Modified fibers for use in the formation of thermoplastic fiber-reinforced composite articles and process

Abstract

A surface-modified fibrous material is provided for incorporation in a thermoplastic matrix to form a fiber-reinforced composite article. Good binding between the fibrous material and the thermoplastic matrix is achieved through the presence of finely roughened surfaces on the fibers of nanoparticles of an inorganic material. Such nanoparticles are provided from an alkaline aqueous size composition containing the nanoparticles dispersed therein (as described). The fibrous material may be provided in continuous or discontinuous form. In a preferred embodiment glass fibers are initially provided in continuous form followed by cutting into discontinuous lengths and drying with the retention of the nanoparticles on the surfaces of the fibers. The surface-roughened fibrous material is incorporated in a thermoplastic matrix as fibrous reinforcement with the application of heat whereby the thermoplastic matrix is rendered melt processable. In preferred embodiments injection or compression molding is utilized. Improved long-fiber thermoplastics also may be formed to advantage.

We claim: 
     
         1 . Surface-roughened glass fibers comprising:
 glass fibers;   nanoparticles attached to the glass fibers, wherein the nanoparticles provide a roughened surface to the glass fibers;   a combination of silane compounds that include:
 (i) at least one reactive silane; and 
 (ii) at least one non-reactive silane, and 
   a polymeric film former.   
     
     
         2 . The surface-roughened glass fibers of  claim 1 , wherein the glass fibers are chosen from one or more of E-glass, C-glass, A-glass, AR-glass, D-glass, R-glass, and S-glass. 
     
     
         3 . The surface-roughened glass fibers of  claim 1 , wherein the glass fibers have a diameter ranging from about 2 μm to about 50 μm. 
     
     
         4 . The surface-roughened glass fibers of  claim 1 , wherein the glass fibers have a diameter ranging from about 7 μm to about 30 μm. 
     
     
         5 . The surface-roughened glass fibers of  claim 1 , wherein the nanoparticles comprise an inorganic material. 
     
     
         6 . The surface-roughened glass fibers of  claim 5 , wherein the inorganic material is chosen from one or more of silica, clay, glass, metals, metal oxide, aluminum polyphosphate, ferrite, and nanodiamonds. 
     
     
         7 . The surface-roughened glass fibers of  claim 6 , wherein the metal oxide is chosen from one or more of titanium dioxide, zinc oxide, barium oxide, and cerium gadolinium oxide. 
     
     
         8 . The surface-roughened glass fibers of  claim 1 , wherein the nanoparticles comprise silica. 
     
     
         9 . The surface-roughened glass fibers of  claim 1 , wherein the nanoparticles have an average particle size ranging from about 3 nm to about 40 nm. 
     
     
         10 . The surface-roughened glass fibers of  claim 9 , wherein the nanoparticles have an average particle size ranging from about 3 nm to about 10 nm. 
     
     
         11 . The surface-roughened glass fibers of  claim 1 , wherein the at least one reactive silane is chosen from 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyl-methyldimethoxysilane, (3-glycidoxypropyl) trimethoxysilane, 2-(3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-isocyanotopropyltriethoxysilane, vinyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, (3-aminopropyl)methyldiethoxysilane, 3-glycidopropyltriethoxysilane, vinyltriacetoxysilane, mercaptopropyltriethoxysilane, 4-amino-3,3-dimethylbutyltriethoxysilane, and N-butyl-3-aminopropyltrimethoxysilane. 
     
     
         12 . The surface-roughened glass fibers of  claim 1 , wherein the at least one non-reactive silane is chosen from methyltrimethoxysilane, propyltriethoxysilane, propyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, iso-butyltriethoxysilane, octyltriethoxysilane, hexadecyltriethoxysilane, and 1,2-bis(trimethoxysilyl)decane. 
     
     
         13 . The surface-roughened glass fibers of  claim 1 , wherein the polymeric film former is chosen from a non-ionic film former, a cationic film former, and an anionic film former. 
     
     
         14 . The surface-roughened glass fibers for  claim 1 , wherein the polymeric film former is chosen from a polyethylene, a polypropylene, a urethane, and an epoxy. 
     
     
         15 . The surface-roughened glass fibers of  claim 1 , wherein the polymeric film former comprises a polypropylene grafted with maleic anhydride. 
     
     
         16 . A glass-fiber reinforced composite material comprising:
 surface-roughened glass fibers that include:
 glass fibers; 
 nanoparticles attached to the glass fibers, wherein the nanoparticles provide a roughened surface to the glass fibers; 
 a combination of silane compounds that include:
 (i) at least one reactive silane; and 
 (ii) at least one non-reactive silane, and 
 
 a polymeric film former; and 
   a thermoplastic polymer matrix.   
     
     
         17 . The glass-fiber reinforced composite material of  claim 16 , wherein the thermoplastic polymer matrix is chosen from at least one of a polyolefin, a polyester, a polyamide, a polycarbonate, a polyether, a liquid crystal polymer, a polyethersulfone, a polyphenylene oxide, a polyphenylene sulfide, a polybenzimidazole, and a thermoplastic polyurethane. 
     
     
         18 . The glass-fiber reinforced composite material of  claim 17 , wherein the polyolefin is chosen from at least one of polypropylene and polyethylene. 
     
     
         19 . The glass-fiber reinforced composite material of  claim 17 , wherein the polyester is chosen from at least one of polyethylene terephthalate and polybutylene terephthalate. 
     
     
         20 . The glass-fiber reinforced composite material of  claim 17 , wherein the polyamide is chosen from nylon 6 and nylon 6,6. 
     
     
         21 . The glass-fiber reinforced composite material of  claim 16 , wherein the thermoplastic polymer matrix is chosen from at least one polymer of a styrene, a styrene-maleic anhydride, a styrene-maleic acid, a acrylonitrile-butadiene-styrene, a styrene acrylonitrile, a polyetheretherketone, a thermoplastic polyurethane, and an acetonitrile. 
     
     
         22 . The glass-fiber reinforced composite material of  claim 16 , wherein the thermoplastic polymer matrix comprises a polypropylene polymer with a melt flow index between 1 and 100. 
     
     
         23 . The glass-fiber reinforced composite material of  claim 16 , wherein the glass-reinforced composite material comprises pellets that are suitable for melt processing. 
     
     
         24 . A glass-fiber reinforced composite article comprising:
 surface-roughened glass fibers that include:
 glass fibers; 
 nanoparticles attached to the glass fibers, wherein the nanoparticles provide a roughened surface to the glass fibers; 
 a combination of silane compounds that include:
 (i) at least one reactive silane; and 
 (ii) at least one non-reactive silane, and 
 
 a polymeric film former; and 
   a thermoplastic polymer matrix,   wherein the article has a Notched Izod impact strength that is greater than a comparative article formed from glass fibers that lack the nanoparticles.   
     
     
         25 . The glass-fiber reinforced composite article of  claim 24 , wherein the article is an injection molded article.