Method for improving bulking agent retention using bicomponent fibers

Abstract

Methods of forming lightweight reinforced thermoplastic core layers and articles including the core layers are described. In some examples, the methods use a combination of thermoplastic materials, reinforcing fibers, and bicomponent fibers to increase the retention of leavening agents in the core layer. The methods permit the use of less material while still providing sufficient leavening capacity of the resulting core layer.

Description

[0001] Priority application

[0002] This application is related to and claims priority to and the benefit of U.S. Provisional Application No. 62 / 800,307, filed on February 1, 2019, the entire disclosure of which is hereby incorporated by reference herein. Technical Field

[0003] Certain embodiments relate to methods for improving the retention of bulking agents in thermoplastic composite articles. More specifically, some examples describe methods for producing thermoplastic composite articles having improved retention of bulking agents within the thermoplastic composite article. Background Art

[0004] Certain automotive and architectural applications often use thermoplastic-type materials in place of traditional steel or metal products. Using thermoplastic-type materials creates unique considerations that steel or metal products do not. Summary of the invention

[0005] Certain aspects are described herein illustrating some methods of configuring and producing lightweight reinforced thermoplastic composite articles.

[0006] In one aspect, the method for producing a porous composite article comprises combining an inorganic reinforcing fiber, an organic reinforcing fiber and a thermoplastic material in a liquid to produce an aqueous foam, wherein the organic reinforcing fiber comprises a core-shell arrangement, wherein the melting point of the shell material in the shell of the core-shell arrangement is substantially similar to the melting point of the thermoplastic material, and wherein the melting point of the core material in the core of the core-shell arrangement is at least 20 degrees Celsius higher than the melting point of the thermoplastic material. The method may also include depositing the aqueous foam onto a moving mesh screen. The method may also include removing liquid from the aqueous foam deposited on the moving mesh screen to form a net of an open cell structure formed by the thermoplastic material, the inorganic reinforcing fiber and the organic reinforcing fiber. The method may also include depositing a leavening agent onto the formed net. The method may also include pressing the formed net containing the deposited leavening agent to provide a porous composite article.

[0007] In some instances, the method comprises using a negative pressure provided at the bottom surface of the formed web to draw the leavening agent into the voids of the formed web during the deposition of the leavening agent. In other instances, at least 50% of the deposited leavening agent is retained by the formed web. In some embodiments, the organic reinforcing fiber comprises: a shell comprising a polyolefin and a core comprising a polyester. In other embodiments, the polyolefin comprises polyethylene. In some instances, the polyethylene is a linear low density polyethylene. For example, the density of the linear low density polyethylene is from about 0.91 g / cm3 to about 0.94 g / cm3. In some instances, the polyester comprises one or more of polyethylene terephthalate, polybutylene terephthalate, and polynaphthyl terephthalate.

[0008] In other examples, the organic reinforcing fiber comprises: a shell comprising a polyolefin and a core comprising a polyamide. In certain examples, the polyolefin comprises polyethylene. In some examples, the polyethylene is a linear low-density polyethylene. For example, the density of the linear low-density polyethylene is about 0.91 g / cm3 to about 0.94 g / cm3. In some examples, the polyamide comprises a copolyamide. In some examples, the polyamide comprises nylon.

[0009] In some embodiments, the thermoplastic material comprises polyolefin, the inorganic reinforcing fibers comprise glass fibers, the organic reinforcing fibers comprise polyolefin in the shell and polyester in the core, and wherein the bulking agent comprises expandable microspheres. In some instances, the thermoplastic material is polypropylene, the polyolefin of the shell comprises polyethylene, and the polyester of the core comprises polyethylene terephthalate.

[0010] In other embodiments, the thermoplastic material comprises polyolefin, the inorganic reinforcing fibers comprise glass fibers, the organic reinforcing fibers comprise polyolefin in the shell and polyamide in the core, and wherein the bulking agent comprises expandable microspheres. In some instances, the thermoplastic material is polypropylene, the polyolefin of the shell comprises polyethylene, and the polyamide of the core comprises nylon.

[0011] In some examples, the thermoplastic material comprises polypropylene, the inorganic reinforcing fibers comprise glass fibers, the organic reinforcing fibers comprise polyethylene in the shell and polyester in the core, wherein the melting point of the polyester in the core is at least fifty degrees Celsius higher than the melting point of the polyethylene in the shell, wherein the bulking agent comprises expandable microspheres, and wherein the porosity of the porous thermoplastic composite article is 20% to 80%,

[0012] In certain instances, the thermoplastic material comprises polypropylene, the inorganic reinforcing fibers comprise glass fibers, the organic reinforcing fibers comprise polyethylene in the shell and polyamide in the core, wherein the melting point of the polyamide in the core is at least fifty degrees Celsius higher than the melting point of the polyethylene in the shell, wherein the bulking agent comprises expandable microspheres, and wherein the porosity of the porous thermoplastic composite article is from 20% to 80%.

[0013] In another aspect, the method for producing a porous composite article comprises combining an inorganic reinforcing fiber, an organic reinforcing fiber and a thermoplastic material in a liquid to produce an aqueous foam, wherein the organic reinforcing fiber comprises a side-by-side arrangement, wherein the melting point of the first fiber in the side-by-side arrangement is substantially similar to the melting point of the thermoplastic material, and wherein the melting point of the second fiber arranged side by side is at least 20 degrees Celsius higher than the melting point of the thermoplastic material. The method may also include depositing the aqueous foam onto a moving mesh screen. The method may also include removing liquid from the deposited aqueous foam on the moving mesh screen to form a net of an open-cell structure formed by the thermoplastic material, the inorganic reinforcing fiber and the organic reinforcing fiber. The method may also include depositing a leavening agent onto the formed net. The method may also include pressing the formed net comprising the deposited leavening agent to provide a porous composite article.

[0014] In certain embodiments, negative pressure may be provided at the bottom surface of the formed web during the deposition of the leavening agent to draw the leavening agent into the voids of the formed web. In some instances, at least 50% of the deposited leavening agent is retained by the formed web. In some instances, the first fiber of the organic reinforcing fiber comprises a polyolefin, and the second fiber of the organic reinforcing fiber comprises a polyester. In other instances, the polyolefin comprises polyethylene. In some instances, the polyethylene is a linear low-density polyethylene. For example, the density of the linear low-density polyethylene is from about 0.91 g / cm3 to about 0.94 g / cm3. In some instances, the polyester comprises one or more of polyethylene terephthalate, polybutylene terephthalate, and polynaphthyl terephthalate.

[0015] In some instances, the first fiber of the organic reinforcing fiber comprises a polyolefin, and the second fiber of the organic reinforcing fiber comprises a polyamide. In some cases, the polyolefin comprises polyethylene. In other instances, the polyethylene is a linear low-density polyethylene. In some instances, the density of the linear low-density polyethylene is from about 0.91 g / cm3 to about 0.94 g / cm3. In some embodiments, the polyamide comprises a copolyamide. In some instances, the polyamide comprises nylon.

[0016] In other examples, the thermoplastic material comprises polyolefin, the inorganic reinforcing fibers comprise glass fibers, the organic reinforcing fibers comprise: a first fiber comprising polyolefin and a second fiber comprising polyester, and wherein the bulking agent comprises expandable microspheres. In some examples, the thermoplastic material is polypropylene, the polyolefin of the first fiber comprises polyethylene, and the polyester of the second fiber comprises polyethylene terephthalate.

[0017] In certain embodiments, the thermoplastic material comprises polyolefin, the inorganic reinforcing fibers comprise glass fibers, the organic reinforcing fibers comprise: a first fiber comprising polyolefin and a second fiber comprising polyamide, and wherein the bulking agent comprises expandable microspheres. In some instances, the thermoplastic material is polypropylene, the polyolefin of the first fiber comprises polyethylene, and the polyamide of the second fiber comprises nylon.

