Patent Publication Number: US-2020290310-A1

Title: Lightweight reinforced thermoplastic composite articles including bicomponent fibers

Description:
PRIORITY APPLICATION 
     This application is related to, and claims priority to and the benefit of, U.S. Provisional Application No. 62/800,314 filed on Feb. 1, 2019 and U.S. Provisional Application No. 62/874,036 filed on Jul. 15, 2019, the entire disclosure of each of which is hereby incorporated herein by reference. 
    
    
     TECHNOLOGICAL FIELD 
     Certain embodiments are directed to thermoplastic composite articles comprising bicomponent fibers. In some instances, the thermoplastic composite articles with the bicomponent fibers may provide improved performance over thermoplastic composite articles lacking the bicomponent fibers. 
     BACKGROUND 
     Certain automotive and building applications often use thermoplastic based materials in place of conventional steel or metal articles. The use of thermoplastic based materials can create unique considerations not encountered with steel or metal articles. 
     SUMMARY 
     Certain aspects are described herein to illustrate some configurations of thermoplastic composite articles with bicomponent fibers. It will be within the ability of the person having ordinary skill in the art, given the benefit of this disclosure, to produce other configurations of thermoplastic composite articles that include bicomponent fibers. 
     In an aspect, a molded porous composite article comprises a lofted core layer comprising a web formed from reinforcing fibers, bicomponent fibers, a lofting agent and a thermoplastic material, wherein the web comprises a porosity of about 20% to about 80%, and wherein the bicomponent fibers comprise a core-shell arrangement, wherein a shell material of the shell of the core-shell arrangement comprises a melting point that is substantially similar to a melting point of the thermoplastic material, and wherein a core material of the core of the core-shell arrangement comprises a melting point that is at least twenty degrees Celsius higher than the melting point of the thermoplastic material, and wherein the molded porous composite article comprises a peak load of 10 N to about 40 N in the machine direction and a peak load of about 6N to about 30N in the cross direction at a molded thickness of about 2 mm to about 4 mm in both the machine and cross directions as tested by SAE J949_200904. 
     In certain embodiments, the bicomponent fibers comprise a shell comprising a polyolefin and a core comprising a polyester or a polyamide. In other examples, the bicomponent fibers comprise a shell comprising a polyolefin and a core comprising a polyester. In some examples, the polyolefin comprises a polyethylene. In other examples, the polyethylene is linear low density polyethylene. In some embodiments, the polyester comprises polyethylene terephthalate. In other examples, the polyamide comprises nylon. 
     In some instances, the thermoplastic material is polypropylene, the polyolefin of the shell comprises linear low density polyethylene, the lofting agent comprises expandable microspheres and the polyester of the core comprises polyethylene terephthalate. 
     In other instances, the thermoplastic material is polypropylene, the polyolefin of the shell comprises linear low density polyethylene, the lofting agent comprises expandable microspheres and the polyamide of the core comprises nylon. 
     In certain examples, the thermoplastic material comprises polypropylene, the reinforcing fibers comprise glass fibers, the bicomponent fibers comprise a linear low density polyethylene in the shell and a polyester or polyamide in the core, wherein a melting point of the polyester or polyamide in the core is at least twenty degrees Celsius higher than a melting point of the thermoplastic material, wherein the lofting agent comprises expandable microspheres. 
     In some examples, the molded composite article further comprises a stiffness in the machine direction of about 10 N/cm to about 50 N/cm and a stiffness in the cross direction of about 7 N/cm to about 30 N/cm as tested by SAE J949_200904. 
     In other examples, the molded composite article further comprises a flexural strength in the machine direction of about 6 MPa to about 17 MPa and a flexural strength in the cross direction of about 4 MPa to about 11 MPa as tested by SAE J949_200904. 
     In further examples, the molded composite article further comprises a flexural modulus in the machine direction of about 800 MPa to about 2000 MPa and a flexural modulus in the cross direction of about 500 MPa to about 1300 MPa as tested by SAE J949_200904. 
     In certain instances, the molded composite article further comprises a stiffness in the machine direction of about 10 N/cm to about 50 N/cm and a stiffness in the cross direction of about 7 N/cm to about 30 N/cm as tested by SAE J949_200904 and a flexural strength in the machine direction of about 6 MPa to about 17 MPa and a flexural strength in the cross direction of about 4 MPa to about 11 MPa as tested by SAE J949_200904. 
     In some embodiments, the molded composite article further comprises a stiffness in the machine direction of about 10 N/cm to about 50 N/cm and a stiffness in the cross direction of about 7 N/cm to about 30 N/cm as tested by SAE J949_200904 and a flexural modulus in the machine direction of about 800 MPa to about 2000 MPa and a flexural modulus in the cross direction of about 500 MPa to about 1300 MPa as tested by SAE J949_200904. 
     In certain examples, the molded composite article further comprises a flexural strength in the machine direction of about 6 MPa to about 17 MPa and a flexural modulus in the machine direction of about 800 MPa to about 2000 MPa and a flexural modulus in the cross direction of about 500 MPa to about 1300 MPa as tested by SAE J949_200904. 
     In some examples, the molded composite article further comprises a stiffness in the machine direction of about 10 N/cm to about 50 N/cm and a stiffness in the cross direction of about 7 N/cm to about 30 N/cm as tested by SAE J949_200904, a flexural strength in the machine direction of about 6 MPa to about 17 MPa and a flexural strength in the cross direction of about 4 MPa to about 11 MPa as tested by SAE J949_200904, and a flexural modulus in the machine direction of about 800 MPa to about 2000 MPa and a flexural modulus in the cross direction of about 500 MPa to about 1300 MPa as tested by SAE J949_200904. 
     In certain embodiments, the article is configured as an automotive headliner, an automotive interior component, as a cubicle panel or a furniture panel. 
     In another aspect, a molded porous composite article comprises a lofted core layer comprising a web formed from reinforcing fibers, bicomponent fibers, a lofting agent and a thermoplastic material, wherein the web comprises a porosity of about 20% to about 80%, and wherein the bicomponent fibers comprise a core-shell arrangement, wherein a shell material of the shell of the core-shell arrangement comprises a melting point that is substantially similar to a melting point of the thermoplastic material, and wherein a core material of the core of the core-shell arrangement comprises a melting point that is at least twenty degrees Celsius higher than the melting point of the thermoplastic material, and wherein the molded porous composite article comprises a stiffness in the machine direction of about 10 N/cm to about 50 N/cm and a stiffness in the cross direction of about 7 N/cm to about 30 N/cm as tested by SAE J949_200904. 
     In some examples, the molded composite article further comprises a flexural strength in the machine direction of about 6 MPa to about 17 MPa and a flexural strength in the cross direction of about 4 MPa to about 11 MPa as tested by SAE J949_200904. 
     In other examples, the molded composite article further comprises a flexural modulus in the machine direction of about 800 MPa to about 2000 MPa and a flexural modulus in the cross direction of about 500 MPa to about 1300 MPa as tested by SAE J949_200904. 
     In additional examples, the molded composite article further comprises a flexural strength in the machine direction of about 6 MPa to about 17 MPa and a flexural strength in the cross direction of about 4 MPa to about 11 MPa as tested by SAE J949_200904, and a flexural modulus in the machine direction of about 800 MPa to about 2000 MPa and a flexural modulus in the cross direction of about 500 MPa to about 1300 MPa as tested by SAE J949_200904. 
     In another aspect, a molded porous composite article comprises a lofted core layer comprising a web formed from reinforcing fibers, bicomponent fibers, a lofting agent and a thermoplastic material, wherein the web comprises a porosity of about 20% to about 80%, and wherein the bicomponent fibers comprise a core-shell arrangement, wherein a shell material of the shell of the core-shell arrangement comprises a melting point that is substantially similar to a melting point of the thermoplastic material, and wherein a core material of the core of the core-shell arrangement comprises a melting point that is at least twenty degrees Celsius higher than the melting point of the thermoplastic material, and wherein the molded porous composite article comprises a flexural strength in the machine direction of about 6 MPa to about 17 MPa and a flexural strength in the cross direction of about 4 MPa to about 11 MPa as tested by SAE J949_200904. 
     In certain examples, the molded composite article further comprises a flexural modulus in the machine direction of about 800 MPa to about 2000 MPa and a flexural modulus in the cross direction of about 500 MPa to about 1300 MPa as tested by SAE J949_200904. 
     In an additional aspect, a molded porous composite article comprises a lofted core layer comprising a web formed from reinforcing fibers, bicomponent fibers, a lofting agent and a thermoplastic material, wherein the web comprises a porosity of about 20% to about 80%, and wherein the bicomponent fibers comprise a core-shell arrangement, wherein a shell material of the shell of the core-shell arrangement comprises a melting point that is substantially similar to a melting point of the thermoplastic material, and wherein a core material of the core of the core-shell arrangement comprises a melting point that is at least twenty degrees Celsius higher than the melting point of the thermoplastic material, and wherein the molded porous composite article comprises a flexural modulus in the machine direction of about 800 MPa to about 2000 MPa and a flexural modulus in the cross direction of about 500 MPa to about 1300 MPa as tested by SAE J949_200904. 
     Additional aspects, examples, embodiments and configurations are described in more detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE FIGURES 
       Certain aspects, embodiments and examples are described with reference to the accompanying figures in which: 
         FIG. 1  is an illustration of a core-shell fiber arrangement, in accordance with some examples; 
         FIG. 2  is an illustration of a side-by-side fiber arrangement, in accordance with certain embodiments; 
         FIGS. 3A and 3B  are each illustrations of side-by-side fiber arrangements with a shell, in accordance with some examples; 
         FIG. 4  is an illustration of a core layer, in accordance with some examples; 
         FIG. 5  shows a process that can be used to produce a core layer, in accordance with some examples; 
         FIG. 6  shows another process that can be used to produce a core layer, in accordance with certain examples; 
         FIG. 7  is an illustration of an article comprising a core layer and a skin layer, in accordance with some examples; 
         FIG. 8  is an illustration of an article comprising a core layer and two skin layers, in accordance with some examples; 
         FIG. 9  is an illustration of an article comprising a core layer, a skin layer and a decorative layer, in accordance with some examples; 
         FIG. 10  is an illustration of an automotive headliner, in accordance with some examples; 
         FIG. 11  is an illustration of an automotive rear trim piece, in accordance with some examples; 
         FIG. 12  is an illustration of a furniture article, in accordance with some embodiments; 
         FIG. 13  is another illustration of a furniture article, in accordance with some embodiments; 
         FIG. 14  is another illustration of a furniture article, in accordance with some embodiments; 
         FIG. 15  is another illustration of a furniture article, in accordance with some embodiments; 
         FIG. 16  shows a photograph of a molded part produced using a hybrid light weight reinforced thermoplastic sheet; 
         FIG. 17  is a graph showing measured tensile modulus in a machine direction (MD) and cross direction (CD) for several samples; 
         FIG. 18  is a graph showing measured tensile strength in a machine direction (MD) and cross direction (CD) for several samples; 
         FIG. 19A  is a graph comparing peak load in the machine direction for various samples; and 
         FIG. 19B  is a graph comparing peak load in the cross direction for various samples. 
     
