Fiber-reinforced resin material, its manufacturing method, and fiber-reinforced resin structure

Abstract

To provide a fiber reinforced resin material that is more resistant to cracking, its manufacturing method, and a fiber-reinforced resin structure.SOLUTION: This fiber reinforced resin material 1 has a laminated structure in which a fiber aggregate layer 12 and a thermoplastic resin layer 11 are alternately located. The fiber aggregate layer 12 is an aggregate of continuous fibers with thermoplastic resin particles attached to a surface, and the fiber reinforced resin material has a higher elongation on one side 1b than on the other side 1a. A fiber reinforced resin structure consists of the fiber reinforced resin material. A manufacturing method for the fiber reinforced resin material includes: a laminating process to laminate a sheet of continuous fiber to be the fiber aggregate layer and a resin sheet to be the thermoplastic resin layer so that a laminated structure is obtained; and a thermo-compression process to heat and compress a laminate obtained through the laminating process in a laminating direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fiber-reinforced resin material, a method for producing the same, and a fiber-reinforced resin structure. More specifically, the present invention relates to a fiber-reinforced resin material using a thermoplastic resin, a method for producing the same, and a fiber-reinforced resin structure. [Background technology]

[0002] Conventionally, composite materials called fiber reinforced plastics and the like are known. In general, fiber reinforced plastics are obtained by using a fiber aggregate such as a glass fiber nonwoven fabric as a core material, covering this core material with a resin (matrix resin) as a matrix material, and then curing it. In this case, thermosetting resins are often used as the matrix resin. Many resins have excellent fluidity in an uncured state, and are selected from the viewpoint of ease of impregnation into the core material. However, thermosetting resins have the disadvantage of becoming more brittle and cracking easily when cured. For this reason, fiber reinforced resin materials and fiber reinforced resin structures that are less likely to crack are required. From this viewpoint, it is expected that thermoplastic resins will be used as the matrix resin.

[0003] From these viewpoints, the following Patent Documents 1 and 2 are known as thermoplastic resins having excellent impact resistance. In addition, the following Patent Document 3 is known as a fiber-reinforced material using a thermoplastic resin having excellent impact resistance as a matrix resin. Furthermore, the following Patent Documents 4 and 5 are known as techniques for improving the affinity between reinforcing fibers and a matrix resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-147646 A [Patent Document 2] International Publication No. 2018-021569 Brochure [Patent Document 3] JP 2018-123284 A [Patent Document 4] JP 2017-82060 A [Patent Document 5] International Publication No. 2017-150702 Brochure Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned Patent Document 1 discloses that in a thermoplastic resin composition obtained by melt-kneading a polyamide resin, a polyolefin resin, and a compatibilizer, excellent impact resistance can be exhibited by using a specified plant-derived polyamide resin as the polyamide resin. The above-mentioned Patent Document 2 discloses that, in a thermoplastic resin composition obtained by melt-kneading a polyamide resin, a polyolefin resin, and a compatibilizer, excellent impact resistance can be exhibited by using a polyolefin resin having an Mn of 350,000 or more and a polyamide resin having a structure in which the number of linear carbon atoms in the hydrocarbon group sandwiched between adjacent amide bonds in the main chain is 5 or less. The above-mentioned Patent Document 3 discloses that by employing a thermoplastic resin composition obtained by melt-kneading a polyamide resin, a polyolefin resin, and a compatibilizer as a matrix resin, it is possible to obtain a fiber-reinforced material and structure that are less likely to crack. The above Patent Documents 4 and 5 disclose that in carbon fiber reinforced plastics, the interfacial adhesion with the thermoplastic resin can be improved by employing carbon fibers having thermoplastic resin particles adsorbed on the surface thereof.

[0006] Although the technique of Patent Document 3 makes it possible to obtain fiber-reinforced materials and structures that are less likely to crack, there is a demand for materials having even better strength properties. The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a fiber-reinforced resin material that is less likely to crack than conventional materials, a method for producing the same, and a fiber-reinforced resin structure. [Means for solving the problem]

[0007] That is, the present invention is as follows. [1] The fiber-reinforced resin material of the present invention is a fiber-reinforced resin material having a laminated structure in which fiber assembly layers and thermoplastic resin layers are alternately positioned, The fiber assembly layer is an assembly of continuous fibers having thermoplastic resin particles attached to the surface thereof, The fiber reinforced resin material has one surface having a higher elongation than the other surface. [2] In the fiber-reinforced resin material of the present invention, the thermoplastic resin layer located on the one surface side and the thermoplastic resin layer located on the other surface side can be different from each other. [3] In the fiber-reinforced resin material of the present invention, the thermoplastic resin constituting the thermoplastic resin layer located on the one surface side may be a composite resin containing polyamide and polyolefin. [4] In the fiber-reinforced resin material of the present invention, the fiber content on the one surface side can be made different from the fiber content on the other surface side. [5] In the fiber-reinforced resin material of the present invention, the continuous fibers may be carbon fibers. [6] In the fiber-reinforced resin material of the present invention, the thermoplastic resin constituting the thermoplastic resin particles may contain polyamide. [7] A fiber-reinforced resin structure of the present invention is characterized in that it is made of the fiber-reinforced resin material of the present invention. [8] The method for producing a fiber-reinforced resin material of the present invention includes a lamination step of laminating a sheet-like material of the continuous fibers that will become the fiber assembly layer and a resin sheet that will become the thermoplastic resin layer so as to obtain the laminated structure; The method further comprises a hot pressing step of hot compressing the laminate obtained through the lamination step in the lamination direction. Effect of the Invention

[0008] The fiber-reinforced resin material and the fiber-reinforced resin structure of the present invention can provide superior crack resistance compared to conventional fiber-reinforced resin materials and structures. In particular, the fiber-reinforced resin material and the fiber-reinforced resin structure can provide a high degree of both bending stress and bending modulus. According to the method for producing a fiber-reinforced resin material of the present invention, it is possible to obtain a fiber-reinforced resin material and a fiber-reinforced resin structure that are more resistant to cracking than conventional methods. [Brief description of the drawings]

[0009] The present invention will be further described in the following detailed description by way of non-limiting examples of exemplary embodiments according to the invention and with reference to the several drawings mentioned, in which like reference numerals refer to like parts throughout the several views of the drawings. [Figure 1] FIG. 2 is an explanatory diagram illustrating one embodiment (a) and another embodiment (b) of a fiber reinforced resin material. [Diagram 2] FIG. 2 is an explanatory diagram of continuous fibers. [Diagram 3] FIG. 1 is an explanatory diagram illustrating an overview of a method for producing a fiber-reinforced resin material. [Figure 4] FIG. 2 is an explanatory diagram of a manufacturing method for one embodiment (laminate structures E and F) of a fiber-reinforced resin material. [Diagram 5] FIG. 5 is an explanatory diagram of a method for producing the fiber-reinforced resin material according to one embodiment, following FIG. 4. [Figure 6] FIG. 2 is an explanatory diagram of a fiber-reinforced resin material used in the experimental examples. [Figure 7] FIG. 2 is an explanatory diagram of a fiber-reinforced resin material having a laminate structure A used in an experimental example. [Figure 8] FIG. 2 is an explanatory diagram of a fiber-reinforced resin material having a laminate structure B used in an experimental example. [Figure 9] FIG. 2 is an explanatory diagram of a fiber-reinforced resin material having a laminated structure C used in an experimental example. [Figure 10] FIG. 2 is an explanatory diagram of a fiber-reinforced resin material having a laminated structure D used in an experimental example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The matters shown herein are for illustrative purposes and are intended to provide an illustrative description of the embodiments of the present invention, with the aim of providing what is believed to be the most effective and easily understandable explanation of the principles and conceptual features of the present invention. In this respect, it is not intended to show structural details of the present invention beyond the extent necessary for a fundamental understanding of the present invention, and the description, taken together with the drawings, will make clear to those skilled in the art how some forms of the present invention may be actually embodied.

[0011] [1] Fiber-reinforced resin material The fiber reinforced resin material (1) of the present invention has a laminated structure in which fiber assembly layers (12) and thermoplastic resin layers (11) are alternately arranged. The fiber assembly layers (12) are an assembly of continuous fibers (121) having thermoplastic resin particles (122) attached to their surfaces. Furthermore, the fiber reinforced resin material (1) of the present invention has a higher elongation on one side (1b) than on the other side (1a) (see Figs. 1 and 2).