[0018] In certain embodiments, the thermoplastic material comprises polypropylene, the inorganic reinforcing fibers comprise glass fibers, the organic reinforcing fibers comprise: first fibers comprising polyethylene and second fibers comprising polyester, wherein the melting point of the polyester in the second fibers is at least fifty degrees Celsius higher than the melting point of the polyethylene in the first fibers, wherein the bulking agent comprises expandable microspheres, and wherein the porous thermoplastic composite article has a porosity of 20% to 80%,

[0019] In other embodiments, the thermoplastic material comprises polypropylene, the inorganic reinforcing fibers comprise glass fibers, the organic reinforcing fibers comprise: first fibers comprising polyethylene and second fibers comprising polyamide, wherein the melting point of the polyamide in the second fibers is at least fifty degrees Celsius higher than the melting point of the polyethylene in the first fibers, wherein the bulking agent comprises expandable microspheres, and wherein the porosity of the porous thermoplastic composite article is 20% to 80%.

[0020] In another aspect, the method for producing a porous composite article comprises combining reinforcing fibers, bicomponent fibers and thermoplastic materials in a liquid to produce an aqueous foam, wherein the bicomponent fibers comprise a core-shell arrangement, wherein the melting point of the shell material in the shell of the core-shell arrangement is substantially similar to the melting point of the thermoplastic material, and wherein the melting point of the core material in the core of the core-shell arrangement is at least twenty degrees Celsius higher than the melting point of the thermoplastic material. In some instances, the method comprises depositing the aqueous foam onto a moving mesh screen. In other instances, the method comprises removing liquid from the deposited aqueous foam on the moving mesh screen to form a net of an open cell structure formed by the thermoplastic material, reinforcing fibers and bicomponent fibers. The method may also include depositing a leavening agent onto the formed net. The method may also include pressing the formed net comprising the deposited leavening agent to provide a porous composite article.

[0021] In additional aspects, the method for producing a porous composite article comprises combining reinforcing fibers, bicomponent fibers, and thermoplastic materials in a liquid to produce an aqueous foam, wherein the bicomponent fibers comprise a side-by-side arrangement, wherein the melting point of the first fibers in the side-by-side arrangement is substantially similar to the melting point of the thermoplastic material, and the melting point of the second fibers in the side-by-side arrangement is at least twenty degrees Celsius higher than the melting point of the thermoplastic material. In some examples, the method comprises depositing the aqueous foam onto a moving mesh screen. The method may also comprise removing liquid from the deposited aqueous foam on the moving mesh screen to form a mesh of an open-cell structure formed by the thermoplastic material, the reinforcing fibers, and the bicomponent fibers. The method may comprise depositing a leavening agent onto the formed mesh. The method may also comprise pressing the formed mesh comprising the deposited leavening agent to provide a porous composite article.

[0022] In another aspect, the method for producing a porous composite article comprises combining inorganic reinforcing fibers, organic reinforcing fibers, thermoplastic materials and leavening agents in a liquid to produce an aqueous foam, wherein the organic reinforcing fibers comprise a core-shell arrangement, wherein the melting point of the shell material in the shell of the core-shell arrangement is substantially similar to the melting point of the thermoplastic material, and wherein the melting point of the core material in the core of the core-shell arrangement is at least twenty degrees Celsius higher than the melting point of the thermoplastic material. The method may also include depositing the aqueous foam onto a moving mesh screen. The method may also include removing liquid from the deposited aqueous foam on the moving mesh screen to form a net of an open-cell structure formed by thermoplastic materials, inorganic reinforcing fibers and organic reinforcing fibers, wherein the formed net comprises a leavening agent captured in the net. The method may also include pressing the formed net comprising the deposited leavening agent to provide a porous composite article.

[0023] In another aspect, the method for producing a porous composite article comprises combining inorganic reinforcing fibers, organic reinforcing fibers, thermoplastic materials and leavening agents in a liquid to produce an aqueous foam, wherein the organic reinforcing fibers are arranged side by side, wherein the melting point of the first fibers in the side by side arrangement is substantially similar to the melting point of the thermoplastic material, and wherein the melting point of the second fibers arranged side by side is at least twenty degrees Celsius higher than the melting point of the thermoplastic material. The method may also include depositing the aqueous foam onto a moving mesh screen. The method may also include removing liquid from the deposited aqueous foam on the moving mesh screen to form a net of an open-cell structure formed by thermoplastic materials, inorganic reinforcing fibers and organic reinforcing fibers, wherein the formed net includes a leavening agent captured in the net. The method may also include pressing the formed net including the deposited leavening agent to provide a porous composite article.

[0024] In additional aspects, a method for producing a porous composite article comprises combining reinforcing fibers, bicomponent fibers, a thermoplastic material, and a leavening agent in a liquid to produce an aqueous foam, wherein the bicomponent fibers comprise a core-shell arrangement, wherein the melting point of the shell material in the shell of the core-shell arrangement is substantially similar to the melting point of the thermoplastic material, and wherein the melting point of the core material in the core of the core-shell arrangement is at least twenty degrees Celsius higher than the melting point of the thermoplastic material. The method may also include depositing the aqueous foam onto a moving mesh screen. The method may also include removing liquid from the deposited aqueous foam on the moving mesh screen to form a mesh of an open cell structure formed by the thermoplastic material, the reinforcing fibers, and the bicomponent fibers, wherein the formed mesh comprises a leavening agent captured in the mesh, and pressing the formed mesh comprising the deposited leavening agent to provide a porous composite article.

[0025] In another aspect, the method for producing a porous composite article comprises combining reinforcing fibers, bicomponent fibers, thermoplastic materials and leavening agents in a liquid to produce an aqueous foam, wherein the bicomponent fibers comprise a side-by-side arrangement, wherein the melting point of the first fibers in the side-by-side arrangement is substantially similar to the melting point of the thermoplastic material, and wherein the melting point of the second fibers arranged side by side is at least twenty degrees Celsius higher than the melting point of the thermoplastic material. The method may also include depositing the aqueous foam onto a moving mesh screen. The method may also include removing liquid from the deposited aqueous foam on the moving mesh screen to form a net of an open cell structure formed by the thermoplastic material, reinforcing fibers and bicomponent fibers, wherein the formed net comprises a leavening agent captured in the net. The method may also include pressing the formed net comprising the deposited leavening agent to provide a porous composite article.

[0026] Additional aspects, examples, embodiments, and configurations are described in further detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Certain aspects, embodiments and examples are described with reference to the accompanying drawings, in which:

[0028] Figure 1 is a diagrammatic representation of a core-sheath fiber arrangement according to some examples;

[0029] Figure 2 is an illustration of a side-by-side fiber arrangement according to certain embodiments;

[0030] Figure 3A and 3B each is an illustration of a side-by-side fiber arrangement with a shell according to some examples;

[0031] Figure 4 is a diagram of a core layer according to some examples;

[0032] Figure 5 illustrates methods that may be used to produce a core layer according to some examples;

[0033] Figure 6 Another method that can be used to produce a core layer according to certain examples is shown;

[0034] Figure 7 is a diagram of an article comprising a core layer and an outer skin layer according to some examples;

[0035] Figure 8 is a diagram of an article comprising a core layer and two outer skin layers according to some examples; and

[0036] Fig. 9 is an illustration of an article including a core layer, an outer skin layer, and a decorative layer according to some examples.

[0037] Those of ordinary skill in the art will recognize that the depictions and layers of the drawings are provided for illustration purposes only. Unless clearly described in conjunction with specific illustrations in the description herein, specific thicknesses, material sizes, etc. are not intended to be implied or required. DETAILED DESCRIPTION

[0038] Some examples are methods described herein that can use a combination of thermoplastic materials and different fibers to increase the retention of leavening agents. In some examples, the leavening agent retention can be at least 50 volume % or better in the presence of different fibers and thermoplastic materials. The ability to retain more leavening agent reduces the amount of material required, reduces the cost of producing the article, and can provide better distribution of the leavening agent in the article.

