Fiber-reinforced resin molded article and molding material

Abstract

A fiber-reinforced resin molded article which contains carbon fibers (A) and a thermoplastic resin (B), and which is characterized by containing 5-40 parts by weight of the carbon fibers (A) per 100 parts by weight of the total of the carbon fibers (A) and the thermoplastic resin (B) and by containing 5-40 parts by weight of the carbon fibers (A) per 100 parts by weight of the total of the carbon fibers (A) and the thermoplastic resin (B) per 100 parts by weight of the total of the carbon fibers (A) and the thermoplastic resin (B). The length ratio of the fiber lengths represented by formula 1 of 1000 carbon fibers (A) randomly selected from the molded article is 2-20 (inclusive). The length ratio of fiber length = [sigma] (L0.6) / [sigma] (L0.1)... (formula 1) L0.6: the length (mm) of the fiber having a fiber length of 0.6 mm or more, and L0.1: the length (mm) of the fiber having a fiber length of 0.1 mm or less. A fiber-reinforced resin molded article having excellent appearance quality; and a fiber-reinforced resin molding material for implementing the fiber-reinforced resin molded article.

Description

Technical Field

[0001] The present invention relates to a molded article comprising carbon fibers as reinforcing fibers and a thermoplastic resin, and a molding material comprising carbon fibers and a thermoplastic resin. Background Art

[0002] Fiber-reinforced resins, composed of reinforcing fibers and thermoplastic resins, are widely used in various industrial applications due to their lightweight and excellent mechanical properties. In particular, molded products obtained by molding pelletized materials through cost-effective and productive molding methods such as injection molding and stamping are frequently used in parts and housings for electrical and electronic equipment such as automotive components, personal computers, office automation equipment, audiovisual equipment, mobile phones, telephones, home appliances, and toys.

[0003] In particular, fiber-reinforced resins using carbon fibers as reinforcing fibers exhibit high tensile strength and elastic modulus despite being lightweight due to the excellent specific strength of carbon fibers. Therefore, they are frequently used in situations where high lightness and mechanical properties are required.

[0004] Patent Document 1 discloses a molded article having excellent mechanical properties obtained by injection molding long fiber-reinforced thermoplastic resin pellets containing at least reinforcing fibers having substantially the same length as the pellets. Furthermore, Patent Documents 2, 3, and 4 disclose molded articles having improved mechanical properties and appearance quality obtained by injection molding thermoplastic resin pellets composed of a combination of two types of reinforcing fibers, long and short, with a thermoplastic resin.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 10-138379

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2006-181776

[0009] Patent Document 3: Japanese Patent Application Publication No. 2018-162337

[0010] Patent Document 4: Japanese Patent Application Laid-Open No. 10-138244 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] However, in recent years, molded products have become smaller, thinner, and more complex, requiring molding materials to have high moldability and a high degree of balance between excellent flowability and mechanical properties that can cope with small, thin-walled, and complex shapes.

[0013] Conventionally, fiber-reinforced resin molding materials containing reinforcing fibers have tended to suffer from reduced fluidity, despite the improved mechanical properties achieved by fiber length. In particular, while carbon fibers exhibit superior specific strength and specific elastic modulus compared to other reinforcing fibers such as glass fibers, their thin fiber diameter generally leads to fiber interference during molding, making it difficult to achieve improved fluidity. However, in order to further achieve smaller, thinner, and more complex molded products, there is a demand for molded products that exhibit superior fluidity while maintaining high mechanical properties.

[0014] Therefore, in view of the above problems and needs, an object of the present invention is to provide a fiber-reinforced resin molded article having excellent fluidity and mechanical properties and further having excellent appearance quality, and a fiber-reinforced resin molding material for achieving the same.

[0015] Means for solving problems

[0016] In order to solve the above-mentioned problems, the present invention has the following configurations.

[0017] (1) A fiber-reinforced resin molded article comprising carbon fibers (A) and a thermoplastic resin (B), characterized in that the carbon fibers (A) are present in an amount of 5 to 40 parts by weight relative to a total of 100 parts by weight of the carbon fibers (A) and the thermoplastic resin (B), and that the fiber length ratio of 1000 carbon fibers (A) randomly selected from the molded article, as expressed in the following formula 1, is 2 or more and 20 or less.

