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

Abstract

To provide a fiber-reinforced resin material further hard to crack, a production method therefor and a fiber-reinforced resin structure.SOLUTION: A fiber-reinforced resin material 1 comprises a first fiber-reinforced resin layer 11, a second fiber-reinforced resin layer 12 having higher ductility and lower elasticity than the first layer 11 and a third fiber-reinforced resin layer 13 having higher ductility and lower elasticity than the second layer 12. A fiber-reinforced resin structure in which the first, second and third layers are laminated to be integrated comprises the above fiber-reinforced resin material. The production method for the above material comprises a process of laminating a sheet-like material prepared by forming a continuous fiber W1 into a sheet-like matter, and a resin sheet prepared by the first, second or third thermoplastic resin so that the lamination structure in which the first, second and third layers are laminated in this order is obtained, and a process of heat-compressing the obtained laminate toward a lamination 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 comprises a first fiber reinforced resin layer, A second fiber reinforced resin layer having higher ductility and lower elasticity than the first fiber reinforced resin layer; A third fiber reinforced resin layer having higher ductility and lower elasticity than the second fiber reinforced resin layer, The first fiber reinforced resin layer, the second fiber reinforced resin layer, and the third fiber reinforced resin layer are laminated and integrated in this order. [2] In the fiber-reinforced resin material of the present invention, the first fiber-reinforced resin layer contains a first thermoplastic resin and continuous fibers, The second fiber reinforced resin layer includes a second thermoplastic resin and continuous fibers, The third fiber reinforced resin layer includes a third thermoplastic resin and continuous fibers, The first thermoplastic resin, the second thermoplastic resin, and the third thermoplastic resin may be three different thermoplastic resins. [3] In the fiber-reinforced resin material of the present invention, the first thermoplastic resin, the second thermoplastic resin and the third thermoplastic resin can be selected from thermoplastic resin A, thermoplastic resin B, and composite resins thereof, respectively. [4] In the fiber-reinforced resin material of the present invention, each of the continuous fibers has particles attached to its surface, The particles may be made of any one of the thermoplastic resin A, the thermoplastic resin B, and the composite resin. [5] In the fiber-reinforced resin material of the present invention, the first fiber-reinforced resin layer, the second fiber-reinforced resin layer, and the third fiber-reinforced resin layer may have different fiber contents. [6] 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. [7] The method for producing a fiber-reinforced resin material of the present invention includes a lamination step of laminating a sheet-like material obtained by forming the continuous fibers into a sheet and each resin sheet which is the first thermoplastic resin, the second thermoplastic resin, or the third thermoplastic resin, so as to obtain a laminated structure in which the first fiber-reinforced resin layer, the second fiber-reinforced resin layer, and the third fiber-reinforced resin layer are laminated in this order; 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 resistance to cracking compared to conventional fiber-reinforced resin materials and structures, and in particular can increase the amount of energy that can be absorbed before breaking. 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. In particular, it is possible to obtain a fiber-reinforced resin material and a fiber-reinforced resin structure that can absorb a large amount of energy before breaking. [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 an example of a fiber reinforced resin material. [Diagram 2] FIG. 2 is an explanatory diagram partially illustrating an example of a method for producing a fiber-reinforced resin material. [Diagram 3] FIG. 2 is an explanatory diagram partially illustrating an example of a method for producing a fiber-reinforced resin material. [Figure 4] FIG. 2 is an explanatory diagram partially illustrating an example of a method for producing a fiber-reinforced resin material. [Diagram 5] FIG. 2 is an explanatory diagram partially illustrating an example of a method for producing a fiber-reinforced resin material. [Figure 6] FIG. 2 is an explanatory diagram showing an example of a continuous fiber. [Figure 7] FIG. 11 is an explanatory diagram illustrating another example of a fiber reinforced resin material. [Figure 8] FIG. 11 is an explanatory diagram illustrating another example of a fiber reinforced resin material. [Figure 9] FIG. 11 is an explanatory diagram illustrating another example of a fiber reinforced resin material. [Figure 10] 10A to 10C are explanatory diagrams illustrating another example of a method for producing a fiber-reinforced resin material. [Figure 11] 1 is a multiple chart showing stress-strain curves for various fiber reinforced resin materials. [Figure 12] FIG. 2 is an explanatory view showing an enlarged view of the vicinity of the fracture site of the test piece in Experimental Example 1. 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 comprises a first fiber-reinforced resin layer (11), A second fiber reinforced resin layer (12) having higher ductility and lower elasticity than the first fiber reinforced resin layer (11); A third fiber reinforced resin layer (13) having higher ductility and lower elasticity than the second fiber reinforced resin layer (12), The first fiber reinforced resin layer (11), the second fiber reinforced resin layer (12), and the third fiber reinforced resin layer (13) are laminated and integrated in this order (see FIG. 1).