    
    
     It will be recognized by the person of ordinary skill in the art that the depictions and layers in the figures are provided merely for illustration purposes. No particular thickness, materials, dimensions of the like are intended to be implied or required unless otherwise described clearly in the description herein in connection with that particular illustration. 
     DETAILED DESCRIPTION 
     Certain examples are described herein of composite articles that include a combination of thermoplastic materials and different fibers to provide improved properties. In some examples, one or more of peak load, stiffness, flexural strength and flexural modulus can be improved. 
     In certain embodiments, the articles produced herein are described in certain instances as light weight reinforced thermoplastic (LWRT) articles. In general, the articles comprise a core layer comprising a web formed from thermoplastic material, reinforcing fibers, bicomponent fibers and optionally a lofting agent. The presence of the combined materials can assist in enhanced properties. 
     In certain configurations, the bicomponent fibers of the core layer may comprise two or more different materials that can be arranged in numerous different ways. For example, the bi-component fibers can be configured as a core-shell arrangement, a side-by-side arrangement or a combination of these arrangements with a shell surrounding a side-by-side arrangement of the fibers. The different fibers can be extruded, co-extruded, drawn or produced in similar manners that are used to produce fibers. In some examples, the produced fiber can be coated in another material to provide the shell around a core fiber. Where more than a single fiber is present in the shell, the fibers can be coaxial, e.g., remain untwisted, or may cross over or be twisted as desired. Referring to  FIG. 1 , an illustration showing a cross-section through a core-shell arrangement of bicomponent fibers is shown. The bicomponent fiber  100  comprises a core material  110  surrounded by a shell material  120 . Each of the components  110 ,  120  may not be a fiber in the true sense, but together the materials of the core  110  and the shell  120  form a fiber. Alternatively, each of the materials  110 ,  120  could be considered a fiber. The shell material  120  need not completely surround the core material  110  or by symmetric. Without wishing to be bound by any particular theory, the shell material  120  is selected so it is compatible with the thermoplastic material, e.g., the thermoplastic resin, used to produce the core layer. For example, a melting point of the shell material  120  can be about the same or the same as a melting point of the thermoplastic material of the core layer. In some examples, the melting points of the shell material  120  and the thermoplastic material may differ by about one to about ten degrees Celsius and the materials can still be considered compatible. 
     In certain embodiments, the core material  110  typically comprises a higher melting point than the shell material  120  and the thermoplastic material. For example, as the core layer is formed, the shell material  120  and the thermoplastic material can be melted or softened to form the web of the core layer. The core material  110  typically remains solid and does not melt of soften to any substantial degree during processing of the materials to form the core layer. 
     In certain examples, a melting point of the core material  110  is at least fifteen degrees Celsius higher than a melting point of the shell material  120  or the melting point of the thermoplastic material. In some examples, a melting point of the core material  110  is at least twenty degrees Celsius higher than a melting point of the shell material  120  or the melting point of the thermoplastic material. In other examples, a melting point of the core material  110  is at least twenty-five degrees Celsius higher than a melting point of the shell material  120  or the melting point of the thermoplastic material. In other examples, a melting point of the core material  110  is at least thirty degrees Celsius higher than a melting point of the shell material  120  or the melting point of the thermoplastic material. In certain examples, a melting point of the core material  110  is at least thirty-five degrees Celsius higher than a melting point of the shell material  120  or the melting point of the thermoplastic material. In certain embodiments, a melting point of the core material  110  is at least forty degrees Celsius higher than a melting point of the shell material  120  or the melting point of the thermoplastic material. In other embodiments, a melting point of the core material  110  is at least forty-five degrees Celsius higher than a melting point of the shell material  120  or the melting point of the thermoplastic material. In other embodiments, a melting point of the core material  110  is at least fifty degrees Celsius higher than a melting point of the shell material  120  or the melting point of the thermoplastic material. 
     In certain configurations, the materials present in the shell  120  and the core  110  are not the same material. For example, the shell material  120  may comprise a polyolefin and the core material  110  may comprise a material with a melting point higher than the melting point of the polyolefin of the shell material  120 . In other instances, the core material  110  may comprise a polyester, a polyamide or a co-polyamide and the shell material  120  may comprise a material with a lower melting point than a melting point of the polyester, a polyamide or a co-polyamide in the core material  110 . In additional examples, the shell material  120  may comprise a polyolefin and the core material  110  may comprise a polyester, a polyamide or a co-polyamide. In some examples, the shell material  120  comprises a polyolefin and the core material  110  comprises a polyester. In other examples, the shell material  120  comprises a polyolefin and the core material  110  comprises a polyamide. In some examples, the shell material  120  comprises a polyolefin and the core material comprises a co-polyamide. 
     In some examples, the polyolefin of the shell material  120  may be polyethylene, polypropylene or other olefinic polymers and co-polymers. In some embodiments, the polyolefin material of the shell  120  may be considered a linear low density polyolefin. For example, the polyolefin material of the shell  120  may be a linear low density polyethylene (LLDPE) or a low density polyethylene (LDPE). While the exact material properties can vary, a linear low density polyethylene may comprise a density of about 0.91 g/cm3 to about 0.94 g/cm3. In some examples, a melting point of the LLDPE or LDPE can be at least fifteen degrees Celsius lower than a melting point of the core material  110 . In certain examples, a melting point of the LLDPE or LDPE can be at least twenty degrees Celsius lower than a melting point of the core material  110 . In other examples, of the LLDPE or LDPE can be at least twenty-five degrees Celsius lower than a melting point of the core material  110 . In certain examples, a melting point of the LLDPE or LDPE can be at least thirty degrees Celsius lower than a melting point of the core material  110 . In other examples, a melting point of the LLDPE or LDPE can be at least thirty-five degrees Celsius lower than a melting point of the core material  110 . In certain examples, a melting point of the LLDPE or LDPE can be at least forty degrees Celsius lower than a melting point of the core material  110 . In other examples, a melting point of the LLDPE or LDPE can be at least forty-five degrees Celsius lower than a melting point of the core material  110 . In some examples, a melting point of the LLDPE or LDPE can be at least fifty degrees Celsius lower than a melting point of the core material  110 . 
     In other examples, the core material  110  may comprise a polyester comprising monomeric units of a terephthalate. For example, the polyester may be polyethylene terephthalate, polybutylene terephthalate or polynaphthalene terephthalate. In certain examples, a melting point of the polyester comprising monomeric units of a terephthalate in the core material  110  may be at least fifteen degrees higher than a melting point of material in the shell material  120 . In some examples, a melting point of the polyester comprising monomeric units of a terephthalate in the core material  110  may be at least twenty degrees higher than a melting point of material in the shell material  120 . In certain examples, a melting point of the polyester comprising monomeric units of a terephthalate in the core material  110  may be at least twenty-five degrees higher than a melting point of material in the shell material  120 . In other examples, a melting point of the polyester comprising monomeric units of a terephthalate in the core material  110  may be at least thirty degrees higher than a melting point of material in the shell material  120 . In certain examples, a melting point of the polyester comprising monomeric units of a terephthalate in the core material  110  may be at least thirty-five degrees higher than a melting point of material in the shell material  120 . In some examples, a melting point of the polyester comprising monomeric units of a terephthalate in the core material  110  may be at least forty degrees higher than a melting point of material in the shell material  120 . In other examples, a melting point of the polyester comprising monomeric units of a terephthalate in the core material  110  may be at least forty-five degrees higher than a melting point of material in the shell material  120 . In additional examples, a melting point of the polyester comprising monomeric units of a terephthalate in the core material  110  may be at least fifty degrees higher than a melting point of material in the shell material  120 . 
     In some embodiments, the core material  110  may comprise a polyamide or a co-polyamide. For example, the core material  110  may comprise nylon, nylon  66 , aramid, polyesteramides, polyetheramides, polyetheresteramides, or other polyamide-containing copolymers. In certain examples, a melting point of the polyamide or co-polyamide in the core material  110  may be at least fifteen degrees higher than a melting point of material in the shell material  120 . In some examples, a melting point of the polyamide or co-polyamide in the core material  110  may be at least twenty degrees higher than a melting point of material in the shell material  120 . In certain examples, a melting point of the polyamide or co-polyamide in the core material  110  may be at least twenty-five degrees higher than a melting point of material in the shell material  120 . In other examples, a melting point of the polyamide or co-polyamide in the core material  110  may be at least thirty degrees higher than a melting point of material in the shell material  120 . In certain examples, a melting point of the polyamide or co-polyamide in the core material  110  may be at least thirty-five degrees higher than a melting point of material in the shell material  120 . In some examples, a melting point of the polyamide or co-polyamide in the core material  110  may be at least forty degrees higher than a melting point of material in the shell material  120 . In other examples, a melting point of the polyamide or co-polyamide in the core material  110  may be at least forty-five degrees higher than a melting point of material in the shell material  120 . In additional examples, a melting point of the polyamide or co-polyamide in the core material  110  may be at least fifty degrees higher than a melting point of material in the shell material  120 . 
     In certain examples, the shell material  120  may comprise a polyethylene, e.g., a LLDPE, and the core material  110  may comprise a polyester or a polyamide. For example, the core material  110  may comprise nylon, polyethylene terephthalate, polybutylene terephthalate, polynaphthalene terephthalate, or combinations thereof. In certain examples, a melting point of the polyester or polyamide in the core material  110  may be at least fifteen degrees higher than a melting point of the polyethylene material in the shell material  120 . In some examples, a melting point of the polyester or polyamide in the core material  110  may be at least twenty degrees higher than a melting point of the polyethylene material in the shell material  120 . In certain examples, a melting point of the polyester or polyamide in the core material  110  may be at least twenty-five degrees higher than a melting point of the polyethylene material in the shell material  120 . In other examples, a melting point of the polyester or polyamide in the core material  110  may be at least thirty degrees higher than a melting point of the polyethylene material in the shell material  120 . In certain examples, a melting point of the polyester or polyamide in the core material  110  may be at least thirty-five degrees higher than a melting point of the polyethylene material in the shell material  120 . In some examples, a melting point of the polyester or polyamide in the core material  110  may be at least forty degrees higher than a melting point of the polyethylene material in the shell material  120 . In other examples, a melting point of the polyester or polyamide in the core material  110  may be at least forty-five degrees higher than a melting point of the polyethylene material in the shell material  120 . In additional examples, a melting point of the polyester or polyamide in the core material  110  may be at least fifty degrees higher than a melting point of the polyethylene material in the shell material  120 . 