[0039] In certain embodiments, in some cases, the articles produced herein are described as lightweight reinforced thermoplastic (LWRT) articles. Generally speaking, the articles include: a core layer including a web formed of a thermoplastic material, reinforcing fibers, and bicomponent fibers. The presence of a combined material can help retain a bulking agent, such as a microsphere bulking agent, in the web of the core layer.

[0040] In some configurations, the bicomponent fiber of the core layer may include two or more different materials that can be arranged in a variety of different ways. For example, the bicomponent fiber can be configured as a core-shell arrangement, a side-by-side arrangement, or a combination of these arrangements, wherein the shell surrounds the side-by-side arrangement of the fiber. The different fibers can be produced by extrusion, coextrusion, stretching, or in a similar manner for producing fibers. In some instances, the produced fiber can be coated with another material to provide a shell around the core fiber. In the case where there are more than a single fiber in the shell, the fibers can be coaxial, such as remaining unwound, or can be crossed or wound as desired.

[0041] refer to Figure 1, a diagram showing a cross section of a bicomponent fiber through a core-sheath arrangement is shown. The bicomponent fiber 100 includes a core material 110 surrounded by a sheath material 120. Each of the components 110, 120 may not be a fiber in the true sense, but rather the materials of the core 110 and the sheath 120 together form a fiber. Alternatively, each of the materials 110, 120 may be considered a fiber. The sheath material 120 does not have to completely surround the core material 110 or be symmetrical. Without wishing to be bound by any particular theory, the sheath material 120 is selected to be compatible with a thermoplastic material, such as a thermoplastic resin, used to produce the core layer. For example, the melting point of the sheath material 120 may be approximately the same or the same as the melting point of the thermoplastic material of the core layer. In some examples, the melting points of the sheath material 120 and the thermoplastic material may differ by about one degree Celsius to about ten degrees Celsius and the materials may still be considered compatible.

[0042] In certain embodiments, the core material 110 generally has a higher melting point than the shell material 120 and the thermoplastic material. For example, when forming the core layer, the shell material 120 and the thermoplastic material may melt or soften to form a web of the core layer. The core material 110 generally remains solid and does not melt or soften to any significant extent during material processing to form the core layer.

[0043] In some examples, the melting point of the core material 110 is at least fifteen degrees Celsius higher than the melting point of the shell material 120 or the melting point of the thermoplastic material. In some examples, the melting point of the core material 110 is at least twenty degrees Celsius higher than the melting point of the shell material 120 or the melting point of the thermoplastic material. In other examples, the melting point of the core material 110 is at least twenty-five degrees Celsius higher than the melting point of the shell material 120 or the melting point of the thermoplastic material. In other examples, the melting point of the core material 110 is at least thirty degrees Celsius higher than the melting point of the shell material 120 or the melting point of the thermoplastic material. In some examples, the melting point of the core material 110 is at least thirty-five degrees Celsius higher than the melting point of the shell material 120 or the melting point of the thermoplastic material. In some embodiments, the melting point of the core material 110 is at least forty degrees Celsius higher than the melting point of the shell material 120 or the melting point of the thermoplastic material. In other embodiments, the melting point of the core material 110 is at least forty-five degrees Celsius higher than the melting point of the shell material 120 or the melting point of the thermoplastic material. In other embodiments, the melting point of the core material 110 is at least fifty degrees Celsius higher than the melting point of the shell material 120 or the melting point of the thermoplastic material.

[0044] In certain configurations, the materials present in the shell 120 and the core 110 are not the same materials. For example, the shell material 120 may include a polyolefin, and the core material 110 may include a material having a melting point higher than the melting point of the polyolefin of the shell material 120. In other cases, the core material 110 may include a polyester, a polyamide, or a copolyamide, and the shell material 120 may include a material having a melting point lower than the melting point of the polyester, polyamide, or copolyamide in the core material 110. In additional examples, the shell material 120 may include a polyolefin, and the core material 110 may include a polyester, a polyamide, or a copolyamide. In some examples, the shell material 120 includes a polyolefin, and the core material 110 includes a polyester. In other examples, the shell material 120 includes a polyolefin, and the core material 110 includes a polyamide. In some examples, the shell material 120 includes a polyolefin, and the core material includes a copolyamide.

[0045] In some examples, the polyolefin of the shell material 120 may be polyethylene, polypropylene, or other olefin polymers and copolymers. In some embodiments, the polyolefin material of the shell 120 may be considered to be a linear low-density polyolefin. For example, the polyolefin material of the shell 120 may be a linear low-density polyethylene (LLDPE) or a low-density polyethylene (LDPE). Although the exact material properties may vary, the density of the linear low-density polyethylene may be from about 0.91 g / cm3 to about 0.94 g / cm3. In some examples, the melting point of the LLDPE or LDPE may be at least fifteen degrees Celsius lower than the melting point of the core material 110. In certain examples, the melting point of the LLDPE or LDPE may be at least twenty degrees Celsius lower than the melting point of the core material 110. In other examples, the melting point of the LLDPE or LDPE may be at least twenty-five degrees Celsius lower than the melting point of the core material 110. In certain examples, the melting point of the LLDPE or LDPE may be at least thirty degrees Celsius lower than the melting point of the core material 110. In other examples, the melting point of the LLDPE or LDPE may be at least thirty-five degrees Celsius lower than the melting point of the core material 110. In certain examples, the melting point of the LLDPE or LDPE may be at least forty degrees Celsius lower than the melting point of the core material 110. In other examples, the melting point of the LLDPE or LDPE may be at least forty-five degrees Celsius lower than the melting point of the core material 110. In some examples, the melting point of the LLDPE or LDPE may be at least fifty degrees Celsius lower than the melting point of the core material 110.

[0046] In other examples, the core material 110 may include: a polyester including terephthalate monomer units. For example, the polyester may be polyethylene terephthalate, polybutylene terephthalate, or polynaphthyl terephthalate. In certain examples, the melting point of the polyester including terephthalate monomer units in the core material 110 may be at least fifteen degrees higher than the melting point of the material in the shell material 120. In some examples, the melting point of the polyester including terephthalate monomer units in the core material 110 may be at least twenty degrees higher than the melting point of the material in the shell material 120. In certain examples, the melting point of the polyester including terephthalate monomer units in the core material 110 may be at least twenty-five degrees higher than the melting point of the material in the shell material 120. In other examples, the melting point of the polyester including terephthalate monomer units in the core material 110 may be at least thirty degrees higher than the melting point of the material in the shell material 120. In certain examples, the melting point of the polyester containing terephthalate monomer units in the core material 110 may be at least thirty-five degrees higher than the melting point of the material in the shell material 120. In some examples, the melting point of the polyester containing terephthalate monomer units in the core material 110 may be at least forty degrees higher than the melting point of the material in the shell material 120. In other examples, the melting point of the polyester containing terephthalate monomer units in the core material 110 may be at least forty-five degrees higher than the melting point of the material in the shell material 120. In additional examples, the melting point of the polyester containing terephthalate monomer units in the core material 110 may be at least fifty degrees higher than the melting point of the material in the shell material 120.

[0047] In some embodiments, the core material 110 may include a polyamide or a copolyamide. For example, the core material 110 may include nylon, nylon 66, aramid, polyesteramide, polyetheramide, polyetheresteramide, or other polyamide-containing copolymers. In some instances, the melting point of the polyamide or copolyamide in the core material 110 may be at least fifteen degrees higher than the melting point of the material in the shell material 120. In some instances, the melting point of the polyamide or copolyamide in the core material 110 may be at least twenty degrees higher than the melting point of the material in the shell material 120. In some instances, the melting point of the polyamide or copolyamide in the core material 110 may be at least twenty-five degrees higher than the melting point of the material in the shell material 120. In other instances, the melting point of the polyamide or copolyamide in the core material 110 may be at least thirty degrees higher than the melting point of the material in the shell material 120. In some instances, the melting point of the polyamide or copolyamide in the core material 110 may be at least thirty-five degrees higher than the melting point of the material in the shell material 120. In some examples, the melting point of the polyamide or copolyamide in the core material 110 may be at least forty degrees higher than the melting point of the material in the shell material 120. In other examples, the melting point of the polyamide or copolyamide in the core material 110 may be at least forty-five degrees higher than the melting point of the material in the shell material 120. In additional examples, the melting point of the polyamide or copolyamide in the core material 110 may be at least fifty degrees higher than the melting point of the material in the shell material 120.

