Intermediate material, manufacturing method of intermediate material, and manufacturing method of molded body

Abstract

To provide an intermediate material capable of obtaining a molding excellent in mechanical physical properties such as bending strength, a method for manufacturing an intermediate material, and a method for manufacturing a molding.SOLUTION: There is provided an intermediate material 1 in which carbon fiber base materials (A) 12 that contains a carbon fiber and has a fiber weight basis of 200-600 g / m2 are layered on and integrated with both surfaces of a thermoplastic resin base material (B) 10 containing a thermoplastic resin, and surface roughness Sa on the surface opposite to the thermoplastic resin base material (B) 10 of the carbon fiber base material (A) 12 is 1,500-70,000 nm. A method for manufacturing a molding includes pressing the intermediate material 1 to obtain a molding.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an intermediate material, a method for manufacturing the intermediate material, and a method for manufacturing a molded body. [Background technology]

[0002] Fiber-reinforced resin composite materials containing reinforcing fibers are lightweight and high-strength, and are therefore widely used in various fields such as transportation equipment for automobiles, railways, and aircraft, electronic devices, furniture, building materials, etc. A known fiber-reinforced resin composite material is a molded product obtained by laminating a glass fiber-reinforced resin substrate containing glass fibers and a thermoplastic resin and a carbon fiber substrate containing carbon fibers and a thermoplastic resin fiber, and press-molding the laminate using a pair of hot plates.

[0003] One method for producing a molded body is a heat-and-cool molding method in which a laminate of a glass fiber reinforced resin substrate and a carbon fiber substrate is heated to a temperature above the melting point of the thermoplastic resin, press-molded with a hot plate at a high temperature above the melting point, and then cooled and solidified while being pressed with a hot plate at a low temperature below the melting point (Patent Documents 1 and 2).Another known method is an isothermal molding method in which a laminate of a glass fiber reinforced resin substrate and a carbon fiber substrate is heated to a temperature above the melting point of the thermoplastic resin in an oven or the like, and then press-molded with a hot plate at a low temperature below the melting point (Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-28510 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-208791 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-286817 Summary of the Invention [Problem to be solved by the invention]

[0005] However, molded bodies obtained by the molding methods described in Patent Documents 1 to 3 may not have sufficient mechanical properties such as bending strength after secondary molding.

[0006] An object of the present invention is to provide an intermediate material from which a molded article having excellent mechanical properties such as bending strength can be obtained, a method for manufacturing the intermediate material, and a method for manufacturing the molded article. [Means for solving the problem]

[0007] The present invention has the following configuration. [1] A thermoplastic resin substrate containing a thermoplastic resin has a fiber basis weight of 200 to 600 g / m2 on at least one surface thereof. 2 and a surface roughness Sa of the surface of the carbon fiber substrate opposite to the thermoplastic resin substrate is 1500 to 70000 nm. [2] The fiber basis weight is 250 to 400 g / m 2 and the surface roughness Sa is 1500 to 30000 nm. [3] A method for producing the intermediate material according to [1] or [2], The carbon fiber substrate is placed on at least one surface of the thermoplastic resin substrate and pressed; The hot plate pressing conditions are such that, when Tm (°C) is the melting point of the thermoplastic resin constituting the thermoplastic resin substrate, the pressing temperature is Tm+50 to Tm+90°C, or the temperature of the thermoplastic resin substrate and the carbon fiber substrate that are stacked together is Tm+20 to Tm+60°C. This is a method for producing an intermediate material. [4] The method for producing an intermediate material according to [3], wherein the pressing time is 1 to 10 minutes. [5] A method for producing a molded body, comprising pressing the intermediate material described in [1] or [2] to obtain a molded body. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an intermediate material from which a molded body having excellent mechanical properties such as bending strength can be obtained, a method for manufacturing the intermediate material, and a method for manufacturing the molded body. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing an example of an intermediate material of the present invention. [Figure 2] FIG. 4 is a cross-sectional view showing another example of the intermediate material of the present invention. [Figure 3] FIG. 2 is a diagram illustrating measurement points for the surface roughness Sa of the intermediate material in this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Intermediate material] The intermediate material of the present invention is an intermediate material used in the production of a molded product which is a laminate in which a carbon fiber reinforced resin layer is laminated on at least one surface of a thermoplastic resin layer. The intermediate material of the present invention is a thermoplastic resin substrate (hereinafter referred to as "thermoplastic resin substrate (B)") containing a carbon fiber having a fiber basis weight of 200 to 600 g / m on at least one surface thereof. 2 The carbon fiber substrate (hereinafter referred to as "carbon fiber substrate (A)") is laminated and integrated. The intermediate material is formed by hot-pressing the carbon fiber substrate (A) and the thermoplastic resin substrate (B) together at their adjacent surfaces, and they are bonded and integrated together. In the intermediate material of the present invention, the surface of the carbon fiber substrate (A) opposite to the thermoplastic resin substrate (B) has a surface roughness Sa of 1500 to 70000 nm. By further molding the intermediate material, the thermoplastic resin of the thermoplastic resin substrate is impregnated into the carbon fiber substrate, and a laminate can be formed in which a carbon fiber reinforced resin layer is laminated on at least one surface of the thermoplastic resin layer.