     In other instances, the bicomponent fibers present in the LWRT articles may comprise a side-to-side fiber arrangement. Referring to  FIG. 2 , an illustration showing a cross-section through a side-by-side fiber arrangement of bicomponent fibers is shown. The bicomponent fiber  200  comprise a first fiber  210  arranged to the side of a second fiber  220 . The fibers  210 ,  220  can be twisted around each other or may remain untwisted and run generally co-axial with each other throughout the fiber  200 . Without wishing to be bound by any particular theory, a melting point of materials in one of the fibers  210 ,  220  is typically about the same as or the same as a melting point of the thermoplastic material of the core layer. In some examples, the melting points of one of the fibers  210 ,  220  and the thermoplastic material may differ by about one to about ten degrees Celsius and the materials can still be considered compatible. 
     In certain embodiments, the fiber  210  typically comprises a higher melting point than the other fiber  220  and the thermoplastic material. For example, as the core layer is formed, the fiber  220  and the thermoplastic material can be melted or softened to form the web of the core layer. The fiber  210  typically remains solid and does not melt of soften to any substantial degree during processing of the materials to form the core layer. In certain examples, a melting point of the fiber  210  is at least fifteen degrees Celsius higher than a melting point of the fiber  220  or the melting point of the thermoplastic material. In some examples, a melting point of the fiber  210  is at least twenty degrees Celsius higher than a melting point of the fiber  220  or the melting point of the thermoplastic material. In other examples, a melting point of the fiber  210  is at least twenty-five degrees Celsius higher than a melting point of the fiber  220  or the melting point of the thermoplastic material. In other examples, a melting point of the fiber  210  is at least thirty degrees Celsius higher than a melting point of the fiber  220  or the melting point of the thermoplastic material. In certain examples, a melting point of the fiber  210  is at least thirty-five degrees Celsius higher than a melting point of the fiber  220  or the melting point of the thermoplastic material. In certain embodiments, a melting point of the fiber  210  is at least forty degrees Celsius higher than a melting point of the fiber  220  or the melting point of the thermoplastic material. In other embodiments, a melting point of the fiber  210  is at least forty-five degrees Celsius higher than a melting point of the fiber  220  or the melting point of the thermoplastic material. In other embodiments, a melting point of the fiber  210  is at least fifty degrees Celsius higher than a melting point of the fiber  220  or the melting point of the thermoplastic material. 
     In certain configurations, the materials present in the fibers  210 ,  220  are not the same material. For example, the fiber  220  may comprise a polyolefin and the fiber  210 may comprise a material with a melting point higher than the melting point of the polyolefin of the shell material  120 . In other instances, the fiber  210  may comprise a polyester, a polyamide or a co-polyamide and the fiber  220  may comprise a material with a lower melting point than a melting point of the polyester, a polyamide or a co-polyamide in the fiber  210 . In additional examples, the fiber  220  may comprise a polyolefin and the fiber  210  may comprise a polyester, a polyamide or a co-polyamide. In some examples, the fiber  220  comprises a polyolefin and the fiber  210  comprises a polyester. In other examples, the fiber  220  comprises a polyolefin and the fiber  210  comprises a polyamide. In some examples, the fiber  220  comprises a polyolefin and the fiber  210  comprises a co-polyamide. 
     In some examples, the polyolefin of the fiber  220  may be polyethylene, polypropylene or other olefinic polymers and co-polymers. In some embodiments, the polyolefin material of the fiber  220  may be considered a linear low density polyolefin. For example, the polyolefin material of the fiber  220  may be a linear low density polyethylene (LLDPE) or a low density polyethylene (LDPE). While the exact material properties can vary, a linear low density polyethylene may comprise a density of about 0.91 g/cm3 to about 0.94 g/cm3. In some examples, a melting point of the LLDPE or LDPE can be at least fifteen degrees Celsius lower than a melting point of the fiber  210 . In certain examples, a melting point of the LLDPE or LDPE can be at least twenty degrees Celsius lower than a melting point of the fiber  210 . In other examples, a melting point of the LLDPE or LDPE can be at least twenty-five degrees Celsius lower than a melting point of the fiber  210 . In certain examples, a melting point of the LLDPE or LDPE can be at least thirty degrees Celsius lower than a melting point of the core material  110 . In other examples, a melting point of the LLDPE or LDPE can be at least thirty-five degrees Celsius lower than a melting point of the fiber  210 . In certain examples, a melting point of the LLDPE or LDPE can be at least forty degrees Celsius lower than a melting point of the fiber  210 . In other examples, a melting point of the LLDPE or LDPE can be at least forty-five degrees Celsius lower than a melting point of the fiber  210 . In some examples, a melting point of the LLDPE or LDPE can be at least fifty degrees Celsius lower than a melting point of the fiber  210 . 
     In other examples, the fiber  210  may comprise a polyester comprising monomeric units of a terephthalate. For example, the polyester may be polyethylene terephthalate, polybutylene terephthalate or polynaphthalene terephthalate. In certain examples, a melting point of the polyester comprising monomeric units of a terephthalate in the fiber  210  may be at least fifteen degrees higher than a melting point of material in the fiber  220 . In some examples, a melting point of the polyester comprising monomeric units of a terephthalate in the fiber  210  may be at least twenty degrees higher than a melting point of material in the fiber  220 . In certain examples, a melting point of the polyester comprising monomeric units of a terephthalate in the fiber  210  may be at least twenty-five degrees higher than a melting point of material in the fiber  220 . In other examples, a melting point of the polyester comprising monomeric units of a terephthalate in the fiber  210  may be at least thirty degrees higher than a melting point of material in the fiber  220 . In certain examples, a melting point of the polyester comprising monomeric units of a terephthalate in the fiber  210  may be at least thirty-five degrees higher than a melting point of material in the fiber  220 . In some examples, a melting point of the polyester comprising monomeric units of a terephthalate in the fiber  210  may be at least forty degrees higher than a melting point of material in the fiber  220 . In other examples, a melting point of the polyester comprising monomeric units of a terephthalate in the fiber  210  may be at least forty-five degrees higher than a melting point of material in the fiber  220 . In additional examples, a melting point of the polyester comprising monomeric units of a terephthalate in the fiber  210  may be at least fifty degrees higher than a melting point of material in the fiber  220 . 
     In some embodiments, the fiber  210  may comprise a polyamide or a co-polyamide. For example, the fiber  210  may comprise nylon, nylon  66 , aramid, polyesteramides, polyetheramides, polyetheresteramides, or other polyamide-containing copolymers. In certain examples, a melting point of the polyamide or co-polyamide in the fiber  210  may be at least fifteen degrees higher than a melting point of material in the fiber  220 . In some examples, a melting point of the polyamide or co-polyamide in the fiber  210  may be at least twenty degrees higher than a melting point of material in the fiber  220 . In certain examples, a melting point of the polyamide or co-polyamide in the fiber  210  may be at least twenty-five degrees higher than a melting point of material in the fiber  220 . In other examples, a melting point of the polyamide or co-polyamide in the fiber  210  may be at least thirty degrees higher than a melting point of material in the fiber  220 . In certain examples, a melting point of the polyamide or co-polyamide in the fiber  210  may be at least thirty-five degrees higher than a melting point of material in the fiber  220 . In some examples, a melting point of the polyamide or co-polyamide in the fiber  210  may be at least forty degrees higher than a melting point of material in the fiber  220 . In other examples, a melting point of the polyamide or co-polyamide in the fiber  210  may be at least forty-five degrees higher than a melting point of material in the fiber  220 . In additional examples, a melting point of the polyamide or co-polyamide in the fiber  210  may be at least fifty degrees higher than a melting point of material in the fiber  220 . 
     In certain examples, the fiber  220  may comprise a polyethylene, e.g., a LLDPE, and the fiber  210  may comprise a polyester or a polyamide. For example, the fiber  210  may comprise nylon, polyethylene terephthalate, polybutylene terephthalate, polynaphthalene terephthalate, or combinations thereof. In certain examples, a melting point of the polyester or polyamide in the fiber  210  may be at least fifteen degrees higher than a melting point of the polyethylene material in the fiber  220 . In some examples, a melting point of the polyester or polyamide in the core fiber  210  may be at least twenty degrees higher than a melting point of the polyethylene material in the fiber  220 . In certain examples, a melting point of the polyester or polyamide in the fiber  210  may be at least twenty-five degrees higher than a melting point of the polyethylene material in the fiber  220 . In other examples, a melting point of the polyester or polyamide in the fiber  210  may be at least thirty degrees higher than a melting point of the polyethylene material in the fiber  220 . In certain examples, a melting point of the polyester or polyamide in the fiber  210  may be at least thirty-five degrees higher than a melting point of the polyethylene material in the fiber  220 . In some examples, a melting point of the polyester or polyamide in the fiber  210  may be at least forty degrees higher than a melting point of the polyethylene material in the fiber 220 . In other examples, a melting point of the polyester or polyamide in the fiber  210  may be at least forty-five degrees higher than a melting point of the polyethylene material in the fiber  220 . In additional examples, a melting point of the polyester or polyamide in the fiber  210  may be at least fifty degrees higher than a melting point of the polyethylene material in the fiber  220 . 
     Referring to  FIG. 3A , an illustration showing a cross-section through a side-by-side fiber arrangement with a shell surrounding the side-by-side fiber arrangement of bi-components fibers is shown. For example, the fiber  300  comprises a shell  320  that surrounds two fibers  310 ,  315 . In  FIG. 3A , the fibers  310 ,  315  may comprise the same or similar compositions. For example, each of the fibers  310 ,  315  may independently comprise the same materials as described in connection with the core material  110  in  FIG. 1 , e.g., each of the fibers  310 ,  315  may independently comprise a polyamide, polyester or other polymer. 
     In certain embodiments, the shell material  320  may comprise a polyolefin. In some examples, the polyolefin of the shell material  320  may be polyethylene, polypropylene or other olefinic polymers and co-polymers. In some embodiments, the polyolefin material of the shell  320  may be considered a linear low density polyolefin. For example, the polyolefin material of the shell  320  may be a linear low density polyethylene (LLDPE) or a low density polyethylene (LDPE). While the exact material properties can vary, a linear low density polyethylene may comprise a density of about 0.91 g/cm3 to about 0.94 g/cm3. In some examples, a melting point of the LLDPE or LDPE can be at least fifteen degrees Celsius lower than a melting point of the fibers  310 ,  315 . In certain examples, a melting point of the LLDPE or LDPE can be at least twenty degrees Celsius lower than a melting point of the fibers  310 ,  315 . In other examples, of the LLDPE or LDPE can be at least twenty-five degrees Celsius lower than a melting point of the fibers  310 ,  315 . In certain examples, a melting point of the LLDPE or LDPE can be at least thirty degrees Celsius lower than a melting point of the fibers  310 ,  315 . In other examples, a melting point of the LLDPE or LDPE can be at least thirty-five degrees Celsius lower than a melting point of the fibers  310 ,  315 . In certain examples, a melting point of the LLDPE or LDPE can be at least forty degrees Celsius lower than a melting point of the fibers  310 ,  315 . In other examples, a melting point of the LLDPE or LDPE can be at least forty-five degrees Celsius lower than a melting point of the fibers  310 ,  315 . In some examples, a melting point of the LLDPE or LDPE can be at least fifty degrees Celsius lower than a melting point of the fibers  310 ,  315 . 
