Fiber-reinforced resin molded body and method for manufacturing same, vehicle, and machine body

Abstract

A fiber-reinforced resin molded body (10) is manufactured by heating and compressing a fiber base material (11A to 11D) together with a thermosetting resin (15) so that the thermosetting resin (15) is impregnated in the fiber base material (11A to 11D) and cured, wherein a powder of the thermosetting resin (15A) is arranged in contact with at least one face of the fiber base material (11A to 11D), and the fiber base material (11A to 11D) is heated and compressed together with the powder of the thermosetting resin (15A) by a mold (30) so that the powder of the thermosetting resin (15A) is melted and impregnated in the fiber base material (11A to 11D) and cured.

Description

Technical Field

[0001] This disclosure relates to a fiber-reinforced resin molded body and its manufacturing method, a prepreg for fiber-reinforced resin molding, a fiber-reinforced molded body, a method for manufacturing a fiber-reinforced molded body, a resin sheet, a fiber-reinforced sandwich composite, and a method for manufacturing a fiber-reinforced molded body.

[0002] This application claims priority to Japanese Patent Application No. 2020-116251 filed on July 6, 2020; Japanese Patent Application No. 2020-171081 filed on October 9, 2020; Japanese Patent Application No. 2021-076007 filed on April 28, 2021; Japanese Patent Application No. 2020-171814 filed on October 12, 2020; and Japanese Patent Application No. 2020-206600 filed on December 14, 2020, the contents of which are incorporated herein by reference. Background Technology

[0003] In recent years, fiber-reinforced resin molded bodies, which are made of fiber-based materials such as carbon fiber and glass fiber and thermosetting resins, have been widely used in various fields and applications to improve lightweighting and mechanical strength.

[0004] Especially in transportation equipment such as automobiles, railways, and airplanes, where there is a high demand for low fuel consumption, the effect of achieving low fuel consumption through the lightweighting of vehicles and bodies is significant. Therefore, it is expected that lightweight fiber-reinforced resin molded parts can be used as metal substitutes.

[0005] One method for manufacturing fiber-reinforced resin molded articles is to impregnate a fiber substrate with a thermosetting resin to form a prepreg, and then mold the prepreg using an autoclave or hot press.

[0006] The thermosetting resin impregnated in the fiber substrate during the production of prepregs is generally in liquid form. However, liquid resins have a limited pot life, which leads to problems with the working environment and air pollution when solvents are used.

[0007] As a solution to these problems, a prepreg made of powdered resin has been proposed (Patent Document 1).

[0008] In addition, as a molding method that does not use prepreg, there is a method in which a preform is made from a fiber substrate, the preform is inserted into a mold, and liquid resin is injected to cure it, thereby obtaining a molded body (RTM (Resin Transfer Molding) process).

[0009] In addition, a lightweight fiber-reinforced sandwich composite is proposed, which is obtained by laminating a prepreg and a core material and then hot stamping it (Patent Document 2).

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: Japanese Patent Application Publication No. 2006-232915

[0013] Patent Document 2: Japanese Patent Application Publication No. 2020-44811 Summary of the Invention

[0014] The problem the invention aims to solve

[0015] However, in molding methods using prepregs, even when using either liquid or powdered resins, large equipment is required in the prepreg process, and the prepreg process management is complex, resulting in higher manufacturing costs for fiber-reinforced resin molded articles.

[0016] In addition, in the RTM process without using prepreg, preforms need to be made and equipment is required to inject liquid resin into the mold at high pressure and per unit weight. Therefore, similar to the case where prepreg is used, the manufacturing cost of fiber-reinforced resin molded articles increases.

[0017] Furthermore, for prepregs using conventional powdered resins (Patent Document 1), the complex process of melting and mixing multiple solid epoxy resins, tetracarboxylic dianhydride, and curing accelerators together to produce an epoxy resin composition, followed by pulverizing the epoxy resin composition to produce powdered resin, is a major cause of increased costs. Additionally, since the epoxy resin composition used as a raw material for powdered resin contains curing accelerators, the prepreg may still cure due to the curing accelerator after production, resulting in insufficient storage stability and sometimes affecting the quality of fiber-reinforced resin molded from the prepreg.

[0018] In addition, during the storage process before use, the curing reaction of the prepreg is slow even at room temperature, resulting in poor storage stability. This can sometimes affect the quality of fiber-reinforced resin molded bodies and sandwich structures obtained by using the stored prepreg.

[0019] This disclosure was made in order to solve at least one of the problems described above.

[0020] means for solving problems

[0021] <First Form>

[0022] A fiber-reinforced resin molded article is formed by heating and compressing a fiber substrate together with a thermosetting resin to impregnate and cure the thermosetting resin in the fiber substrate, characterized in that the cured thermosetting resin is formed by melting and curing a powder of the thermosetting resin disposed in contact with the fiber substrate during the heating and compression.

[0023] A fiber-reinforced molded article, characterized in that the fiber substrate comprises multiple layers.

[0024] A method for manufacturing a fiber-reinforced resin molded article involves heating and compressing a fiber substrate and a thermosetting resin together, impregnating the fiber substrate with the thermosetting resin, and then curing it. The method is characterized in that...

[0025] The thermosetting resin powder is configured to contact the fiber substrate.

[0026] The fiber substrate and the thermosetting resin powder are heated and compressed together using a mold, thereby melting the thermosetting resin powder and impregnating it within the fiber substrate, whereby it is then cured.

[0027] A method for manufacturing a fiber-reinforced resin molded article, characterized in that the fiber substrate is configured as a multilayer, and the powder of the thermosetting resin is disposed on at least one side of the multilayer fiber substrate.

[0028] A method for manufacturing a fiber-reinforced resin molded body, characterized in that, when the melting start temperature of the thermosetting resin is set to Ta℃ and the curing reaction start temperature is set to Tb℃, the temperature Tc℃ of the mold is [Tb+(Tb-Ta) / 3]-15≤Tc≤[Tb+(Tb-Ta) / 3]+20.

[0029] A method for manufacturing a fiber-reinforced resin molded body, characterized in that, when the melting start temperature of the thermosetting resin is set to Ta℃ and the curing reaction start temperature is set to Tb℃, the value of (Tb-Ta) is 30≤(Tb-Ta)≤100.

[0030] A method for manufacturing a fiber-reinforced resin molded article, characterized in that the minimum viscosity of the thermosetting resin at a temperature above the melting start temperature Ta℃ is below 2000 Pa·s.

[0031] A method for manufacturing a fiber-reinforced resin molded article, characterized in that the thermosetting resin has a maximum viscosity of 1000 Pa·s or higher within a temperature range of Tb℃ to 190℃ during the curing reaction.

[0032] A method for manufacturing a fiber-reinforced resin molded article, characterized in that the melting start temperature Ta of the thermosetting resin is 60-100℃.

[0033] A method for manufacturing a fiber-reinforced resin molded article, characterized in that the thermosetting resin is a resin selected from the group consisting of phenolic resin, a mixed resin of phenolic resin and epoxy resin, a mixed resin of phenolic resin and cyanate ester resin, and a mixed resin of phenolic resin, cyanate ester resin and epoxy resin.

[0034] <Second Form>

[0035] A fiber-reinforced resin prepreg for molding is obtained by heating and compressing a fiber substrate together with a thermosetting resin. The thermosetting resin is characterized in that it is in powder form before heating and compression, has a viscosity of less than 2000 Pa·s at the curing reaction start temperature Tb℃, and has a maximum viscosity of more than 1000 Pa·s within the range of curing reaction start temperature Tb℃ to 190℃.

[0036] A fiber-reinforced resin prepreg for molding, characterized in that the melt start temperature Ta of the thermosetting resin is 60-100°C.

[0037] A fiber-reinforced resin prepreg for molding, wherein the value of the curing reaction start temperature Tb℃ - melting start temperature Ta℃ of the thermosetting resin is 30≤(Tb-Ta)≤100.

[0038] A fiber-reinforced resin prepreg for molding, characterized in that the melting start temperature Ta℃ of the thermosetting resin is below the temperature during heating and compression, and the curing reaction start temperature Tb℃ is above the temperature during heating and compression.

[0039] A fiber-reinforced resin prepreg for molding, characterized in that the melting start temperature Ta℃ of the thermosetting resin is below -5℃ of the temperature during heating and compression, and the curing reaction start temperature Tb℃ is above +5℃ of the temperature during heating and compression.

[0040] A fiber-reinforced resin prepreg for molding, characterized in that the thermosetting resin is a resin selected from the group consisting of phenolic resin, a mixture of phenolic resin and epoxy resin, a mixture of phenolic resin and cyanate ester resin, and a mixture of phenolic resin, cyanate ester resin and epoxy resin.

[0041] A fiber-reinforced resin molded body is formed by heating and compressing a fiber-reinforced resin molding prepreg to cure it.

[0042] <Third Form>

[0043] A fiber-reinforced molded body is formed by integrally passing a fiber substrate through a resin sheet containing a thermosetting resin, wherein the viscosity of the thermosetting resin at the curing reaction start temperature Tb℃ is less than 2000 Pa·s, and the maximum viscosity within the range of the curing reaction start temperature Tb℃ to 190℃ is more than 1000 Pa·s.

[0044] A fiber-reinforced molded body, wherein the resin sheet has a sheet substrate.

[0045] A fiber-reinforced molded body, wherein when the melting start temperature of the thermosetting resin is set to Ta℃ and the curing reaction start temperature is set to Tb℃, the value of (Tb-Ta) satisfies 30≤(Tb-Ta)≤100.

[0046] A fiber-reinforced molded body, wherein the thermosetting resin is selected from the group consisting of phenolic resin, a mixture of phenolic resin and epoxy resin, a mixture of phenolic resin and cyanate ester resin, a mixture of epoxy resin and cyanate ester resin, and a mixture of phenolic resin, cyanate ester resin and epoxy resin.

[0047] A method for manufacturing a fiber-reinforced molded body involves heating and compressing a fiber substrate and a resin sheet in an overlapping state using a mold, thereby impregnating the thermosetting resin in the fiber substrate and curing it.

[0048] A method for manufacturing a fiber-reinforced molded body, wherein the temperature Tc during heating and compression is [Tb+(Tb-Ta) / 3]-15≤Tc≤[Tb+(Tb-Ta) / 3]+20.

[0049] A resin sheet for manufacturing fiber-reinforced molded articles, wherein the resin contains a thermosetting resin.

[0050] <Fourth Form>

[0051] A fiber-reinforced sandwich composite is formed by laminating a fiber substrate and a core material and bonding them together with a thermosetting resin through heating and compression, characterized in that...

[0052] The core material has a 5% compressive stress of 0.10 MPa or higher.

[0053] The thermosetting resin is in powder form before heating, and its viscosity at the curing reaction start temperature Tb℃ is below 2000 Pa·s, while its maximum viscosity within the range of curing reaction start temperature Tb℃ to 190℃ is above 1000 Pa·s.

[0054] A fiber-reinforced sandwich composite, characterized in that, in the thermosetting resin, the melting start temperature Ta℃ and the curing reaction start temperature Tb℃ are [Tb+(Tb-Ta) / 3]-15≤Tc≤[Tb+(Tb-Ta) / 3]+20, relative to the temperature Tc℃ during heating and compression.

[0055] A fiber-reinforced sandwich composite, characterized in that the value of the curing reaction start temperature Tb℃ - melting start temperature Ta℃ of the thermosetting resin is 30≤(Tb-Ta)≤100.

[0056] A fiber-reinforced sandwich composite, characterized in that the melt start temperature Ta of the thermosetting resin is 60-100°C.

[0057] A fiber-reinforced sandwich composite, characterized in that the core material is a foam with an independent bubble structure.

[0058] A fiber-reinforced sandwich composite, characterized in that the thermosetting resin is a resin selected from the group consisting of phenolic resin, a mixture of phenolic resin and epoxy resin, a mixture of phenolic resin and cyanate ester resin, and a mixture of phenolic resin, cyanate ester resin and epoxy resin.

[0059] <Fifth Form>

[0060] A method for manufacturing a fiber-reinforced molded body, wherein the fiber-reinforced molded body is formed by laminating and integrally bonding a core material impregnated and cured with a thermosetting resin in a resin foam with a fiber reinforcing material impregnated and cured with the thermosetting resin in a fiber matrix, characterized in that...

[0061] The resin foam has a continuous bubble structure.

[0062] A pre-molding laminate is formed by the resin foam having the continuous bubble structure, the thermosetting resin, and the fiber substrate.

[0063] The thermosetting resin is melted by heating and compressing the pre-molded laminate, and the molten thermosetting resin is impregnated in the resin foam having the continuous bubble structure and the fiber substrate and then cured.

[0064] A method for manufacturing a fiber-reinforced molded body, characterized in that the fiber substrate is disposed on both sides of a resin foam having a continuous bubble structure in the pre-molding laminate.

[0065] A method for manufacturing a fiber-reinforced molded body, characterized in that the thermosetting resin in the pre-molded laminate is in powder form, with a viscosity of less than 2000 Pa·s at the curing reaction start temperature Tb℃, and a maximum viscosity of more than 1000 Pa·s within the range of curing reaction start temperature Tb℃ to 190℃.

[0066] A method for manufacturing a fiber-reinforced molded article, characterized in that, in the thermosetting resin, the melting start temperature Ta℃ and the curing reaction start temperature Tb℃ are [Tb+(Tb-Ta) / 3]-15≤Tc≤[Tb+(Tb-Ta) / 3]+20, relative to the temperature Tc℃ during heating and compression.

[0067] A method for manufacturing a fiber-reinforced molded body, characterized in that the value of the curing reaction start temperature Tb℃ - melting start temperature Ta℃ of the thermosetting resin is 30≤(Tb-Ta)≤100.

[0068] A method for manufacturing a fiber-reinforced molded article, characterized in that the melting start temperature Ta of the thermosetting resin is 60-100℃.

[0069] A method for manufacturing a fiber-reinforced molded article, characterized in that the resin ratio specified by the following formula (A1) is 50-80%;

[0070] [Formula 1]

[0071] (A1)

[0072]

[0073] A method for manufacturing a fiber-reinforced molded article, characterized in that the compression rate is 200 to 5000% as specified by the following formula (A2);

[0074] [Equation 2]

[0075] (A2)

[0076]

[0077] A method for manufacturing a fiber-reinforced molded article, characterized in that the thermosetting resin is a resin selected from the group consisting of phenolic resin, a mixed resin of phenolic resin and epoxy resin, a mixed resin of phenolic resin and cyanate ester resin, and a mixed resin of phenolic resin, cyanate ester resin and epoxy resin.

[0078] A fiber-reinforced molded body is formed by laminating and integrally bonding a core material impregnated and cured with a thermosetting resin in a resin foam having a continuous bubble structure, and a fiber reinforcing material impregnated and cured with the thermosetting resin in a fiber matrix.

[0079] The viscosity of the thermosetting resin at the curing reaction start temperature Tb℃ is below 2000 Pa·s, and the highest viscosity within the range of curing reaction start temperature Tb℃ to 190℃ is above 1000 Pa·s.

[0080] The effects of the invention

[0081] <First Form>

[0082] According to the first embodiment of the fiber-reinforced resin molded article, by configuring and using a powdered thermosetting resin in contact with a fiber substrate, a high-strength, high-rigidity fiber-reinforced resin molded article can be obtained in a manner that does not require solvents, does not cause concern about environmental pollution, and has no shelf life.

[0083] According to the invention of the method for manufacturing fiber-reinforced resin molded articles, since the powder of thermosetting resin is prepared to contact the fiber matrix, and the powder of thermosetting resin and the fiber matrix are heated and compressed together, the fiber-reinforced resin molded article is manufactured. Therefore, the production of prepreg or preforms such as RTM process is not required, and the use of solvents for liquid thermosetting resin is not required, so there is no concern about environmental pollution. There is also no issue of the shelf life of thermosetting resin. Therefore, it is possible to manufacture high-strength and high-rigidity fiber-reinforced resin molded articles simply, cheaply, without concern for environmental pollution, and safely.

[0084] In the relationship between the melting start temperature Ta℃ and the curing reaction start temperature Tb℃ of thermosetting resin, by setting the mold temperature Tc℃ to [Tb+(Tb-Ta) / 3]-15≤Tc≤[Tb+(Tb-Ta) / 3]+20, the fiber substrate and the thermosetting resin powder are heated and compressed together. As a result, the melting of the thermosetting resin powder in contact with the fiber substrate becomes better, and the thermosetting resin is easily impregnated into the fiber substrate. This enables the production of fiber-reinforced resin molded bodies with uniform physical properties with high production efficiency.

[0085] By using a thermosetting resin with a content of 30 ≤ (Tb-Ta) ≤ 100, the molten thermosetting resin can be fully impregnated into the fiber matrix, thus enabling the manufacture of fiber-reinforced resin molded articles with uniform physical properties.

[0086] By using a thermosetting resin with a minimum viscosity of 2000 Pa·s at a temperature above the melting start temperature Ta℃, the molten thermosetting resin can be fully impregnated into the fiber matrix, thus enabling the manufacture of fiber-reinforced resin molded articles with uniform physical properties.

[0087] With a maximum viscosity of over 1000 Pa·s within the temperature range of Tb℃~190℃, the thermosetting resin can impregnate and remain in the fiber matrix, resulting in good shapeability of the fiber-reinforced resin molded body and the ability to obtain sufficient strength in a short time.

[0088] Since the melting start temperature Ta of thermosetting resin is 60-100℃, temperature adjustment becomes easy when thermosetting resin powder is heated and compressed together with fiber matrix to melt and solidify thermosetting resin.

[0089] By selecting a thermosetting resin from the group consisting of phenolic resin, a mixture of phenolic resin and epoxy resin, a mixture of phenolic resin and cyanate ester resin, and a mixture of phenolic resin, cyanate ester resin and epoxy resin, fiber-reinforced resin molded articles with excellent strength and flame retardancy can be obtained.

[0090] <Second Form>

[0091] According to the second method, the prepreg is simple and inexpensive to produce, and can produce prepreg with good preservation stability and fiber-reinforced resin molded articles with good quality made from the prepreg.

[0092] <Third Form>

[0093] The third type of fiber-reinforced molded body can be manufactured inexpensively.

[0094] <Fourth Form>

[0095] According to the fourth form, it is possible to obtain a fiber-reinforced sandwich composite material that is integrated with the core material, which can be manufactured simply, cheaply, without worrying about environmental pollution, and safely, without the need for prepreg or the need to consider the storage stability of the prepreg.

[0096] <Fifth Form>

[0097] According to the fifth aspect, fiber-reinforced molded articles can be obtained without the use of prepreg. Furthermore, according to the fifth aspect, fiber-reinforced molded articles with an uneven or concave shape can also be obtained. Attached Figure Description

[0098] Figure 1 This is a cross-sectional view of a fiber-reinforced resin molded body according to one embodiment of the first form.

[0099] Figure 2 This is a cross-sectional view showing the lamination and thermal compression in one embodiment of a method for manufacturing a fiber-reinforced resin molded article of the first form.

[0100] Figure 3 This is a cross-sectional view showing the lamination and thermal compression in another embodiment of the method for manufacturing the fiber-reinforced resin molded article of the first form.

[0101] Figure 4 This is a table showing the melting start temperature, reaction start temperature, etc. of the thermosetting resins used in each embodiment and comparative example for the first form.

[0102] Figure 5 This is a table showing the structure and physical properties of each embodiment and comparative example in relation to the first form.

[0103] Figure 6 The graphs show the viscosity measurement results of the thermosetting resins used in Examples 1A to 3A and Comparative Examples 1A and 2A for the first morphology.

[0104] Figure 7 This is a cross-sectional view showing the fiber-reinforced resin prepreg for molding according to the first embodiment of the second form and the heat compression during its production.

[0105] Figure 8 This is a cross-sectional view showing the fiber-reinforced resin molding prepreg of the second embodiment of the second form and the heat compression during its production.

[0106] Figure 9 This is a cross-sectional view showing the fiber-reinforced resin prepreg for molding according to the third embodiment of the second form and the heat compression during its production.

[0107] Figure 10 This is a table showing the melt start temperature, curing reaction start temperature, etc. of the thermosetting resins used in the fiber-reinforced resin molding prepregs of each embodiment and comparative example for the second type.

[0108] Figure 11 The graph shows the viscosity measurement results of the thermosetting resin used in the fiber-reinforced resin molding prepregs of Examples 1B to 3B and Comparative Examples 1B and 2B for the second morphology.

[0109] Figure 12 This table shows the structure and physical properties of fiber-reinforced resin molded articles made from the fiber-reinforced resin molding prepregs of each embodiment and each comparative example, with respect to the second aspect.

[0110] Figure 13 The table shows the appearance, physical properties, etc. of a fiber-reinforced resin molded body made using the fiber-reinforced resin prepreg of Examples 1B, 4B to 7B 90 days after its preparation, for the second embodiment.

[0111] Figure 14 This is a cross-sectional view of a fiber-reinforced molded body according to one embodiment of the third form.

[0112] Figure 15 This is a cross-sectional view illustrating the lamination and thermal compression in one embodiment of the manufacturing method of the fiber-reinforced molded article of the present invention.

[0113] Figure 16This is a cross-sectional view showing the lamination and thermal compression in one embodiment of a method for manufacturing a fiber-reinforced molded body of the third form.

[0114] Figure 17 This is a cross-sectional view showing the lamination and thermal compression in one embodiment of a method for manufacturing a fiber-reinforced molded body of the third form.

[0115] Figure 18 The graphs show the viscosity measurement results of the mixed resins used in Examples 1C, 6C to 10C and Comparative Examples 1C and 2C for the third morphology.

[0116] Figure 19 This is a cross-sectional view of a fiber-reinforced sandwich composite of one embodiment of the fourth form.

[0117] Figure 20 This is a cross-sectional view showing the lamination and thermal compression in one embodiment of a method for manufacturing a fiber-reinforced sandwich composite of the fourth type.

[0118] Figure 21 This is a table showing the material, thickness, etc. of the core material used in each embodiment and comparative example for the fourth aspect.

[0119] Figure 22 This is a table showing the melting start temperature, curing reaction start temperature, etc. of the thermosetting resins used in each embodiment and comparative example for the fourth aspect.

[0120] Figure 23 This is a table showing the composition and physical properties of each embodiment and comparative example for the fourth form.

[0121] Figure 24 The graph shows the viscosity measurement results of the thermosetting resins used in Examples 1D, 6D, 7D and Comparative Examples 2D, 3D for the fourth morphology.

[0122] Figure 25 This is a cross-sectional view of the fiber-reinforced molded body of the first embodiment of the fifth form.

[0123] Figure 26 It is designed for the fifth form. Figure 25 A cross-sectional view of the lamination and thermal compression in one embodiment of the method for producing fiber-reinforced molded articles.

[0124] Figure 27 This is shown in response to the fifth form. Figure 25 A cross-sectional view of the lamination and thermal compression in another embodiment of the method for manufacturing fiber-reinforced molded articles.

[0125] Figure 28 This is a cross-sectional view of the fiber-reinforced molded body of the second embodiment of the fifth form.

[0126] Figure 29 It shows the manufacturing process. Figure 28 A cross-sectional view of the lamination and thermal compression in one embodiment of the method for producing fiber-reinforced molded articles.

[0127] Figure 30 This is a cross-sectional view of the fiber-reinforced molded body of the third embodiment of the fifth form.

[0128] Figure 31 It shows the manufacturing process. Figure 30 A cross-sectional view of the lamination and thermal compression in one embodiment of the method for producing fiber-reinforced molded articles.