[0048] In some examples, the shell material 120 may include polyethylene, such as LLDPE, and the core material 110 may include polyester or polyamide. For example, the core material 110 may include nylon, polyethylene terephthalate, polybutylene terephthalate, polynaphthyl terephthalate, or a combination thereof. In some examples, the melting point of the polyester or polyamide in the core material 110 may be at least fifteen degrees higher than the melting point of the polyethylene material in the shell material 120. In some examples, the melting point of the polyester or polyamide in the core material 110 may be at least twenty degrees higher than the melting point of the polyethylene material in the shell material 120. In some examples, the melting point of the polyester or polyamide in the core material 110 may be at least twenty-five degrees higher than the melting point of the polyethylene material in the shell material 120. In other examples, the melting point of the polyester or polyamide in the core material 110 may be at least thirty degrees higher than the melting point of the polyethylene material in the shell material 120. In certain examples, the melting point of the polyester or polyamide in the core material 110 may be at least thirty-five degrees higher than the melting point of the polyethylene material in the shell material 120. In some examples, the melting point of the polyester or polyamide in the core material 110 may be at least forty degrees higher than the melting point of the polyethylene material in the shell material 120. In other examples, the melting point of the polyester or polyamide in the core material 110 may be at least forty-five degrees higher than the melting point of the polyethylene material in the shell material 120. In additional examples, the melting point of the polyester or polyamide in the core material 110 may be at least fifty degrees higher than the melting point of the polyethylene material in the shell material 120.

[0049] In other cases, the bicomponent fibers present in the LWRT article may comprise a side-by-side fiber arrangement. Figure 2 , shows a diagram showing a cross-section of a bicomponent fiber through a side-by-side fiber arrangement. The bicomponent fiber 200 includes a first fiber 210 arranged to one side of a second fiber 220. The fibers 210, 220 may be wound around each other or may remain unwound and extend generally coaxially with each other throughout the fiber 200. Without wishing to be bound by any particular theory, the melting point of the material in one of the fibers 210, 220 is generally about the same as or the same as the melting point of the thermoplastic material of the core layer. In some examples, the melting points of one of the fibers 210, 220 and the thermoplastic material may differ by about one degree Celsius to about ten degrees Celsius, and the materials may still be considered compatible.

[0050] In certain embodiments, the melting point of fiber 210 is usually higher than another fiber 220 and the thermoplastic material. For example, when forming the core layer, the fiber 220 and the thermoplastic material can melt or soften to form a web of the core layer. The fiber 210 usually remains solid and does not melt or soften to any significant extent during the material processing to form the core layer. In certain examples, the melting point of fiber 210 is at least 15 degrees Celsius higher than the melting point of fiber 220 or the melting point of the thermoplastic material. In some examples, the melting point of fiber 210 is at least 20 degrees Celsius higher than the melting point of fiber 220 or the melting point of the thermoplastic material. In other examples, the melting point of fiber 210 is at least 25 degrees Celsius higher than the melting point of fiber 220 or the melting point of the thermoplastic material. In other examples, the melting point of fiber 210 is at least 30 degrees Celsius higher than the melting point of fiber 220 or the melting point of the thermoplastic material. In some examples, the melting point of fiber 210 is at least thirty-five degrees Celsius higher than the melting point of fiber 220 or the melting point of the thermoplastic material. In some embodiments, the melting point of fiber 210 is at least forty degrees Celsius higher than the melting point of fiber 220 or the melting point of the thermoplastic material. In other embodiments, the melting point of fiber 210 is at least forty-five degrees Celsius higher than the melting point of fiber 220 or the melting point of the thermoplastic material. In other embodiments, the melting point of fiber 210 is at least fifty degrees Celsius higher than the melting point of fiber 220 or the melting point of the thermoplastic material.

[0051] In certain configurations, the materials present in the fibers 210, 220 are not the same material. For example, the fibers 220 may include a polyolefin, and the fibers 210 may include a material having a melting point higher than the melting point of the polyolefin of the shell material 120. In other cases, the fibers 210 may include a polyester, a polyamide, or a copolyamide, and the fibers 220 may include a material having a melting point lower than the melting point of the polyester, polyamide, or copolyamide in the fibers 210. In additional examples, the fibers 220 may include a polyolefin, and the fibers 210 may include a polyester, a polyamide, or a copolyamide. In some examples, the fibers 220 include a polyolefin, and the fibers 210 include a polyester. In other examples, the fibers 220 include a polyolefin, and the fibers 210 include a polyamide. In some examples, the fibers 220 include a polyolefin, and the fibers 210 include a copolyamide.

[0052] In some examples, the polyolefin of fiber 220 may be polyethylene, polypropylene, or other olefin polymers and copolymers. In some embodiments, the polyolefin material of fiber 220 may be considered to be a linear low-density polyolefin. For example, the polyolefin material of fiber 220 may be a linear low-density polyethylene (LLDPE) or a low-density polyethylene (LDPE). Although the exact material properties may vary, the density of linear low-density polyethylene may be about 0.91 g / cm3 to about 0.94 g / cm3. In some examples, the melting point of LLDPE or LDPE may be at least fifteen degrees Celsius lower than the melting point of fiber 210. In certain examples, the melting point of LLDPE or LDPE may be at least twenty degrees Celsius lower than the melting point of fiber 210. In other examples, the melting point of LLDPE or LDPE may be at least twenty-five degrees Celsius lower than the melting point of fiber 210. In certain examples, the melting point of LLDPE or LDPE may be at least thirty degrees Celsius lower than the melting point of core material 110. In other examples, the melting point of the LLDPE or LDPE may be at least thirty-five degrees Celsius lower than the melting point of the fiber 210. In certain examples, the melting point of the LLDPE or LDPE may be at least forty degrees Celsius lower than the melting point of the fiber 210. In other examples, the melting point of the LLDPE or LDPE may be at least forty-five degrees Celsius lower than the melting point of the fiber 210. In some examples, the melting point of the LLDPE or LDPE may be at least fifty degrees Celsius lower than the melting point of the fiber 210.

[0053] In other examples, the fiber 210 may include: a polyester including terephthalate monomer units. For example, the polyester may be polyethylene terephthalate, polybutylene terephthalate, or polynaphthyl terephthalate. In certain examples, the melting point of the polyester including terephthalate monomer units in the fiber 210 may be at least fifteen degrees higher than the melting point of the material in the fiber 220. In some examples, the melting point of the polyester including terephthalate monomer units in the fiber 210 may be at least twenty degrees higher than the melting point of the material in the fiber 220. In certain examples, the melting point of the polyester including terephthalate monomer units in the fiber 210 may be at least twenty-five degrees higher than the melting point of the material in the fiber 220. In other examples, the melting point of the polyester including terephthalate monomer units in the fiber 210 may be at least thirty degrees higher than the melting point of the material in the fiber 220. In certain examples, the melting point of the polyester including terephthalate monomer units in the fiber 210 may be at least thirty-five degrees higher than the melting point of the material in the fiber 220. In some examples, the melting point of the polyester containing terephthalate monomeric units in fiber 210 may be at least forty degrees higher than the melting point of the material in fiber 220. In other examples, the melting point of the polyester containing terephthalate monomeric units in fiber 210 may be at least forty-five degrees higher than the melting point of the material in fiber 220. In additional examples, the melting point of the polyester containing terephthalate monomeric units in fiber 210 may be at least fifty degrees higher than the melting point of the material in fiber 220.

