Composites containing crosslinkable thermoplastic and TPV show layer

Abstract

Methods for forming a composite for use as a vehicle weather strip and the products formed thereby are disclosed in which a main body member is formed from an elastomer polymer and an abrasion resistant decorative layer including a blend of a crosslinkable thermoplastic polyolefin and a thermoplastic vulcanizate is applied thereon. The crosslinkable thermoplastic polyolefin preferably includes a crosslinkable olefin homopolymer. The olefin homopolymer preferably contains grafted silane functional groups to allow the material to be crosslinked in the presence of moisture. The abrasion resistant decorative layer may be extruded or otherwise applied onto the main body either prior to or after the main body member is cured and either prior to or after the crosslinkable polyolefin of the abrasion resistant decorative layer is crosslinked. The material of the abrasion resistant decorative layer may be extruded into sheet form and laminated onto the main body member.

1 . A method for forming a composite suitable for use as a vehicle weather strip, the method comprising the steps of: 
 providing an elastomer polymer;    forming a weather strip main body member from said elastomer polymer;    providing a blend of a crosslinkable polyolefin and a thermoplastic vulcanizate;    forming an abrasion resistant decorative layer from said blend;    contacting said abrasion resistant decorative layer with said main body member; and    at least partially crosslinking the crosslinkable thermoplastic polyolefin of the blend, thereby forming said composite extrusion.    
     
     
         2 . The method according to  claim 1 , wherein the step of providing said blend is performed by providing a blend of a moisture crosslinkable olefin homopolymer and a thermoplastic vulcanizate comprising a crosslinked elastomer and a polyolefin, and further wherein the step of at least partially crosslinking said thermoplastic polyolefin is performed by immersing said abrasion resistant decorative layer in a water or steam bath.  
     
     
         3 . The method according to  claim 2 , wherein said moisture crosslinkable olefin homopolymer is a silane grafted polyethylene.  
     
     
         4 . The method according to  claim 2 , wherein said blend comprises from about 75% to about 87% by weight of said TPV and from about 9% to about 15% by weight of said crosslinkable polyolefin.  
     
     
         5 . The method according to  claim 1 , wherein said elastomer polymer is a thermoset elastomer rubber.  
     
     
         6 . The method according to  claim 5 , wherein said thermoset elastomer rubber is an EPDM rubber.  
     
     
         7 . The method according to  claim 5 , further comprising the step of at least partially curing said elastomer polymer of said main body member.  
     
     
         8 . The method according to  claim 1 , wherein the steps of forming a weather strip main body member is performed by extruding said elastomer polymer and the step of forming an abrasion resistant decorative layer is performed by extruding said blend.  
     
     
         9 . The method according to  claim 8 , wherein the step of extruding said main body member is performed utilizing an extrusion temperature of about 110° C.  
     
     
         10 . The method according to  claim 8 , wherein the step of extruding said abrasion resistant decorative layer is performed utilizing an extrusion temperature of from about 200° C. to about 260° C.  
     
     
         11 . The method according to  claim 7 , wherein the step of at least partially curing said elastomer polymer is performed utilizing a temperature of from about 180° C. to about 270° C.  
     
     
         12 . The method according to  claim 7 , wherein the step of contacting said abrasion resistant decorative layer with said main body member is performed after said elastomer polymer is at least partially cured.  
     
     
         13 . The method according to  claim 8 , wherein the steps of extruding said elastomer polymer and extruding said blend are performed by simultaneously extruding said elastomer polymer and said blend through a common extrusion die.  
     
     
         14 . The method according to  claim 13 , further comprising the step of at least partially curing said elastomer polymer, and further wherein the step of at least partially crosslinking said crosslinkable thermoplastic polyolefin of said abrasion resistant decorative layer and the step of at least partially curing said elastomer polymer of said main body member are performed subsequent to the step of simultaneously extruding said elastomer polymer and blend through a common extrusion die.  
     
     
         15 . The method according to  claim 1 , wherein the step of forming said decorative layer is performed by extruding said blend as a sheet member.  
     
     
         16 . The method according to  claim 15 , further comprising a lamination step wherein said sheet member is laminated to said main body member by use of an embossing wheel.  
     