[0129] Figure 32 This is a cross-sectional view of the fiber-reinforced molded body of the fourth embodiment of the fifth form.

[0130] Figure 33 It is designed for the fifth form. Figure 32 A cross-sectional view of the lamination and thermal compression in one embodiment of the method for producing fiber-reinforced molded articles.

[0131] Figure 34 It is designed for the fifth form. Figure 32 A cross-sectional view of the lamination and thermal compression in other embodiments of the method for producing fiber-reinforced molded articles.

[0132] Figure 35 This is a table showing the types of powdered thermosetting resins used in each embodiment and comparative example, as well as their melting start temperature and curing reaction start temperature, for the fifth embodiment.

[0133] Figure 36 This is a table showing the composition and physical properties of each embodiment and comparative example for the fifth form.

[0134] Figure 37 The graphs show the viscosity measurement results of the thermosetting resins used in Examples 1E, 6E to 15E and 20E to 26E and Comparative Examples 1E to 4E for the fifth type. Detailed Implementation

[0135] The following details this disclosure. Furthermore, in this specification, where “~” is used to indicate a numerical range, both the lower and upper limits are included unless otherwise specified. For example, in the description “10 to 20”, both the lower limit “10” and the upper limit “20” are included. That is, “10 to 20” has the same meaning as “more than 10 and less than 20”.

[0136] <First Form>

[0137] The implementation method of the first form will be described. Figure 1The fiber-reinforced resin molded body 10 shown in one embodiment is a structure in which multiple stacked fiber substrates 11 are heated and compressed together with thermosetting resin 15, and the thermosetting resin 15 is cured to form an integral structure.

[0138] The fiber substrate 11 can be a single layer or multiple layers, and the number of layers is determined according to the application of the fiber-reinforced resin molded body 10. In the embodiments shown in the drawings, the fiber substrate 11 consists of four layers. The fiber substrate 11 can be a fabric or nonwoven fabric made of glass fiber, aramid fiber, basalt fiber, carbon fiber, etc., and is not particularly limited. Carbon fiber fabric is preferred due to its excellent lightweight and high rigidity. As for the carbon fiber fabric, fabrics woven in a way that involves weaving fibers in more than one direction are preferred; for example, plain weave fabrics, twill weave fabrics, satin weave fabrics, and triaxial fabrics made of yarns in three directions are preferred. Furthermore, from the viewpoint of the impregnation of the thermosetting resin 15 and the rigidity of the fiber-reinforced resin molded body 10, the fiber weight of the aforementioned carbon fiber fabric is preferably 50 to 600 g / m². 2 .

[0139] When manufacturing the fiber-reinforced resin molded body 10, the thermosetting resin 15 is a solid powder. The shape of the powder is not particularly limited, including spherical, needle-like, and flake-like forms. The thermosetting resin powder is positioned to contact the fiber substrate 11, and melts when the fiber substrate 11 and the thermosetting resin powder are heated and compressed together, thus solidifying and impregnating the fiber substrate 11. Examples of the configuration in which the thermosetting resin powder contacts the fiber substrate 11 include: when the fiber substrate 11 is a single layer, it is disposed on at least one of the upper or lower surfaces of the single-layer fiber substrate 11; and when the fiber substrate 11 is multilayered, it is disposed on at least one of the uppermost surface, lowermost surface, or lamination surface (between fiber substrates) of the multilayer.

[0140] When the melting start temperature of the thermosetting resin 15 is set to Ta℃ and the curing reaction start temperature is set to Tb℃, it is preferable that 30≤(Tb-Ta)≤100, and more preferably 40≤(Tb-Ta)≤70. By setting (Tb-Ta) within this range, the molten thermosetting resin 15 can be fully impregnated in the fiber substrate 11, and a fiber-reinforced resin molded body 10 with uniform physical properties can be obtained.

[0141] At a temperature above the melting start temperature Ta°C, the thermosetting resin 15 preferably has a minimum viscosity of 2000 Pa·s or less, more preferably 1500 Pa·s or less. By setting the minimum viscosity to this range, the molten thermosetting resin 15 can be fully impregnated in the fiber substrate 11, and a fiber-reinforced resin molded article 10 with uniform physical properties can be obtained.

[0142] Furthermore, within the temperature range of the curing reaction start temperature Tb℃ to 190℃, the thermosetting resin 15 preferably has a maximum viscosity of 1000 Pa·s or higher. By setting the maximum viscosity within this range, the molten thermosetting resin 15 can be impregnated and retained within the fiber substrate 11, resulting in good shapeability of the fiber-reinforced resin molded body 10 and the attainment of sufficient strength in a short time.

[0143] Preferably, the melting start temperature Ta of the thermosetting resin 15 is 60 to 100°C. By setting the melting start temperature Ta of the thermosetting resin 15 to this range, the temperature can be easily adjusted when the thermosetting resin 15 is melted and cured by heating and compressing a laminate in which at least one layer of the thermosetting resin 15 powder is disposed between the fiber substrates 11.

[0144] For thermosetting resins that satisfy the above-mentioned melt start temperature Ta℃, curing reaction start temperature Tb℃, (Tb-Ta) range, minimum viscosity, and maximum viscosity, it is preferable to select from the group consisting of phenolic resins, mixtures of phenolic resins and epoxy resins, mixtures of phenolic resins and cyanate ester resins, and mixtures of phenolic resins, cyanate ester resins, and epoxy resins. Phenolic resins have excellent flame retardancy, thus imparting excellent strength and flame retardancy to the fiber-reinforced resin molded body 10.

[0145] In addition, various powder additives such as pigments, antibacterial agents, and ultraviolet absorbers can be added to the thermosetting resin 15 within a range that does not affect the viscosity or reactivity of the thermosetting resin.

[0146] The method for manufacturing this type of fiber-reinforced resin molded article is carried out by: preparing thermosetting resin powder into contact with a fiber substrate; heating and compressing the fiber substrate and the thermosetting resin powder together in a mold, thereby melting the thermosetting resin powder and impregnating it within the fiber substrate, and then curing it. The fiber substrate and the thermosetting resin are as described above for the fiber-reinforced resin molded article 10.

[0147] The morphology of the thermosetting resin powder is as described above. In the case of a single layer, it is disposed on at least one of the upper or lower surfaces of the fiber substrate; in the case of a multilayer fiber substrate, it is disposed on at least one of the uppermost surface, the lowermost surface, and the laminated surface (between fiber substrates) of the multilayer.

[0148] Furthermore, when the thermosetting resin powder is disposed on the laminated surface (between fiber substrates) of a multilayer fiber substrate, it is not limited to one laminated surface (between one fiber substrate), but can be disposed on all laminated surfaces (between all fiber substrates), or laminated surfaces separated by a specified number of layers (between fiber substrates separated by a specified number of layers). The position and number of disposed surfaces can be appropriately determined according to the number of layers of the fiber substrate.

[0149] In addition, when thermosetting resin powder is disposed in contact with the upper or lower surface of a single-layer fiber substrate, or the uppermost or lowermost surface of a multi-layer fiber substrate, release paper may be disposed between the thermosetting resin powder and the mold surface of the mold for ease of operation.

[0150] use Figure 2 illustrate Figure 1 This is one embodiment of a method for manufacturing a fiber-reinforced resin molded body 10 composed of four fiber substrates 11. Furthermore, in the following description of the manufacturing method, for the plurality of fiber substrates 11, in order to easily grasp their vertical positional relationship, multiple fiber substrates 11 are represented by reference numerals combining "11" and "letters," such as "11A."

[0151] exist Figure 2 In the illustrated embodiment, when four fiber substrates 11A to 11D are stacked, thermosetting resin powder 15A is disposed between the lower two fiber substrates 11A and 11B and the upper two fiber substrates 11C and 11D (between fiber substrate 11B and fiber substrate 11C). From the viewpoint of easy melting, it is preferable that the particle size of the thermosetting resin powder 15A is 10 to 500 μm. It is preferable that the amount of thermosetting resin powder 15A is adjusted so that the VF value (%) of the molded body reaches 40 to 70%. The VF value (%) is a value calculated by (total weight of fiber substrates / fiber density) / (volume of molded body) × 100.

[0152] Thermosetting resin powder 15A is disposed between the fiber substrates 11B and 11C and laminated to form a laminate of fiber substrates 11A to 11D. This laminate of fiber substrates 11A to 11D is then clamped between the lower mold 31 and upper mold 32 of a heated mold 30 for heating and compression. The mold 30 is heated to a temperature Tc℃, where the thermosetting resin powder 15A can melt and solidify, by a heating unit such as an electric heater.

[0153] In the relationship between the temperature Tc℃ of the mold 30 and the melting start temperature Ta℃ and curing reaction start temperature Tb℃ of the thermosetting resin, it is preferably set to [Tb+(Tb-Ta) / 3]-15≤Tc≤[Tb+(Tb-Ta) / 3]+20, and more preferably set to [Tb+(Tb-Ta) / 3]-10≤Tc≤[Tb+(Tb-Ta) / 3]+20. For example, when Ta℃=70℃ and Tb℃=130℃, Tc℃ is 140℃~170℃.

[0154] In order to ensure that the thermosetting resin powder 15A between the fiber substrates can be well impregnated in the fiber substrates 11A to 11D after melting, the pressure (compression) of the fiber substrates 11A to 11D during heating and compression by the mold 30 is preferably 2 to 20 MPa.

[0155] In addition, the compression rate (%) of the fiber substrates 11A to 11D is a value calculated by (the interval between the die surface of the lower die 31 and the die surface of the upper die 32) / (the total thickness of all layers of the fiber substrate) × 100, and is preferably 60 to 100%.

[0156] By heating the laminated body using mold 30, the thermosetting resin powder 15A between the fiber substrates (between fiber substrate 11B and fiber substrate 11C) melts. Furthermore, the molten thermosetting resin is impregnated into the lower fiber substrates 11B and 11A and the upper fiber substrates 11C and 11D by compression of the laminated body. Then, the thermosetting resin impregnated in the fiber substrates 11A to 11D solidifies, thereby integrating the fiber substrates 11A to 11D under compressed conditions, resulting in a mold surface shape shaped like the lower mold 31 and the upper mold 32. Figure 1 Fiber-reinforced resin molded body 10.

[0157] Figure 3 An embodiment is shown in which six fiber substrates 11A to 11F are stacked, and thermosetting resin powder 15A to 15E is disposed between the fiber substrates and then heated and compressed by a mold 30.

[0158] The amount (total) of thermosetting resin powder 15A, the heating temperature of mold 30, the pressure of the laminate, etc. Figure 2 As described in the implementation method.

[0159] <Example>

[0160] use Figure 4 The fiber-reinforced resin molded articles of Examples 1A to 7A and Comparative Examples 1A and 2A were prepared using the thermosetting resin shown below. Furthermore, the viscosity of the thermosetting resin was measured using a Rheosol-G3000 rheometer manufactured by UBM Corporation under the following conditions.

[0161] 1) Take 0.4g of the sample and form it into granules (approximately φ18mm in diameter and 0.4mm in thickness). Clamp the formed granules onto a parallel plate with a diameter of φ18mm.

[0162] 2) Under the conditions of heating rate of 5℃ / min, frequency of 1Hz, rotation angle (strain) of 0.1deg and constant heating rate, the dynamic viscosity was measured at 2℃ intervals between 40℃ and 200℃.

[0163] Preparation of Example 1A

[0164] As the fiber substrate, prepare 4 sheets of carbon fiber fabric (manufactured by Teijin Corporation, product name: W-3101, unit weight: 200g / m²). 2 The substrate (0.22mm thick) is cut into 250×200mm pieces. Each piece of fiber substrate weighs 10g after cutting. Two pieces of fiber substrate are stacked, and 25g of resin A1 is evenly distributed on top as a thermosetting resin powder. The remaining two pieces of fiber substrate are then stacked on top to create the pre-molding laminate.

[0165] Resin A1 is a phenolic resin manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50252. The average particle size is 30μm, the melting start temperature Ta℃ is 69℃, the curing reaction start temperature Tb℃ is 135℃, (Tb-Ta) is 66℃, the lowest viscosity (the lowest viscosity at temperatures above the melting start temperature Ta℃) is 59Pa·s, the highest viscosity (the highest viscosity in the temperature range of curing reaction start temperature Tb℃ to 190℃) is 8768Pa·s, the (Tb-Ta) / 3 value is 22℃, and the Tb+(Tb-Ta) / 3 value is 157℃.

[0166] Figure 6 The graphs show the viscosity measurement results of resin A1 (Examples 1A, 2A, 3A).

[0167] The pre-molding laminate is placed on the molding surface (mold surface) of the lower mold of a mold heated to 150°C. The upper mold of the mold is then placed over the pre-molding laminate, and the mold is closed. The laminate is then heated and compressed at a pressure of 5 MPa and 150°C for 10 minutes. The thermosetting resin powder disposed between the central fiber substrates melts due to heating, and the pre-molding laminate is compressed, thereby impregnating the fiber substrates in each layer. Curing is completed in this state, thus producing the fiber-reinforced resin molded body of Example 1A, which is a laminated monolithic body composed of thermosetting resin impregnated in four layers of fiber substrates and cured therein.

[0168] Preparation of Example 2A

[0169] Using the same four fiber substrates and resin A1 as in Example 1A, 8.3g of resin A1 was disposed approximately uniformly between each fiber substrate (the total amount of resin A1 between all fiber substrates was 24.9g) to prepare a pre-molding laminate. Otherwise, the fiber-reinforced resin molded body of Example 2A was prepared by heating and compressing under the same conditions as in Example 1A.

[0170] Preparation of Example 3A

[0171] Using 10 sheets of the same fiber substrate as in Example 1A, 5 sheets of the fiber substrate were stacked, 60g of resin A was disposed on them in a substantially uniform manner, and the remaining 5 sheets of fiber substrate were stacked on them to produce a pre-molding laminate. Otherwise, the fiber-reinforced resin molded body of Example 3A was produced by heating and compressing under the same conditions as in Example 1A.

[0172] Preparation of Example 4A

[0173] Except that resin B1 was used as the thermosetting resin, the fiber-reinforced resin molded body of Example 4A was made in the same manner as in Example 1A.

[0174] Resin B1 is a phenolic resin manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-310. It has an average particle size of 30μm, a melt start temperature (Ta℃) of 95℃, a curing reaction start temperature (Tb℃) of 135℃, a (Tb-Ta) ratio of 40℃, a minimum viscosity (the lowest viscosity at temperatures above the melt start temperature (Ta℃)) of 1500 Pa·s, a maximum viscosity (the highest viscosity in the temperature range from the curing reaction start temperature (Tb℃) to 190℃) of 209004 Pa·s, a (Tb-Ta) / 3 value of 13℃, and a Tb+(Tb-Ta) / 3 value of 148℃.

[0175] Preparation of Example 5A

[0176] Except that 25g of resin (in which 12.5g of resin A1 and 12.5g of resin C1 are uniformly mixed) is used as the thermosetting resin and the mold temperature is set to 170°C, the fiber-reinforced resin molded body of Example 5A is made in the same manner as in Example 1A.

[0177] Resin C1 is made by pulverizing epoxy resin manufactured by Mitsubishi Chemical Corporation, product name: J-ER-1001, using a mortar and pestle. The average particle size is 100 μm.

[0178] The resin prepared by uniformly mixing 12.5g of resin A1 and 12.5g of resin C1 has a melting start temperature Ta℃ of 73℃, a curing reaction start temperature Tb℃ of 140℃, (Tb-Ta) of 67℃, a minimum viscosity (the lowest viscosity at temperatures above the melting start temperature Ta℃) of 22 Pa·s, a maximum viscosity (the highest viscosity in the temperature range from the curing reaction start temperature Tb℃ to 190℃) of 5180 Pa·s, a (Tb-Ta) / 3 value of 22℃, and a Tb+(Tb-Ta) / 3 value of 162℃.

[0179] Preparation of Example 6A

[0180] Except that 25g of resin (in which 12.5g of resin D1 and 12.5g of resin E1 are uniformly mixed) is used as the thermosetting resin and the mold temperature is set to 160°C, the fiber-reinforced resin molded body of Example 6A is made in the same manner as in Example 1A.

[0181] Resin D1 is made by pulverizing phenolic resin (product name: PR-50235D) manufactured by Sumitomo Bakelite Co., Ltd. using a mortar. The average particle size is 90 μm.

[0182] Resin E1 is made by pulverizing cyanate ester resin manufactured by Mitsubishi Gas Chemical Co., Ltd., under the product name CYTESTER TA, using a mortar. The average particle size is 100 μm.

[0183] The resin prepared by uniformly mixing 12.5g of resin D1 and 12.5g of resin E1 has a melting start temperature Ta℃ of 76℃, a curing reaction start temperature Tb℃ of 138℃, (Tb-Ta) of 62℃, a minimum viscosity (the lowest viscosity at temperatures above the melting start temperature Ta℃) of 475 Pa·s, a maximum viscosity (the highest viscosity in the temperature range from the curing reaction start temperature Tb℃ to 190℃) of 51895 Pa·s, a (Tb-Ta) / 3 value of 21℃, and a Tb+(Tb-Ta) / 3 value of 159℃.

[0184] Preparation of Example 7A

[0185] Except that 24.9g of resin (a uniform mixture of 8.3g resin D1, 8.3g resin E1 and 8.3g resin C1) was used as the thermosetting resin and the mold temperature was set to 170°C, the fiber-reinforced resin molded body of Example 7A was made in the same manner as in Example 1A.

[0186] The resin prepared by uniformly mixing 8.3g of resin D1, 8.3g of resin E1, and 8.3g of resin C1 has a melting start temperature Ta℃ of 75℃, a curing reaction start temperature Tb℃ of 139℃, a (Tb-Ta) ratio of 64℃, a minimum viscosity (the lowest viscosity at temperatures above the melting start temperature Ta℃) of 575 Pa·s, a maximum viscosity (the highest viscosity in the temperature range from the curing reaction start temperature Tb℃ to 190℃) of 19025 Pa·s, a (Tb-Ta) / 3 value of 21℃, and a Tb+(Tb-Ta) / 3 value of 160℃.

[0187] Production of Comparative Example 1A

[0188] Except that resin F1 was used as the thermosetting resin and the mold temperature was set to 100°C, the fiber-reinforced resin molded body of Comparative Example 1A was made in the same manner as in Example 1A.

[0189] Resin F1 is a phenolic resin manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50699. The average particle size is 30μm, the melting start temperature Ta℃ is 72℃, the curing reaction start temperature Tb℃ is 91℃, (Tb-Ta) is 19℃, the lowest viscosity (the lowest viscosity at temperatures above the melting start temperature Ta℃) is 118908Pa·s, the highest viscosity (the highest viscosity in the temperature range from the curing reaction start temperature Tb℃ to 190℃) is 164468Pa·s, the (Tb-Ta) / 3 value is 6℃, and the Tb+(Tb-Ta) / 3 value is 97℃.

[0190] Figure 6 The graph shows the viscosity measurement results of resin F1 (Comparative Example 1A).

[0191] The resin F1 used in Comparative Example 1A has a high minimum and maximum viscosity. Resin F1 has poor impregnation properties on the fiber substrate (carbon fiber fabric), and it is impossible to obtain a molded body with uniform impregnation of thermosetting resin.

[0192] Production of Comparative Example 2A

[0193] Except that the resin (24.9g) obtained by uniformly mixing 8.3g of resin A1 and 16.6g of resin D1 was used as the thermosetting resin and the mold temperature was set to 160°C, the fiber-reinforced resin molded body of Comparative Example 2A was prepared in the same manner as in Example 1A.

[0194] The resin prepared by uniformly mixing 8.3g of resin A1 and 16.6g of resin D1 has a melting start temperature Ta℃ of 80℃, a curing reaction start temperature Tb℃ of 140℃, (Tb-Ta) of 60℃, a minimum viscosity (the lowest viscosity at temperatures above the melting start temperature Ta℃) of 21 Pa·s, a maximum viscosity (the highest viscosity in the temperature range from the curing reaction start temperature Tb℃ to 190℃) of 260 Pa·s, a (Tb-Ta) / 3 value of 20℃, and a Tb+(Tb-Ta) / 3 value of 160℃.

[0195] Figure 6 The graph shows the viscosity measurement results for resin A1 / resin D1 = 1 / 2 (Comparative Example 2A).

[0196] In Comparative Example 2A, the thermosetting resin was not cured sufficiently, and the molded body deformed during demolding, resulting in an inability to obtain a good molded body.

[0197] The fiber-reinforced resin molded articles of Examples 1A to 7A and Comparative Examples 1A and 2A were subjected to measurement of thickness (mm), VF value (%), flexural strength (MPa), flexural modulus (GPa), and appearance assessment. The results are as follows: Figure 5 As shown, and explained below.

[0198] The VF value (%) is calculated as (total weight of fiber substrate / fiber density) / (volume of molded body) × 100.

[0199] The flexural strength (MPa) and flexural modulus (GPa) were determined according to JIS K7074 A method.

[0200] The appearance is judged by visually confirming whether there are any defects on the surface of the molded body caused by deformation or uneven resin impregnation. The condition without defects is rated as "○" and the condition with defects is rated as "×".

[0201] Physical properties of Example 1A, etc.

[0202] The fiber-reinforced resin molded body of Example 1A is made by setting the number of fiber substrate layers to 4, setting the thermosetting resin to resin A1, and placing thermosetting resin powder between the central fiber substrate layers. The thickness of the molded body is 0.8 mm, the VF value is 58%, the flexural strength is 550 MPa, the flexural modulus is 54 GPa, the appearance of the molded body is "○", and it has high strength and rigidity and good appearance.

[0203] Physical properties of Example 2A, etc.

[0204] The fiber-reinforced resin molded body of Example 2A is made by stacking 4 fiber substrates, using resin A1 as the thermosetting resin, and distributing thermosetting resin powder between each fiber substrate. The molded body has a thickness of 0.8 mm, a VF value of 58%, a flexural strength of 600 MPa, a flexural modulus of 55 GPa, and an appearance of "○". Because it is made by distributing thermosetting resin powder between each fiber substrate, its strength and rigidity are higher than those of Example 1A.

[0205] Physical properties of Example 3A, etc.

[0206] The fiber-reinforced resin molded body of Example 3A is made by setting the number of fiber substrate layers to 10, setting the thermosetting resin to resin A1, and placing thermosetting resin powder between the central fiber substrate layers. The thickness of the molded body is 2.0 mm, the VF value is 59%, the flexural strength is 620 MPa, the flexural modulus is 53 GPa, the appearance of the molded body is "○", and it has high strength and rigidity and good appearance.

[0207] Physical properties of Example 4A, etc.

[0208] The fiber-reinforced resin molded body of Example 4A is made by stacking four fiber substrate layers, using resin B1 as the thermosetting resin, and distributing thermosetting resin powder between the central fiber substrate layers. The molded body has a thickness of 0.8 mm, a VF value of 55%, a flexural strength of 450 MPa, a flexural modulus of elasticity of 45 GPa, and an "○" appearance. It exhibits high strength and rigidity, and a good appearance. Furthermore, Example 4A using resin B1 has lower strength and rigidity than Example 1A using resin A1.

[0209] Physical properties of Example 5A, etc.

[0210] The fiber-reinforced resin molded body of Example 5A was made by stacking four fiber substrates, using a thermosetting resin ratio of resin A1 / resin C1 of 1:1, and placing thermosetting resin powder between the central fiber substrates. The molded body had a thickness of 0.8 mm, a VF value of 57%, a flexural strength of 990 MPa, a flexural modulus of 60 GPa, and an "○" appearance. It exhibited high strength and rigidity, and a good appearance. Furthermore, Example 5A, using a mixed resin with a resin ratio of A1 / C1 of 1:1, showed higher strength and rigidity than Example 1A, which used resin A1, and Example 4A, which used resin B1.