[0011] In the intermediate material, the carbon fiber substrate (A) may be laminated on only one surface of the thermoplastic resin substrate (B), or the carbon fiber substrate (A) may be laminated on both surfaces of the thermoplastic resin substrate (B). Specifically, as shown in Fig. 1, the intermediate material 1 may be an intermediate material in which the carbon fiber substrate (A) 12 is laminated on both surfaces of the thermoplastic resin substrate (B) 10. As shown in Fig. 2, the intermediate material 2 may be an intermediate material in which the carbon fiber substrate (A) 12 is laminated on one surface of the thermoplastic resin substrate (B) 10.

[0012] When the carbon fiber substrate (A) is laminated on both sides of the thermoplastic resin substrate (B), the surface roughness Sa is 1500 to 70000 nm on each of the surfaces of the carbon fiber substrates (A) arranged on both sides of the intermediate material opposite to the thermoplastic resin substrate (B). The carbon fiber substrate (A) may cover the entire thermoplastic resin substrate (B), or may cover the thermoplastic resin substrate (B) partially.

[0013] The carbon fiber substrate (A) is a substrate containing carbon fibers. The carbon fiber substrate (A) is preferably a substrate containing carbon fibers and thermoplastic resin fibers. The carbon fiber substrate (A) before being hot-plate pressed is preferably a substrate made of carbon fibers and thermoplastic resin fibers.

[0014] The carbon fiber is not particularly limited, and examples thereof include polyacrylonitrile (PAN) carbon fiber and PITCH carbon fiber. The carbon fiber substrate (A) may contain one type of carbon fiber or two or more types of carbon fibers.

[0015] The average fiber length of the carbon fibers is preferably 10 to 150 mm, more preferably 30 to 80 mm. When the average fiber length of the carbon fibers is equal to or greater than the lower limit of the above range, a molded product with excellent mechanical properties is easily obtained. When the average fiber length of the carbon fibers is equal to or less than the upper limit of the above range, excellent fluidity is obtained during shaping, and the thermoplastic resin easily flows between the carbon fibers. Therefore, it is easy to obtain molded products with complex three-dimensional shapes such as ribs and bosses. The average fiber length is calculated by averaging the lengths of 400 randomly selected fibers. For example, the average fiber length of carbon fibers can be calculated by measuring the fiber length of the remaining carbon fibers after burning off the resin components under a microscope.

