Molded body and transport member

Abstract

To provide a molding which has high elastic modulus and suppresses occurrence of interlayer cracking caused by a volatile content derived from a resin.SOLUTION: A molding is composed of fiber-reinforced composite layers containing a reinforcement fiber and a resin, wherein the molding has two or more of the fiber-reinforced composite layers, and at least the one fiber-reinforced composite layer is a fiber-reinforced composite layer having a resin part which does not contain the reinforcement fiber in the whole thickness direction of the layer.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a molded body, a method for producing the same, and a transport member. [Background technology]

[0002] The robot hand of an industrial robot is attached to the end of the arm, and through the movement of the arm, it supports, grips, clamps, etc. the workpiece. Industrial robots are equipped with machining or welding devices to perform a variety of processes, but by attaching a robot hand to the end of the arm, it is particularly suitable for use in transporting substrates used in the manufacturing process of precision products such as liquid crystal displays (LCDs), plasma display panels (PDPs), and silicon wafers. In recent years, LCDs and PDPs have become larger, and as the size of the objects being transported increases, the robot hands also need to become larger.

[0003] Metals such as iron, stainless steel, and aluminum have traditionally been used as materials for robotic hands. However, as the size of the objects being transported increases and their weight increases, there is a demand for materials with a higher elastic modulus, i.e., materials that are less susceptible to deformation. Furthermore, as the size of robotic hands increases, the weight of the robotic hands themselves (dead weight) increases, and as this increases the deflection due to their own weight, there is a demand for lighter materials. However, with the aforementioned metal materials, there are limits to how high the elastic modulus and how light they can be. Therefore, the use of fiber-reinforced composite materials as materials for robot hands has been studied (Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4980712 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-292592 [Patent Document 3] Japanese Patent Application Laid-Open No. 2000-343476 Summary of the Invention [Problem to be solved by the invention]

[0005] Fiber-reinforced composite materials are manufactured by thermoforming a laminate of multiple prepregs containing reinforcing fibers and thermosetting resins. Because transported items such as semiconductor wafers and liquid crystal glass substrates are transported into a high-temperature (approximately 300°C) baking furnace, thermosetting resins are used as the resins for the fiber-reinforced composite materials that make up the robot hands because of their excellent heat resistance. However, when the laminate is thermoformed to manufacture a robot hand, volatile matter is generated during the thermoforming process, and if the volatile matter cannot be efficiently degassed, the volatile matter remains inside the fiber-reinforced composite material, which can cause interlayer cracks. The presence of interlayer cracks reduces the strength, elastic modulus, etc. of the fiber-reinforced composite material.

[0006] The present invention aims to provide a molded article having a high elastic modulus and suppressing the occurrence of interlayer cracks caused by volatile components derived from the resin, a method for producing the same, and a transport member including the molded article. [Means for solving the problem]

[0007] The present invention has the following aspects. [1] A molded body comprising a fiber-reinforced composite layer containing reinforcing fibers and a resin, The molded body has two or more of the fiber-reinforced composite layers, A molded article, wherein at least one of the fiber-reinforced composite layers is a fiber-reinforced composite layer having a resin portion that does not contain the reinforcing fibers throughout the thickness direction of the layer. [2] The molded article according to [1], wherein the resin portion is exposed on the outer peripheral surface. [3] The molded article according to [1] or [2], wherein the fiber-reinforced composite layer having the resin portion has a plurality of the resin portions. [4] The molded article according to any one of [1] to [3] above, wherein at least one of the fiber reinforced composite layers is a fiber reinforced composite layer that does not have the resin portion. [5] The molded body has three or more fiber-reinforced composite layers, The molded body according to [4], wherein one outermost layer and the other outermost layer in the thickness direction of the molded body are both fiber-reinforced composite layers that do not have the resin portion. [6] The molded article according to [4] or [5], wherein the total thickness of the fiber-reinforced composite layers not having the resin portion is 70% or more and 95% or less of the total thickness of the molded article. [7] The reinforcing fibers of the fiber-reinforced composite layer not having a resin portion are oriented in a first direction, the reinforcing fibers of the fiber-reinforced composite layer having the resin portion are oriented in a second direction, The molded article according to any one of [4] to [6] above, wherein the first direction and the second direction are different. [8] The molded body according to [7], which is a plate having a longitudinal direction. [9] The molded article according to [8], wherein the bending strength in the longitudinal direction is 150 MPa or more.

[10] The molded article according to [8] or [9], wherein the first direction is parallel to the longitudinal direction.

[11] The molded article according to

[10] , wherein the angle between the second direction and the longitudinal direction is 20 to 90°.

[12] The molded body of

[10] or

[11] , wherein in a cross section of the molded body cut in a direction parallel to the longitudinal direction, the ratio of the area of ​​the resin portion to the total area of ​​the fiber-reinforced composite layer having the resin portion is 2% or more.

[13] The molded body according to any one of

[10] to

[12] , wherein in a cross section of the molded body cut in a direction parallel to the longitudinal direction, the ratio of the area of ​​the resin portion to the total area of ​​the fiber-reinforced composite layer having the resin portion is 50% or less.

[14] The density of the resin is 1.0 g / cm 3 The molded article according to any one of [1] to

[13] above.

[15] The molded article according to any one of [1] to

[14] above, wherein the resin comprises a cured product of a thermosetting resin.

[16] The molded article according to

[15] , wherein the thermosetting resin comprises a phenolic resin.

[17] The molded article according to any one of the above [1] to

[16] , wherein the volume content of the reinforcing fibers is 40 to 70% by volume.

[18] The molded article according to any one of [1] to

[17] above, wherein the reinforcing fibers are carbon fibers.

