Prepregs, cores and composite articles comprising synergistic and blended flame retardant materials

Abstract

Prepregs, core layers, and composite articles comprising one or more flame retardant materials are described. In some cases, a thermoplastic composite article includes a porous core layer comprising a plurality of reinforcing fibers, a first thermoplastic material, and a second thermoplastic material from a blended flame retardant material comprising the second thermoplastic material and a flame retardant material. In other cases, a thermoplastic composite article includes a porous core layer comprising a plurality of reinforcing fibers, a first thermoplastic material, an expandable graphite material, and a Group II metal hydroxide or Group III metal hydroxide.

Description

[0001] This application is a divisional application of application number 201780015323.X filed on January 4, 2017, and the invention name is "Prepregs, cores and composite articles including synergistic and mixed flame retardant materials".

[0002] Priority Application

[0003] This application is related to and claims priority to and the benefit of U.S. Provisional Application No. 62 / 275,044, filed on January 5, 2016, the entire disclosure of which is incorporated herein by reference. Technical Field

[0004] The present application relates to composite articles comprising one or more flame retardants, such as one or more compounded flame retardant materials or a mixture of flame retardant materials. In certain configurations, a composite article comprising a thermoplastic core is described, the thermoplastic core comprising a first thermoplastic material, a plurality of reinforcing fibers, and a second thermoplastic material from the compounded flame retardant material. Background Art

[0005] Articles used in automotive and building material applications are typically designed to meet a number of competing and stringent performance specifications. Summary of the invention

[0006] Certain configurations of the prepregs, cores, and composite articles described herein provide desirable properties including, but not limited to, flame retardancy, the ability to pigment or dye the article to any color, enhanced processability, and enhanced usability.

[0007] In a first aspect, a thermoplastic composite article includes a porous core layer comprising a plurality of reinforcing fibers, a thermoplastic material, and a compounded flame retardant material.

[0008] In certain embodiments, the compounded flame retardant material comprises a hydroxide material compounded with a thermoplastic material. In some cases, the hydroxide material comprises a Group II metal hydroxide, and wherein the compounded flame retardant material is present in an effective amount such that the article meets the Class A standard as tested by ASTM E84 dated 2009. In other embodiments, the thermoplastic material of the compounded flame retardant material comprises the same thermoplastic material as present in the porous core layer. In some configurations, the thermoplastic material of each of the porous core layer and the compounded flame retardant is independently selected from the group consisting of polyethylene, polypropylene, polystyrene, polyimide, polyetherimide, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polybutylene tetrachloroate, polyvinyl chloride, polyphenylene oxide, polycarbonate, polyester carbonate, polyester, acrylonitrile-butyl acrylate-styrene polymer, amorphous nylon, polyarylene ether ketone, polyphenylene sulfide, polyaryl sulfone, polyether sulfone, poly(1,4 phenylene) compound, silicone and mixtures thereof. In some cases, the thermoplastic material of the compounded flame retardant material includes a thermoplastic material different from the thermoplastic material. In some examples, the thermoplastic material of each of the porous core layer and the compounded flame retardant is independently selected from the group consisting of polyethylene, polypropylene, polystyrene, polyimide, polyetherimide, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polybutylene tetrachloroate, polyvinyl chloride, polyphenylene oxide, polycarbonate, polyester carbonate, polyester, acrylonitrile-butyl acrylate-styrene polymer, amorphous nylon, polyarylene ether ketone, polyphenylene sulfide, polyaryl sulfone, polyether sulfone, poly(1,4 phenylene) compound, silicone and mixtures thereof, wherein the thermoplastic material selected for the thermoplastic material of the core layer is different from the thermoplastic material present in the compounded flame retardant material. In other examples, the porous core layer provides flame retardancy and is halogen-free. In other examples, the article comprises a flame retardant in the porous core layer, wherein the flame retardant comprises at least one of: N, P, As, Sb, Bi, S, Se, or Te. In some embodiments, the article comprises a lofting agent in the porous core layer.

[0009] In another aspect, a thermoplastic composite article includes a porous core layer comprising an open-cell structured network comprising randomly crossed reinforcing fibers held together by a first thermoplastic material and a second thermoplastic material from a blended flame retardant material comprising a second thermoplastic material and a flame retardant material.

[0010] In certain embodiments, the compounded flame retardant material comprises a hydroxide material compounded with a second thermoplastic material. In other embodiments, the hydroxide material comprises a Group II metal hydroxide, and wherein the compounded flame retardant material is present in an effective amount such that the article meets the Class A standard as tested by ASTM E84 dated 2009. In certain instances, the second thermoplastic material of the compounded flame retardant material comprises the same thermoplastic material as the first thermoplastic material. In other embodiments, the first thermoplastic material and the second thermoplastic material independently include at least one of the following: polyethylene, polypropylene, polystyrene, polyimide, polyetherimide, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polytetrachlorobutylene, polyvinyl chloride, polyphenylene oxide, polycarbonate, polyester carbonate, polyester, acrylonitrile-butyl acrylate-styrene polymer, amorphous nylon, polyarylene ether ketone, polyphenylene sulfide, polyaryl sulfone, polyether sulfone, poly (1,4 phenylene) compound, silicone and their mixture. In other examples, the first thermoplastic material and the second thermoplastic material include different thermoplastic materials. In some instances, a plurality of reinforcing fibers include at least one of the following: glass fiber, aramid fiber, graphite fiber, carbon fiber, inorganic mineral fiber, metal fiber, metallized synthetic fiber and metallized inorganic fiber. In some instances, the porous core layer provides flame retardancy and is halogen-free. In some embodiments, the article comprises another flame retardant comprising at least one of: N, P, As, Sb, Bi, S, Se, or Te. In other examples, the article comprises a lofting agent in the porous core layer.

[0011] In another aspect, a thermoplastic composite sheet includes a porous core layer comprising a plurality of reinforcing fibers, a first thermoplastic material, and a compounded flame retardant comprising a second thermoplastic material; and a skin layer disposed on at least one surface of the porous core layer.

[0012] In certain embodiments, the sheet includes another porous core layer disposed between the porous core layer and the skin layer. In other embodiments, the other porous core layer includes a plurality of reinforcing fibers, a first thermoplastic material, and a mixed flame retardant including a second thermoplastic material. In some examples, the mixed flame retardant in the porous core layer and the other porous core layer is the same. In other embodiments, the mixed flame retardant in the porous core layer and the other porous core layer is different. In certain examples, the porous core layer provides flame retardancy and is halogen-free. In some configurations, the sheet includes another flame retardant, and the other flame retardant includes at least one of the following: N, P, As, Sb, Bi, S, Se or Te. In other examples, the mixed flame retardant includes a Group II metal hydroxide, and wherein the mixed flame retardant material is present in an effective amount such that the sheet meets the Class A standard as tested by ASTME84. In certain embodiments, the sheet includes a lofting agent in the porous core layer. In other embodiments, the skin layer includes a mixed flame retardant material.

[0013] In another aspect, the thermoplastic composite sheet includes a porous core layer, the porous core layer comprising a mesh of an open-pore structure, the open-pore structure comprising randomly crossed reinforcing fibers fixed together by a first thermoplastic material and a second thermoplastic material from a blended flame retardant material comprising a second thermoplastic material and a flame retardant material; and a surface layer disposed on at least one surface of the porous core layer.

[0014] In some configurations, the sheet includes another porous core layer disposed between the porous core layer and the skin layer. In other configurations, the other porous core layer includes a plurality of reinforcing fibers, a first thermoplastic material, and a mixed flame retardant including a second thermoplastic material. In some embodiments, the mixed flame retardant in the porous core layer and the other porous core layer is the same. In some examples, the mixed flame retardant in the porous core layer and the other porous core layer is different. In other examples, the porous core layer provides flame retardancy and is halogen-free. In some cases, the sheet includes another flame retardant, and the other flame retardant includes at least one of the following: N, P, As, Sb, Bi, S, Se or Te. In other cases, the mixed flame retardant includes a Group II metal hydroxide, and wherein the mixed flame retardant material is present in an effective amount such that the sheet meets the Class A standard as tested by ASTM E84. In some examples, the sheet includes a lofting agent in the porous core layer. In other examples, the skin layer includes a mixed flame retardant material.

[0015] In another aspect, a thermoplastic composite sheet is provided, comprising a porous core layer, the porous core layer comprising a mesh of an open-pore structure, the mesh of the open-pore structure comprising randomly crossed reinforcing fibers fixed together by a first thermoplastic material and a second thermoplastic material from a compounded flame retardant material, the compounded flame retardant material further comprising a Group II metal hydroxide; and a surface layer disposed on at least one surface of the porous core layer, wherein the Group II metal hydroxide is present in the sheet in an effective amount so that the sheet meets Class A standards as tested by ASTM E84.

[0016] In certain embodiments, the sheet includes another porous core layer disposed between the porous core layer and the surface layer. In other embodiments, the other porous core layer includes a plurality of reinforcing fibers, a first thermoplastic material, and a mixed flame retardant including a second thermoplastic material. In some examples, the mixed flame retardant in the porous core layer and the other porous core layer is each the same divalent hydroxide flame retardant material. In some embodiments, the mixed flame retardant in the other porous core layer is different from the divalent hydroxide flame retardant material. In certain examples, the porous core layer provides flame retardancy and is halogen-free. In some examples, the sheet includes another flame retardant in the porous core layer, wherein the other flame retardant includes at least one of the following: N, P, As, Sb, Bi, S, Se or Te. In other examples, the Group II metal hydroxide of the mixed flame retardant includes at least one of calcium hydroxide and magnesium hydroxide. In some cases, the sheet includes a lofting agent in the porous core layer. In other cases, the surface layer includes a mixed flame retardant material.

[0017] In another aspect, a method includes combining a first thermoplastic material, reinforcing fibers, and a compounded flame retardant material comprising a flame retardant material and a second thermoplastic material to form an agitated aqueous foam, placing the agitated aqueous foam onto a linear support, evacuating water to form a web, heating the web to a first temperature equal to or greater than a melting temperature of the first thermoplastic material, and applying pressure to the web to provide a thermoplastic composite sheet.

[0018] In some cases, the combination step includes mixing the first thermoplastic material, the reinforcing fiber, and the compounded flame retardant material until a homogeneous stirred aqueous foam is formed. In some configurations, the method includes heating the web to a second temperature greater than the first temperature, equal to or higher than the melting temperature of the second thermoplastic material of the compounded flame retardant material. In other examples, the method includes heating the web using convection heating. In some cases, the method includes applying pressure to the heated thermoplastic composite sheet. In some examples, the method includes heating the thermoplastic composite sheet using radiation heating. In other embodiments, the method includes placing additional compounded flame retardant materials on the surface of the thermoplastic composite sheet. In some cases, the method includes configuring the compounded flame retardant material to include a divalent metal hydroxide. In certain embodiments, the method includes bonding the thermoplastic composite sheet to the surface layer. In other cases, the method includes configuring the amount of the flame retardant material from the compounded flame retardant material so that the composite sheet is tested as a Class A standard by ASTM E84.

[0019] In another aspect, a method includes combining a first thermoplastic material and reinforcing fibers to form an agitated aqueous foam; placing the agitated aqueous foam onto a linear support; evacuating water to form a web; heating the web to a first temperature equal to or greater than the melting temperature of the first thermoplastic material; adding a compounded flame retardant material to the heated web to provide a composite web, the compounded flame retardant material comprising a flame retardant material and a second thermoplastic material; and applying pressure to the composite web to provide a thermoplastic composite sheet.

[0020] In certain embodiments, the method includes configuring the compounded flame retardant material to include a Group II metal hydroxide. In other embodiments, the method includes configuring the second thermoplastic material to be the same as the first thermoplastic material, so that the second thermoplastic material melts when the compounded flame retardant is added to the heated web. In some instances, the method includes heating the composite web to a second temperature greater than the first temperature, equal to or higher than the melting temperature of the second thermoplastic material of the compounded flame retardant material. In some cases, the method includes heating the web using convection heating. In other instances, the method includes heating the thermoplastic composite sheet using radiation heating. In some cases, the method includes placing additional compounded flame retardant materials on the surface of the thermoplastic composite sheet. In other instances, the method includes adding a lofting agent to the stirred aqueous foam. In some instances, the method includes bonding the thermoplastic composite sheet to the surface layer. In certain configurations, the method includes configuring an amount of the flame retardant material from the compounded flame retardant material such that the composite sheet is Class A as tested by ASTM E84.

[0021] In another aspect, a method includes combining a first thermoplastic material and reinforcing fibers to form an agitated aqueous foam; placing the agitated aqueous foam onto a wire support; evacuating water to form a web; adding a compounded flame retardant material to the web, the compounded flame retardant material comprising a flame retardant material and a second thermoplastic material; heating the web to a first temperature equal to or greater than a melting temperature of the first thermoplastic material and the second thermoplastic material; and applying pressure to the composite web to provide a thermoplastic composite sheet.

[0022] In some cases, the method includes configuring the mixed flame retardant material to include a Group II metal hydroxide. In other examples, the method includes configuring the second thermoplastic material to be the same as the first thermoplastic material. In some embodiments, the method includes configuring the Group II metal hydroxide to include magnesium hydroxide and configuring the second thermoplastic material to include polypropylene. In some examples, the method includes using convection heating to heat the mesh. In other embodiments, the method includes using radiation heating to heat the thermoplastic composite sheet. In some configurations, the method includes placing additional mixed flame retardant materials on the surface of the thermoplastic composite sheet. In some embodiments, the method includes adding a lofting agent to the stirred aqueous foam. In some cases, the method includes bonding the thermoplastic composite sheet to the surface layer. In some examples, the method includes configuring the amount of flame retardant material from the mixed flame retardant material so that the composite sheet is tested as a Class A standard by ASTM E84.

[0023] In another aspect, a prepreg is described, the prepreg comprising a mesh of an open-cell structure formed by fixing a plurality of reinforcing fibers together through a first thermoplastic material and a second thermoplastic material from a mixed flame retardant material. In some cases, the mixed flame retardant material comprises a Group II metal hydroxide. In other cases, each of the first thermoplastic material and the second thermoplastic material is independently selected from the group consisting of polyethylene, polypropylene, polystyrene, polyimide, polyetherimide, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polytetrachlorobutylene, polyvinyl chloride, polyphenylene oxide, polycarbonate, polyester carbonate, polyester, acrylonitrile-butyl acrylate-styrene polymer, amorphous nylon, polyaryletherketone, polyphenylene sulfide, polyarylsulfone, polyethersulfone, poly(1,4 phenylene) compound, silicone and mixtures thereof.

[0024] In another aspect, a thermoplastic article includes a porous core layer comprising a network of open-cell structures formed by a plurality of reinforcing fibers secured together by a first thermoplastic material and a second thermoplastic material from a compounded flame retardant material comprising a flame retardant and a second thermoplastic material, wherein the flame retardant material is present in an effective amount to provide a Class A rating as tested by ASTM E84. In certain configurations, the compounded flame retardant material comprises a Group II metal hydroxide. In other configurations, each of the first thermoplastic material and the second thermoplastic material is independently selected from the group consisting of polyethylene, polypropylene, polystyrene, polyimide, polyetherimide, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polybutylene tetrachloroate, polyvinyl chloride, polyphenylene oxide, polycarbonate, polyester carbonate, polyester, acrylonitrile-butyl acrylate-styrene polymer, amorphous nylon, polyarylene ether ketone, polyphenylene sulfide, polyarylene sulfone, polyether sulfone, poly(1,4 phenylene) compound, silicone and mixtures thereof. In additional configurations, the Group II metal hydroxide is magnesium hydroxide, and the magnesium hydroxide is present in the article at 40% by weight or more.