[0016] The average fiber diameter of the carbon fibers is preferably 1 to 50 μm, more preferably 5 to 15 μm. When the average fiber diameter of the carbon fibers is equal to or greater than the lower limit of the above range, a molded product with excellent mechanical properties is easily obtained. When the average fiber diameter of the carbon fibers is equal to or less than the upper limit of the above range, moldability and shaping properties are improved. The average fiber diameter is calculated by averaging the measured fiber diameters of 400 randomly selected fibers. If the cross section of the fiber perpendicular to the fiber axis direction is not circular, for example, elliptical, the average of the major and minor axes is used as the fiber diameter. For example, the average fiber diameter of carbon fibers can be calculated by measuring the fiber diameter by observing the remaining carbon fibers under a microscope after burning off the resin component.

[0017] The carbon fiber content in the carbon fiber substrate (A) before hot plate pressing is preferably 20 to 100 mass%, more preferably 50 to 90 mass%, and even more preferably 60 to 80 mass%, based on the total mass of the carbon fiber substrate (A). When the carbon fiber content is equal to or greater than the lower limit of the above range, a molded product with excellent mechanical properties is easily obtained. When the carbon fiber content is equal to or less than the upper limit of the above range, moldability and shaping properties are improved.

[0018] The thermoplastic resin constituting the thermoplastic resin fiber is not particularly limited, and examples thereof include polyamide resins (nylon 6, nylon 66, nylon 12, nylon MXD6, etc.), polyolefin resins (low-density polyethylene, high-density polyethylene, polypropylene, etc.), modified polyolefin resins (modified polypropylene resin, etc.), polyester resins (polyethylene terephthalate, polybutylene terephthalate, etc.), polycarbonate resins, polyamideimide resins, polyphenylene oxide resins, polysulfone resins, polyethersulfone resins, polyetheretherketone resins, polyetherimide resins, polystyrene resins, ABS resins, polyphenylene sulfide resins, liquid crystal polyester resins, copolymers of acrylonitrile and styrene, and copolymers of nylon 6 and nylon 66.

[0019] An example of the modified polyolefin resin is a resin obtained by modifying a polyolefin resin with an acid such as maleic acid. As the thermoplastic resin for forming the thermoplastic resin fiber, polyolefin resin, modified polypropylene resin, polyamide resin, and polycarbonate resin are preferred from the viewpoint of the balance between adhesion to carbon fiber, impregnation into carbon fiber, and raw material cost, and polypropylene and polyamide resin are more preferred from the viewpoint of spinnability. The thermoplastic resin fibers may be formed from one type of thermoplastic resin or two or more types of thermoplastic resins.

[0020] The average fiber diameter of the thermoplastic resin fibers is preferably 20 to 150 μm, more preferably 30 to 70 μm. When the average fiber diameter of the thermoplastic resin fibers is equal to or greater than the lower limit of the above range, the fibers can be uniformly produced in the defibrating step and needle punching step, and the functions of the carbon fiber substrate (A) are exhibited. When the average fiber diameter of the thermoplastic resin fibers is equal to or less than the upper limit of the above range, moldability is improved.

[0021] The content of thermoplastic resin fibers in the carbon fiber substrate (A) before hot plate pressing is preferably 0 to 80 mass%, more preferably 10 to 50 mass%, and even more preferably 20 to 40 mass%, based on the total mass of the carbon fiber substrate (A). When the content of thermoplastic resin fibers is equal to or greater than the lower limit of the above range, moldability is improved. When the content of thermoplastic resin fibers is equal to or less than the upper limit of the above range, a molded product with excellent mechanical properties is likely to be obtained.

[0022] The fiber weight of the carbon fiber substrate (A) before hot plate pressing is 200 to 600 g / m 2 and 250-400g / m 2 When the fiber basis weight of the carbon fiber base material (A) is equal to or greater than the lower limit of the above range, a molded product having excellent mechanical properties is easily obtained. When the fiber basis weight of the carbon fiber base material (A) is equal to or less than the upper limit of the above range, moldability is improved.