[0211] Physical properties of Example 6A, etc.

[0212] The fiber-reinforced resin molded body of Example 6A is made by stacking four fiber substrates, using a thermosetting resin ratio of resin D1 / resin E1 = 1 / 1, and placing thermosetting resin powder between the central fiber substrates. The molded body has a thickness of 0.8 mm, a VF value of 59%, a flexural strength of 900 MPa, a flexural modulus of elasticity of 61 GPa, and an "○" appearance. It exhibits high strength and rigidity, and a good appearance. Furthermore, Example 6A, using a mixed resin with resin D1 / resin E1 = 1 / 1, has the same high strength and rigidity as Example 5A, which uses a mixed resin with resin A1 / resin C1 = 1 / 1.

[0213] Physical properties of Example 7A, etc.

[0214] The fiber-reinforced resin molded body of Example 7A is made by stacking four fiber substrates, using a thermosetting resin ratio of resin D1 / resin E1 / resin C1 = 1 / 1 / 1, and placing thermosetting resin powder between the central fiber substrates. The molded body has a thickness of 0.8 mm, a VF value of 58%, a flexural strength of 930 MPa, a flexural modulus of elasticity of 58 GPa, and an appearance of "○". It exhibits high strength and rigidity, and a good appearance. Furthermore, Example 7A, using a mixed resin of resin D1 / resin E1 / resin C1 = 1 / 1 / 1, has the same high strength and rigidity as Example 5A, which uses a mixed resin of resin A1 / resin C1 = 1 / 1, and Example 6A, which uses a mixed resin of resin D1 / resin E1 = 1 / 1.

[0215] Comparative Example 1A's physical properties, etc.

[0216] Comparative Example 1A's fiber-reinforced resin molded body is made by setting the number of fiber substrate layers to 4, setting the thermosetting resin to resin F1, and placing thermosetting resin powder between the central fiber substrate layers. However, the impregnation of resin F1 is poor, and it is impossible to obtain a molded body with uniform thermosetting resin impregnation. Therefore, it is impossible to measure the thickness, VF value, flexural strength, and flexural modulus.

[0217] Comparative Example 2A's physical properties, etc.

[0218] Comparative Example 2A's fiber-reinforced resin molded body was made by setting the number of fiber substrate layers to 4, setting the thermosetting resin to resin A1 / resin D1 = 1 / 2, and placing thermosetting resin powder between the central fiber substrate layers. However, the thermosetting resin was not fully cured, and the molded body deformed during demolding. Therefore, it was impossible to measure the thickness, VF value, flexural strength, and flexural modulus.

[0219] Furthermore, in the embodiments, only a flat shape is shown as the shape of the fiber-reinforced resin molded body. However, in the present invention, the shape (mold shape) of the fiber-reinforced resin molded body is not limited to a flat shape and can be set to any shape such as a curved surface or a concave-convex shape.

[0220] Thus, according to this configuration, fiber-reinforced resin molded articles can be obtained simply, inexpensively, and safely without concern for environmental pollution, without the need for prepregs.

[0221] <Second Form>

[0222] The implementation method of the second form will be described.

[0223] Figure 7 The fiber-reinforced resin prepreg 110 of the first embodiment shown in (1-1) is formed by heating and compressing the fiber substrate 111 and the thermosetting resin 115 together, resulting in a state in which the thermosetting resin 115 is attached to the fiber substrate 111. The thermosetting resin 115 attached to the fiber substrate 111 is in a solid state before the curing reaction begins.

[0224] The prepreg 110 in the first embodiment includes a single layer of fiber substrate 111, but the prepreg may also be composed of multiple layers of fiber substrate 111. The fiber substrate 111 can be a fabric or nonwoven fabric made of glass fiber, polyaramid fiber, basalt fiber, carbon fiber, etc., and is not particularly limited. Carbon fiber fabric is preferred due to its excellent lightweight and high rigidity. As for the carbon fiber fabric, fabrics woven in a way that involves weaving fibers in more than one direction are preferred; for example, plain weave fabrics, twill weave fabrics, satin weave fabrics, and triaxial fabrics made of yarns in three directions are preferred. Furthermore, from the viewpoint of impregnation with the thermosetting resin 115 and the rigidity of the fiber-reinforced resin molded body, a fiber weight of 50 to 600 g / m² is preferred for the carbon fiber fabric. 2 .

[0225] When manufacturing the prepreg 110, the thermosetting resin 115 is a solid powder resin that is not heated and compressed. The shape of the powder can be spherical, needle-like, fragmented, etc., and there is no particular limitation.

[0226] When the prepreg 110 is made, the powder of thermosetting resin 115 is configured to contact the fiber substrate 111. When the fiber substrate 111 and the powder of thermosetting resin 115 are heated and compressed together, they melt and are impregnated in the fiber substrate 111. The prepreg is then cooled and cured in the state before the curing reaction begins.

[0227] The viscosity of thermosetting resin 115 at the curing reaction start temperature Tb℃ is 2000 Pa·s or less, preferably 1500 Pa·s or less.

[0228] By using prepreg 110 to manufacture fiber-reinforced resin molded articles with a viscosity of less than 2000 Pa·s at the curing reaction start temperature Tb℃, the thermosetting resin 115 can be uniformly impregnated in the fiber substrate 111, resulting in a high-quality fiber-reinforced resin molded article.

[0229] The thermosetting resin 115 has a maximum viscosity of 1000 Pa·s or higher in the range of curing reaction start temperature Tb℃~190℃.

[0230] With a maximum viscosity of 1000 Pa·s or more within the range of curing reaction start temperature Tb℃~190℃, when using prepreg 110 to manufacture fiber-reinforced resin molded articles, the molten thermosetting resin 115 can be impregnated in the fiber substrate 111 and fully cured. The fiber-reinforced resin molded articles have good shapeability and can obtain sufficient strength in a short time (about 10 minutes).

[0231] The preferred melting start temperature Ta of the thermosetting resin 115 is 60 to 100°C. By using a melting start temperature Ta within the above range, the heating temperature during the production of the prepreg 110 does not need to be so high, making the production of the prepreg 110 easier.

[0232] Regarding the melt start temperature Ta℃ and the curing reaction start temperature Tb℃ of the thermosetting resin 115, it is preferable that 30≤(Tb-Ta)≤100, and more preferably 40≤(Tb-Ta)≤70. By setting (Tb-Ta) within this range, when manufacturing fiber-reinforced resin molded articles using prepreg 110, the thermosetting resin 115 can be sufficiently impregnated in the fiber substrate 111, and a fiber-reinforced resin molded article with uniform physical properties can be obtained.

[0233] Compared to the temperature Tc℃ during heating and compression when making prepreg 110, it is preferable that the melting start temperature Ta℃ of the thermosetting resin 115 is below Tc℃, and the curing reaction start temperature Tb℃ is above Tc℃. More preferably, Ta℃ is below Tc℃-5℃, and Tb℃ is above Tc℃+5℃. By setting Ta℃ and Tb℃ within this range, the thermosetting resin 115 can melt and impregnate the fiber substrate 111 when making prepreg 110. In addition, the curing reaction of the thermosetting resin 115 has not started when making prepreg 110, so the quality of prepreg 110 is good, and the storage stability of prepreg 110 is improved.

[0234] From the viewpoint of easy melting, it is preferable that the particle size of the thermosetting resin 115 powder used in the preparation of the prepreg 110 is 10 to 500 μm. It is preferable that the amount of thermosetting resin 115 used in the preparation of the prepreg is adjusted so that the VF value (%) of the fiber-reinforced resin molded body reaches 40 to 70%. The VF value (%) is a value calculated by (total weight of fiber substrate / density of fiber) / (volume of fiber-reinforced resin molded body) × 100.

[0235] As a thermosetting resin that satisfies the above-mentioned melt start temperature Ta℃, curing reaction start temperature Tb℃, (Tb-Ta) range, lowest viscosity, and highest viscosity, a resin selected from the group consisting of phenolic resin, a mixture of phenolic resin and epoxy resin, a mixture of phenolic resin and cyanate ester resin, and a mixture of phenolic resin, cyanate ester resin, and epoxy resin. Phenolic resins, due to their excellent flame retardancy, can impart excellent strength and flame retardancy to fiber-reinforced resin molded articles.

[0236] In addition, various powder additives such as pigments, antibacterial agents, and ultraviolet absorbers can be added to the thermosetting resin 115 within a range that does not affect the viscosity or reactivity of the thermosetting resin.

[0237] The fiber-reinforced resin molding prepreg 110 of the first embodiment is shown in one form. Furthermore, in the following description, there are instances where "thermosetting resin 115 powder" is indicated by a combination of the numeral "115" and the letter "a".

[0238] like Figure 7 As shown in (1-2), the fiber substrate 111 and the thermosetting resin powder 115A disposed in contact with the fiber substrate 111 are clamped by the demolding plastic films 141A and 141B, and the above structure is clamped and heated and compressed by the lower mold 151 and upper mold 152 of the heated mold 150, thereby producing the prepreg 110 of the first embodiment. At this time, the thermosetting resin powder 115A is disposed on one or both of the upper and lower surfaces of the fiber substrate 111.

[0239] The mold 150 is heated by a heating unit such as an electric heater. The temperature (mold temperature) Tc℃ during heating and compression when making the prepreg 110 is above the melting start temperature Ta℃ of the thermosetting resin powder 115A (the aforementioned thermosetting resin 115) and below the curing reaction start temperature Tb℃. More preferably, the temperature (mold temperature) Tc℃ during heating and compression is above the melting start temperature Ta℃ + 5℃ of the thermosetting resin 115 and below the curing reaction start temperature Tb℃ - 5℃.

[0240] In order for the thermosetting resin powder 115A to be well impregnated into the fiber substrate 111 after melting, it is preferable that the pressure (compression) applied by the mold 150 during the preparation of the prepreg is 0.1 to 10 MPa.

[0241] In addition, the compression rate (%) of the fiber substrate 111 is a value calculated by (the gap between the die surface of the lower die 151 and the die surface of the upper die 152 - the total thickness of the release film) / (the total thickness of all layers of the fiber substrate) × 100, preferably 60 to 100%.

[0242] The thermosetting resin powder 115A melts due to heating and compression and is impregnated in the fiber substrate 111, and is cooled and cured in the state before the curing reaction begins.

[0243] Furthermore, the method of producing prepreg is not limited to the method of using molds mentioned above. Other methods include the hot roller method of heating and compressing by hot rollers, the double-layer belt method of heating and compressing between the upper and lower belts, and so on.

[0244] The second embodiment will be described. In the following description, in order to facilitate understanding of the vertical positional relationship of the multiple fiber substrates 111, the fiber substrates are represented by reference numerals "111" and "letters" such as "111A".

[0245] Figure 8 The fiber-reinforced resin molding prepreg 120 of the second embodiment shown in (2-1) includes four layers of fiber substrates 111A, 111B, 111C, 111D and a thermosetting resin 115, wherein the thermosetting resin 115 is attached to the fiber substrates 111A to 111D. Furthermore, the fiber substrates 111A to 111D and the thermosetting resin 115 are as described in the prepreg 110 of the first embodiment.

[0246] Regarding the fiber-reinforced resin molding prepreg 120 of the second embodiment, one form of its fabrication is shown below.

[0247] like Figure 8 As shown in (2-2), a laminate consisting of thermosetting resin powder 115A sandwiched between two lower fiber substrates 111A and 111B and two upper fiber substrates 111C and 111D is clamped by release plastic films 141A and 141B. The structure is then clamped and heated and compressed by the lower mold 151 and upper mold 152 of a heated mold 150, thereby producing the fiber-reinforced resin molding prepreg 120 of the second embodiment. The heating and compression conditions are as described in the first embodiment. The thermosetting resin powder 115A melts due to heating and compression and impregnates the fiber substrates 111A to 111D, and is cooled and cured in a state before the curing reaction begins.

[0248] The third embodiment will be described. Figure 9 The fiber-reinforced resin molding prepreg 130 of the third embodiment shown in (3-1) includes, similarly to the second embodiment, four layers of fiber substrates 111A, 111B, 111C, 111D and thermosetting resin 115, wherein the thermosetting resin 115 is attached to the fiber substrates 111A to 111D. In the third embodiment, the powder of the thermosetting resin 115 used to make the prepreg 130 is configured as shown below, and has a different morphology than that of the second embodiment.

[0249] The following shows one form of the fabrication of the fiber-reinforced resin molding prepreg 130 according to the third embodiment.

[0250] like Figure 9 As shown in (3-2), a laminate consisting of thermosetting resin powders 115A, 115B, and 115C sandwiched between the four fiber substrates 111A to 111D (between layers) is held in place by release plastic films 141A and 141B. The structure is then held in place by the lower mold 151 and upper mold 152 of a heated mold 150 and subjected to heating and compression, thereby producing the fiber-reinforced resin molding prepreg 130 of the third embodiment. The heating and compression conditions are as described in the first embodiment. The thermosetting resin powders 115A to 115C melt due to heating and compression and impregnate the fiber substrates 111A to 111D, and are cooled and cured in a state before the curing reaction begins.

[0251] The method for manufacturing fiber-reinforced resin molded articles using the fiber-reinforced resin molding prepreg of this disclosure is carried out by heating and compressing the fiber-reinforced resin molding prepreg, which includes a single layer or multiple layers of fiber substrate 111, through a shaping mold, thereby causing the thermosetting resin 115 to react and cure. The shape of the mold surface is not limited to a plane, and can be set as concave-convex, curved, etc., depending on the product.

[0252] In the relationship between the heating temperature (temperature of the mold used for shaping) Td℃ during the manufacture of fiber-reinforced resin molded articles and the melt start temperature Ta℃ and curing reaction start temperature Tb℃ of thermosetting resin 115,

[0253] The preferred setting is [Tb+(Tb-Ta) / 3]-15≤Td≤[Tb+(Tb-Ta) / 3]+20.

[0254] More preferably, it is set as [Tb+(Tb-Ta) / 3]-10≤Td≤[Tb+(Tb-Ta) / 3]+20. For example, when Ta℃=70℃ and Tb℃=130℃, Td℃ is 140℃~170℃.

[0255] In order for the thermosetting resin 115 to be well impregnated into the fiber substrate 111 after melting, it is preferable that the pressure (compression) of the fiber-reinforced resin molding prepreg during the heating and compression by the shaping mold is 2 to 20 MPa.

[0256] Furthermore, the compression ratio (%) of the fiber-reinforced resin molding prepreg during heating and compression by the shaping mold is a value calculated by (the distance between the mold surface of the lower mold 151 and the mold surface of the upper mold 152) / (the thickness of the prepreg) × 100, preferably 60 to 100%.

[0257] By heating and compressing the fiber-reinforced resin prepreg using a shaping mold, the thermosetting resin 115 of the prepreg melts. Furthermore, by reacting and curing the molten thermosetting resin 115, a fiber-reinforced resin molded body shaped into the mold surface shape of the lower and upper molds can be obtained.

[0258] <Example>

[0259] use Figure 10 The powder of the thermosetting resin shown was used to prepare fiber-reinforced resin molding prepregs for Examples 1B to 7B and Comparative Examples 1B and 2B. Fiber-reinforced resin molded articles were then made using the freshly prepared prepregs. The viscosity of the thermosetting resin was measured under the following conditions using a Rheosol-G3000 rheometer manufactured by UBM Corporation.

[0260] 1) Take 0.4g of the sample and form it into granules (approximately φ18mm in diameter and 0.4mm in thickness). Clamp the formed granules onto a parallel plate with a diameter of φ18mm.

[0261] 2) Under the conditions of heating rate of 5℃ / min, frequency of 1Hz, rotation angle (strain) of 0.1deg and constant heating rate, the dynamic viscosity was measured at 2℃ intervals between 40℃ and 200℃.

[0262] <Example 1B>

[0263] Prepreg production

[0264] Example 1B as follows Figure 7 Examples (1-1) and (1-2) show a prepreg where the fiber substrate is a single sheet (single layer). As the fiber substrate, carbon fiber fabric (manufactured by Teijin Corporation, product name: W-3101, unit weight: 200g / m²) is prepared. 2The substrate (0.22mm thick) is cut into 250mm × 200mm pieces. Each piece of fiber substrate weighs 10g after cutting. The prepared fiber substrate is placed on a PET film (release film) that has been treated with a release agent. 7g of the following resin A2 powder, which is a thermosetting resin powder, is roughly evenly distributed on the fiber substrate. The PET film that has been treated with a release agent is then placed on top to form a prepreg pre-molding laminate.

[0265] Resin A2 is a phenolic resin manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50252, with an average particle size of 30μm.

[0266] Figure 11 The graphs show the viscosity measurement results of resin A2 (Examples 1B, 2B, 3B).

[0267] The prepreg pre-molded laminate was placed on the molding surface (mold surface) of the lower mold of a mold heated to 100°C. The upper mold of the mold was then placed over the prepreg pre-molded laminate, and the mold was closed. Heating and compression were performed at a pressure of 0.1 MPa for 5 minutes. This melted the resin A2 powder on the fiber substrate, allowing it to molten and impregnate the fiber substrate. The mold was then opened, and the laminate, along with the PET film, was removed. After natural cooling to room temperature, the PET film was removed, yielding the prepreg of Example 1B.

[0268] Fabrication of fiber-reinforced resin molded articles

[0269] The laminate formed by overlapping four layers of the prepreg of Example 1B is placed on the molding surface (mold surface) of the lower mold of a mold that has been preheated to 150°C. The upper mold of the mold is covered onto the laminate and the mold is closed. The laminate is heated and compressed at a pressure of 5 MPa for 10 minutes to allow resin A2 to react and cure. After that, the mold is opened and the fiber-reinforced resin molded body of Example 1B is taken out.

[0270] <Example 2B>

[0271] Prepreg production

[0272] Example 2B Figure 8 As shown in (2-1) and (2-2) in the figure, the fiber substrate of the prepreg is an example of 4 sheets (4 layers). Except that 4 sheets of fiber substrate and resin A2 are used as in Example 1B, and 28g of resin A2 is disposed approximately uniformly in the middle of the 4 sheets of fiber substrate, the prepreg of Example 2B is made in the same manner as in Example 1B.

[0273] Fabrication of fiber-reinforced resin molded articles

[0274] The prepreg of Example 2B was placed on the molding surface (mold surface) of the lower mold of a mold that had been preheated to 150°C. The upper mold of the mold was covered onto the laminate and the mold was closed. The mold was heated and compressed at a pressure of 5 MPa for 10 minutes to allow resin A2 to react and cure. After that, the mold was opened and the fiber-reinforced resin molded body of Example 2B was taken out.

[0275] <Example 3B>

[0276] Prepreg production

[0277] Example 3B Figure 9 As shown in (3-1) and (3-2), a prepreg is made by distributing resin A2 between the layers of four fiber substrates. The prepreg of Example 3B is made in the same manner as Example 1B, except that 9.3g of resin A2 is distributed substantially uniformly between the layers of four fiber substrates, the same as in Example 1B.

[0278] Fabrication of fiber-reinforced resin molded articles

[0279] The prepreg of Example 3B was placed on the molding surface (mold surface) of the lower mold of a mold that had been preheated to 150°C. The upper mold of the mold was covered onto the laminate and the mold was closed. The mold was heated and compressed at a pressure of 5 MPa for 10 minutes to allow resin A2 to react and cure. After that, the mold was opened and the fiber-reinforced resin molded body of Example 3B was taken out.

[0280] <Example 4B>

[0281] Prepreg production

[0282] Example 4B is an example where the fiber substrate of the prepreg is a single sheet. The prepreg of Example 4B is prepared in the same manner as in Example 1B, except that resin B2 is used as the powder of the thermosetting resin.

[0283] Resin B2 is a phenolic resin manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-310, with an average particle size of 30μm.

[0284] Fabrication of fiber-reinforced resin molded articles

[0285] The fiber-reinforced resin molded body of Example 4B was made using four pieces of the prepreg of Example 4B in the same manner as Example 1B.

[0286] <Example 5B>

[0287] Prepreg production

[0288] Example 5B is an example where the fiber substrate of the prepreg is one sheet. Except that 7g of resin, which is a powder of thermosetting resin, is used to uniformly mix resin A2 and resin C2 in a weight ratio of 1:1, the prepreg of Example 5B is made in the same manner as in Example 1B.

[0289] Resin C2 is made by pulverizing epoxy resin manufactured by Mitsubishi Chemical Corporation, product name: jER-1001, using a mortar and pestle, with an average particle size of 100μm.

[0290] Fabrication of fiber-reinforced resin molded articles

[0291] Except for using 4 pieces of the prepreg from Example 5B and setting the mold temperature to 170°C, the fiber-reinforced resin molded body of Example 5B was made in the same manner as in Example 1B.

[0292] <Example 6B>

[0293] Prepreg production

[0294] Example 6B is an example where the fiber substrate of the prepreg is one sheet. Except that 7g of resin powder, which is a uniform mixture of resin D2 and resin E2 in a 1:1 weight ratio, is used as the thermosetting resin powder, the prepreg of Example 6B is prepared in the same manner as in Example 1B.

[0295] Resin D2 is used by pulverizing phenolic resin (product name: PR-50235D) manufactured by Sumitomo Bakelite Co., Ltd. using a mortar. The average particle size is 90 μm.

[0296] Resin E2 is produced by pulverizing cyanate ester resin manufactured by Mitsubishi Gas Chemical Co., Ltd., under the product name CYTESTER TA, using a mortar. The average particle size is 100 μm.

[0297] Fabrication of fiber-reinforced resin molded articles

[0298] Except for using 4 pieces of the prepreg from Example 6B and setting the mold temperature to 160°C, the fiber-reinforced resin molded body of Example 6B was made in the same manner as in Example 1B.

[0299] <Example 7B>

[0300] Prepreg production

[0301] Example 7B is an example where the fiber substrate of the prepreg is one sheet. Except that 7g of resin powder, which is a uniformly mixed resin D2, resin E2 and resin C2 in a weight ratio of 1:1:1, is used as the thermosetting resin powder, the prepreg of Example 7B is prepared in the same manner as in Example 1B.

[0302] Fabrication of fiber-reinforced resin molded articles

[0303] Except for using 4 pieces of the prepreg from Example 7B and setting the mold temperature to 170°C, the fiber-reinforced resin molded body of Example 7B was made in the same manner as in Example 1B.

[0304] <Comparative Example 1B>

[0305] Prepreg production

[0306] Except for using 7g of resin F2 as a thermosetting resin powder and setting the mold temperature to 80°C, the prepreg of Comparative Example 1 was prepared in the same manner as in Example 1B.

[0307] Resin F2 is a phenolic resin manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50699, with an average particle size of 30μm.

[0308] Figure 11 The graph shows the viscosity measurement results of resin F2 (Comparative Example 1B).

[0309] Fabrication of fiber-reinforced resin molded articles

[0310] Except for using 4 pieces of the prepreg from Comparative Example 1B and setting the mold temperature to 100°C, the fiber-reinforced resin molded body of Comparative Example 1B was made in the same manner as that of Example 1B.

[0311] The resin F2 used in Comparative Example 1B has a high minimum and maximum viscosity, and the resin F2 has poor impregnation in the fiber substrate (carbon fiber fabric), making it impossible to obtain a fiber-reinforced resin molded body with uniform impregnation of thermosetting resin.