[19] The molded body according to

[18] , wherein the carbon fiber is pitch-based.

[20] The molded article according to

[18] or

[19] , wherein the carbon fiber is a continuous fiber.

[21] A method for manufacturing a laminated structure comprising: laminating two or more prepregs containing reinforcing fibers and a resin; and heat-pressuring a laminate obtained by laminating the two or more prepregs; A method for producing a molded body, comprising, in the step of laminating two or more prepregs, arranging a second prepreg or a second laminate block formed by laminating two or more of the second prepregs on a surface of a first prepreg or a first laminate block formed by laminating two or more of the first prepregs so as to partially cover the surface of the first prepreg or the first laminate block in a top view.

[22] The method for producing a molded article according to

[21] , wherein in the step of laminating the two or more prepregs, two or more second prepregs or two or more second laminate blocks are arranged at intervals on the surface of the first prepreg or the first laminate block, thereby partially covering the surface of the first prepreg or the first laminate block.

[23] The first prepreg and the second prepreg are each a unidirectional prepreg, and the first laminate block is formed by stacking two or more of the first prepregs with the reinforcing fibers of the first prepregs aligned in the same direction, and the second laminate block is formed by stacking two or more of the second prepregs with the reinforcing fibers of the second prepregs aligned in the same direction, The method for producing a molded article according to

[21] or

[22] , wherein in the step of laminating the two or more prepregs, the orientation direction of the reinforcing fibers of the second prepreg or the second laminate block is set to a direction different from the orientation direction of the reinforcing fibers of the first prepreg or the first laminate block.

[24] A method for producing a molded body according to

[23] , wherein the first prepreg or the first laminate block is arranged so that the orientation direction of the reinforcing fibers in the first prepreg or the first laminate block is the longitudinal direction of the molded body, and the second prepreg or the second laminate block is laminated so that the orientation direction of the reinforcing fibers in the second prepreg or the second laminate block forms an angle of 20 to 90° with the longitudinal direction.

[25] The resin comprises a thermosetting resin; The method for producing a molded article according to any one of

[21] to

[24] above, wherein the content of the thermosetting resin in each of the first prepreg and the second prepreg is 15 to 45% by weight.

[26] The method for producing a molded article according to

[25] , wherein the thermosetting resin contains a phenolic resin.

[27] A transport member comprising the molded article according to any one of [1] to

[20] above. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a molded article having a high elastic modulus and suppressing the occurrence of interlayer cracks caused by volatile components derived from the resin, a method for producing the same, and a transport member including the molded article. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic top view showing an example of the molded body of the present embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view of the molded body shown in FIG. 1 in the longitudinal direction. [Figure 3] 2 is a schematic top view of a fiber-reinforced composite layer having a resin portion included in the molded article shown in FIG. 1. FIG. [Figure 4] FIG. 10 is a diagram illustrating an example of a lamination process. [Figure 5] FIG. 2 is a schematic cross-sectional view showing another example of a molded body. [Figure 6] FIG. 2 is a schematic cross-sectional view showing another example of a molded body. [Figure 7] FIG. 2 is a schematic cross-sectional view showing another example of a molded body. [Figure 8]FIG. 2 is a schematic cross-sectional view showing another example of a molded body. [Figure 9] FIG. 10 is a schematic top view showing another example of a fiber-reinforced composite layer having a resin portion. [Figure 10] FIG. 10 is a schematic top view showing another example of a fiber-reinforced composite layer having a resin portion. [Figure 11] FIG. 10 is a schematic top view showing another example of a fiber-reinforced composite layer having a resin portion. [Figure 12] FIG. 10 is a schematic top view showing another example of a fiber-reinforced composite layer having a resin portion. [Figure 13] FIG. 10 is a schematic top view showing another example of a fiber-reinforced composite layer having a resin portion. [Figure 14] FIG. 10 is a schematic top view showing another example of a fiber-reinforced composite layer having a resin portion. DETAILED DESCRIPTION OF THE INVENTION

[0010] In this specification, the volume content of reinforcing fibers is calculated by subtracting the weight loss caused by firing and carbonizing the molded body from the weight before firing and carbonization to obtain the carbon fiber weight, dividing the weight by the total volume and the specific gravity of the carbon fiber to obtain the percentage. The bending strength is measured by a method in accordance with JIS K 7074. The symbol "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits. The dimensional ratios in FIGS. 1 to 14 are different from the actual ones for the sake of convenience of explanation.

[0011] [Molded body] Fig. 1 is a schematic top view showing an example of a molded body of the present invention. Fig. 2 is a schematic cross-sectional view in the longitudinal direction of the molded body shown in Fig. 1. Fig. 3 is a schematic top view of a second fiber-reinforced composite layer provided in the molded body shown in Fig. 1. The molded article 1 in the example of Fig. 2 is a molded article made of fiber-reinforced composite layers, and has a total of five fiber-reinforced composite layers: four first fiber-reinforced composite layers 3 (fiber-reinforced composite layers that do not have a resin portion that does not contain reinforcing fibers throughout the entire thickness of the layer) and one second fiber-reinforced composite layer 5 (fiber-reinforced composite layer that has a resin portion that does not contain reinforcing fibers throughout the entire thickness of the layer). Hereinafter, the resin portion that does not contain reinforcing fibers throughout the entire thickness of the layer may be simply referred to as the resin portion. In the molded body 1, one second fiber-reinforced composite layer 5 is arranged between two first fiber-reinforced composite layers 3, and both the outermost layer on one side and the outermost layer on the other side in the thickness direction of the molded body 1 are first fiber-reinforced composite layers 3.