[0025] In another aspect, a thermoplastic article includes a porous core layer comprising a network of open-cell structures formed by a plurality of reinforcing fibers fixed together by a first thermoplastic material and a second thermoplastic material from a compounded flame retardant material; and a skin layer disposed on at least one surface of the porous core layer, wherein the flame retardant material is present in an effective amount to allow the article to meet the ASTM E84 Class A standard. In some cases, the compounded flame retardant material comprises a Group II metal hydroxide. In other cases, each of the first thermoplastic material and the second thermoplastic material is independently selected from the group consisting of polyethylene, polypropylene, polystyrene, polyimide, polyetherimide, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polybutylene tetrachloroate, polyvinyl chloride, polyphenylene oxide, polycarbonate, polyester carbonate, polyester, acrylonitrile-butyl acrylate-styrene polymer, amorphous nylon, polyarylene ether ketone, polyphenylene sulfide, polyaryl sulfone, polyether sulfone, poly(1,4 phenylene) compound, silicone and mixtures thereof. In some embodiments, the Group II metal hydroxide is magnesium hydroxide, and the magnesium hydroxide is present in the article at 40% by weight or more.

[0026] In another aspect, a method of preparing a thermoplastic composite article by heating a mixture of reinforcing fibers, a thermoplastic material, and a compounded flame retardant material to a first temperature above the melting point of a first and a second thermoplastic material is described, the thermoplastic composite article comprising a plurality of reinforcing fibers, a thermoplastic material, and a compounded flame retardant material comprising a flame retardant material compounded with a second thermoplastic material. In some cases, the method includes selecting the first and second thermoplastic materials to be the same thermoplastic material. In other cases, the method includes selecting the flame retardant material to be a Group II metal hydroxide. In some configurations, the method includes applying pressure to the heated mixture to form the thermoplastic composite article.

[0027] In another aspect, a method for preparing a thermoplastic composite article comprising a plurality of reinforcing fibers and a thermoplastic material is provided by heating a mixture of reinforcing fibers and a thermoplastic material to a first temperature above the melting point of a first thermoplastic material and adding a solid compounded flame retardant material to the molten first thermoplastic material and the heated reinforcing fibers, the compounded flame retardant material comprising a flame retardant material compounded with a second thermoplastic material. In some cases, the method includes heating the thermoplastic material, the reinforcing fibers, and the added compounded flame retardant material to a temperature above the melting temperature of the second thermoplastic material. In other configurations, the method includes applying pressure to the heated mixture to form the thermoplastic composite article.

[0028] In another aspect, a thermoplastic composite article includes a porous core layer comprising a plurality of reinforcing fibers, a thermoplastic material, an expandable graphite material, and a Group II metal hydroxide or a Group III metal hydroxide.

[0029] In some examples, a Group II metal hydroxide or a Group III metal hydroxide is compounded with a thermoplastic material. In other examples, the thermoplastic material of each of the porous core layer and the compounded flame retardant is independently selected from the group consisting of polyethylene, polypropylene, polystyrene, polyimide, polyetherimide, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polytetrachlorobutylene, polyvinyl chloride, polyphenylene oxide, polycarbonate, polyester carbonate, polyester, acrylonitrile-butyl acrylate-styrene polymer, amorphous nylon, polyarylene ether ketone, polyphenylene sulfide, polyaryl sulfone, polyether sulfone, poly (1,4 phenylene) compound, silicone and mixtures thereof. In some embodiments, the thermoplastic material of the compounded flame retardant material comprises a thermoplastic material different from the thermoplastic material. In certain examples, the thermoplastic material of each of the porous core layer and the compounded flame retardant is independently selected from the group consisting of polyethylene, polypropylene, polystyrene, polyimide, polyetherimide, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polybutylene tetrachloroate, polyvinyl chloride, polyphenylene ether, polycarbonate, polyester carbonate, polyester, acrylonitrile-butyl acrylate-styrene polymer, amorphous nylon, polyarylene ether ketone, polyphenylene sulfide, polyarylene sulfone, polyether sulfone, poly(1,4 phenylene) compound, silicone and mixtures thereof, wherein the thermoplastic material selected for the core layer is different from the thermoplastic material present in the compounded flame retardant material. In other examples, the expandable graphite material is present at less than 5% by weight, and the Group II metal hydroxide or the Group III metal hydroxide is present in an effective amount to allow the article to satisfy both the non-oil-immersed and oil-immersed SAE self-extinguishing tests as measured using the SAE J369 method (November 2007 revision). In some examples, the Group II metal hydroxide or the Group III metal hydroxide is present at 9% by weight or more. In certain embodiments, the porous core layer provides flame retardancy and is halogen-free. In some cases, the article includes a flame retardant in the porous core layer, wherein the flame retardant includes at least one of: N, P, As, Sb, Bi, S, Se or Te. In some examples, the article includes a lofting agent in the porous core layer.

[0030] In another aspect, a thermoplastic composite article comprises a porous core layer comprising a network of open cell structures comprising randomly crossed reinforcing fibers held together by a first thermoplastic material, wherein the porous core layer further comprises an expandable graphite material and a Group II metal hydroxide or a Group III metal hydroxide, and wherein the thermoplastic composite article meets the non-oil immersed and oil immersed SAE self-extinguishing tests as measured using SAE J369 method (November 2007 revision).

[0031] In some instances, the article comprises a mixed flame retardant material containing a hydroxide material mixed with a second thermoplastic material. In some embodiments, the second thermoplastic material of the mixed flame retardant material comprises a thermoplastic material identical to the first thermoplastic material. In some cases, the first thermoplastic material and the second thermoplastic material independently comprise at least one of the following: polyethylene, polypropylene, polystyrene, polyimide, polyetherimide, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polytetrachlorobutylene, polyvinyl chloride, polyphenylene oxide, polycarbonate, polyester carbonate, polyester, acrylonitrile-butyl acrylate-styrene polymer, amorphous nylon, polyarylene ether ketone, polyphenylene sulfide, polyaryl sulfone, polyether sulfone, poly (1,4 phenylene) compound, silicone and mixtures thereof. In some instances, the first thermoplastic material and the second thermoplastic material comprise different thermoplastic materials. In some instances, the Group II metal hydroxide comprises magnesium hydroxide. In some examples, a plurality of reinforcing fibers include at least one of glass fiber, aramid fiber, graphite fiber, carbon fiber, inorganic mineral fiber, metal fiber, metallized synthetic fiber and metallized inorganic fiber. In certain embodiments, the porous core layer provides flame retardancy and is halogen-free. In some examples, the article includes another flame retardant, and the other flame retardant includes at least one of N, P, As, Sb, Bi, S, Se or Te. In other examples, the article includes a lofting agent in the porous core layer.

[0032] In another aspect, a thermoplastic composite sheet includes a porous core layer comprising a plurality of reinforcing fibers, a first thermoplastic material, an expandable graphite material, and a Group II metal hydroxide or a Group III metal hydroxide; and a surface layer disposed on at least one surface of the porous core layer.

[0033] In some examples, the sheet includes another porous core layer disposed between the porous core layer and the skin layer. In some examples, the other porous core layer includes a plurality of reinforcing fibers, a second thermoplastic material, an expandable graphite material, and a Group II metal hydroxide or a Group III metal hydroxide. In some cases, the first and second thermoplastic materials are the same. In some embodiments, the first and second thermoplastic materials are different. In other embodiments, the porous core layer provides flame retardancy and is halogen-free. In some examples, the sheet includes another flame retardant, and the other flame retardant includes at least one of the following: N, P, As, Sb, Bi, S, Se or Te. In some examples, the sheet includes a mixed flame retardant containing a Group II metal hydroxide mixed with another thermoplastic material. In other examples, the sheet includes a lofting agent in the porous core layer. In some embodiments, the skin layer includes a mixed flame retardant material.

[0034] In another aspect, a thermoplastic composite sheet includes a porous core layer, the porous core layer comprising a mesh of an open-pore structure, the mesh of the open-pore structure comprising randomly crossed reinforcing fibers fixed together by a first thermoplastic material, wherein the core layer comprises an expandable graphite material and a Group II metal hydroxide or a Group III metal hydroxide in the open-pore structure of the mesh; and a surface layer disposed on at least one surface of the porous core layer.

[0035] In some examples, the sheet includes another porous core layer disposed between the porous core layer and the skin layer. In certain examples, the other porous core layer includes a plurality of reinforcing fibers, a second thermoplastic material, an expandable graphite material, and a Group II metal hydroxide or a Group III metal hydroxide. In some embodiments, the first and second thermoplastic materials are the same. In other embodiments, the first and second thermoplastic materials are different. In some cases, the porous core layer provides flame retardancy and is halogen-free. In other examples, the sheet includes another flame retardant, which includes at least one of the following: N, P, As, Sb, Bi, S, Se or Te. In some examples, the sheet includes a mixed flame retardant containing a Group II metal hydroxide. In other examples, the sheet includes a lofting agent in the porous core layer. In some examples, the skin layer includes a mixed flame retardant material.

[0036] In another aspect, a thermoplastic composite sheet comprises a porous core layer comprising a mesh of an open-pore structure comprising randomly crossed reinforcing fibers fixed together by a first thermoplastic material, wherein the core layer further comprises an expandable graphite material and a Group II metal hydroxide or a Group III metal hydroxide in the open-pore structure of the mesh; and a surface layer disposed on at least one surface of the porous core layer, wherein the core layer comprises 5 wt. % or less of expandable graphite material and an effective amount of a Group II metal hydroxide or a Group III metal hydroxide so that the sheet meets the non-oil immersed and oil immersed SAE self-extinguishing tests as measured using the SAE J369 method (November 2007 revision).

[0037] In some examples, the sheet includes another porous core layer disposed between the porous core layer and the surface layer. In other examples, the other porous core layer includes a plurality of reinforcing fibers, a first thermoplastic material, an expandable graphite material, and a Group II metal hydroxide or a Group III metal hydroxide. In some embodiments, the Group II metal hydroxide or the Group III metal hydroxide of the core layer and the Group II metal hydroxide or the Group III metal hydroxide of the other porous core layer are each the same divalent hydroxide flame retardant material. In some examples, the Group II metal hydroxide or the Group III metal hydroxide of the core layer and the Group II metal hydroxide or the Group III metal hydroxide of the other porous core layer are different hydroxide materials. In some embodiments, the porous core layer provides flame retardancy and is halogen-free. In other embodiments, the sheet includes another flame retardant in the porous core layer, wherein the other flame retardant includes at least one of the following: N, P, As, Sb, Bi, S, Se or Te. In some examples, the Group II metal hydroxide of the flame retardant comprises at least one of calcium hydroxide and magnesium hydroxide. In some cases, the sheet comprises a lofting agent in the porous core layer. In other cases, the surface layer comprises a compounded flame retardant material.

[0038] In another aspect, a method includes combining a first thermoplastic material, reinforcing fibers, an expandable graphite material, and a Group II metal hydroxide or a Group III metal hydroxide to form an agitated aqueous foam, placing the agitated aqueous foam onto a wire support, evacuating water to form a web, heating the web to a first temperature equal to or greater than the melting temperature of the first thermoplastic material, and applying pressure to the web to provide a thermoplastic composite sheet.

[0039] In some instances, the combining step includes mixing a first thermoplastic material, reinforcing fibers, an expandable graphite material, and a Group II metal hydroxide or a Group III metal hydroxide until a homogeneous, stirred aqueous foam is formed. In other instances, the method includes heating the mesh to a second temperature greater than the first temperature to allow the expandable graphite material to be lofted. In some cases, the method includes heating the mesh using convection heating. In other instances, the method includes applying pressure to the heated thermoplastic composite sheet. In some instances, the method includes heating the thermoplastic composite sheet using radiant heating. In some instances, the method includes placing another flame retardant material on the surface of the thermoplastic composite sheet. In some instances, the method includes configuring the another flame retardant material to include a divalent metal hydroxide. In some instances, the method includes bonding the thermoplastic composite sheet to a surface layer. In other examples, the method includes configuring the amounts of expandable graphite material and Group II metal hydroxide or Group III metal hydroxide so that the sheet meets both non-oil immersed and oil immersed SAE self-extinguishing tests as measured using SAE J369 method (November 2007 revision).

[0040] In another aspect, a method includes combining a first thermoplastic material and reinforcing fibers to form an agitated aqueous foam, placing the agitated aqueous foam onto a wire support, evacuating water to form a web, heating the web to a first temperature equal to or greater than the melting temperature of the first thermoplastic material, adding an expandable graphite material and a Group II metal hydroxide or a Group III metal hydroxide to the heated web to provide a composite web, and applying pressure to the composite web to provide a thermoplastic composite sheet.

[0041] In certain instances, the method includes configuring the Group II metal hydroxide to include calcium hydroxide or magnesium hydroxide. In other instances, the method includes configuring the Group II metal hydroxide to include calcium hydroxide or magnesium hydroxide compounded with a polyolefin. In some instances, the method includes heating the composite mesh to a second temperature greater than the first temperature to allow the expandable graphite material to be lofted. In other instances, the method includes using convection heating to heat the mesh. In some cases, the method includes using radiation heating to heat the thermoplastic composite sheet. In other instances, the method includes placing another flame retardant material on the surface of the thermoplastic composite sheet. In some embodiments, the method includes adding a lofting agent to a stirred aqueous foam. In certain instances, the method includes bonding the thermoplastic composite sheet to a surface layer. In some examples, the method includes configuring amounts of expandable graphite material and Group II metal hydroxide or Group III metal hydroxide so that the sheet meets both non-oil immersed and oil immersed SAE self-extinguishing tests as measured using SAE J369 method (November 2007 revision).

[0042] In another aspect, a method includes combining a first thermoplastic material, reinforcing fibers, an expandable graphite material, and a Group II metal hydroxide or a Group III metal hydroxide to form an agitated aqueous foam, placing the agitated aqueous foam onto a wire support, evacuating water to form a web, heating the web to a first temperature equal to or greater than a melting temperature of the first thermoplastic material and less than a lofting temperature of the expandable graphite material, and applying pressure to the web to provide a thermoplastic composite sheet.

[0043] In certain instances, the method includes configuring the Group II metal hydroxide to include calcium hydroxide or magnesium hydroxide. In other instances, the method includes configuring the Group II metal hydroxide to include calcium hydroxide or magnesium hydroxide compounded with a polyolefin. In some instances, the method includes heating the composite mesh to a second temperature greater than the first temperature to allow the expandable graphite material to be lofted. In certain embodiments, the method includes heating the mesh using convection heating. In other embodiments, the method includes heating the thermoplastic composite sheet using radiation heating. In some instances, the method includes placing another flame retardant material on the surface of the thermoplastic composite sheet. In certain configurations, the method includes adding a lofting agent to the stirred aqueous foam. In some embodiments, the method includes bonding the thermoplastic composite sheet to the surface layer. In other cases, the method includes configuring the amounts of expandable graphite material and Group II metal hydroxide or Group III metal hydroxide so that the sheet meets both non-oil immersed and oil immersed SAE self-extinguishing tests as measured using SAE J369 method (November 2007 revision).

[0044] In another aspect, the prepreg comprises a mesh of an open-cell structure formed by fixing a plurality of reinforcing fibers together through a first thermoplastic material, wherein the prepreg further comprises expandable graphite material and a Group II metal hydroxide or a Group III metal hydroxide in the open-cell structure of the mesh. In some cases, the Group II metal hydroxide comprises calcium hydroxide or magnesium hydroxide. In other cases, the first thermoplastic material is selected from the group consisting of polyethylene, polypropylene, polystyrene, polyimide, polyetherimide, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polytetrachlorobutylene, polyvinyl chloride, polyphenylene oxide, polycarbonate, polyester carbonate, polyester, acrylonitrile-butyl acrylate-styrene polymer, amorphous nylon, polyaryletherketone, polyphenylene sulfide, polyarylsulfone, polyethersulfone, poly(1,4 phenylene) compound, silicone and mixtures thereof.