     In certain examples, the fibers  310 ,  315  may independently comprise a polyester or a polyamide. In some instances, the fibers  310 ,  315  independently comprise may comprise nylon, polyethylene terephthalate, polybutylene terephthalate, polynaphthalene terephthalate, or combinations thereof. In certain examples, a melting point of the polyester or polyamide in the fibers  310 ,  315  may be at least fifteen degrees higher than a melting point of the polyethylene material in the shell material  320 . In some examples, a melting point of the polyester or polyamide in the fibers  310 ,  315  may be at least twenty degrees higher than a melting point of the polyethylene material in the shell material  320 . In certain examples, a melting point of the polyester or polyamide in the fibers  310 ,  315  may be at least twenty-five degrees higher than a melting point of the polyethylene material in the shell material  320 . In other examples, a melting point of the polyester or polyamide in the fibers  310 ,  315  may be at least thirty degrees higher than a melting point of the polyethylene material in the shell material  320 . In certain examples, a melting point of the polyester or polyamide in the fibers  310 ,  315  may be at least thirty-five degrees higher than a melting point of the polyethylene material in the shell material  320 . In some examples, a melting point of the polyester or polyamide in the fibers  310 ,  315  may be at least forty degrees higher than a melting point of the polyethylene material in the shell material  320 . In other examples, a melting point of the polyester or polyamide in the fibers  310 ,  315  may be at least forty-five degrees higher than a melting point of the polyethylene material in the shell material  320 . In additional examples, a melting point of the polyester or polyamide in the fibers  310 ,  315  may be at least fifty degrees higher than a melting point of the polyethylene material in the shell material  320 . 
     While  FIG. 3A  shows two side-by-side fibers which may comprise the same composition, this configuration is not required. For example and referring to  FIG. 3B , a side-by-side arrangement of fibers  360 ,  365  surrounded by a shell  370  is shown. The fibers  360 ,  365  need not have the same composition as each other, but the melting point of each of the fibers  360 ,  365  is typically higher than a melting point of the shell  370  in the fiber arrangement  350 . In one configuration, one of the fibers  360 ,  365  is a reinforcing fiber as noted below, e.g., inorganic fibers such as glass fibers, graphite fibers, carbon fibers, etc., and the other of the fibers  360 ,  365  is an organic fiber, e.g., comprises one or more covalently bonded carbon-hydrogen groups. By packaging the inorganic and organic fibers in a shell, addition of the fibers during processing of the materials to form a core layer can be simplified. In other examples, the fibers  360 ,  365  can each be organic fibers with a different composition. 
     In certain embodiments, the shell material  370  may comprise a polyolefin. In some examples, the polyolefin of the shell material  370  may be polyethylene, polypropylene or other olefinic polymers and co-polymers. In some embodiments, the polyolefin material of the shell  370  may be considered a linear low density polyolefin. For example, the polyolefin material of the shell  370  may be a linear low density polyethylene (LLDPE) or a low density polyethylene (LDPE). While the exact material properties can vary, a linear low density polyethylene may comprise a density of about 0.91 g/cm3 to about 0.94 g/cm3. In some examples, a melting point of the LLDPE or LDPE can be at least fifteen degrees Celsius lower than a melting point of the fibers  360 ,  365 . In certain examples, a melting point of the LLDPE or LDPE can be at least twenty degrees Celsius lower than a melting point of the fibers  360 ,  365 . In other examples, of the LLDPE or LDPE can be at least twenty-five degrees Celsius lower than a melting point of the fibers  360 ,  365 . In certain examples, a melting point of the LLDPE or LDPE can be at least thirty degrees Celsius lower than a melting point of the fibers  360 ,  365 . In other examples, a melting point of the LLDPE or LDPE can be at least thirty-five degrees Celsius lower than a melting point of the fibers  360 ,  365 . In certain examples, a melting point of the LLDPE or LDPE can be at least forty degrees Celsius lower than a melting point of the fibers  360 ,  365 . In other examples, a melting point of the LLDPE or LDPE can be at least forty-five degrees Celsius lower than a melting point of the fibers  360 ,  365 . In some examples, a melting point of the LLDPE or LDPE can be at least fifty degrees Celsius lower than a melting point of the fibers  360 ,  365 . 
     In certain examples, the fibers  360 ,  365  may independently comprise a polyester or a polyamide or one of the fibers  360 ,  365  may be an inorganic reinforcing fiber. In some instances, the fibers  360 ,  365  independently comprise may comprise nylon, polyethylene terephthalate, polybutylene terephthalate, polynaphthalene terephthalate, or combinations thereof. In certain examples, a melting point of the materials in the fibers  360 ,  365 may be at least fifteen degrees higher than a melting point of the polyethylene material in the shell material  370 . In some examples, a melting point of the materials in the fibers  360 ,  365 may be at least twenty degrees higher than a melting point of the polyethylene material in the shell material  370 . In certain examples, a melting point of the materials in the fibers  360 ,  365  may be at least twenty-five degrees higher than a melting point of the polyethylene material in the shell material  370 . In other examples, a melting point of the materials in the fibers  360 ,  365  may be at least thirty degrees higher than a melting point of the polyethylene material in the shell material  370 . In certain examples, a melting point of the materials in the fibers  360 ,  365  may be at least thirty-five degrees higher than a melting point of the polyethylene material in the shell material  320 . In some examples, a melting point of the materials in the fibers  360 ,  365  may be at least forty degrees higher than a melting point of the polyethylene material in the shell material  370 . In other examples, a melting point of the materials in the fibers  360 ,  365  may be at least forty-five degrees higher than a melting point of the polyethylene material in the shell material  370 . In additional examples, a melting point of the materials in the fibers  360 ,  365  may be at least fifty degrees higher than a melting point of the polyethylene material in the shell material  370 . 
     In certain embodiments and referring to  FIG. 4 , a core layer  410  is shown that comprises a thermoplastic material, reinforcing fibers, bicomponent fibers and a lofting agent. As discussed further below, the combination of these materials can provide improved mechanical properties. While not true in all configurations, the lofting agent typically becomes trapped in the voids or pores of the core layer  410 . The core layer  410  may first be formed as a prepreg which is generally a precursor to the core layer  410  and is not necessarily fully formed. For ease of illustration, a core layer is described below, though the properties of the core layer may also be the same as a prepreg. The core layer  410  comprises a porous structure to permit gases to flow through the core layer. For example, the core layer may comprise a void content or porosity of 0-30%, 10-40%, 20-50%, 30-60%, 40-70%, 50-80%, 60-90%, 0-40%, 0-50%, 0-60%, 0-70%, 0-80%, 0-90%, 10-50%, 10-60%, 10-70%, 10-80%, 10-90%, 10-95%, 20-60%, 20-70%, 20-80%, 20-90%, 20-95%, 30-70%, 30-80%, 30-90%, 30-95%, 40-80%, 40-90%, 40-95%, 50-90%, 50-95%, 60-95% 70-80%, 70-90%, 70-95%, 80-90%, 80-95% or any illustrative value within these exemplary ranges. In some instances, the core layer  410  comprises a porosity or void content of greater than 0%, e.g., is not fully consolidated, up to about 95%. Unless otherwise stated, the reference to the core layer comprising a certain void content or porosity is based on the total volume of the core layer and not necessarily the total volume of the core layer plus any other materials or layers coupled to the core layer. 
     In certain embodiments, by including the polymeric bicomponent fibers in the core layer  410  improved mechanical properties can be achieved. For example, increasing the amount of the reinforcing fibers in the core layer  410  can often degrade certain mechanical properties. Inclusion of the bicomponent fibers in the core layer can, for example, improve one or more of peak load values, stiffness values, flexural strength values and flexural modulus values for a selected molding thickness. These values can be measured, for example, using SAEJ949 dated April 2009 (also referred to as SAEJ949_200904). In brief, the SAEJ949 protocol used subjects a sample to a three-point bending test and measures the various performance values. 
     In certain embodiments, the thermoplastic material of the core layer  410  may comprise, at least in part, one or more of polyethylene, polypropylene, polystyrene, acrylonitrylstyrene, butadiene, polyethyleneterephthalate, polybutyleneterephthalate, polybutylenetetrachlorate, and polyvinyl chloride, both plasticized and unplasticized, and blends of these materials with each other or other polymeric materials. Other suitable thermoplastics include, but are not limited to, polyarylene ethers, polycarbonates, polyestercarbonates, thermoplastic polyesters, polyimides, polyetherimides, polyamides, acrylonitrile-butylacrylate-styrene polymers, amorphous nylon, polyarylene ether ketone, polyphenylene sulfide, polyaryl sulfone, polyether sulfone, liquid crystalline polymers, poly(1,4 phenylene) compounds commercially known as PARMAX®, high heat polycarbonate such as Bayer&#39;s APEC® PC, high temperature nylon, and silicones, as well as alloys and blends of these materials with each other or other polymeric materials. The virgin thermoplastic material used to form the core layer can be used in powder form, resin form, rosin form, fiber form or other suitable forms. Illustrative thermoplastic materials in various forms are described herein and are also described, for example in U.S. Publication Nos. 20130244528 and US20120065283. The exact amount of thermoplastic material present in the core layer  410  can vary and illustrative amounts range from about 20% by weight to about 80% by weight. As noted herein, the material of the core layer  410  can be selected such that its melting point is about the same as one of the materials in the bicomponent fibers and is less than a melting point of another material in the bicomponent fibers. Illustrative melting point ranges for the thermoplastic material include, but are not limited to, about 120 degrees Celsius to about 260 degrees Celsius. If desired, thermoplastic materials that melt between 100 degrees Celsius and 315 degrees Celsius can also be used. 
     In certain examples, the reinforcing fibers of the core layer described herein can comprise glass fibers, carbon fibers, graphite fibers, synthetic organic fibers, particularly high modulus organic fibers such as, for example, para- and meta-aramid fibers, nylon fibers, polyester fibers, or any high melt flow index resins that are suitable for use as fibers, natural fibers such as hemp, sisal, jute, flax, coir, kenaf and cellulosic fibers, mineral fibers such as basalt, mineral wool (e.g., rock or slag wool), wollastonite, alumina silica, and the like, or mixtures thereof, metal fibers, metalized natural and/or synthetic fibers, ceramic fibers, yarn fibers, or mixtures thereof. In some instances, one type of the reinforcing fibers may be used along with mineral fibers such as, for example, fibers formed by spinning or drawing molten minerals. Illustrative mineral fibers include, but are not limited to, mineral wool fibers, glass wool fibers, stone wool fibers, and ceramic wool fibers. In some examples, the reinforcing fibers can be selected to be inorganic fibers, e.g., fibers not including covalently bonded carbon-hydrogen groups. 