[0012] The molded body 1 is a plate having a longitudinal direction. That is, the ratio (L2 / L1) of the length L2 in the longitudinal direction (left-right direction, longitudinal direction in FIG. 1) to the length L1 in the width direction (up-down direction, short side direction in FIG. 1) exceeds 1. L2 / L1 should be greater than 1, but in the case of robot hand applications, from the viewpoint of reducing the weight of the robot hand, L2 / L1 is preferably 3 or greater, and more preferably 5 or greater. From the viewpoint of bending strength and robot hand stability, L2 / L1 is preferably 300 or less, and more preferably 100 or less. L1 may be, for example, 100 mm or more and less than 10,000 mm, and L2 may be, for example, more than 100 mm and 10,000 mm or less.

[0013] The bending strength in the longitudinal direction of the molded body 1 is preferably 150 MPa or more, more preferably 300 MPa or more, and even more preferably 450 MPa or more. There is no particular upper limit to this bending strength, but it can be, for example, 600 MPa or less. If the bending strength in the longitudinal direction is equal to or greater than the lower limit, the molded body 1 is less likely to deform even when a large substrate (for example, about 3 m in size) is placed on the molded body 1.

[0014] The volume content of the reinforcing fibers in the molded body 1 is preferably 40 to 70 volume %, more preferably 55 to 70 volume %, and even more preferably 60 to 65 volume %, relative to the volume of the molded body 1. If the volume content of the reinforcing fibers is within the above range, the strength of the molded body 1 will be superior.

[0015] <First fiber-reinforced composite layer> The first fiber-reinforced composite layer 3 is a fiber-reinforced composite layer that contains reinforcing fibers and a resin but does not have a resin portion. The first fiber-reinforced composite layer 3 is obtained, for example, by curing a prepreg that contains reinforcing fibers and a resin. The resin portion will be described in detail later. The first fiber-reinforced composite layer 3 may further contain other components in addition to the reinforcing fibers and resin, as needed, to the extent that the effects of the present invention are not significantly impaired.

[0016] 2, the reinforcing fibers of the first fiber-reinforced composite layer 3 are oriented in a first direction. The first direction is parallel to the longitudinal direction of the molded body 1. In other words, the angle between the first direction and the longitudinal direction is 0°. When the reinforcing fibers are oriented in the first direction, and the first direction is parallel to the longitudinal direction, the molded body 1 has better bending strength in the longitudinal direction.

[0017] Examples of reinforcing fibers include inorganic fibers, organic fibers, metal fibers, and hybrid reinforcing fibers that combine these. Examples of inorganic fibers include carbon fibers, graphite fibers, silicon carbide fibers, alumina fibers, tungsten carbide fibers, boron fibers, and glass fibers. Examples of organic fibers include aramid fibers, high-density polyethylene fibers, and other common nylon fibers and polyester fibers. Examples of metal fibers include stainless steel, iron, and other fibers. Examples of hybrid reinforcing fibers include metal-coated carbon fibers. The reinforcing fibers may be used alone or in combination of two or more.

[0018] The reinforcing fiber is preferably carbon fiber in terms of specific strength and specific rigidity. The carbon fiber is not particularly limited, but examples thereof include polyacrylonitrile (PAN)-based carbon fiber, pitch-based carbon fiber made from petroleum or coal pitch, rayon-based carbon fiber, and lignin-based carbon fiber. Among these, pitch-based carbon fiber is preferred from the viewpoint of specific rigidity. Pitch-based carbon fiber is a carbon fiber made from petroleum or coal pitch. The carbon fibers are preferably continuous fibers in terms of the bending strength of the molded article.

[0019] The carbon fiber is typically used in the form of a carbon fiber bundle in which a plurality of carbon fibers are bundled together. The number of filaments in the carbon fiber bundle is preferably 1000 to 60000, more preferably 1000 to 50000, and even more preferably 12000 to 48000. When the number of filaments in the carbon fiber bundle is within the above range, productivity and mechanical properties on an industrial scale are excellent.

[0020] The volume content of the reinforcing fibers in the first fiber-reinforced composite layer 3 is preferably 40 to 70% by volume, more preferably 48 to 68% by volume, and more preferably 60 to 65% by volume, relative to the volume of the first fiber-reinforced composite layer 3.

[0021] Examples of the resin include a cured product of a thermosetting resin and a thermoplastic resin. Examples of thermosetting resins include epoxy resins, phenolic resins, unsaturated polyester resins, vinyl ester resins, phenoxy resins, alkyd resins, urethane resins, urea resins, melamine resins, maleimide resins, and cyanate resins. Examples of thermoplastic resins include polyamides (nylon 6, nylon 66, etc.), polyolefins (polyethylene, polypropylene, etc.), modified polyolefins, polyesters (polyethylene terephthalate, polybutylene terephthalate, etc.), polycarbonate, polyamideimide, polyphenylene oxide, polysulfone, polyethersulfone, polyetheretherketone, polyetherimide, polystyrene, ABS, polyphenylene sulfide, liquid crystal polyester, and copolymers of acrylonitrile and styrene. These resins may be used alone or in combination of two or more.

[0022] The resin preferably contains a cured product of a thermosetting resin, in order to provide a molded article with excellent heat resistance. Among thermosetting resins, phenolic resins are preferred. Phenolic resins have excellent heat resistance when cured, and by using phenolic resins, molded articles can be used in applications requiring heat resistance, such as transport components for transporting goods through high-temperature (approximately 300°C) baking furnaces used in the manufacture of LCDs and PDPs. Furthermore, since the curing reaction of phenolic resins is a condensation reaction, a large amount of volatile matter is generated during curing. Therefore, interlayer cracks are likely to occur with conventional techniques, making the present invention highly useful. Examples of the phenolic resin include resol-type phenolic resin, novolac-type phenolic resin, etc. As the resol-type phenolic resin, a water-soluble phenolic resin is preferred.