[0045] In another aspect, a thermoplastic article comprises a porous core layer comprising a mesh of open pore structure formed by a plurality of reinforcing fibers secured together by a first thermoplastic material, wherein the core layer further comprises an expandable graphite material and a Group II metal hydroxide or a Group III metal hydroxide in the open pore structure of the mesh, and wherein the amounts of the expandable graphite material and the Group II metal hydroxide or the Group III metal hydroxide are selected so that the article satisfies both non-oil immersed and oil immersed SAE self-extinguishing tests as measured using the SAE J369 method (November 2007 revision). In some configurations, the Group II metal hydroxide comprises calcium hydroxide or magnesium hydroxide. In other cases, the first thermoplastic material is selected from the group consisting of polyethylene, polypropylene, polystyrene, polyimide, polyetherimide, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polybutylene tetrachloroate, polyvinyl chloride, polyphenylene oxide, polycarbonate, polyester carbonate, polyester, acrylonitrile-butyl acrylate-styrene polymer, amorphous nylon, polyarylene ether ketone, polyphenylene sulfide, polyarylene sulfone, polyether sulfone, poly(1,4 phenylene) compound, silicone and mixtures thereof. In some examples, the Group II metal hydroxide is magnesium hydroxide, the magnesium hydroxide is present in the article at 9 wt% or more and the expandable graphite material is present in the article at 5 wt% or less.

[0046] In another aspect, a thermoplastic article includes a porous core layer, the porous core layer comprising a mesh of an open-pore structure formed by a plurality of reinforcing fibers fixed together by a first thermoplastic material, wherein the core layer further comprises an expandable graphite material and a Group II metal hydroxide or a Group III metal hydroxide in the open-pore structure of the mesh; and a surface layer disposed on at least one surface of the porous core layer. In some examples, the Group II metal hydroxide comprises calcium hydroxide or magnesium hydroxide. In other examples, the first thermoplastic material is selected from the group consisting of polyethylene, polypropylene, polystyrene, polyimide, polyetherimide, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polybutylene tetrachloroate, polyvinyl chloride, polyphenylene oxide, polycarbonate, polyester carbonate, polyester, acrylonitrile-butyl acrylate-styrene polymer, amorphous nylon, polyarylene ether ketone, polyphenylene sulfide, polyarylene sulfone, polyether sulfone, poly(1,4 phenylene) compound, silicone and mixtures thereof. In some cases, the Group II metal hydroxide is magnesium hydroxide, the magnesium hydroxide is present in the article at 9 wt% or more and wherein the expandable graphite material is present in the article at 5 wt% or less.

[0047] In another aspect, a method of preparing a thermoplastic composite article by heating a mixture of reinforcing fibers, a thermoplastic material, an expandable graphite material, and a Group II metal hydroxide or a Group III metal hydroxide to a first temperature above the melting point of the thermoplastic material is described, the thermoplastic composite article comprising a plurality of reinforcing fibers, a thermoplastic material, an expandable graphite material, and a Group II metal hydroxide or a Group III metal hydroxide. In some examples, the method includes selecting the Group II metal hydroxide to include calcium hydroxide or magnesium hydroxide. In other examples, the method includes applying pressure to the heated mixture to form the thermoplastic composite article.

[0048] Additional features, aspects, examples, configurations, and implementations are described in greater detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Certain embodiments are described with reference to the accompanying drawings, in which:

[0050] Figure 1 Description of a prepreg comprising a compounded flame retardant material or two or more different flame retardant materials according to certain examples;

[0051] Figure 2A Description of two prepregs comprising different loadings of a compounded flame retardant material or two or more different flame retardant materials according to certain examples;

[0052] Figure 2B To show Figure 2ADescription of two prepregs after being melted together according to certain configurations;

[0053] Figure 2C To illustrate the bonding of a prepreg comprising a compounded flame retardant material (or two or more different flame retardant materials) to a skin layer according to certain embodiments;

[0054] Figure 3 To illustrate the bonding of a prepreg or core comprising a compounded flame retardant material (or two or more different flame retardant materials) to a skin layer according to certain examples;

[0055] Figure 4 To illustrate that a prepreg or core comprising a compounded flame retardant material (or two or more different flame retardant materials) is bonded to two skin layers according to certain examples;

[0056] Figure 5 To illustrate another illustration of a prepreg or core comprising a compounded flame retardant material (or two or more different flame retardant materials) bonded to two skin layers according to certain examples;

[0057] Figure 6 To illustrate another illustration of two prepregs or cores comprising a compounded flame retardant material (or two or more different flame retardant materials) bonded to each other via a skin layer according to certain examples;

[0058] Figure 7 To illustrate that two prepregs or cores comprising a compounded flame retardant material (or two or more different flame retardant materials) are bonded to each other, and a skin layer is disposed on one of the core layers according to certain embodiments;

[0059] Figure 8 To illustrate that two prepregs or cores comprising a compounded flame retardant material (or two or more different flame retardant materials) are bonded to each other, and a skin layer is disposed on each of the core layers according to certain embodiments;

[0060] Fig. 9 To illustrate that according to certain examples two prepregs or cores comprising a compounded flame retardant material (or two or more different flame retardant materials) are bonded to each other via skin layers and include another skin layer disposed on one of the skin layers;

[0061] Fig.10 To illustrate an illustration of a strip of material disposed on a core layer according to certain embodiments;

[0062] Fig.11 is a block diagram of a method for preparing a prepreg or core comprising a compounded flame retardant material (or two or more different flame retardant materials) according to certain examples; and

[0063] Fig.12is a block diagram of another method for preparing a prepreg or core comprising a compounded flame retardant material (or two or more different flame retardant materials) according to certain examples.

[0064] It will be recognized by those skilled in the art that, in view of the interests of the present disclosure, certain dimensions or features in the figures may have been enlarged, deformed, or shown in other unconventional or disproportionate ways to provide a more user-friendly diagrammatic style. The description in the figure does not specify a specific thickness, width, or length, and the relative size of the figure components is not intended to limit the size of any component in the figure. Where dimensions or values ​​are specified in the following description, the dimensions or values ​​are provided for illustrative purposes only. In addition, shading certain parts of the figure does not mean that a specific material or arrangement is required, and even if different components in the figure may include shading for the purpose of distinction, different components may also include the same or similar materials if necessary. In some cases, for illustrative purposes, a core layer comprising a mixed flame retardant material (or two or more different flame retardant materials) is shown as including whiskers or points. Unless otherwise specified in the context of describing the particular figure, the arrangement of whiskers and points is not intended to imply any specific distribution. DETAILED DESCRIPTION

[0065] Certain embodiments are described below with reference to singular and plural terms to provide a more user-friendly description of the technology disclosed herein. These terms are used for convenience purposes only and are not intended to limit prepregs, cores, articles, composites, and other subject matter to include or exclude certain features unless otherwise indicated as present in or excluded from a particular embodiment described herein.

[0066] In some cases, thermoplastic composite articles are often molded or processed into various shapes to provide final formed parts or articles. The exact final article formed may depend on a specific application. For example, in some cases, the prepreg and core described herein may be provided in sheet form, and then the sheet may be molded, trimmed or formed into a desired geometry or structure. In some cases, the sheet may be processed to provide office appliances or indoor building products, including but not limited to compartments, wall coverings (e.g., wall coverings that may be adhered to pilasters or cover existing drywall) or other materials adhered to pilasters, seat backs, seat frames, top plates, ceiling panels, floors or other articles that may be used in office or building applications. In other cases, composite articles may be used in exterior automotive applications, including floor shields, skid plates, etc. As noted in more detail below, composite articles may be prepared in many different ways, but in most cases, composite articles are non-extruded composite articles to provide porous prepregs or core layers.

[0067] In some configurations described herein, the presence of a compounded flame retardant material in a thermoplastic prepreg or thermoplastic core allows the prepreg or core to provide flame retardancy to at least some extent. For example, the prepreg or core may meet the Class A standard of the ASTM E84 test dated 2009 and entitled "Standard Test Method for Surface Burning Characteristics of Building Materials". For example, a specific compounded flame retardant material selected for use in a core layer may provide an article that meets the ASTM E84 Class A or Class B requirements in the form of a prepared state article (e.g., without any molding) or in the form of a molded article (if required). Class A articles are different from Class B articles because the flame spread index of Class A articles is about 0-25, while the flame spread index of Class B articles is about 26-75. In some cases, enough compounded flame retardant material is present in the final prepreg or core to meet the Class A standard according to the ASTM E84 test dated 2009.

[0068] The combination of EG material and one or more other flame retardant materials such that the composite article meets SAE J369 method (November 2007 revision). In this specification and claims, this test method is referred to as the SAE flammability test or the SAE self-extinguishing test in some cases. In some examples, less than 10% by weight of EG material, less than 9% by weight of EG material, less than 8% by weight of EG material, less than 7% by weight of EG material, less than 6% by weight of EG material, or even less than 5% by weight of EG material may be present in the prepreg or core layer and enough of another flame retardant material is present in the prepreg or core layer to make the composite article meet or pass the non-oil immersed and oil immersed SAE flammability tests.

[0069] In some embodiments, the exact material used as the compounded flame retardant material may vary depending on the desired overall properties of the prepreg or core and / or the method for preparing the prepreg or core. Compounded flame retardant materials typically include a flame retardant or material that has been compounded with another material. For example, a compounded flame retardant material may include a flame retardant that has been compounded with one or more thermoplastic or thermosetting materials. In the case where the prepreg or core comprises a combination of a thermoplastic material and reinforcing fibers, a material present in the compounded flame retardant material may also be a thermoplastic material. The initial thermoplastic material in the prepreg or core may be the same as the thermoplastic material present in the compounded flame retardant or may be different. In some cases where a thermoplastic material is present in the compounded flame retardant material, the thermoplastic material of the compounded flame retardant material may include one or more of the following: polyethylene, polypropylene, polystyrene, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polybutylene tetrachloroacetate, and polyvinyl chloride (plasticized and unplasticized) and blends of these materials with each other or with other polymeric materials. Other suitable thermoplastic materials for use in the compounded flame retardant material include, but are not limited to, polyarylene ether, polycarbonate, polyester carbonate, thermoplastic polyester, polyimide, polyetherimide, polyamide, acrylonitrile-butyl acrylate-styrene polymer, amorphous nylon, polyarylene ether ketone, polyphenylene sulfide, polyarylene sulfone, polyether sulfone, liquid crystal polymer, commercially known as Poly(1,4-phenylene) compounds, high heat polycarbonates (such as Bayer's PC), high temperature nylon and silicone and alloys and blends of these materials with each other or with other polymeric materials. In some cases herein, a compounded flame retardant material comprising a thermoplastic material compounded with a flame retardant material is referred to as a compounded flame retardant thermoplastic material.

[0070] In certain embodiments, the flame retardant used in the mixed flame retardant material may include many different materials, including organic and inorganic flame retardant materials. In certain configurations, the flame retardant of the mixed flame retardant material may include an inorganic material or an inorganic salt. For example, restrictions on hazardous substances (RoHS) may require that the flame retardant material be selected as an inorganic salt that is substantially free of (or free of) any halide. In some embodiments, the flame retardant material may include a combination of a Group II metal or a Group III metal and one or more anions. For example, the flame retardant material of the mixed flame retardant material may include a beryllium salt, a calcium salt, a magnesium salt or other Group II metal salts. In some embodiments, the Group II metal of the mixed flame retardant material can exist in the form of a hydroxide material. For example, the flame retardant material can exist in the form of beryllium hydroxide, calcium hydroxide, magnesium hydroxide or other Group II metal hydroxides. In other cases, the flame retardant material of the mixed flame retardant material may include an aluminum salt, a gallium salt, an indium salt or other Group III metal salts. In some embodiments, the Group III metal salt of the mixed flame retardant material can exist in the form of a hydroxide material. For example, the flame retardant material may be in the form of aluminum hydroxide or gallium hydroxide or other Group III metal hydroxides.

[0071] In other configurations, the inorganic material in the form of a mixed flame retardant material may include one or more transition metal salts that can act as flame retardants. For example, a transition metal that can form a divalent cation in solution can be combined with one or more anions and used as a flame retardant. In some cases, the transition metal salt can exist in a non-halide form, such as a fluoride, chloride, bromide or iodide salt, to avoid the release of toxic gases when the prepreg or core undergoes combustion. In some configurations, the transition metal salt can exist, for example, in the form of a hydroxide.

[0072] The exact amount of the compounded flame retardant material used in the prepreg and the core can vary depending on what other materials are present, but the compounded flame retardant material is typically present in a weight percentage lower than the main amount of the prepreg or the core, such as a compounded flame retardant material typically present in 50% by weight or less by the weight of the prepreg or the core. In some cases, the compounded flame retardant material is present in excess of a minute amount to provide flame retardancy for the prepreg or the core. For example, the compounded flame retardant material can be present in 30% by weight or more, 35% by weight or more, 40% by weight or more or even 45% by weight or more by the weight of the prepreg or the core. It can be commercially available from Washington Penn Plastic Co. (Washington, PA) or can be prepared by mixing a suitable flame retardant material with a suitable thermoplastic material or other material to prepare an illustrative compounded flame retardant material. For example, an extrusion process can be used to mix a flame retardant material (such as a Group II hydroxide) with another material (such as a thermoplastic material). In some cases, a thermoplastic material is added to an extruder and melted. The molten polymer can be pushed or propelled into the barrel, and then the flame retardant material is added to the barrel. The resulting mixture is pushed forward, which has the effect of mixing the flame retardant material into the molten thermoplastic material. The resulting mixture can then be cooled to form a solid material, such as particles or pellets. The specific ratio of the flame retardant material to the thermoplastic material can vary. For example, the ratio of flame retardant material: other materials can be changed from 1:1, 2:1, 3:1, 4:1, 5:1, 1:5, 1:4, 1:3 to 1:2. In the case where the mixed flame retardant material includes a combination of an inorganic flame retardant salt and a thermoplastic material, the inorganic salt is typically present in the mixed flame retardant material in a relatively high amount. For example, the ratio of inorganic salt:thermoplastic material can be about 2: 1, 3: 1, 3: 2, 5: 2, 7: 2, 4: 3, 5: 3, 7: 3, 8: 3, 5: 4, 7: 4, 9: 4, 11: 4, 6: 5, 7: 5, 8: 5, 9: 5, 11: 5, 13: 5 or other ratios. However, if desired, the thermoplastic material can be present in the compounded flame retardant material in an equal amount by weight or can even be present in the compounded flame retardant material in an amount higher by weight than the flame retardant material.

[0073] Depending on the particular method used to prepare the prepreg or core, the compounded flame retardant material may be ground, filtered, sized, or otherwise processed before being added to the other materials of the prepreg or core. In some cases where thermoplastic particles are used in the prepreg or core, the average particle size of the compounded flame retardant material may be approximately the same as the average particle size of the thermoplastic material. In other configurations, the average particle size of the compounded flame retardant material may be less than or greater than the average particle size of the thermoplastic material used in the prepreg or core.

[0074] In some cases, two or more different flame retardants can be used in combination with thermoplastic materials and reinforcing fibers. If necessary, one of the flame retardants can be a mixed flame retardant as described herein. For example, in some cases, one of the flame retardants can include expandable graphite (EG) materials, and another flame retardant can include a Group II or Group III metal salt. For example, the EG material can be combined with a beryllium salt, a calcium salt, a magnesium salt, or other Group II metal salts or with an aluminum salt, a gallium salt, an indium salt, or other Group III metal salts. In other examples, the EG material can be used in combination with a Group II or Group III metal hydroxide. For example, the EG material can be combined with beryllium hydroxide, calcium hydroxide, magnesium hydroxide, or other Group II metal hydroxides or with aluminum hydroxide or gallium hydroxide or other Group III metal hydroxides. Non-EG flame retardant materials can exist in a mixed form or a non-mixed form as needed. For example, the EG material can be used in combination with an MDH mixed with PP or an aluminum hydroxide (ATH) mixed with PP. In other configurations, EG materials can be used together with natural MDH or natural ATH. Without wishing to be limited by any particular theory, by using a combination of non-EG flame retardants and EG flame retardants, the total amount of EG materials can be reduced while still providing the desired flame retardancy. The exact type of expandable graphite material used in the prepreg can depend on many factors, including, for example, the desired flame retardancy level. Illustrative commercially available expandable graphite materials can be purchased from Nyacol Nano Technologies, Inc. (Ashland, MA) and include, for example, expandable graphite materials of grades 35, 200, 249, 250, 251, KP251 and 351. Additional expandable graphite materials can be purchased commercially from Graftech International (Lakewood, OH). Expandable graphite materials can generally be prepared by acidifying graphite ore. Acidification causes an intercalation process, such as where sulfuric acid acts as an intercalation agent. The solution can then be neutralized to provide a series of sheet layers of hexagonal carbon-carbon bonded materials. The layer is generally planar and interacts with an additional hexagonal carbon-carbon layer to provide a layered sheet structure. The layered sheet structure can be combined together by covalent bonding or electrostatic interaction (or both) between the sheets. If necessary, a suitable oxidant can be used to oxidize the expandable graphite material to form graphene oxide. As noted herein, the expandable graphite material can exist in many forms, including flake form, particle form or other forms. In some cases, the expandable graphite material exists in particle form and can include, for example, an average particle size of at least 300 microns. In some configurations, the form of the EG material is selected to be identical to the form of a non-EG flame retardant, such as both can be used in flake form.