[0312] <Comparative Example 2B>

[0313] Prepreg production

[0314] Using 7g of resin powder, which is a uniform mixture of resin A2 and resin D2 in a weight ratio of 1:2, Comparative Example 2B prepreg was prepared in the same manner as in Example 1B.

[0315] Figure 11 The graph shows the viscosity measurement results of the resin (Comparative Example 2B) in which resin A2 and resin D2 are uniformly mixed at a weight ratio of 1:2.

[0316] Fabrication of fiber-reinforced resin molded articles

[0317] The fiber-reinforced resin molded body of Comparative Example 2B was prepared using four pieces of prepreg from Comparative Example 2B in the same manner as that of Example 1B.

[0318] The resin used in Comparative Example 2B was not cured sufficiently, and it deformed during demolding of the fiber-reinforced resin molded article, resulting in an inability to obtain a good molded article.

[0319] The thickness (mm), VF value (%), flexural strength (MPa), and flexural modulus (GPa) of the fiber-reinforced resin molded articles of Examples 1B-7B and Comparative Examples 1B and 2B were measured, and their appearance was judged. The results are as follows: Figure 12 As shown, and explained below.

[0320] The flexural strength (MPa) and flexural modulus (GPa) were determined according to JIS K7074 A method.

[0321] The appearance is judged by visually confirming whether there are any defects on the surface of the molded body, such as deformation or uneven resin impregnation. The condition without defects is rated as "○", and the condition with defects is rated as "×".

[0322] Physical properties of the fiber-reinforced resin molded article of Example 1B

[0323] The fiber-reinforced resin molded body of Example 1B is made by stacking four sheets of the prepreg of Example 1B. The prepreg of Example 1B is made by using resin A2 as the thermosetting resin powder and one sheet as the fiber substrate. The molded body of Example 1B has a thickness of 0.8 mm, a VF value of 58%, a flexural strength of 610 MPa, a flexural modulus of elasticity of 52 GPa, and an appearance of "○". It has high strength and rigidity (flexural modulus of elasticity) and a good appearance.

[0324] Properties of the fiber-reinforced resin molded article of Example 2B

[0325] The fiber-reinforced resin molded body of Example 2B was made from the prepreg of Example 2B, which was made by placing resin A2 in the middle of four fiber substrates. The molded body of Example 2B had a thickness of 0.8 mm, a VF value of 58%, a flexural strength of 600 MPa, a flexural modulus of elasticity of 53 GPa, and an appearance of "○". It had high strength and rigidity and a good appearance.

[0326] Physical properties of the fiber-reinforced resin molded article of Example 3B

[0327] The fiber-reinforced resin molded body of Example 3B was made from the prepreg of Example 3B, which was made by distributing resin A2 between each layer of four fiber substrates. The molded body of Example 3B had a thickness of 0.8 mm, a VF value of 58%, a flexural strength of 620 MPa, a flexural modulus of elasticity of 53 GPa, and an appearance of "○". It exhibited high strength and rigidity, and a good appearance.

[0328] Physical properties of the fiber-reinforced resin molded article of Example 4B

[0329] The fiber-reinforced resin molded body of Example 4B was made by stacking four sheets of the prepreg from Example 4B. The prepreg of Example 4B was made by using resin B2 as the thermosetting resin powder and one sheet of fiber substrate. The molded body of Example 4B had a thickness of 0.8 mm, a VF value of 55%, a flexural strength of 460 MPa, a flexural modulus of elasticity of 46 GPa, and an "○" appearance. It exhibited high strength and rigidity, and a good appearance. The strength and rigidity of Example 4B using resin B2 were lower than those of Example 1B using resin A2.

[0330] Physical properties of the fiber-reinforced resin molded article of Example 5B

[0331] The fiber-reinforced resin molded body of Example 5B was made by stacking four sheets of the prepreg of Example 5B. The prepreg of Example 5B was made by setting the thermosetting resin powder as resin A2 / resin C2 = 1 / 1 and the fiber substrate as one sheet. The molded body of Example 5B had a thickness of 0.8 mm, a VF value of 57%, a flexural strength of 980 MPa, a flexural modulus of elasticity of 60 GPa, and an appearance of "○". It had high strength and rigidity and a good appearance. In addition, the strength and rigidity of Example 5B, which used a mixed resin of resin A2 / resin C2 = 1 / 1, were higher than those of Example 1B, which used resin A2, and Example 4B, which used resin B2.

[0332] Physical properties of the fiber-reinforced resin molded article of Example 6B

[0333] The fiber-reinforced resin molded body of Example 6B was made by stacking four sheets of the prepreg of Example 6B. The prepreg of Example 6B was made by setting the thermosetting resin powder as resin D2 / resin E2 = 1 / 1 and the fiber substrate as one sheet. The molded body of Example 6B had a thickness of 0.8 mm, a VF value of 59%, a flexural strength of 910 MPa, a flexural modulus of elasticity of 61 GPa, and an appearance of "○". It had high strength and rigidity and a good appearance. In addition, Example 6B, which used a mixed resin of resin D2 / resin E2 = 1 / 1, had the same high strength and rigidity as Example 5B, which used a mixed resin of resin A2 / resin C2 = 1 / 1.

[0334] Properties of the fiber-reinforced resin molded article of Example 7B

[0335] The fiber-reinforced resin molded body of Example 7B was made by stacking four sheets of the prepreg of Example 7B. The prepreg of Example 7B was made by setting the thermosetting resin powder as resin D2 / resin E2 / resin C2 = 1 / 1 / 1 and the fiber substrate as one sheet. The molded body of Example 7B had a thickness of 0.8 mm, a VF value of 58%, a flexural strength of 930 MPa, a flexural modulus of elasticity of 59 GPa, and an appearance of "○". It had high strength and rigidity and a good appearance. In addition, Example 7B, which used a mixed resin of resin D2 / resin E2 / resin C2 = 1 / 1 / 1, had the same high strength and rigidity as Example 5B, which used a mixed resin of resin A2 / resin C2 = 1 / 1, and Example 6B, which used a mixed resin of resin D2 / resin E2 = 1 / 1.

[0336] The physical properties of the fiber-reinforced resin molded article of Comparative Example 1B

[0337] The fiber-reinforced resin molded body of Comparative Example 1B was made by stacking four sheets of the prepreg of Comparative Example 1. The prepreg of Comparative Example 1 was made by setting the thermosetting resin powder as resin F2 and the fiber substrate as one sheet. However, due to the poor impregnation of resin F2, it was impossible to obtain a molded body with uniform thermosetting resin impregnation. Therefore, it was impossible to measure the thickness, VF value, flexural strength, and flexural modulus.

[0338] The physical properties of the fiber-reinforced resin molded article of Comparative Example 2B

[0339] The fiber-reinforced resin molded body of Comparative Example 2B was made by stacking four sheets of the prepreg of Comparative Example 2B. The prepreg of Comparative Example 2B was made by setting the thermosetting resin powder as resin A2 / resin D2 = 1 / 2 and the fiber substrate as one sheet. However, due to the insufficient curing of the thermosetting resin, the molded body deformed during demolding, so the thickness, VF value, flexural strength and flexural modulus could not be measured.

[0340] <Evaluation of the storage stability of prepreg>

[0341] To evaluate the storage stability of prepregs caused by differences in thermosetting resins, after preparing the prepregs of Example 1B using resin A2, Example 4B using resin B2, Example 5B using a mixed resin of resin A2 / resin C2 = 1 / 1, Example 6B using a mixed resin of resin D2 / resin E2 = 1 / 1, and Example 7B using a mixed resin of resin D2 / resin E2 / resin C2 = 1 / 1 / 1, they were stored at 23°C and 50% humidity for 90 days, and then fiber-reinforced molded bodies were made in the same manner as the corresponding examples described above.

[0342] The appearance of the fabricated fiber-reinforced resin molded articles was judged, and the flexural strength and flexural modulus were measured. The results were compared with those obtained by fabricating fiber-reinforced resin molded articles using the prepreg immediately after its initial fabrication. Figure 12 The results shown are compared. The results of the storage stability of the prepreg are as follows: Figure 13 As shown. Figure 13 The flexural strength retention rate is a value relative to the flexural strength of a fiber-reinforced resin molded body made using freshly prepared prepreg. Figure 12 The percentage (%) of the bending strength value shown. Additionally, the flexural modulus retention rate is the value of the flexural modulus relative to the flexural modulus of the fiber-reinforced resin molded body made using the freshly prepared prepreg. Figure 12 The percentage (%) of the value of the flexural modulus shown.

[0343] For fiber-reinforced resin molded articles made from prepreg that has been prepared for 90 days, please explain Figure 13 The results are shown.

[0344] Example 1B (Resin A2)

[0345] For the fiber-reinforced resin molded article of Example 1B made from the prepreg of Resin A2 after 90 days, the appearance of the molded article is “○”, the flexural strength is 570 MPa, the flexural modulus is 48 GPa, the flexural strength retention rate is 93%, the flexural modulus retention rate is 92%, and the physical property reduction of the fiber-reinforced resin molded article caused by the storage of the prepreg is small.

[0346] Example 4B (Resin B2)

[0347] For the fiber-reinforced resin molded article of Example 4B made from the prepreg of Resin B2 after 90 days, the appearance of the molded article is “○”, the flexural strength is 420 MPa, the flexural modulus is 42 GPa, the flexural strength retention rate is 91%, the flexural modulus retention rate is 91%, and the physical property reduction of the fiber-reinforced resin molded article caused by the storage of the prepreg is small.

[0348] Example 5B (Resin A2 / Resin C2 = 1 / 1)

[0349] For the fiber-reinforced resin molded article of Example 5B made from the prepreg of the mixed resin of Resin A2 / Resin C2 = 1 / 1 after 90 days, the appearance of the molded article is “○”, the flexural strength is 910 MPa, the flexural modulus is 56 GPa, the flexural strength retention rate is 93%, the flexural modulus retention rate is 93%, and the decrease in physical properties of the fiber-reinforced resin molded article due to the storage of the prepreg is small.

[0350] Example 6B (Resin D2 / Resin E2 = 1 / 1)

[0351] For the fiber-reinforced resin molded article of Example 6B made from the prepreg of the mixed resin of resin D2 / resin E2 = 1 / 1 after 90 days, the appearance of the molded article is “○”, the flexural strength is 880 MPa, the flexural modulus is 60 GPa, the flexural strength retention rate is 97%, the flexural modulus retention rate is 98%, and the decrease in physical properties of the fiber-reinforced resin molded article due to the storage of the prepreg is small.

[0352] Example 7B (Resin D2 / Resin E2 / Resin C2 = 1 / 1 / 1)

[0353] For the fiber-reinforced resin molded article of Example 7B made from the prepreg of the mixed resin of resin D2 / resin E2 / resin C2 = 1 / 1 / 1 after 90 days, the appearance of the molded article is “○”, the flexural strength is 880 MPa, the flexural modulus is 56 GPa, the flexural strength retention rate is 95%, the flexural modulus retention rate is 95%, and the decrease in physical properties of the fiber-reinforced resin molded article due to the storage of the prepreg is small.

[0354] Thus, according to the present invention, the prepreg is simple and inexpensive to produce, and a prepreg with good storage stability can be obtained. Furthermore, fiber-reinforced resin molded articles with good quality can be obtained from this prepreg.

[0355] Furthermore, although only a flat shape is shown as the shape of the fiber-reinforced resin molded body in the embodiments, in the present invention, the shape (mold shape) of the fiber-reinforced resin molded body is not limited to a flat shape, and can be set to any shape such as a curved shape or a concave-convex shape.

[0356] Furthermore, this method is not limited to the above embodiments and can be modified within the scope of the main idea.

[0357] <Third Form>

[0358] The implementation method of the third form will be described.

[0359] 1. Fiber-reinforced molded body 210

[0360] In the fiber-reinforced molded body 210, the fiber substrate 211 is integrally formed with a thermosetting resin sheet 215 containing a thermosetting resin. The viscosity of the thermosetting resin at the curing reaction start temperature Tb℃ is less than 2000 Pa·s, and the maximum viscosity within the range of the curing reaction start temperature Tb℃ to 190℃ is more than 1000 Pa·s.

[0361] (1) Fiber substrate 211

[0362] The fiber substrate 211 can be a single layer or multiple layers, the number of layers being determined according to the application of the fiber-reinforced molded body 210. Figure 14 , 15 In the example shown, a four-layer fiber substrate 211 is illustrated. The fiber substrate 211 can be made of fabrics or nonwovens such as glass fiber, polyaramid fiber, basalt fiber, or carbon fiber, and is not particularly limited. However, carbon fiber fabrics are preferred due to their excellent lightweight and high rigidity. As for the carbon fiber fabric, fabrics woven in a way that involves weaving fibers in more than one direction are preferred. For example, plain weave, twill weave, satin weave, and triaxial weave fabrics composed of warp and weft yarns are preferred. Furthermore, from the viewpoint of the impregnation of the thermosetting resin contained in the resin sheet 215 and the rigidity of the fiber-reinforced molded body 210, a fiber weight of 50–600 g / m² is preferred for the aforementioned carbon fiber fabric. 2 .

[0363] (2) Resin sheets containing thermosetting resin 215

[0364] When manufacturing the fiber-reinforced molded body 210, a thermosetting resin that is solid at room temperature (5℃~35℃) is used. The solid shape is not particularly limited. Examples of solid shapes include spherical, needle-like, fragmented, and powdery forms.

[0365] Preferably, the resin sheet 215 has a sheet substrate. By having a sheet substrate, the strength of the resin sheet 215 is increased, thus improving its workability. Furthermore, even when the resin sheet 215 does not have a sheet substrate, its workability is still good compared to using powdered resin.

[0366] The structure of the sheet substrate is not particularly limited. Preferably, the sheet substrate has a structure in which molten resin can permeate. The structure in which molten resin can permeate is not particularly limited; examples include structures with interconnecting pores. Furthermore, it is preferable that the sheet substrate does not melt at the reaction initiation temperature (Tb) of the thermosetting resin.

[0367] The preferred sheet substrate is selected from one or more of the group consisting of foam, nonwoven fabric, and fiber sheet. If the sheet substrate has these structures, the thermosetting resin can be adequately retained within the space of the sheet substrate.

[0368] There are no particular limitations on the material of the sheet substrate. Preferably, the material of the sheet substrate is selected from one or more of the group consisting of urethane, rayon, polyester, and carbon.

[0369] Specifically, the preferred substrate is selected from one or more of the following groups: urethane foam, nonwoven fabric of rayon and polyester (PET), PET nonwoven fabric, and carbon fiber sheet.

[0370] There is no particular limitation on the thickness of the resin sheet substrate. From the viewpoint of fully maintaining the thermosetting resin required for adhesion, it is preferable that the thickness of the resin sheet substrate is 0.05 mm or more and 1.0 mm or less, and more preferably 0.08 mm or more and 0.7 mm or less.

[0371] There is no particular limitation on the unit weight of the resin sheet substrate. Preferably, the unit weight of the resin sheet substrate is 20 g / m³. 2 Above and 50g / m 2 The following is more preferably 30g / m 2 Above and 45g / m 2 the following.

[0372] The resin sheet 215 is configured to contact the fiber substrate 211. If the fiber substrate 211 and the resin sheet 215 are heated and compressed together, the thermosetting resin contained in the resin sheet 215 melts and impregnates the fiber substrate 211, then solidifies. As a configuration in which the resin sheet 215 is in contact with the fiber substrate 211, if the fiber substrate 211 is a single layer, the resin sheet 215 is disposed on at least one of the upper or lower surfaces of the single-layer fiber substrate 211. Alternatively, if the fiber substrate 211 is multilayered, a configuration in which the resin sheet 215 is disposed on at least one surface, i.e., the uppermost surface, the lowermost surface, or the lamination surface (between fiber substrates) of the multilayer.

[0373] If the melting start temperature of the thermosetting resin is set to Ta℃ and the curing reaction start temperature is set to Tb℃, then the thermosetting resin preferably satisfies 30≤(Tb-Ta)≤100. By setting (Tb-Ta) to this range, the molten thermosetting resin can be fully impregnated in the fiber substrate 211, and a fiber-reinforced molded body 210 with uniform physical properties can be obtained.

[0374] At temperatures above the melting start temperature Ta℃, the minimum viscosity of the thermosetting resin is 2000 Pa·s or less. Preferably, this minimum viscosity is 1500 Pa·s or less. By setting the minimum viscosity within this range, the molten thermosetting resin can be fully impregnated in the fiber substrate 211, resulting in a fiber-reinforced molded body 210 with uniform physical properties. There is no particular limitation on the lower limit of the minimum viscosity. Preferably, the lower limit of the minimum viscosity is 0.005 Pa·s.

[0375] In addition, the lowest viscosity at temperatures above the melting start temperature Ta℃ is the same as the viscosity at the curing reaction start temperature Tb℃.

[0376] Furthermore, the thermosetting resin preferably has a maximum viscosity of 1000 Pa·s or higher within a temperature range of Tb℃ to 190℃, which is the starting temperature of the curing reaction. By setting the maximum viscosity within this range, the molten thermosetting resin can be impregnated and retained within the fiber substrate 211, resulting in good shapeability of the fiber-reinforced molded body 210 and the attainment of sufficient strength in a short time. There is no particular limitation on the upper limit of the maximum viscosity, but a preferred upper limit is 300,000 Pa·s.

[0377] The preferred melting start temperature Ta of the thermosetting resin is 60 to 100°C. By setting the melting start temperature Ta of the thermosetting resin to this range, the temperature can be easily adjusted when the laminate in which the resin sheet 215 is disposed on at least one fiber substrate between the fiber substrates 211 is heated and compressed to melt and solidify the thermosetting resin.

[0378] The thermosetting resin that satisfies the above-mentioned melting start temperature Ta℃, curing reaction start temperature Tb℃, (Tb-Ta) range, minimum viscosity, and maximum viscosity is preferably selected from the group consisting of phenolic resin, mixed resins of phenolic resin and epoxy resin, mixed resins of phenolic resin and cyanate ester resin, mixed resins of epoxy resin and cyanate ester resin, and mixed resins of phenolic resin, cyanate ester resin, and epoxy resin. Phenolic resin, due to its excellent flame retardancy, can impart excellent strength and flame retardancy to the fiber-reinforced molded body 210.

[0379] As a phenolic resin, Novolac (phenolic varnish) type powdered phenolic resin is preferred, for example. There are no particular limitations on the physical properties of the phenolic resin. For example, phenolic resins with the following properties are suitable.

[0380] Melting point: Above 80℃ and below 100℃

[0381] As an epoxy resin, bisphenol A type solid resin is preferred, for example. There are no particular limitations on the physical properties of the epoxy resin. For example, epoxy resins with the following properties are suitable.

[0382] • Epoxy equivalent: 400g / eq or more and 1000g / eq or less

[0383] • Softening point: Above 60℃ and below 100℃

[0384] Viscosity: ≥0.10 Pa·s and ≤0.30 Pa·s (25℃)

[0385] Cyanate ester resins are thermosetting resins containing cyanate groups, also known as cyanate ester monomers. There are no particular limitations on the physical properties of cyanate ester resins before curing. For example, cyanate ester resins with the following properties are suitable.

[0386] Melting point: Above 75℃ and below 85℃

[0387] Viscosity: ≥0.010 Pa·s and ≤0.015 Pa·s (80℃)

[0388] In addition, various powder additives such as pigments, antibacterial agents, and ultraviolet absorbers can be added to thermosetting resins within a range that does not affect the viscosity or reactivity of the thermosetting resin.

[0389] The unit weight of the thermosetting resin in the resin sheet 215 is not particularly limited. However, from the viewpoint of ensuring the strength of the fiber-reinforced molded body 210 and not affecting its appearance, a unit weight of 200 g / m² for the thermosetting resin is preferred. 2 Above and 800g / m 2 The following is more preferably 400g / m 2 Above and 600g / m 2 the following.

[0390] (3) Physical properties of fiber-reinforced molded body 210

[0391] The flexural modulus of the fiber-reinforced molded body 210 (JIS K7074 A method) is not particularly limited. From the viewpoint of high rigidity, it is preferable that the flexural modulus of the fiber-reinforced molded body 210 is 40 GPa or more, and more preferably 50 GPa or more.

[0392] The flexural strength (JIS K7074 A method) of the fiber-reinforced molded body 210 is not particularly limited. From the viewpoint of high strength, it is preferable that the flexural strength of the fiber-reinforced molded body 210 is 400 MPa or more, and more preferably 800 MPa or more.

[0393] The specific gravity of the fiber-reinforced molded body 210 is not particularly limited. From the viewpoint of not affecting lightweight and appearance, it is preferable that the specific gravity of the fiber-reinforced molded body 210 is 1.10 or more and 1.80 or less, more preferably 1.30 or more and 1.69 or less.

[0394] 2. Manufacturing method of fiber-reinforced molded body 210

[0395] The method for manufacturing the fiber-reinforced molded body 210 of the present invention is carried out in the following manner: with the fiber substrate 211 and the resin sheet 215 overlapping, the material is heated and compressed through a mold to impregnate the fiber substrate 211 with a thermosetting resin and then cure it. The fiber substrate 211, the resin sheet 215, and the thermosetting resin are directly described in "1. Fiber-reinforced molded body 210".

[0396] The resin sheet 215 is configured as described above. In the case of a single layer, it is disposed on at least one of the upper or lower surfaces of the fiber substrate 211. In the case of a multilayer fiber substrate 211, it is disposed on at least one of the uppermost surface, the lowermost surface, and the laminated surfaces (between fiber substrates 211).

[0397] Furthermore, when the resin sheet 215 is disposed on the laminated surfaces (between fiber substrates 211) of the multilayer fiber substrate 211, it is not limited to being disposed on one laminated surface (between one fiber substrate 211), but may be disposed on all laminated surfaces (between all fiber substrates) or laminated surfaces separated by a specified number of layers (between fiber substrates 211 separated by a specified number of layers). The position of the disposed surface and the number of disposed surfaces are appropriately determined according to the number of layers of the fiber substrate 211.

[0398] In addition, when the resin sheet 215 is disposed in contact with the upper or lower surface of a single-layer fiber substrate 211, or the uppermost or lowermost surface of a multi-layer fiber substrate 211, release paper may be disposed between the resin sheet 215 and the mold surface of the mold for ease of operation.

[0399] use Figure 15 right Figure 14An embodiment of the manufacturing method of the fiber-reinforced molded body 210, which is composed of four layers of fiber substrates 211, will be described. Furthermore, in the following description of the manufacturing method, for the plurality of fiber substrates 211, in order to easily grasp their vertical positional relationship, multiple fiber substrates 211 are represented by reference numerals combining "211" and "letter" such as "211A". Similarly, for the plurality of resin sheets 215, in order to easily grasp their vertical positional relationship, multiple resin sheets 215 are represented by reference numerals combining "215" and "letter" such as "215A".

[0400] exist Figure 15 In the embodiment shown, when four fiber substrates 211A to 211D are stacked, resin sheets 215A and 215B are disposed between the fiber substrates 211 (between fiber substrates 211B and fiber substrates 211C and 211D) between the two lower fiber substrates 211A and 211B and the two upper fiber substrates 211C and 211D.

[0401] Preferably, the amount of thermosetting resin contained in resin sheets 215A and 215B is adjusted so that the VF value (%) of the fiber-reinforced molded body 210 reaches 40-70%. The VF value (%) is calculated by (total weight of fiber substrate / fiber density) / (volume of fiber-reinforced molded body) × 100.