[0018] Fiber length ratio = Σ(L 0.6 ) / Σ(L 0.1 )……(Formula 1)

[0019] L 0.6 : Length of fibers having a fiber length of 0.6 mm or more (mm)

[0020] L 0.1 : Length of fibers with a fiber length of 0.1 mm or less (mm)

[0021] In addition, Formula 1 can be transformed into the following formula 1-2.

[0022] Fiber length ratio = Σ(M 0.6 ×N 0.6 ) / Σ(M 0.1 ×N 0.1 )……(Formula 1-2)

[0023] M 0.6 : Length of fibers with a length of 0.6 mm or more (mm)

[0024] N 0.6 : For fibers with a length of 0.6 mm or more, the number of fibers with each length

[0025] M 0.1 : Length of fibers with a length of 0.1 mm or less (mm)

[0026] N 0.1 : For fibers with a length of 0.1 mm or less, the number of fibers with each length

[0027] (2) The fiber-reinforced resin molded article according to (1) is characterized in that, regarding the above-mentioned carbon fiber (A), the short fiber ratio represented by the following formula 2 among 1000 carbon fibers (A) randomly selected from the molded article is 15% or less.

[0028] Short fiber ratio = Σ(L 0.1 ) / Σ(Li)×100(%)......(Formula 2)

[0029] L 0.1 : Length of fibers with a fiber length of 0.1 mm or less (mm)

[0030] Li: Length of each fiber (mm)

[0031] In addition, Formula 2 can be transformed into the following formula 2-2.

[0032] Short fiber ratio = Σ(M 0.1 ×N 0.1 ) / Σ(Mi×Ni)×100(%)......(Formula 2-2)

[0033] M 0.1 :Fiber length 0.1mm or less (mm)

[0034] N 0.1 :M 0.1 The number of fibers

[0035] Mi: Length of each fiber (mm)

[0036] Ni: Number of Mi fibers

[0037] (3) The fiber-reinforced resin molded article according to claim (1) or (2), characterized in that, with respect to the above-mentioned carbon fiber (A), the width of the fiber length distribution expressed by the following formula 3 of 1000 carbon fibers (A) randomly selected from the molded article is 1.4 or more.

[0038] Width of fiber length distribution = (Σ(Li 2) / Σ(Li)) / (Σ(Li) / 1000)……(Formula 3)

[0039] Li: Length of each fiber (mm)

[0040] In addition, Formula 3 can be transformed into the following formula 3-2.

[0041] Width of fiber length distribution = (Σ(Mi 2 ×Ni) / Σ(Mi×Ni)) / (Σ(Mi×Ni) / ΣNi)……(Formula 3-2)

[0042] Mi: Length of each fiber (mm)

[0043] Ni: Number of Mi fibers

[0044] (4) The fiber-reinforced resin molded article according to any one of (1) to (3), wherein the carbon fibers (A) include recycled carbon fibers.

[0045] (5) The fiber-reinforced resin molded article according to any one of (1) to (4), characterized in that the carbon fibers (A) contained in the fiber-reinforced resin molded article include two types of carbon fibers (A-1) and carbon fibers (A-2), and the carbon fibers (A-1) and carbon fibers (A-2) have a Raman shift of 1360 cm -1 The maximum Raman scattering intensity I of the carbon fiber surface appears near 1360 , at Raman shift 1480cm -1 The minimum Raman scattering intensity I of the carbon fiber surface appears near 1480 , and at Raman shift 1580cm -1 The maximum Raman scattering intensity I of the carbon fiber surface appears near 1580 The ratio is I 1360 / I 1580 and I 1480 / I 1580 The carbon fiber (A-2) is different from the carbon fiber (A-1). 1360 / I 1580 is a larger value or the same value, and I 1480 / I 1580 is a small value.

[0046] (6) The fiber-reinforced resin molded article according to (5), wherein among the fibers with a fiber length of 0.6 mm or more among the carbon fibers (A) contained in the fiber-reinforced resin molded article, the ratio of the number of the carbon fibers (A-1) to the number of the carbon fibers (A-2), i.e., the number of (A-1) with a length of 0.6 mm or more: the number of (A-2) with a length of 0.6 mm or more, is 100:0 to 50:50.

[0047] (7) The fiber-reinforced resin molded article according to (5) or (6), characterized in that the fiber-reinforced resin molded article contains 10 to 70 parts by weight of the carbon fibers (A-2) relative to 100 parts by weight of the carbon fibers (A).

[0048] (8) The fiber-reinforced resin molded article according to any one of (5) to (7), wherein the fiber diameter of the carbon fiber (A-1) is The fiber diameter of the carbon fiber (A-2) The ratio is It is 1.2 or more and 2.0 or less.