[0023] The method for producing the carbon fiber substrate (A) is not particularly limited. For example, a method can be exemplified in which a mixture of cut thermoplastic resin fibers and carbon fibers is fed into a carding machine to defibrate and mix them to obtain a web, and then the webs are cross-layered and entangled by needle punching.

[0024] The thermoplastic resin substrate (B) is a substrate containing a thermoplastic resin. The thermoplastic resin substrate (B) is preferably a glass fiber reinforced resin substrate containing a thermoplastic resin and glass fibers. The thermoplastic resin substrate (B) before being hot plate pressed is preferably a glass fiber reinforced resin substrate made of glass fibers and a thermoplastic resin.

[0025] The average fiber length of the glass fibers is preferably 1 to 100 mm, more preferably 3 to 70 mm. When the average fiber length of the glass fibers is equal to or greater than the lower limit of the above range, a molded product having excellent mechanical properties is easily obtained. When the average fiber length of the glass fibers is equal to or less than the upper limit of the above range, resin impregnation and moldability are improved.

[0026] The average fiber diameter of the glass fibers is preferably 1 to 50 μm, more preferably 5 to 20 μm. When the average fiber diameter of the glass fibers is equal to or greater than the lower limit of the above range, a molded product having excellent mechanical properties such as impact resistance is easily obtained. When the average fiber diameter of the glass fibers is equal to or less than the upper limit of the above range, the fibers are less likely to break and can exhibit mechanical properties such as impact resistance.

[0027] The content of glass fibers in the thermoplastic resin substrate (B) before hot plate pressing is preferably 0 to 60 mass%, more preferably 20 to 55 mass%, and even more preferably 30 to 50 mass%, based on the total mass of the thermoplastic resin substrate (B). When the content of glass fibers is equal to or greater than the lower limit of the above range, mechanical properties such as impact resistance can be imparted. When the content of glass fibers is equal to or less than the upper limit of the above range, flowability and moldability are improved.

[0028] Examples of the thermoplastic resin contained in the thermoplastic resin substrate (B) include the same thermoplastic resins as those exemplified for the thermoplastic resin fibers of the carbon fiber substrate (A), and the preferred embodiments are also the same. The thermoplastic resin fibers contained in the carbon fiber substrate (A) and the thermoplastic resin contained in the thermoplastic resin substrate (B) may be the same thermoplastic resin or different thermoplastic resins. In terms of adhesion between the carbon fiber substrate (A) and the thermoplastic resin substrate (B), it is preferable that the thermoplastic resin fibers contained in the carbon fiber substrate (A) and the thermoplastic resin contained in the thermoplastic resin substrate (B) are the same thermoplastic resin, and it is particularly preferable that both are polypropylene. The thermoplastic resin contained in the thermoplastic resin substrate (B) may be one type or two or more types.

[0029] The content of the thermoplastic resin in the thermoplastic resin substrate (B) before hot plate pressing is preferably 40 to 100 mass%, more preferably 45 to 80 mass%, and even more preferably 50 to 70 mass%, based on the total mass of the thermoplastic resin substrate (B). When the content of the thermoplastic resin is equal to or greater than the lower limit of the above range, flowability and moldability are improved. When the content of the thermoplastic resin is equal to or less than the upper limit of the above range, mechanical properties such as impact resistance can be imparted.

[0030] The method for producing the thermoplastic resin substrate (B) is not particularly limited. For example, a method can be exemplified in which a thermoplastic resin sheet is placed on a glass fiber substrate made of glass fibers, heated and pressed, and the thermoplastic resin is melted and impregnated into the glass fiber substrate. The thermoplastic resin fiber may be mixed into the glass fiber substrate, and the thermoplastic resin sheet may be placed on top of the glass fiber substrate, heated and pressed.