[0012] The "fiber assembly layer (12)" (see FIG. 1) is an assembly of continuous fibers 121. The fiber assembly layer 12 may be made only of fibers such as continuous fibers, but may also include a binder resin that bonds the continuous fibers together (prepreg). The binder resin may be the same as or different from the thermoplastic resin constituting the thermoplastic resin layer described below. Furthermore, when the binder resin is a different resin, the binder resin may be a binder resin having a common component resin (e.g., polyamide, polyolefin, etc.) with the thermoplastic resin constituting the thermoplastic resin layer (binder resin having a common component resin), or may not have a common component resin.

[0013] When the fiber assembly layer 12 does not contain a binder resin, the fiber assembly layer 12 can be impregnated with the adjacent thermoplastic resin layer 11 in the fiber assembly layer 12 in the fiber reinforced resin material 1. The fiber assembly layer 12 and the thermoplastic resin layer 11 are firmly integrated by the impregnation of the thermoplastic resin layer 11, and the mechanical properties of the fiber reinforced resin material 1 can be further improved. In particular, since the thermoplastic resin particles 122 are attached to the surface of the continuous fibers 121, the affinity with the thermoplastic resin layer 11 is excellent. Therefore, when the thermoplastic resin layer 11 is melted and flowed to be impregnated, the thermoplastic resin constituting the thermoplastic resin layer 11 can more easily penetrate into the fiber assembly layer 12. When the thermoplastic resin layer 11 is impregnated into the fiber assembly layer 12, the fiber reinforced resin material 1 will have a laminated structure in which the fiber assembly layers 12 impregnated with the thermoplastic resin and the thermoplastic resin layers 11 that remain unimpregnated are arranged alternately. This laminated structure can also be said to be a laminated structure in which the fiber assembly layers 12 and the thermoplastic resin layers 11 are arranged alternately.

[0014] The "continuous fiber (121)" (see FIG. 2) is the fiber assembly layer 12 and its constituent fibers. The fiber assembly layer 12 and the continuous fibers 121 that are its constituent fibers become reinforcing materials in the fiber reinforced resin material 1. The fiber assembly layer 12 is formed by assembling the continuous fibers 121. The continuous fibers 121 have a long fiber length (long fibers). Specifically, the fiber length of the continuous fibers 121 can be 15 mm or more. By having a fiber length of 15 mm or more, the intersections between the continuous fibers can be increased, and therefore the tear strength of the fiber assembly layer 12 can be increased. Furthermore, the fiber length is preferably 50 mm or more, more preferably 100 mm or more, and even more preferably 500 mm or more. The maximum fiber length is not limited, but for example, a structure made of this fiber reinforced resin material can include fibers that are continuous from one end to the other end. In this case, the maximum fiber length is, for example, 1×10 6 It can be made to be less than mm.

[0015] In addition to the continuous fibers, the fiber assembly layer may contain short discontinuous fibers (short fibers). The content of the discontinuous fibers is not limited, but is preferably less than 50% by mass, more preferably 25% by mass or less, and particularly preferably 5% by mass or less, when the total fibers constituting the fiber assembly layer is 100% by mass. The fiber length of the discontinuous fibers is not limited, but may be less than 15 mm.

[0016] The continuous fibers may be assembled in any manner within the fiber assembly layer 12. That is, for example, the continuous fibers may be assembled by being drawn together, may be assembled by weaving like a woven fabric, may be assembled by knitting like a knitted fabric, or may be assembled without being woven like a nonwoven fabric. The fiber assembly layer may be composed of only one continuous fiber layer in which the continuous fibers are arranged in layers, or may be composed of two or more continuous fiber layers.

[0017] The thickness of the fiber assembly layer 12 is not limited, but may be, for example, 0.01 μm to 5000 μm, 0.1 μm to 1000 μm, 1 μm to 500 μm, or 5 μm to 250 μm. The basis weight of the fiber assembly layer is not limited, but may be, for example, 0.1 g / m 2 More than 100000g / m 2 It can be as follows: The thickness of the fiber assembly layer 12 can be measured by observation with a scanning electron microscope. More specifically, the thicknesses of 10 arbitrary points in a still image showing an enlarged cross section of the fiber reinforced resin material in the lamination direction are measured, and the average value of the measurements can be regarded as the layer thickness.

[0018] The material constituting the continuous fibers 121 is not limited, and may be an inorganic material, an organic material, or a combination of these. Examples of inorganic fibers include carbon fibers, activated carbon fibers, glass fibers, ceramic fibers (silicates, titanates, alumina, etc.), metal fibers, boron fibers, etc. These may be used alone or in combination of two or more. Examples of organic fibers include natural fibers and synthetic fibers. These may be used alone or in combination of two or more. Among these, synthetic fibers include fibers formed from synthetic resin into a fiber shape. Examples of such synthetic resin fibers include polyamide resin fibers (aliphatic polyamides (nylon fibers, etc.), aromatic polyamides (aramid fibers, trade name "Kevlar", etc.), polyester resin fibers (aliphatic polyesters, aromatic polyesters (polyethylene terephthalate fibers, polyethylene naphthalate fibers, etc.), polyolefin resin fibers (high molecular weight polyolefins (trade name "Dyneema", etc.), polybenzazole resin fibers (polyparaphenylene benzobisoxazole fibers (trade name "Zylon", etc.)).

[0019] Furthermore, the continuous fibers 121 are preferably fibers having a higher tensile strength, for example, fibers having a tensile strength of 7 cN / dtex or more (usually 50 cN / dtex) according to JIS L1015. Furthermore, the form of the fiber is not limited, and may be a spun yarn, a filament yarn, or a combination of these. Furthermore, a monofilament or a multifilament may be used, or a combination of these may be used.

[0020] Among the above, the fiber reinforced resin material can have particularly excellent performance when carbon fibers are used. The type of carbon fiber is not limited, and examples thereof include PAN (polyacrylonitrile)-based carbon fiber, pitch-based carbon fiber, etc. These may be used alone or in combination of two or more kinds. The number of carbon fibers constituting the carbon fiber bundle (tow) is not limited, and can be, for example, 1000 or more. This number can further be 1000 or more and 50000 or less, further can be 1500 or more and 40000 or less, and further can be 2000 or more and 30000 or less. The thickness of the carbon fibers is not limited, but for example, the average diameter can be 1000 nm or more and 30000 nm or less, and further 1000 nm or more and 10000 nm or less. Although a sizing agent may be attached to the surface of the carbon fiber, it is preferable that the sizing agent is not attached from the viewpoint of improving the adhesion of the thermoplastic resin particles. When a sizing agent is attached to the surface of the carbon fiber, it is preferable to remove the sizing agent using a sizing remover (e.g., acetone, 2-butanone (methyl ethyl ketone), tetrahydrofuran, dichloromethane, dichloroethane, etc.).

[0021] The "thermoplastic resin particles (122)" (hereinafter, simply referred to as "resin particles", see FIG. 2) are particles attached to the surfaces of the continuous fibers 121 that constitute the fiber assembly layer 12. By attaching the resin particles 122 to the fiber surfaces, it is possible to improve the affinity with the thermoplastic resin that constitutes the thermoplastic resin layer 11. In other words, it is possible to further strengthen the integration between the fiber assembly layer 12 and the thermoplastic resin layer 11, and it is possible to reduce the starting point of fracture between these different materials. As a result, when a resin with high elongation is used as the thermoplastic resin that constitutes the thermoplastic resin layer 11, it is possible to more effectively reduce the interfacial separation between the highly elongated thermoplastic resin and the continuous fibers 121, and it is possible to more fully utilize the high elongation properties of the resin.

[0022] Any method may be used for attaching the resin particles 122 to the continuous fibers 121, but for example, when the continuous fibers 121 are electrically conductive fibers, particularly carbon fibers, the method may be performed using the disclosures of JP 2017-82060 A and WO 2017-150702 A. That is, for example, the resin particles can be attached to the continuous fibers by immersing the continuous fibers in (1) a colloidal solution containing resin particles, a nonionic surfactant, an electrolyte, and water, or (2) a colloidal solution containing resin particles, a radical polymerization initiator, and water, while applying a voltage with the continuous fibers as a positive electrode or a negative electrode to perform electrophoresis.

[0023] The size of the resin particles 122 is not limited, but may be, for example, 0.02 μm or more and 0.5 μm or less as an average particle size. Furthermore, from the viewpoint of improving the adsorption to the continuous fibers 121, the average particle size may be 0.02 μm or more and 5 μm or less, 0.02 μm or more and 1 μm or less, or 0.02 μm or more and 0.5 μm or less. The resin particles 122 can be attached to, for example, 30 to 100% by area, and further 60 to 99% by area, of the carbon fiber surface. The average particle size of the resin particles 122 can be measured by observation with a scanning electron microscope. More specifically, in a still image enlarged with a scanning electron microscope, the maximum diameters of any 20 resin particles attached to the continuous fibers 121 are actually measured, and the average value thereof can be regarded as the average particle size.