[0075] In certain configurations, the articles described herein may include prepregs or core layers. Although it is not desired to be limited by any particular theory, prepregs are generally not cores of fully formed or processed types. For example, a partially formed layer comprising a thermoplastic material, a plurality of fibers, and a blended flame retardant material (or a combination of EG materials and different flame retardants) is collectively referred to as a prepreg, and a fully formed layer comprising a thermoplastic material, a plurality of fibers, and a blended flame retardant material (or a combination of EG materials and different flame retardants) is collectively referred to as a core or core layer. As noted herein, although the core may be considered as formed or cured, the core may still be bonded to one or more skins to change the overall properties of the composite article including the core layer. The following description mentions both prepregs and cores, and if desired, the materials (and their amounts and properties) used in conjunction with the prepregs may also be used in the core.

[0076] In some cases, the prepregs, cores and articles described herein are porous or permeable materials comprising an open-cell structure (e.g., voids). The presence of such open-cell structures formed by thermoplastic materials makes it more difficult for prepregs, cores and articles to meet flame retardancy standards. By including a combination of a mixed flame retardant material with a thermoplastic material and fiber, prepregs, cores and articles can be flame retardant and meet the Class A requirements of ASTM E84 test. For example, as tested by ASTM E84, the flame spread index of an article comprising a porous core layer containing multiple reinforcing fibers, a thermoplastic material and an effective amount of a mixed flame retardant material can be 25 or less. In some instances, by using a combination of EG materials and different flame retardants (which may or may not be mixed with another material), a prepreg or core can meet the SAE flammability test of non-oil-immersed and oil-immersed samples. If necessary, the flame retardant material or mixed flame retardant material can be evenly dispersed in the void space of the porous core layer or can be differentially distributed, wherein more flame retardant materials are present in one or more regions or closer to one or more surfaces of the core layer. As noted below, if desired, a skin layer or other material may also be placed on the porous core layer and may be selected to further enhance flame retardancy. In some cases, the compounded flame retardant material and the amount of compounded flame retardant material in the core layer may be selected so that the final prepared article (e.g., an article with a skin layer) meets the ASTM E84 Class A requirements. In other cases, the flame retardant material and the amount of flame retardant material in the core layer may be selected so that the final prepared article (e.g., an article with a skin layer) meets the SAE flammability test. As noted herein, articles that meet one or more of the E84 Class A requirements or the SAE flammability test may be used in many different applications, including, for example, as recreational vehicle panels, office cubicle walls, building panels or similar materials that can replace drywall, roof panels, structural panels, floors; in automotive applications, such as interior panels, floor shields, engine hoods, etc.; in aerospace applications, as interior aircraft wall panels, aircraft floors; or as other construction, automotive or aerospace applications.

[0077] In some configurations, a porous prepreg comprising one or more thermoplastic materials and a plurality of fibers (which together provide an open-cell structure, such as a void space) can be prepared. In some configurations, a flame retardant material (such as an EG material, a Group II metal salt, a Group III metal salt, a mixed flame retardant material, etc.) can be loaded into the void space in a certain manner, wherein the flame retardant material resides (at least partially) in the void space formed by the intersecting fibers that can be held in place by the thermoplastic material. In some cases, thermoplastic materials and / or fibers can be selected so that they are generally inert or do not react with the flame retardant material. In some instances, the flame retardant material may not be covalently bonded to the thermoplastic material and / or the fiber, but there may be association between any charged flame retardant material and the thermoplastic material of the porous prepreg. For example, a weak interaction may occur between the flame retardant material and the other components of the prepreg or the core, such as van der Waals'interaction or electrostatic interaction.

[0078] In some instances and with reference to Figure 1, the prepreg 100 is shown as including a thermoplastic material and a plurality of fibers. The prepreg 100 also includes one or more flame retardant materials (shown as points 105 for illustrative purposes) dispersed in the prepreg 100. In some examples, the flame retardant material 105 is a combination of a mixed flame retardant material, an EG material and a Group II salt or a Group III salt, a combination of an EG material and magnesium hydroxide, a combination of an EG material and aluminum hydroxide, and the like. In some cases, the flame retardant material dispersion may be substantially homogeneous or substantially uniform from the first surface 102 to the second surface 104 of the prepreg 100. As described in more detail herein, to achieve such a substantially homogeneous or substantially uniform distribution of one or more flame retardant materials in the prepreg 100, the components of the prepreg 100 may be mixed together to form a dispersion. Mixing may be performed until the dispersion contains a substantially homogeneous or substantially uniform mixture of one or more flame retardant materials, thermoplastic materials, and fibers in the dispersion. The prepreg 100 may then be formed as described herein, for example, by placing the dispersion on a wire screen using a suitable lay-up method. In other configurations, it may be desirable to provide a gradient distribution of one or more flame retardant materials from surface 102 to surface 104 such that more of the one or more flame retardant materials are present on one surface than on the other surface 102, 104. In some embodiments, there is a substantially uniform distribution of flame retardant material in the prepreg 100, and then additional flame retardant material (which may be the same or different) is added to one side of the prepreg 100 to provide a gradient distribution. Such additional flame retardant material may be added directly to the prepreg 100, for example, by spraying a powdered flame retardant material or applying a solution containing the flame retardant material, or may be added by bonding a skin layer, additional prepreg, or other component containing the flame retardant material to the prepreg 100. By way of example and with reference to Figure 2A , showing a first prepreg 210 and a second prepreg 220 disposed on the first prepreg 210. Each of the first prepreg 210 and the second prepreg 220 contains a substantially uniform distribution of flame retardant material, but the amount of flame retardant material by weight in the prepregs 210, 220 is different. However, if desired, only one of the prepregs 210, 220 may contain a flame retardant material and the other prepreg may not contain any flame retardant material or may contain a different flame retardant material. The thermoplastic material of the prepregs 210, 220 may be melted and / or pressed to provide a single prepreg 250 ( Figure 2B ). The result of fusing the prepregs 210, 220 together is a gradient distribution of flame retardant material in the prepreg 250, wherein the amount of flame retardant material near the surface 252 is increased compared to the amount present near the surface 254. The exact overall thickness of the prepreg 250 may vary depending on the conditions used and is Figure 2BNo particular thickness is intended to be implied. Although not shown, a third prepreg similar to prepreg 210 may be bonded to an opposing surface of prepreg 220 to provide a 3-layer prepreg that may be melted to provide a higher amount of flame retardant material near each surface of the composite prepreg. While not wishing to be bound by any particular theory, by varying the amount and / or type of flame retardant material at different depths in the prepreg, enhanced flame retardancy may be provided at the surface of the prepreg, within the interior of the prepreg, or both.

[0079] In other arrangements, the distribution of the flame retardant material in the prepreg may be provided by bonding a skin layer or other material comprising the flame retardant material to the prepreg. Figure 2C , a skin layer 270 comprising a flame retardant material is shown disposed on a prepreg 260 comprising a thermoplastic material, reinforcing fibers, and a flame retardant material. Although not required, the skin layer 270 is typically present at a much lower thickness than the thickness of the prepreg 260. In addition, there is typically a discernible interface between the skin layer 270 and the interface 260, however, as shown in the combination Figure 2B As described, the bonding of two prepregs to each other generally does not produce any discernible interface in the final bonded prepreg 250. In other cases, the skin layer 270 may be melted into the prepreg 260 to bond the skin layer 270 and the prepreg 260, so that the bonded skin layer / prepreg composite material does not have any basic interface. If necessary and as described in more detail below, another skin layer that may or may not contain a flame retardant material may also be bonded to the prepreg on the opposite side of the skin layer 270. Although the exact composition of the skin layer 270 may vary, in some cases, the skin layer 270 itself may impart certain flame retardancy to the total prepreg. The skin layer 270 may be an open structure skin layer, for example, including an open cell structure, or may be a closed structure skin layer. For example, the skin layer 270 may include an open structure to allow flames to enter the prepreg 260, where it may contact the flame retardant material.

[0080] In some configurations, the thermoplastic material of the prepreg can exist in fiber form, particle form, resin form or other suitable forms. In some cases, the thermoplastic material used in the prepreg can exist in particle form and the average particle size is substantially the same as the average particle size of the flame retardant material. Although it is not desired to be limited by any particular scientific theory, by matching the particle size of the thermoplastic material and the flame retardant material, enhanced prepreg processing can be achieved, including, for example, the flame retardant material load increased in the prepreg. In some cases, the average particle size of the flame retardant material and the average particle size of the thermoplastic material can be up to about 5% to about 10% and enhanced processing can still be achieved. In some configurations, the average particle size of the thermoplastic material and the flame retardant material in the prepreg can differ by about 50 microns to about 100 microns. In some configurations, the average particle size of the flame retardant material is at least 50% of the average particle size of the thermoplastic material particles to provide enhanced processing. In other cases, a flame retardant material having an average particle size roughly the same as the average particle size of the thermoplastic material can exist together with a flame retardant material having an average particle size different from the average particle size of the thermoplastic material. Although the average particle size of the flame retardant material may be different, the chemical composition of the flame retardant material may be the same or may be different. In yet other configurations, there may be two or more thermoplastic materials with different average particle sizes. If desired, there may be two flame retardant materials having an average particle size substantially the same as the average particle size of the thermoplastic material. The two flame retardant materials may be chemically the same or may be chemically different. Similarly, the thermoplastic material may be chemically the same (but with different average particle sizes) or may be chemically different. In some cases, the initial or natural thermoplastic material used to prepare the prepreg may be the same thermoplastic material as that present in the compounded flame retardant material. In other cases, the compounded flame retardant material may include two or more thermoplastic materials, wherein one of the thermoplastic materials is the same as the initial thermoplastic material used to prepare the prepreg.

[0081] In certain embodiments, the prepreg 100 includes a large amount of open-cell structure so that there is void space in the prepreg. For example, the prepreg may include 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 cases, the prepreg contains a porosity or void content of greater than 0% (e.g., not fully consolidated) to about 95%. Unless otherwise specified, reference to a prepreg containing a certain void content or porosity is based on the total volume of the prepreg, and is not necessarily the total volume of the prepreg plus any other material or layer combined with the prepreg.

[0082] In certain embodiments, the high porosity present in the prepreg allows the flame retardant material to be captured in the pores of the prepreg and / or to be captured as a coating on the thermoplastic material. For example, the flame retardant material can be present in the void space in a non-covalently bonded manner. The presence of the flame retardant material in the void space can provide enhanced flame retardancy. The flame retardant material can also be applied to the surface of the prepreg to provide enhanced flame retardancy.

[0083] In certain embodiments, the thermoplastic material of the prepreg described herein may at least partially comprise one or more of the following: polyethylene, polypropylene, polystyrene, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polybutylene tetrachloroate, and polyvinyl chloride (plasticized and unplasticized) and blends of these materials with each other or with other polymeric materials. Other suitable thermoplastics include, but are not limited to, polyarylene ethers, polycarbonates, polyester carbonates, thermoplastic polyesters, polyimides, polyetherimides, polyamides, acrylonitrile-butyl acrylate-styrene polymers, amorphous nylons, polyarylene ether ketones, polyphenylene sulfides, polyarylene sulfones, polyether sulfones, liquid crystal polymers, commercially known as Poly(1,4-phenylene) compounds, high heat polycarbonates (such as Bayer's PC), high temperature nylon and silicone and alloys and blends of these materials with each other or with other polymeric materials. In the case where the mixed flame retardant material also includes a thermoplastic material mixed with the flame retardant material, the thermoplastic material of the mixed flame retardant material can be the same material as the material of the initial thermoplastic material selected as the prepreg. The initial thermoplastic material for forming the prepreg 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 in, for example, U.S. Publication Nos. 20130244528 and US20120065283. The exact amount of the thermoplastic material present in the prepreg can vary and the illustrative amount is in the range of about 20% by weight to about 80% by weight.

[0084] In certain examples, the fibers of the prepregs described herein may include glass fibers, carbon fibers, graphite fibers, synthetic organic fibers (particularly high modulus organic fibers, such as para- and meta-aramid fibers, nylon fibers, polyester fibers, or any of the high melt flow index resins described herein as suitable for use as fibers), natural fibers (such as sisal, jute, flax, coir fibers, kenaf, and cellulose fibers), mineral fibers (such as basalt, mineral wool (e.g., rock wool or slag wool), wollastonite, alumina silica, etc., or mixtures thereof), metal fibers, metalized natural and / or synthetic fibers, ceramic fibers, yarn fibers, or mixtures thereof. In some embodiments, any of the above fibers may be chemically treated prior to use to provide desired functional groups or to impart other physical properties to the fibers, for example, they may be chemically treated to allow them to react with thermoplastic materials, compounded flame retardant materials, or both. Alternatively, the flame retardant material may be reacted with the thermoplastic material of the prepreg to provide a derived thermoplastic material, which is then mixed with the fibers. The fiber content in the prepreg may be about 20% to about 90% by weight of the prepreg, more particularly about 30% to about 70% by weight of the prepreg. Typically, the fiber content of the composite article including the prepreg varies between about 20% to about 90% by weight of the composite, more particularly about 30% to about 80% by weight (e.g., about 40% to about 70% by weight). The specific size and / or orientation of the fiber used may depend at least in part on the polymer material used and / or the desired resulting prepreg properties. In view of the benefits of the present disclosure, a person skilled in the art will readily select suitable additional fiber types, fiber sizes, and amounts. In a non-limiting illustration, the fibers dispersed in the thermoplastic material to provide the prepreg generally have a diameter greater than about 5 microns, more particularly about 5 microns to about 22 microns, and a length of about 5 mm to about 200 mm; more particularly, the fiber diameter may be about microns to about 22 microns and the fiber length may be about 5 mm to about 75 mm. In some configurations, the flame retardant material may exist in the form of fibers. For example, the prepreg, core or composite may include a thermoplastic material, reinforcing fibers, and fibers comprising a compounded flame retardant material or fibers comprising an EG material. The flame retardant fibers may include any one or more of the flame retardant materials described herein, such as polypropylene fibers compounded with a hydroxide material, which are then extruded and cut into fibers using a suitable die or other device; or a mixture of an EG material and polypropylene fibers compounded with a hydroxide material, which are then extruded and cut into fibers using a suitable die or other device.