[0031] The surface roughness Sa of the surface of the carbon fiber substrate (A) in the intermediate material opposite to the thermoplastic resin substrate (B) is 1500 to 70000 nm. If the surface roughness Sa of the surface is within the above range, the impregnation of the thermoplastic resin into the carbon fiber substrate (A) in the intermediate material is low. As a result, even when the carbon fiber substrate (A) springs back during preheating in the production of a molded body, the impregnation of the thermoplastic resin into the carbon fiber substrate (A) is low. Therefore, the density of the carbon fibers (fiber mass content) in the carbon fiber reinforced resin layer of the molded body is high, and the mechanical properties are improved.

[0032] The surface roughness Sa of the surface of the carbon fiber substrate (A) in the intermediate material opposite to the thermoplastic resin substrate (B) is preferably 1500 to 50000 nm, more preferably 1500 to 30000 nm. The surface roughness Sa of the intermediate material can be adjusted by adjusting the pressing conditions when the carbon fiber substrate (A) and the thermoplastic resin substrate (B) are hot-pressed. The surface roughness Sa of the intermediate material is measured at a total of six locations, with a measurement area of ​​1200 μm x 940 μm per location, and the average value is taken as the surface roughness Sa of the intermediate material. The testing machine used is a Bruker "Contour GTX" (white light interferometer), with a white light source and a magnification of 5x (objective lens) / 1x (internal lens).

[0033] As a method for producing the intermediate material of the present invention, a method of overlapping a carbon fiber substrate (A) on at least one surface of a thermoplastic resin substrate (B) and pressing (primary molding) can be mentioned. Hot plate pressing is preferable, and the conditions of the hot plate pressing are, when the melting point of the thermoplastic resin constituting the thermoplastic resin substrate is Tm (°C), the pressing temperature (temperature of the hot plate) is Tm + 50 to Tm + 90°C, or the temperature of the overlapped thermoplastic resin substrate and carbon fiber substrate is Tm + 20 to Tm + 60°C, and the pressing time is 1 to 10 minutes. For example, a thermoplastic resin substrate (B) is used as a core material, and a carbon fiber substrate (A) is placed on at least one surface of the core material. Using a press machine equipped with a pair of hot plates capable of applying pressure and heat, the carbon fiber substrate (A) and the thermoplastic resin substrate (B) are sandwiched between the hot plates and pressed so as to satisfy the above-mentioned hot plate pressing conditions, and then cooled and solidified to obtain an intermediate material. This produces an intermediate material in which the surface roughness Sa of the surface of the carbon fiber substrate (A) opposite the thermoplastic resin substrate (B) is 1500 to 70,000 nm.

[0034] The heating conditions during primary molding are preferably such that the press temperature (temperature of the hot plate) is Tm+50 to Tm+90° C., or the temperature of the stacked thermoplastic resin substrate and carbon fiber substrate is Tm+20 to Tm+60° C. This results in an intermediate material that can be used to produce a molded product with excellent mechanical properties.

[0035] The pressing time during primary molding is 1 to 10 minutes, preferably 2 to 5 minutes. If the pressing time is within the above range, an intermediate material that can be used to produce a molded product with excellent mechanical properties can be obtained.

[0036] The pressing pressure during primary molding is preferably 0.1 to 1 MPa, more preferably 0.2 to 0.4 MPa. If the pressing pressure is within the above range, an intermediate material that can be used to produce a molded product with excellent mechanical properties is likely to be obtained.

[0037] The method for cooling and solidifying the intermediate material is not particularly limited, and an example thereof is a method of pressing the intermediate material between hot plates whose temperature is equal to or lower than the melting point of the thermoplastic resin. The press temperature during cooling and solidifying of the intermediate material, that is, the temperature of the hot plate, is preferably equal to or lower than the Tm of the thermoplastic resin substrate (B). The pressing pressure when the intermediate material is cooled and solidified is preferably 0.1 to 1 MPa, more preferably 0.2 to 0.4 MPa.