[0402] Resin sheets 215A and 215B are disposed between fiber substrates 211B and 211C and stacked to form a laminate of fiber substrates 211A to 211D. The laminate is then clamped between the lower mold 231 and the upper mold 232 of a heated mold 230 and subjected to heating and compression. The mold 230 is heated to the temperature Tc℃ at which the thermosetting resin can melt and solidify by a heating unit such as an electric heater.

[0403] The relationship between the temperature Tc℃ during heat compression (temperature Tc℃ of the mold 30) and the melting start temperature Ta℃ and curing reaction start temperature Tb℃ of the thermosetting resin is as follows:

[0404] The preferred setting is [Tb+(Tb-Ta) / 3]-15≤Tc≤[Tb+(Tb-Ta) / 3]+20. For example, when Ta℃=70℃ and Tb℃=130℃, Tc℃ reaches 135℃~170℃.

[0405] In order for the thermosetting resin contained in the resin sheets 215A and 215B between the fiber substrates 211 to be well impregnated in the fiber substrates 211A to 211D after melting, it is preferable that the pressure (compression) of the fiber substrates 211A to 211D during the heating and compression by the mold 230 is 2MPa to 20MPa.

[0406] In addition, the compression ratio (%) of the fiber substrates 211A to 211D is a value calculated by (the gap between the die surface of the lower die 231 and the die surface of the upper die 232) / (the total thickness of all layers of the fiber substrate) × 100, preferably 60 to 100%.

[0407] By heating the laminated body using mold 230, the thermosetting resin contained in the resin sheets 215A and 215B between the fiber substrates 211 (between fiber substrates 211B and 211C) melts. Furthermore, the molten thermosetting resin is impregnated into the lower fiber substrates 211B and 211A and the upper fiber substrates 211C and 211D by compression of the laminated body. Then, by curing the thermosetting resin impregnated in the fiber substrates 211A to 211D, the fiber substrates 211A to 211D are integrated under compression, resulting in a mold surface shape shaped like the lower mold 231 and the upper mold 232. Figure 14 Fiber-reinforced molded body 210.

[0408] Figure 16 An embodiment is shown in which four fiber substrates 211A to 211D are stacked, resin sheets 215A to 215C are placed between the fiber substrates, and the mixture is heated and compressed using a mold 230.

[0409] The amount (total) of thermosetting resin, the heating temperature of mold 230, the pressure of the laminate, etc. Figure 15 As described in the implementation method.

[0410] exist Figure 17 In the embodiment shown, when 10 fiber substrates 211A to 211J are stacked, 5 resin sheets 215A to 215E are disposed between the fiber substrates 211 (between fiber substrates 211E and fiber substrates 211F to 211J) between the lower 5 fiber substrates 211A to 211E and the upper 5 fiber substrates 211F to 211J.

[0411] 3. Resin sheet 215

[0412] The resin sheet 215 used in manufacturing the fiber-reinforced molded body 210 contains a thermosetting resin. That is, the resin sheet 215 carries the thermosetting resin in an uncured state. The resin sheet 215 and the thermosetting resin are directly described in "1. Fiber-reinforced molded body 210".

[0413] <Example>

[0414] Using the thermosetting resins shown in Tables 1 and 2, fiber-reinforced molded articles of Examples 1C to 10C and Comparative Examples 1C and 2C were prepared in the following manner. Table 4 summarizes the characteristics of various sheet substrates used to make the fiber-reinforced molded articles. In addition, the viscosity of the thermosetting resins was measured under the following conditions using a Rheosol-G3000 rheometer manufactured by UBM Corporation.

[0415] 1) Take 0.4g of the sample and form it into granules (approximately φ18mm in diameter and 0.4mm in thickness). Clamp the formed granules onto a parallel plate with a diameter of φ18mm.

[0416] 2) Under the conditions of heating rate of 5℃ / min, frequency of 1Hz, rotation angle (strain) of 0.1deg and constant heating rate, the dynamic viscosity was measured at 2℃ intervals between 40℃ and 200℃.

[0417]

[0418]

[0419]

[0420] [Table 4]

[0421] PET nonwoven fabric 0.08 45 urethane resin foam 0.70 35 Rayon / Polyester Nonwoven Fabric 0.22 31 carbon fiber sheet 0.34 31

[0422] 1. Fabrication of fiber-reinforced molded articles

[0423] (1) Example 1C

[0424] As a solid thermosetting resin, a mixed resin is used, which is prepared by uniformly mixing cyanate ester resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name: CYTESTER TA, average particle size: 100 μm), epoxy resin (manufactured by DIC Co., Ltd., product name: AM-020-P, average particle size: 100 μm) and phenolic resin (manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50235D, average particle size: 90 μm) in a weight ratio of 3:1:1.

[0425] The characteristics of the mixed resin of Example 1C are as follows and are recorded in Tables 1 and 2. Figure 18 The graph shows the viscosity measurement results of the mixed resin of Example 1C.

[0426] • Melting start temperature Ta℃: 69℃

[0427] • Curing reaction start temperature Tb℃: 135℃

[0428] (Tb-Ta): 66℃

[0429] • Lowest viscosity (lowest viscosity at temperatures above the melting point Ta℃): 59 Pa·s

[0430] • Highest viscosity (the highest viscosity within the temperature range of the curing reaction start temperature Tb℃~190℃): 8768 Pa·s

[0431] The value of (Tb-Ta) / 3: 22℃

[0432] The value of Tb + (Tb - Ta) / 3 is 157℃.

[0433] As the substrate for the resin sheet, the PET nonwoven fabric shown in Table 4 (manufactured by VILENE Co., Ltd., Japan, product name: JH-1004N1, unit weight: 45g / m²) was used. 2 The substrate (0.08mm thick) is cut into 200mm×250mm pieces.

[0434] 20g of the above-mentioned solid thermosetting resin is applied to a single substrate sheet to form a pre-molded substrate sheet.

[0435] Next, a pre-forming sheet substrate is placed on the forming surface of the lower mold of a mold heated to 100°C. The mold is then closed, and the substrate is heated and compressed at a pressure of 1 MPa for 1 minute to melt the solid thermosetting resin and hold it on the sheet substrate. After cooling, a resin sheet is produced.

[0436] Two resin sheets made in this manner were prepared. In addition, a 1mm thick SUS spacer was placed between the lower and upper molds, and a 0.05mm thick PET film was placed between the upper and lower parts of the pre-molded substrate to adjust the thickness of the resin sheets.

[0437] As the reinforcing fiber substrate, prepare 4 pieces of carbon fiber fabric (manufactured by Teijin Corporation, product name: W-3101, unit weight: 200g / m²). 2 The substrate, with a thickness of 0.22mm, is cut into 200mm × 250mm pieces. Each cut carbon fiber piece weighs 12g. First, two pieces of carbon fiber fabric are prepared, followed by two resin sheets, and then two more pieces of carbon fiber fabric, to create the pre-formed laminate. Figure 15 The image schematically illustrates the stacked state. Example 1C is shown below. Figure 15 As shown, two resin sheets are arranged between the central fiber substrate (carbon fiber fabric) as pre-molding laminates.

[0438] Next, the pre-molding laminate is placed on the molding surface of the lower die of a mold heated to 160°C. The mold is then closed, and the solid thermosetting resin is heated and compressed at a pressure of 10 MPa for 10 minutes to melt and solidify. By melting the solid thermosetting resin and applying pressure, the resin impregnates each layer of the fiber substrate. After the solid thermosetting resin has cured, a fiber-reinforced molded body is produced, where the fiber substrate is integrated with the resin sheet through the thermosetting resin. Furthermore, a 1 mm thick SUS spacer is placed between the lower and upper dies used for stamping, and the spacing between the lower and upper dies is adjusted to adjust the thickness of the fiber-reinforced molded body.

[0439] (2) Example 2C

[0440] As a solid thermosetting resin, a mixed resin was used, which was prepared by uniformly mixing cyanate ester resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name: CYTESTER TA, average particle size: 100 μm), epoxy resin (manufactured by DIC Co., Ltd., product name: AM-030-P, average particle size: 100 μm) and phenolic resin (manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50235D, average particle size: 90 μm) in a weight ratio of 1:1:1. The mold temperature for molding the fiber-reinforced molded body was set to 150°C. Otherwise, the fiber-reinforced molded body was made in the same manner as in Example 1C.

[0441] The characteristics of the mixed resin of Example 2C are as follows, and are described in Tables 1 and 2.

[0442] • Melting start temperature Ta℃: 95℃

[0443] • Curing reaction start temperature Tb℃: 135℃

[0444] (Tb-Ta): 40℃

[0445] • Lowest viscosity (lowest viscosity at temperatures above the melting point Ta℃): 1500 Pa·s

[0446] • Highest viscosity (the highest viscosity within the temperature range of curing reaction start temperature Tb℃~190℃): 209004 Pa·s

[0447] The value of (Tb-Ta) / 3: 13℃

[0448] The value of Tb + (Tb - Ta) / 3: 148℃

[0449] (3) Example 3C

[0450] As a solid thermosetting resin, a mixed resin was used, which was uniformly mixed with phenolic resin (manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50252, average particle size: 30 μm) and epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd., product name: jER-1001, average particle size: 100 μm) in a weight ratio of 1:1. The mold temperature for molding the fiber-reinforced molded body was set to 150°C. Otherwise, the fiber-reinforced molded body was made in the same manner as in Example 1C.

[0451] The characteristics of the mixed resin of Example 3C are as follows, and are described in Tables 1 and 2.

[0452] • Melting start temperature Ta℃: 73℃

[0453] • Curing reaction start temperature Tb℃: 140℃

[0454] (Tb-Ta): 67℃

[0455] • Lowest viscosity (lowest viscosity at temperatures above the melting point Ta℃): 22 Pa·s

[0456] • Highest viscosity (the highest viscosity within the temperature range of curing reaction start temperature Tb℃~190℃): 5180 Pa·s

[0457] The value of (Tb-Ta) / 3: 22℃

[0458] The value of Tb + (Tb - Ta) / 3 is 163℃.

[0459] (4) Example 4C

[0460] As a solid thermosetting resin, a mixed resin was used, which was uniformly mixed with phenolic resin (manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50235D, average particle size: 90 μm) and cyanate ester resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name: CYTESTERTA, average particle size: 100 μm) in a 1:1 weight ratio. The mold temperature for molding the fiber-reinforced molded body was set to 170°C. Otherwise, the fiber-reinforced molded body was made in the same manner as in Example 1C.

[0461] The characteristics of the mixed resin of Example 4C are as follows, and are described in Tables 1 and 2.

[0462] • Melting start temperature Ta℃: 76℃

[0463] • Curing reaction start temperature Tb℃: 138℃

[0464] (Tb-Ta): 62℃

[0465] • Lowest viscosity (lowest viscosity at temperatures above the melting point Ta℃): 475 Pa·s

[0466] • Highest viscosity (the highest viscosity within the temperature range of curing reaction start temperature Tb℃~190℃): 51895 Pa·s

[0467] The value of (Tb-Ta) / 3: 21℃

[0468] The value of Tb + (Tb - Ta) / 3 is 159℃.

[0469] (5) Example 5C

[0470] As a solid thermosetting resin, a mixed resin was used, which was prepared by uniformly mixing epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name: jER-1001, average particle size: 100 μm) and cyanate ester resin (manufactured by Mitsubishi Gas Chemical Corporation, product name: CYTESTERTA, average particle size: 100 μm) in a weight ratio of 1:1. The mold temperature for molding the fiber-reinforced molded body was set to 170°C. Otherwise, the fiber-reinforced molded body was made in the same manner as in Example 1C.

[0471] The characteristics of the mixed resin of Example 5C are as follows, and are described in Tables 1 and 2.

[0472] • Melting start temperature Ta℃: 75℃

[0473] • Curing reaction start temperature Tb℃: 139℃

[0474] (Tb-Ta): 64℃

[0475] • Lowest viscosity (lowest viscosity at temperatures above the melting point Ta℃): 575 Pa·s

[0476] • Highest viscosity (the highest viscosity within the temperature range of curing reaction start temperature Tb℃~190℃): 19025 Pa·s

[0477] The value of (Tb-Ta) / 3: 21℃

[0478] The value of Tb+(Tb-Ta) / 3: 160℃

[0479] (6) Example 6C

[0480] In addition to preparing 4 reinforcing fiber substrates identical to those in Example 1C and 3 resin sheets identical to those in Example 1C, such as Figure 16 As shown, except for the placement of a resin sheet between each fiber substrate layer, the fiber-reinforced molded body is manufactured in the same manner as in Example 1C.

[0481] (7) Example 7C

[0482] Prepare 10 reinforcing fiber substrates identical to those in Example 1C. Stack 5 of these fiber substrates, then place 5 resin sheets on top, and finally stack the remaining 5 fiber substrates on top, thereby creating the pre-molding substrate. Otherwise, fabricate the fiber-reinforced molded body in the same manner as in Example 1C. Figure 17 The image shows a schematic representation of the stacked state.

[0483] (8) Example 8C

[0484] In addition to using urethane resin foam cut to a thickness of 0.7mm and a planar size of 200mm × 300mm (manufactured by INOAC CORPORATION, product name: MF-50, unit weight 35g / m³), 2 In addition to serving as a sheet substrate, a fiber-reinforced molded body is produced in the same manner as in Example 1C.

[0485] (9) Example 9C

[0486] In addition to using rayon / polyester nonwoven fabric cut to a thickness of 0.22mm and a flat size of 200mm×300mm (manufactured by Kuraray Trading Co., Ltd., product name: SF-30C, unit weight 31g / m²), 2 In addition to serving as a sheet substrate, a fiber-reinforced molded body is produced in the same manner as in Example 1C.

[0487] (10) Example 10C

[0488] In addition to using carbon fiber sheets cut to a thickness of 0.34mm and a planar size of 200mm × 300mm (manufactured by Awa Paper Co., Ltd., product name: CARMIX C-2, unit weight 31g / m³), 2 In addition to serving as a sheet substrate, a fiber-reinforced molded body is produced in the same manner as in Example 1C.

[0489] (11) Comparative Example 1C

[0490] As a solid thermosetting resin, phenolic resin (manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50699, average particle size: 30 μm) was used. The mold temperature for manufacturing the resin sheet was set to 80°C, and the mold temperature for molding the fiber-reinforced molded body was set to 100°C. Otherwise, the fiber-reinforced molded body was manufactured in the same manner as in Example 1C. The resin had high viscosity (fast reaction) and poor impregnation properties, making it impossible to obtain a uniform fiber-reinforced molded body.

[0491] The properties of the resin of Comparative Example 1C are as follows, and are described in Tables 1 and 2.

[0492] Figure 18 The graph shows the viscosity test results of the resin of Comparative Example 1C.

[0493] • Melting start temperature Ta℃: 72℃

[0494] • Curing reaction start temperature Tb℃: 91℃

[0495] (Tb-Ta): 19℃

[0496] • Lowest viscosity (lowest viscosity at temperatures above the melting point Ta °C): 118908 Pa·s

[0497] • Highest viscosity (the highest viscosity within the temperature range of curing reaction start temperature Tb℃~190℃): 164468 Pa·s

[0498] The value of (Tb-Ta) / 3: 6℃

[0499] The value of Tb+(Tb-Ta) / 3 at 100℃

[0500] (12) Comparative Example 2C

[0501] As a solid thermosetting resin, a 1:2 mixture (by weight) of two phenolic resins (Sumitomo Bakelite Co., Ltd., product name: PR-50252, average particle size: 30 μm and Sumitomo Bakelite Co., Ltd., product name: PR-50235D, average particle size: 90 μm) was used. The mold temperature for molding the fiber-reinforced molded body was set to 160°C. Otherwise, the fiber-reinforced molded body was produced in the same manner as in Example 1C. The resin was not fully cured, and deformation occurred during demolding.

[0502] The properties of the resin of Comparative Example 2C are as follows, and are described in Tables 1 and 2.

[0503] Figure 18 The graph shows the viscosity test results of the resin of Comparative Example 2C.

[0504] • Melting start temperature Ta℃: 80℃

[0505] • Curing reaction start temperature Tb℃: 140℃

[0506] (Tb-Ta): 60℃

[0507] • Lowest viscosity (lowest viscosity at temperatures above the melting point Ta℃): 21 Pa·s

[0508] • Maximum viscosity (highest viscosity within the temperature range of curing reaction start temperature Tb℃~190℃): 260 Pa·s

[0509] The value of (Tb-Ta) / 3: at 20℃

[0510] The value of Tb+(Tb-Ta) / 3: 160℃

[0511] 2. Physical properties of fiber-reinforced molded bodies, etc.

[0512] (1) Measurement method

[0513] The thickness (mm), flexural strength (MPa), flexural modulus (GPa), and appearance of the fiber-reinforced molded articles of Examples 1C to 10C and Comparative Examples 1C and 2C were measured. Table 3 shows the results.

[0514] Test pieces were cut from the fiber-reinforced molded body, and the flexural strength and flexural modulus were determined according to JIS K7074 A method.

[0515] Visual inspection is used to confirm the appearance. The appearance is judged by visually confirming whether there are any defects on the surface of the fiber-reinforced molded body caused by deformation or uneven resin impregnation. The condition without defects is rated as "○" and the condition with defects is rated as "×".

[0516] The thickness of each part of the fiber-reinforced molded body was measured by observing its cross-section using a digital microscope VHX-5000 (manufactured by KEYENCE Co., Ltd.). The thicknesses in Table 3 are the thicknesses near the central part of the fiber-reinforced molded body.

[0517] Specific gravity is calculated based on the weight and volume of the fiber-reinforced molded body. The volume of the fiber-reinforced molded body is calculated based on its thickness and area.

[0518] (2) Measurement results

[0519] Table 3 shows the measurement results.

[0520] The fiber-reinforced molded articles of Examples 1C-10C satisfy the following requirements (a) and (b). In contrast, the fiber-reinforced molded article of Comparative Example 1C does not satisfy requirement (a). Because Comparative Example 1C does not satisfy requirement (a), its resin viscosity is high, resulting in poor resin impregnation and an inability to obtain a uniform fiber-reinforced molded article. Furthermore, the fiber-reinforced molded article of Comparative Example 2C does not satisfy requirement (b). The resin in the fiber-reinforced molded article of Comparative Example 2C, which does not satisfy requirement (b), is not sufficiently cured, leading to deformation during demolding.

[0521] In the fiber-reinforced molded articles of Examples 1C-10C that satisfy requirements (a) and (b), by controlling the melting and curing characteristics of the solid thermosetting resin, fiber-reinforced resin composites with excellent appearance, strength, and lightweight can be obtained easily without the use of prepreg. Furthermore, it is known that in the fiber-reinforced molded articles of Examples 1C-10C, resin sheets (resin carrier sheets) can be easily manufactured, preventing powder scattering. Also, since no organic solvents are used in the manufacturing process, the working environment is excellent, and there are no air pollution problems.

[0522] • Requirement (a): The viscosity (minimum viscosity) at the curing reaction start temperature Tb℃ is below 2000 Pa·s.

[0523] • Requirement (b): The highest viscosity within the range of curing reaction start temperature Tb℃~190℃ is above 1000Pa·s.

[0524] In addition, by further satisfying the following requirement (c), the fiber-reinforced molded articles of Examples 1C-10C can be made to fully impregnate the fiber substrate with molten thermosetting resin, thereby obtaining a fiber-reinforced molded article with uniform physical properties.

[0525] • Requirement (c): 30 ≤ (Tb - Ta) ≤ 100.

[0526] Based on the above embodiments and comparative examples, the following invention can also be understood. The foregoing descriptions are appropriately referenced in the following explanations of specific matters disclosed.

[0527] A fiber-reinforced molded body is formed by impregnating a thermosetting resin in a laminate consisting of a fiber substrate and a sheet substrate different from the aforementioned fiber substrate.

[0528] 3. Effects of the Implementation Example

[0529] Based on the above embodiments, fiber-reinforced resin composites with excellent appearance, strength, and lightweight can be obtained. Furthermore, it has been confirmed that resin sheets can be manufactured using a simple method, preventing powder scattering. Since no organic solvents are used in the manufacturing process, the working environment is excellent, and there are no air pollution problems.

[0530] This method is not limited to the embodiments described in detail above, and various modifications or alterations are possible.

[0531] <Fourth Form>

[0532] The implementation method of the fourth form will be described. Figure 19The fiber-reinforced sandwich composite 310 shown in one embodiment is a structure in which the fiber substrate 311, the core material 315, and the thermosetting resin 321 are heated and compressed together, and bonded together by the curing of the thermosetting resin 321.

[0533] The fiber substrate 311 can be a single layer or multiple layers, and the number of layers can be determined according to the application of the fiber-reinforced sandwich composite 310. In the embodiments shown in the drawings, the fiber substrate 311 consists of four layers. The fiber substrate 311 can be a fabric or nonwoven fabric made of glass fiber, polyaramid fiber, basalt fiber, carbon fiber, etc., and there is no particular limitation. Carbon fiber fabric is preferred due to its excellent lightweight and high rigidity. As for the carbon fiber fabric, fabrics made with a weave where the fibers are not unidirectional are preferred; for example, plain weave fabrics, twill weave fabrics, satin weave fabrics composed of warp and weft yarns, and triaxial fabrics composed of yarns in three directions are preferred. Furthermore, from the viewpoint of the impregnation of the thermosetting resin 321 and the rigidity of the fiber-reinforced sandwich composite 310, a fiber weight of 50 to 600 g / m² is preferred for the aforementioned carbon fiber fabric. 2 .

[0534] The core material 315 has the effect of improving the strength of the fiber-reinforced sandwich composite 310, and preferably has a 5% compressive stress value of 0.15 MPa or more. More preferably, the 5% compressive stress ranges from 0.15 to 1 MPa. Furthermore, the 5% compressive stress is the stress when a core material cut to 50×50 mm dimensions is compressed by 5% of its thickness using a φ80 mm disc-shaped compressor at a speed of 5 mm / min. An example of a stress measuring device is the Shimadzu Autograph AG-X.

[0535] The preferred core material 315 has a density (JIS Z8807) of 20–120 kg / m³. 3 .

[0536] As the core material 315, a foam with an independent bubble structure is preferred. The independent bubble structure of the foam is such that the units (bubbles) are not interconnected and are mutually closed and independent. By making the core material 315 an independent bubble structure foam, molten thermosetting resin is less likely to penetrate into the independent bubble structure core material 315 during the manufacture of the fiber-reinforced sandwich composite 310, resulting in an excellent surface appearance of the fiber-reinforced sandwich composite 310. Furthermore, if the core material 315 is a foam with a continuous bubble structure where the units are open and interconnected, molten thermosetting resin easily penetrates into the continuous bubble structure core material 315 during the manufacture of the fiber-reinforced sandwich composite 310. Therefore, less thermosetting resin remains on the surface of the fiber-reinforced sandwich composite 310, potentially impairing its appearance.

[0537] Examples of foams that form the independent bubble structure of the core material 315 include polyethylene terephthalate foam (PET foam), polymethacrylimide foam (PMI foam), polyvinyl chloride foam (PVC foam), and rigid polyurethane foam (rigid PU foam).

[0538] The thickness of the core material 315 is determined according to the application of the fiber-reinforced sandwich composite 310, for example, about 3 to 20 mm.

[0539] Furthermore, the core material 315 is not limited to a single layer, but can also be multiple layers. When the core material 315 is a single layer and the fiber substrate 311 is multiple layers, it is preferable that the core material 315 is located between the fiber substrates 311.