     
         17 . The method according to  claim 1 , wherein the thickness of said abrasion resistant decorative layer is from about 0.1 to about 1.5 mm.  
     
     
         18 . The method according to  claim 17 , wherein the thickness of said abrasion resistant decorative layer is about 0.5 mm.  
     
     
         19 . The method according to  claim 1 , wherein said blend further comprises a slip agent.  
     
     
         20 . The method according to  claim 19 , wherein said slip agent is a siloxane slip agent.  
     
     
         21 . The method according to  claim 20 , wherein said siloxane slip agent is present in said blend in an amount of from about 2-5% by weight.  
     
     
         22 . The method according to  claim 19 , wherein said composite has a static coefficient of friction of between 1.2 and 1.6.  
     
     
         23 . The method according to  claim 19 , wherein said composite has a dynamic coefficient of friction of between 1.8 and 2.1.  
     
     
         24 . A method for forming a composite extrusion suitable for use as a vehicle weather strip, the method comprising the steps of: 
 providing a thermoset elastomer rubber;    forming a weather strip main body member from said thermoset elastomer rubber at a temperature about 110° C.;    providing a blend of a thermoplastic polyolefin comprising a crosslinkable olefin homopolymer and a thermoplastic vulcanizate having a shore A hardness of about 30 to about 50;    forming an abrasion resistant decorative layer from said moisture crosslinkable thermoplastic polyolefin at a temperature of about 200° C. to about 260° C. having a static coefficient of friction of from 1.2-1.6;    contacting said abrasion resistant decorative layer with said main body member;    at least partially crosslinking the olefin homopolymer by exposing the abrasion resistant decorative layer to a water or steam bath at a temperature of about 60° C. to about 110° C.; and    at least partially curing said thermoset elastomer rubber by heating said main body member to at least the cure temperature of said thermoset elastomer rubber, thereby forming the composite extrusion.    
     
     
         25 . A wear resistant composite suitable for use as a vehicle weather strip comprising an abrasion resistant decorative layer, wherein said abrasion resistant decorative layer comprises a blend of an at least partially crosslinked polyolefin and a thermoplastic vulcanizate, the abrasion resistant decorative layer bonded to and disposed immediately adjacent an elastomer polymer main body member.  
     
     
         26 . The composite according to  claim 25 , wherein said crosslinked polyolefin is a moisture crosslinkable silane grafted polyethylene.  
     
     
         27 . The composition according to  claim 25 , wherein said wherein said blend comprises from about 75% to about 87% by weight of said TPV and from about 9% to about 15% by weight of said crosslinkable polyolefin.  
     
     
         28 . The composite according to  claim 25 , wherein said elastomer polymer is a thermoset elastomer rubber.  
     
     
         29 . The composite according to  claim 28 , wherein said thermoset elastomer rubber is an EPDM rubber.  
     
     
         30 . The composite according to  claim 25 , wherein said abrasion resistant decorative layer is a sheet member.  
     
     
         31 . The composite according to  claim 30  wherein said sheet member is laminated and bonded to said main body member.  
     
     
         32 . The composite according to  claim 25 , wherein the thickness of said abrasion resistant layer is from about 0.1 to about 1.5 mm.  
     
     
         33 . The composite according to  claim 32 , wherein the thickness of said abrasion resistant layer is about 0.5 mm.  
     
     
         34 . The composite according to  claim 25 , wherein said abrasion resistant decorative layer comprises a slip agent.  
     
     
         35 . The composite according to  claim 25 , wherein said slip agent comprises a polysiloxane.  
     
     
         36 . The composite according to  claim 35 , wherein said layer has a dynamic coefficient of friction of between 1.8 and 2.1.  
     
     
         37 . A wear resistant composite suitable for use as a vehicle weather strip comprising an abrasion resistant decorative layer comprising a blend of a crosslinked thermoplastic polyolefin, a thermoplastic vulcanizate, and a slip agent, bonded to an at least partially cured thermoset elastomer rubber main body member, wherein said abrasion resistant decorative layer has a static coefficient of friction of between 1.2 and 1.6.  
     
     
         38 . A wear resistant composite according to  claim 37 , wherein said slip agent comprises a polysiloxane.