[0085] In some configurations, the prepreg may be substantially halogen-free or halogen-free prepreg to meet the requirements of restrictions on hazardous substances in certain applications. In other cases, the prepreg may include a halogenated flame retardant (which may be present in a flame retardant material or may be added outside a flame retardant material), such as a halogenated flame retardant comprising one or more of F, Cl, Br, I and At or a compound comprising such a halogen, such as tetrabromobisphenol A polycarbonate or a monohalogen-, dihalogen-, trihalogen- or tetrahalogen-polycarbonate. In some cases, the thermoplastic material used in the prepreg and the core may include one or more halogens to impart certain flame retardancy without adding another flame retardant. For example, the thermoplastic material of the mixed flame retardant material may also be halogenated in addition to being mixed with the flame retardant material, or the initial thermoplastic material may be halogenated. In the presence of a halogenated flame retardant, the flame retardant is ideally present in a flame retardant amount, which may vary according to the other components present. For example, in the case of a halogenated flame retardant in addition to a mixed flame retardant material, the halogenated flame retardant can be present in an amount of about 0.1 wt % to about 15 wt % (based on the weight of the prepreg), more particularly about 1 wt % to about 13 wt % (e.g., about 5 wt % to about 13 wt %). If desired, two different halogenated flame retardants can be added to the prepreg. In other cases, a non-halogenated flame retardant can be added, such as a flame retardant comprising one or more of N, P, As, Sb, Bi, S, Se and Te. In some embodiments, the non-halogenated flame retardant may include a phosphating material, so the prepreg may be more environmentally friendly. In the case of a non-halogenated or substantially halogen-free flame retardant, the flame retardant is ideally present in a flame retardant amount, which may vary according to the other components present. For example, a substantially halogen-free flame retardant can be present in an amount of about 0.1% to about 15% by weight (based on the weight of the prepreg), more particularly about 1% to about 13% by weight (e.g., about 5% to about 13% by weight based on the weight of the prepreg). If desired, two different substantially halogen-free flame retardants can be added to the prepreg. In some cases, the prepreg described herein may include a combination of one or more halogenated flame retardants and one or more substantially halogen-free flame retardants. In the presence of two different flame retardants, the combination of these two flame retardants can be present in a flame retardant amount, which can vary according to the presence of other components. For example, the total weight of the flame retardant present (except any mixed flame retardant material) can be about 0.1% to about 20% by weight (based on the weight of the prepreg), more particularly about 1% to about 15% by weight, such as about 2% to about 14% by weight based on the weight of the prepreg. The flame retardants used in the prepregs described herein may be added to the mixture comprising the thermoplastic material and the fibers (before the mixture is disposed on a wire screen or other processing component) or may be added after the prepreg is formed.

[0086] In certain configurations, the articles described herein may include a porous core. In certain examples, the porous core comprises one or more thermoplastic materials and a plurality of fibers, which may be held in place by a shaped thermoplastic material in a web or mesh structure to provide a plurality of open cells, void spaces, or a web in the core. In some cases, the flame retardant material may be present in the void spaces of the core, such as in the open cells of a web formed by reinforcing fibers being bonded together by the thermoplastic material; or may be present on the fibers of the core; or both. In certain configurations, a porous core similar to Figure 1 The core of the prepreg. The core includes a flame retardant material that is generally dispersed throughout the core. In some cases, the flame retardant material dispersion may be substantially homogeneous or substantially uniform from the first surface of the core to the second surface. As described in more detail herein, in order to achieve such substantially homogeneous or substantially uniform distribution of the flame retardant material in the core, the components of the core may be mixed together to form a dispersion before forming the core. Mixing may be performed until the dispersion contains a substantially homogeneous or substantially uniform mixture of one or more flame retardants, thermoplastic materials, and fibers in the dispersion. The core may then be formed by, for example, placing the dispersion on a wire screen using a suitable laying method and then pressing and / or curing the thermoplastic material of the core as described herein. In other configurations, it may be necessary to provide a gradient distribution of one or more flame retardants from one surface of the core to another surface of the core. In some configurations, there is a substantially uniform distribution of flame retardants in the core, and then additional flame retardants are added to one side of the core to provide a gradient distribution. Such additional flame retardant materials may be added directly to the core, for example, by spraying or coating or by using a solution containing a flame retardant material, or may be added by bonding a skin layer, an additional prepreg or a core or another component containing a flame retardant material to the core. For example, a first core and a second core disposed on the first core may provide a composite article. Each of the cores may contain a substantially uniform distribution of flame retardant materials, but the amount and / or type of flame retardant materials in the two cores may be different, such as the load rate may be different or the flame retardant material itself may be different. However, if desired, only one of the cores may contain a flame retardant material and the other core may not contain materials other than thermoplastic materials and reinforcing fibers. The thermoplastic material of the core may be melted to provide a single combined core including materials from the two cores. The result of the core melting is a composite core with a gradient distribution of flame retardant materials. In other configurations, the distribution of flame retardant materials in the core may be provided by bonding a skin layer or other material containing a flame retardant material to the core. In other cases, the skin layer may be melted into the core to bond the skin layer and the core, so that the bonded skin layer / core composite material does not have any basic interface. If desired and as described in more detail below, another skin layer, which may or may not contain a flame retardant material, may also be bonded to the core on the opposite side of the first skin layer.

[0087] In some configurations, the thermoplastic material of the core can be used in the core in the form of fibers, particles, resins or other suitable forms. In some instances, the thermoplastic material used in the core can exist in the form of particles and the average particle size is substantially the same as the average particle size of the flame retardant material. By matching the particle size of the thermoplastic material and the flame retardant material, the processing of the core is enhanced, including, for example, increasing the retention of the flame retardant material in the core, which can play a role in increasing the flame retardancy level of the core. In some cases, the average particle size of the flame retardant material and the average particle size of the thermoplastic material can be up to about 5% to about 10% and enhanced processing can still be achieved. In some configurations, the average particle size of the thermoplastic material and the flame retardant material in the core can be within the range of about 50 microns to about 900 microns. In other cases, the flame retardant material having an average particle size roughly the same as the average particle size of the thermoplastic material can exist together with the flame retardant material having an average particle size different from the average particle size of the thermoplastic material. Although the average particle size of the flame retardant material can be different, the chemical composition of the flame retardant material can be the same or different. In yet other configurations, there may be two or more thermoplastic materials with different average particle sizes. If desired, there may be two flame retardant materials in the core having an average particle size substantially the same as the average particle size of the two thermoplastic materials. The two flame retardant materials may be chemically identical or may be chemically different. Similarly, the thermoplastic materials may be chemically identical (but with different average particle sizes) or may be chemically different.

[0088] In certain embodiments, the core generally comprises a substantial amount of open cell structure such that void space exists in the core. For example, the core layer may comprise 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%, 5-30%, 5-40%, 5-50%, 5-60%, 5-70%, 5-80%, 5-90%, 5-95%, 10-50%, 10-60%, 10-70%, 10-80%, 10-9 In some cases, the core comprises a porosity or void content of greater than 0% (e.g., not fully consolidated) to about 95%. Unless otherwise stated, reference to a core comprising a certain void content or porosity is based on the total volume of the core, and is not necessarily the total volume of the core plus any other material or layer combined with the core. The porosity of the core may be the same or may be different than that of the prepreg. For example, in many cases, the prepreg is formed into a core by passing the prepreg through a set of rollers or by pressing one surface of the prepreg. In such cases, the porosity of the core may be different from the porosity of the prepreg, for example, may be lower. In some cases, the porosity of the core is intentionally selected to be less than that of a similar prepreg to increase the lofting capacity of the core into the final formed article or product.

[0089] In certain embodiments, the high porosity present in the core allows the flame retardant to be captured within the pores of the core. For example, the flame retardant material from the compounded flame retardant material can be present in the void space in a non-covalently bonded manner. In other cases, the flame retardant material can be coated onto the reinforcing fibers present in the core.

[0090] In certain embodiments, the thermoplastic material of the core described herein may at least partially comprise one or more of the following: polyethylene, polypropylene, polystyrene, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polybutylene tetrachloroate, and polyvinyl chloride (plasticized and unplasticized) and blends of these materials with each other or with other polymeric materials. Other suitable thermoplastics include, but are not limited to, polyarylene ethers, polycarbonates, polyester carbonates, thermoplastic polyesters, polyimides, polyetherimides, polyamides, acrylonitrile-butyl acrylate-styrene polymers, amorphous nylons, polyarylene ether ketones, polyphenylene sulfides, polyarylene sulfones, polyether sulfones, liquid crystal polymers, commercially known as Poly(1,4-phenylene) compounds, high heat polycarbonates (such as Bayer's PC), high temperature nylon and silicone and alloys and blends of these materials with each other or with other polymeric materials. The thermoplastic material for forming the core 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 in, for example, U.S. Publication Nos. 20130244528 and US20120065283. The exact amount of thermoplastic material present in the core can vary and the illustrative amount is in the range of about 20 wt % to about 80 wt %. As mentioned in conjunction with the prepreg, the thermoplastic material used to prepare the core may include the same or identical thermoplastic material as that present in the compounded flame retardant material.

[0091] In certain examples, the fibers of the core described herein may include glass fibers, carbon fibers, graphite fibers, synthetic organic fibers (particularly high modulus organic fibers, such as para- and meta-aramid fibers, nylon fibers, polyester fibers, or any of the high melt flow index resins described herein as suitable for use as fibers), natural fibers (such as sisal, jute, flax, coconut shell fibers, kenaf, and cellulose fibers), mineral fibers (such as basalt, mineral wool (e.g., rock wool or slag wool), wollastonite, alumina silica, etc., or mixtures thereof), metal fibers, metallized natural and / or synthetic fibers, ceramic fibers, yarn fibers, or mixtures thereof. In some embodiments, any of the above fibers may be chemically treated prior to use to provide desired functional groups or to impart other physical properties to the fibers, for example, they may be chemically treated to react with thermoplastic materials, flame retardant materials, compounded flame retardant materials, or both. The fiber content in the core may be from about 20% to about 90% by weight of the core, more particularly from about 30% to about 70% by weight of the core. The specific size and / or orientation of the fibers used may depend at least in part on the polymer material used and / or the desired resulting core properties. In view of the benefit of this disclosure, one of ordinary skill in the art will readily select suitable additional fiber types, fiber sizes, and amounts. In a non-limiting illustration, the fibers dispersed in the thermoplastic material to provide the core typically have a diameter greater than about 5 microns, more particularly about 5 microns to about 22 microns, and a length of about 5 mm to about 200 mm; more particularly, the fiber diameter may be about 1 micron to about 22 microns and the fiber length may be about 5 mm to about 75 mm.

[0092] In some cases, the core can be a core that is substantially halogen-free or halogen-free to meet the requirements of restrictions on hazardous substances in certain applications. In other cases, the core can include a halogenated flame retardant, such as a halogenated flame retardant comprising one or more of F, Cl, Br, I and At or a compound comprising such halogen, for example tetrabromobisphenol A polycarbonate or a monohalogen-, dihalogen-, trihalogen- or tetrahalogen-polycarbonate. If desired, the halogen group may exist or may exist on a thermoplastic material or may be added separately from other materials used to prepare the core because of including a blended, halogenated flame retardant. In some cases, the initial thermoplastic material used in the core may include one or more halogens to impart certain flame retardancy without adding another flame retardant. In the presence of a halogenated flame retardant, the flame retardant is ideally present in a flame retardant amount that can vary according to other components present. The presence of a combination of an EG material and another flame retardant material or the presence of a mixed flame retardant material can allow the use of a relatively low amount of halogenated flame retardants, which can work synergistically with flame retardants from other flame retardants. For example, a halogenated flame retardant can be present in an amount of about 0.1 wt % to about 15 wt % (based on the weight of the core), more particularly about 1 wt % to about 13 wt % (e.g., about 5 wt % to about 13 wt %). If desired, two different halogenated flame retardants can be added to the core. In other cases, a non-halogenated flame retardant can be added, such as a flame retardant comprising one or more of N, P, As, Sb, Bi, S, Se and Te. In some embodiments, a non-halogenated flame retardant can include a phosphating material, so the core can be more environmentally friendly. In the presence of a non-halogenated or substantially halogen-free flame retardant, the flame retardant is ideally present in a flame retardant amount, which can vary according to other components present. For example, substantially halogen-free flame retardants can be present in an amount of about 0.1% to about 15% by weight (based on the weight of the core), more particularly about 1% to about 13% by weight (e.g., about 5% to about 13% by weight based on the weight of the core). If desired, two different substantially halogen-free flame retardants can be added to the core. In some cases, the core described herein may include a combination of one or more halogenated flame retardants and one or more substantially halogen-free flame retardants. In the presence of two different flame retardants, the combination of these two flame retardants can be present in a flame retardant amount, which can vary according to the presence of other components. For example, the total weight of the flame retardant present (except for the weight present due to the flame retardant material) can be about 0.1% to about 20% by weight (based on the weight of the core), more particularly about 1% to about 15% by weight, for example, about 2% to about 14% by weight based on the weight of the core. The flame retardants used in the cores described herein can be added to the mixture comprising thermoplastic material and fibers (before the mixture is disposed on a wire screen or other processing component) or can be added after the core is cured, such as by dipping the core in the flame retardant or spraying the flame retardant on the core.

[0093] In certain embodiments, the reinforcing fibers and the initial thermoplastic material of the prepreg and the core can be combined with a compounded thermoplastic flame retardant material to provide a prepreg or core that meets the Class A standard according to ASTM E84 testing. The thermoplastic material from the compounded thermoplastic flame retardant material may include the same material as the initial thermoplastic material or a different thermoplastic material. The compounded thermoplastic flame retardant material may include one or more divalent or trivalent metal salts as a flame retardant material. For example, the compounded thermoplastic flame retardant material may include a Group II metal hydroxide material, which has been compounded with a thermoplastic material such as a polyolefin or other suitable thermoplastic material described herein. In other cases, the compounded thermoplastic flame retardant material may include a Group III metal hydroxide material, which has been compounded with a thermoplastic material such as a polyolefin or other suitable thermoplastic material described herein.

[0094] In some cases, one or more lofting agents may be added to the prepreg or core to allow lofting. For example, lofting agents such as microspheres or expandable graphite materials may be added to the prepreg or core to allow the total thickness of the prepreg or core to be adjusted. Without wishing to be limited by any particular theory, as the prepreg or core is heated, the lofting agent may play a role in increasing the total thickness of the prepreg or core. If necessary, the prepreg or core containing the lofting agent may be pressed to allow the end user to apply heat to expand the prepreg or core thickness to the desired amount. Depending on the end use of the prepreg or core, different types of articles may need to have different total thicknesses. The amount of EG material may be selected to provide the desired lofting capacity and / or the desired flame retardant effect. For example, the level of the EG material may be about 1% by weight to about 5% by weight to provide the desired lofting capacity, and may be used in combination with another flame retardant material so that the EG material and the flame retardant material meet the non-oil-immersed SAE and oil-immersed SAE self-extinguishing tests together.

[0095] In certain embodiments, the prepregs or cores described herein may include one or more skin layers disposed on a surface of the prepreg or core to provide an article. Figure 3, article 300 includes a prepreg or core 310, the core 310 comprising a thermoplastic material, a plurality of fibers, and a blended flame retardant material or a combination of two or more different flame retardant materials, such as a combination of an EG material and a Group II or Group III metal hydroxide. Article 300 includes a first skin layer 320 disposed on the prepreg or core 310. Skin layer 320 may include an open cell structure or a closed cell structure. In certain configurations, skin layer 320 may include, for example, a film (e.g., a thermoplastic film or an elastic film), an inorganic fiberglass (frim), a mesh (e.g., a fiber-based mesh), a foil, a woven fabric, a nonwoven fabric, or exists as an inorganic coating, an organic coating, or a thermosetting coating disposed on the prepreg or core 310. In other cases, skin layer 320 may include a limiting oxygen index greater than about 22 as measured according to ISO 4589, dated 1996. Where a thermoplastic film is present as (or as part of) the surface layer 320, the thermoplastic film may include at least one of: poly(etherimide), poly(etherketone), poly(ether-etherketone), poly(phenylene sulfide), poly(arylene sulfone), poly(ethersulfone), poly(amide-imide), poly(1,4-phenylene), polycarbonate, nylon, and silicone. Where a fiber-based mesh is present as (or as part of) the surface layer 320, the fiber-based mesh may include at least one of: glass fiber, aramid fiber, graphite fiber, carbon fiber, inorganic mineral fiber, metal fiber, metallized synthetic fiber, and metallized inorganic fiber. Where a thermosetting coating is present as (or as part of) the surface layer 320, the coating may include at least one of: unsaturated polyurethane, vinyl ester, phenolic resin, and epoxy resin. In the case where inorganic coating exists as surface layer 320 (or as a part thereof), inorganic coating may include minerals containing cations selected from Ca, Mg, Ba, Si, Zn, Ti and Al or may include at least one of gypsum, calcium carbonate and mortar. In the case where nonwoven fabric exists as surface layer 320 (or as a part thereof), nonwoven fabric may include thermoplastic material, thermosetting adhesive, inorganic fiber, metal fiber, metallized inorganic fiber and metallized synthetic fiber. Prepreg or core 310 may include any one of the materials described herein in conjunction with prepreg and core, such as thermoplastic material, reinforcing fiber and mixed flame retardant material or two or more different flame retardant materials, such as a combination of EG material and Group II or Group III metal hydroxide. If desired, surface layer 320 may also include mixed flame retardant material.