[0540] There are no particular limitations on the manufacturing method of core material 315. For example, the following manufacturing methods can be cited.

[0541] • A method of filling resin foam particles into a mold, heating the resin foam particles with a heat medium such as hot water or steam to make them foam, and using the foaming pressure of the resin foam particles to fuse the foam particles together to create a foam body with the desired shape (in-mold foaming molding method).

[0542] • A method of producing foamed materials by feeding resin and bubble modifiers together to an extruder, melt-blending in the presence of foaming agents such as chemical foaming agents and physical foaming agents, and extruding the melt-blended material from the extruder to create foam (extrusion foaming method).

[0543] A method for manufacturing a foamed body by foaming a block-shaped foamed resin molded body containing a chemical foaming agent within a mold.

[0544] When manufacturing the fiber-reinforced sandwich composite 310, a solid, powdered thermosetting resin 321 is used. The shape of the powder is not particularly limited; it can be spherical, needle-like, or fragmented. Preferably, the thermosetting resin 321 powder is configured to be in contact with at least the fiber substrate 311 and the core material 315. For example, if the core material 315 is a single layer, the thermosetting resin 321 powder is disposed at least between the fiber substrate 311 and the core material 315; if the fiber substrate 311 is multilayered, the thermosetting resin 321 powder is disposed not only between the fiber substrate 311 and the core material 315, but also between the fiber substrates 311. Furthermore, when multiple core materials 315 are laminated in contact, it is preferable to dispose of the thermosetting resin 321 powder between the fiber substrate 311 and the core material 315, and between the core materials 315 themselves.

[0545] The powder of thermosetting resin 321 melts and is impregnated in fiber substrate 311 when heated and compressed together with fiber substrate 311 and core material 315, and is cured in contact with core material 315.

[0546] The viscosity of the thermosetting resin 321 at the curing reaction start temperature Tb℃ is 2000 Pa·s or less, preferably 1500 Pa·s or less. By setting the viscosity at the curing reaction start temperature Tb℃ within this range, the molten thermosetting resin 321 can be uniformly impregnated in the fiber substrate 311, and a fiber-reinforced sandwich composite 310 with uniform physical properties can be obtained.

[0547] Preferably, the thermosetting resin 321 has a maximum viscosity of 1000 Pa·s or higher within the temperature range of the curing reaction start temperature Tb℃ to 190℃. By setting the maximum viscosity within this range, the molten thermosetting resin 321 can be impregnated into the fiber substrate 311 and fully cured, resulting in good shapeability of the fiber-reinforced sandwich composite 310 and the attainment of sufficient strength in a short time.

[0548] In the relationship between the melting start temperature Ta℃, the curing reaction start temperature Tb℃, and the temperature Tc℃ during heating and compression of thermosetting resin 321...

[0549] The preferred setting is [Tb+(Tb-Ta) / 3]-15≤Tc≤[Tb+(Tb-Ta) / 3]+20.

[0550] More preferably, [Tb+(Tb-Ta) / 3]-10≤Tc≤[Tb+(Tb-Ta) / 3]+20. By setting the melting start temperature Ta℃, curing reaction start temperature Tb℃, and heating compression temperature Tc℃ of the thermosetting resin 321 to this relationship, the melting of the thermosetting resin 321 powder becomes good during heating compression, and the thermosetting resin 321 is easily impregnated into the fiber substrate 311, thus obtaining a fiber-reinforced sandwich composite 310 with uniform physical properties.

[0551] Preferably, the curing reaction start temperature Tb℃ - melting start temperature Ta℃ of the thermosetting resin 321 has a value of 30≤(Tb-Ta)≤100, more preferably 40≤(Tb-Ta)≤70. By setting (Tb-Ta) within this range, the molten thermosetting resin 321 can be fully impregnated in the fiber substrate 311, and a fiber-reinforced sandwich composite 310 with uniform physical properties can be obtained.

[0552] The preferred melting point Ta of thermosetting resin 321 is 60–100 °C. By setting the melting point Ta of thermosetting resin 321 within this range, the temperature adjustment for heating and compression can be easily achieved.

[0553] For thermosetting resins that satisfy the above-mentioned melting start temperature Ta℃, curing reaction start temperature Tb℃, (Tb-Ta) range, minimum viscosity, and maximum viscosity, resins selected from the group consisting of phenolic resins, mixed resins of phenolic resins and epoxy resins, mixed resins of phenolic resins and cyanate ester resins, and mixed resins of phenolic resins, cyanate ester resins, and epoxy resins are preferred. Phenolic resins, due to their excellent flame retardancy, can impart excellent strength and flame retardancy to the fiber-reinforced sandwich composite 310.

[0554] In addition, various powder additives such as pigments, antibacterial agents, and ultraviolet absorbers can be added to thermosetting resin 321 within a range that does not affect the viscosity or reactivity of the thermosetting resin.

[0555] The fiber-reinforced sandwich composite disclosed herein can be manufactured by: configuring the powder of thermosetting resin 321 to contact the fiber substrate 311 and the core material 315; heating and compressing the fiber substrate 311 and the core material 315 together with the powder of thermosetting resin 321 using a mold; thereby, the powder of thermosetting resin 321 can be melted and impregnated in the fiber substrate 311, and cured while in contact with the core material 315.

[0556] use Figure 20 right Figure 19 An embodiment of the manufacturing method of the fiber-reinforced sandwich composite 310 shown will be described. Furthermore, in the following description, for the fiber substrates 311 at multiple locations, in order to easily grasp their vertical positional relationship, they are sometimes indicated by a combination of numbers and letters, such as "311A".

[0557] exist Figure 20 In the embodiment shown, among the four fiber substrates 311A ​​to 311D, two fiber substrates 311A ​​and 311B are stacked, thermosetting resin powder 321A is disposed on them, core material 315 is disposed on them, thermosetting resin powder 321B is disposed on them, and then the remaining two fiber substrates 311C and 311D are stacked on them to form a pre-molding laminate.

[0558] From the viewpoint of easy melting, it is preferable that the particle size of the thermosetting resin powders 321A and 321B is 10 to 500 μm. Furthermore, it is preferable that the amount of thermosetting resin powders 321A and 321B is adjusted such that the VF value (%) of the molded body excluding the core foam portion is 40 to 70%. The VF value (%) is calculated by (total weight of fiber substrate / fiber density) / (volume of the molded body excluding the core foam portion) × 100.

[0559] The pre-molded laminate, formed by clamping the lower mold 331 and upper mold 332 of the heated mold 330, is then heated and compressed. A demolding plastic film or similar material may also be placed on the mold surface. The mold 330 is heated to the aforementioned temperature Tc℃ during heating and compression by a heating unit such as an electric heater.

[0560] In order for the thermosetting resin powders 321A and 321B to be well impregnated into the fiber substrates 311A ​​to 311D after melting, the pressure (compression) of the pre-molded laminate during heating and compression by the mold 330 is preferably 2 to 20 MPa.

[0561] By heating the laminated body using mold 330, the thermosetting resin powders 321A and 321B located on both sides (top and bottom) of the core material 315 melt. Furthermore, the molten thermosetting resin is impregnated into the lower fiber substrates 311B and 311A ​​and the upper fiber substrates 311C and 311D by compression of the laminated body before molding. Then, the thermosetting resin impregnated in the fiber substrates 311A ​​to 311D and in contact with the core material 315 is cured, thereby bonding the core material 315 between the fiber substrates 311A ​​to 311D and the fiber substrates 311B and 311C under compressed conditions, resulting in a mold surface shape shaped like the lower mold 331 and the upper mold 332. Figure 19 Fiber-reinforced sandwich composite 310.

[0562] <Example>

[0563] use Figure 21 Core materials shown and Figure 22 The powder of the thermosetting resin shown is used to make... Figure 23 The fiber-reinforced sandwich composites of Examples 1D to 7D and Comparative Examples 1D to 3D are shown.

[0564] Regarding the 5% compressive stress of the core material, the stress was measured when a core material cut to a size of 50×50mm was compressed by 5% relative to its thickness using a φ80mm disc compressor at a speed of 5mm / min. The stress measuring equipment was Shimadzu's Autograph AG-X.

[0565] The viscosity of thermosetting resins was determined using a Rheosol-G3000 rheometer manufactured by UBM Corporation under the following conditions.

[0566] 1) Take 0.4g of the sample and form it into granules (approximately φ18mm in diameter and 0.4mm in thickness). Clamp the formed granules onto a parallel plate with a diameter of φ18mm.

[0567] 2) Under the conditions of heating rate of 5℃ / min, frequency of 1Hz, rotation angle (strain) of 0.1deg and constant heating rate, the dynamic viscosity was measured at 2℃ intervals between 40℃ and 200℃.

[0568] The appearance of the fiber-reinforced sandwich composites of Examples 1D to 7D and Comparative Examples 1D to 3D was judged, and the density, thickness, flexural strength and flexural modulus were measured.

[0569] The appearance of the product is determined by visually inspecting the surface of the fiber-reinforced sandwich composite to check for defects caused by deformation or uneven resin impregnation. Products without defects are rated as "○", and products with defects are rated as "×".

[0570] Density was determined according to JIS Z8807.

[0571] The flexural strength and flexural modulus were determined according to JIS K7074 A method.

[0572] Example 1D

[0573] As the fiber substrate, prepare 4 sheets of carbon fiber fabric (manufactured by Teijin Corporation, product name: W-3101, unit weight: 200g / m²). 2 The substrate is cut into 210mm × 297mm pieces (0.22mm thick). Each piece of fiber substrate weighs 12.5g after cutting. Two pieces of the cut fiber substrate are stacked, and 25g of the following resin A3 is evenly distributed on it as a thermosetting resin powder. A sheet of polyethylene terephthalate foam (manufactured by 3A Composites Airex, AIREX(T10)) with an independent bubble structure is cut into 210 × 297mm pieces and 25g of resin A3 is evenly distributed on it. The remaining two pieces of fiber substrate are then stacked on top to form the pre-molding laminate.

[0574] Resin A3 is a phenolic resin manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50252, with an average particle size of 30μm.

[0575] Figure 24 The charts show the viscosity measurement results of resin A3 (Examples 1D, 6D, 7D).

[0576] The pre-molding laminate is placed on the molding surface (mold surface) of the lower mold of a mold heated to 150°C. The upper mold is then placed over the pre-molding laminate, and the mold is closed. The laminate is then heated and compressed at a pressure of 5 MPa for 10 minutes. The thermosetting resin powder melts due to heating and is impregnated into the fiber matrix of each layer due to the compression of the pre-molding laminate. Curing is completed in contact with the core material, thereby producing the fiber-reinforced sandwich composite of Example 1D, in which the fiber matrix and core material are laminated and integrated due to the curing of the thermosetting resin.

[0577] The product of the fiber-reinforced sandwich composite of Example 1D has an appearance of "○" and a density of 0.24 g / cm³. 3 It has a flexural strength of 23 MPa, a flexural modulus of 6.2 GPa, good appearance, high strength and rigidity, and is lightweight.

[0578] Example 2D

[0579] Except that resin B3 was used as the powder of the thermosetting resin, the fiber-reinforced sandwich composite of Example 2D was prepared in the same manner as in Example 1D.

[0580] Resin B3 is a phenolic resin manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-310, with an average particle size of 30μm.

[0581] The fiber-reinforced sandwich composite of Example 2D has an appearance of "○" and a density of 0.26 g / cm³. 3 It has a flexural strength of 19 MPa, a flexural modulus of 4.3 GPa, a good appearance, high strength and rigidity, and is lightweight.

[0582] Example 3D

[0583] As a thermosetting resin powder, 25g of resin (in which 12.5g of resin A3 and 12.5g of resin C3 are uniformly mixed) was used. The mold temperature was set to 170°C. Otherwise, the fiber-reinforced sandwich composite of Example 3D was made in the same manner as in Example 1D.

[0584] Resin C3 is produced by pulverizing epoxy resin manufactured by Mitsubishi Chemical Corporation, product name: jER-1001, using a mortar and pestle. The average particle size is 100 μm.

[0585] The fiber-reinforced sandwich composite of Example 3D has an appearance of "○" and a density of 0.23 g / cm³. 3 It has a flexural strength of 24 MPa, a flexural modulus of 6.8 GPa, a good appearance, high strength and rigidity, and is lightweight.

[0586] Example 4D

[0587] As the powder of thermosetting resin, 25g of resin (in which 12.5g or less of resin D3 and 12.5g or less of resin E3 are uniformly mixed) is used, and the mold temperature is set to 160°C. Otherwise, the fiber-reinforced sandwich composite of Example 4D is made in the same manner as in Example 1D.

[0588] Resin D3 is produced by pulverizing phenolic resin (product name: PR-50235D) manufactured by Sumitomo Bakelite Co., Ltd. using a mortar. The average particle size is 90 μm.

[0589] Resin E3 is produced by pulverizing cyanate ester resin manufactured by Mitsubishi Gas Chemical Co., Ltd., under the product name CYTESTER TA, using a mortar. The average particle size is 100 μm.

[0590] The fiber-reinforced sandwich composite of Example 4D has an appearance of "○" and a density of 0.26 g / cm³. 3 It has a flexural strength of 30MPa, a flexural modulus of 7.5GPa, a good appearance, high strength and rigidity, and is lightweight.

[0591] Fabrication of Example 5D

[0592] As the thermosetting resin powder, 24.9g of resin (8.3g of resin D3, 8.3g of resin E3 and 8.3g of resin C3) was used, and the mold temperature was set to 170°C. Otherwise, the fiber-reinforced sandwich composite of Example 5D was made in the same manner as in Example 1D.

[0593] The fiber-reinforced sandwich composite of Example 5D has an appearance of "○" and a density of 0.28 g / cm³. 3 It has a flexural strength of 28 MPa, a flexural modulus of 7.2 GPa, a good appearance, high strength and rigidity, and is lightweight.

[0594] Example 6D

[0595] Except that the fiber-reinforced sandwich composite of Example 6D was made in the same manner as in Example 1D, except that it used polymethacrylimide foam (manufactured by Evonik Industries, product name: Rohacell (IG-31)) with an independent bubble structure as the core material.

[0596] The fiber-reinforced sandwich composite of Example 6D has an appearance of "○" and a density of 0.38 g / cm³. 3 It has a flexural strength of 41 MPa, a flexural modulus of 14.3 GPa, a good appearance, high strength and rigidity, and is lightweight.

[0597] Example 7D

[0598] Except that the fiber-reinforced sandwich composite of Example 7D was made in the same manner as in Example 1D, except that it used polyvinyl chloride foam (manufactured by GURIT, product name: CoreCell (HT-80)) with an independent bubble structure as the core material.

[0599] The fiber-reinforced sandwich composite of Example 7D has an appearance of "○" and a density of 0.25 g / cm³. 3 It has a flexural strength of 26 MPa, a flexural modulus of 5.7 GPa, a good appearance, high strength and rigidity, and is lightweight.

[0600] Comparative Example 1D

[0601] Except that rigid polyurethane foam (manufactured by INOAC CORPORATION, product name: THERMAX(SII-25)) was used as the core material, the fiber-reinforced sandwich composite of Comparative Example 1D was prepared in the same manner as in Example 1D.

[0602] The fiber-reinforced sandwich composite of Comparative Example 1D has an appearance of "○" and a density of 0.21 g / cm³. 3 The flexural strength is 5 MPa and the flexural modulus is 0.6 GPa. Due to the low 5% compressive strength of the core material used, the strength of the fiber-reinforced sandwich composite is insufficient.

[0603] Comparative Example 2D

[0604] The following resin F3 was used as the powder of the thermosetting resin, and the mold temperature was set to 100°C. Otherwise, the fiber-reinforced sandwich composite of Comparative Example 2D was made in the same manner as in Example 1D.

[0605] Resin F3 is a phenolic resin manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50699, with an average particle size of 30μm.

[0606] Figure 24 The graph shows the viscosity measurement results of resin F3 (Comparative Example 2D).

[0607] Comparative Example 2D, due to the high viscosity (fast reaction) of the thermosetting resin, has poor impregnation of the fiber substrate, thus it is impossible to obtain a uniform fiber-reinforced sandwich composite, and it is impossible to measure the density, thickness, flexural strength and flexural modulus.

[0608] Comparative Example 3D

[0609] The resin (24.9g) of which was uniformly mixed with 8.3g of resin A3 and 16.6g of resin D3 was used as the powder of thermosetting resin, and the mold temperature was set to 160°C. Otherwise, the fiber-reinforced sandwich composite of Comparative Example 3D was made in the same manner as in Example 1D.

[0610] Figure 24 The graph shows the viscosity measurement results for resin A3 / resin D3 = 1 / 2 (comparative example 3D).

[0611] In Comparative Example 3D, due to insufficient curing of the thermosetting resin, the fiber-reinforced sandwich composite deformed during demolding, making it impossible to determine its density, thickness, flexural strength, and flexural modulus.

[0612] Thus, according to this method, since there is no need to use prepreg, no need for solvents for liquid thermosetting resins, no concern about environmental pollution, and no issue with the shelf life of thermosetting resins, it is possible to obtain fiber-reinforced sandwich composites that can be manufactured simply, cheaply, and safely without concern for environmental pollution.

[0613] This form is not limited to the embodiments, and changes can be made without departing from the spirit.

[0614] <Fifth Form>

[0615] The implementation method of the fifth form will be described. Figure 25 The fiber-reinforced molded body 410 shown in the first embodiment is integrally formed by laminating a core material 411 in which a thermosetting resin has been impregnated and cured in a resin foam and a fiber reinforcing material 415 in which a thermosetting resin has been impregnated and cured in a fiber matrix, and is obtained by the manufacturing method of the fiber-reinforced molded body of the present invention. The thermosetting resin impregnated and cured in the resin foam and the thermosetting resin impregnated and cured in the fiber matrix are common thermosetting resins.

[0616] Furthermore, to prevent warping of the fiber-reinforced molded body 410, it is preferable that fiber reinforcing material 415 is laminated on both sides of the core material 411. The number of layers of fiber reinforcing material 415 is not limited to one layer on each side of the core material 411, but may be two or more layers. In addition, the number of layers of fiber reinforcing material 415 on the two sides of the core material 411 may also be different.

[0617] The resin foam uses a resin foam with a continuous bubble structure. In this invention, a resin foam with a continuous bubble structure refers to a resin foam that primarily has a continuous bubble structure, not a resin foam that only slightly exhibits a continuous bubble structure.

[0618] There are no particular limitations on the resin foam having a continuous bubble structure, but thermosetting resin foams with a continuous bubble structure are preferred, such as urethane resin foams or melamine resin foams. When flame retardancy is required for the fiber-reinforced molded body 410, flame-retardant resin foams with a continuous bubble structure are preferred, and melamine resin foams are even more preferred.

[0619] As the fiber substrate, there are no particular limitations on fabrics or nonwovens made of glass fiber, polyaramid fiber, basalt fiber, carbon fiber, etc. Carbon fiber fabrics are preferred due to their excellent lightweight and high rigidity. As for carbon fiber fabrics, fabrics made with a weave pattern where the fibers are not unidirectional are preferred; for example, plain weave fabrics, twill weave fabrics, satin weave fabrics composed of warp and weft yarns, and triaxial fabrics composed of yarns in three directions are preferred. Furthermore, from the viewpoint of thermosetting resin impregnation and the rigidity of the fiber-reinforced molded body 410, a unit weight (fiber weight) of 50–600 g / m² is preferred for the carbon fiber fabric. 2 .

[0620] Preferably, the viscosity of the thermosetting resin impregnated and cured in the resin foam having a continuous bubble structure and the fiber substrate at the curing reaction start temperature Tb°C is 2000 Pa·s or less, more preferably 1500 Pa·s or less. By setting the viscosity at the curing reaction start temperature Tb°C to this range, when manufacturing the fiber-reinforced molded body 410, the molten thermosetting resin 419 can be fully impregnated in the resin foam having a continuous bubble structure and the fiber substrate, resulting in a fiber-reinforced molded body 410 with uniform physical properties. The thermosetting resin will be described in further detail in the manufacturing method of the fiber-reinforced molded body 410 described later.

[0621] The preferred fiber-reinforced molded body 410 has a flexural modulus (JIS K7074 A method) of 24 GPa or more, and more preferably 30 GPa or more.

[0622] The preferred fiber-reinforced molded body 410 has a flexural strength (JIS K7074 A method) of 300 MPa or more, and more preferably 380 MPa or more.

[0623] Figure 26 This is a diagram illustrating one embodiment of a method for manufacturing a fiber-reinforced molded body 410. Furthermore, in the following description of the manufacturing method, when components with the same name are arranged in multiple positions, their vertical positional relationship is sometimes indicated by a combination of numbers and letters, such as "417A".

[0624] exist Figure 26In the embodiment shown, a resin foam 413 with a continuous bubble structure is disposed on a fiber substrate 417A, a powdered thermosetting resin 419 is disposed on it, and a fiber substrate 417B is disposed on it to form a pre-molding laminate.

[0625] Furthermore, there is no limitation on the location and number of locations where the powdered thermosetting resin 419 is disposed, but it is preferred to be disposed at a location that is at least in contact with the resin foam 413.

[0626] The pre-molded laminate, formed by clamping the lower mold 461 and upper mold 462 of a heated mold 460, is then subjected to heating and compression. The mold 460 is heated to the temperature Tc℃ required for heating and compression by a heating unit such as an electric heater.

[0627] The powdered thermosetting resin 419 used in the manufacturing method of the fiber-reinforced molded body 410 is the thermosetting resin described in the fiber-reinforced molded body 410 above. Preferably, its viscosity at the curing reaction start temperature Tb°C is 2000 Pa·s or less, more preferably 1500 Pa·s or less. By setting the viscosity at the curing reaction start temperature Tb°C to this range, the molten thermosetting resin 419 can be fully impregnated in the resin foam 413 having a continuous bubble structure and the fiber substrates 417A and 417B, thereby obtaining a fiber-reinforced molded body 410 with uniform physical properties.

[0628] Furthermore, the thermosetting resin 419 preferably has a maximum viscosity of 1000 Pa·s or higher within a temperature range of Tb℃ to 190℃ during the curing reaction. By setting the maximum viscosity within this range, when manufacturing the fiber-reinforced molded body 410, the molten thermosetting resin 419 can be fully impregnated in the resin foam 413 with a continuous bubble structure and the fiber substrates 417A and 417B, resulting in good shapeability of the fiber-reinforced molded body 410 and the ability to obtain sufficient strength in a short time.

[0629] In the relationship between the melting start temperature Ta℃ and the curing reaction start temperature Tb℃ of thermosetting resin 419 and the temperature Tc℃ during heating and compression...

[0630] The preferred setting is [Tb+(Tb-Ta) / 3]-15≤Tc≤[Tb+(Tb-Ta) / 3]+20.

[0631] More preferably, [Tb+(Tb-Ta) / 3]-10≤Tc≤[Tb+(Tb-Ta) / 3]+20. By making the melting start temperature Ta℃, the curing reaction start temperature Tb℃, and the temperature Tc℃ during heating and compression of the thermosetting resin in this relationship, the thermosetting resin 419 melts well during heating and compression, and the thermosetting resin 419 is easily impregnated into the resin foam 413 with a continuous bubble structure and the fiber substrates 417A and 417B, thereby obtaining a fiber-reinforced molded body 410 with uniform physical properties.