[0023] The density of the resin is set to 1.0 g / cm3 from the viewpoint of handling of the molded product. 3 More than 1.2 g / cm is preferable. 3 The upper limit of the density of the resin is not particularly limited, but is, for example, 1.23 g / cm 3 The resin density is the value at 25°C.

[0024] Other components that can be used include known additives, such as curing agents, release agents, defoamers, flame retardants, weather resistance improvers, antioxidants, heat stabilizers, UV absorbers, plasticizers, lubricants, colorants, compatibilizers, fillers, and conductive fillers. One type of additive may be used alone, or two or more types may be used in combination.

[0025] The thickness of each first fiber-reinforced composite layer 3 is preferably 0.1 to 0.5 mm, and more preferably 0.2 to 0.4 mm. If the thickness of the first fiber-reinforced composite layer 3 is equal to or greater than the lower limit, workability during lamination is improved, and if the thickness is equal to or less than the upper limit, uniformity of the resin and reinforcing fibers within the molded product is improved.

[0026] The total thickness of the first fiber-reinforced composite layers 3 in the molded body 1 is preferably 70% to 95% of the entire thickness of the molded body 1, more preferably 75% to 90% and even more preferably 80% to 85%. If the total thickness of the first fiber-reinforced composite layers 3 is equal to or greater than the lower limit, the rigidity of the molded body 1 will be superior, and if it is equal to or less than the upper limit, the effect of suppressing the occurrence of interlayer cracks will be superior.

[0027] <Second fiber-reinforced composite layer> The second fiber-reinforced composite layer 5 is a fiber-reinforced composite layer that contains reinforcing fibers and a resin and has a resin portion. The second fiber-reinforced composite layer 5 is obtained, for example, by curing a prepreg that contains reinforcing fibers and a resin. The second fiber-reinforced composite layer 5 may further contain other components in addition to the reinforcing fibers and resin, as needed, to the extent that the effects of the present invention are not significantly impaired.

[0028] The reinforcing fibers, resin, and other components are the same as those described above. The volume content of the reinforcing fibers in the second fiber-reinforced composite layer 5 is preferably 40 to 70% by volume, and more preferably 60 to 65% by volume, relative to the volume of the second fiber-reinforced composite layer 5.

[0029] 2, the reinforcing fibers of the second fiber-reinforced composite layer 5 are oriented in a second direction, which is different from the first direction. Volatile matter derived from the resin tends to move along the orientation direction of the reinforcing fibers. When the second direction is different from the first direction parallel to the longitudinal direction of the molded body 1, the distance traveled by the volatile matter to reach the outer surface of the molded body is shorter than when the second direction is the same as the first direction, and the volatile matter is more easily discharged. The angle between the second direction and the longitudinal direction is preferably 20 to 90°, more preferably 45 to 90°, and particularly preferably 90°.

[0030] The second fiber-reinforced composite layer 5 has a plurality of resin portions 51 as shown in FIGS. The resin portion 51 is a region that contains resin and does not contain reinforcing fibers across the entire thickness of the second fiber reinforced composite layer 5. The region of the second fiber reinforced composite layer 5 other than the resin portion 51 contains reinforcing fibers and resin.

[0031] 2, resin portion 51 is provided linearly from one end to the other in the short-side direction of molded body 1, i.e., along a direction perpendicular to the long-side direction, in a top view. Resin portion 51 is exposed on the outer peripheral surface of molded body 1.

[0032] In a cross section cut parallel to the longitudinal direction of the molded body 1, the ratio of the area of ​​the resin portion 51 to the total area of ​​the second fiber-reinforced composite layer 5 is preferably 2% or more, more preferably 4% or more, even more preferably 5% or more, and preferably 50% or less, more preferably 25% or less, and even more preferably 10% or less. When there are multiple resin portions 51, the area of ​​the resin portions 51 is the total area of ​​the multiple resin portions 51. If the area ratio of the resin portions 51 is equal to or greater than the lower limit, the effect of suppressing the occurrence of interlayer cracks is more excellent. If the area ratio of the resin portions 51 is equal to or less than the upper limit, the bending strength of the molded body 1 in the longitudinal direction is more excellent. The cross section cut in a direction parallel to the longitudinal direction may be the side surface. If the shape of the resin part 51 is not constant depending on the cross section, the average area may be the area measured from three or more cross sections including the central cross section and both side surfaces in the short direction.

[0033] When viewed from above, the ratio of the area of ​​the resin portion 51 to the total area of ​​the second fiber-reinforced composite layer 5 is preferably 2% or more, more preferably 4% or more, even more preferably 5% or more, and preferably 50% or less, more preferably 25% or less, and even more preferably 10% or less. When there are multiple resin portions 51, the area of ​​the resin portions 51 is the total area of ​​the multiple resin portions 51. If the ratio of the area of ​​the resin portions 51 is equal to or greater than the lower limit, the effect of suppressing the occurrence of interlayer cracks is more excellent. If the ratio of the area of ​​the resin portions 51 is equal to or less than the upper limit, the longitudinal bending strength of the molded body 1 is more excellent.

[0034] In a cross section taken parallel to the longitudinal direction of molded body 1, the width W of each of the plurality of resin portions 51 is preferably 3 mm or more, more preferably 5 mm or more, and even more preferably 10 mm or more, and is preferably 100 mm or less, more preferably 50 mm or less, and even more preferably 30 mm or less. If the width W of resin portion 51 is equal to or greater than the lower limit, the effect of suppressing the occurrence of interlayer cracks is better, and if it is equal to or less than the upper limit, the bending strength of molded body 1 in the longitudinal direction is better. When the width of the resin portion 51 is not constant in the thickness direction, the maximum width is defined as the width W of the resin portion 51.