[0096] In certain configurations, the prepregs and cores described herein may be used to provide articles that include skins on each side of the prepreg or core. Figure 4, the article 400 is shown to include a prepreg or core 410, a first skin layer 420 disposed on a first surface of the prepreg or core 410, and a second skin layer 430 disposed on the prepreg or core 410. The prepreg or core 410 may include any of the materials described herein in conjunction with the prepreg and the core, such as a thermoplastic material, a reinforcing fiber, and a blended flame retardant material or a combination of two or more different flame retardant materials, such as an EG material and a group II or group III metal hydroxide. Each of the first skin layer 420 and the second skin layer 430 may be independently selected from a film (e.g., a thermoplastic film or an elastic film), an inorganic fiberglass, a mesh (e.g., a fiber-based mesh), a foil, a woven fabric, a nonwoven fabric, or exists as an inorganic coating, an organic coating, or a thermosetting coating disposed on the prepreg or core 410. In other cases, the skin layer 420 or the skin layer 430 (or both) may comprise a limiting oxygen index greater than about 22 as measured according to ISO 4589 dated 1996. Where a thermoplastic film is present as (or as a portion of) the skin layer 420 or the skin layer 430 (or both), the thermoplastic film may comprise at least one of: poly(etherimide), poly(etherketone), poly(ether-etherketone), poly(phenylene sulfide), poly(arylene sulfone), poly(ethersulfone), poly(amide-imide), poly(1,4-phenylene), polycarbonate, nylon, and silicone. Where a fiber-based web is present as (or as a portion of) the skin layer 420 or the skin layer 430 (or both), the fiber-based web may comprise at least one of: glass fibers, aramid fibers, graphite fibers, carbon fibers, inorganic mineral fibers, metal fibers, metallized synthetic fibers, and metallized inorganic fibers. In the case where the thermosetting coating exists as the surface layer 420 or the surface layer 430 (or both) (or as a part thereof), the coating may include at least one of the following: unsaturated polyurethane, vinyl ester, phenolic resin and epoxy resin. In the case where the inorganic coating exists as the surface layer 420 or the surface layer 430 (or both) (or as a part thereof), the inorganic coating may include a mineral containing a cation selected from Ca, Mg, Ba, Si, Zn, Ti and Al or may include at least one of gypsum, calcium carbonate and mortar. In the case where the nonwoven fabric exists as the surface layer 420 or the surface layer 430 (or both) (or as a part thereof), the nonwoven fabric may include a thermoplastic material, a thermosetting adhesive, an inorganic fiber, a metal fiber, a metallized inorganic fiber and a metallized synthetic fiber. If desired, one or both of the surface layers 420, 430 may include a mixed flame retardant material or two or more different flame retardants, such as a combination of an EG material and a Group II or Group III metal hydroxide. As mentioned herein, one or both of the skin layers 420, 430 may comprise an open cell structure or a closed cell structure.

[0097] In some cases, an article may include a prepreg or core, at least one skin disposed on the prepreg or core, and a decorative or covering layer disposed on the skin. Figure 5, article 500 is shown to include a prepreg or core 510, a skin layer 520 disposed on a first surface of the prepreg or core 510, and a decorative layer 530 disposed on the skin layer 520. The prepreg or core 510 may include any of the materials described herein in conjunction with the prepreg and the core, such as a thermoplastic material, a reinforcing fiber, and a compounded flame retardant material or a combination of two or more different flame retardant materials, such as an EG material and a Group II or Group III metal hydroxide. The skin layer 520 may include, for example, a film (e.g., a thermoplastic film or an elastic film), an inorganic fiberglass, a mesh (e.g., a fiber-based mesh), a foil, a woven fabric, a nonwoven fabric, or exists as an inorganic coating, an organic coating, or a thermosetting coating disposed on the prepreg or core 510. In other cases, the skin layer 520 may include a limiting oxygen index greater than about 22 as measured according to ISO 4589, dated 1996. Where a thermoplastic film is present, the thermoplastic film may comprise at least one of poly(etherimide), poly(etherketone), poly(ether-etherketone), poly(phenylene sulfide), poly(arylene sulfone), poly(ethersulfone), poly(amide-imide), poly(1,4-phenylene), polycarbonate, nylon, and silicone. Where a fiber-based mesh is present, the fiber-based mesh may comprise at least one of glass fibers, aramid fibers, graphite fibers, carbon fibers, inorganic mineral fibers, metal fibers, metallized synthetic fibers, and metallized inorganic fibers. Where a thermosetting coating is present, the coating may comprise at least one of unsaturated polyurethane, vinyl ester, phenolic resin, and epoxy resin. Where an inorganic coating is present, the inorganic coating may comprise a mineral containing cations selected from Ca, Mg, Ba, Si, Zn, Ti, and Al or may comprise at least one of gypsum, calcium carbonate, and mortar. In the case of nonwoven fabric, nonwoven fabric can include thermoplastic material, thermosetting adhesive, inorganic fiber, metal fiber, metallized inorganic fiber and metallized synthetic fiber. Decorative layer 530 can be formed by thermoplastic film, polyolefin, thermoplastic polyester, thermoplastic elastomer, etc. of polyvinyl chloride, for example. Decorative layer 530 can also be a multilayer structure, which includes a foam core formed by, for example, polypropylene, polyethylene, polyvinyl chloride, polyurethane, etc. Fabric can be bonded to the foam core, such as woven fabrics made of natural and synthetic fibers, organic fiber nonwoven fabrics after needle punching, etc., pile fabrics, knitwear, flocking fabrics or other such materials. Fabric can also be bonded to the foam core with thermoplastic adhesives, which include pressure-sensitive adhesives and hot melt adhesives, such as polyamide, modified polyolefin, carbamate and polyolefin. Decorative layer 530 can also be prepared using spunbond, thermal bonding, spunlace, meltblown, wet web forming and / or dry web forming methods. In some configurations, the skin layer 520 may include an open-cell structure or a closed-cell structure.

[0098] In certain configurations, two or more prepregs or cores may be bonded to each other via intervening or intermediate layers such as skin layers. Figure 6 , an article 600 is shown, which includes a prepreg or core 610 bonded to a prepreg or core 630 by an intermediate layer 620. Each of the prepregs or cores 610, 630 may be the same or may be different. In some cases, the thermoplastic material and fiber of the prepregs or cores 610, 630 are the same, but the flame retardant material loading or the type of flame retardant material present in the prepregs or cores 610, 630 is different. In other cases, the type and / or amount of flame retardant material in the prepregs or cores 610, 630 may be the same and one or both of the thermoplastic material and / or fiber may be different, for example, may be chemically different or may be present in different amounts. If desired, one or more suitable additional flame retardants may be present in one or both of the cores 610, 630, such as a halogenated or non-halogenated flame retardant, a combination of an EG material and a Group II or Group III metal hydroxide, a compounded flame retardant material, etc. Although the thickness of the prepreg or core 610, 630 is shown as Figure 6610, 630. In some embodiments, the prepreg or core 610, 630 may be substantially the same, but the thickness of the prepreg or core 610, 630 may vary. In the case of an article that requires a "thick" core, it may be necessary to bond two "thin" core layers to each other through a skin layer 620. In some configurations, one of the prepreg or core 610, 630 may include a lofting agent, such as microspheres. The intermediate layer 620 may take the form of a skin layer as described herein. The skin layer 620 may desirably include an open-cell structure or a closed-cell structure. For example, the intermediate layer 620 may include a film (e.g., a thermoplastic film or an elastic film), an inorganic fiberglass, a mesh (e.g., a fiber-based mesh), a foil, a woven fabric, a nonwoven fabric, or as an inorganic coating, an organic coating, or a thermosetting coating disposed on the prepreg or core 610. In other cases, as measured according to ISO 4589, dated 1996, the layer 620 may include a limiting oxygen index greater than about 22. Where a thermoplastic film is present, the thermoplastic film may include at least one of poly(etherimide), poly(etherketone), poly(ether-etherketone), poly(phenylene sulfide), poly(arylene sulfone), poly(ethersulfone), poly(amide-imide), poly(1,4-phenylene), polycarbonate, nylon, and silicone. Where a fiber-based mesh is present as or in layer 620, the fiber-based mesh may include at least one of glass fiber, aramid fiber, graphite fiber, carbon fiber, inorganic mineral fiber, metal fiber, metalized synthetic fiber, and metalized inorganic fiber. Where a thermosetting coating is present as or in layer 620, the coating may include at least one of unsaturated polyurethane, vinyl ester, phenolic resin, and epoxy resin. Where an inorganic coating is present as or in layer 620, the inorganic coating may include a mineral containing cations selected from Ca, Mg, Ba, Si, Zn, Ti, and Al or may include at least one of gypsum, calcium carbonate, and mortar. In the case where nonwoven fabric exists as layer 620 or exists therein, the nonwoven fabric may include thermoplastic materials, thermosetting adhesives, inorganic fibers, metal fibers, metalized inorganic fibers, and metalized synthetic fibers. Although not shown, the decorative layer may be bonded to any one (or both) of the prepreg or core 610, 630. As noted herein, the decorative layer may be formed, for example, by thermoplastic films of polyvinyl chloride, polyolefins, thermoplastic polyesters, thermoplastic elastomers, etc. The decorative layer may also be a multilayer structure, which includes a foam core formed by, for example, polypropylene, polyethylene, polyvinyl chloride, polyurethane, etc. Fabric may be bonded to the foam core, such as woven fabrics made of natural and synthetic fibers, organic fiber nonwoven fabrics after needle punching, etc., pile fabrics, knitwear, flocking fabrics, or other such materials. Fabric may also be bonded to the foam core with a thermoplastic adhesive, which includes a pressure-sensitive adhesive and a hot melt adhesive, such as polyamide, modified polyolefins, urethanes, and polyolefins.The decorative layer can also be prepared using spunbond, thermal bond, hydroentangled, meltblown, wet laid and / or dry laid methods. If desired, the decorative layer can comprise a closed cell structure or an open cell structure.

[0099] In certain embodiments, two or more prepregs or cores may be bonded to one another, and then a skin layer may be disposed on one surface of the prepreg or core. Figure 7 , an article 700 is shown, which includes a prepreg or core 710 bonded to a prepreg or core 730 and a skin 720 disposed on the core 730. Each of the prepregs or cores 710, 720 may be the same or may be different. In some cases, the thermoplastic material and fiber of the cores 710, 730 are the same, but the flame retardant material loading or the type of flame retardant material present in the cores 710, 730 is different. In other cases, the type and / or amount of flame retardant material in the prepregs or cores 710, 730 may be the same and one or both of the thermoplastic material and / or fiber may be different, for example, may be chemically different or may be present in different amounts. If desired, one or more suitable additional flame retardants may be present in one or both of the prepregs or cores 710, 730, such as a halogenated or non-halogenated flame retardant, a combination of an EG material and a Group II or Group III metal hydroxide, a compounded flame retardant material, etc. Although the thickness of the prepreg or core 710, 730 is shown as Figure 7710, 730. The thickness of the prepreg or core 710, 730 may vary. It may be necessary to use a continuous thin core layer to form a composite article to provide the desired total core thickness. In some configurations, one of the prepreg or core 710, 730 may include a lofting agent, such as an expandable graphite material or microspheres or other materials. The skin 720 may include, for example, a film (e.g., a thermoplastic film or an elastic film), an inorganic fiberglass, a mesh (e.g., a fiber-based mesh), a foil, a woven fabric, a nonwoven fabric, or as an inorganic coating, an organic coating, or a thermosetting coating disposed on the prepreg or core 730. In other cases, the skin 720 may include a limiting oxygen index greater than about 22 as measured according to ISO 4589 dated 1996. In the case where a thermoplastic film is present as or in the surface layer 720, the thermoplastic film may include at least one of the following: poly(etherimide), poly(etherketone), poly(ether-etherketone), poly(phenylene sulfide), poly(arylene sulfone), poly(ethersulfone), poly(amide-imide), poly(1,4-phenylene), polycarbonate, nylon, and silicone. In the case where a fiber-based mesh is present as or in the surface layer 720, the fiber-based mesh may include at least one of the following: glass fiber, aramid fiber, graphite fiber, carbon fiber, inorganic mineral fiber, metal fiber, metallized synthetic fiber, and metallized inorganic fiber. In the case where a thermosetting coating is present as or in the surface layer 720, the coating may include at least one of the following: unsaturated polyurethane, vinyl ester, phenolic resin, and epoxy resin. In the case where an inorganic coating is present as or in the surface layer 720, the inorganic coating may include a mineral containing cations selected from Ca, Mg, Ba, Si, Zn, Ti, and Al or may include at least one of gypsum, calcium carbonate, and mortar. In the case where a nonwoven fabric is present as or in the surface layer 720, the nonwoven fabric may include a thermoplastic material, a thermosetting adhesive, an inorganic fiber, a metal fiber, a metallized inorganic fiber, and a metallized synthetic fiber. Depending on the final configuration of the article 700, the surface layer 720 may be an open-cell surface layer to allow sound energy to pass through the surface layer or may be a closed-cell surface layer to reflect sound energy back into the core 710, 730. Although not shown, a decorative layer may be bonded to the surface of the surface layer 720 or the prepreg or the core 710. As noted herein, the decorative layer may be formed, for example, of a thermoplastic film of polyvinyl chloride, a polyolefin, a thermoplastic polyester, a thermoplastic elastomer, and the like. The decorative layer may also be a multilayer structure including a foam core formed of, for example, polypropylene, polyethylene, polyvinyl chloride, polyurethane, etc. Fabrics may be bonded to the foam core, such as woven fabrics made of natural and synthetic fibers, organic fiber nonwoven fabrics after needle punching, etc., pile fabrics, knitted fabrics, flocked fabrics, or other such materials. Fabrics may also be bonded to the foam core with thermoplastic adhesives, including pressure-sensitive adhesives and hot melt adhesives, such as polyamides, modified polyolefins, urethanes, and polyolefins.The decorative layer may also be prepared using spunbond, thermal bond, hydroentangled, meltblown, wet laid and / or dry laid processes.