[0012] [1-1] Fiber-reinforced resin layer The above-mentioned first fiber reinforced resin layer 11 (hereinafter also simply referred to as the "first layer"), second fiber reinforced resin layer 12 (hereinafter also simply referred to as the "second layer"), and third fiber reinforced resin layer 13 (hereinafter also simply referred to as the "third layer") are all fiber reinforced resin layers 10 (see Figure 1). The fiber reinforced resin layer 10 is a layer containing reinforcing fibers W1 and a binder resin S1 that bonds the reinforcing fibers together (see a partial enlarged view of FIG. 1). The second layer 12 has higher ductility and lower elasticity than the first layer 11, and the third layer 13 has higher ductility and lower elasticity than the second layer 12. The difference between the first layer, the second layer, and the third layer is usually caused by differences in the content (content) of the reinforcing fiber W1 and the binder resin S1.

[0013] [1-2] Reinforced fiber The reinforcing fibers W1 (see Figs. 1 and 6) may be discontinuous fibers, continuous fibers, or a combination of both. In the present invention, it is preferable that the reinforcing fibers W1 are only continuous fibers or are mainly continuous fibers (50% by mass or more and less than 100% by mass of the entire fibers). By using the continuous fibers, the mechanical strength of the fiber-reinforced resin layer 10 can be improved.

[0014] The fiber length of the reinforcing fiber W1 is not limited, but can be, for example, 15 mm or more. A fiber length of 15 mm or more can increase the number of intersections between the reinforcing fibers, thereby increasing the strength of the fiber assembly described below. 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] That is, the reinforcing fibers W1 may be discontinuous fibers, continuous fibers, or a combination of these, but in the present invention, it is preferable that only continuous fibers or mainly continuous fibers (50% by mass or more to 100% by mass of the entire fibers) are used. By using continuous fibers, the mechanical strength of the fiber-reinforced resin layer 10 can be improved. Thus, non-continuous fibers can be fibers chopped to less than 15 mm (such as short fibers), whereas continuous fibers can be fibers chopped to 15 mm or more (such as long fibers), fibers chopped to 50 mm or more (such as long fibers), fibers chopped to 100 mm or more (such as long fibers), fibers chopped to 500 mm or more (such as long fibers), or even fibers that are not substantially chopped.

[0016] The material constituting the reinforcing fiber W1 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.)).

[0017] Furthermore, the reinforcing fibers W1 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.

[0018] Among the above, the fiber reinforced resin material can exhibit particularly excellent performance by using carbon fibers as the reinforcing fibers W1. 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. Furthermore, when carbon fibers are selected as the reinforcing fibers W1 and are bundled together for use, 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 be 1000 or more and 50000 or less, 1500 or more and 40000 or less, or 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 particles (thermoplastic resin particles) described later. 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.).

[0019] [1-3] Attached particles Reinforcement fiber W1 is fiber W 11 Particles W attached to the surface of 12(See FIG. 6). 12 In the case where the particle W has a diameter of 10 mm or less, the binder resin S1 can easily enter between the reinforcing fibers W1, thereby improving the mechanical strength of the fiber-reinforced resin material. 12 As the binder resin S1, particles W made of a material having affinity with the resin component constituting the binder resin S1 are 12 When the binder resin S1 is used, the adhesion between the reinforcing fiber W1 and the binder resin S1 can be strengthened, and the starting point of fracture between these different materials can be reduced. In particular, when the binder resin S1 is a thermoplastic resin, this effect can be obtained more significantly. That is, since a thermoplastic resin has superior elongation compared to a curable resin, it is considered that the use of a thermoplastic resin as the binder resin S1 can impart toughness to the fiber reinforced resin material. On the other hand, when a thermoplastic resin with excellent elongation is used as the binder resin S1, it may have a higher elongation than the reinforcing fiber W1, but when the above-mentioned particles W 12 By having this, the interfacial separation between the reinforcing fibers W1 and the binder resin S1 can be more effectively reduced, so that the high elongation property due to the use of a thermoplastic resin can be more fully utilized.

[0020] Particle W attached to reinforcing fiber W1 12 The material constituting the particles is not limited, but as described above, when the material is a thermoplastic resin together with the binder resin S1, excellent effects can be obtained. Therefore, it is preferable that the material constituting the particles is a thermoplastic resin together with the binder resin S1. As the thermoplastic resin, various thermoplastic resins exemplified as resins constituting the binder resin S1 described later can be used. Furthermore, the binder resin S1 and the particles W 12 From the viewpoint that it is preferable for the particles W to have a higher affinity with the material constituting the particles W 12It is preferable that the thermoplastic resin constituting the binder resin S1 is the same type of thermoplastic resin or contains the same type of thermoplastic resin as a component resin. Examples of the same type of thermoplastic resin include polyamides, polyolefins, and polyesters. Examples of the same type of resin as a component resin include a case where the binder resin S1 is a melt-kneaded mixture of polyolefins, polyamides, and a compatibilizer therefor, and the thermoplastic resin constituting the particles contains polyolefins and / or polyamides.

[0021] Particles W to reinforcing fiber W1 12 Any method may be used for the attachment of the particles W1, but for example, when the reinforcing fiber W1 is an electrically conductive fiber, particularly a carbon fiber, the disclosures of JP 2017-82060 A and WO 2017-150702 A can be used. That is, for example, the reinforcing fiber W1 is immersed in (1) a colloidal solution containing particles, a nonionic surfactant, an electrolyte, and water, or (2) a colloidal solution containing particles, a radical polymerization initiator, and water, and a voltage is applied with the reinforcing fiber W1 as a positive electrode or a negative electrode to perform electrophoresis, thereby attaching the particles W1 to the reinforcing fiber W1. 12 can be attached.