[0035] In a cross section cut parallel to the longitudinal direction of the molded body 1, the distance L3 between adjacent resin portions 51 in the second fiber-reinforced composite layer 5 is preferably 50 mm or more, more preferably 100 mm or more, and even more preferably 200 mm or more, and is preferably 1000 mm or less, more preferably 500 mm or less, and even more preferably 300 mm or less. If the distance L3 is equal to or greater than the lower limit, the bending strength in the longitudinal direction of the molded body 1 is superior, and if it is equal to or less than the upper limit, the effect of suppressing the occurrence of interlayer cracks is superior.

[0036] In a cross section cut parallel to the longitudinal direction of molded body 1, the distance L4 from the resin portion 51 closest to the longitudinal outer edge of second fiber-reinforced composite layer 5 (the outer peripheral surface of molded body 1) to said outer edge is preferably 50 mm or more, more preferably 100 mm or more, even more preferably 200 mm or more, and preferably 1000 mm or less, more preferably 500 mm or less, and even more preferably 300 mm or less. If distance L4 is equal to or greater than the lower limit, the longitudinal bending strength of molded body 1 is superior, and if it is equal to or less than the upper limit, the effect of suppressing the occurrence of interlayer cracks is superior.

[0037] Where the width W of the resin portion, the length L2 in the longitudinal direction, the distance L3 between adjacent resin portions, and the distance L4 to the outer edge are the above-mentioned resin portions, the ratio W / L2 is preferably 0.0005 or more, more preferably 0.002 or more, and even more preferably 0.005 or more, and is preferably 0.33 or less, more preferably 0.17 or less, and even more preferably 0.1 or less. If the ratio W / L2 is equal to or greater than the lower limit, the molded body 1 exhibits excellent interlayer crack suppression effects, and if it is equal to or less than the upper limit, the molded body 1 exhibits excellent bending strength. The ratios W / L3 and W / L4 are preferably equal to or greater than 0.003, more preferably 0.01 or more, and even more preferably 0.03 or more, and are preferably equal to or less than 2.0, more preferably 0.5 or less, and even more preferably 0.15 or less. If the ratios W / L3 and W / L4 are equal to or greater than the lower limit, the molded body 1 exhibits excellent interlayer crack suppression effects, and if it is equal to or less than the upper limit, the molded body 1 exhibits excellent bending strength. The ratio L3 / L2 or the ratio L4 / L2 can be set to, for example, 0.05 to 0.9.

[0038] The thickness per layer of the second fiber-reinforced composite layer 5 is preferably 0.1 to 0.5 mm, and more preferably 0.2 to 0.4 mm. If the thickness of the second fiber-reinforced composite layer 5 is equal to or greater than the above-mentioned lower limit, workability during lamination is improved, and if the thickness is equal to or less than the above-mentioned upper limit, uniformity of the resin and reinforcing fibers within the molded product is improved.

[0039] The thickness of the second fiber-reinforced composite layer 5 in the molded body 1 (total thickness if there are multiple layers) is preferably 5% to 30% of the overall thickness of the molded body 1, more preferably 10% to 25%, and even more preferably 15% to 20%.

[0040] The applications of the molded body 1 are not particularly limited, but examples thereof include transport members, structural members for aircraft, structural members for automobiles, and precision equipment housings. The molded article 1 has a high elastic modulus and excellent bending strength in the longitudinal direction, and is therefore suitable for use as a transport member such as a robot hand for an industrial robot. A transport member including the molded body 1 is less likely to deform when transporting an object, even if the object is large. Furthermore, since the molded body 1 is lighter than a metal material, it is less likely to bend under its own weight.

[0041] <Method of manufacturing molded body> The molded body 1 can be produced, for example, by a manufacturing method including a step of laminating two or more prepregs containing reinforcing fibers and resin (lamination step), and a step of heat-pressure-molding the laminate of the two or more prepregs (molding step).

[0042] (prepreg) Prepregs contain reinforcing fibers and resin. The reinforcing fibers are impregnated with the resin. Examples of prepregs include unidirectional prepregs, cross prepregs, and sheet molding compounds (SMC). The prepreg may further contain other components in addition to the reinforcing fibers and resin, as needed, within the scope of not significantly impairing the effects of the present invention. The prepreg to be used may be one that does not have a resin portion that does not contain reinforcing fibers throughout the thickness direction.

[0043] The reinforcing fibers are the same as those described above. The content of reinforcing fibers in the prepreg is preferably 55 to 85 wt %, more preferably 65 to 75 wt %, based on the weight of the prepreg. If the content of reinforcing fibers is within this range, the strength of the obtained molded article will be superior.

[0044] Examples of the resin include the above-mentioned thermosetting resins and thermoplastic resins, with thermosetting resins being preferred and phenolic resins being particularly preferred. The resin content in the prepreg is preferably 15 to 45 wt %, more preferably 25 to 35 wt %, based on the weight of the prepreg. If the resin content is within this range, the strength of the obtained molded article will be superior.

[0045] The other components are the same as above. The content of other components in the prepreg is preferably 0 to 3% by weight, more preferably 0 to 1% by weight, based on the weight of the prepreg.

[0046] The thickness of the prepreg is preferably 0.05 to 1.0 mm, more preferably 0.15 to 0.4 mm.

