene-propylene) (“SEP”); and 
 (iii) any combination of said polymer materials. 
   
     
     
         2 . A curable composition according to  claim 1  wherein the polymer material is selected from the group consisting of block polymers represented by S-A-S where S is polystyrene and A stands for a polymer or copolymer formed from one or more of ethylene, propylene, butylene and styrene which are optionally substituted with carboxylic acid or maleic anhydride;
 provided that when A comprises styrene then A is a copolymer of styrene with at least one of ethylene, propylene and butylene, and is optionally substituted with carboxylic acid or maleic anhydride; 
 and any combination of said polymer materials. 
 
     
     
         3 . A curable composition according to  claim 1  wherein A is formed from one or more of ethylene, propylene, butylene and styrene, provided that A is not formed from styrene alone. 
     
     
         4 . A curable composition according to  claim 1  wherein A is formed from at least two of ethylene, propylene, butylene and styrene. 
     
     
         5 . A curable composition according to  claim 1  wherein A is formed from at least three of ethylene, propylene, butylene and styrene. 
     
     
         6 . A curable composition according to  claim 1  wherein the material S-A-S is selected from:
 (a) polystyrene-poly(ethylene-propylene)-polystyrene (“SEPS”); 
 (b) polystyrene-poly(ethylene-butylene)-polystyrene (“SEBS”); and 
 (c) polystyrene-poly(ethylene-butylene-styrene)-polystyrene (“S(EBS)S”). 
 
     
     
         7 . A curable composition according to  claim 1  wherein A is substituted with carboxylic acid groups and/or maleic anhydride groups. 
     
     
         8 . A curable composition according to  claim 1  wherein A is substituted with maleic anhydride groups. 
     
     
         9 . A curable composition according to  claim 1  wherein the material S-A-S is at least one of
 (a) polystyrene-poly(ethylene-butylene)-polystyrene (“SEBS”); and 
 (b) polystyrene-poly(ethylene-butylene-styrene)-polystyrene (“S(EBS)S”). 
 
     
     
         10 . A curable composition according to  claim 1  wherein the material S-A-S is at least one of
 (a) polystyrene-poly(ethylene-butylene)-polystyrene (“SEBS”); and 
 (b) polystyrene-poly(ethylene-butylene-styrene)-polystyrene (“S(EBS)S”); 
 optionally substituted with carboxylic acid or maleic anhydride. 
 
     
     
         11 . A curable composition according to  claim 1  wherein the material S-A-S is at least one of
 (a) polystyrene-poly(ethylene-butylene)-polystyrene (“SEBS”); and 
 (b) polystyrene-poly(ethylene-butylene-styrene)-polystyrene (“S(EBS)S”); 
 substituted with maleic anhydride. 
 
     
     
         12 . A curable composition according to  claim 1  wherein the material S-A-S is at least one of:
 (a) polystyrene-poly(ethylene-propylene)-polystyrene (“SEPS”); 
 (b) polystyrene-poly(ethylene-butylene)-polystyrene (“SEBS”); 
 (c) polystyrene-poly(ethylene-butylene-styrene)-polystyrene (“S(EBS)S”); and 
 (d) polystyrene-poly(ethylene-ethylene/propylene)-polystyrene (“SEEPS”). 
 
     
     
         13 . A curable composition according to  claim 1  wherein the material S-A-S is at least one of:
 (a) polystyrene-poly(ethylene-propylene)-polystyrene (“SEPS”); 
 (b) polystyrene-poly(ethylene-butylene)-polystyrene (“SEBS”); and 
 (c) polystyrene-poly(ethylene-butylene-styrene)-polystyrene (“S(EBS)S”). 
 
     
     
         14 . A curable composition according to  claim 1  wherein the polymer material selected from the group consisting of:
 (i) block polymers represented by S-A-S wherein S is polystyrene and A stands for a polymer or copolymer formed from one or more of ethylene, propylene, butylene and styrene, which are optionally substituted with carboxylic acid or maleic anhydride; provided that when A comprises styrene then A is a copolymer of styrene with at least one of ethylene, propylene and butylene, and is optionally substituted with carboxylic acid or maleic anhydride; 
 (ii) and polystyrene-poly(ethylene-propylene) (“SEP”); and 
 (iii) any combination of said polymer materials; 
 comprises from about 10 to about 70 weight percent styrene based on the total weight of polymer material. 
 
     
     
         15 . A curable composition according to  claim 1  wherein the curable component is a (meth)acrylate monomer component. 
     
     
         16 . A curable composition according to  claim 1  wherein the cure initiating component is a photoinitiator component. 
     
     
         17 . A curable composition according to  claim 1  wherein A is substituted with carboxylic acid groups. 
     
     
         18 . A curable composition according to  claim 1  wherein, in a B stage cure product of the composition, the material S-A-S is present in an amount from about 5% to about 80% based on the total weight of the composition, for example from about 30% to about 60% by weight based on the total weight of the composition. 
     
     
         19 . A curable composition according to  claim 1  wherein the material S-A-S has a Shore A hardness of 20 to 100. 
     
     
         20 . A combination comprising:
 (a) the composition according to  claim 1 ;   (b) a thermoplastic.   
     
     
         21 . A combination comprising:
 (a) an article having coated as a layer on at least a surface thereof a B-staged version of the composition of  claim 1 ;   (b) a thermoplastic, for example polyolefin, plastic in contact with the B-staged version of the composition.   
     
     
         22 . A process for forming an injection molding about an article, comprising the steps of
 (a) disposing into an injection molding cavity an article about which a thermoplastic, for example polyolefin, plastic material is to be molded into a shape; and   (a) Injecting, into the injection molding cavity in which is disposed the article, the thermoplastic material at a temperature and pressure to permit the material to flow around and about the article in the mold and maintaining the mold under a temperature and pressure appropriate to permit the thermoplastic material to solidify,
 wherein prior to disposition of the article, the article is primed with the composition of  claim 1  and exposed to radiation in the electromagnetic spectrum appropriate to cure the composition. 
   
     
     
         23 . An injection molded article formed form the process of  claim 22 . 
     
     
         24 . The process of  claim 22 , wherein the article is constructed from glass. 
     
     
         25 . The process of  claim 22 , wherein the article is constructed from aluminium. 
     
     
         26 . The process of  claim 22 , wherein the article is constructed from anodized aluminium.