     In some embodiments, any of the aforementioned reinforcing fibers can be chemically treated prior to use to provide desired functional groups or to impart other physical properties to the fibers. The total fiber content in the core layer (reinforcing fibers+bicomponent fibers) may be from about 20% to about 90% by weight of the core layer, more particularly from about 30% to about 70%, by weight of the core layer. Typically, the total fiber content of a composite article comprising the core layer varies between about 20% to about 90% by weight, more particularly about 30% by weight to about 80% by weight, e.g., about 40% to about 70% by weight of the composite. The particular size and/or orientation of the reinforcing fibers used may depend, at least in part, on the polymer material used and/or the desired properties of the resulting core layer. Suitable additional types of fibers, fiber sizes and amounts will be readily selected by the person of ordinary skill in the art, given the benefit of this disclosure. In one non-limiting illustration, reinforcing fibers dispersed within a thermoplastic material to provide a core layer generally have a diameter of greater than about 5 microns, more particularly from about 5 microns to about 22 microns, and a length of from about 5 mm to about 200 mm. More particularly, the reinforcing fiber diameter may be from about 5 microns to about 22 microns and the fiber length may be from about 5 mm to about 75 mm. In some configurations, the flame retardant material may be present in fiber form. For example, the core layer may comprise a thermoplastic material, reinforcing fibers, bicomponent fibers and fibers comprising a flame retardant material. 
     In some configurations, the core layer  410  may be a substantially halogen free or halogen free layer to meet the restrictions on hazardous substances requirements for certain applications. In other instances, the core layer  410  may comprise a halogenated flame retardant agent (which can be present in the flame retardant material or may be added in addition to the flame retardant material) such as, for example, a halogenated flame retardant that comprises one of more of F, Cl, Br, I, and At or compounds that including such halogens, e.g., tetrabromo bisphenol-A polycarbonate or monohalo-, dihalo-, trihalo- or tetrahalo-polycarbonates. In some instances, the thermoplastic material used in the core layer  410  may comprise one or more halogens to impart some flame retardancy without the addition of another flame retardant agent. For example, the thermoplastic material may be halogenated in addition to there being a flame retardant material present, or the virgin thermoplastic material may be halogenated and used by itself. Where halogenated flame retardants are present, the flame retardant is desirably present in a flame retardant amount, which can vary depending on the other components which are present. For example, the halogenated flame retardant where present in addition to the flame retardant material may be present in about 0.1 weight percent to about 40 weight percent (based on the weight of the prepreg), more particularly about 0.1 weight percent to about 15 weight percent, e.g., about 5 weight percent to about 15 weight percent. If desired, two different halogenated flame retardants may be added to the core layer  410 . In other instances, a non-halogenated flame retardant agent such as, for example, a flame retardant agent comprising one or more of N, P, As, Sb, Bi, S, Se, and Te can be added. In some embodiments, the non-halogenated flame retardant may comprise a phosphorated material so the core layer  410  may be more environmentally friendly. Where non-halogenated or substantially halogen free flame retardants are present, the flame retardant is desirably present in a flame retardant amount, which can vary depending on the other components which are present. For example, the substantially halogen free flame retardant may be present in about 0.1 weight percent to about 40 weight percent (based on the weight of the prepreg), more particularly about 5 weight percent to about 40 weight percent, e.g., about 5 weight percent to about 15 weight percent based on the weight of the core layer. If desired, two different substantially halogen free flame retardants may be added to the core layer  410 . In certain instances, the core layer  410  described herein may comprise one or more halogenated flame retardants in combination with one or more substantially halogen free flame retardants. Where two different flame retardants are present, the combination of the two flame retardants may be present in a flame retardant amount, which can vary depending on the other components which are present. For example, the total weight of flame retardants present may be about 0.1 weight percent to about 40 weight percent (based on the weight of the prepreg or core), more particularly about 5 weight percent to about 40 weight percent, e.g., about 2 weight percent to about 14 weight percent based on the weight of the core layer. The flame retardant agents used in the core layers described herein can be added to the mixture comprising the thermoplastic material, bicomponent fibers and reinforcing fibers (prior to disposal of the mixture on a wire screen or other processing component) or can be added after the core layer  410  is formed. 
     As noted herein, the core layer  410  may comprise a lofting agent present in the pores or voids of the core layer. The lofting agent may take the form of expandable microspheres whose volume can increase upon exposure to heat or other stimulus. For example, a thickness of the core layer  410  can be increased by expanding the lofting agent. The exact amount of the lofting agent present in the core layer  410  may vary, and illustrative amounts include, but are not limited to, about 0.5 weight percent to about 30 weight percent. 
     In certain embodiments, the exact amount of the bicomponent fibers in the core layers described herein may vary. In general, the weight percentages of the bicomponent fibers in the core layer may vary from about 2 weight percent to about 30 weight percent. In some examples, about the same amount of bicomponent fibers and reinforcing fibers are present in the core layer. In some examples, the overall basis weight of the core layer  410  may vary from about 500 gsm to about 3500 gsm. In some examples, lighter core layers with suitable mechanical properties can be more desirable to reduce overall weight, e.g., a basis weight of the core layer  410  can vary from about 750 gsm to about 1500 gsm or about 750 gsm to about 1250 gsm. 
     In certain embodiments, the core layers and/or articles described herein can be generally prepared using the reinforcing fibers, bicomponent fibers, lofting agent and a thermoplastic material as shown in  FIG. 5 . To produce the core layer, a thermoplastic material, reinforcing fibers, bicomponent fibers, lofting agent and optionally other materials can be added or metered into a dispersing foam contained in an open top mixing tank fitted with an impeller at a step  510  to provide an aqueous dispersion of the materials. Without wishing to be bound by any particular theory, the presence of trapped pockets of air of the foam can assist in dispersing the reinforcing fibers, the bicomponent fibers, the thermoplastic material, the lofting agent and any other materials. In some examples, the dispersed mixture of fibers, lofting agent and thermoplastic can be pumped to a head-box located above a wire section of a paper machine via a distribution manifold. For example, the aqueous mixture can be deposited on a moving wire screen or other support element at a step  520 . The foam, not the fibers, lofting agent or thermoplastic material, can then be removed as the dispersed mixture is provided to a moving support such as a wire screen using a pressure, continuously producing a uniform, fibrous wet web with lofting agent trapped in the web. The wet web can be passed through a dryer at a suitable temperature to reduce moisture content and to melt or soften the thermoplastic material and at least one material of the bicomponent fibers to provide a core layer at step  530 . When the hot web exits the dryer, an optional surface or skin layer such as, for example, a textured film may be laminated onto the web by passing the web of reinforcing fiber, bicomponent fibers, thermoplastic material, lofting agent and textured film through the nip of a set of heated rollers. If desired, additional layers such as, for example, another film layer, scrim layer, etc. may also be attached along with the textured film to one side or to both sides of the web to facilitate ease of handling the produced composite. The composite can then be passed through tension rolls and continuously cut (guillotined) into the desired size for later forming into an end composite article. Further information concerning the preparation of such composites, including suitable materials and processing conditions used in forming such composites, are described, for example, in U.S. Pat. Nos. 6,923,494, 4,978,489, 4,944,843, 4,964,935, 4,734,321, 5,053,449, 4,925,615, 5,609,966 and U.S. Patent Application Publication Nos. US 2005/0082881, US2005/0228108, US 2005/0217932, US 2005/0215698, US 2005/0164023, and US 2005/0161865. 
     In another configuration, the core layers and/or articles described herein can be generally prepared using the reinforcing fibers, bicomponent fibers, and a thermoplastic material as shown in  FIG. 6 . To produce the core layer, a thermoplastic material, reinforcing fibers, bicomponent fibers, and optionally other materials can be added or metered into a dispersing foam contained in an open top mixing tank fitted with an impeller to provide an aqueous dispersion at a step  610 . Without wishing to be bound by any particular theory, the presence of trapped pockets of air of the foam can assist in dispersing the reinforcing fibers, the bicomponent fibers, the thermoplastic material, and any other materials. In some examples, the dispersed mixture of fibers and thermoplastic can be pumped to a head-box located above a wire section of a paper machine via a distribution manifold. For example, the aqueous mixture can be deposited on a moving wire screen or other support element at a step  620  to provide a wet web. The foam, not the fibers or thermoplastic material, can then be removed as the dispersed mixture is provided to a moving support such as a wire screen using a pressure, continuously producing a uniform, fibrous wet web. A lofting agent can be then deposited or sprayed on top of the wet web at a step  625  to provide a wet web that includes the lofting agent. The wet web comprising the deposited lofting agent can be passed through a dryer optionally under vacuum or by applying pressure and heat at a suitable temperature to reduce moisture content and to melt or soften the thermoplastic material and at least one material of the bicomponent fibers to provide a core layer at a step  630 . When the hot web exits the dryer, an optional surface or skin layer such as, for example, a textured film may be laminated onto the web by passing the web of reinforcing fiber, bicomponent fibers, thermoplastic material, lofting agent and textured film through the nip of a set of heated rollers. If desired, additional layers such as, for example, another film layer, scrim layer, etc. may also be attached along with the textured film to one side or to both sides of the web to facilitate ease of handling the produced composite. The composite can then be passed through tension rolls and continuously cut (guillotined) into the desired size for later forming into an end composite article. In certain embodiments, the core layers described herein can be used with a skin layer to provide a composite article. Referring to  FIG. 7 , a skin layer  720  is shown as being disposed on a first surface of the core layer  410  to provide a composite article  700 . The skin layer  720  may comprise, for example, a film, a scrim (e.g., fiber based scrim), a frim (film+scrim), a foil, a woven fabric, a non-woven fabric or be present as an inorganic coating, an organic coating, or a thermoset coating disposed on the core layer. In other instances, the layer  720  may comprise a limiting oxygen index greater than about 22, as measured per ISO 4589 dated 1996. Where a fiber based scrim is present as (or as part of) the skin layer  720 , the fiber based scrim may comprise at least one of glass fibers, aramid fibers, graphite fibers, carbon fibers, inorganic mineral fibers, metal fibers, metalized synthetic fibers, and metalized inorganic fibers. Where a thermoset coating is present as (or as part of) the layer  720 , the coating may comprise at least one of unsaturated polyurethanes, vinyl esters, phenolics and epoxies. Where an inorganic coating is present as (or as part of) the layer  720 , the inorganic coating may comprise minerals containing cations selected from Ca, Mg, Ba, Si, Zn, Ti and Al or may comprise at least one of gypsum, calcium carbonate and mortar. Where a non-woven fabric is present as (or as part of) the layer  720 , the non-woven fabric may comprise a thermoplastic material, a thermal setting binder, inorganic fibers, metal fibers, metallized inorganic fibers and metallized synthetic fibers. If desired, an intermediate layer (not shown) can be present between the core layer and the skin layer  720 . For example, an adhesive layer or layer of other material can be present between the core layer  410  and the skin layer  720 . 