[0054] In some embodiments, fiber 210 may include a polyamide or copolyamide. For example, fiber 210 may include nylon, nylon 66, aramid, polyesteramide, polyetheramide, polyetheresteramide, or other copolymers containing polyamide. In some examples, the melting point of the polyamide or copolyamide in fiber 210 may be at least fifteen degrees higher than the melting point of the material in fiber 220. In some examples, the melting point of the polyamide or copolyamide in fiber 210 may be at least twenty degrees higher than the melting point of the material in fiber 220. In some examples, the melting point of the polyamide or copolyamide in fiber 210 may be at least twenty-five degrees higher than the melting point of the material in fiber 220. In other examples, the melting point of the polyamide or copolyamide in fiber 210 may be at least thirty degrees higher than the melting point of the material in fiber 220. In some examples, the melting point of the polyamide or copolyamide in fiber 210 may be at least thirty-five degrees higher than the melting point of the material in fiber 220. In some examples, the melting point of the polyamide or copolyamide in fiber 210 may be at least forty degrees higher than the melting point of the material in fiber 220. In other examples, the melting point of the polyamide or copolyamide in fiber 210 may be at least forty-five degrees higher than the melting point of the material in fiber 220. In additional examples, the melting point of the polyamide or copolyamide in fiber 210 may be at least fifty degrees higher than the melting point of the material in fiber 220.

[0055] In some examples, fiber 220 may include polyethylene, such as LLDPE, and fiber 210 may include polyester or polyamide. For example, fiber 210 may include nylon, polyethylene terephthalate, polybutylene terephthalate, polynaphthyl terephthalate, or a combination thereof. In some examples, the melting point of the polyester or polyamide in fiber 210 may be at least fifteen degrees higher than the melting point of the polyethylene material in fiber 220. In some examples, the melting point of the polyester or polyamide in core fiber 210 may be at least twenty degrees higher than the melting point of the polyethylene material in fiber 220. In some examples, the melting point of the polyester or polyamide in fiber 210 may be at least twenty-five degrees higher than the melting point of the polyethylene material in fiber 220. In other examples, the melting point of the polyester or polyamide in fiber 210 may be at least thirty degrees higher than the melting point of the polyethylene material in fiber 220. In some examples, the melting point of the polyester or polyamide in fiber 210 may be at least thirty-five degrees higher than the melting point of the polyethylene material in fiber 220. In some examples, the melting point of the polyester or polyamide in fiber 210 may be at least forty degrees higher than the melting point of the polyethylene material in fiber 220. In other examples, the melting point of the polyester or polyamide in fiber 210 may be at least forty-five degrees higher than the melting point of the polyethylene material in fiber 220. In additional examples, the melting point of the polyester or polyamide in fiber 210 may be at least fifty degrees higher than the melting point of the polyethylene material in fiber 220.

[0056] refer to Figure 3A , shows a diagram showing a cross section through a side-by-side fiber arrangement with a shell surrounding a bicomponent fiber of the side-by-side fiber arrangement. For example, fiber 300 includes a shell 320 surrounding two fibers 310, 315. In Figure 3A In the embodiment, fibers 310, 315 may include the same or similar components. For example, each of fibers 310, 315 may independently include and combine Figure 1 The same materials described for core material 110 in FIG. 1 , for example, each of fibers 310 , 315 may independently comprise polyamide, polyester, or other polymers.

[0057] In certain embodiments, the shell material 320 may include a polyolefin. In some examples, the polyolefin of the shell material 320 may be polyethylene, polypropylene, or other olefin polymers and copolymers. In some embodiments, the polyolefin material of the shell 320 may be considered to be a linear low-density polyolefin. For example, the polyolefin material of the shell 320 may be a linear low-density polyethylene (LLDPE) or a low-density polyethylene (LDPE). Although the exact material properties may vary, the density of the linear low-density polyethylene may be from about 0.91 g / cm3 to about 0.94 g / cm3. In some examples, the melting point of the LLDPE or LDPE may be at least fifteen degrees Celsius lower than the melting point of the fibers 310, 315. In certain examples, the melting point of the LLDPE or LDPE may be at least twenty degrees Celsius lower than the melting point of the fibers 310, 315. In other examples, the melting point of the LLDPE or LDPE may be at least twenty-five degrees Celsius lower than the melting point of the fibers 310, 315. In certain examples, the melting point of the LLDPE or LDPE may be at least thirty degrees Celsius lower than the melting point of the fibers 310, 315. In other examples, the melting point of the LLDPE or LDPE may be at least thirty-five degrees Celsius lower than the melting point of the fibers 310, 315. In certain examples, the melting point of the LLDPE or LDPE may be at least forty degrees Celsius lower than the melting point of the fibers 310, 315. In other examples, the melting point of the LLDPE or LDPE may be at least forty-five degrees Celsius lower than the melting point of the fibers 310, 315. In some examples, the melting point of the LLDPE or LDPE may be at least fifty degrees Celsius lower than the melting point of the fibers 310, 315.

[0058] In some examples, the fibers 310, 315 may independently include polyester or polyamide. In some cases, the fibers 310, 315 may independently include nylon, polyethylene terephthalate, polybutylene terephthalate, polynaphthyl terephthalate, or a combination thereof. In some examples, the melting point of the polyester or polyamide in the fibers 310, 315 may be at least fifteen degrees higher than the melting point of the polyethylene material in the shell material 320. In some examples, the melting point of the polyester or polyamide in the fibers 310, 315 may be at least twenty degrees higher than the melting point of the polyethylene material in the shell material 320. In some examples, the melting point of the polyester or polyamide in the fibers 310, 315 may be at least twenty-five degrees higher than the melting point of the polyethylene material in the shell material 320. In other examples, the melting point of the polyester or polyamide in the fibers 310, 315 may be at least thirty degrees higher than the melting point of the polyethylene material in the shell material 320. In certain examples, the melting point of the polyester or polyamide in the fibers 310, 315 may be at least thirty-five degrees higher than the melting point of the polyethylene material in the shell material 320. In some examples, the melting point of the polyester or polyamide in the fibers 310, 315 may be at least forty degrees higher than the melting point of the polyethylene material in the shell material 320. In other examples, the melting point of the polyester or polyamide in the fibers 310, 315 may be at least forty-five degrees higher than the melting point of the polyethylene material in the shell material 320. In additional examples, the melting point of the polyester or polyamide in the fibers 310, 315 may be at least fifty degrees higher than the melting point of the polyethylene material in the shell material 320.

[0059] Although Figure 3A Two side-by-side fibers are shown that may contain the same composition, but this configuration is not necessary. Figure 3B , showing fibers 360, 365 arranged side by side surrounded by a shell 370. The fibers 360, 365 do not have to have the same composition as each other, but the melting point of each of the fibers 360, 365 is generally higher than the melting point of the shell 370 in the fiber arrangement 350. In one configuration, one of the fibers 360, 365 is a reinforcing fiber as mentioned below, such as an inorganic fiber, such as glass fiber, graphite fiber, carbon fiber, etc., and the other of the fibers 360, 365 is an organic fiber, such as containing one or more covalently bonded carbon-hydrogen groups. By packaging inorganic and organic fibers in a shell, the addition of fibers during material processing to form a core layer can be simplified. In other examples, the fibers 360, 365 can each be an organic fiber with different compositions.

[0060] In certain embodiments, the shell material 370 may include a polyolefin. In some examples, the polyolefin of the shell material 370 may be polyethylene, polypropylene, or other olefin polymers and copolymers. In some embodiments, the polyolefin material of the shell 370 may be considered to be a linear low-density polyolefin. For example, the polyolefin material of the shell 370 may be a linear low-density polyethylene (LLDPE) or a low-density polyethylene (LDPE). Although the exact material properties may vary, the density of the linear low-density polyethylene may be from about 0.91 g / cm3 to about 0.94 g / cm3. In some examples, the melting point of the LLDPE or LDPE may be at least fifteen degrees Celsius lower than the melting point of the fibers 360, 365. In certain examples, the melting point of the LLDPE or LDPE may be at least twenty degrees Celsius lower than the melting point of the fibers 360, 365. In other examples, the melting point of the LLDPE or LDPE may be at least twenty-five degrees Celsius lower than the melting point of the fibers 360, 365. In certain examples, the melting point of the LLDPE or LDPE may be at least thirty degrees Celsius lower than the melting point of the fibers 360, 365. In other examples, the melting point of the LLDPE or LDPE may be at least thirty-five degrees Celsius lower than the melting point of the fibers 360, 365. In certain examples, the melting point of the LLDPE or LDPE may be at least forty degrees Celsius lower than the melting point of the fibers 360, 365. In other examples, the melting point of the LLDPE or LDPE may be at least forty-five degrees Celsius lower than the melting point of the fibers 360, 365. In some examples, the melting point of the LLDPE or LDPE may be at least fifty degrees Celsius lower than the melting point of the fibers 360, 365.