[0047] The prepregs used include at least a first prepreg 13 and a second prepreg 15. The materials and compounding ratios constituting the first prepreg 13 and the second prepreg 15 may be the same or different. The first prepreg 13 forms the first fiber reinforced composite layer 3, and the second prepreg 15 forms the second fiber reinforced composite layer 5. The fiber reinforced composite layer can be formed by curing the prepregs under heat and pressure.

[0048] In this example, the first prepreg 13 is a unidirectional prepreg in which the reinforcing fibers are oriented in a first direction. The first prepreg 13 is in the form of a sheet with a ratio of its longitudinal length to its widthwise length exceeding 1. The ratio of the longitudinal length to its widthwise length of the first prepreg 13 is equal to the ratio (L2 / L1) of the longitudinal length L2 to the widthwise length L1 of the molded body 1.

[0049] The second prepreg 15 is similar to the first prepreg 13 except that it is a unidirectional prepreg in which the reinforcing fibers are oriented in a second direction, and is smaller in size than the first prepreg 13 . In this example, the second prepreg 15 has the same length in the short side direction as the first prepreg 13, but is shorter in the long side direction than the first prepreg 13. Specifically, the length in the long side direction is set to a length such that when two or more second prepregs are arranged on the first prepreg 13 at intervals along the long side, they all fit on the first prepreg 13. The short side direction and long side direction here both refer to the short side direction and long side direction of the first prepreg 13.

[0050] The prepreg may be commercially available or may be manufactured by a known manufacturing method. Examples of the manufacturing method of the prepreg include a method in which a resin or a mixture of a resin and other components is coated on a release paper or a film, and then a plurality of reinforcing fibers aligned in one direction are overlapped and impregnated with the coating, and the coating is left to cure for a certain period of time.

[0051] (Lamination process) In the lamination process, first, as shown in Fig. 4, two or more second prepregs 15 are placed at intervals on a first laminate block in which two first prepregs 13 are laminated. At this time, when viewed from above, the surface of the first laminate block is partially covered with two or more second prepregs 15. Next, two more first prepregs 13 are laminated on these second prepregs 15. Thereafter, vacuum degassing is performed as necessary.

[0052] In the laminate obtained as described above, a slit portion S is formed between adjacent second prepregs. The slit portion S is formed linearly from one end to the other end in the short-side direction of the first laminate block in a top view. When the obtained laminate is molded under heat and pressure in a molding step, resin flows into the slit portion S from the second prepreg and the first prepreg around the slit portion S, forming a resin portion 51, and a molded body 1 is obtained.

[0053] (molding process) As the hot pressure molding method, general methods such as press molding, autoclave molding, etc. can be used. Among these, press molding is preferred from the viewpoint of productivity. In the hot and pressure molding, the heating conditions can be 150 to 200° C. The pressure conditions can be 0.3 to 1.0 MPa. The heating and pressure time can be 240 to 720 minutes.

[0054] <Action and effect> The molded body 1 is made up of fiber-reinforced composite layers (first fiber-reinforced composite layer 3 and second fiber-reinforced composite layer 5), making it lighter than metal materials. The inclusion of the first fiber-reinforced composite layer 3, which does not contain a resin portion, allows for a high elastic modulus. The inclusion of the second fiber-reinforced composite layer 5, which contains a resin portion 51, makes it possible to suppress the occurrence of interlayer cracks caused by volatile components derived from the resin. The reinforcing fibers in the fiber-reinforced composite layer are densely packed. Conventionally, when volatile matter from the resin is generated during the production of a molded product, the reinforcing fibers prevent the volatile matter from moving or being discharged, causing the volatile matter to remain between the layers and causing interlayer cracks and voids. In contrast, the resin portion 51 in this embodiment does not contain reinforcing fibers throughout the thickness direction, and therefore is more permeable to volatile components derived from the resin than a portion containing reinforcing fibers. The volatile components are discharged from the molded body 1 through the resin portion 51, thereby suppressing the occurrence of interlayer cracks. Volatile matter generated in the second fiber-reinforced composite layer 5 moves along the second direction and is discharged from the molded body 1. Volatile matter generated in the first fiber-reinforced composite layer 3 moves along the first direction, and along the way moves to the resin portion 51 of the adjacent second fiber-reinforced composite layer 5, and then moves along the second direction and is discharged from the molded body 1. By causing the volatile matter in the first fiber-reinforced composite layer 3 to also move along the second direction, when the length of the molded body 1 in the second direction is shorter than the length of the molded body 1 in the first direction, the distance that the volatile matter travels to reach the outer peripheral surface of the molded body is shortened, and the volatile matter discharge effect is improved. Furthermore, the resin portion 51 is exposed on the outer peripheral surface of the molded body 1, which improves the effect of discharging volatile matter.

[0055] <Other embodiments> The molded article of this embodiment is not limited to the above. For example, the molded body may not have the first fiber-reinforced composite layer. The number of fiber reinforced composite layers in the molded body may be two or more. The molded article may have a structure in which both one outermost layer and the other outermost layer in the thickness direction of the molded article are the first fiber-reinforced composite layers, and the upper limit of the number of fiber-reinforced composite layers can be set appropriately depending on the thickness of the molded article, and is, for example, 50 layers.

[0056] Either one or both of the outermost layer on one side and the outermost layer on the other side in the thickness direction of the molded body may be the second fiber-reinforced composite layer. The presence of the second fiber-reinforced composite layer in a layer other than the outermost layer tends to more easily suppress the occurrence of interlaminar cracks and also results in an excellent appearance of the molded article. Therefore, it is preferable that both one outermost layer and the other outermost layer in the thickness direction of the molded article are the first fiber-reinforced composite layer.