[0100] In certain embodiments, two or more prepregs or cores may be bonded to one another, and then a skin layer may be disposed on each surface of the prepreg or core. Figure 8 , an article 800 is shown, which includes a prepreg or core 810 bonded to a prepreg or core 830, a first skin 820 disposed on the core 830, and a second skin 840 disposed on the core 810. Each of the prepregs or cores 810, 830 may be the same or may be different. In some cases, the thermoplastic material and fibers of the prepregs or cores 810, 830 are the same, but the flame retardant material loading or the type of flame retardant material present in the prepregs or cores 810, 830 is different. In other cases, the type and / or amount of flame retardant material in the prepregs or cores 810, 830 may be the same and one or both of the thermoplastic material and / or fiber may be different, for example, may be chemically different or may be present in different amounts. If desired, one or more suitable additional flame retardants may be present in one or both of the prepregs or cores 810, 830, such as halogenated or non-halogenated flame retardants, combinations of EG materials with Group II or Group III metal hydroxides, compounded flame retardant materials, etc. Although the thickness of the prepregs or cores 810, 830 is shown as Figure 8810, 830. The thickness of the prepreg or core 810, 830 may vary. As noted herein, it may be desirable to use two or more core layers bonded to one another rather than a single core layer of increased thickness. In some configurations, one of the prepreg or core 810, 830 may include a lofting agent, such as an expandable graphite material or microspheres or other materials. Each of the surface layers 820, 840 may independently include, for example, a film (e.g., a thermoplastic film or an elastic film), an inorganic fiberglass, a mesh (e.g., a fiber-based mesh), a foil, a woven fabric, a nonwoven fabric, or as an inorganic coating, an organic coating, or a thermosetting coating disposed on the prepreg or core 830. In other cases, the surface layers 820, 840 may independently include a limiting oxygen index greater than about 22, as measured according to ISO 4589, dated 1996. Where a thermoplastic film is present as or in the surface layer 820 or the surface layer 840 (or both), the thermoplastic film may include at least one of poly(etherimide), poly(etherketone), poly(ether-etherketone), poly(phenylene sulfide), poly(arylene sulfone), poly(ethersulfone), poly(amide-imide), poly(1,4-phenylene), polycarbonate, nylon, and silicone. Where a fiber-based mesh is present as or in the surface layer 820 or the surface layer 840 (or both), the fiber-based mesh may include at least one of glass fiber, aramid fiber, graphite fiber, carbon fiber, inorganic mineral fiber, metal fiber, metallized synthetic fiber, and metallized inorganic fiber. Where a thermosetting coating is present as or in the surface layer 820 or the surface layer 840 (or both), the coating may include at least one of unsaturated polyurethane, vinyl ester, phenolic resin, and epoxy resin. In the case where an inorganic coating exists as or is present in the surface layer 820 or the surface layer 840 (or both), the inorganic coating may include a mineral containing cations selected from Ca, Mg, Ba, Si, Zn, Ti and Al or may include at least one of gypsum, calcium carbonate and mortar. In the case where a nonwoven fabric exists as or is present in the surface layer 820 or the surface layer 840 (or both), the nonwoven fabric may include a thermoplastic material, a thermosetting adhesive, an inorganic fiber, a metal fiber, a metallized inorganic fiber and a metallized synthetic fiber. If desired, one of the surface layers 820, 40 may independently include an open-cell structure or a closed-cell structure. Although not shown, a decorative layer may be bonded to the surface layer 820 or the surface layer 840 (or both). As noted herein, the decorative layer may be formed, for example, by a thermoplastic film of polyvinyl chloride, a polyolefin, a thermoplastic polyester, a thermoplastic elastomer, etc. The decorative layer may also be a multilayer structure comprising a foam core formed by, for example, polypropylene, polyethylene, polyvinyl chloride, polyurethane, etc. Fabrics may be bonded to the foam core, such as woven fabrics made of natural and synthetic fibers, nonwoven fabrics of organic fibers after needle punching, etc., pile fabrics, knits, flocked fabrics, or other such materials.The fabric can also be bonded to the foam core with thermoplastic adhesives, including pressure sensitive adhesives and hot melt adhesives, such as polyamides, modified polyolefins, urethanes, and polyolefins. The decorative layer can also be prepared using spunbond, thermal bond, hydroentangled, meltblown, wet laid, and / or dry laid processes.

[0101] In certain embodiments, two or more prepregs or cores may be bonded to each other via one or more skin layers. Fig. 9 , an article 900 is shown, which includes a prepreg or core 910 bonded to a prepreg or core 930 by an intermediate layer 920, and a skin layer 940 disposed on the prepreg or core 910. If desired, the skin layer 940 may be disposed on the prepreg or core 930 alternatively or another skin layer (not shown) may be disposed on the prepreg or core 920. Each of the prepregs or cores 910, 930 may be the same or may be different. In some cases, the thermoplastic material and fiber of the prepregs or cores 910, 930 are the same, but the flame retardant material loading or the type of flame retardant material present in the prepregs or cores 910, 930 is different. In other cases, the type and / or amount of flame retardant material in the prepregs or cores 910, 930 may be the same and one or both of the thermoplastic material and / or fiber may be different, for example, may be chemically different or may be present in different amounts. In some cases, one or more suitable additional flame retardants may be present in one or both of the prepregs or cores 910, 930, such as halogenated or non-halogenated flame retardants, combinations of EG materials with Group II or Group III metal hydroxides, compounded flame retardant materials, etc. Although the thickness of the prepregs or cores 910, 930 is shown as Fig. 9910, 930, but the thickness of the prepreg or core 910, 930 may vary. For example, two thin core layers may be bonded to each other instead of using a single core layer of similar thickness. In some configurations, one or both of the prepreg or core 910, 930 may include a lofting agent, such as an expandable graphite material or microspheres or other materials. In some configurations, layer 920 and skin layer 940 may independently include, for example, a film (e.g., a thermoplastic film or an elastic film), an inorganic fiberglass, a mesh (e.g., a fiber-based mesh), a foil, a woven fabric, a nonwoven fabric, or exist as an inorganic coating, an organic coating, or a thermosetting coating disposed on the prepreg or core 830. In other cases, as measured according to ISO 4589 dated 1996, layer 920 and skin layer 940 may independently include a limiting oxygen index greater than about 22. Where a thermoplastic film is present as or in the surface layer 920 or the surface layer 940 (or both), the thermoplastic film may include at least one of poly(etherimide), poly(etherketone), poly(ether-etherketone), poly(phenylene sulfide), poly(arylene sulfone), poly(ethersulfone), poly(amide-imide), poly(1,4-phenylene), polycarbonate, nylon, and silicone. Where a fiber-based mesh is present as or in the surface layer 920 or the surface layer 940 (or both), the fiber-based mesh may include at least one of glass fiber, aramid fiber, graphite fiber, carbon fiber, inorganic mineral fiber, metal fiber, metalized synthetic fiber, and metalized inorganic fiber. Where a thermosetting coating is present as or in the surface layer 920 or the surface layer 940 (or both), the coating may include at least one of unsaturated polyurethane, vinyl ester, phenolic resin, and epoxy resin. In the case where the inorganic coating exists as the surface layer 920 or the surface layer 940 (or both) or exists therein, the inorganic coating may include a mineral containing cations selected from Ca, Mg, Ba, Si, Zn, Ti and Al or may include at least one of gypsum, calcium carbonate and mortar. In the case where the nonwoven fabric exists as the surface layer 920 or the surface layer 940 (or both) or exists therein, the nonwoven fabric may include a thermoplastic material, a thermosetting adhesive, an inorganic fiber, a metal fiber, a metallized inorganic fiber and a metallized synthetic fiber. In some cases, the surface layer 920 or the layer 940 may each independently include an open-cell structure or a closed-cell structure. Although not shown, the decorative layer may be bonded to the surface layer 940 or the prepreg or the core 930 (or both). As noted herein, the decorative layer may be formed, for example, by a thermoplastic film of polyvinyl chloride, a polyolefin, a thermoplastic polyester, a thermoplastic elastomer, etc. The decorative layer may also be a multilayer structure comprising a foam core formed by, for example, polypropylene, polyethylene, polyvinyl chloride, polyurethane, etc. Fabrics may be bonded to the foam core, such as woven fabrics made of natural and synthetic fibers, nonwoven fabrics of organic fibers after needle punching, etc., pile fabrics, knits, flocked fabrics, or other such materials.The fabric can also be bonded to the foam core with thermoplastic adhesives, including pressure sensitive adhesives and hot melt adhesives, such as polyamides, modified polyolefins, urethanes, and polyolefins. The decorative layer can also be prepared using spunbond, thermal bond, hydroentangled, meltblown, wet laid, and / or dry laid processes.

[0102] In certain embodiments, the strips of material may be placed on a prepreg or core layer. Fig.10 , shows an article 1000 comprising a prepreg or core 1010 having strips 1020, 1030 disposed in different areas of the prepreg or core 1010. If desired, such strips may be present Figures 1 to 9 . Strips 1020, 1030 may be the same or may be different. In some cases, as noted herein, strips 1020, 1030 may include a combination of a compounded flame retardant material, an EG material, an EG material and a Group II or Group III metal hydroxide, etc. For example, the strip may include a compounded flame retardant material containing a thermoplastic material, which may be melted to bond the strip to a prepreg or core 1010. In other cases, the strip may include a combination of an EG material and an MDH or ATH (or both). In some cases, strips 1020, 1030 may independently take the form of a prepreg or core as described herein. In other configurations, the strip may take the form of a skin or layer as described herein. In some cases, the strip may be placed in areas of, for example, article 1000 where different thicknesses are required. In other configurations, the strip comprising a compounded flame retardant material may be placed in areas where increased or enhanced flame retardancy is required.

[0103] In some embodiments, prepreg and core may include additional materials or additives to impart desired physical or chemical properties. The basic feature of using the flame retardant material described herein is that non-colored or colored articles can be produced. In the case of producing non-colored articles, the articles can then be colored or dyed to provide desired colors, textures, patterns, etc. For example, one or more dyes, thickeners, colorants, viscosity modifiers, smoke suppressants, synergistic materials, lofting agents, particles, powders, pesticides, foams or other materials can be mixed with prepreg or core or added to prepreg or core to impart desired colors, textures or properties. In some cases, prepreg or core can include one or more smoke suppressant compositions in an amount of about 0.2 wt % to about 10 wt %. Illustrative smoke suppressant compositions include but are not limited to stannate, zinc borate, zinc molybdate, magnesium silicate, calcium zinc molybdate, calcium silicate, calcium hydroxide and mixtures thereof. If desired, synergist materials may be present to enhance the physical properties of prepreg or core. For example, synergist enhancing flame retardancy may be present.

[0104] In other cases, the prepregs or cores described herein may contain thermosetting materials in a desired amount (e.g., in a minute amount less than about 50% by weight of the total weight of the prepreg or core) to impart desired properties to the core. Thermosetting materials may be mixed with thermoplastic materials or may be added as a coating to one or more surfaces of the prepreg or core.

[0105] In certain embodiments, the prepregs or cores described herein may be configured as (or used in) a glass mat thermoplastic composite (GMT) or a lightweight reinforced thermoplastic composite (LWRT). One such LWRT is manufactured by HANWHAAZDEL, Inc. and marketed under the trademark Materials for sale. Loaded with flame retardant materials Felt can provide desired features, including, for example, flame retardancy and enhanced processing capabilities. The surface density of such GMT or LWRT can be within the range of about 300 grams (gsm) to about 4000gsm per square meter of GMT or LWRT, but the surface density can be less than 400gsm or greater than 4000gsm according to specific application requirements. In some embodiments, the upper limit density can be less than about 4000gsm. In some cases, GMT or LWRT may include flame retardant materials placed in or present in the void space of porous GMT or LWRT and / or on the fibers of GMT or LWRT, such as a combination of EG materials and Group II or Group III metal hydroxides, mixed flame retardant materials, etc. In the case of GMT or LWRT prepregs or cores used in combination with flame retardant materials, the basic weight of GMT or LWRT can be reduced to, for example, less than 800gsm, 600gsm or 400gsm, while still providing suitable flame retardant properties. In some examples, the total thickness of the GMT or LWRT may be about 25 mm or less after lofting, 20 mm or less after lofting, greater than 3 mm before lofting, or greater than 6 mm before lofting. In some cases, the thickness before lofting may be between about 3 mm and about 7 mm, and the thickness after lofting may be between about 10 mm and about 25 mm.

[0106] In preparing the prepregs and cores described herein, it may be desirable to use a wet lay process. Fig.11A block diagram showing the method steps is presented in . For example, a liquid or fluid medium 1140 comprising dispersed materials, such as thermoplastic material 1120, fibers 1110, and flame retardant material 1130, such as a combination of EG material and Group II or Group III metal hydroxides, compounded flame retardant materials, etc., may be agitated or stirred in the presence of a gas (e.g., air or other gas); optionally with the addition of any one or more additives described herein (e.g., other flame retardants). The dispersion may then be laid onto a support (e.g., a wire screen or other support material) to provide a substantially uniform distribution of the one or more flame retardant materials in the laid material 1150. In order to increase the dispersion and / or uniformity of the flame retardant material, the agitated dispersion may include one or more active agents, such as anionic, cationic, or non-ionic active agents, such as those sold by IndustrialSoaps Ltd. under the name ACE liquids, as The active agents sold as FN 15 materials by GloverChemicals Ltd. and those sold as AMINE Fb 19 materials by Float-Ore Ltd. These agents can aid in the dispersion of air in a liquid dispersion. The components can be added to a mixing tank, flotation cell or other suitable device in the presence of air to provide a dispersion. While aqueous dispersions are ideally used, one or more non-aqueous fluids may also be present to aid in the dispersion; to change the viscosity of the fluid; or to otherwise impart desired physical or chemical properties to the dispersion or prepreg, core or article.

[0107] In some cases, after the dispersion has been mixed for a sufficient time, the fluid containing the suspended material can be placed on a mesh screen, moving wire or other suitable support structure to provide a web of the laid material 1150. Suction or reduced pressure can be provided to the web to remove any liquid from the laid material, leaving behind the thermoplastic material, the one or more flame retardant materials, and any other materials present, such as fibers, additives, etc. The resulting web 1160 can be dried and optionally consolidated or pressed to a desired thickness and then fully formed to provide the desired prepreg or core 1170. Although wet-laid processes can be used, depending on the properties of the thermoplastic material, flame retardant material, and other materials present, it may be necessary to use air-laid processes, dry blending processes, carding and needle punching processes, or other known methods for preparing nonwoven products instead. In some cases, additional flame retardant material may be sprayed onto the surface of the prepreg or core after the prepreg or core has hardened to a certain extent by passing the sheet under a plurality of coating jets configured to spray the flame retardant material onto the prepreg or core surface at an angle of about ninety degrees. In addition, one or more skin layers 1165 may be added to core 1170 to provide article 1180.

[0108] In some configurations, the prepreg and core described herein can be prepared by combining thermoplastic materials, fibers, one or more flame retardant materials (e.g., a combination of EG materials and Group II or Group III metal hydroxides, a compounded flame retardant material, etc.) in the presence of a surfactant in an aqueous solution or foam. The combined components can be mixed or stirred for a sufficient time to disperse the various materials and provide a substantially homogeneous aqueous mixture of the material. The dispersed mixture is then laid on any suitable support structure (e.g., a wire mesh or other screens or supports with a desired porosity). The water can then be evacuated through the wire mesh to form a mesh. The mesh is dried and heated at a temperature exceeding the softening temperature of the thermoplastic powder. The mesh is then cooled and pressed to a predetermined thickness to prepare a composite sheet with a void content between about 1% and about 95%. In an alternative embodiment, the aqueous foam also includes a bonding material.

[0109] In other methods of preparing the article, the flame retardant material may be coated or sprayed onto the prepreg after the web is formed. In the case of using a mixed flame retardant material comprising a flame retardant material compounded with a thermoplastic material, spraying or coating the mixed flame retardant material onto the heated prepreg may cause the thermoplastic material of the mixed flame retardant material to melt and load the prepreg with the flame retardant material. In the case of using a combination of an EG material and a Group II or Group III metal hydroxide, spraying or coating the mixture onto the heated prepreg may cause a surface layer of the mixture to be formed and / or cause the mixture to be absorbed into the void spaces of the prepreg. Reference Fig.12 , shows a method in which a liquid or fluid medium 1240 containing dispersed material, such as thermoplastic material 1120 and fibers 1110, optionally with any one or more additives described herein, may be agitated or stirred in the presence of a gas (e.g., air or other gas). The dispersion 1240 may then be laid onto a support (e.g., a wire screen or other support material) to provide a laid material 1250. To increase uniformity, the agitated dispersion may contain one or more active agents, such as anionic, cationic, or nonionic active agents, such as those sold under the name ACE liquids by Industrial Soaps Ltd., as Active agents sold by Glover Chemicals Ltd. as FN15 material and those sold by Float-Ore Ltd. as AMINE Fb 19 material. These agents can assist in the dispersion of air in a liquid dispersion. The components can be added to a mixing tank, flotation cell, or other suitable device in the presence of air to provide a dispersion. Although aqueous dispersions are ideally used, one or more non-aqueous fluids may also be present to assist in dispersion; to change the viscosity of the fluid; or to otherwise impart desired physical or chemical properties to the dispersion or prepreg, core, or article. In some cases, after the dispersion has been mixed for a sufficient amount of time, the fluid containing the suspended material may be placed on a mesh screen, moving wire, or other suitable support structure to provide a mesh of the laid material 1250. After the material is laid, the flame retardant material 1230 may be added by spraying or coating the material onto the laid material 1250 to provide a combined laid material. When the material 1250 of the laying is heated and the mixed flame retardant material of the spraying, the thermoplastic material and the thermoplastic material 1220 of the mixed flame retardant material can be melted and the flame retardant material of the mixed flame retardant material can be loaded into the material of the laying. In the case of using a combination of EG material and Group II or Group III metal hydroxides, the melting of the thermoplastic material 1220 allows the material to occupy the inner part of the laying material and / or remain on the surface of the laying material. Alternatively, the flame retardant material can be added after the web 1260 is formed. Suction or decompression can be provided to the web 1260 to remove any liquid from the laid material, thereby leaving the thermoplastic material, the flame retardant material and any other material present, such as fiber, additive, etc. The resulting web 1260 can be dried and optionally consolidated or pressed to a desired thickness, and then fully formed to provide a desired prepreg or core 1270. Although wet web forming can be used, according to the properties of thermoplastic materials, one or more flame retardant materials and other materials present, it may be necessary to use air-laid method, dry blending method, carding and needle punching method or other known methods for preparing nonwoven products instead. In some cases, after the prepreg or core has hardened to a certain extent, the plate can be sprayed with additional flame retardant material on the surface of the prepreg or core by passing under multiple coating jets, and the multiple coating jets are configured to spray the mixed flame retardant material to the prepreg or core surface at about ninety degree angles. In addition, one or more skin layers 1265 can be added to the core 1270 to provide article 1280.