[0632] Preferably, the value of the curing reaction start temperature Tb℃ - melting start temperature Ta℃ of the thermosetting resin 419 is 30≤(Tb-Ta)≤100, more preferably 40≤(Tb-Ta)≤70. By setting (Tb-Ta) within this range, the molten thermosetting resin 419 can be fully impregnated in the resin foam 413 with a continuous bubble structure and the fiber substrates 417A and 417B, resulting in a fiber-reinforced molded body 410 with uniform physical properties.

[0633] The preferred melting point Ta of thermosetting resin 419 is 60–100°C. By setting the melting point Ta of thermosetting resin 419 within this range, temperature adjustment during heating and compression can be easily achieved.

[0634] For thermosetting resins that satisfy the above-mentioned melting start temperature Ta℃, curing reaction start temperature Tb℃, (Tb-Ta) range, viscosity at curing reaction start temperature Tb℃, and maximum viscosity, resins selected from the group consisting of phenolic resins, mixtures of phenolic resins and epoxy resins, mixtures of phenolic resins and cyanate ester resins, and mixtures of phenolic resins, cyanate ester resins, and epoxy resins are preferred. Phenolic resins, due to their excellent flame retardancy, can impart excellent strength and flame retardancy to fiber-reinforced molded articles.

[0635] Furthermore, various powder additives such as pigments, antibacterial agents, and ultraviolet absorbers can be added to the thermosetting resin 419, provided that they do not affect the viscosity or reactivity of the thermosetting resin. The powder shape of the thermosetting resin 419 can be spherical, needle-like, or fragmented, and is not particularly limited. From the viewpoint of easy melting, a particle size of 10–500 μm is preferred for the powdered thermosetting resin 419.

[0636] For the amount of thermosetting resin 419, the resin ratio specified by formula (A1) is preferably 50% to 80%. By setting the resin ratio within this range, the fiber-reinforced molded body 410 can be made into a high-strength molded body.

[0637] [Formula 3]

[0638] (A1)

[0639]

[0640] In order for the thermosetting resin 419 to be well impregnated in the resin foam 413 and fiber substrates 417A and 417B having a continuous bubble structure after melting, the pressure (compression) of the laminate before molding during the heating compression performed by the mold 460 is preferably 2 to 20 MPa. Furthermore, for the compression of the laminate before molding, it is preferable to set the compression rate as specified by formula (A2) to be 200 to 5000%. By setting the compression rate within this range, the fiber-reinforced molded body 410 can be made into a high-strength molded body.

[0641] [Formula 4]

[0642] (A2)

[0643]

[0644] When the pre-molding laminate is heated and compressed using mold 460, the thermosetting resin 419 melts due to the heating of the pre-molding laminate by mold 460. The molten thermosetting resin is impregnated in the resin foam 413 with a continuous bubble structure and the fiber substrates 417A and 417B by the compression of the pre-molding laminate by mold 460. Then, the thermosetting resin 419 impregnated in the resin foam 413 with a continuous bubble structure and the fiber substrates 417A and 417B is cured, so that the resin foam 413 with a continuous bubble structure between the fiber substrates 417A and 417B is shaped and bonded together under compressed conditions, resulting in the mold surface shape of the lower mold 461 and the upper mold 462. Figure 25 Fiber-reinforced molded body 410.

[0645] exist Figure 26 In the embodiment of the manufacturing method shown, the powdered thermosetting resin 419 is disposed only on one side (single side) of the resin foam 413 having a continuous bubble structure, but it can also be disposed on both sides of the resin foam 413 to manufacture the fiber-reinforced molded body 410.

[0646] Figure 27 This invention illustrates one embodiment of manufacturing a fiber-reinforced molded body 410 by distributing powdered thermosetting resin 419 on both sides of a resin foam 413.

[0647] exist Figure 27 In the embodiment shown, a pre-molding laminate is formed by depositing a powdered thermosetting resin 419A on a fiber substrate 417A, depositing a resin foam 413 with a continuous bubble structure on it, depositing a powdered thermosetting resin 419B on it, and then depositing a fiber substrate 417B on it.

[0648] The pre-molding laminate, formed by clamping the lower mold 461 and upper mold 462 of the heated mold 460, is heated and compressed to obtain a mold surface shape that conforms to the shape of the lower mold 461 and upper mold 462. Figure 25 Fiber-reinforced molded body 410. Manufacturing conditions including resin foam 413 with a continuous bubble structure, fiber substrates 417A and 417B, powdered thermosetting resins 419A and 419B, resin ratios, heating, compression, etc. Figure 26 As described in the manufacturing implementation method.

[0649] Figure 28 The fiber-reinforced molded body 420 shown in the second embodiment is a case in which two layers (two sheets) of fiber reinforcing material 415 are stacked on both sides of the core material 411. The core material 411 and the fiber reinforcing material 415 are as described in the fiber-reinforced molded body 410 of the first embodiment.

[0650] Furthermore, in fiber-reinforced molded articles where the fiber-reinforced material 415 has two or more layers, a flexural modulus of elasticity (JIS K7074 A method) of 24 GPa or higher is preferred, and 30 GPa or higher is more preferred. Additionally, a flexural strength (JIS K7074 A method) of 300 MPa or higher is preferred, and 380 MPa or higher is more preferred.

[0651] The manufacturing method of the fiber-reinforced molded body 420 according to the second embodiment will be explained. Figure 29 One embodiment is shown.

[0652] exist Figure 29 In the embodiment shown, two fiber substrates 417A and 417B are stacked, a resin foam 413 with a continuous bubble structure is disposed on it, and a powdered thermosetting resin 419 is disposed on it. Then, two fiber substrates 417C and 417D are stacked on it to form a pre-molding laminate.

[0653] The pre-molding laminate, formed by clamping the lower mold 461 and upper mold 462 of the heated mold 460, is heated and compressed to obtain a mold surface shape that conforms to the shape of the lower mold 461 and upper mold 462. Figure 28 The fiber-reinforced molded body 420. The mold 460 is heated to the temperature Tc℃ required for heat compression by a heating unit such as an electric heater. Manufacturing conditions such as the resin foam 413 with a continuous bubble structure, fiber substrates 417A to 417D, powdered thermosetting resin 419A, resin ratio, heating, and compression are as follows. Figure 26 As described in the manufacturing implementation method.

[0654] right Figure 30The fiber-reinforced molded body 430 of the third embodiment will be described below. The fiber-reinforced molded body 430 of the third embodiment is integrally formed by laminating a core material 411 impregnated and cured with thermosetting resin in a resin foam and a fiber reinforcing material 415 impregnated and cured with thermosetting resin in a fiber matrix. Recesses 431 and protrusions 433 are formed on the surface of the fiber-reinforced molded body 430. In the fiber-reinforced molded body 430 of the third embodiment, except for the formation of recesses 431 and protrusions 433, the structure is the same as that of the fiber-reinforced molded body 410 of the first embodiment. In fiber-reinforced molded bodies with an uneven surface, a flexural modulus of elasticity (JIS K7074 A method) of 24 GPa or more is preferred, and 30 GPa or more is more preferred. Furthermore, a flexural strength (JIS K7074 A method) of 300 MPa or more is preferred, and 380 MPa or more is more preferred.

[0655] The concave shape of the recess 431 and the convex shape 433 is not particularly limited as long as the compression rate specified by the above formula (A2) is within the range of 200 to 5000%. For example, the depth, height, and planar shape (straight or curved) are appropriately determined according to the application of the fiber-reinforced molded body 430. In addition, the concave and convex shapes are not limited to one side of the fiber-reinforced molded body, but can also be provided on both sides.

[0656] The manufacturing method of the fiber-reinforced molded body 430 of the third embodiment, which has a surface with irregularities, is explained. Figure 31 One embodiment is shown.

[0657] exist Figure 31 In the manufacturing method of the embodiment shown, a resin foam 413 having a continuous bubble structure is disposed on a fiber substrate 417A, a powdered thermosetting resin 419 is disposed on it, and then a fiber substrate 417B is disposed on it to form a pre-molding laminate.

[0658] The pre-molded laminate is clamped by the lower mold 471 of the heated mold 470 and the upper mold 472, which has recess-forming protrusions 473 and convex-forming grooves 475 formed on its surface, and then heated and compressed. The recess-forming protrusions 473 form the recesses 431 of the fiber-reinforced molded body 430, and the convex-forming grooves 475 form the convexities 433 of the fiber-reinforced molded body 430. The mold 470 is heated to the temperature Tc℃ required for heat compression by a heating unit such as an electric heater. Manufacturing conditions such as the resin foam 413 with a continuous bubble structure, fiber substrates 417A and 417B, powdered thermosetting resin 419, resin ratio, heating, and compression are as follows: Figure 26 As described in the manufacturing implementation method.

[0659] Before molding, the laminate is compressed by heating in mold 470 into a concave-convex shape corresponding to the mold surface of upper mold 472. Simultaneously, thermosetting resin 419 melts and impregnates resin foam 413 and fiber substrates 417A and 417B, which have a continuous bubble structure. Then, due to the curing of the impregnated thermosetting resin, a mold surface shape corresponding to the lower mold 471 and upper mold 472 is obtained. Figure 30 Fiber-reinforced molded body 430.

[0660] exist Figure 32 In the fiber-reinforced molded body 440 of the fourth embodiment shown, two layers (two sheets) of fiber reinforcing material 415 are stacked on both sides of the core material 411, and recesses 441 and protrusions 443 are formed on the surface of the fiber-reinforced molded body 440. In the fiber-reinforced molded body 440 of the fourth embodiment, except for the recesses 441 and protrusions 443, the rest is the same structure as the fiber-reinforced molded body 420 of the second embodiment.

[0661] Furthermore, even in fiber-reinforced molded articles with an uneven surface and two or more layers of fiber reinforcement material 415, a flexural modulus (JIS K7074 A method) of 24 GPa or higher is preferred, and 30 GPa or higher is more preferred. Additionally, a flexural strength (JIS K7074 A method) of 300 MPa or higher is preferred, and 380 MPa or higher is more preferred.

[0662] The manufacturing method of the fiber-reinforced molded body 440 of the fourth embodiment, in which an uneven surface is formed, is described below. Figure 33 One embodiment is shown.

[0663] exist Figure 33 In the manufacturing method of the embodiment shown, two fiber substrates 417A and 417B are stacked, a resin foam 413 with a continuous bubble structure is disposed on it, and a powdered thermosetting resin 419 is disposed on it. Then, two fiber substrates 417C and 417D are stacked on it to form a pre-molding laminate.

[0664] The pre-molded laminate is held in place by a lower mold 471 of a heated mold 470 and an upper mold 472, which has recess-forming protrusions 473 and convex-forming grooves 475 formed on its surface, and then subjected to heat compression. The recess-forming protrusions 473 are portions forming the recesses 441 of the fiber-reinforced molded body 440, and the convex-forming grooves 475 are portions forming the convex portions 443 of the fiber-reinforced molded body 440. The mold 470 is heated to the temperature Tc℃ required for heat compression by a heating unit such as an electric heater. The manufacturing conditions, including the resin foam 413 with a continuous bubble structure, fiber substrates 417A to 417D, powdered thermosetting resin 419, resin ratio, heating, and compression, are the same as those used in the method for manufacturing the fiber-reinforced molded body 420 of the second embodiment.

[0665] Before molding, the laminate is compressed by heating in mold 470 into a concave-convex shape corresponding to the mold surface of upper mold 472. Simultaneously, thermosetting resin 419 melts and impregnates resin foam 413 and fiber substrates 417A-417D, which have a continuous bubble structure. Then, due to the curing of the impregnated thermosetting resin, a mold surface shape corresponding to the lower mold 471 and upper mold 472 is obtained. Figure 32 Fiber-reinforced molded body 440.

[0666] Furthermore, in methods for manufacturing fiber-reinforced molded articles with uneven surfaces, the powdered thermosetting resin is not limited to one side of the resin foam with a continuous bubble structure, but can also be disposed on both sides. Figure 34 One embodiment of the manufacturing method for this situation is described.

[0667] Figure 34 The embodiments shown involve Figure 32 The manufacturing of the fiber-reinforced molded body 440 of the fourth embodiment, which has an uneven surface, is shown.

[0668] exist Figure 34 In one embodiment, two fiber substrates 417A and 417B are stacked, a powdered thermosetting resin 419A is disposed on them, a resin foam 413 with a continuous bubble structure is disposed on them, a powdered thermosetting resin 419B is disposed on them, and then two fiber substrates 417C and 417D are stacked on them to form a pre-molding laminate.

[0669] The pre-molding laminate is held in place by the lower mold 471 of the heated mold 470 and the upper mold 472, which has protrusions 473 for forming recesses and grooves 475 for forming convexities on its mold surface, and is then heated and compressed. The manufacturing conditions, including the resin foam 413 with a continuous bubble structure, fiber substrates 417A to 417D, powdered thermosetting resins 419A and 419B, resin ratios, heating, and compression, are as described above. Through the heating and compression of the pre-molding laminate by the mold 470, the thermosetting resins 419A and 419B melt and impregnate the resin foam 413 with a continuous bubble structure and the fiber substrates 417A to 417D. Then, due to the curing of the impregnated thermosetting resin, a mold surface shape shaped like the lower mold 471 and the upper mold 472 is obtained. Figure 32 Fiber-reinforced molded body 440.

[0670] <Example>

[0671] use Figure 35 The powdered thermosetting resin shown is used to make... Figure 36 The fiber-reinforced molded articles of the various embodiments and comparative examples shown.

[0672] The viscosity of thermosetting resins was measured using a Rheosol-G3000 rheometer manufactured by UBM Corporation under the following conditions.

[0673] 1) Take 0.4g of the sample and form it into granules (approximately φ18mm in diameter and 0.4mm in thickness). Clamp the formed granules onto a parallel plate with a diameter of φ18mm.

[0674] 2) Under the conditions of heating rate of 5℃ / min, frequency of 1Hz, rotation angle (strain) of 0.1deg and constant heating rate, the dynamic viscosity was measured at 2℃ intervals between 40℃ and 200℃.

[0675] exist Figure 35 In this context, the melting start temperature (Ta) represents the temperature at which the highest viscosity (the highest viscosity in the temperature range below the curing reaction start temperature (Tb)) is reached; the curing reaction start temperature (Tb) represents the temperature at which the lowest viscosity is reached; and the highest viscosity is the highest viscosity in the temperature range from the curing reaction start temperature (Tb) to 190°C.

[0676] For each embodiment and comparative example of fiber-reinforced molded body, the appearance of the product is judged, and the thickness of the molded body (general part, convex part, concave part), the thickness of the core material (general part, convex part, concave part), the compression ratio (general part, convex part, concave part), the specific gravity, the weight, the resin ratio, the flexural strength, and the flexural modulus are calculated or measured.

[0677] The appearance of the product is determined by visually inspecting the surface of the fiber-reinforced molded body to check for defects caused by deformation or uneven resin impregnation. Products without defects are rated as "○", and products with defects are rated as "×".

[0678] The compression ratio is calculated using the above formula (A2).

[0679] Specific gravity is calculated based on the weight and volume of the fiber-reinforced molded body. The volume of the fiber-reinforced molded body is calculated based on its thickness and area.

[0680] The resin ratio is calculated using the above formula (A1).

[0681] In addition, the weight of the fiber substrate and the resin foam with a continuous bubble structure before molding is calculated by the following formula.

[0682] Weight of fiber substrate = Unit weight × Area of ​​fiber-reinforced molded body × Number of fiber substrate sheets used

[0683] Weight of resin foam = density of resin foam × area of ​​fiber-reinforced molded body × thickness of resin foam before molding

[0684] The flexural strength and flexural modulus were determined according to JIS K7074 A method.

[0685] Example 1E

[0686] Examples 1E to 12E are Figure 25 The fiber-reinforced molded body 410 shown and Figure 26 Examples of manufacturing methods.

[0687] In Example 1E, two sheets of carbon fiber fabric (manufactured by Teijin Corporation, product name: W-3101, unit weight: 200g / m²) were prepared as the fiber substrate. 2 The substrate (0.22mm thick) was cut into 200mm × 300mm pieces. Each piece of fiber substrate weighed 12g after cutting. Additionally, as a resin foam with a continuous bubble structure, a melamine resin foam (manufactured by BASF, product name Basotect G+, density 9kg / m³) with a thickness of 10mm and a planar size of 200 × 300mm was prepared, to be cut into pieces with a density of 9kg / m³. 3 ).

[0688] Melamine foam is laminated on a fiber substrate, and 65.0g of resin A4 as a powder thermosetting resin is uniformly distributed on it. Then another fiber substrate is placed on it to make a pre-molding laminate.

[0689] Resin A4 is a phenolic resin manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50252, with an average particle size of 30μm.

[0690] Figure 37 The graphs show the viscosity measurement results of resin A4 (Examples 1E, 6E-15E, 20E-26E).

[0691] Next, a pre-molding laminate was placed on the molding surface of the lower mold of a mold heated to 150°C. The mold was then closed, and the laminate was heated and compressed at a pressure of 10 MPa for 10 minutes. The thermosetting resin melted due to heating and was subjected to pressure from the mold, thereby impregnating the thermosetting resin in each layer of the fiber substrate and resin foam, completing the curing reaction. This produced a fiber-reinforced molded body composed of a fiber reinforcing material impregnated and cured with thermosetting resin in a fiber substrate and a core material impregnated and cured with thermosetting resin in a resin foam having a continuous bubble structure. This fiber-reinforced molded body was cut to 170 × 260 mm as the fiber-reinforced molded body of Example 1.

[0692] In addition, a 1mm thick SUS spacer is placed between the lower and upper molds of the mold, the gap between the upper and lower molds is set to 1mm, and the compression thickness of the laminate before molding is adjusted to 1mm.

[0693] The numerical and physical property values ​​of the fiber-reinforced molded article in Example 1E are as follows: Figure 36 As shown. If we list the main numerical and physical properties, the compression ratio is 1686%, the specific gravity is 1.35, the resin ratio is 70%, the flexural strength is 500MPa, the flexural modulus is 45GPa, the product appearance is "○", the appearance is good, the strength and rigidity are high, and it is lightweight.

[0694] Example 2E

[0695] Except that resin B4 was used as a powdered thermosetting resin, the fiber-reinforced molded body of Example 2E was made in the same manner as in Example 1E.

[0696] Resin B4 is a phenolic resin manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-310, with an average particle size of 30μm.

[0697] The fiber-reinforced molded part of Example 2E has a compression rate of 1686%, a specific gravity of 1.34, a resin ratio of 70%, a flexural strength of 400 MPa, a flexural modulus of 40 GPa, and an appearance of "○". It has a good appearance, high strength and rigidity, and is lightweight.

[0698] Example 3E

[0699] As a powdered thermosetting resin, resin A4 and resin C4 were uniformly mixed in a 1:1 weight ratio, and the mold temperature was set to 170°C. Otherwise, the fiber-reinforced molded body of Example 3E was made in the same manner as in Example 1E.

[0700] Resin C4 is produced by pulverizing epoxy resin manufactured by Mitsubishi Chemical Corporation, product name: jER-1001, using a mortar and pestle. The average particle size is 100 μm.

[0701] The fiber-reinforced molded part of Example 3E has a compression rate of 1686%, a specific gravity of 1.35, a resin ratio of 70%, a flexural strength of 820 MPa, a flexural modulus of elasticity of 50 GPa, and an appearance of "○". It has a good appearance, high strength and rigidity, and is lightweight.

[0702] Example 4E

[0703] As a powdered thermosetting resin, a resin in which resin D4 and resin E4 are uniformly mixed in a 1:1 weight ratio is used, and the mold temperature is set to 160°C. Otherwise, the fiber-reinforced molded body of Example 4E is made in the same manner as in Example 1E.

[0704] Resin D4 is used by pulverizing phenolic resin (product name: PR-50235D) manufactured by Sumitomo Bakelite Co., Ltd. using a mortar. The average particle size is 90 μm.

[0705] Resin E4 is produced by pulverizing cyanate ester resin manufactured by Mitsubishi Gas Chemical Co., Ltd., under the product name CYTESTER TA, using a mortar and pestle. The average particle size is 100 μm.

[0706] The fiber-reinforced molded part of Example 4E has a compression rate of 1686%, a specific gravity of 1.35, a resin ratio of 70%, a flexural strength of 850 MPa, a flexural modulus of elasticity of 52 GPa, and an appearance of "○". It has a good appearance, high strength and rigidity, and is lightweight.

[0707] Example 5E

[0708] As a powdered thermosetting resin, resin D4, resin E4 and resin C4 were uniformly mixed in a weight ratio of 1:1:1, and the mold temperature was set to 170°C. Otherwise, the fiber-reinforced molded body of Example 5E was made in the same manner as in Example 1E.

[0709] The fiber-reinforced molded part of Example 5E has a compression rate of 1686%, a specific gravity of 1.35, a resin ratio of 70%, a flexural strength of 860 MPa, a flexural modulus of elasticity of 53 GPa, and an appearance of "○". It has a good appearance, high strength and rigidity, and is lightweight.

[0710] Example 6E

[0711] In addition to using melamine resin foam (manufactured by BASF, product name Basotect G+, density 9 kg / m³) cut to a thickness of 6 mm and a planar size of 200 × 300 mm (weight 3.2 g), 3 In addition to being a resin foam with a continuous bubble structure, the fiber-reinforced molded body of Example 6E was made in the same manner as Example 1E.

[0712] The fiber-reinforced molded part of Example 6E has a compression rate of 971%, a specific gravity of 1.35, a resin ratio of 70%, a flexural strength of 510 MPa, a flexural modulus of elasticity of 46 GPa, and an appearance of "○". It has a good appearance, high strength and rigidity, and is lightweight.

[0713] Example 7E

[0714] In addition to using melamine resin foam (manufactured by BASF, brand name Basotect G+, density 9 kg / m³) cut to a thickness of 2 mm and a planar size of 200 × 300 mm (weight 1.1 g), 3 In addition to being a resin foam with a continuous bubble structure, the fiber-reinforced molded body of Example 7E was made in the same manner as Example 1E.

[0715] The fiber-reinforced molded body of Example 7E has a compression rate of 257%, a specific gravity of 1.35, a resin ratio of 70%, a flexural strength of 420 MPa, a flexural modulus of 40 GPa, and an appearance of "○". It has a good appearance, high strength and rigidity, and is lightweight.

[0716] Example 8E

[0717] In addition to using melamine resin foam (manufactured by BASF, brand name Basotect G+, density 9 kg / m³) cut to a thickness of 20 mm and a planar size of 200 × 300 mm (weight 10.8 g), 3 In addition to being a resin foam with a continuous bubble structure, the fiber-reinforced molded body of Example 8E was made in the same manner as Example 1E.

[0718] The fiber-reinforced molded part of Example 8E has a compression rate of 3471%, a specific gravity of 1.36, a resin ratio of 71%, a flexural strength of 450 MPa, a flexural modulus of 42 GPa, and an appearance of "○". It has a good appearance, high strength and rigidity, and is lightweight.

[0719] Example 9E

[0720] In addition to using melamine resin foam (manufactured by BASF, brand name Basotect G+, density 9 kg / m³) cut to a thickness of 28 mm and a planar size of 200 × 300 mm (weight 15.1 g), 3 In addition to being a resin foam with a continuous bubble structure, the fiber-reinforced molded body of Example 9E was made in the same manner as Example 1E.

[0721] The fiber-reinforced molded part of Example 9E has a compression rate of 4900%, a specific gravity of 1.36, a resin ratio of 71%, a flexural strength of 400 MPa, a flexural modulus of 39 GPa, and an appearance of "○". It has a good appearance, high strength and rigidity, and is lightweight.