[0022] Particle W 12 The size of the powder 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 reinforcing fiber W1, the powder 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. And particle W 12 can be attached to, for example, 30 to 100% by area, or even 60 to 99% by area, of the surface of the reinforcing fiber. The average particle size of the particles can be measured by observation with a scanning electron microscope. More specifically, in a still image enlarged by a scanning electron microscope, the maximum diameters of any 20 particles attached to the reinforcing fiber W1 are measured, and the average value thereof can be regarded as the average particle size.

[0023] [1-4] Fiber assembly The state of the reinforcing fibers W1 in the fiber reinforced resin layer 10 is not limited, but they are usually included as an aggregate of fibers (fiber aggregate layer). When the reinforcing fibers W1 are discontinuous fibers, the fiber assembly may be a nonwoven fabric in which discontinuous fibers are deposited. Examples of the fiber assembly when the reinforcing fiber W1 is a continuous fiber include a fiber assembly in which continuous fibers are aligned, a fiber assembly in which tows of continuous fibers are aligned, a fiber assembly woven from continuous fibers (woven fabric using continuous fibers), a fiber assembly woven from tows of continuous fibers (woven fabric using tows), etc. These may be used alone or in combination of two or more.

[0024] In addition, even if the fiber assembly uses continuous fibers, the fiber assembly may contain discontinuous fibers in addition to the continuous 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 are taken as 100% by mass.

[0025] The fiber assembly may be used in a single layer, but may also be used in a multi-layer. When the fiber assembly is layered, the layer thickness 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 is not limited, but may be, for example, 0.1 g / m 2 More than 100000g / m 2 It can be as follows: The layer thickness of the fiber assembly can be measured by observation with a scanning electron microscope. More specifically, the thickness is measured at any 10 points in a still image of an enlarged cross section of the fiber-reinforced resin material in the lamination direction, and the average value of the measured thicknesses is regarded as the layer thickness.

[0026] [1-5] Binder resin The binder resin S1 is a resin (matrix resin) that bonds the reinforcing fibers together. The binder resin S1 may be a curable resin (curable by heat, energy rays, etc.), a thermoplastic resin, or a combination of these, with the thermoplastic resin being preferred. The binder resin S1 may be composed of only a resin component, but may also contain other components (non-resin components, etc.) such as a filler in addition to the resin component (in this case, it can be called a binder resin composition). The other components will be described later.

[0027] The type of thermoplastic resin is not limited, and examples thereof include polyamide, polyolefin, polyester, polycarbonate, acrylic resin, fluorine-containing thermoplastic resin, polyimide, polyamideimide, and further, resin alloys (composite resins) containing two or more of these thermoplastic resins. These may be used alone or in combination of two or more.

[0028] 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.

[0029] 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).

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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).

[0043] 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.

[0044] 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.

[0045] 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).

[0046] The binder resin S1 may contain other components as necessary in addition to the above-mentioned thermoplastic resin. Examples of other components include various additives. For example, nucleating agents, antioxidants, heat stabilizers, weathering agents, light stabilizers, plasticizers, ultraviolet absorbers, antistatic agents, flame retardants, slip agents, antiblocking agents, antifogging agents, lubricants, pigments, dyes, dispersants, copper damage 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.

[0047] 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.

[0048] 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.

[0049] [1-6] 1st, 2nd and 3rd layers The first layer 11, the second layer 12, and the third layer 13 have the following specific correlation: the second layer 12 has higher ductility and lower elasticity than the first layer 11, and the third layer 13 has higher ductility and lower elasticity than the second layer 12. Due to this correlation, the fiber reinforced resin material in which the first layer 11, the second layer 12, and the third layer 13 are laminated together in this order has superior crack resistance compared to a fiber reinforced resin material that does not have this configuration. In particular, the amount of energy that can be absorbed before breaking can be increased.

[0050] In particular, in the fiber reinforced resin material having the above configuration, when an impact is applied from the first layer side to the third layer side, a remarkably excellent resistance to cracking can be obtained. The reason for this can be considered, for example, as follows. In general, a fiber reinforced resin material has a trade-off in that the fracture strain becomes smaller as the strength (elastic modulus) increases. That is, since a high-strength fiber reinforced resin material is difficult to deform, even if an impact is applied, the strain remains small, and when the strength limit is reached, the fiber reinforced resin material itself will crack.

[0051] In contrast, the fiber reinforced resin material of the present invention has high strength and yet can have a large fracture strain. Therefore, when an impact is input, each fiber reinforced resin layer can withstand up to its individual strength, and when that limit is reached, each fiber reinforced resin layer is destroyed individually. Specifically, the first layer, which has the highest strength, is destroyed, but the other layers are not destroyed because they have higher ductility than the first layer. Therefore, the fiber reinforced resin material as a whole is not destroyed all at once and does not crack.