[0038] [Method for manufacturing molded body] The method for producing a molded body of the present invention is a method for obtaining a molded body by hot plate pressing (secondary molding) of the intermediate material of the present invention. For example, after preheating the intermediate material of the present invention, the intermediate material is hot plate pressed by a press machine capable of applying pressure and heat and equipped with a pair of hot plates, and then cooled and solidified to obtain a molded body.

[0039] The method for preheating the intermediate material is not particularly limited, and may be, for example, heating in an oven. The temperature for preheating the intermediate material is preferably a temperature at which the temperature of the intermediate material is Tm+20 to Tm+100°C, and more preferably a temperature at which the temperature is Tm+30 to Tm+60°C. The preheating time of the intermediate material is preferably 5 to 15 minutes, more preferably 8 to 13 minutes.

[0040] The press temperature during secondary molding, that is, the temperature of the hot plate, is preferably equal to or lower than the melting point (Tm) of the thermoplastic resin. The pressing time during secondary molding is preferably 1 to 10 minutes, more preferably 3 to 6 minutes. The pressing pressure during secondary molding is preferably 1 to 10 MPa, more preferably 3 to 6 MPa.

[0041] The method for cooling and solidifying the molded body is not particularly limited, and an example thereof is a method of pressing the molded body between hot plates at a temperature equal to or lower than the melting point (Tm) of the thermoplastic resin.

[0042] As explained above, in the present invention, the carbon fiber substrate (A) and the thermoplastic resin substrate (B) are stacked and hot-pressed (primary molding) under the specific conditions to obtain an intermediate material that satisfies the specific conditions, and the intermediate material is hot-pressed (secondary molding) to obtain a molded body. By controlling the surface roughness Sa of the carbon fiber substrate (A) to a specific range in the primary molding to obtain an intermediate material, a molded body with a high carbon fiber density in the carbon fiber reinforced resin layer and excellent mechanical properties can be obtained. [Example]

[0043] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following descriptions. [Manufacturing Example 1] Unstretched polyps B Pyrene fibers cut to an average fiber length of 45 mm and PAN-based carbon fibers (filament count: 15,000, average fiber diameter: 7 μm) cut to an average fiber length of 60 mm were blended in a mass ratio of 40:60. The resulting blend was fed into a carding machine and defibrated and mixed to obtain a web. The webs were cross-layered and entangled by needle punching to obtain a fiber basis weight of 250 g / m. 2 A carbon fiber substrate (A-1) having an apparent thickness of 0.7 mm was produced.

[0044] [Manufacturing Example 2] The same procedure as in Production Example 1 was repeated except that the number of layers of the web was changed, and the fiber weight was 400 g / m 2 A carbon fiber substrate (A-2) having an apparent thickness of 1.0 mm was produced.

[0045] [Manufacturing Example 3] The same procedure as in Production Example 1 was repeated except that the number of layers of the web was changed, and the fiber weight was 650 g / m 2 A carbon fiber substrate (A-3) having an apparent thickness of 1.5 mm was produced.

[0046] [Example 1] A glass fiber composite manufactured by Quadland Plastics Composite Japan (GMT, product number: P4038-BK31, fiber mass content: 40%, average fiber diameter: 13 μm, average fiber length: 40 mm or more, thickness: 3.8 mm) was used as the thermoplastic resin substrate (B-1). The carbon fiber substrate (A-1) was placed on both sides of the thermoplastic resin substrate (B-1), and hot plate pressed under conditions of a press temperature of 210°C, a press pressure of 0.34 MPa, and a press time of 2.5 minutes. After that, the mixture was cooled and solidified using a hot plate at 25°C under a press pressure of 0.34 MPa to obtain an intermediate material having a thickness of 4.5 mm, a length of 200 mm, and a width of 200 mm.

[0047] [Examples 2 to 5] Intermediate materials were obtained in the same manner as in Example 1, except that the type of carbon fiber substrate and the molding conditions for the intermediate material were changed as shown in Table 1.

