Thermoplastic vulcanizate and its method of production

Abstract

The invention relates to a thermoplastic vulcanizate comprising four components (A, B, C, D), notably: a thermoplastic (A); a substantially non-cross-linked polyethylene (B); an at least partially vulcanized rubber (C); a softener (D); as well as standard blend ingredients (E). The above mixture contains between 5 and 20 % by weight thermoplastic (A), in relation to the sum of the four components (A, B, C, D). The invention also relates to advantageous material parameters and process steps.

1 - 20 . (Canceled)  
     
     
         21 . A method for producing a thermoplastic vulcanizate, comprising: 
 (a) adding unvulcanized rubber and a standard blend ingredient other than cross-linking agent or cross-linking system into an extruder;    (b) melting the unvulcanized rubber and dispersing the standard blend ingredient in the melted unvulcanized rubber;    (c) adding a plasticizer into melted unvulcanized rubber within a first third part of the extruder;    (d) adding a thermoplastic into the melted unvulcanized rubber downstream of the first third part of the extruder; and    (e) adding cross-linking agent or cross-linking system to cause a dynamic vulcanization of the unvulcanized rubber.    
     
     
         22 . The method of  claim 21 , wherein the thermoplastic is selected from the group consisting of polystyrene, polyamide, polyester, polyolefin, or mixtures thereof.  
     
     
         23 . The method of  claim 22 , wherein the thermoplastic is polypropylene homopolymer or a polypropylene copolymer.  
     
     
         24 . The method of  claim 21 , wherein the unvulcanized rubber is selected from the group consisting of natural rubber, butyl rubber, styrene-butadiene rubber, nitrile rubber, ethylene-propylene-diene copolymer (EPDM) rubber or mixtures thereof.  
     
     
         25 . The method of  claim 21 , wherein the plasticizer is a paraffinic oil or a naphthalic oil.  
     
     
         26 . The method of  claim 21 , wherein the cross-linking agent or the cross- linking system includes a phenolic resin.  
     
     
         27 . The method of  claim 26 , wherein the cross-linking system includes tin dichloride.  
     
     
         28 . The method of  claim 21 , wherein the standard blend ingredient is selected from the group consisting of a filler, an anti-aging agent, a UV-absorber, a pigment, a flame-retarding agent, a fluxing agent, an auxiliary processing agent, and mixtures thereof.  
     
     
         29 . The method of  claim 21 , wherein the extruder is a screw extruder.  
     
     
         30 . The method of  claim 29 , wherein the screw extruder is a twin-screw extruder.  
     
     
         31 . The method of  claim 21 , wherein the extruder is a roll extruder.  
     
     
         32 . The method of  claim 21 , wherein step (a) further comprises adding tin dichloride and wherein step (d) comprises adding polyethylene.