[0722] Example 10E

[0723] Except that 48g of resin A was used as a powdered thermosetting resin, the fiber-reinforced molded body of Example 10E was prepared in the same manner as in Example 1E.

[0724] The fiber-reinforced molded body of Example 10E has a compression rate of 2074%, a specific gravity of 1.35, a resin ratio of 53%, a flexural strength of 410 MPa, a flexural modulus of 43 GPa, and an appearance of "○". It has a good appearance, high strength and rigidity, and is lightweight.

[0725] Example 11E

[0726] Except that 70g of resin A was used as a powdered thermosetting resin, the fiber-reinforced molded body of Example 11E was prepared in the same manner as in Example 1E.

[0727] The fiber-reinforced molded body of Example 11E has a compression rate of 1415%, a specific gravity of 1.37, a resin ratio of 76%, a flexural strength of 400 MPa, a flexural modulus of elasticity of 42 GPa, and an appearance of "○". It has a good appearance, high strength and rigidity, and is lightweight.

[0728] Example 12E

[0729] In addition to using urethane resin foam (manufactured by INOAC CORPORATION, product name: MF-50, density 30kg / m³) cut to a thickness of 10mm and a flat size of 200×300mm, the foam is made of 18g (10mm thick). 3 In addition to being a resin foam with a continuous bubble structure, the fiber-reinforced molded body of Example 12E was made in the same manner as Example 1E.

[0730] The fiber-reinforced molded body of Example 12E has a compression rate of 1686%, a specific gravity of 1.35, a resin ratio of 70%, a flexural strength of 450 MPa, a flexural modulus of 40 GPa, and an appearance of "○". It has a good appearance, high strength and rigidity, and is lightweight.

[0731] Example 13E

[0732] Example 13E involves placing powdered thermosetting resin on both sides of a resin foam having a continuous bubble structure. Figure 25 The fiber-reinforced molded body 410 shown and Figure 27 Examples of manufacturing methods.

[0733] Except that 32.5g of resin A4 as a powdered thermosetting resin was generally uniformly distributed above and below the melamine resin foam, the fiber-reinforced molded body of Example 13E was prepared in the same manner as Example 1E.

[0734] The fiber-reinforced molded part of Example 13E has a compression rate of 1686%, a specific gravity of 1.35, a resin ratio of 70%, a flexural strength of 500 MPa, a flexural modulus of 44 GPa, and an appearance of "○". It has a good appearance, high strength and rigidity, and is lightweight.

[0735] Example 14E

[0736] Example 14E involves placing two fiber substrates on each side of a resin foam with a continuous bubble structure. Figure 28 The fiber-reinforced molded body 420 shown and Figure 29 Examples of manufacturing methods.

[0737] As the fiber substrate, prepare 4 pieces (each piece of fiber substrate weighs 12g after cutting) of carbon fiber fabric (manufactured by Teijin Corporation, product name: W-3101, unit weight: 200g / m²). 2 A substrate (0.22 mm thick) was cut into 200 mm × 300 mm pieces. A melamine resin foam was placed on two stacked fiber substrates. 57.0 g of resin A4 as a powdered thermosetting resin was placed on the foam, and the remaining two fiber substrates were placed on top of the foam. A 1.5 mm thick SUS spacer was placed between the lower and upper molds of the mold. Otherwise, the fiber-reinforced molded body of Example 14E was made in the same manner as in Example 1E.

[0738] The fiber-reinforced molded part of Example 14E has a compression rate of 1513%, a specific gravity of 1.40, a resin ratio of 62%, a flexural strength of 550 MPa, a flexural modulus of elasticity of 48 GPa, and an appearance of "○". It has a good appearance, high strength and rigidity, and is lightweight.

[0739] Example 15E

[0740] Examples 15E to 19E and Example 22E are Figure 30 The surface shown is formed with an uneven fiber-reinforced molded body 430 (one fiber reinforcement layer on each side of the core material) and Figure 31 Examples of manufacturing methods.

[0741] In Example 15E, two sheets of carbon fiber fabric (manufactured by Teijin Corporation, product name: W-3101, unit weight: 200g / m²) were prepared as the fiber substrate. 2 The substrate (0.22mm thick) was cut into 200mm × 300mm pieces. Each piece of fiber substrate weighed 12g after cutting. Additionally, as a resin foam with a continuous bubble structure, a melamine resin foam (manufactured by BASF, brand name Basotect G+, density 9kg / m³) with a thickness of 10mm and a planar size of 200 × 300mm was prepared, to be cut into pieces with a density of 9kg / m³. 3 ).

[0742] Melamine resin foam is laminated on a fiber substrate, and 65.0g of resin A4 as a powder thermosetting resin is roughly uniformly distributed on it. Then, another fiber substrate is placed on it to form a pre-molding laminate.

[0743] Next, a pre-molding laminate is placed on the molding surface of the lower mold of the mold that has been heated to 150°C, and then the upper mold is overlapped and the mold is closed. The mold is then heated and compressed for 10 minutes at a pressure of 10 MPa.

[0744] On the upper mold surface of the mold, protrusions (1 mm high and 10 mm wide) for forming recesses and grooves (0.5 mm deep and 10 mm wide) for forming convex parts are formed at intervals of 100 mm from one end of the mold surface to the other.

[0745] Place a 1mm thick SUS spacer between the lower and upper molds, set the gap between the lower and upper molds to 1mm, and adjust the compression thickness of the laminate before molding to 1mm.

[0746] Thermosetting resin melts during heating and compression, and pressure generated by a mold is applied, thereby impregnating the fiber substrate and resin foam layers with the thermosetting resin, completing the curing reaction. This produces a fiber-reinforced molded body composed of a fiber reinforcing material impregnated and cured with thermosetting resin in a fiber substrate, and a core material impregnated and cured with thermosetting resin in a resin foam having a continuous bubble structure. One side of the fiber-reinforced molded body has a recess shaped by a protrusion formed by a recess in the upper mold, and a protrusion shaped by a groove formed by a convex portion. This fiber-reinforced molded body was cut to 170 × 260 mm as the fiber-reinforced molded body of Example 15E.

[0747] The numerical and physical property values ​​of the fiber-reinforced molded article of Example 15E are as follows: Figure 36 As shown. If the main numerical values ​​and physical properties are given, the compression ratio is 1329% for the unremarkable general portion with a thickness of 1.0 mm; 413% for the convex portion with a thickness of 2.0 mm; and 4900% for the concave portion with a thickness of 0.6 mm. The overall specific gravity is 1.35, the resin content is 70%, the flexural strength is 500 MPa, the flexural modulus is 46 GPa, and the product has an "○" appearance, indicating good appearance, high strength and rigidity, and lightweight. The flexural strength and flexural modulus were measured for the unremarkable general portion.

[0748] Example 16E

[0749] Except that resin B4 was used as a powdered thermosetting resin, the fiber-reinforced molded body of Example 16E was made in the same manner as Example 15E.

[0750] In the fiber-reinforced molded body of Example 16E, the thickness of the unremarkable general portion is 1.0 mm, and the compression ratio is 1329%; the thickness of the convex portion is 2.0 mm, and the compression ratio is 413%; the thickness of the concave portion is 0.6 mm, and the compression ratio is 4900%; the overall specific gravity is 1.34, the resin ratio is 70%, the flexural strength is 410 MPa, the flexural modulus is 40 GPa, the product appearance is “○”, the appearance is good, the strength and rigidity are high, and the weight is light.

[0751] Example 17E

[0752] The resin used was a powdered thermosetting resin in which resin A4 and resin C4 were uniformly mixed in a weight ratio of 1:1, and the mold temperature was set to 170°C. Otherwise, the fiber-reinforced molded body of Example 17E was made in the same manner as in Example 15E.

[0753] In the fiber-reinforced molded body of Example 17E, the thickness of the unremarkable general portion is 1.0 mm, and the compression ratio is 1329%; the thickness of the convex portion is 2.0 mm, and the compression ratio is 413%; the thickness of the concave portion is 0.6 mm, and the compression ratio is 4900%; the overall specific gravity is 1.35, the resin ratio is 70%, the flexural strength is 820 MPa, the flexural elasticity is 51 GPa, the product appearance is “○”, indicating good appearance, high strength and rigidity, and lightweight.

[0754] Example 18E

[0755] As a powdered thermosetting resin, resin D4 and resin E4 were uniformly mixed in a weight ratio of 1:1, and the mold temperature was set to 160°C. Otherwise, the fiber-reinforced molded body of Example 18E was made in the same manner as in Example 15E.

[0756] In the fiber-reinforced molded body of Example 18E, the thickness of the unremarkable general portion is 1.0 mm, and the compression ratio is 1329%; the thickness of the convex portion is 2.0 mm, and the compression ratio is 413%; the thickness of the concave portion is 0.6 mm, and the compression ratio is 4900%; the overall specific gravity is 1.35, the resin ratio is 70%, the flexural strength is 860 MPa, the flexural elasticity is 52 GPa, the product appearance is “○”, indicating good appearance, high strength and rigidity, and lightweight.

[0757] Example 19E

[0758] As a powdered thermosetting resin, resin D4, resin E4 and resin C4 were uniformly mixed in a weight ratio of 1:1:1, and the mold temperature was set to 170°C. Otherwise, the fiber-reinforced molded body of Example 19E was made in the same manner as in Example 15E.

[0759] In the fiber-reinforced molded body of Example 19E, the thickness of the unremarkable general portion is 1.0 mm, and the compression ratio is 1329%; the thickness of the protruding portion is 2.0 mm, and the compression ratio is 413%; the thickness of the concave portion is 0.6 mm, and the compression ratio is 4900%; the overall specific gravity is 1.35, the resin ratio is 70%, the flexural strength is 850 MPa, the flexural modulus is 53 GPa, the product appearance is "○", it has a good appearance, high strength and rigidity, and is lightweight.

[0760] Example 20E

[0761] Example 20E is Figure 32 The fiber-reinforced molded body 440 shown has an uneven surface (two fiber reinforcement layers on each side of the core material) and Figure 33 Examples of manufacturing methods.

[0762] Prepare four fiber substrates identical to those in Example 15E. On two of the stacked fiber substrates, stack a resin foam with a continuous bubble structure identical to that in Example 15E. On this foam, 57.0g of resin A4 as a powdered thermosetting resin is disposed approximately uniformly. The remaining two fiber substrates are then disposed on top of this foam to form a pre-molding laminate. A spacer made of SUS with a thickness of 1.5mm is used. Otherwise, the fiber-reinforced molded body of Example 20E is made in the same manner as in Example 15E.

[0763] In the fiber-reinforced molded body of Example 20E, the thickness of the unremarkable general portion is 1.5 mm and the compression ratio is 706%; the thickness of the convex portion is 2.5 mm and the compression ratio is 209%; the thickness of the concave portion is 1.1 mm and the compression ratio is 2173%; the overall specific gravity is 1.40, the resin ratio is 62%, the flexural strength is 490 MPa, the flexural modulus is 42 GPa, the product appearance is "○", it has a good appearance, high strength and rigidity, and is lightweight.

[0764] Example 21E

[0765] like Figure 34 As shown, Example 21E is manufactured by depositing powdered thermosetting resin on both sides of a resin foam with a continuous bubble structure. Figure 32 Examples of fiber-reinforced molded articles.

[0766] Prepare four fiber substrates identical to those in Example 15E. On two stacked fiber substrates, apply 29g of resin A4 as a powdered thermosetting resin. On top of this, stack a resin foam with a continuous bubble structure identical to that in Example 15E, and then apply 29g of resin A4 as a powdered thermosetting resin on it in a substantially uniform manner. Then, place the remaining two fiber substrates on top of this to form a pre-molding laminate. Use SUS spacers with a thickness of 1.5mm. Otherwise, fabricate the fiber-reinforced molded body of Example 21E in the same manner as in Example 15E.

[0767] In the fiber-reinforced molded body of Example 21E, the thickness of the unremarkable general portion is 1.5 mm and the compression ratio is 706%; the thickness of the protruding portion is 2.5 mm and the compression ratio is 209%; the thickness of the concave portion is 1.1 mm and the compression ratio is 2173%; the overall specific gravity is 1.40, the resin ratio is 62%, the flexural strength is 490 MPa, the flexural modulus is 42 GPa, the product appearance is "○", it has a good appearance, high strength and rigidity, and is lightweight.

[0768] Example 22E

[0769] Example 22E is an example of a change in the type of resin foam with a continuous bubble structure as described in Example 15E.

[0770] As a resin foam with a continuous bubble structure, urethane resin foam (manufactured by INOAC CORPORATION, product name: MF-50, density 30kg / m³) with a thickness of 10mm and a planar size of 200×300mm was used. 3 In addition, the fiber-reinforced molded body of Example 22E was made in the same manner as Example 15E.

[0771] In the fiber-reinforced molded body of Example 22E, the thickness of the unremarkable general portion is 1.0 mm, and the compression ratio is 1329%; the thickness of the protruding portion is 2.0 mm, and the compression ratio is 413%; the thickness of the concave portion is 0.6 mm, and the compression ratio is 4900%; the overall specific gravity is 1.35, the resin ratio is 70%, the flexural strength is 460 MPa, the flexural modulus is 38 GPa, the product appearance is "○", it has a good appearance, high strength and rigidity, and is lightweight.

[0772] Example 23E

[0773] Except that the thickness of the resin foam with a continuous bubble structure is set to 30 mm, the fiber-reinforced molded body of Example 23E is made in the same manner as Example 1E.

[0774] The fiber-reinforced molded body of Example 23E has a compression ratio of 5257% and the appearance of the product is "△".

[0775] Example 24E

[0776] As a resin foam with a continuous bubble structure, urethane resin foam (manufactured by INOAC CORPORATION, product name: MF-50, density 30kg / m³) with a thickness of 1.5mm and a planar size of 200×300mm was used. 3 In addition, the fiber-reinforced molded body of Example 24E was made in the same manner as Example 1E.

[0777] The fiber-reinforced molded body of Example 24E has a compression rate of 168%, a specific gravity of 1.35, a resin ratio of 70%, a flexural strength of 300 MPa, a flexural modulus of 24 GPa, and an appearance of “○”.

[0778] Example 25E

[0779] Except for adjusting the amount of powdered thermosetting resin used to achieve a resin ratio of 45%, the fiber-reinforced molded body of Example 25E was made in the same manner as Example 1E.

[0780] The fiber-reinforced molded body of Example 25E has a compression rate of 2074%, a specific gravity of 1.33, a resin ratio of 45%, a flexural strength of 350 MPa, a flexural modulus of 28 GPa, and an appearance of "△".

[0781] Example 26E

[0782] Except for adjusting the amount of powdered thermosetting resin used to achieve a resin ratio of 85%, the fiber-reinforced molded body of Example 26E was made in the same manner as in Example 1E.

[0783] The fiber-reinforced molded body of Example 26E has a compression ratio of 1686%, a resin ratio of 85%, and an appearance of "△".

[0784] Comparative Example 1E

[0785] Comparative Examples 1E and 2E are comparative examples relative to Example 1E.

[0786] In Comparative Example 1E, except that resin F4 was used as a powdered thermosetting resin and the mold temperature was set to 100°C, the fiber-reinforced molded body of Comparative Example 1E was made in the same manner as in Example 1E.

[0787] Resin F4 is a phenolic resin manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50699, with an average particle size of 30μm.

[0788] Figure 37 The graph shows the viscosity measurement results of resin F4 (comparative examples 1E and 3E).

[0789] The compression ratio of the fiber-reinforced molded body in Comparative Example 1E was 1686%. However, due to the high minimum viscosity of the thermosetting resin (fast reaction), the thermosetting resin was difficult to impregnate the fiber matrix, so the fiber-reinforced molded body could not be obtained, and the physical property values ​​could not be measured.

[0790] Comparative Example 2E

[0791] As a powdered thermosetting resin, resin A4 and resin D4 were uniformly mixed in a weight ratio of 1:2, and the mold temperature was set to 160°C. Otherwise, the fiber-reinforced molded body of Comparative Example 2E was made in the same manner as in Example 1E.

[0792] Figure 37 The graph shows the viscosity measurement results for resin A4 / resin D4 = 1 / 2 (comparative examples 2E and 4E).

[0793] The compression ratio of the fiber-reinforced molded body in Comparative Example 2E was 1686%. However, due to the low maximum viscosity of the thermosetting resin in the temperature range of Tb to 190°C, the thermosetting resin could not be cured, and the fiber-reinforced molded body deformed during demolding. Therefore, it was impossible to measure the physical properties.

[0794] Comparative Example 3E

[0795] Comparative Examples 3E and 4E are comparative examples relative to Example 15E.

[0796] In Comparative Example 3E, except that resin F4 was used as a powdered thermosetting resin and the mold temperature was set to 100°C, the fiber-reinforced molded body of Comparative Example 3E was made in the same manner as in Example 15E.

[0797] The thermosetting resin of the fiber-reinforced molded body in Comparative Example 3E has a high minimum viscosity (fast reaction), making it difficult for the thermosetting resin to be impregnated into the fiber matrix and the resin foam with a continuous bubble structure. As a result, the fiber-reinforced molded body cannot be obtained, and the physical property values ​​cannot be measured.

[0798] Comparative Example 4E

[0799] As a powdered thermosetting resin, resin A4 and resin D4 were uniformly mixed in a weight ratio of 1:2, and the mold temperature was set to 160°C. Otherwise, the fiber-reinforced molded body of Comparative Example 4E was made in the same manner as in Example 15E.

[0800] In Comparative Example 4E, the fiber-reinforced molded body has a low maximum viscosity of the thermosetting resin in the temperature range of Tb to 190°C, so the thermosetting resin cannot be cured. Therefore, the fiber-reinforced molded body deforms during demolding, and its physical properties cannot be measured.

[0801] Thus, according to this design, fiber-reinforced molded articles can be obtained without the use of prepreg. Furthermore, according to this design, fiber-reinforced molded articles with an uneven or concave shape can also be obtained.

[0802] This form is not limited to the embodiments, and changes can be made without departing from the spirit.

[0803] Explanation of reference numerals in the attached figures

[0804] <Explanation of reference numerals in the illustrations of the first form>

[0805] 10: Fiber-reinforced resin molded articles,

[0806] 11, 11A~11F: Fiber substrate,

[0807] 15: Thermosetting resins,

[0808] 15A~15E: Powders of thermosetting resins.

[0809] 30: Mold,

[0810] 31: Lower mold,

[0811] 32: Upper mold,

[0812] <Explanation of reference numerals in the illustrations for the second form>

[0813] 110, 120, 130: Prepreg,

[0814] 111, 111A~111D: Fiber substrate,

[0815] 115: Thermosetting resins,

[0816] 115A~115C: Powders of thermosetting resins.

[0817] 141A, 141B: Plastic film for demolding.

[0818] 150: Mold

[0819] 151: Lower mold,

[0820] 152: Upper mold,

[0821] <Explanation of reference numerals in the illustrations for the third form>

[0822] 210: Fiber-reinforced resin molded article,

[0823] 211: Fiber substrate,

[0824] 215: Resin sheet,

[0825] 230: Mold,

[0826] 231: Lower mold,

[0827] 232: Upper mold,

[0828] <Explanation of the reference numerals in the illustrations for the fourth form>

[0829] 310: Fiber-reinforced sandwich composite.

[0830] 311, 311A~311D: Fiber-based substrates,

[0831] 315: core material,

[0832] 321: Thermosetting resin,

[0833] 321A, 321B: Powders of thermosetting resins.

[0834] 330: Mold,

[0835] 331: Lower mold,

[0836] 332: Upper mold,

[0837] <Explanation of the reference numerals in the illustrations for the fifth form>

[0838] 410, 420, 430, 440: Fiber-reinforced molded parts,

[0839] 411: core material,

[0840] 413: Resin foam with a continuous bubble structure.

[0841] 415: Fiber-reinforced materials

[0842] 417, 417A~417D: Fiber-based substrates.

[0843] 419, 419A, 419B: Powdered thermosetting resins.

[0844] 431, 441: concave part,

[0845] 433, 443: convex part,

[0846] 460, 470: Molds

[0847] 461, 471: Lower mold,

[0848] 462, 472: upper mold,

[0849] 473: Protrusions for forming concave portions,

[0850] 475: Groove for forming convex portion.

Claims

1. A fiber-reinforced resin molded article, formed by heating and compressing a fiber substrate together with a thermosetting resin to impregnate and cure the thermosetting resin in the fiber substrate, characterized in that... The cured thermosetting resin is formed by melting and solidifying a powder of the thermosetting resin disposed in contact with the fiber substrate during heating and compression. The fiber-reinforced resin molded body satisfies (4), (5), (7), and (8) below, and satisfies at least one of (1) to (3), and (6) below: (1) The bending strength measured according to JIS K7074 A method is above 450 MPa; (2) Thickness is less than 2mm; (3) The fiber substrate contains glass fiber, polyaramid fiber or basalt fiber; (4) The thermosetting resin contains a mixed resin of phenolic resin and epoxy resin, a mixed resin of phenolic resin and cyanate ester resin, a mixed resin of epoxy resin and cyanate ester resin, and a mixed resin of phenolic resin, epoxy resin and cyanate ester resin. (5) When the melting start temperature of the thermosetting resin is set to Ta℃ and the curing reaction start temperature is set to Tb℃, the value of (Tb-Ta) is 30≤(Tb-Ta)≤100; (6) The melting start temperature Ta of the thermosetting resin is 60~100℃; (7) The minimum viscosity of the thermosetting resin at a temperature above the melting start temperature Ta℃ is 2000 Pa. Below s; (8) The highest viscosity of the thermosetting resin within the range of curing reaction start temperature Tb℃~190℃ is 1000 Pa. s or more.

2. A vehicle, characterized in that, The fiber-reinforced resin molded article according to claim 1 is formed by heating and compressing a fiber substrate together with a thermosetting resin to impregnate and cure the thermosetting resin in the fiber substrate. The cured thermosetting resin is formed by melting and solidifying a powder of the thermosetting resin disposed in contact with the fiber substrate during heating and compression.

3. An organism, characterized in that, The fiber-reinforced resin molded article according to claim 1 is formed by heating and compressing a fiber substrate together with a thermosetting resin to impregnate and cure the thermosetting resin in the fiber substrate. The cured thermosetting resin is formed by melting and solidifying a powder of the thermosetting resin disposed in contact with the fiber substrate during heating and compression.

4. A method for manufacturing a fiber-reinforced resin molded article, used to manufacture the fiber-reinforced resin molded article of claim 1, comprising heating and compressing a fiber substrate and a thermosetting resin together, impregnating the fiber substrate with the thermosetting resin and curing it, characterized in that... The thermosetting resin powder is configured to contact the fiber substrate. The fiber substrate and the thermosetting resin powder are heated and compressed together using a mold, thereby melting the thermosetting resin powder and impregnating it within the fiber substrate, whereby it is then cured.

5. A method for manufacturing a fiber-reinforced resin molded article, used to manufacture the fiber-reinforced resin molded article of claim 1, comprising heating and compressing a fiber substrate and a thermosetting resin together, impregnating the fiber substrate with the thermosetting resin and curing it, characterized in that... The thermosetting resin powder is configured to contact the fiber substrate. The fiber substrate and the thermosetting resin powder are heated and compressed together using a mold, thereby melting the thermosetting resin powder, impregnating it within the fiber substrate, and then curing it. When the melting start temperature of the thermosetting resin is set to Ta℃ and the curing reaction start temperature is set to Tb℃, the temperature Tc℃ of the mold is [Tb+(Tb-Ta) / 3]-15≤Tc≤[Tb+(Tb-Ta) / 3]+20.

Images