[0052] Furthermore, even if the first layer is broken, since it is laminated and integrated with other layers, interlaminar breakage with the second layer is suppressed, so the stress concentration point in the first layer moves, and multiple breakages occur in the first tank. On the other hand, the second to third layers have higher ductility than the first layer, so they function as toughness and can be distorted. For this reason, the entire fiber reinforced resin material does not break at once, and while fracture progresses in each layer, the breakage can progress gradually toward the third layer side, so it is thought that each layer can withstand an impact with a strain while the breakage progresses. That is, as a result, the fiber reinforced resin material can have a high fracture strain compared to the conventional material while being high in strength, and can be a material that suppresses the above-mentioned trade-off.

[0053] The above-mentioned correlation, that is, the second layer has higher ductility and lower elasticity than the first layer, and the third layer has higher ductility and lower elasticity than the second layer, may be formed in any manner, but may be formed by a difference in the binder resin S1 and / or a difference in the content (content) of the reinforcing fiber W1. Specifically, when the first layer 11 contains a first thermoplastic resin and continuous fibers, the second layer 12 contains a second thermoplastic resin and continuous fibers, and the third layer 13 contains a third thermoplastic resin and continuous fibers, the first thermoplastic resin, the second thermoplastic resin, and the third thermoplastic resin may be three different thermoplastic resins. That is, this can be achieved by selecting a thermoplastic resin having higher ductility (higher elongation) than the first thermoplastic resin (hereinafter simply referred to as "first resin") as the second thermoplastic resin (hereinafter simply referred to as "second resin"), and further selecting a thermoplastic resin having higher ductility (higher elongation) than the second resin as the third thermoplastic resin (hereinafter simply referred to as "third resin").

[0054] Furthermore, in this case, by using a thermoplastic resin selected from thermoplastic resin A, thermoplastic resin B, and a composite resin thereof as the first, second, and third resins, respectively, it is possible to maintain high bonding strength between the first, second, and third layers, thereby suppressing breakage between the layers and allowing active movement of the stress concentration point. In this case, for example, (1) a thermoplastic resin A can be used as the first resin, a composite resin can be used as the second resin, and a thermoplastic resin B can be used as the third resin. Furthermore, for example, (2) a thermoplastic resin A can be used as the first resin, a first composite resin can be used as the second resin, and a second composite resin can be used as the third resin. In this case, the first composite resin and the second composite resin can be resins having different blending ratios of the thermoplastic resins A and B. Furthermore, for example, (3) a first composite resin can be used as the first resin, a second composite resin can be used as the second resin, and a third composite resin can be used as the third resin. In this case, the first composite resin, the second composite resin, and the third composite resin can be resins having different blending ratios of thermoplastic resins A and B.

[0055] More specifically, polyamide can be selected as the thermoplastic resin A, and polyolefin can be selected as the thermoplastic resin B. As a result, the higher the proportion of polyamide, the lower the ductility and higher the elasticity of the fiber-reinforced resin layer can be formed. On the other hand, the higher the proportion of polyolefin, the higher the ductility and lower the elasticity of the fiber-reinforced resin layer can be formed. Therefore, by changing the compounding ratio of polyamide and polyolefin, three different fiber-reinforced resin layers having three different types of ductility and elasticity, each having affinity with the other, and excellent bonding strength can be formed. In addition, as described above, a compatibilizer can be used to improve the compatibility between the thermoplastic resin A and the thermoplastic resin B.

[0056] More specifically, when a plant-derived polyamide is selected as the thermoplastic resin A and a polyolefin (or polypropylene) is selected as the thermoplastic resin B, the composite resin may be a composite resin of a melt-kneaded mixture of a plant-derived polyamide and a compatibilizer (particularly an acid-modified olefin-based elastomer) and a polyolefin, which has a phase structure with the polyolefin as the parent phase. In this composite resin, when the total of the plant-derived polyamide, the polyolefin, and the compatibilizer is taken as 100% by mass, the plant-derived polyamide may be used at 10% by mass to 40% by mass (or at 15% by mass to 35% by mass), the polyolefin may be used at 40% by mass to 75% by mass (or at 45% by mass to 70% by mass), and the compatibilizer may be used at 5% by mass to 35% by mass (or at 10% by mass to 30% by mass).

[0057] When polyamide 6 is selected as the thermoplastic resin A and polyolefin (or polypropylene) is selected as the thermoplastic resin B, the composite resin may be a melt-kneaded mixture of polyamide 6 and a compatibilizer (particularly an acid-modified olefin-based elastomer) and a polyolefin having a number average molecular weight of 350,000 or more (or even 450,000 or more). In this composite resin, when the total of polyamide 6, polyolefin, and compatibilizer is taken as 100 mass%, polyamide 6 can be used at 15 mass% to 65 mass% (or even 35 mass% to 55 mass%), polyolefin can be used at 15 mass% to 65 mass% (or even 20 mass% to 45 mass%), and compatibilizer can be used at 5 mass% to 35 mass% (or even 10 mass% to 30 mass%).