[0057] An example of the layer structure of the molded body is shown in FIGS. The molded article in FIG. 5 has a three-layer structure in which one first fiber reinforced composite layer is laminated on each side of one second fiber reinforced composite layer. The molded article in FIG. 6 has a six-layer structure in which one second fiber-reinforced composite layer is laminated on each side of four first fiber-reinforced composite layers. The molded article in FIG. 7 has a two-layer structure in which one first fiber-reinforced composite layer and one second fiber-reinforced composite layer are laminated.

[0058] The number of resin parts in the second fiber reinforced composite layer may be one. In terms of being excellent in the effect of suppressing the occurrence of interlaminar cracks, it is preferable that the second fiber reinforced composite layer has a plurality of resin portions. When the second fiber-reinforced composite layer has a plurality of resin portions, the shapes of the plurality of resin portions may be the same or different.

[0059] In the example shown, the cross section of the resin portion cut in a direction parallel to the longitudinal direction of the molded body has a rectangular cross section, but the cross section of the resin portion is not limited to this. For example, as shown in FIG. 8, the cross-sectional shape of the resin portion may be an ellipse, a shape inclined relative to the thickness direction, a triangle, or the like.

[0060] An example has been shown in which the resin part is arranged in a straight line from one end to the other end of the short side of the molded body when viewed from above, and the resin part is exposed on the outer peripheral surface of the molded body, but the shape of the resin part when viewed from above is not limited to this. For example, as shown in FIG. 9, the width of the resin portion in the longitudinal direction may be increased. As shown in FIG. 10, the resin portion does not have to be exposed on the outer peripheral surface of the molded body. As shown in FIGS. 11 and 12, at least a part of the outer edge of the resin portion may be curved. As shown in FIG. 13, the resin portion may be provided along the longitudinal direction of the molded body. As shown in FIG. 14, the resin portion may be provided along a direction other than the longitudinal and lateral directions of the molded body. In terms of ease of discharging volatile matter, it is preferable that the resin portion be exposed on the outer peripheral surface of the molded body and / or be arranged along the short direction of the molded body, and it is more preferable that it be both.

[0061] Although an example has been shown in which the reinforcing fibers of the first fiber-reinforced composite layer are oriented in a first direction and the reinforcing fibers of the second fiber-reinforced composite layer are oriented in a second direction, and the second direction is different from the first direction, the second direction may also be parallel to the first direction. The orientation direction of the reinforcing fibers in the first fiber-reinforced composite layer and the orientation direction of the reinforcing fibers in the second fiber-reinforced composite layer do not have to be unidirectional. Examples of reinforcing fibers that are not oriented in one direction include those in which the reinforcing fibers are continuous fibers and are woven in a fabric form (plain weave, twill weave, satin weave, etc.), and those in which the reinforcing fibers are short fibers and are oriented in random directions.

[0062] Although the example in which the molded body is a plate having a longitudinal direction is shown, the shape of the molded body is not limited to the illustrated example and can be appropriately changed depending on the application. For example, the molded body may have a square plate shape, a curved plate shape, or the like.

[0063] In the lamination process, an example has been shown in which two or more second prepregs are placed at intervals on top of the first laminate block to partially cover the surface of the first laminate block, but the method of partially covering the surface of the first laminate block is not limited to this. For example, a second prepreg may be prepared by cutting a portion of a prepreg of the same size as the first laminate block, and this second prepreg may be placed on the first laminate block. After laminating the second prepreg, a portion of the second prepreg may be cut out to form a slit portion.

[0064] In the lamination step, if necessary, after arranging two or more second prepregs and before laminating the first laminate block, resin may be placed in the slit portion S. By placing resin, even if the size of the slit portion S is large, the resin can be distributed throughout the entire slit portion S.

[0065] The number and stacking order of the first prepregs and second prepregs to be stacked in the stacking step can be set appropriately depending on the number and stacking order of the first fiber-reinforced composite layers and second fiber-reinforced composite layers in the molded body to be produced. For example, a first prepreg may be used instead of the first laminate block, a second laminate block in which two or more second prepregs are laminated may be used instead of the second prepreg, or the first laminate block does not have to be laminated on the second prepreg. [Example]

[0066] The present invention will be explained in more detail below by showing examples, but the present invention is not limited to these examples in any way.

[0067] Example 1 Carbon fiber weight (FAW) 400g / m 2 A unidirectional prepreg containing 32% by weight of phenolic resin was prepared. The unidirectional prepreg was cut into four first prepreg pieces measuring 1400 mm x 275 mm so that the longitudinal direction coincided with the direction in which the carbon fibers were aligned. Next, two of the four first prepregs were stacked with their orientations aligned in the first direction to obtain a first laminated block. Next, the unidirectional prepreg was cut into pieces measuring 275 mm x 275 mm to obtain five pieces of second prepreg. Five sheets of the second prepreg were placed on top of the first laminate block along its longitudinal direction, spaced 5 mm apart, with the carbon fiber alignment direction (second direction) perpendicular to the first direction. Two sheets of the first prepreg, each measuring 1400 mm x 275 mm, were then stacked on top of the first prepreg, oriented in the first direction. This process was repeated seven times, resulting in seven stacks of two-layer first laminate blocks, each consisting of a combination of one second prepreg layer made of five second prepregs and two first laminate blocks, resulting in a prepreg laminate of 35 layers in total. The resulting laminate was then heated in an autoclave at 177°C and 6 kg / cm. 2 The phenolic resin was cured by applying a pressure of 1400 mm (L2) x 275 mm (L1) and maintaining the pressure for 120 minutes to obtain a molded body having dimensions of 1400 mm (L2) x 275 mm (L1). The resulting molded articles were evaluated as follows. The evaluation results are shown in Table 1.