[0024] There is no limitation on the type of thermoplastic resin constituting the resin particles 122 attached to the continuous fibers 121, and any thermoplastic resin may be used. As this thermoplastic resin, the examples of the thermoplastic resin constituting the thermoplastic resin layer described later can be used in the same way. However, the thermoplastic resin constituting the resin particles 122 and the thermoplastic resin constituting the thermoplastic resin layer may be the same or different.

[0025] In addition, when they are different, they may or may not have affinity, but it is preferable that they have a higher affinity from the viewpoint of improving the mechanical properties of the fiber reinforced resin material. Specifically, it is preferable that the thermoplastic resin constituting the resin particles 122 and the thermoplastic resin constituting the thermoplastic resin layer 11 are the same type of thermoplastic resin, or contain the same type of resin as the component resin. Examples of the same type of thermoplastic resin include polyamides, polyolefins, and polyesters. Examples of the same type of resin as the component resin include a case where the thermoplastic resin constituting the thermoplastic resin layer 11 is a melt-kneaded mixture of polyolefins, polyamides, and a compatibilizer for them, and the thermoplastic resin constituting the resin particles 122 contains polyolefins and / or polyamides.

[0026] The "thermoplastic resin layer (11)" (hereinafter, also simply referred to as the "resin layer", see FIG. 1) is a layer whose resin component is a thermoplastic resin. The resin layer may be composed of only the resin component, but may also contain other components such as a filler in addition to the resin component. The other components will be described later.

[0027] The thickness of the resin layer 11 is not limited, but is preferably 5000 μm or less. The resin layer 11 is a layer located between the fiber assembly layers 12 and is not fiber reinforced. For this reason, the layer thickness is preferably small. By making the layer thickness of the resin layer 11 small, the fiber content in the fiber reinforced resin material 1 can be increased, and the mechanical properties can be improved. Specifically, the thickness can be 0.1 μm or more and 2000 μm or less, 0.2 μm or more and 500 μm or less, 0.3 μm or more and 250 μm or less, or 0.4 μm or more and 190 μm or less. The thickness of the resin layer 11 can be measured by observation with a scanning electron microscope. More specifically, the thicknesses of 10 arbitrary points in a still image of an enlarged cross section of the fiber-reinforced resin material in the lamination direction are measured, and the average value of the measurements can be regarded as the layer thickness.

[0028] The type of thermoplastic resin constituting the resin layer 11 is not limited, and examples thereof include polyamide, polyolefin, polyester, polycarbonate, acrylic resin, fluorine-containing thermoplastic resin, polyimide, polyamideimide, and further, a resin alloy (composite resin) containing two or more of these thermoplastic resins. These may be used alone or in combination of two or more.

[0029] Among the above, the type of polyamide (hereinafter, sometimes simply abbreviated as "PA") is not limited, and examples thereof include PA6, PA66, PA11, PA610, PA612, PA614, PA12, PA6T, PA6I, PA9T, PAM5T, PA1010, PA1012, PA10T, PAMXD6, PA6T / 66, PA6T / 6I, PA6T / 6I / 66, PA6T / 2M-5T, PA9T / 2M-8T, etc. These polyamides may be used alone or in combination of two or more kinds. In addition, in the present fiber-reinforced resin material, from the viewpoints of versatility, impact resistance, processability, etc., PA6, PA66, etc. can be selected from the above-mentioned polyamides. These may be used alone or in combination of two or more. From the viewpoints of environmental friendliness (carbon neutrality) and sustainability, plant-derived polyamides (polyamides using plant-derived monomers) can be selected from the above-mentioned polyamides. Examples of plant-derived polyamides include PA11, PA610, PA612, PA614, PA1010, PA1012, PA10T, etc. These may be used alone or in combination of two or more.

[0030] The molecular weight of the polyamide is not limited, and can be, for example, from 5,000 to 100,000, preferably from 7,500 to 50,000, and more preferably from 10,000 to 50,000. Note that this molecular weight is a weight average molecular weight calculated in terms of polystyrene by gel permeation chromatography (GPC).

[0031] Among the above, the type of polyolefin (hereinafter, sometimes simply abbreviated as "PO") is not limited, and PO includes olefin homopolymers and / or olefin copolymers. In addition, the olefins constituting PO are not limited, and examples thereof include ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene. These may be used alone or in combination of two or more. That is, examples of polyolefins include polyethylene, polypropylene, poly-1-butene, poly-1-hexene, and poly-4-methyl-1-pentene. These polymers may be used alone or in combination of two or more.

[0032] Among the above, polyethylene includes ethylene homopolymers and copolymers of ethylene with other olefins, including ethylene-1-butene copolymers, ethylene-1-hexene copolymers, ethylene-1-octene copolymers, and ethylene-4-methyl-1-pentene copolymers (where 50% or more of the total number of structural units is derived from ethylene). Polypropylene also includes propylene homopolymers and copolymers of propylene and other olefins. Among these, the other olefins constituting the copolymers of propylene and other olefins include the above-mentioned various olefins (excluding propylene). The copolymers of propylene and other olefins may be random copolymers or block copolymers. In the copolymers of propylene and other olefins, 50% or more of the total number of constituent units are derived from propylene.

[0033] The PO referred to here is a PO that has no affinity for PA and has no reactive groups that can react with PA, and in this respect is different from a compatibilizer for PA and PO. In addition, the molecular weight of the PO is not limited, and can be, for example, 10,000 or more and 700,000 or less, 100,000 or more and 600,000 or less, or 200,000 or more and 550,000 or less. This molecular weight is a weight average molecular weight calculated in terms of polystyrene by gel permeation chromatography (GPC). When a homopolymer is used as the polyolefin, the weight average molecular weight value can be converted into the number average molecular weight value.

[0034] Among the above, examples of polyesters include polyethylene terephthalate and polybutylene terephthalate. These may be used alone or in combination of two or more. Among the above, examples of acrylic resins include PMMA, ABS, AS, etc. These may be used alone or in combination of two or more. Among the above, examples of fluorine-containing thermoplastic resins include polytetrafluoroethylene, etc. These may be used alone or in combination of two or more.

[0035] Among the above, the resin alloy containing two or more thermoplastic resins is not limited and may be any combination of thermoplastic resins, but a composite resin (thermoplastic resin) containing polyamide and polyolefin can be selected from the viewpoints of impact resistance, elongation, and processability. The composite resin containing polyamide and polyolefin may be (1) the composite resin disclosed in JP 2013-147646 A, (2) the composite resin disclosed in WO 2018-021569 A, or (3) the composite resin disclosed in JP 2018-123284 A. More specifically, the composite resin disclosed in (1) JP 2013-147646 A is prepared by melt-kneading a polyamide resin, a polyolefin resin, and a compatibilizer, the polyamide resin being at least one plant-derived polyamide resin selected from PA11, PA610, PA614, PA1010, and PA10T, the compatibilizer being an acid-modified olefin-based thermoplastic elastomer, and the thermoplastic resin having a polyamide resin content of 1% by mass or more and 80% by mass or less, a polyolefin resin content of 5% by mass or more and 75% by mass or less, and a compatibilizer content of 1% by mass or more and 30% by mass or less, relative to 100% by mass of the total of the polyamide resin, polyolefin resin, and compatibilizer. The composite resin disclosed in (2) International Publication No. 2018-021569 is a thermoplastic resin composition obtained by blending a polyolefin resin, a polyamide resin, and a modified elastomer having a reactive group with respect to the polyamide resin (i.e., a compatibilizer), in which the polyolefin resin has a number average molecular weight of 350,000 or more, and the polyamide resin is a thermoplastic resin having a structure in which the number of linear carbon atoms in the hydrocarbon group sandwiched between adjacent amide bonds in the main chain is 5 or less. Furthermore, the composite resin disclosed in the above-mentioned (3) JP 2018-123284 A is a thermoplastic resin obtained by blending a polyolefin resin, a polyamide resin, and a modified elastomer (compatibilizer) having a reactive group with respect to the polyamide resin.

[0036] The polyamides used in these composite resins may be the polyamides described above. The polyolefins used in these composite resins may be the polyolefins described above. Furthermore, the compatibilizers used in these composite resins may be the compatibilizers shown below.

[0037] The compatibilizer is a modified elastomer having a reactive group with respect to polyamide resin. This modified elastomer is preferably an elastomer that exhibits affinity with polyamide by utilizing the reactive group and also exhibits affinity with polyolefin separately. That is, the modified elastomer is preferably a compatibilizer that has a reactive group with respect to polyamide and has compatibility with both polyolefin and polyamide. The modified elastomer may be contained in the composite resin as an unreacted modified elastomer, as a reaction product with the polyamide, or in both of these forms.