[0058] Similarly, when polyamide (such as plant-derived polyamide or polyamide 6) is selected as thermoplastic resin A and polyolefin (even polypropylene) is selected as thermoplastic resin B, a composite resin having a bicontinuous phase structure in which both a polyamide-based phase and a polyolefin-based phase exist can be selected, which is a composite resin of a melt-kneaded mixture of polyamide and a compatibilizer (particularly an acid-modified olefin-based elastomer) and a polyolefin. In this composite resin, when the total of polyamide, polyolefin, and compatibilizer is 100 mass%, polyamide can be used at 15 mass% to 70 mass% (even 35 mass% to 65 mass%), polyolefin can be used at 15 mass% to 65 mass% (even 20 mass% to 50 mass%), and compatibilizer can be used at 5 mass% to 35 mass% (even 7 mass% to 30 mass%).

[0059] As described above, the reinforcing fiber W1 is attached to the surface of the particle W 12 If we have particle W 12 As the material constituting the first embodiment, it is preferable to select any one of thermoplastic resins from among thermoplastic resin A, thermoplastic resin B, and composite resin.

[0060] Specifically, (1) when a thermoplastic resin A is used as the first resin, a composite resin is used as the second resin, and a thermoplastic resin B is used as the third resin, the particles attached to the continuous fibers forming the first layer can be thermoplastic resin A or the composite resin. Similarly, the particles attached to the continuous fibers forming the second layer can be thermoplastic resin A, thermoplastic resin B, or the composite resin. Similarly, the particles attached to the continuous fibers forming the third layer can be thermoplastic resin B or the composite resin.

[0061] Also, (2) when a thermoplastic resin A is used as the first resin, a first composite resin is used as the second resin, and a second composite resin is used as the third resin, the particles attached to the continuous fibers forming the first layer can be thermoplastic resin A or a composite resin. Similarly, the particles attached to the continuous fibers forming the second layer can be thermoplastic resin A, thermoplastic resin B, or a composite resin. Similarly, the particles attached to the continuous fibers forming the third layer can be thermoplastic resin A, thermoplastic resin B, or a composite resin. Furthermore, (3) when different composite resins are used for all of the first resin to the third resin, the particles attached to the continuous fibers constituting each of the first layer to the third layer can be made of thermoplastic resin A, thermoplastic resin B, or a composite resin.

[0062] In addition, the correlation in which the second layer is more ductile and less elastic than the first layer, and the third layer is more ductile and less elastic than the second layer, can be formed by using the first layer, the second layer, and the third layer having different fiber contents of the reinforcing fiber W1. Specifically, the layer with the higher fiber content has lower ductility and higher elasticity than the layer with the lower fiber content. Therefore, by arranging the first layer, the second layer, and the third layer in the order of decreasing fiber content, it is possible to obtain the correlation in which the second layer is more ductile and less elastic than the first layer, and the third layer is more ductile and less elastic than the second layer.

[0063] Furthermore, by utilizing both the difference in the binder resin S1 and the difference in the content of the reinforcing fiber W1, a correlation may be obtained in which the second layer is more ductile and has lower elasticity than the first layer, and the third layer is more ductile and has lower elasticity than the second layer.

[0064] The first layer, the second layer, and the third layer may be laminated together in any manner, but usually, the first layer and the second layer are laminated together by bonding the binder resin contained in the first layer with the binder resin contained in the second layer. Similarly, the second layer and the third layer are laminated together by bonding the binder resin contained in the second layer with the binder resin contained in the third layer. As a result, the three layers are laminated together as a whole.

[0065] The thickness of each of the first, second and third fiber-reinforced resin layers is not limited, and the first, second and third layers may be the same thickness or different thicknesses. These layers 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-reinforced resin layer is not limited, and may be, for example, 0.1 g / m 2 More than 100000g / m 2 It can be as follows: The thickness of the fiber-reinforced resin layer can be measured by scanning electron microscope observation. More specifically, the thickness is measured at 10 arbitrary points in a still image of an enlarged cross section of the fiber-reinforced resin material in the lamination direction, and the average value of the measured thicknesses is regarded as the layer thickness.

[0066] In addition, each fiber reinforced resin layer may be formed in any manner, but as shown in the examples described later, a laminate in which a resin sheet serving as a binder resin is inserted between layers of a plurality of layers of a fiber assembly (or a laminate in which a plurality of layers of a fiber assembly is inserted between layers of a plurality of resin sheets serving as a binder resin) is heated and pressurized to impregnate the fiber assembly with the binder resin. In this case, when the entire amount of the binder resin constituting the resin sheet is impregnated into the fiber assembly, the fiber reinforced resin layer is one in which the reinforcing fibers W1 and the binder resin S1 are evenly present. On the other hand, even if the binder resin constituting the resin sheet is sufficiently impregnated into the fiber assembly, there may be an excess of the binder resin constituting the resin sheet. In this case, each fiber reinforced resin layer is a fiber reinforced resin layer in which a resin layer consisting of only the binder resin and a fibrous layer in which the binder resin is impregnated into the fiber assembly are alternately arranged. In the present invention, all of these are fiber reinforced resin layers.

[0067] As described above, in the case of a fiber-reinforced resin layer in which a resin layer consisting of only a binder resin and a fibrous layer in which a fiber aggregate is impregnated with the binder resin are alternately arranged, the thickness of the resin layer is preferably small. This is because the smaller the thickness of the resin layer, the higher the fiber content of the entire fiber-reinforced resin material, and the improved mechanical properties. From this viewpoint, the resin layer is preferably 5000 μm or less, and may 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 can be measured by scanning electron microscope observation. More specifically, the thickness is measured at 10 arbitrary points in a still image of an enlarged cross section of the fiber-reinforced resin material in the lamination direction, and the average value of the measured thicknesses is regarded as the layer thickness.

