System for producing a fully impregnated thermoplastic prepreg

Abstract

A thermoplastic prepreg includes a mat, web, or fabric of fibers and hollow glass microspheres that are positioned atop the mat, web, or fabric of fibers or dispersed therein. The thermoplastic prepreg also includes a thermoplastic polymer that is fully impregnated through the mat, web, or fabric of fibers and the hollow glass microspheres so that the thermoplastic prepreg has a void content of less than 3% by volume of the thermoplastic prepreg. The thermoplastic material is polymerized monomers and oligomers in which greater than 90% by weight of the monomers or oligomers react to form the thermoplastic material.

What is claimed is: 
     
         1 . A thermoplastic prepreg comprising:
 a first layer composed of a fiber mat, web, or fabric;   a second layer composed of a fiber mat, web, or fabric;   a third layer positioned between the first layer and the second layer, the third layer including a lightweight filler material having a density of between 0.1 and 1.0 g/cm 3 ; and   a thermoplastic polymer that is fully impregnated through the fiber mat, web, or fabric of the first layer, the fiber mat, web, or fabric of the second layer, and the lightweight filler material of the third layer, the thermoplastic polymer being formed via in situ polymerization of monomers and oligomers in which greater than 90% of the monomers or oligomers react to form the thermoplastic polymer;   wherein:
 the thermoplastic prepreg includes 5 to 95 weight percent of the thermoplastic polymer; and 
 the thermoplastic prepreg includes between 1 and 30 weight percent of the lightweight filler material. 
   
     
     
         2 . The thermoplastic prepreg of  claim 1 , wherein the lightweight filler material comprises hollow glass microspheres or perlite. 
     
     
         3 . The thermoplastic prepreg of  claim 1 , wherein the first layer and/or the second layer includes the lightweight filler material dispersed within the respective fiber mat, web, or fabric. 
     
     
         4 . The thermoplastic prepreg of  claim 1 , wherein the third layer includes a combination of the lightweight filler material and fibers. 
     
     
         5 . The thermoplastic prepreg of  claim 1 , wherein the lightweight filler material includes a coating that increases an interfacial strength between the lightweight filler material and thermoplastic polymer. 
     
     
         6 . The thermoplastic prepreg of  claim 1 , wherein a density of the thermoplastic prepreg is less than 1.8 g/cm 3 . 
     
     
         7 . The thermoplastic prepreg of  claim 1 , wherein the thermoplastic prepreg includes between 3 and 10 weight percent of the lightweight filler material. 
     
     
         8 . The thermoplastic prepreg of  claim 1 , wherein the fiber mat, web, or fabric of the first layer is different than the fiber mat, web, or fabric of the second layer. 
     
     
         9 . The thermoplastic prepreg of  claim 1 , wherein a thickness of the first layer is different than a thickness of the second layer. 
     
     
         10 . The thermoplastic prepreg of  claim 1 , wherein the thermoplastic prepreg includes multiple layers of the lightweight filler material, and wherein the multiple layers of lightweight filler material are separated by a layer of the fiber mat, web, or fabric. 
     
     
         11 . The thermoplastic prepreg of  claim 1 , wherein the thermoplastic polymer comprises nylon, polybutylene terephthalate (PBT), polymethyl methacrylate (PMMA), or thermoplastic polyurethane (TPU). 
     
     
         12 . The thermoplastic prepreg of  claim 1 , wherein the thermoplastic prepreg has a void content of less than 5%. 
     
     
         13 . A thermoplastic prepreg comprising:
 a first layer including a first fiber mat, web, or fabric and a thermoplastic polymer impregnated through the first fiber mat, web, or fabric;   a second layer including a second fiber mat, web, or fabric and a thermoplastic polymer impregnated through the second fiber mat, web, or fabric; and   a third layer positioned between the first layer and the second layer, the third layer including a lightweight filler material having a density of between 0.1 and 1.0 g/cm 3  and a thermoplastic polymer impregnated through the lightweight filler material; wherein:   the thermoplastic polymer of the first layer, second layer, and third layer is formed via in situ polymerization of monomers and oligomers in which greater than 90% of the monomers or oligomers are polymerized; and   the thermoplastic prepreg includes between 1 and 30 weight percent of the lightweight filler material.   
     
     
         14 . The thermoplastic prepreg of  claim 13 , wherein the lightweight filler material comprises hollow glass microspheres or perlite. 
     
     
         15 . The thermoplastic prepreg of  claim 13 , wherein the first layer includes the lightweight filler material dispersed within the first fiber mat, web, or fabric and/or the second layer includes the lightweight filler material dispersed within the second respective fiber mat, web, or fabric. 
     
     
         16 . The thermoplastic prepreg of  claim 13 , wherein the third layer includes a combination of the lightweight filler material and fibers. 
     
     
         17 . The thermoplastic prepreg of  claim 13 , wherein the lightweight filler material includes a coating that increases an interfacial strength between the lightweight filler material and thermoplastic polymer. 
     
     
         18 . The thermoplastic prepreg of  claim 13 , wherein a density of the thermoplastic prepreg is less than 1.8 g/cm3. 
     
     
         19 . The thermoplastic prepreg of  claim 13 , wherein the thermoplastic prepreg includes between 3 and 10 weight percent of the lightweight filler material. 
     
     
         20 . The thermoplastic prepreg of  claim 13 , wherein the first fiber mat, web, or fabric is different than the second fiber mat, web, or fabric. 
     
     
         21 . The thermoplastic prepreg of  claim 13 , wherein a thickness of the first layer is different than a thickness of the second layer. 
     
     
         22 . The thermoplastic prepreg of  claim 13 , wherein the thermoplastic prepreg includes multiple layers of the lightweight filler material, and wherein the multiple layers of lightweight filler material are separated by a fiber mat, web, or fabric layer. 
     
     
         23 . The thermoplastic prepreg of  claim 13 , wherein the thermoplastic polymer comprises nylon, polybutylene terephthalate (PBT), polymethyl methacrylate (PMMA), or thermoplastic polyurethane (TPU). 
     
     
         24 . The thermoplastic prepreg of  claim 13 , wherein the thermoplastic prepreg has a void content of less than 5%.