[0110] In some instances, a prepreg or core in the form of a porous GMT can be prepared. In some cases, the following materials can be used to prepare the GMT: chopped glass fibers, thermoplastic materials, mixed flame retardant materials, and optional thermoplastic polymer films and / or woven or nonwoven fabrics prepared with glass fibers or thermoplastic resin fibers such as polypropylene (PP), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polycarbonate (PC), PC / PBT blends, or PC / PET blends. In some embodiments, PP, PBT, PET, PC / PET blends, or PC / PBT blends can be used as thermoplastic materials. In order to prepare glass mats, thermoplastic materials, reinforcing materials, one or more flame retardant materials, and / or other additives can be added or metered into the dispersed foam contained in the top opening mixing tank equipped with an impeller. Without wishing to be limited by any particular theory, the presence of trapped air pockets in the foam can help disperse the glass fibers, thermoplastic materials, and flame retardant materials. In some examples, the dispersed mixture of glass and resin can be pumped to the headbox (head-box) positioned above the wire section of the paper machine via a distribution manifold. Then, when the dispersed mixture is provided to the moving wire screen using vacuum, foam (rather than glass fiber, flame retardant material or thermoplastic material) can be removed to continuously produce a uniform fiber wet web. The wet web can be passed through a dryer at a suitable temperature to reduce the moisture content and melt or soften the thermoplastic material. When the hot web leaves the dryer, surface layers such as films can be laminated to the web by passing the web of glass fiber, flame retardant material, thermoplastic material and film through the roller gap of a group of heated rollers. If necessary, additional layers such as nonwoven and / or woven fabric layers can also be attached to one or both sides of the web together with the film to facilitate the ease of handling glass fiber reinforced felt. Then, the composite can be passed through a stretching roller and continuously cut (cut) into a desired size so as to be subsequently formed into a final product article. Additional information regarding the preparation of such GMT composites, including materials and processing conditions suitable for forming such composites, is 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. US2005 / 0082881, US2005 / 0228108, US2005 / 0217932, US2005 / 0215698, US 2005 / 0164023, and US2005 / 0161865.

[0111] In some cases, a method for preparing a composite article includes combining thermoplastic material, reinforcing fiber and compounded flame retardant material into a mixture to form an aqueous foam for stirring. The foam is placed on a linear support, and water is evacuated to form a mesh or open-cell structure comprising thermoplastic material, fiber and compounded flame retardant material. In some cases, the mesh is then heated to a first temperature higher than the melting temperature of the thermoplastic material. In the case where the compounded flame retardant material comprises a thermoplastic material compounded with a flame retardant material, the melting temperature can be selected so that both thermoplastic materials are melted. If necessary, the core can be pressed before being fully formed so that the compounded flame retardant sheet is positioned closer to each other in the core layer. In some cases, a roller or other device can then be used, for example, to apply pressure to the mesh, to provide a thermoplastic composite sheet comprising a flame retardant material from a compounded flame retardant material dispersed in the mesh.

[0112] In some cases, a method for preparing a composite article includes combining a mixture of thermoplastic material, reinforcing fiber and EG material with Group II or Group III metal hydroxide (such as MDH or ATH) into a mixture to form a stirred aqueous foam. The foam is placed on a linear support, and water is evacuated to form a mesh or open-cell structure comprising thermoplastic material, fiber and EG material / Group II or Group III metal hydroxide material. In some cases, the mesh is then heated to a first temperature higher than the melting temperature of the thermoplastic material. If necessary, the core can be pressed before being fully formed so that the EG material / Group II or Group III metal hydroxide material is positioned closer to each other in the core layer. In some cases, a roller or other device can then be used to apply pressure to the mesh, so as to provide a thermoplastic composite sheet comprising a flame retardant material from the EG material / Group II or Group III metal hydroxide material dispersed in the mesh.

[0113] In some embodiments, a composite article comprising a thermoplastic fiber reinforced porous core layer and a surface layer disposed on at least one surface of the porous core layer can be used in environments such as office appliances, seats, etc., wherein the porous core layer comprises a mesh formed by a plurality of reinforcing fibers, a mixed flame retardant material, and a thermoplastic material, and the composite article comprises an effective amount of a mixed flame retardant material to meet the Class A requirements as tested by ASTM E84 dated 2009. In some cases, the thermoplastic material comprises a polyolefin, the reinforcing fiber comprises a glass fiber, and the mixed flame retardant material comprises a Group II metal hydroxide mixed with a polyolefin. In other examples, the glass fiber is present in about 30% to 60% by weight, the mixed flame retardant material is present in about 30% to about 50% by weight, and the remainder of the core layer comprises a thermoplastic material. If desired, the surface layer may be one or more of a mesh, an open-cell film, or a closed-cell film. In some cases, an adhesive layer may be present between the core layer and the surface layer. In certain embodiments, the article may include a second surface layer disposed on the opposite surface of the core layer. In some configurations, the core layer does not contain any added flame retardant, for example, a compounded flame retardant acts as a flame retardant, but no additional flame retardant, such as a halogenated flame retardant, is present. In some instances, the article may include a first adhesive layer between the core layer and the skin layer and a second adhesive layer between the core layer and the second skin layer. In other instances, the article may include a decorative layer disposed on the skin layer. For example, in office applications, it may be desirable to staple, glue, or otherwise attach a fabric or covering to the article to provide an aesthetically more pleasing article.

[0114] In some instances, the non-molded composite article includes a thermoplastic fiber reinforced porous core layer and a surface layer disposed on at least one surface of the porous core layer, the porous core layer comprising a pressed mesh formed by a mixed flame retardant material and a plurality of reinforcing fibers bonded together by a thermoplastic material, the composite article comprising an effective amount of a mixed flame retardant material to meet the Class A requirements as tested by ASTM E84 dated 2009 without molding the composite article. In some cases, the core layer does not include any added flame retardant material, such as a mixed flame retardant acting as a flame retardant, but no other flame retardant, such as a halogenated flame retardant, is present in the core layer. In other instances, the article may include a lofting agent, such as microspheres. In some instances, the surface layer is configured as an open-cell mesh or a closed-cell mesh. In some instances, the article may include another surface layer disposed on the opposite surface of the core layer. In other embodiments, another surface layer is configured as a closed-cell mesh or an open-cell mesh.

[0115] In certain embodiments, a method of preparing a thermoplastic composite article including a porous core layer comprising a plurality of reinforcing fibers, a thermoplastic material, and a compounded flame retardant material is performed by heating the reinforcing fibers, the thermoplastic material, and the compounded flame retardant material to a first temperature above the melting point of the thermoplastic material (or in the case where the compounded flame retardant material comprises a thermoplastic material compounded with the flame retardant material, above the melting point of the thermoplastic material of the compounded flame retardant material) to form a mesh comprising the thermoplastic material, the compounded flame retardant material, and the reinforcing fibers, the thermoplastic composite article comprising an effective amount of the compounded flame retardant material to meet Class A requirements as tested by ASTM E84 dated 2009. In certain embodiments, the method includes using the thermoplastic composite article as a building board without molding the thermoplastic composite article. In some cases, the method includes pressing the core layer of the thermoplastic article before forming the core layer. In some examples, the method includes configuring the thermoplastic composite article to have a mesh on one surface of the thermoplastic composite article. In other embodiments, the method includes configuring the thermoplastic composite article to have another scrim on an opposing surface of the thermoplastic composite article, wherein at least one of the scrim and the other scrim comprises an open cell structure. In other examples, the method includes configuring the porous core layer to have about 35 wt% to 55 wt% glass fiber as reinforcing fiber and at least 30 wt% compounded flame retardant material, and the remainder of the porous core layer comprises a thermoplastic material.

[0116] In certain examples, a method includes combining a first thermoplastic material, reinforcing fibers, and a compounded flame retardant material comprising a Group II metal hydroxide compounded with a second thermoplastic material into a mixture to form an agitated aqueous foam, placing the agitated aqueous foam on a wire support, evacuating water to form a mesh, heating the mesh to a first temperature equal to or greater than the melting temperature of the first thermoplastic material and the second thermoplastic material, and pressing the mesh to a selected thickness, wherein the thermoplastic composite article contains an effective amount of the compounded flame retardant material to meet Class A requirements as tested by ASTM E84 dated 2009. In some examples, the pressing step includes passing the heated mesh through a set of rollers. In some examples, the method may include mixing the agitated aqueous foam until the compounded flame retardant material is uniformly dispersed in the agitated aqueous foam. In other cases, the method may include applying a mesh to at least one surface of the thermoplastic composite article before pressing the article. In some cases, the method may include applying a mesh to at least one surface of the thermoplastic composite article after pressing the article. In some cases, the method can include bonding the thermoplastic article to a second thermoplastic article comprising substantially the same composition as the thermoplastic article and a different thickness.

[0117] Certain embodiments are described below to better illustrate some of the novel aspects and configurations described herein.

[0118] Example 1

[0119] The dispersion was prepared using initial polypropylene (PP), glass fiber, and magnesium hydroxide (MDH) compounded with polypropylene (MDH:PP ratio of 7:3). The dispersion included adding approximately 40% by weight of MDH:PP to a mixture comprising 60% by weight of glass fiber and 40% by weight of PP. The mixture was agitated using a mixing trough and laid onto a wire screen. Suction was applied to remove the liquid, leaving the three components. The mesh was heated to melt the PP material. After heating, the mesh was allowed to cool and a white plate was formed. The plates were tested according to the protocol specified in ASTM E84, dated 2009. According to the ASTM E84 test, the plates met the Class A standard.

[0120] Example 2

[0121] Dispersion is prepared using initial polypropylene (PP), glass fiber, magnesium hydroxide (MDH) and expandable graphite material (Asbury 3335EG). Depending on the exact amount of flame retardant material present, the dispersion includes about 3% by weight of EG, a variable amount of MDH (see Table 1 below), about 38% by weight to 44% by weight of glass fiber, and the balance weight percentage (45% by weight -55% by weight) is PP. Each mixture is stirred using a mixing tank and laid onto a wire screen. Suction is applied to remove liquid, leaving four components. The mesh is heated to melt the PP. After heating, the mesh is allowed to cool and form a plate. Each plate with different amounts of MDH is molded to a thickness of about 6 mm. The total basis weight of the plate is about 1200 gsm.

[0122] Table 1 below shows the results of the SAE Self-Extinguishing (SE) Flammability Test (as measured using SAE J369 November 2007 revision).

[0123] Table 1

[0124] sample EG% MDH% Non-oil immersed SAE SE Oil immersed SAE SE 1 3 0 no yes 2 3 1.5 no yes 3 3 3 no yes 4 3 6 no yes 5 3 9 yes yes 6 3 12 yes yes

[0125] The results are consistent with the presence of MDH allowing EG levels to be reduced while both non-oil immersed and oil immersed samples still pass the SAE J369 test. For example, approximately 9 wt % MDH was used in combination with 3 wt % EG allowing the panels to meet the SAEF369 flammability test. In contrast, for non-oil immersed samples, passing the SAE J369 test requires EG levels significantly higher than 3 wt %, such as 10 wt % or more, which increases the overall cost and manufacturing complexity when higher levels of EG material are used.

[0126] When introducing elements of the embodiments disclosed herein, the articles "a / an", "the", and "said" are intended to mean that there is 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. Those of ordinary skill in the art will recognize that, in view of the benefit of this disclosure, various components of the embodiments may be interchanged or substituted with various components in other embodiments.

[0127] While certain aspects, embodiments, and implementations have been described above, those skilled in the art will appreciate that, given the benefit of this disclosure, additions, substitutions, modifications, and variations of the illustrative aspects, embodiments, and implementations disclosed are possible.

Claims

1. A method, comprising: combining a first thermoplastic material, reinforcing fibers, and a compounded flame retardant material comprising a flame retardant material and a second thermoplastic material to form an agitated aqueous foam; placing the stirred aqueous foam onto a wire support; The water is evacuated to form a mesh; heating the web to a first temperature equal to or greater than the melting temperature of the first thermoplastic material; as well as Pressure is applied to the web to provide a thermoplastic composite sheet.

2. The method of claim 1, wherein the combining step comprises mixing the first thermoplastic material, the reinforcing fibers, and the compounded flame retardant material until a homogenous, stirred aqueous foam is formed.

3. The method of claim 1, further comprising heating the web to a second temperature greater than the first temperature and equal to or higher than a melting temperature of a second thermoplastic material compounded with the flame retardant material.

4. The method of claim 1 further comprising heating the web using convection heating.

5. The method of claim 4, further comprising applying pressure to the heated thermoplastic composite sheet.

6. The method of claim 1 further comprising heating the thermoplastic composite sheet using radiant heating.

7. The method of claim 1, further comprising disposing an additional compounded flame retardant material on a surface of the thermoplastic composite sheet.

8. The method of claim 1, further comprising configuring the compounded flame retardant material to include a divalent metal hydroxide.

9. The method of claim 1 further comprising bonding the thermoplastic composite sheet to a skin layer.

10. The method of claim 1, further comprising configuring an amount of flame retardant material from the compounded flame retardant material such that the composite sheet is Class A as tested by ASTM E84.

11. A method comprising: combining a first thermoplastic material and reinforcing fibers to form an agitated aqueous foam; placing the stirred aqueous foam onto a wire support; The water is evacuated to form a mesh; heating the web to a first temperature equal to or greater than the melting temperature of the first thermoplastic material; adding a compounded flame retardant material to the heated web to provide a composite web, the compounded flame retardant material comprising a flame retardant material and a second thermoplastic material; and Pressure is applied to the composite web to provide a thermoplastic composite sheet.

12. The method of claim 11, further comprising configuring the compounded flame retardant material to include a Group II metal hydroxide.

13. The method of claim 12, further comprising configuring the second thermoplastic material to be the same as the first thermoplastic material so that the second thermoplastic material melts when the compounded flame retardant is added to the heated web.

14. The method of claim 11, further comprising heating the composite web to a second temperature greater than the first temperature and equal to or greater than a melting temperature of a second thermoplastic material compounded with the flame retardant material.

15. The method of claim 11, further comprising heating the web using convection heating.

16. The method of claim 11, further comprising heating the thermoplastic composite sheet using radiant heating.

17. The method of claim 11, further comprising disposing an additional compounded flame retardant material on a surface of the thermoplastic composite sheet.

18. The method of claim 11 further comprising adding a lofting agent to the agitated aqueous foam.

19. The method of claim 11, further comprising bonding the thermoplastic composite sheet to a skin layer.

20. The method of claim 11, further comprising configuring an amount of flame retardant material from the compounded flame retardant material such that the composite sheet is Class A as tested by ASTM E84.

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