[0068] The number of fiber-reinforced resin layers in the fiber-reinforced resin material is not limited, but can be, for example, 2 to 100,000 layers, 3 to 10,000 layers, 4 to 1,000 layers, or 5 to 100 layers.

[0069] In addition, in this fiber-reinforced resin material, the fact that the second layer is more ductile and has a lower elasticity than the first layer, and that the third layer is more ductile and has a lower elasticity than the second layer, can be demonstrated by removing or reproducing each layer and performing a three-point bending test at the same load application rate using an autograph, and comparing the elastic modulus and fracture strain at the time of fracture of the test piece between each two layers.

[0070] The use of the fiber reinforced resin material is not limited, and for example, either the first layer side (relatively low ductility and high elasticity side) or the third layer side (high ductility and low elasticity side) may be used as the impact input side. Of these, it is preferable to use the first layer side as the impact input side. In this case, it is possible to exhibit dramatically higher mechanical properties compared to the case where the third layer side is used as the impact input side. In particular, it is possible to obtain a remarkable bending stress. Specifically, the bending stress when the first layer side is used as the impact input side can be improved by 120% or more (further 130% to 300%, further 150% to 250%) compared to the bending stress when the third layer side is used as the impact input side.

[0071] [2] Manufacturing method for fiber-reinforced resin materials The above-mentioned fiber reinforced resin material 1 may be produced in any manner, but can be produced by a method including a lamination step and a heat pressing step. Among these, the lamination process is a process of laminating a sheet-like material of continuous fibers that will become the fiber assembly and a resin sheet that will become the binder resin (the first thermoplastic resin, the second thermoplastic resin, or the third thermoplastic resin) so as to obtain a laminated structure (see Figures 2 to 5). The hot pressing step is a step of heating and compressing the laminate obtained through the lamination step in the lamination direction (see Figs. 2 to 5).

[0072] The above-mentioned "sheet-like material (W)" is a sheet-like fiber assembly, and is formed by assembling continuous fibers W1 into a sheet. The continuous fibers W1 are as described above, and are not substantially changed before and after the fiber-reinforced resin material is formed. In the sheet-like material W, the continuous fibers W1 may be assembled in any manner. That is, for example, the continuous fibers W1 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 W may be composed of only one continuous fiber layer in which the continuous fibers W1 are arranged in layers, or may be composed of two or more continuous fiber layers. The above-mentioned "resin sheet (S)" is a sheet-like material containing a binder resin S1. The thermoplastic resin constituting this resin sheet S is as described above, and is not substantially changed before and after it is made into the fiber reinforced resin material 1.

[0073] In the lamination step, the sheet-like material W and the resin sheet S 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 may also be performed so that the desired laminate structure is obtained through two or more heat-pressing steps. That is, for example, a laminate to become the first layer (see FIG. 2), a laminate to become the second layer (see FIG. 3), and a laminate to become the third layer (see FIG. 4) may be separately formed, and the obtained laminates may be further laminated (see FIG. 5), and the desired fiber-reinforced resin material may be obtained by heat-compression. That is, the fiber-reinforced resin material can be obtained by finally integrating the laminates while performing the divided lamination in this manner. 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.

[0074] 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 particles and the above-mentioned composite resin and polyamide are selected as the binder resin, 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 a plurality of heat and pressure steps are performed to obtain one sheet of fiber reinforced resin material, the heating temperature and pressure in each step may be the same or different.

[0075] [3] Fiber-reinforced resin structure The fiber-reinforced resin structure of the present invention is made of the above-mentioned fiber-reinforced resin material. 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.

[0076] 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.

[0077] 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

[0078] The present invention will now be described in detail with reference to examples. [1] Materials used (1-1) Sheet-like material W (PA6 particles attached) Particle W as continuous fiber W1 12 Carbon fiber with PA6 particles attached was used. 11 The sizing agent used was "HTS40" (24K) manufactured by Toho Tenax Co., Ltd. After removing the sizing agent 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 W1 in which PA6 particles were attached to about 30 to 100 area % of the surface of the base carbon fiber. 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.

[0079] (1-2) Resin sheet S using PA6 (S PA6 ) Resin sheet: PA6 (manufactured by Toray Industries, Inc., product name "CM1001") pellets are molded into a sheet with a thickness of 70 to 110 μm by heat pressing. Incidentally, PA6 corresponds to the thermoplastic resin B, which is a polyamide resin.

[0080] (1-3) Resin sheet S using composite resin A (S A ) Composite resin A: A composite resin having a PP matrix composed of PP, PA11, and a compatibilizer (manufactured by Toyota Boshoku Corporation). Specifically, a composite resin obtained by melt-kneading polypropylene (homopolymer with a 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 S A : Composite resin A molded into a sheet with a thickness of 160 μm In addition, PP corresponds to the polyolefin resin which is the thermoplastic resin A, and PA11 corresponds to the polyamide resin which is the thermoplastic resin B.