[0061] In some examples, the fibers 360 and 365 may independently include polyester or polyamide, or one of the fibers 360 and 365 may be an inorganic reinforcing fiber. In some cases, the fibers 360 and 365 may independently include nylon, polyethylene terephthalate, polybutylene terephthalate, polynaphthyl terephthalate, or a combination thereof. In some examples, the melting point of the material in the fibers 360 and 365 may be at least fifteen degrees higher than the melting point of the polyethylene material in the shell material 370. In some examples, the melting point of the material in the fibers 360 and 365 may be at least twenty degrees higher than the melting point of the polyethylene material in the shell material 370. In some examples, the melting point of the material in the fibers 360 and 365 may be at least twenty-five degrees higher than the melting point of the polyethylene material in the shell material 370. In other examples, the melting point of the material in the fibers 360 and 365 may be at least thirty degrees higher than the melting point of the polyethylene material in the shell material 370. In certain examples, the melting point of the material in the fibers 360, 365 may be at least thirty-five degrees higher than the melting point of the polyethylene material in the shell material 320. In some examples, the melting point of the material in the fibers 360, 365 may be at least forty degrees higher than the melting point of the polyethylene material in the shell material 370. In other examples, the melting point of the material in the fibers 360, 365 may be at least forty-five degrees higher than the melting point of the polyethylene material in the shell material 370. In additional examples, the melting point of the material in the fibers 360, 365 may be at least fifty degrees higher than the melting point of the polyethylene material in the shell material 370.

[0062] In certain embodiments and with reference to Figure 4, showing core layer 410 comprising thermoplastic material, reinforcing fibers, bicomponent fibers and a leavening agent. Although not in all configurations, the leavening agent is typically captured in the voids or pores of core layer 410. Core layer 410 may first be formed as a prepreg, which is typically a precursor to core layer 410 and does not have to be fully formed. For ease of illustration, the core layer is described below, but the properties of the core layer may also be the same as the prepreg. Core layer 410 includes a porous structure to allow gas to flow through the core layer. For example, the void content or porosity of the core layer can be 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 porosity or void content of the core layer 410 is greater than 0%, such as not fully consolidated, up to about 95%. Unless otherwise specified, reference to a core layer of a certain void content or porosity is based on the total volume of the core layer, and is not necessarily the total volume of the core layer plus any other materials or layers coupled to the core layer.

[0063] In certain embodiments, the thermoplastic material of core layer 410 may at least partially comprise one or more of the following: polyethylene, polypropylene, polystyrene, acrylonitrile styrene, butadiene, polyethylene terephthalate, polybutylene terephthalate, polybutylene tetrachloride, 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 such as Bayer's The high heat polycarbonate of PC, high temperature nylon and silicone, and these materials each other or with other polymer materials alloy and blend can use the original thermoplastic material for forming the core layer in powder form, resin form, rosin form, fiber form or other suitable form. Various forms of exemplary thermoplastic materials are described herein, and are also described in U.S. Publication No. 20130244528 and US20120065283, for example. The exact amount of thermoplastic material present in the core layer 410 can vary, and the illustrative amount is in the range of about 20 weight % to about 80 weight %. As mentioned in this article, the material of the core layer 410 can be selected so that its melting point is approximately the same as one of the materials in the bicomponent fiber and is lower than the melting point of another material in the bicomponent fiber. The illustrative melting point range of the thermoplastic material includes, but is not limited to, about 120 degrees Celsius to about 260 degrees Celsius. If necessary, a thermoplastic material that melts between 100 degrees Celsius and 315 degrees Celsius can also be used.

[0064] In some examples, the reinforcing fibers of the core layer 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 high melt flow index resin suitable for use as fibers, natural fibers (such as hemp, sisal, jute, flax, coconut shell fibers, kenaf, and cellulose fibers), mineral fibers (such as basalt, mineral wool (such as rock 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 cases, a type of reinforcing fiber may be used together with the mineral fiber, for example, a fiber formed by spinning or stretching a molten mineral. Illustrative mineral fibers include, but are not limited to, mineral wool fibers, glass wool fibers, asbestos fibers, and ceramic wool fibers. In some examples, the reinforcing fibers may be selected to be inorganic fibers, such as fibers that do not include covalently bonded carbon-hydrogen groups.

[0065] In certain embodiments, any of the aforementioned reinforcing fibers can be chemically treated before use to provide the required functional groups or to give the fiber other physical properties. The total fiber content (reinforcing fibers + bicomponent fibers) in the core layer can be about 20% by weight to about 90% by weight of the core layer, more specifically, about 30% by weight to about 70% by weight of the core layer. Typically, the total fiber content of the composite material product comprising the core layer is about 20% by weight to about 90% by weight of the composite material, more specifically about 30% by weight to about 80% by weight, such as about 40% by weight to about 70% by weight. The specific size and / or orientation of the reinforcing fibers used may depend at least in part on the required properties of the polymer material used and / or the resulting core layer. In view of the benefits of the present disclosure, those of ordinary skill in the art will easily select the additional type, fiber size and quantity of suitable fibers. In a non-limiting illustration, the diameter of the reinforcing fibers dispersed in the thermoplastic material to provide the core layer is generally greater than about 5 microns, more specifically about 5 microns to about 22 microns, and a length of about 5mm to about 200mm. More specifically, the reinforcing fiber diameter may be from about 5 microns to about 22 microns, and the fiber length may be from about 51 mm to about 75 mm. In some configurations, the flame retardant material may be present in fiber form. For example, the core layer may include a thermoplastic material, reinforcing fibers, bicomponent fibers, and fibers including a flame retardant material.

[0066] In some configurations, core layer 410 may be substantially halogen-free or halogen-free layer to meet the restrictions of harmful substances required for certain applications. In other cases, core layer 410 may include halogenated flame retardants (which may be present in flame retardant materials, or may be added in addition to flame retardant materials), for example, halogenated flame retardants comprising one or more of F, Cl, Br, I and At or compounds including such halogens, such as tetrabromobisphenol A polycarbonate or monohalogenated, dihalogenated, trihalogenated or tetrahalogenated polycarbonates. In some cases, the thermoplastic material used in core layer 410 may include one or more halogens to impart certain flame retardancy without the need to add another flame retardant. For example, in addition to the presence of flame retardant materials, thermoplastic materials may also be halogenated, or the original thermoplastic material may be halogenated and used alone. In the presence of halogenated flame retardants, it is desirable that the flame retardant exists in a flame retardant amount, which may vary according to other components present. For example, the halogenated flame retardant present in addition to the flame retardant material can be about 0.1 wt % to about 40 wt % (based on the weight of the prepreg), more specifically about 0.1 wt % to about 15 wt %, for example, about 5 wt % to about 15 wt % is present. If necessary, two different halogenated flame retardants can be added to the core layer 410. In other cases, non-halogenated flame retardants can be added, such as, for example, flame retardants comprising one or more of N, P, As, Sb, Bi, S, Se and Te. In certain embodiments, non-halogenated flame retardants may include phosphating materials, so the core layer 410 can be more environmentally friendly. In the presence of non-halogenated or substantially halogen-free flame retardants, it is desired that the flame retardant is present in a flame retardant amount, which can 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 40% by weight (based on the weight of the prepreg), more specifically in an amount of about 5% to about 40% by weight, such as about 5% to about 15% by weight, based on the weight of the core layer. If desired, two different substantially halogen-free flame retardants can be added to the core layer 410. In some cases, the core layer 410 described herein may include one or more halogenated flame retardants and one or more substantially halogen-free flame retardants. When there are two different flame retardants, a combination of the two flame retardants can be present in a flame retardant amount, which can vary according to the other components present. For example, the total weight of the flame retardant present can be about 0.1% to about 40% by weight (based on the weight of the prepreg or core), more specifically in an amount of about 5% to about 40% by weight, such as about 2% to about 14% by weight, based on the weight of the core layer. The flame retardants used in the core layers described herein may be added to the mixture comprising the thermoplastic material, bicomponent fibers, and reinforcing fibers (before the mixture is disposed on a screen or other processing assembly) or may be added after the core layer 410 is formed.