[0049] (9) A fiber-reinforced resin molding material, which is a fiber-reinforced resin molding material (C) comprising carbon fibers (A) and a thermoplastic resin (B), characterized in that it comprises a fiber-reinforced resin molding material (C-1) and a fiber-reinforced resin molding material (C-2), wherein the fiber-reinforced resin molding material (C-1) comprises carbon fibers (CF-1) having a fiber length of 3 mm or more and 10 mm or less and oriented in the longitudinal direction of the molding material, and a thermoplastic resin (B), and the fiber-reinforced resin molding material (C-2) comprises short-fiber carbon fibers (CF-2) and a thermoplastic resin (B), and the fiber diameter of the carbon fibers (CF-1) is Fiber diameter of carbon fiber (CF-2) The ratio is It is 1.2 or more and 2.0 or less.

[0050] (10) The fiber-reinforced resin molding material according to (9) is characterized in that, regarding the above-mentioned carbon fiber (CF-2), the fiber length represented by the following formula 4 of 1000 carbon fibers (CF-2) randomly selected from the fiber-reinforced resin molding material (C-2) is greater than or equal to 0.1 mm and less than or equal to 0.4 mm.

[0051] Fiber length of carbon fiber (CF-2) = Σ(Li) / 1000 (Formula 4)

[0052] Li: Length of each fiber (mm)

[0053] In addition, Formula 4 can be transformed into the following formula 4-2.

[0054] Fiber length of carbon fiber (CF-2) = Σ(Mi×Ni) / ΣNi... (Formula 4-2)

[0055] Mi: Length of each fiber (mm)

[0056] Ni: Number of Mi fibers

[0057] (11) The fiber-reinforced resin molding material according to (9) or (10), characterized in that the fiber-reinforced resin molding material (C-1) contains, in addition to the carbon fiber (CF-1) and the thermoplastic resin (B), a compound (D) different from the thermoplastic resin (B) that exists in a state of filling between the fibers of the carbon fiber (CF-1).

[0058] (12) The fiber-reinforced resin molding material according to any one of (9) to (11), wherein the carbon fibers (CF-2) include recycled carbon fibers.

[0059] Effects of the Invention

[0060] According to the present invention, molded articles that combine thin-walled properties with complex shapes and excellent mechanical properties can be obtained. Since the molding material of the present invention can easily produce molded articles with excellent flowability and mechanical properties during molding, it can be applied to a wide range of molding methods, not only injection molding, transfer molding, blow molding, and insert molding, but also plunger molding, press molding, and stamping.

[0061] The molded articles of the present invention exhibit excellent flowability during molding while maintaining excellent mechanical properties. They can be used in automotive parts such as thrust washers, oil filters, seals, bearings, gears, cylinder head covers, bearing retainers, intake manifolds, and pedals; semiconductor / liquid crystal manufacturing equipment components such as silicon wafer carriers, IC chip trays, electrolytic capacitor trays, and insulating films; compressor components such as pumps, valves, and seals; industrial machinery components such as aircraft cabin interior components; medical device components such as sterilizers, columns, and piping; food / beverage manufacturing equipment components; and electrical / electronic equipment components and housings such as personal computers, office automation equipment, audiovisual equipment, mobile phones, telephones, home appliances, and toys. The molding material of the present invention can easily produce thin-walled molded articles as thin as 0.5 to 2 mm. The carbon fibers used as reinforcing fibers are conductive and thus impart electromagnetic shielding properties, making them suitable for electrical / electronic equipment components and housings. DETAILED DESCRIPTION

[0062] Hereinafter, the present invention will be described in detail with reference to embodiments.

[0063] <Molded products>

[0064] The molded article of the present invention comprises carbon fibers (A) and a thermoplastic resin (B). By adjusting the fiber length ratio of the carbon fibers (A) to a certain range, it is possible to retain the long carbon fibers while also including a large amount of short carbon fibers, thereby achieving both excellent mechanical properties and thin-wall properties.

[0065] [Carbon fiber (A)]

[0066] The carbon fiber (A) in the present invention will be described.