[0081] (1-4) Resin sheet S using composite resin C (S C ) Composite resin C: A composite resin having a PA matrix of PP, PA6, and a compatibilizer (manufactured by Toyota Boshoku Corporation). Specifically, a composite resin melt-kneaded with 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 10%:60%:30% (melt-kneaded mixture of PA6 and compatibilizer with PP). Resin Sheet S C : Composite resin C molded into a sheet with a thickness of 160 μm In addition, PP corresponds to the polyolefin resin, which is the thermoplastic resin A, and PA6 corresponds to the polyamide resin, which is the thermoplastic resin B.

[0082] [2] Preparation of fiber-reinforced resin material (2-1) Experimental Example 1: Fiber-reinforced resin material having laminated structure T1 As shown in Figure 2, four resin sheets S (S PA6 A laminate 11" was formed by inserting three sheet-like materials W between the layers of the laminate 11, and this laminate 11" was heated and pressurized under conditions of a temperature of 230°C and a pressure of 0.3 to 5.0 MPa to obtain a laminate 11' for the first layer 11.

[0083] Similarly, as shown in Figure 3, four resin sheets S (S C A laminate 12" was formed by inserting three sheet-like materials W between the layers of the laminate 12). This laminate 12" was then heated and pressurized at a temperature of 230°C and a pressure of 0.3 to 5.0 MPa to obtain a laminate 12' for the second layer 12.

[0084] Similarly, as shown in Figure 4, four resin sheets S (S A A laminate 13" was formed by inserting three sheet-like materials W between the layers of the laminate 13, and this laminate 13" was heated and pressurized under conditions of a temperature of 230°C and a pressure of 0.3 to 5.0 MPa to obtain a laminate 13' for the third layer 13.

[0085] Thereafter, as shown in Figure 5, a laminate 1' was formed by laminating the first layer laminate 11', the second layer laminate 12', and the third layer laminate 13' in that order, and this laminate 1' was heated and pressurized 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 1 (see Figure 1) as experimental example 1, having a laminate structure T1 (with the first layer on the impact input side) in which the first layer, second layer, and third layer are laminated in that order.

[0086] Furthermore, when comparing the first layer laminate 11' which becomes the first layer 11, with the second layer laminate 12' which becomes the second layer 12, and the third layer laminate 13' which becomes the third layer 13, the second layer 12 has higher ductility and lower elasticity than the first layer 11, and the third layer has higher ductility and lower elasticity than the second layer. This is a resin sheet S PA6 The thermoplastic resin PA6 and the resin sheet S C Composite resin C, which is a thermoplastic resin, and resin sheet S A This is because, when compared with composite resin A, which is a thermoplastic resin having a structure of PA6, composite resin C has higher ductility and lower elasticity than PA6, while composite resin A has higher ductility and lower elasticity than composite resin C.

[0087] That is, the properties of each thermoplastic resin are as follows: PA6: Tensile elongation at break 35%, flexural modulus 2800MPa Composite resin C: Tensile elongation at break 257%, flexural modulus 1088MPa Composite resin A: Tensile elongation at break 310%, flexural modulus 850MPa Among the above values, the tensile elongation at break is measured in accordance with ISO527-1 (ISO multipurpose test piece, tensile speed 50 mm / min). The flexural modulus is measured in the same manner as the three-point bending test in [3](3-1) described later.

[0088] (2-2) Experimental Example 2: Fiber-reinforced resin material having laminated structure T2 The fiber-reinforced resin material 1 of Experimental Example 1 having the laminate structure T1 of (2-1) above was turned over to obtain, as Experimental Example 2, a fiber-reinforced resin material 1 (see FIG. 7) having a laminate structure T2 (with the third layer on the impact input side) in which the third layer, the second layer, and the first layer were laminated in this order.

[0089] (2-3) Experimental Example 3: Fiber-reinforced resin material having laminated structure T3 As shown in Fig. 10(a), six resin sheets S (S PA6 A laminate 15" was formed by inserting five sheet-like materials W between the layers of the laminate 15, and this laminate 15" was heated and pressurized under conditions of a temperature of 230°C and a pressure of 0.3 to 5.0 MPa to obtain an upper layer laminate 15' which would become the upper layer 15. Similarly, as shown in FIG. 10(b), six resin sheets S (S C A laminate 16" was formed by inserting three sheet-like materials W between the layers of the laminate 16, and this laminate 16" was heated and pressurized under conditions of a temperature of 230°C and a pressure of 0.3 to 5.0 MPa to obtain a lower layer laminate 16' which would become the lower layer 16. Then, as shown in Figure 10(c), a laminate 1' was formed by stacking the upper layer laminate 15' and the lower layer laminate 16' in this order, and this laminate 1' was heated and pressurized 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 1 (see Figure 8) as experimental example 3, having a laminate structure T3 (with the upper layer on the impact input side) in which the upper layer and lower layer were stacked in this order.

[0090] (2-4) Experimental Example 4: Fiber-reinforced resin material having laminated structure T4 The fiber-reinforced resin material 1 (see FIG. 8) of Experimental Example 3 having the laminate structure T3 of (2-3) above was turned over to obtain, as Experimental Example 4, a fiber-reinforced resin material 1 (see FIG. 9) having a laminate structure T4 (with the lower layer on the impact input side) in which a lower layer and an upper layer were laminated in this order.