[0048] [Comparative Examples 1 to 2] Intermediate materials were obtained in the same manner as in Example 1, except that the type of carbon fiber substrate and the molding conditions for the intermediate material were changed as shown in Table 1.

[0049] [Surface roughness Sa] The surface roughness Sa of the intermediate material of each example was measured using a Bruker "Contour GTX" (white light interferometer). The measurement points for the surface roughness Sa on the surface of the intermediate material were five points: points 50 mm vertically and 50 mm horizontally from each of the four corners of the intermediate material, and the center of the intermediate material, as shown in Figure 3(A). For the back surface of the intermediate material, one point was measured at the center of the intermediate material, as shown in Figure 3(B). The surface roughness Sa measured at these six points was averaged to obtain the surface roughness Sa of the surface of the carbon fiber substrate (A) in the intermediate material.

[0050] [Impregnability] The impregnation of the thermoplastic resin into the carbon fiber base material (A) in the intermediate material of each example was evaluated by the following method. The area of ​​one side of the intermediate material is α, and the exposed area of ​​the carbon fiber base material (A) on the one side is β and do. (Evaluation criteria) 〇: 0.95<β / α≦1. △: 0.5<β / α≦0.95. ×:0<β / α≦0.5.

[0051] [Bending strength] The intermediate material obtained in each example was preheated in an oven at 215°C for 13 minutes, and then pressed with a hot plate at 80°C at a pressure of 5.0 MPa for 5 minutes to obtain a molded body with a thickness of 3 mm. A rectangular test piece measuring 3 mm thick x 80 mm long x 15 mm wide was cut out from the obtained molded body, and the three-point bending properties were measured under the following conditions. (Measurement conditions) Measuring equipment: Intesco (product name) Universal tension and compression testing machine 50kN Model 2050. In accordance with ISO14125, a three-point bending test jig (indenter radius 5 mm) was used, with the distance between supports set to 60 mm and the test speed set to 2 mm / min.

[0052] [Table 1]

[0053] As shown in Table 1, in Examples 1 to 5, where the surface roughness Sa of the intermediate material was within an appropriate range, the molded bodies obtained by secondary molding of the intermediate material had higher bending strength and superior mechanical properties than in Comparative Examples 1 and 2, where the surface roughness Sa of the intermediate material was higher. [Explanation of symbols]

[0054] 1, 2...intermediate material, 10...thermoplastic resin substrate (B), 12...carbon fiber substrate (A).

Claims

1. At least one surface of a thermoplastic resin substrate containing a thermoplastic resin is coated with a fiber basis weight of 200 to 600 g / m containing carbon fiber and thermoplastic resin fiber. ２ The carbon fiber substrates are laminated together, the carbon fiber substrate has a carbon fiber content of 60% or more, and the surface of the carbon fiber substrate opposite to the thermoplastic resin substrate has a surface roughness Sa of 1500 to 70000 nm.

2. An intermediate material as described in claim 1, wherein the thermoplastic resin substrate contains glass fiber.

3. 3. The intermediate material according to claim 1, wherein the thermoplastic resin is polypropylene.

4. The fiber basis weight is 250 to 400 g / m ２ and the surface roughness Sa is 1500 to 30000 nm.

5. A method for producing the intermediate material according to any one of claims 1 to 4, The carbon fiber substrate is placed on at least one surface of the thermoplastic resin substrate and hot-pressed; The conditions of the hot plate press are such that the melting point of the thermoplastic resin constituting the thermoplastic resin substrate is Tm (°C), and the press temperature is Tm + 50 to Tm + 90 °C, or the temperature of the superposed thermoplastic resin substrate and the carbon fiber substrate is Tm + 20 to Tm + 60 °C. A method for manufacturing an intermediate material.

6. The method for producing an intermediate material according to claim 5, wherein the pressing time is 1 to 10 minutes.

7. A method for producing a molded body, comprising pressing the intermediate material according to any one of claims 1 to 4 to obtain a molded body.

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