[0038] Examples of reactive groups possessed by the compatibilizer include an acid anhydride group (-CO-O-OC-), a carboxyl group (-COOH), an epoxy group {-CO (a three-membered ring structure consisting of two carbon atoms and one oxygen atom)}, an oxazoline group (-CHNO), and an isocyanate group (-NCO), etc. These may be used alone or in combination of two or more. The reactive group can be introduced by modification to the elastomer before modification (unmodified elastomer). Specific examples include acid-modified elastomers, epoxy-modified elastomers, and oxazoline-modified elastomers. Among these, acid-modified elastomers are preferred, and more preferably, elastomers modified with acid anhydrides or carboxylic acids. The modified elastomer particularly preferably has an acid anhydride group or a carboxyl group in the side chain or terminal of the molecule. The amount of acid modification is not particularly limited, and for example, the number of acid anhydride groups or carboxyl groups contained in one molecule of the modified elastomer is preferably 1 or more, more preferably 2 to 50, even more preferably 3 to 30, and particularly preferably 5 to 20. These modified elastomers may be used alone or in combination of two or more kinds.

[0039] Examples of the elastomer before modification include olefin-based elastomers, styrene-based elastomers, etc. From the viewpoint of compatibility with polyolefins, olefin-based elastomers are particularly preferred. The olefin elastomer is preferably an α-olefin copolymer containing a structural unit derived from an α-olefin having a carbon number of 3 to 8, and may be an ethylene-α-olefin copolymer, an α-olefin copolymer, an α-olefin-non-conjugated diene copolymer, or an ethylene-α-olefin-non-conjugated diene copolymer. Of these, ethylene-α-olefin copolymers, α-olefin copolymers, and ethylene-α-olefin-non-conjugated diene copolymers are particularly preferred.

[0040] The non-conjugated dienes include linear non-cyclic diene compounds such as 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, and 1,6-hexadiene; and branched non-cyclic diene compounds such as 5-methyl-1,4-hexadiene, 3,7-dimethyl-1,6-octadiene, 5,7-dimethylocta-1,6-diene, 3,7-dimethyl-1,7-octadiene, 7-methylocta-1,6-diene, and dihydromyrcene. alicyclic diene compounds such as tetrahydroindene, methyltetrahydroindene, dicyclopentadiene, bicyclo[2.2.1]-hepta-2,5-diene, 5-methylene-2-norbornene, 5-ethylidene-2-norbornene, 5-propenyl-2-norbornene, 5-isopropylidene-2-norbornene, 5-cyclohexylidene-2-norbornene, and 5-vinyl-2-norbornene.

[0041] Specific examples of the olefin elastomer include ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-1-pentene copolymers, ethylene-1-hexene copolymers, ethylene-1-octene copolymers, propylene-1-butene copolymers, propylene-1-pentene copolymers, propylene-1-hexene copolymers, propylene-1-octene copolymers, etc. Among these, ethylene-propylene copolymers, ethylene-1-butene copolymers, and ethylene-1-octene copolymers are preferred.

[0042] Moreover, examples of styrene-based elastomers (that is, styrene-based thermoplastic elastomers having a styrene skeleton) include block copolymers of aromatic vinyl compounds and conjugated diene compounds, and hydrogenated products thereof. Examples of the aromatic vinyl compound include styrene, alkylstyrenes such as α-methylstyrene, p-methylstyrene, and p-tert-butylstyrene; p-methoxystyrene, and vinylnaphthalene. Examples of the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene, methylpentadiene, phenylbutadiene, 3,4-dimethyl-1,3-hexadiene, and 4,5-diethyl-1,3-octadiene.

[0043] Specific examples of styrene-based elastomers include styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene / butylene-styrene copolymer (SEBS), and styrene-ethylene / propylene-styrene copolymer (SEPS).

[0044] Examples of acid anhydrides for acid modification include maleic anhydride, phthalic anhydride, itaconic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, butenylsuccinic anhydride, etc. Among these, maleic anhydride, phthalic anhydride and itaconic anhydride are preferred. Examples of the carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid.

[0045] As the compatibilizer in the composite resin, among the various modified elastomers mentioned above, an acid anhydride modified elastomer is preferred, in particular a maleic anhydride modified elastomer, and further an acid modified product of an α-olefin copolymer containing a structural unit derived from an α-olefin having 3 to 8 carbon atoms is preferred. Specifically, an olefin thermoplastic elastomer having a skeleton of a copolymer of ethylene or propylene and an α-olefin having 3 to 8 carbon atoms is preferred, and more specifically, an elastomer modified with maleic anhydride, such as a maleic anhydride modified ethylene-propylene copolymer, a maleic anhydride modified ethylene-1-butene copolymer, a maleic anhydride modified ethylene-1-hexene copolymer, and a maleic anhydride modified ethylene-1-octene copolymer, is preferred. Specifically, an α-olefin copolymer "Tafmer series" (trade name) manufactured by Mitsui Chemicals Inc. or an "AMPLIFY series" (trade name) manufactured by Dow Chemical Company, etc. can be used.

[0046] The molecular weight of the modified elastomer is not particularly limited, but may be, for example, 10,000 or more and 500,000 or less, preferably 20,000 or more and 500,000 or less, and more preferably 30,000 or more and 300,000 or less. The molecular weight of the modified elastomer is a weight average molecular weight calculated in terms of polystyrene by gel permeation chromatography (GPC).

[0047] In addition to the thermoplastic resin described above, the resin layer 11 may contain other components as necessary. Examples of other components include various additives. For example, nucleating agents, antioxidants, heat stabilizers, weathering agents, light stabilizers, plasticizers, UV absorbers, antistatic agents, flame retardants, slip agents, antiblocking agents, antifogging agents, lubricants, pigments, dyes, dispersants, copper inhibitors, neutralizing agents, bubble inhibitors, weld strength improvers, natural oils, synthetic oils, waxes, etc. These may be used alone or in combination of two or more.

[0048] Examples of nucleating agents and reinforcing fillers include silicates such as talc, silica, clay, montmorillonite, and kaolin; carbonates such as calcium carbonate, lithium carbonate, and magnesium carbonate; metal oxides such as alumina, titanium oxide, and zinc oxide; metals such as aluminum, iron, silver, and copper; hydroxides such as aluminum hydroxide and magnesium hydroxide; sulfides such as barium sulfate; carbides such as charcoal and bamboo charcoal; titanides such as potassium titanate and barium titanate; celluloses such as cellulose microfibrils and cellulose acetate; and carbons such as fullerene.

[0049] Examples of the antioxidant include phenol-based compounds, organic phosphite-based compounds, and thioether-based compounds. Examples of the heat stabilizer include hindered amine compounds. Examples of the ultraviolet absorbing agent include benzophenone-based compounds, benzotriazole-based compounds, and benzoate-based compounds. The antistatic agent includes nonionic compounds, cationic compounds, anionic compounds, and the like. Examples of flame retardants include halogen-based compounds, phosphorus-based compounds (nitrogen-containing phosphate compounds, phosphoric esters, etc.), nitrogen-based compounds (guanidine, triazine, melamine, derivatives thereof, etc.), inorganic compounds (metal hydroxides, etc.), boron-based compounds, silicone-based compounds, sulfur-based compounds, and red phosphorus-based compounds. Examples of the flame retardant aid include antimony compounds, zinc compounds, bismuth compounds, magnesium hydroxide, and clay silicates.

[0050] The above-mentioned "laminated structure" is a structure in which the fiber assembly layer 12 and the resin layer 11 are alternately positioned. This laminated structure is formed by alternately laminating a continuous fiber sheet-like material 12' that becomes the fiber assembly layer 12 and a resin sheet 11' that becomes the thermoplastic resin layer 11 during the production of the fiber reinforced resin material 1. More specifically, for example, the laminate 1' of these alternately laminated sheets is heated and pressurized in the lamination direction to compress the laminate 1' and integrate the sheets together, thereby obtaining the fiber reinforced resin material 1. By such an operation, the thermoplastic resin and the fiber assembly layer 12 are firmly integrated, and the fiber reinforced resin material 1 that is integrated as a whole into a single layer can be obtained.

[0051] That is, for example, when the fiber assembly layer 12 does not contain a binder resin, the above-mentioned operation causes the resin layer 11 to be impregnated into the fiber assembly layer 12. Then, when the resin layer 11 is impregnated into the fiber assembly layer 12, the fiber reinforced resin material 1 has a laminated structure in which the fiber assembly layer 12 impregnated with the thermoplastic resin and the resin layer 11 made of the thermoplastic resin that has not been impregnated into the fiber assembly layer 12 and remains between the two fiber assembly layers 12 are alternately positioned.