[0091] [Table 1]

[0092] [3] Evaluation (3-1) Three-point bending test In accordance with JIS K7074, in each of Experimental Examples 1 to 4, two test pieces (width 12 mm, thickness 2.4 mm, length 100 mm) were used, and a three-point bending test was performed by applying a load from the upper side of each structure (for example, the first layer 11 side in structure T1) at a support distance of 80 mm and a bending speed of 5 mm / min, to measure the bending stress, bending modulus, and strain. The results are shown in Table 1 as the average values ​​measured for the two test pieces.

[0093] (3-2) Stress-strain curve The test pieces (width 12 mm, thickness 2.4 mm, length 100 mm) of each of Experimental Examples 1 to 4 were attached to an autograph (model "AGS-X", manufactured by Shimadzu Corporation), and a three-point bending test was performed by applying a load from the upper side of each structure (for example, the first layer 11 side in structure T1) with a support distance of 80 mm and a bending speed of 5 mm / min, to obtain stress-strain curves. The obtained stress-strain curves were multi-charted and shown in FIG.

[0094] (3-3) Observation of fracture site An image of the vicinity of the fractured portion of the test piece of Experimental Example 1 was taken at a magnification of 50 times using a digital microscope (model "KH-8700", manufactured by Hirox Corporation), and is shown in FIG.

[0095] From the results of Table 1, FIG. 11 and FIG. 12, it is understood that in Experimental Example 2 (Structure T2) and Experimental Example 4 (Structure T4), the fracture occurred after the maximum stress was reached. In contrast, it is understood that in Experimental Example 1 (Structure T1) and Experimental Example 3 (Structure T3), the stress was maintained while the strain was increased even after the maximum stress was reached. In particular, it is understood that in Experimental Example 1 (Structure T1), the stress of about 130 to 180 MPa can be maintained while the strain is increased. Although the reason why the stress can be maintained while being strained in this manner is not clear, it is confirmed from FIG. 12 that although the first layer 11 (binder resin is PA6) is broken at X2, separation does not occur at the interface between the first layer 11 (binder resin is PA6) and the second layer (binder resin is composite resin C). In other words, it is considered that the above-mentioned separation is prevented because PA6 and composite resin C are common as thermoplastic resin B and the content ratio in composite resin C is large. In addition, in order to prevent the above-mentioned separation, the first layer 11 shifts in the stacking direction after fracture as shown by X1, which can be considered to result in the load point moving. These actions are considered to have caused the phenomenon in Experimental Example 1 in which the stress continues to increase for a long time even after reaching the maximum stress. This phenomenon was confirmed in all the test pieces tested.

[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; 10; fiber reinforced resin layer, 11; first fiber-reinforced resin layer; 12; second fiber-reinforced resin layer; 13; third fiber-reinforced resin layer; S1: Binder resin, S: Resin sheet, W1; Reinforced fiber, W 11 ; Fiber, W 12 ;particles, W;sheet-like objects.

Claims

1. A first fiber reinforced resin layer; A second fiber reinforced resin layer having higher ductility and lower elasticity than the first fiber reinforced resin layer; A third fiber reinforced resin layer having higher ductility and lower elasticity than the second fiber reinforced resin layer, The first fiber reinforced resin layer, the second fiber reinforced resin layer, and the third fiber reinforced resin layer are laminated and integrated in this order, The first fiber reinforced resin layer includes a first thermoplastic resin and continuous fibers, The second fiber reinforced resin layer includes a second thermoplastic resin and continuous fibers, The third fiber reinforced resin layer includes a third thermoplastic resin and continuous fibers, The first thermoplastic resin, the second thermoplastic resin, and the third thermoplastic resin are three different thermoplastic resins, A fiber reinforced resin material, characterized in that the first fiber reinforced resin layer side is an impact input side.

2. The first thermoplastic resin, the second thermoplastic resin and the third thermoplastic resin are each selected from thermoplastic resin A, thermoplastic resin B, and composite resins thereof. The fiber reinforced resin material according to claim 1.

3. Each of the continuous fibers has particles attached to a surface thereof; The fiber-reinforced resin material according to claim 2 , wherein the particles are made of any one of the thermoplastic resin A, the thermoplastic resin B, and the composite resin.

4. The fiber reinforced resin material according to claim 1 , wherein the first fiber reinforced resin layer, the second fiber reinforced resin layer, and the third fiber reinforced resin layer have different fiber contents.

5. A fiber-reinforced resin structure comprising the fiber-reinforced resin material according to any one of claims 1 to 4.

6. A method for producing a fiber-reinforced resin material according to any one of claims 1 to 3, A lamination process in which a sheet-like material obtained by forming the continuous fibers into a sheet shape and each resin sheet which is the first thermoplastic resin, the second thermoplastic resin, or the third thermoplastic resin are laminated so as to obtain a laminate structure in which the first fiber reinforced resin layer, the second fiber reinforced resin layer, and the third fiber reinforced resin layer are laminated in this order; 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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