     In some examples, a composite article may also comprise a second skin layer disposed on another surface of a core layer. Referring to  FIG. 8 , a composite article  800  is shown comprising skin layers  720 ,  820  that sandwich a core layer  410 . The layer  820  may be the same or may be different than the layer  720 . In some instances, the layer  820  may comprise, for example, a film, a scrim (e.g., fiber based scrim), a frim (film+scrim), a foil, a woven fabric, a non-woven fabric or be present as an inorganic coating, an organic coating, or a thermoset coating disposed on the core layer. In other instances, the layer  820  may comprise a limiting oxygen index greater than about 22, as measured per ISO 4589 dated 1996. Where a fiber based scrim is present as (or as part of) the layer  820 , the fiber based scrim may comprise at least one of glass fibers, aramid fibers, graphite fibers, carbon fibers, inorganic mineral fibers, metal fibers, metalized synthetic fibers, and metalized inorganic fibers. Where a thermoset coating is present as (or as part of) the layer  820 , the coating may comprise at least one of unsaturated polyurethanes, vinyl esters, phenolics and epoxies. Where an inorganic coating is present as (or as part of) the layer  820 , the inorganic coating may comprise minerals containing cations selected from Ca, Mg, Ba, Si, Zn, Ti and Al or may comprise at least one of gypsum, calcium carbonate and mortar. Where a non-woven fabric is present as (or as part of) the layer  820 , the non-woven fabric may comprise a thermoplastic material, a thermal setting binder, inorganic fibers, metal fibers, metallized inorganic fibers and metallized synthetic fibers. If desired, an intermediate layer (not shown) can be present between the core layer and the skin layer  820 . For example, an adhesive layer or layer of other material can be present between the core layer  410  and the skin layer  820 . 
     In certain configurations, a composite article can include a decorative layer disposed on a surface of the core layer or on a skin layer. Referring to  FIG. 9 , an article  900  is shown that comprises a decorative layer  830  disposed on the skin layer  720 . While not shown, a decorative layer could be disposed on an opposite surface of the core layer  410  or can be disposed on the skin layer  820  shown in  FIG. 8 . In some examples, the decorative layer  930  may be configured as a decorative layer, textured layer, colored layer and the like. For example, a decorative layer  930  may be formed, e.g., from a thermoplastic film of polyvinyl chloride, polyolefins, thermoplastic polyesters, thermoplastic elastomers, or the like. The decorative layer  930  may also be a multi-layered structure that includes a foam core formed from, e.g., polypropylene, polyethylene, polyvinyl chloride, polyurethane, and the like. A fabric may be bonded to the foam core, such as woven fabrics made from natural and synthetic fibers, organic fiber non-woven fabric after needle punching or the like, raised fabric, knitted goods, flocked fabric, or other such materials. The fabric may also be bonded to the foam core with a thermoplastic adhesive, including pressure sensitive adhesives and hot melt adhesives, such as polyamides, modified polyolefins, urethanes and polyolefins. The decorative layer  930  may also be produced using spunbond, thermal bonded, spun lace, melt-blown, wet-laid, and/or dry-laid processes. Insulation or sound absorption layers may also be bonded to one or more surfaces of the articles described herein, and the insulation or sound absorption layers may be open or closed, e.g., an open cell foam or a closed cell foam, as desired. 
     In certain embodiments, the LWRT articles described herein can be molded to a specific thickness. While not necessarily true in all cases, the molding temperature can be selected to increase the overall volume of the lofting agent, which can increase the thickness of the LWRT article. LWRT articles without a lofting agent can also be lofted to some degree during molding if they are compressed during formation of the LWRT article. The exact molding thickness may vary as desired, and typical molding thicknesses vary from about 1 cm to about 10 cm in the machine and cross directions though other molding thickness can also be used. 
     In certain embodiments, as noted herein, the presence of the bicomponent fibers, reinforcing fibers, lofting agent and thermoplastic material in the core layer of the LWRT articles can provide improved mechanical properties for a selected molding thickness. 
     In certain embodiments, an LWRT article comprising a core layer and a skin layer may comprise peak load values of about 10 N/cm to about 40 N/cm in the machine direction and about 5 N/cm to about 30 N/cm in the cross direction as measured by SAEJ949_200904 at a molding thickness from 1.5 cm to 4 cm in the machine and cross directions. 
     In certain embodiments, an LWRT article comprising a core layer and a skin layer may comprise stiffness values of about 6 N/cm to about 50 N/cm in the machine direction and about 3 N/cm to about 30 N/cm in the cross direction as measured by SAEJ949_200904 at a molding thickness from 1.5 cm to 4 cm in the machine and cross directions. 
     In certain embodiments, an LWRT article comprising a core layer and a skin layer may comprise flexural strength values of about 6 N/m 2  to about 20 N/m 2  in the machine direction and about 4 N/m 2  to about 12 N/m 2  in the cross direction as measured by SAEJ949_200904 at a molding thickness from 1.5 cm to 4 cm in the machine and cross directions. 
     In some examples, an LWRT article comprising a core layer and a skin layer may comprise flexural modulus of about 800 N/m 2  to about 1800 N/m 2  in the machine direction and about 500 N/m 2  to about 1600 N/m 2  in the cross direction as measured by SAEJ949_200904 at a molding thickness from 1.5 cm to 4 cm in the machine and cross directions. 
     In certain embodiments, the core layers and articles described herein can be used in building and automotive applications such as, for example, headliners, rear window trims, trunk trims, office partition panels, cabinet back panels, interior automotive panels or other interior automotive articles. 
     In certain embodiments and referring to  FIG. 10 , the articles described herein can be present in a headliner of a vehicle. Illustrative vehicles include, but are not limited to, automotive vehicles, trucks, trains, subways, recreational vehicles, aircraft, ships, submarines, space craft and other vehicles which can transport humans or cargo. In some instances, the headliner typically comprises at least one prepreg or core layer comprising bicomponent fibers, reinforcing fibers, a thermoplastic material, lofting agent, one or more optional skin layers and a decorative layer, e.g., a decorative fabric, disposed on the core layer or on a skin layer. The decorative layer, in addition to being aesthetically and/or visually pleasing, can also enhance sound absorption and may optionally include foam, insulation or other materials. An illustration of a top view of a headliner is shown in  FIG. 10 . The headliner  1000  comprises a body  1010  and an opening  1020 , e.g., for a sunroof, moonroof, etc. The body of the headliner  1010  can be produced using one or more of the core layers described herein, and using a molding machine where the decorative fabric is placed onto a surface of the core layer and pressed with the desired mold to convert the article into a headliner with a desired shape. The opening  1020  may then be provided by trimming the headliner  1000 . The non-visible surface of the headliner, e.g., the surface which rests against the roof of the vehicle, may comprise one or more additional layers or an adhesive as desired. The overall shape and geometry of the headliner may be selected based on the area of the vehicle which the headliner is to be coupled. For example, the length of the headliner can be sized and arranged so it spans from the front windshield to the rear windshield, and the width of the headliner can be sized and arranged so it spans from the left side of the vehicle to the right side of the vehicle. In some examples, the core layer of the headliner  1000  may comprise 20% to 80% by weight reinforcing fibers and bicomponent fibers (collectively) and 20% to 80% by weight thermoplastic material. In other embodiments, the reinforcing fibers comprise glass fibers and the thermoplastic material comprises a polyolefin. The bicomponent fibers may comprise a core-shell arrangement or other arrangements as described herein. In some examples, the automotive headliner may provide peak load values, stiffness values, flexural strength values and/or flexural modulus values as discussed herein in connection with the core layer. 
     In certain instances, core layers can also be used to produce other automotive interior components including panels, trim pieces and the like. An illustration of a rear window trim  1100  (top view) is shown in  FIG. 11 . The trim  1100  may comprise one or more of the core layers as described herein optionally with a skin layer and/or a decorative layer. In some examples, the core layer of the automotive components such as trim pieces may comprise 20% to 80% by weight reinforcing fibers and bicomponent fibers (collectively) and 20% to 80% by weight thermoplastic material. In other embodiments, the reinforcing fibers comprise glass fibers and the thermoplastic material comprises a polyolefin. The bicomponent fibers may comprise a core-shell arrangement or other arrangements as described herein. In some examples, the automotive trim or interior components may provide peak load values, stiffness values, flexural strength values and/or flexural modulus values as discussed herein in connection with the core layer. 
     In other configurations, the bicomponent fibers described herein can be used in non-automotive articles such as furniture. For example and referring to  FIG. 12 , a display cabinet  1200  is shown that comprises a top surface  1110 , side surfaces  1212 ,  1214  coupled to the front surface  1210  and a back surface  1220  coupled to the side surfaces  1212 ,  1214 . The surfaces  1210 ,  1212 ,  1214 , and  1220  together form a user accessible interior storage area. While not shown the cabinet  1200  may comprise a front surface, e.g., a glass surface or other materials to view the contents of the cabinet. Alternatively, a door or other device can be attached to the cabinet  1200  to shield the contents within the cabinet  1200  from view. One or more surfaces of the cabinet  1200  may be configured as a LWRT article with a core layer comprising TP material, reinforcing fibers and bicomponent fibers. In some examples, the back surface  1220  may comprise a core layer comprising a web of reinforcing fibers and bicomponent fibers held together by a thermoplastic material. Where more than one of the surfaces of the article  1200  comprises bicomponent fibers in a layer, the layers need not have the same composition, thickness or number of layers. In some examples, the core layer of the furniture article  1200  may comprise 20% to 80% by weight reinforcing fibers and bicomponent fibers (collectively) and 20% to 80% by weight thermoplastic material. In other embodiments, the reinforcing fibers comprise glass fibers and the thermoplastic material comprises a polyolefin. The bicomponent fibers may comprise a core-shell arrangement or other arrangements. In some examples, the furniture article  1200 , or a panel thereof, may provide peak load values, stiffness values, flexural strength values and/or flexural modulus values as discussed herein in connection with the core layer. 
     In some configurations, the furniture article can be configured to receive at least one drawer. For example and referring to  FIG. 13 , a cabinet  1300  is shown as comprising a drawer  1310  and a back surface  1320 . The back surface  1320 , for example, may comprise a LWRT article as described herein, e.g., one with bicomponent fibers. Other surfaces of the cabinet  1300  may also comprise a LWRT article as described herein. In other configurations, the furniture article  1300  can be configured to receive (or may comprise) at least one door. Referring to  FIG. 14 , a cabinet  1400  comprises a door  1410  and a back surface  1420 . The back surface  1420 , for example, may comprise a LWRT article as described herein. Other surfaces of the cabinet  1400  may also comprise a LWRT article described herein. If desired, an outer surface of the door  1410  may comprise a LWRT as described herein. Where the cabinet comprises a door, the door need not be a closable by way of a hinges  1412 ,  1414 . Instead, the door could be configured as a sliding door  1510  as shown in the cabinet  1500  of  FIG. 15 . 
     Certain specific examples are described to illustrate further some of the aspects of the technology described herein. 
     EXAMPLE 1 
     Several samples were prepared and tested to determine the properties of composite articles that included the bicomponent fibers. The materials used in the tested samples and their numbering are shown in Table 1 below. PP refers to polypropylene. The polymeric fibers that were tested were core-shell bicomponent fibers with LLDPE in the shell and polyethylene terephthalate in the core. 
     