[0052] On the other hand, when the fiber assembly layer 12 contains a binder resin, the resin layer is less impregnated into the fiber assembly layer 12 or is not impregnated at all. That is, when the above-mentioned operation is performed, the resin layer 11 is not impregnated or is lightly impregnated into the fiber assembly layer 12. As a result, a laminated structure is formed in which fiber assembly layers 12 lightly impregnated or not impregnated with the thermoplastic resin and resin layers 11 made of the thermoplastic resin that are not impregnated into the fiber assembly layers 12 and remain between the two fiber assembly layers are alternately positioned.

[0053] The thickness of each layer in the fiber reinforced resin material is as described above. The number of layers in the laminate structure is not limited, but may be, for example, 2 to 100,000 layers, 3 to 10,000 layers, 4 to 1,000 layers, or 5 to 100 layers. The fiber reinforced resin material may be composed of only the laminated structure described above, or may include a non-laminated structure. An example of the non-laminated structure is a portion composed of only a thermoplastic resin having a thickness 10 times or more the thickness of the resin layer. However, it is considered that the fiber reinforced resin material can exhibit better mechanical properties by being composed of only a laminated structure.

[0054] Moreover, in this fiber reinforced resin material, one side 1b has a higher elongation than the other side 1a. The reason why the elongation of one side 1b and the other side 1a differs in this way is because the fiber reinforced resin material 1 has a laminated structure. In other words, because it has a laminated structure, it is possible to give each layer a difference in composition, and as a result, it is possible to make the elongation of one side 1b and the other side 1a different. In the laminated structure, a layer region with high elongation is soft and has a relatively small maximum strength. Conversely, a layer region with low elongation is hard and has a relatively large maximum strength. For this reason, if a layer region with relatively high elongation is arranged on one side 1b and a layer region with relatively low elongation is arranged on the other side 1a, the one side 1b has a higher elongation than the other side 1a, and the mechanical property that the stress gradually decreases after reaching the maximum stress can be imparted. In other words, it is considered that toughness can be imparted to the fiber reinforced resin material 1.

[0055] In addition, the mechanical property that the stress gradually decreases after reaching the maximum stress is particularly excellent when the fiber reinforced resin material 1 has a gradient property that the one side 1b has a higher elongation than the other side 1a. The gradient means that the elongation is roughly arranged from "large to small" from the one side 1b to the other side 1a. More specifically, it may be "large to large to small", "large to small to small", "large to large to small to small", "large to large to large to small", "large to small to small to small", etc., and may further be "large to medium to small", "large to medium to small to small", "large to large to medium to small", "large to medium to small to small", "large to medium to small to small", etc. In any case, it is sufficient that the elongation gradually decreases from the one side 1a to the other side 1b.

[0056] In the fiber reinforced resin material 1, for example, when the elongation is changed depending on the type of thermoplastic resin constituting the resin layer 11, since the fiber assembly layer 12 and the resin layer 11 are alternately positioned, for example, when the elongation is measured for each layer from the one side 1b to the other side 1a, the elongation may be arranged as "small (fiber assembly layer) → large (resin layer) → small (fiber assembly layer) → medium (resin layer) → small (fiber assembly layer) → ..." etc. This is because the fiber assembly layer 12 has a lower elongation than the resin layer 11, but even in such an arrangement, the elongation of the resin layer 11, which is the main change, changes and decreases, so it can be said to be inclined.

[0057] In this way, in the fiber reinforced resin material 1, the one side 1b has a higher elongation than the other side 1a, in other words, the layer area with high elongation is arranged on the one side 1b and the layer area with low elongation is arranged on the other side 1a. Any configuration may be used, and for example, it may be formed as shown in the following (1) and (2). It may be formed in a configuration other than these (1) and (2), and the configuration for making the elongation different may be used alone or in combination of two or more types. (1) By having the thermoplastic resin layer 11 located on one side 1b and the thermoplastic resin layer 11 located on the other side 1a be different, the elongation of the one side 1a and the other side 1b can be made different (see FIG. 1a). (2) By making the fiber content of one side 1b different from the fiber content of the other side 1a, it is possible to make the elongation of one side 1b different from that of the other side 1a (see FIG. 1b).

[0058] Of the above, (1) by using a configuration in which the thermoplastic resin layer 11 located on one side 1b and the thermoplastic resin layer 1a located on the other side 1a are different, in order to make the elongation of one side 1b greater than that of the other side 1a, this can be achieved by arranging a thermoplastic resin with a relatively high elongation on one side 1b and a thermoplastic resin with a relatively low elongation on the other side 1a. More specifically, this can be achieved by using a composite resin of polyamide and polyolefin (which has higher elongation than polyamide) as the thermoplastic resin located on one side 1b, and using polyamide (which has higher strength than the composite resin) as the thermoplastic resin located on the other side 1a, out of the thermoplastic resins mentioned above. In addition, in this combination, since the composite resin contains polyamide, it can exhibit excellent affinity with polyamide. Therefore, even if these two types of thermoplastic resins are used, it is considered that peeling at the boundary area where the two are in contact can be suppressed. In addition, when polyamide particles are selected as the resin particles 122 attached to the continuous fibers 121, the affinity between the continuous fibers 121 and the composite resin can be improved, and the affinity between the continuous fibers 121 and the polyamide can be improved.

[0059] That is, with the above-mentioned configuration, the fiber assembly layer 12 and the resin layer 11 (the resin layer using the composite resin and the resin layer using the polyamide) can be firmly bonded, and the resin layer 11 using the composite resin and the resin layer 11 using the polyamide can also be firmly bonded, improving the integrity of the obtained fiber reinforced resin material 1. As a result, although the material is made of a plurality of different materials, it can function as an integrated material as a whole. Furthermore, since the one surface side 1b has a higher elongation than the other surface side 1a, it can exhibit excellent toughness.

[0060] Among the above, (2) using the configuration in which the fiber content of one side 1b and the fiber content of the other side 1a are different, in order to make the elongation of one side 1b greater than the elongation of the other side 1a, this can be achieved by arranging a fiber assembly layer 12 with a relatively low fiber content on one side 1b and arranging a fiber assembly layer 12 with a relatively high fiber content on the other side 1a. In such a fiber assembly layer with a low fiber content, the amount of continuous fibers contained in the thermoplastic resin is relatively small (density is low), so the properties of the thermoplastic resin are more strongly expressed. That is, the small amount of continuous fibers results in a fiber assembly layer with high elongation. On the other hand, in such a fiber assembly layer with a high fiber content, the amount of continuous fibers contained in the thermoplastic resin is relatively large (density is high), so the properties of the thermoplastic resin are less easily expressed. That is, the large amount of continuous fibers results in a fiber assembly layer with low elongation.

[0061] In the case of the above-mentioned configuration (2), the thermoplastic resin constituting the resin layer 11 is not limited. For example, the thermoplastic resin constituting the resin particles 122 attached to the continuous fibers 121 may be polyolefin, and the thermoplastic resin constituting the resin layer 11 may be polyolefin, so that the affinity between the two may be improved. In addition, the thermoplastic resin constituting the resin particles 122 attached to the continuous fibers 121 may be polyamide, and the thermoplastic resin constituting the resin layer 11 may be polyamide, so that the affinity between the two may be improved. Furthermore, the thermoplastic resin constituting the resin particles 122 attached to the continuous fibers 121 may be polyamide, and the thermoplastic resin constituting the resin layer 11 may be a composite resin of polyamide and polyolefin, so that the affinity between the two may be improved. The above-mentioned configurations can firmly bond the fiber assembly layer 12 and the resin layer 11, improving the integrity of the fiber reinforced resin material 1 obtained. This allows the material to function as a single material overall, even though it is made of multiple different materials. Furthermore, the one surface side 1b has a higher elongation than the other surface side 1a, allowing the material to exhibit excellent toughness.

[0062] In this fiber reinforced resin material, the fact that one side 1b has a higher elongation than the other side 1a is determined by dividing the fiber reinforced resin material 1 into two layers at the center of its thickness and measuring the breaking elongation of the one side layer and the other side layer at the same thickness. The breaking elongation is measured using an autograph by making the thickness and length of test pieces for the one side layer and the other side layer the same and conducting a tensile test at the same tensile speed, and measuring the elongation at the breaking point of the test piece.