[0068] (Volume content of reinforcing fibers) The weight of the carbon fiber obtained by subtracting the weight loss caused by firing and carbonizing the molded body from the weight before firing and carbonization was divided by the total volume and the specific gravity of the carbon fiber to calculate the percentage.

[0069] (Ratio of the area of ​​the resin portion to the total area of ​​the second fiber-reinforced composite layer in the longitudinal cross section) In a cross section of the molded article having dimensions of 1400 × 275 mm cut in a direction parallel to the longitudinal direction, the thickness and length of the second fiber-reinforced composite layer were measured using a tape measure and calipers, and the area of ​​the entire second fiber-reinforced composite layer was calculated. Similarly, the total area of ​​the resin portion was calculated and divided by the area of ​​the entire second fiber-reinforced composite layer to calculate the ratio of the area of ​​the resin portion to the total area of ​​the second fiber-reinforced composite layer.

[0070] (bending strength) The bending strength in the longitudinal direction of the molded article having dimensions of 1400 mm×275 mm was measured in accordance with JIS K 7074.

[0071] (Evaluation of interlayer cracks) Eleven measurement points were set on the molded body measuring 1400 mm x 275 mm. Specifically, one measurement point was set at a corner, four measurement points were set at 467 mm intervals along the length from that measurement point, three measurement points were set at 350 mm intervals evenly spaced along the length in the center, and four measurement points were set at the other corner in the same manner as above, for a total of 11 measurement points. At the measurement points, the thickness was measured using a micrometer, and the average value of the 11 points was taken as T (mm). At the measurement points, an ultrasonic wave propagation device was used to measure the ultrasonic wave propagation time in the thickness direction of the molded article, and the average value of 11 points was taken as S (μs). A molded body without cracks has a small value of (ultrasonic wave propagation time S) / (thickness T)=C. For the molded body of Example 1, the above T (mm) and S (μs) were measured, and (ultrasonic propagation time S) / (thickness T)=C was calculated, resulting in C=0.53.

[0072] <Comparative Example 1> A molded article was produced and evaluated in the same manner as in Example 1, except that five sheets of the second prepreg were arranged on the first laminate block along the longitudinal direction thereof without leaving any gaps of 5 mm between them, so that the paralleling direction of the carbon fibers (second direction) was perpendicular to the first direction. The evaluation results are shown in Table 1.

[0073] [Table 1] [Explanation of symbols]

[0074] 1...molded body, 3...first fiber reinforced composite layer (fiber reinforced composite layer without resin portion), 5...second fiber reinforced composite layer (fiber reinforced composite layer with resin portion), 13...first prepreg, 15...second prepreg, 51...resin portion

Claims

1. A molded body comprising a fiber-reinforced composite layer containing reinforcing fibers and a resin, The molded body has two or more of the fiber-reinforced composite layers, At least one of the fiber-reinforced composite layers has a resin portion that does not contain the reinforcing fibers throughout the thickness direction of the layer, A molded article, wherein at least one of the fiber-reinforced composite layers is a fiber-reinforced composite layer that does not have the resin portion.

2. The molded article according to claim 1 , wherein the resin portion is exposed on an outer peripheral surface.

3. The molded article according to claim 1 or 2, wherein the fiber-reinforced composite layer having the resin portion has a plurality of the resin portions.

4. The molded body has three or more fiber-reinforced composite layers, The molded body according to any one of claims 1 to 3, wherein one outermost layer and the other outermost layer in the thickness direction of the molded body are both fiber-reinforced composite layers that do not have the resin portion.

5. The molded body according to any one of claims 1 to 4, wherein the total thickness of the fiber reinforced composite layer not having the resin portion is 70% or more and 95% or less of the total thickness of the molded body.

6. the reinforcing fibers of the fiber-reinforced composite layer not having the resin portion are oriented in a first direction, the reinforcing fibers of the fiber-reinforced composite layer having the resin portion are oriented in a second direction, The molded body according to any one of claims 1 to 5, wherein the first direction and the second direction are different.

7. The molded article according to claim 6, which is a plate having a longitudinal direction.

8. The molded article according to claim 7 , wherein the bending strength in the longitudinal direction is 150 MPa or more.

9. The molded article according to claim 7 or 8, wherein the first direction is parallel to the longitudinal direction.

10. The molded body according to claim 9, wherein the angle between the second direction and the longitudinal direction is 20 to 90 degrees.

11. 11. The molded body according to claim 9 or 10, wherein in a cross section of the molded body cut in a direction parallel to the longitudinal direction, the ratio of the area of ​​the resin portion to the total area of ​​the fiber-reinforced composite layer having the resin portion is 2% or more.

12. In a cross section of the molded body cut in a direction parallel to the longitudinal direction, the ratio of the area of ​​the resin portion to the total area of ​​the fiber reinforced composite layer having the resin portion is 50% or less. The molded body according to any one of claims 9 to 11.

13. The density of the resin is 1.0 g / cm ３ The molded article according to any one of claims 1 to 12.

14. The molded body according to any one of claims 1 to 13, wherein the resin comprises a cured product of a thermosetting resin.

15. The molded article according to claim 14 , wherein the thermosetting resin comprises a phenolic resin.

16. The molded body according to any one of claims 1 to 15, wherein the volume content of the reinforcing fibers is 40 to 70% by volume.

17. The molded body according to any one of claims 1 to 16, wherein the reinforcing fibers are carbon fibers.

18. 18. The molded body according to claim 17, wherein the carbon fibers are pitch-based.

19. The molded article according to claim 17 or 18, wherein the carbon fibers are continuous fibers.

20. A transport member comprising the molded article according to any one of claims 1 to 19.

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