       
         
           
               
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Core 
                   
                   
                   
                   
                   
                   
               
               
                   
                 basis 
                   
                   
                 Poly- 
                 Micro- 
               
               
                   
                 weight 
                   
                 Glass 
                 meric 
                 sphere 
               
               
                 ST # 
                 gsm 
                 PP % 
                 % 
                 fiber % 
                 % 
                 Film 
                 Scrim 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 ST- 
                 900 
                 45 
                 40 
                 15 
                 0 
                 70 gsm 
                 20 gsm 
               
               
                 12242 
                   
                   
                   
                   
                   
                 adhesive 
                 scrim 
               
               
                   
                   
                   
                   
                   
                   
                 film 
               
               
                 ST- 
                 700 
                 45 
                 40 
                 15 
                 0 
                 70 gsm 
                 20 gsm 
               
               
                 12243 
                   
                   
                   
                   
                   
                 adhesive 
                 scrim 
               
               
                   
                   
                   
                   
                   
                   
                 film 
               
               
                 ST- 
                 900 
                 44.1 
                 39.2 
                 14.7 
                 2 
                 70 gsm 
                 20 gsm 
               
               
                 12244 
                   
                   
                   
                   
                   
                 adhesive 
                 scrim 
               
               
                   
                   
                   
                   
                   
                   
                 film 
               
               
                 ST- 
                 700 
                 44.1 
                 39.2 
                 14.7 
                 2 
                 70 gsm 
                 20 gsm 
               
               
                 12245 
                   
                   
                   
                   
                   
                 adhesive 
                 scrim 
               
               
                   
                   
                   
                   
                   
                   
                 film 
               
               
                   
               
            
           
         
       
     
     EXAMPLE 2 
     The composite articles of Example 1 were molded to different thicknesses. Table 2 below lists some of the different thickness for the different articles. MD refers to the longitude direction of the tested specimen matches the machine direction, and CD refers to that the longitude direction of the tested specimen matches the cross-machine direction. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
             
            
               
                   
                   
               
               
                   
                 Molding Thickness (cm) 
                   
               
            
           
           
               
               
               
               
            
               
                   
                 ST Number 
                 MD 
                 CD 
               
               
                   
                   
               
               
                   
                 ST-12242a 
                 2.1 
                 2.1 
               
               
                   
                 ST-12242b 
                 2.6 
                 2.6 
               
               
                   
                 ST-12242c 
                 3.0 
                 3.1 
               
               
                   
                 ST-12242d 
                 3.3 
                 3.4 
               
               
                   
                 ST-12243a 
                 1.6 
                 1.4 
               
               
                   
                 ST-12243b 
                 1.8 
                 1.9 
               
               
                   
                 ST-12243c 
                 2.5 
                 2.5 
               
               
                   
                 ST-12244a 
                 2.5 
                 2.5 
               
               
                   
                 ST-12244b 
                 3.0 
                 3.1 
               
               
                   
                 ST-12244c 
                 3.5 
                 3.6 
               
               
                   
                 ST-12244d 
                 4.0 
                 4.0 
               
               
                   
                 ST-12245a 
                 2.0 
                 2.0 
               
               
                   
                 ST-12245b 
                 2.6 
                 2.5 
               
               
                   
                 ST-12245c 
                 3.2 
                 3.1 
               
               
                   
                   
               
            
           
         
       
     
     EXAMPLE 3 
     Peak load values of the test samples were measured using SAEJ949_200904. A three point bending test was used with the film side of the test samples facing the load in the three point bending test. The measured peak load values for the tested samples is shown in Table 3 below. 
                                             TABLE 3                               Peak Load                           (Newtons)           ST Number   MD   STD. DEV.   CD   STD. DEV.                                                                ST-12242a   22.5   1.7   14.4   0.8           ST-12242b   25.2   2.0   17.0   0.8           ST-12242c   28.5   2.8   17.3   1.2           ST-12242d   33.2   3.6   21.3   1.0           ST-12243a   11.9   1.1   6.2   0.6           ST-12243b   13.5   0.9   8.7   1.5           ST-12243c   17.6   1.7   13.2   1.2           ST-12244a   32.2   1.2   21.1   1.6           ST-12244b   30.5   2.2   20.0   1.5           ST-12244c   35.3   2.1   22.4   1.0           ST-12244d   36.5   1.7   26.6   2.4           ST-12245a   18.5   1.8   12.8   0.6           ST-12245b   20.1   2.2   14.2   1.2           ST-12245c   20.0   2.0   14.3   2.6                        
For all the tested samples, as molding thickness increases, the peak load values in the machine and cross directions generally increase. In comparing the peak load values of samples with microspheres (ST-12244 and ST-12245) to those samples without microspheres (ST-12242 and ST-12243), peak load is generally higher for microsphere based samples at a similar thickness. For example, at 2.6 cm thickness, the 990 gsm ST-12242b sample had peak load values of 25.2 and 17.0 in the machine direction and cross-directions respectively. At 2.5 cm thickness, the 990 gsm ST-12244a sample had peak load values of 32.2 and 21.1 in the machine direction and cross-directions, respectively. A similar result is observed for the 790 gsm samples where, for example, the MD and CD peak load values of ST-12245a are larger than the MD and CD peak load values for ST-12243c. These results are consistent with the combination of thermoplastic material, reinforcing fibers, polymeric fibers and microspheres providing improved peak loads at a selected basis weight and molding thickness.
 
     EXAMPLE 4 
     Stiffness values of the test samples were measured using SAEJ949_200904. A three point bending test was used with the film side of the test samples facing the load in the three point bending test. The measured stiffness values for the tested samples is shown in Table 4 below. 
                                     TABLE 4                       Stiffness (N/cm)               ST Number   MD   STD. DEV.   CD   STD. DEV.                                                    ST-12242a   13.3   1.1   10.0   0.4       ST-12242b   21.0   1.1   17.3   1.8       ST-12242c   27.6   1.7   21.3   1.7       ST-12242d   37.5   1.4   26.2   3.2       ST-12243a   6.4   1.1   3.4   0.3       ST-12243b   8.0   0.9   6.0   1.2       ST-12243c   15.1   1.4   12.7   1.1       ST-12244a   22.2   1.0   14.7   1.2       ST-12244b   27.4   1.8   16.3   2.2       ST-12244c   36.0   3.1   23.3   1.8       ST-12244d   45.7   1.8   29.8   2.4       ST-12245a   10.1   1.1   7.6   0.3       ST-12245b   15.2   1.0   11.5   0.9       ST-12245c   22.2   1.7   14.3   1.9                    
Stiffness was generally lower with the lighter articles that included less fibers. In comparing the stiffness values of samples with microspheres (ST-12244 and ST-12245) to those samples without microspheres (ST-12242 and ST-12243), stiffness is the same or higher for microsphere based samples at a similar thickness. For example, at about 2.6 cm molding thickness, the 990 gsm ST-12242b sample had stiffness value of 21.0 in the machine direction. At 2.5 cm molding thickness, the 990 gsm ST-12244a sample had a stiffness value of 22.2. For these same samples, stiffness in the cross-direction decreased in the presence of the microspheres. For the 790 gsm samples, the MD and CD stiffness values (10.1 and 7.6) of ST-12245a are less than the MD and CD stiffness values (15.1 and 12.7) for ST-12243c. These results are consistent with the bicomponent fibers and microspheres providing the same or a more flexible article than results in the absence of the microspheres.
 