[0063] Furthermore, for example, in the case of forming a fiber reinforced resin material having a physical property gradient by the above configuration (1), and in the case of using two types of thermoplastic resin, a composite resin of polyamide and polyolefin and a polyamide, for the resin layer 11, it is preferable that the number of interfaces between the resin layer using the composite resin and the resin layer using the polyamide is as small as possible. From this viewpoint, it is possible to provide a fiber reinforced resin material 1 having a two-layer structure in which two laminated parts 21, 22 are integrated, the laminated part 21 being formed by alternately laminating the resin layer 11 using the composite resin and the fiber assembly layer 12, and the laminated part 22 being alternately laminating the resin layer 11 using the polyamide and the fiber assembly layer 12. In such a fiber reinforced resin material 1, it is possible to realize a gradient in elongation while making the one side 1b higher in elongation than the other side 1a. In addition, it is possible to reduce the interface where different thermoplastic resins contact each other to essentially one interface. Therefore, it is possible to obtain particularly excellent mechanical properties. Specifically, it is possible to achieve a remarkably high bending stress and bending modulus of elasticity. Furthermore, it is possible to achieve a remarkably high bending stress, bending modulus of elasticity, and breaking strain.

[0064] In the two-layer fiber-reinforced resin material 1 in which the above-described two laminated portions 21 and 22 are integrated, the laminated portion 21 on one surface side 1b has a higher elongation than the laminated portion 22 on the other surface side 1a. These two laminated portions 21 and 22 may have the same thickness as each other or may have different thicknesses, but when they are different, higher bending stress can be realized. Furthermore, when the thickness of the laminated portion 21 on one surface side 1b is thicker than the thickness of the laminated portion 22 on the other surface side 1a, higher bending stress can be realized. More specifically, when the thickness of the laminated portion 21 on one surface side 1b is D1 (mm) and the thickness of the laminated portion 22 on the other surface side 1a is D2 (mm), excellent bending stress can be realized in the range of 0.5 < D2 / D1 < 1.0. This thickness ratio is more preferably 0.55 ≦ D2 / D1 ≦ 0.95, still more preferably 0.60 ≦ D2 / D1 ≦ 0.90, and even more preferably 0.65 ≦ D2 / D1 ≦ 0.85.

[0065] In addition, this fiber-reinforced resin material may or may not have other layers other than the fiber assembly layer 12, the resin layer 11, and the laminated structure. Examples of the other layers include a design layer, a bonding layer (a layer used for bonding with other materials), etc. These may be used alone or in combination of two or more.

[0066] The usage mode of this fiber-reinforced resin material 1 is not limited. For example, either one of the one surface side 1b (the side with relatively high elongation) and the other surface side 1a (the side with relatively low elongation) may be used as the impact input side. Among these, by using the other surface side 1a (the side with relatively low elongation) as the impact input side, significantly higher mechanical properties can be exhibited compared to the case of using the one surface side 1b (the side with relatively high elongation) as the impact input side. In particular, significantly high toughness can be exhibited. Specifically, with respect to the bending stress when the one surface side 1b (the side with relatively high elongation) is used as the impact input side, it is possible to improve the bending stress by 150% or more (more preferably 175% or more and 300% or less, still more preferably 200% or more and 260% or less) while maintaining the flexural modulus when the other surface side 1a (the side with relatively low elongation) is used as the impact input side.

[0067] Furthermore, the shape and size of the fiber reinforced resin material are not limited, and it can be made into any appropriate shape and size as required. For example, as shown in the examples described later, in the present fiber reinforced resin material, carbon fiber is selected as the continuous fiber 121, polyamide is selected as the resin particles 122, the above-mentioned composite resin and polyamide (particularly polyamide 6) are selected as the thermoplastic resin constituting the resin layer 11, and six layers of resin sheets (211) having a thickness of 10 to 250 μm and made of the composite resin, six layers of resin sheets (221) having a thickness of 50 to 150 μm and made of polyamide, and sheet-like objects 212 and 22 made of the continuous fiber 121 which is carbon fiber are used. When fiber reinforced resin material 1 having a laminated structure with a carbon fiber content of 20 to 60 volume % is obtained using 2, a fiber reinforced resin material can be obtained having a bending stress of 300 MPa or more (further, 350 MPa or more and 650 MPa or less, further 450 MPa or more and 600 MPa or less), a bending modulus of elasticity of 30 GPa or more (further, 35 GPa or more and 65 GPa or less, further 40 GPa or more and 55 GPa or less), and a fracture strain of 3 mm% or more (further, 3.5 mm% or more and 6.0 mm% or less, further 3.8 mm% or more and 5.7 mm% or less).

[0068] As the composite resin, (1) a composite resin of a melt-kneaded mixture of plant-derived PA and a compatibilizer (particularly an acid-modified olefin-based elastomer) and a polyolefin, which has a phase structure with PO as the parent phase, can be selected. In this composite resin, when the total of the plant-derived PA, PO, and compatibilizer is taken as 100 mass%, the plant-derived PA can be used at 10 mass% to 40 mass% (or even 15 mass% to 35 mass%), the PO can be used at 40 mass% to 75 mass% (or even 45 mass% to 70 mass%), and the compatibilizer can be used at 5 mass% to 35 mass% (or even 10 mass% to 30 mass%). Also, (2) a composite resin of a melt-kneaded mixture of PA6 and a compatibilizer (particularly an acid-modified olefin-based elastomer) and a polyolefin having a number-average molecular weight of 350,000 or more (even more, 450,000 or more) can be selected. In this composite resin, when the total of PA6, PO, and the compatibilizer is taken as 100 mass%, PA6 can be used at 15 mass% to 65 mass% (even more, 35 mass% to 55 mass%), PO can be used at 15 mass% to 65 mass% (even more, 20 mass% to 45 mass%), and the compatibilizer can be used at 5 mass% to 35 mass% (even more, 10 mass% to 30 mass%). Furthermore, (3) a composite resin of a melt-kneaded mixture of PA and a compatibilizer (particularly an acid-modified olefin elastomer) and a polyolefin, which has a bicontinuous phase structure in which both a phase with PA as the parent phase and a phase with PO as the parent phase exist, can be selected. In this composite resin, when the total of PA, PO, and the compatibilizer is taken as 100 mass%, PA can be used at 15 mass% to 70 mass% (or even 35 mass% to 65 mass%), PO can be used at 15 mass% to 65 mass% (or even 20 mass% to 50 mass%), and the compatibilizer can be used at 5 mass% to 35 mass% (or even 7 mass% to 30 mass%).

[0069] [2] Manufacturing method for fiber-reinforced resin materials The above-mentioned fiber reinforced resin material may be produced by any method, but can be produced by a method including a lamination step and a heat pressing step. Among these, the lamination step is a step of laminating a sheet-like material 12' of continuous fibers 121 that will become the fiber assembly layer 12 and a resin sheet 11' that will become the thermoplastic resin layer 11 so as to obtain a laminated structure. The hot pressing step is a step of heating and compressing the laminate 1' obtained through the lamination step in the lamination direction (see FIG. 3).

[0070] The above-mentioned "sheet-like material (12')" is a sheet-like material that will become the fiber assembly layer 12, and is formed by assembling continuous fibers 121 into a sheet shape. The continuous fibers 121 are as described above, and are not substantially changed before and after becoming the fiber-reinforced resin material 1. In the sheet-like material 12', the continuous fibers 121 may be assembled in any manner. That is, for example, the continuous fibers 121 may be assembled by being drawn together, may be woven and assembled like a woven fabric, may be knitted and assembled like a knitted fabric, or may be assembled without being woven like a nonwoven fabric. In addition, the sheet-like material may be composed of only one continuous fiber layer in which the continuous fibers are arranged in layers, or may be composed of two or more continuous fiber layers. The above-mentioned "resin sheet (11')" is a sheet-like material containing a thermoplastic resin, which is the resin component of the thermoplastic resin layer 11. The thermoplastic resin constituting this resin sheet 11' is as described above, and is not substantially changed before and after it is made into a fiber-reinforced resin material.

[0071] In the lamination step, the sheet-like material 12' and the resin sheet 11' may be laminated so as to obtain the desired laminate structure. However, during this lamination, the lamination may be performed so that the desired laminate structure is obtained by one heat-pressing step, but it can also be performed so that the desired laminate structure is obtained through two or more heat-pressing steps. That is, for example, a second laminate 22' having a laminate structure on one side 1b and a first laminate 21' having a laminate structure on the other side 1a are formed, and each of these is separately heated and compressed to obtain the second laminate structure 22' and the first laminate structure 21', and these are further laminated, and the obtained laminate is heated and compressed to obtain the desired fiber-reinforced resin material 1. That is, the fiber-reinforced resin material 1 can be obtained by finally integrating the laminates while dividing and laminating them in this way. Furthermore, when laminating the sheets, an adhesive or the like for bonding the sheets together may or may not be used so that the sheets are not separated from each other before the heat and pressure step.

