Overmolded polyamide composite structures and processes for their preparation

Abstract

Disclosed are overmolded polyamide composites structures and processes for their preparation. The disclosed overmolded composite structures comprise i) a first component having a surface, which surface has at least a portion made of a surface resin composition, and comprising a fibrous material, ii) a second component comprising an overmolding resin composition, adhered to said first component over at least a portion of the surface of said first component. The surface resin composition is selected from polyamide compositions comprising a blend of (A) one or more fully aliphatic polyamides selected from group (I) polyamides having a melting point of less than 230° C., and (B) one or more polyamides selected from group (II) polyamides having a melting point of at least 250° C., and wherein the matrix resin composition is selected from (B) or blends of (A) and (B).

1 . An overmolded composite structure comprising:
 i) a first component having a surface, which surface has at least a portion made of a surface resin composition, and the composite structure comprising a fibrous material selected from the group consisting of: (a) non-woven structures that have random fiber orientation with chopped or continuous fiber in the form of a mat, a needled mat, or a felt; (b) non-woven structures that have aligned fiber orientation in the form of unidirectional fiber strands; (c) multi-axial textiles; and combinations thereof, said fibrous material being impregnated with a matrix resin composition,   ii) a second component comprising an overmolding resin composition, wherein said second component is adhered to said first component over at least a portion of the surface of said first component, and   wherein the surface resin composition is selected from polyamide compositions comprising a blend of (A) one or more fully aliphatic polyamides selected from group (I) polyamides having a melting point of less than 230° C., and (B) one or more fully aliphatic polyamides selected from group (II) polyamides having a melting point of at least 250° C., and wherein the matrix resin composition is independently selected from (B) or independently selected from blends of (A) and (B).   
     
     
         2 . The overmolded composite structure according to  claim 1 , wherein the overmolding resin composition is selected from polyamide compositions comprising a blend of (A) one or more fully aliphatic polyamides selected from group (I) polyamides having a melting point of less than 230° C., and (B) one or more fully aliphatic polyamides selected from group (II) polyamides having a melting point of at least 250° C., or solely from polyamides selected from (B) group (II) polyamides having a melting point of at least 250° C. 
     
     
         3 . The overmolded composite structure according to  claim 1  wherein the fibrous material is selected from the group consisting of glass fibers, carbon fibers, aramid fibers, natural fibers or mixtures thereof. 
     
     
         4 . The overmolded composite structure according to  claim 3 , wherein the fibrous material is glass fibers. 
     
     
         5 . The composite structure of  claim 1  wherein the fibrous material is from 30 volume percent to 60 volume percent of the composite structure. 
     
     
         6 . The composite structure according to  claim 1  further comprising one or more additives selected from the group consisting of heat stabilizers, oxidative stabilizers, reinforcing agents and flame retardants or combination thereof. 
     
     
         7 . The composite structure according to  claim 1  wherein the one or more fully aliphatic polyamides selected from group (I) polyamides is selected form the group consisting of PA 6, PA510, PA512, PA6/66, PA6/610, PA6/612, PA613, PA615, PA6/66/610, PA6/66/612, PA6/66/610/612, PA D6/66, PA1010, PA1012, PA11, PA12, PA612, PA1212. 
     
     
         8 . The composite structure according to  claim 1  wherein the one or more fully aliphatic polyamides selected from group (II) polyamides is selected form the group consisting of PA 66, PA6/66, PA6/66/610, PA6/66/612, PA6/66/610/612, PA D6/66, PA46. 
     
     
         9 . The overmolded composite structure according to  claim 1  wherein the weight ratio of the one or more polyamides selected from group (I) polyamides (A) and the one or more polyamides selected from group (II) polyamides (B) (A:B) of the matrix polyamide composition is between from about 1:99 to about 95:5 
     
     
         10 . The overmolded composite structure according to  claim 1  wherein the weight ratio of the one or more polyamides selected from group (I) polyamides (A) and the one or more polyamides selected from group (II) polyamides (B) (A:B) of the matrix polyamide composition from about 20:80 to about 30:70 and the weight ratio of the one or more polyamides selected from group (I) polyamides (A) and the one or more polyamides selected from group (II) polyamides (B) (A:B) of the surface polyamide composition is from about 40:60 to about 60:40. 
     
     
         11 . The overmolded composite structure according to  claim 1  wherein the matrix resin composition comprises one or more polyamides selected from group (II) polyamides (B) and the weight ratio of the one or more polyamides selected from group (I) polyamides (A) and the one or more polyamides selected from group (II) polyamides (B) (A:B) of the surface polyamide composition is from about 40:60 to about 60:40. 
     
     
         12 . The composite structure according to  claim 1  wherein (A) comprises PA6, PA6/12, PA10/10, solely or in combinations thereof. 
     
     
         13 . The composite structure according to  claim 1  wherein (B) comprises PA66, PA46, solely or in combinations thereof. 
     
     
         14 . The overmolded composite structure according to  claim 1  in the form of a component for automobiles, trucks, commercial airplanes, aerospace, rail, household appliances, computer hardware, hand held devices, recreation and sports, structural component for machines, structural components for buildings, structural components for photovoltaic equipments or structural components for mechanical devices. 
     
     
         15 . A process for making the overmolded composite structure of  claim 1 , said process comprising a step of overmolding a second component comprising an overmolding resin composition on a first component, wherein the first component comprises a fibrous material and has a surface, said surface having at least a portion made of a surface resin composition, and said fibrous material being selected from non-woven structures, textiles, fibrous battings and combinations thereof and said fibrous material being impregnated with a matrix resin composition, said second component being adhered to said first component over at least a portion of the surface of said first component, wherein the surface resin composition is selected from polyamide compositions comprising a blend of (A) one or more fully aliphatic polyamides selected from group (I) polyamides having a melting point of less than 230° C., and (B) one or more fully aliphatic polyamides selected from group (II) polyamides having a melting point of at least 250° C., and wherein the matrix resin composition is independently selected from (B) or independently selected from blends of (A) and (B). 
     
     
         16 . The process according to  claim 15 , further comprising a step of shaping the first component, said step of shaping arising after the step of impregnating but before the step of overmolding. 
     
     
         17 . The process according to  claim 15  wherein the first component is heated before the step of overmolding to soften and partially melt a surface which will form an interface with the overmolding resin composition. 
     
     
         18 . The process according to  claim 15  wherein the first component is not heated prior to the step of overmolding.