[0067] As mentioned herein, core layer 410 may include a leavening agent present in the pores or voids of the core layer. The leavening agent may take the form of expandable microspheres, the volume of which may increase upon exposure to heat or other stimuli. For example, the thickness of core layer 410 may be increased by expansion of the leavening agent. The exact amount of leavening agent present in core layer 410 may vary, but illustrative amounts include, but are not limited to, about 0.5% by weight to about 15% by weight.

[0068] In certain embodiments, the exact amount of bicomponent fibers in the core layer described herein may vary. Generally speaking, the weight percentage of bicomponent fibers in the core layer may vary in the range of about 2 wt % to about 30 wt %. In some instances, there are approximately the same amount of bicomponent fibers and reinforcing fibers in the core layer.

[0069] In certain embodiments, the core layer and / or article described herein may be generally as Figure 5The preparation of reinforcing fiber, bicomponent fiber, bulking agent and thermoplastic material is shown. In order to produce the core layer, thermoplastic material, reinforcing fiber, bicomponent fiber, bulking agent and optional other materials can be added or metered into the dispersed foam in the open-top mixing tank equipped with an impeller in step 510 to provide an aqueous dispersion of the material. Without wishing to be bound by any particular theory, the presence of trapped air pockets of the foam can help disperse reinforcing fiber, bicomponent fiber, thermoplastic material, bulking agent and any other material. In some instances, the dispersed mixture of fiber, bulking agent and thermoplastic can be pumped to the headbox located above the wire section of the paper machine via a distribution manifold. For example, in step 520, the aqueous mixture can be deposited on a moving mesh screen or other supporting element. Then the foam can be removed without removing the fiber, bulking agent or thermoplastic material, while using pressure to provide the dispersed mixture to a moving support, such as a mesh screen, continuously producing a uniform fiber wet web, wherein the bulking agent is captured in the net. At step 530, the wet web may be passed through a dryer at a suitable temperature to reduce the moisture content and melt or soften at least one of the thermoplastic material and the bicomponent fiber to provide a core layer. When the hot web leaves the dryer, an optional surface or outer skin layer, such as a textured film, may be laminated to the web by passing the web of reinforcing fibers, bicomponent fibers, thermoplastic material, bulking agent, and textured film through the nip of a set of heated rollers. If desired, additional layers, such as another film layer, a scrim layer, etc., may also be attached to one or both sides of the web along with the textured film to facilitate easy handling of the produced composite material. The composite material may then be passed through a tension roller and continuously cut (cut) to the desired size for subsequent forming into a final composite product. Further information regarding the preparation of such composite materials, including suitable materials and processing conditions for use in forming such composite materials, is described, for example, in U.S. Patents 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 Publications US 2005 / 0082881; US ​​2005 / 0228108; US 2005 / 0217932; US 2005 / 0215698; US 2005 / 0164023; and US 2005 / 0161865.

[0070] In another configuration, the core layer and / or article described herein may be generally as Figure 6The preparation of the illustrated use of reinforcing fibers, bicomponent fibers and thermoplastic materials. In order to produce the core layer, in step 610, thermoplastic materials, reinforcing fibers, bicomponent fibers and optional other materials can be added or metered into the dispersed foam in the open mixing tank equipped with an impeller to provide an aqueous dispersion. Without wishing to be bound by any particular theory, the presence of trapped air pockets of the foam can help disperse reinforcing fibers, bicomponent fibers, thermoplastic materials and any other materials. In some instances, the dispersed mixture of fibers and thermoplastics can be pumped to a headbox located above the wire section of a paper machine via a distribution manifold. For example, the aqueous mixture can be deposited on a moving mesh screen or other supporting element to provide a wet web in step 620. The foam can then be removed without removing the fibers or thermoplastic materials, while using pressure to provide the dispersed mixture to a moving support, such as a mesh screen, to continuously produce a uniform fiber wet web. The leavening agent can then be deposited or sprayed on the top of the wet web in step 625 to provide a wet web including a leavening agent. In step 630, the wet web containing the deposited bulking agent may be passed through a dryer, optionally under vacuum or by applying pressure, and heated at a suitable temperature to reduce the moisture content and melt or soften at least one of the thermoplastic material and the bicomponent fiber to provide a core layer. When the hot web leaves the dryer, an optional surface or outer skin layer, such as a textured film, may be laminated to the web by passing the web of reinforcing fibers, bicomponent fibers, thermoplastic material, bulking agent, and textured film through the nip of a set of heated rollers. If desired, additional layers, such as another film layer, a scrim layer, etc., may also be attached to one or both sides of the web along with the textured film to facilitate easy handling of the produced composite material. The composite material may then be passed through a tension roller and continuously cut (cut) to the desired size for subsequent forming into a final composite product.

[0071] In certain embodiments, the core layers described herein may be used with skin layers to provide a composite article. Figure 7, the skin layer 720 is shown as being disposed on the first surface of the core layer 410 to provide the composite article 700. The skin layer 720 may include, for example, a film, a scrim (e.g., a fibrous scrim), an inorganic fiberglass (inorganic fiberglass+scrim), a foil, a woven fabric, a nonwoven fabric, or as an inorganic coating, an organic coating, or a thermosetting coating disposed on the core layer. In other cases, the layer 720 may include a limiting oxygen index greater than about 22 as measured according to ISO 4589 dated 1996. In the case where the fibrous scrim is present as the skin layer 720 (or as part of the skin layer 720), the fibrous scrim 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. In the case where the thermosetting coating is present as the layer 720 (or as part of the layer 720), the coating may include at least one of unsaturated polyurethane, vinyl ester, phenolic, and epoxy resin. In the case where an inorganic coating is present as layer 720 (or as part of layer 720), the inorganic coating may include a mineral containing a cation selected from the group consisting of 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 layer 720 (or as part of layer 720), the nonwoven fabric may include a thermoplastic material, a thermosetting binder, an inorganic fiber, a metal fiber, a metallized inorganic fiber, and a metallized synthetic fiber. If desired, an intermediate layer (not shown) may be present between the core layer and the outer skin layer 720. For example, an adhesive layer or a layer of other material may be present between the core layer 410 and the outer skin layer 720.

[0072] In some examples, the composite article may further include a second skin layer disposed on another surface of the core layer. Figure 8, a composite article 800 is shown comprising skin layers 720, 820 sandwiching core layer 410. Layer 820 may be the same as layer 720 or may be different. In some cases, layer 820 may comprise, for example, a film, a scrim (e.g., a fibrous scrim), an inorganic fiberglass (inorganic fiberglass + scrim), a foil, a woven fabric, a nonwoven fabric, or exists as an inorganic coating, an organic coating, or a thermosetting coating disposed on the core layer. In other cases, layer 820 may comprise a limiting oxygen index greater than about 22 as measured according to ISO 4589 dated 1996. In the case where a fibrous scrim is present as layer 820 (or as part of layer 820), the fibrous scrim 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 as layer 820 (or as part of layer 820), the coating may include at least one of unsaturated polyurethane, vinyl ester, phenolic, and epoxy resin. Where an inorganic coating is present as layer 820 (or as part of layer 820), the inorganic coating may include a mineral containing a cation selected from the group consisting of Ca, Mg, Ba, Si, Zn, Ti, and Al, or may include at least one of gypsum, calcium carbonate, and mortar. Where a nonwoven fabric is present as layer 820 (or as part of layer 820), the nonwoven fabric may include a thermoplastic material, a thermosetting binder, an inorganic fiber, a metal fiber, a metallized inorganic fiber, and a metallized synthetic fiber. If desired, an intermediate layer (not shown) may be present between the core layer and the outer skin layer 820. For example, an adhesive layer or a layer of other material may be present between the core layer 410 and the outer skin layer 820.