     EXAMPLE 5 
     Flexural strength values of the test samples were measured using SAEJ949_200904. A three point bending test was used with the film side of the test samples facing the load in the three point bending test. The measured flexural strength values for the tested samples is shown in Table 5 below. 
                                     TABLE 5                       Flexural                       Strength (MPa)       ST Number   MD   STD. DEV.   CD   STD. DEV.                                                    ST-12242a   15.9   1.1   9.5   0.6       ST-12242b   11.3   1.0   7.4   0.8       ST-12242c   9.4   1.3   5.5   0.4       ST-12242d   9.3   1.5   5.6   0.5       ST-12243a   14.1   1.5   10.2   1.0       ST-12243b   12.8   1.8   7.6   1.6       ST-12243c   8.9   1.8   6.3   0.3       ST-12244a   15.1   0.8   9.9   0.9       ST-12244b   10.0   1.1   6.5   0.5       ST-12244c   8.9   0.9   5.3   0.4       ST-12244d   6.8   0.4   5.2   0.6       ST-12245a   14.5   0.9   10.2   0.5       ST-12245b   9.2   0.9   6.9   0.5       ST-12245c   6.1   0.4   4.5   0.9                    
Flexural strength generally decreased with increased molding thickness. Flexural strength was also generally lower with the lighter articles that included less fibers. In comparing the flexural strength of samples with microspheres (ST-12244 and ST-12245) to those samples without microspheres (ST-12242 and ST-12243), flexural strength is the same or higher for microsphere based samples at a similar thickness. For example, at about 2.6 cm molding thickness, the 990 gsm ST-12242b sample had a flexural strength of 11.3 in the machine direction. At 2.5 cm molding thickness, the 990 gsm ST-12244a sample had a flexural strength of 15.1. For these same samples, flexural strength in the cross-direction increased slightly in the presence of the microspheres. For the 790 gsm samples, the MD and CD flexural strength values (14.5 and 10.2) of ST-12245a were much higher than the MD and CD flexural strength values (8.9 and 6.3) for ST-12243c. These results are consistent with the bicomponent fibers and microspheres providing the same or better flexural strength.
 
     EXAMPLE 6 
     Flexural modulus values of the test samples were measured using SAEJ949_200904. A three point bending test was used with the film side of the test samples facing the load in the three point bending test. The measured flexural modulus values for the tested samples is shown in Table 6 below. 
                                     TABLE 6                       Flexural                       Modulus (MPa)       ST Number   MD   STD. DEV.   CD   STD. DEV.                                                    ST-12242a   1742.3   91.3   1199.8   56.9       ST-12242b   1389.3   26.8   1108.0   190.6       ST-12242c   1154.7   159.2   839.3   78.3       ST-12242d   1228.7   247.8   789.5   120.4       ST-12243a   1796.8   159.7   1577.7   132.6       ST-12243b   1603.8   192.2   1096.8   278.2       ST-12243c   1195.5   265.8   914.3   40.5       ST-12244a   1582.8   118.7   1048.8   105.3       ST-12244b   1136.7   138.6   660.2   89.5       ST-12244c   1003.8   66.0   587.5   75.1       ST-12244d   819.0   24.3   562.5   60.4       ST-12245a   1546.7   100.5   1204.8   85.0       ST-12245b   1048.8   56.3   867.5   64.7       ST-12245c   816.3   66.6   546.8   80.1                    
Flexural modulus strength generally decreased with increased molding thickness. In comparing the flexural modulus of samples with microspheres (ST-12244 and ST-12245) to those samples without microspheres (ST-12242 and ST-12243), flexural modulus is the same or higher for microsphere based samples at a similar thickness. For example, at about 2.6 cm molding thickness, the 990 gsm ST-12242b sample had a flexural modulus of 1389.6 in the machine direction. At 2.5 cm molding thickness, the 990 gsm ST-12244a sample had a flexural modulus of 1582.8. For these same samples, flexural strength in the cross-direction increased in the presence of the microspheres. For the 790 gsm samples, the MD and CD flexural modulus values (1546.7 and 1204.8) of ST-12245a were much higher than the MD and CD flexural modulus values (1195.5 and 914.3) for ST-12243c. These results are consistent with the bicomponent fibers and microspheres providing the same or better flexural modulus.
 
     EXAMPLE 7 
     The glass/bi-component polymeric fiber hybrid LWRT (H-LWRT) and the standard glass fiber LWRT (S-LWRT) sheets were manufactured by using a same wet-laid process. Polyolefin resin, chopped glass fiber, and bi-component polymeric fiber for H-LWRT were dispersed in water. The aqueous suspension of well dispersed resin and fiber was transferred onto a web-forming section and expanding agents were added to the continuous web. The resulting web was drained, heated, laminated with surface materials (scrim and film) and consolidated to produce flat LWRT composite sheets. Materials with various basis weight (areal densities) can be produced by adjusting the manufacturing parameters. The control sample (S-LWRT) had a basis weight of 650 g/m2, which is about 14.4% heavier than the HLWRT&#39;s basis weight of 568 g/m2. 
     After being heated above the melting point of the resin, the materials experience thickness increase due to the release of residual stress from bent fibers, as well as from the expanding/lofting agent. Therefore, all materials are capable of being molded into thicknesses of 3.5 to 7 mm, which are thicker than the as-produced status/thicknesses (Table 1).  FIG. 16  shows an example part which is molded from a sample B (H-LWRT) sheet. The material shows good formability to adapt to complicated shapes in a mold. 
     Analytical properties including basis weight (areal density), as-produced thickness, and glass (ash) content were measured following standard internal testing procedure. The tensile properties of samples with thickness of 3 mm were measured according to ASTM D790. The flexural properties of the molded specimens with thicknesses of 3.5, 4, 5.5 and 7 mm, were evaluated according to ASTM D638. Table 7 shows the physical properties of the S-LWRT and H-LWRT. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 7 
               
               
                   
               
               
                 Sample 
                 Basis Weight (g/m 2 ) 
                 Thickness (mm) 
                 Ash (%) 
               
               
                   
               
             
            
               
                 Control (S-LWRT) 
                 650 
                 1.02 
                 33.50 
               
               
                 Sample A (H-LWRT) 
                 568 
                 1.12 
                 29.72 
               
               
                 Sample B (H-LWRT) 
                 568 
                 1.20 
                 34.18 
               
               
                   
               
            
           
         
       
     
     The control sample S-LWRT was 82 g/m 2  (14.4%) heavier than the two H-LWRT samples. The S-LWRT shows a slightly lower thickness, indicating a slightly higher consolidation level. Samples A and B (H-LWRT) have different glass contents, due to the different weight percentages of bi-component polymeric fiber. 
     EXAMPLE 8 
     To evaluate the tensile properties of the samples shown in Table 7, molded plaques with a thickness of 3.5 mm were cut into dog-bone tensile specimens by a punch press.  FIG. 17  is a graph showing the tensile modulus, and  FIG. 18  is a graph showing the tensile strength of sample A (H-LWRT), sample B (H-LWRT), and the control (S-LWRT). For both tensile modulus and tensile strength, all three samples show significantly better results in a machine direction (MD) than those in a cross-machine direction (CD). This may be due to the fiber orientation biases favoring the machine direction, which primarily occurs in the headbox. The flow in the head-box is a mix of both shearing and extension. The complicated flow can feature shearing close to the walls and stretch toward the machine direction within the entire domain. As a result, the fibers can be strongly aligned toward the flow direction leading to better mechanical performances in MD. 
     Sample B (H-LWRT) has the best average tensile modulus in MD, while the control (SLWRT) shows only slightly larger average modulus than both sample A and B in CD. For the tensile strength, all three samples show very comparable performances in MD. In CD, sample A shows a similar result to the control, and sample B is only slightly lower than the other two. Notably, the control (S-LWRT) is 82 g/m 2  heavier than both H-LWRT samples. This means that an up to 82 g/m 2  weight reduction without sacrificing the tensile properties is achieved by hybridizing glass fiber with bi-component polymeric fiber. Particularly for tensile properties, the strength is highly dependent on the bonding between resin and fibers. The bi-component polymeric fiber has a component with a melting point lower than the matrix resin. During the heating and consolidation stages, the component with the lower melting point in the polymeric fiber melts and bonds to the glass fiber surface, which is considered to contribute to better resin wet-out around glass fibers. 
     EXAMPLE 9 
     Flexural tests were conducted on specimens molded into 3.5, 4, 5.5 and 7 mm.  FIGS. 19A and 19B  compare the peak load at both MD and CD between sample A (H-LWRT), sample B (HLWRT) and Control (S-LWRT). Just like the tensile properties, peak load results in the MD are also better than those in CD. The peak load is decreased as the thickness increases, owing to the increase of porosity. Through the entire molding thickness range, all three samples show very comparable peak load results. This indicates that an up to 82 g/m2 weight reduction without sacrificing the flexural peak load is achieved by hybridizing glass fiber with bi-component polymeric fiber. 
     When introducing elements of the examples disclosed herein, the articles “a,” “an,” “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including” and “having” are intended to be open-ended and mean that there may be additional elements other than the listed elements. It will be recognized by the person of ordinary skill in the art, given the benefit of this disclosure, that various components of the examples can be interchanged or substituted with various components in other examples. 
     Although certain aspects, examples and embodiments have been described above, it will be recognized by the person of ordinary skill in the art, given the benefit of this disclosure, that additions, substitutions, modifications, and alterations of the disclosed illustrative aspects, examples and embodiments are possible.