Thermoplastic composites with improved thermal and mechanical properties

Abstract

A moldable composite sheet having improved thermal and mechanical property characteristics. In one aspect, the composite sheet may be a porous fiber-reinforced thermoplastic resin comprising discontinuous mineral reinforcing fibers, and one or more skin layer materials. Generally, the composite sheet may have a void content or porosity from about 5% to about 95% by volume of the sheet, an areal weight between about 400 g/m 2 to about 4000 g/m 2 (gsm), a mineral fiber content from about 20% to about 80% by weight, and a thermoplastic resin content from about 20% to about 80% by weight of the composite sheet. The composite sheet can be molded via low pressure processes, such as thermoforming, match metal molding on stops, vacuum forming and pressure forming, to produce durable automotive interior trim parts and construction articles having improved thermal and mechanical properties in addition to other beneficial characteristics.

1 . A fiber reinforced thermoplastic composite material comprising a fiber reinforced thermoplastic core comprising 
 a thermoplastic resin and    discontinuous fibers dispersed within the thermoplastic resin,    wherein, the composite material exhibits improved sag resistance at about the same basis weight or at a reduced basis weight compared to a comparative composite material comprising a glass fiber reinforced thermoplastic core having discontinuous glass fibers dispersed within the thermoplastic core of the comparative composite material.    
     
     
         2 . The composite material of  claim 1 , wherein the fiber content of the thermoplastic core of the composite material is about the same as or less than the fiber content of the thermoplastic core of the comparative composite material.  
     
     
         3 . The composite material of  claim 1 , wherein the sag resistance is at least about 10% greater than the comparative composite material.  
     
     
         4 . The composite material of  claim 1 , wherein the sag resistance is at least about 20% greater than the comparative composite material.  
     
     
         5 . The composite material of  claim 1 , wherein the sag resistance is at least about 25% greater than the comparative composite material.  
     
     
         6 . The composite material of  claim 1 , wherein the basis weight of the composite material is about the same as the comparative composite material.  
     
     
         7 . The composite material of  claim 1 , wherein the basis weight of the composite material is at least about 10% less than the comparative composite material.  
     
     
         8 . The composite material of  claim 1 , wherein the composite material and the comparative composite material are both in sheet form.  
     
     
         9 . The composite material of  claim 1 , wherein the composite material and the comparative composite material differ only in the fiber content or one or more physical characteristics of the fibers dispersed within the respective thermoplastic cores.  
     
     
         10 . The composite material of  claim 9 , wherein the fibers of the composite material comprise mineral fibers and the fiber content of the thermoplastic core of the composite material is about the same as or less than the glass fiber content of the thermoplastic core of the comparative composite material  
     
     
         11 . The composite material of  claim 1 , wherein the composite material further has greater heat insulative characteristics, greater flexural strength, greater flexural modulus, or a combination thereof, compared to the glass fiber reinforced comparative composite material.  
     
     
         12 . The composite material of  claim 1 , wherein the thermoplastic core has a porosity between about 0% to about 95% by volume of the thermoplastic core and an areal density of from about 400 g/m 2  to about 4000 g/m 2 .  
     
     
         13 . The composite material of  claim 12 , wherein the thermoplastic core has a porosity between about 30% to about 80% by volume of the thermoplastic core.  
     
     
         14 . The composite material of  claim 1 , wherein the fiber content is from about 20 wt. % to about 80 wt. % of the thermoplastic core.  
     
     
         15 . The composite material of  claim 1 , wherein the fiber diameter is greater than. about 7 μm.  
     
     
         16 . The composite material of  claim 1 , wherein the fiber length is from about 7 mm to about 50 mm.  
     
     
         17 . The composite material of  claim 1 , wherein the thermoplastic resin is selected from polyolefins, thermoplastic polyolefin blends, polyvinyl polymers, butadiene polymers, acrylic polymers, polyamides, polyesters, polycarbonates, polyestercarbonates, polystyrenes, acrylonitrylstyrene polymers, acrylonitrile-butylacrylate-styrene polymers, polyether imide, polyphenylene ether, polyphenylene oxide, polyphenylenesulphide, polyethers, polyetherketones, polyacetals, polyurethanes, polybenzimidazole, and copolymers or a mixture thereof.  
     
     
         18 . The composite material of  claim 1 , wherein the fibers are selected from glass fibers, carbon fibers, graphite fibers, synthetic organic fibers, inorganic fibers, natural fibers, mineral fibers, metal fibers, metalized inorganic fibers, metalized synthetic fibers, ceramic fibers, or a combination thereof.  
     
     
         19 . The composite material of  claim 18 , wherein the fibers are mineral fibers selected from basalt, mineral wool, wollastonite, alumina silica, or a combination thereof.  
     
     
         20 . The composite material of  claim 1 , further comprising a skin layer selected from films, non-woven scrims, veils, woven fabrics, or a combination thereof.  
     
     
         21 . An article formed from the composite material of  claim 1 .  
     
     
         22 . The article of  claim 21 , in the form of a construction article, tape, or an automobile article selected from a parcel shelf, package tray, headliner, door module, instrument panel topper, side wall panels, cargo liners, front and/or rear pillar trim, or a sunshade.  
     
     
         23 . The composite material of  claim 1 , wherein the thermoplastic core is prepared by a method comprising, 
 adding reinforcing fibers and a thermoplastic resin to an agitated liquid-containing foam to form a dispersed mixture of thermoplastic resin and reinforcing fibers;    depositing the dispersed mixture of reinforcing fibers and thermoplastic resin onto a forming support element;    evacuating the liquid to form a web;    heating the web above the softening temperature of the thermoplastic resin; and    compressing the web to a predetermined thickness to form the thermoplastic core.