[0073] In certain configurations, the composite article may include a decorative layer disposed on a surface of the core layer or on an outer skin layer. Fig. 9 , showing an article 900 including a decorative layer 830 disposed on an outer skin layer 720. Although not shown, the decorative layer may be disposed on an opposite surface of the core layer 410 or may be disposed on Figure 8On the outer skin layer 820 shown in . In some examples, the decorative layer 930 can be configured as a decorative layer, a textured layer, a colored layer, etc. For example, the decorative layer 930 can be formed by a thermoplastic film such as polyvinyl chloride, polyolefin, thermoplastic polyester, thermoplastic elastomer, etc. The decorative layer 930 can also be a multilayer structure, which includes a foam core formed by, for example, polypropylene, polyethylene, polyvinyl chloride, polyurethane, etc. Fabrics can be bonded to the foam core, such as woven fabrics made of natural and synthetic fibers, organic fiber woven fabrics after needle punching or the like, raised fabrics, knitwear, flocked fabrics or other such materials. Fabrics can also be bonded to the foam core with thermoplastic adhesives, including pressure-sensitive adhesives and hot melt adhesives, such as polyamides, modified polyolefins, polyurethanes and polyolefins. The decorative layer 930 can also be produced using spunbond, thermal bonding, spunlace, meltblown, wet laying and / or dry laying processes. Insulating or sound absorbing layers may also be bonded to one or more surfaces of the articles described herein, and may be open or closed, such as open-cell foam or closed-cell foam, as desired.

[0074] In certain embodiments, the core layers and articles described herein may be used in architectural and automotive applications, such as headliners, rear window trim, trunk trim, office partitions, cabinet backs, automotive interior panels, or other automotive interior articles.

[0075] Certain specific examples are described to illustrate additional aspects of the techniques described herein.

[0076] Example 1

[0077] Several products were tested for their free leavening ability. Free leavening can be used as a measure of leavening agent retention. Free leavening is measured by punching out discs from the sheet product. The punched discs are heated in an oven at about 200 degrees Celsius to leaven the punched discs. After heating for about five minutes, the leavened discs are removed and allowed to cool on a flat surface for about one minute. The thickness of the leavened discs is then measured.

[0078] The total area density of each of the samples tested was 1000 gsm. Table 1 below shows the materials and amounts used to produce each sample. The difference in free bulk of the bicomponent fibers in the absence (sample HS1) and presence (HS2) of bicomponent fibers is also shown. The bicomponent fibers used core-sheath fibers, where the sheath comprises LLDPE. And the core comprises polyethylene terephthalate.

[0079] Table 1

[0080] sample PP% Glass fiber % Polymer fiber % Leavening agent% Free leavening HS1 43.3％ 52.9％ 0.0％ 5.8％ 9.3mm HS2 43.3％ 43.3％ 9.6％ 5.8％ 11.1mm

[0081] Although the same amount of leavening agent was used to produce both samples, the free loft was increased by more than 20% in the presence of the polymeric bicomponent fibers. These results are consistent with bicomponent fibers providing increased leavening agent retention, which provides increased free loft capability.

[0082] When introducing elements of the examples disclosed herein, the articles "a," "an," "the," and "said" are intended to indicate that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be open ended and mean that there may be additional elements in addition to the listed elements. Given the benefit of this disclosure, one of ordinary skill in the art will recognize that various components in an example may be interchanged or replaced by various components in other examples.

[0083] While certain aspects, examples, and embodiments have been described above, those skilled in the art, given the benefit of this disclosure, will appreciate that additions, substitutions, modifications, and variations of the illustrative aspects, examples, and embodiments disclosed are possible.

Claims

1. A method for producing a porous composite material product, comprising: combining inorganic reinforcing fibers, organic reinforcing fibers, a leavening agent comprising expandable microspheres, and a thermoplastic material in a liquid to produce an aqueous foam, wherein the organic reinforcing fibers comprise a core-shell arrangement, wherein the shell material in the shell of the core-shell arrangement comprises a polyolefin, including polyethylene, polypropylene, or other olefin polymers, and wherein the melting point of the core material of the core-shell arrangement is at least fifteen degrees Celsius higher than the melting point of the polyolefin of the shell material; depositing the aqueous foam onto a moving mesh screen; Removing liquid from the deposited aqueous foam on the moving mesh screen to form a porous network with an open-pore structure formed by the thermoplastic material, the inorganic reinforcing fibers, the organic reinforcing fibers and the leavening agent; wherein, in the presence of the inorganic reinforcing fibers, the organic reinforcing fibers and the thermoplastic material to improve the leavening capacity of the porous composite material product, the leavening agent retention rate is at least 50% by volume; and The formed porous web is pressed to provide the porous composite article.

2. The method of claim 1, wherein negative pressure is provided at the bottom surface of the formed porous web during the deposition of the leavening agent to draw the leavening agent into the interstices of the formed porous web.

3. The method of claim 2, wherein the leavening capacity is increased by 20%.

4. The method of claim 1, wherein the core material of the organic reinforcing fiber comprises polyester. The method according to claim 3 , wherein the polyolefin of the shell material is polyethylene.

6. The method of claim 5, wherein the polyethylene is a linear low density polyethylene.

7. The method of claim 6, wherein the linear low density polyethylene has a density of about 0.91 g / cm 3 to about 0.94 g / cm 3 .

8. The method of claim 4, wherein the polyester comprises one or more of polyethylene terephthalate, polybutylene terephthalate, and polynaphthyl terephthalate.

9. The method of claim 1, wherein the core material of the organic reinforcing fiber comprises polyamide.

10. The method of claim 9, wherein the polyolefin of the shell material is polyethylene.

11. The method of claim 10, wherein the polyethylene is a linear low density polyethylene.

12. The method of claim 11, wherein the linear low density polyethylene has a density of about 0.91 g / cm 3 to about 0.94 g / cm 3 .

13. The method of claim 9, wherein the polyamide comprises a copolyamide.

14. The method of claim 1, wherein the thermoplastic material comprises polyolefin, the inorganic reinforcing fibers comprise glass fibers, and the core material of the organic reinforcing fibers comprises polyester.

15. The method of claim 14, wherein the polyolefin of the thermoplastic material is polypropylene, the polyolefin of the sheath material is polyethylene, and the polyester of the core material comprises polyethylene terephthalate.

16. The method of claim 1, wherein the thermoplastic material comprises polyolefin, the inorganic reinforcing fibers comprise glass fibers, and the core material of the organic reinforcing fibers comprises polyamide.

17. The method of claim 16, wherein the polyolefin of the thermoplastic material is polypropylene and the polyolefin of the shell material is polyethylene.

18. The method of claim 1, wherein the thermoplastic material comprises polypropylene, the inorganic reinforcing fibers comprise glass fibers, the core material of the organic reinforcing fibers comprises polyester, and the shell material of the organic reinforcing fibers is polyethylene, wherein the melting point of the polyester in the core material is at least fifty degrees Celsius higher than the melting point of the polyethylene in the shell material, and wherein the porosity of the porous composite article is 20% to 80%.

19. The method of claim 1, wherein the thermoplastic material comprises polypropylene, the inorganic reinforcing fibers comprise glass fibers, the core material of the organic reinforcing fibers comprises polyamide, and the shell material of the organic reinforcing fibers is polyethylene, wherein the melting point of the polyamide in the core material is at least fifty degrees Celsius higher than the melting point of the polyethylene in the shell material, and wherein the porosity of the porous composite article is 20% to 80%.

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