[0072] In addition, the heating temperature and pressure applied in the heat pressing process are not limited and can be set to an appropriate range depending on the type of thermoplastic resin used. For example, when polyamide is selected as the resin particles 122 and the above-mentioned composite resin and polyamide are selected as the thermoplastic resin constituting the resin layer 11, the heating temperature can be 140°C or higher and 270°C or lower, 160°C or higher and 260°C or lower, or 180°C or higher and 250°C or lower. In addition, the pressure applied can be more than 0 MPa and 9.81 MPa or lower, more than 0 MPa and 9.0 MPa or lower, or more than 0 MPa and 7.0 MPa or lower. Furthermore, when multiple heat and pressure steps are performed to obtain one sheet of fiber reinforced resin material 1, the heating temperature and pressure in each step may be the same or different.

[0073] [3] Fiber-reinforced resin structure The fiber-reinforced resin structure of the present invention is made of the fiber-reinforced resin material described above. This fiber-reinforced resin structure can be called a fiber-reinforced resin molded body. The uses of the fiber-reinforced resin structure are not particularly limited, and it can be used, for example, as exterior materials, interior materials, structural materials (body shells, car bodies, aircraft fuselages), shock absorbing materials, etc. for automobiles, railroad cars, ships, airplanes, etc. Among these, examples of automotive products include exterior materials for automobiles, interior materials for automobiles, structural materials for automobiles, shock absorbing materials for automobiles, parts in engine rooms, etc.

[0074] Specific examples include bumpers, spoilers, cowlings, front grilles, garnishes, bonnets, trunk lids, cowl louvers, fender panels, rocker moldings, door panels, roof panels, instrument panels, center clusters, door trims, quarter trims, roof linings, pillar garnishes, deck trims, tonneau boards, package trays, dashboards, console boxes, kicking plates, switch bases, seat backboards, seat frames, armrests, sun visors, intake manifolds, engine head covers, engine under covers, oil filter housings, housings for automotive electronic components (ECUs, TV monitors, etc.), energy absorbers such as air filter boxes and rush boxes, and body shell components such as front end modules.

[0075] Further examples include interior materials, exterior materials, and structural materials for buildings and furniture. That is, the material can be door covering materials, door structural materials, covering materials and structural materials for various furniture (desks, chairs, shelves, chests, etc.), and even unit baths and septic tanks. In addition, the material can be used as packaging materials, containers (trays, etc.), protective materials, partition materials, etc. The material can also be used as molded articles such as housings and structures for home appliances (flat-screen TVs, refrigerators, washing machines, vacuum cleaners, mobile phones, portable game consoles, notebook computers, etc.). EXAMPLES

[0076] The present invention will now be described in detail with reference to examples. [1] Materials used (1-1) Sheet-like material W PA6 (PA6 particles) Carbon fibers with PA6 particles attached thereto were used as the continuous fibers 121. Toho Tenax Co., Ltd.'s product name "HTS40" (24K) was used as the base carbon fiber. After removing the sizing material from the surface of this base carbon fiber, it was immersed in the colloidal liquid shown below and electrophoresed at 30 V for 30 seconds to obtain a sheet-like material W of continuous fibers 121 with PA6 particles 122 attached to about 30 to 100 area % of the base carbon fiber surface. PA6 (12') was obtained. Colloidal solution: A liquid containing 750 mg of PA6 particles (average particle size 12 μm), 75 g of water, 400 mg of surfactant (sodium dodecyl sulfate, SDS), and 50 mg of potassium chloride.

[0077] (1-2) Sheet-like material W PMMA (PMMA particles) Carbon fibers with PMMA particles attached were used as the continuous fibers 121. Toho Tenax Co., Ltd.'s product name "HTS40" (24K) was used as the base carbon fiber. After removing the sizing material from the surface of this base carbon fiber, it was immersed in the colloidal liquid shown below and electrophoresed at 30 V for 30 seconds to obtain a sheet-like material W of continuous fibers 121 with PMMA particles 122 attached to about 30 to 100 area % of the base carbon fiber surface. PMMA (12') was obtained. Colloidal solution: A liquid containing 750 mg of PMMA particles (average particle size 0.25 μm), 75 g of water, 400 mg of surfactant (sodium dodecyl sulfate, SDS), and 50 mg of potassium chloride.

[0078] (1-3) Sheet-like material W NON (No resin particles) Carbon fibers without resin particles attached were used as the continuous fibers. Toho Tenax Co., Ltd.'s product name "HTS40" (24K) was used as the base carbon fiber. These carbon fibers were aligned and arranged to form a sheet-like material W. NON (12') was used.

[0079] (1-4) Resin sheet using PA6 Resin Sheet S PA6 : A sheet (11') made by molding PA6 (manufactured by Toray Industries, Inc., product name "CM1001") pellets to a thickness of 70 to 110 μm by heat pressing.

[0080] (1-5) Resin sheet using composite material C1 Composite material C1: A composite material (manufactured by Toyota Boshoku Corporation) having a PP matrix composed of PP, PA11, and a compatibilizer. Specifically, a composite material obtained by melt-kneading polypropylene (homopolymer with weight average molecular weight of 320,000), PA11 (manufactured by Arkema, product name "Rilsan BMN O", weight average molecular weight of 18,000), and a compatibilizer (maleic anhydride modified ethylene-butene copolymer, manufactured by Mitsui Chemicals, Inc., product name "Tafmer MH7020") in a mass ratio of 55%:25%:20% (melt-kneaded mixture of PA11 and compatibilizer with PP). Resin sheet S1 C1 : A sheet (11') made of composite material C1 molded to a thickness of 50 μm. Resin sheet S2 C1 : A sheet (11') made of composite material C1 molded to a thickness of 160 μm. Resin sheet S3 C1 : A sheet (11') made of composite material C1 molded to a thickness of 200 μm.

[0081] (1-6) Resin sheet using composite material C2 Composite material C2: A composite material (manufactured by Toyota Boshoku Corporation) of PP, PA6, and a compatibilizer having both PP and PA parent phases (bicontinuous phases). Specifically, a composite material (melt-kneaded mixture of PA6 and compatibilizer with PP) melt-kneaded with polypropylene (homopolymer with weight-average molecular weight of 320,000), PA6 (weight-average molecular weight of 18,000), and a compatibilizer (maleic anhydride modified ethylene-butene copolymer, manufactured by Mitsui Chemicals, Inc., product name "Tafmer MH7020") in a mass ratio of 32.5%:42.5%:25% (melt-kneaded mixture of PA6 and compatibilizer with PP). Resin Sheet S C2 : A sheet (11') made of composite material C2 molded to a thickness of 160 μm.

[0082] (1-7) Resin sheet using composite material C3 Composite material C3: A composite material having a PA matrix of PP, PA6, and a compatibilizer (manufactured by Toyota Boshoku Corporation). Specifically, a composite material obtained by melt-kneading polypropylene (homopolymer with weight-average molecular weight of 520,000), PA6 (weight-average molecular weight of 18,000), and a compatibilizer (maleic anhydride-modified ethylene-butene copolymer, manufactured by Mitsui Chemicals, Inc., product name "Tafmer MH7020") in a mass ratio of 32.5%:42.5%:25% (melt-kneaded mixture of PA6 and compatibilizer with PP). Resin Sheet S C3 : A sheet (11') made of composite material C3 molded to a thickness of 160 μm.

[0083] (1-8) Resin sheet using TPU Thermoplastic polyurethane elastomer resin: Manufactured by Okura Industrial Co., Ltd., product name "Silkron ET80". Resin Sheet S TPU : A sheet (11') made of TPU molded to a thickness of 150 μm.

[0084] [2] Preparation of fiber-reinforced resin material (1-1) Fiber-reinforced resin material having laminate structure A As shown in Figs. 7(a) and 7(b), four resin sheets S were laminated together to obtain a laminate structure A (a laminate structure of a comparative example) shown in Fig. 7(c). PA6 , 8 resin sheets S2 c1 , 10 sheets of sheet-like material W PA6 After laminating the above, heating and pressurization were performed under conditions of a temperature of 230° C. and a pressure of 0.3 to 5.0 MPa to obtain a fiber reinforced resin material having the laminate structure A of Experimental Examples 1 and 2 (see FIG. 7).

[0085] (1-2) Fiber-reinforced resin material having laminate structure B As shown in Figs. 8(a) to 8(b), four resin sheets S were laminated together to obtain a laminate structure B (a laminate structure of a comparative example) shown in Fig. 8(c). PA6 , 8 resin sheets S2 c1 , 10 sheets of sheet-like material W PA6 After laminating the above, heating and pressurization were performed under conditions of a temperature of 230° C. and a pressure of 0.3 to 5.0 MPa to obtain fiber reinforced resin materials having the laminate structure B of Experimental Examples 3 and 4 (see FIG. 8).

[0086] (1-3) Fiber-reinforced resin material having laminated structure C As shown in Figs. 9(a) and 9(b), four resin sheets S were laminated together to obtain a laminate structure C (a laminate structure of a comparative example) shown in Fig. 9(c). PA6 , 8 resin sheets S2 c1 , 10 sheets of sheet-like material W PA6 After laminating, heating and pressurization were performed under conditions of a temperature of 230° C. and a pressure of 0.3 to 5.0 MPa to obtain fiber reinforced resin materials having the laminated structures C of Experimental Examples 5 to 8 (see FIG. 9).

[0087] (1-4) Fiber-reinforced resin material having laminated structure D As shown in Figs. 10(a) and 10(b), four resin sheets S were laminated together to obtain a laminate structure D (a laminate structure of a comparative example) shown in Fig. 10(c). PA6 , 8 resin sheets S2 c1 , 10 sheets of sheet-like material W PA6 After laminating the above, heating and pressurization were performed under conditions of a temperature of 230° C. and a pressure of 0.3 to 5.0 MPa to obtain fiber reinforced resin materials having a laminate structure D of Experimental Examples 9 and 10 (see FIG. 10).

[0088] (1-5) Fiber-reinforced resin material having laminated structure E Four resin sheets S are stacked together to form the laminated structure E shown in Fig. 6(e). PA6 , 8 resin sheets S2 c1 , 10 sheets of sheet-like material W PA6 After laminating, heating and pressurization were performed under conditions of a temperature of 230° C. and a pressure of 0.3 to 5.0 MPa to obtain a fiber reinforced resin material having the laminate structure E (laminate structure of the example) of Experimental Examples 11 and 12 (see FIG. 6e). Six resin sheets S are stacked together to form the laminated structure E shown in Fig. 5(b). PA6 , 6 resin sheets S2 c1 , 10 sheets of sheet-like material W PA6 After laminating, heating and pressurization were performed under conditions of a temperature of 230° C. and a pressure of 0.3 to 5.0 MPa to obtain fiber reinforced resin materials having laminate structure E (laminate structure of the example) of Experimental Examples 13 and 14 (see FIGS. 4 and 5). In practice, as shown in FIG. 4(a), six resin sheets S PA6 (211) and five sheets of W PA6 The first laminate obtained by alternately laminating the resin sheets S2 and S3 is heated and compressed to obtain a first laminate structure 21'. Further, as shown in FIG. 4(b), six resin sheets S2 are laminated. c2 (221) and five sheets of W PA6 (222) are alternately laminated to obtain a second laminate 22'. Then, as shown in Fig. 5(a), the first laminate 21' and the second laminate 22' are laminated and further heated and compressed to obtain a fiber reinforced resin material 1 having a laminate structure E. The fiber reinforced resin material 1 having this laminate structure E can be simplified as shown in Fig. 5(b) as a fiber reinforced resin material 1 in which the second laminate 22 is located on one surface 1b and the first laminate 21 is located on the other surface 1a.

[0089] (1-6) Fiber-reinforced resin material having laminated structure F Six resin sheets S are stacked together to form a laminated structure F, which is the upside-down structure of Figure 5(b). PA6 , 6 resin sheets S2 c1 , 10 sheets of sheet-like material W PA6 After laminating, heating and pressurization were performed under conditions of a temperature of 230° C. and a pressure of 0.3 to 5.0 MPa to obtain fiber reinforced resin materials having laminate structure F (laminate structure of the embodiment) of Experimental Examples 15 and 16 (see FIGS. 4 and 5).

[0090] [Table 1]

[0091] (1-7) Fiber-reinforced resin material having laminated structure E To obtain the laminated structure E shown in FIG. 5(b), 1 to 6 resin sheets S shown in Table 2 were used. PA6 , 6 to 11 resin sheets S2 shown in Table 2 c1 , 10 sheets of sheet-like material W PA6After laminating the resin sheet S, heating and pressurization were performed under conditions of a temperature of 230° C. and a pressure of 0.3 to 5.0 MPa to obtain fiber-reinforced resin materials having the laminate structure E (laminate structure of the embodiment) of Experimental Examples 11 to 14 and Experimental Examples 19 to 26 (see Figs. 4, 5, and 6). PA6 6 sheets, resin sheet S2 C1 Six examples of each are shown below. In addition, 12 resin sheets S2 were prepared in the same manner. c1 and 10 sheets of sheet-like material W PA6 The fiber reinforced resin materials of Experimental Examples 17 to 18 (comparative laminated structures) were obtained using the above.

[0092] [Table 2]

[0093] (1-8) Fiber-reinforced resin material having laminated structure G After laminating each resin sheet and each sheet-like material shown in Table 3, heating and pressurization were performed under conditions of a temperature of 230°C and a pressure of 0.3 to 5.0 MPa to obtain fiber-reinforced resin materials having laminate structures G (comparative laminate structures) of Experimental Examples 29 to 50.

[0094] [Table 3]

[0095] (3) Flexural modulus In accordance with JIS K7074, a three-point bending test was performed on a test piece (width 12 mm, thickness 2.4 mm, length 100 mm) with a support distance of 80 mm and a bending speed of 5 mm / min. The bending stress, bending modulus, and fracture strain were measured and are shown in Tables 1 to 3.

[0096] The above examples are merely illustrative and are not to be construed as limiting the present invention. Although the present invention has been described with reference to exemplary embodiments, it is understood that the words used in describing and illustrating the present invention are descriptive and exemplary, rather than limiting. As detailed herein, changes may be made within the scope of the appended claims without departing from the scope or spirit of the present invention in its form. Although the present invention has been described herein with reference to specific structures, materials and examples, it is not intended that the present invention be limited to the disclosures set forth herein, but rather that the present invention extends to all functionally equivalent structures, methods and uses within the scope of the appended claims. [Explanation of symbols]

[0097] 1; fiber reinforced resin material; 1'; laminate to be the fiber reinforced resin material; 1a: Other side, 1b; One side, 11; thermoplastic resin layer, 11'; resin sheet, 12; fiber assembly layer; 12'; sheet-like material; 121; continuous fiber (base continuous fiber), 122; resin particles, 21, 22: laminated portion; 21', 22': laminated material to be laminated portion; 211; resin sheet, 212;Sheet-like material.

Claims

1. A fiber reinforced resin material having a laminated structure in which fiber assembly layers and thermoplastic resin layers are alternately positioned, The fiber assembly layer is an assembly of continuous fibers having thermoplastic resin particles attached to the surface thereof, The fiber reinforced resin material has a higher elongation on one side than on the other side, The thermoplastic resin layer located on the one surface side is different from the thermoplastic resin layer located on the other surface side, A fiber-reinforced resin material, characterized in that the thermoplastic resin constituting the thermoplastic resin layer located on the one side is a composite resin containing polyamide and polyolefin.

2. The fiber reinforced resin material according to claim 1 , wherein the fiber content on the one surface side is different from the fiber content on the other surface side.

3. The fiber-reinforced resin material according to claim 1 or 2, wherein the continuous fibers are carbon fibers.

4. The fiber-reinforced resin material according to claim 1 , wherein the thermoplastic resin constituting the thermoplastic resin particles contains polyamide.

5. A fiber reinforced resin material having a laminated structure in which fiber assembly layers and thermoplastic resin layers are alternately positioned, The fiber assembly layer is an assembly of continuous fibers having thermoplastic resin particles attached to the surface thereof, The fiber reinforced resin material has a higher elongation on one side than on the other side, A fiber-reinforced resin material, characterized in that the thermoplastic resin constituting the thermoplastic resin particles contains polyamide.

6. The fiber reinforced resin material according to claim 5 , wherein the thermoplastic resin layer located on the one surface side is different from the thermoplastic resin layer located on the other surface side.

7. 7. The fiber-reinforced resin material according to claim 5, wherein the thermoplastic resin constituting the thermoplastic resin layer located on the one side is a composite resin containing polyamide and polyolefin.

8. The fiber reinforced resin material according to claim 5 , wherein the fiber content on the one surface side is different from the fiber content on the other surface side.

9. 9. The fiber-reinforced resin material according to claim 5, wherein the continuous fibers are carbon fibers.

10. A fiber-reinforced resin structure comprising the fiber-reinforced resin material according to any one of claims 1 to 9.

11. A method for producing a fiber-reinforced resin material according to any one of claims 1 to 9, a lamination step of laminating the sheet-like material of the continuous fibers that will become the fiber assembly layer and a resin sheet that will become the thermoplastic resin layer so as to obtain the laminated structure; A method for producing a fiber-reinforced resin material, comprising: a hot-pressing step of hot-compressing the laminate obtained through the lamination step in a lamination direction.

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