[0067] There is no particular limitation on the type of carbon fiber (A) in the present invention, but it is preferred to use carbon fibers of the PAN (polyacrylonitrile) series, pitch series, rayon series, etc. In particular, from the viewpoint of high strength, carbon fibers having a tensile strength of 3000 MPa or more are preferred, and more preferably 4000 MPa or more are more preferred. From the viewpoint of high elastic modulus, carbon fibers having a tensile elastic modulus of 200 GPa or more are preferred, and more preferably 300 GPa or more are more preferred. In particular, carbon fibers having an elastic modulus of 300 GPa or more, which are difficult to maintain a long fiber length, are preferred because they can better express the effect of the molding material of the present invention described later. The fiber diameter of the carbon fiber (A) is preferably 3 to 20 μm, more preferably 4 to 15 μm, and further preferably 4.2 to 13 μm. If the fiber diameter is less than 3 μm, the interlacing points of the fibers in the molded article increase significantly, thereby damaging the thin-walledness and surface appearance of the molded article. In addition, from the viewpoint of the economy and environmental load of the resulting molded article, it is preferred to use recycled carbon fibers in combination.

[0068] A sizing agent is preferably attached to the carbon fibers (A). By attaching a sizing agent to the carbon fibers (A), the handling efficiency during carbon fiber transfer, the processability during the production of the molding material, and the mechanical and appearance properties of the molded product can be improved. The type of sizing agent is not particularly limited; sizing agents such as epoxy resins, urethane resins, acrylic resins, and various thermoplastic resins can be used alone or in combination of two or more.

[0069] The amount of carbon fiber (A) is preferably 5 to 40 parts by weight, more preferably 8 to 35 parts by weight, and even more preferably 10 to 30 parts by weight, relative to 100 parts by weight of the molded article. If the amount of carbon fiber (A) is less than 5 parts by weight, the mechanical properties may be insufficient. If it exceeds 40 parts by weight, the carbon fiber (A) may be exposed on the surface of the molded article, thereby reducing the surface appearance.

[0070] The length ratio of the fiber length of the carbon fiber (A) in the molded article, as defined below, is 2 or more and 20 or less. It is more preferably 3 or more and 15 or less, and even more preferably 4 or more and 13 or less. When using carbon fibers, fibers with a fiber length of 0.6 mm or more have a significant effect on the impact strength of the molded article. On the other hand, the reduced fluidity caused by fiber interference during molding sometimes becomes a factor that impairs the thin-walled nature of the molded article. Fibers with a fiber length of 0.1 mm or less are less likely to cause fiber interference during molding, which can improve fluidity and thus improve the thin-walled nature of the molded article. On the other hand, the ratio of the increase in strength and elastic modulus is significantly reduced compared to fibers with a fiber length of 0.6 mm or more. Therefore, if the length ratio of the fiber length, which is the ratio of carbon fibers with a fiber length of 0.6 mm or more to carbon fibers with a fiber length of 0.1 mm or less, is less than 2, the mechanical properties sometimes become insufficient. If it exceeds 20, the carbon fibers (A) sometimes become exposed to the surface of the molded article, reducing the surface appearance.

[0071] Here, the "length ratio of fiber length" in the present invention is the ratio of fibers having a fiber length of 0.6 mm or more to fibers having a fiber length of 0.1 mm or less, as calculated by the following formula 1.

[0072] Fiber length ratio = Σ(L 0.6 ) / Σ(L 0.1 )……(Formula 1)

[0073] L 0.6 : Length of fibers having a fiber length of 0.6 mm or more (mm)

[0074] L 0.1 : The length (mm) of fibers having a fiber length of 0.1 mm or less.

[0075] The aspect ratio of the above-mentioned fiber length can be measured by the following method. Using an optical microscope with a hot stage, a test piece is appropriately cut out from the molded product, and according to the melting temperature of the thermoplastic resin (B) used, it is heated between glass plates at a hot stage appropriately set at 150 to 500°C to form a film so that the carbon fibers (A) are uniformly dispersed. The thermoplastic resin (B) is melted and observed using an optical microscope (50 to 200 times). The fiber lengths of 1000 randomly selected carbon fibers (A) are measured, and the aspect ratio is calculated by the above formula 1. Alternatively, a test piece cut out from the molded product is placed in a solvent in which the thermoplastic resin (B) is dissolved, and a heating treatment is appropriately added to prepare a solution in which the carbon fibers (A) are uniformly dispersed. The solution is then filtered, and the carbon fibers (A) dispersed on the filter paper are observed using an optical microscope (50 to 200 times). The fiber lengths of 1000 randomly selected carbon fibers (A) are measured, and the aspect ratio is calculated by the above formula 1. Examples of the filter paper used at this time include quantitative filter paper (model: No. 5C) manufactured by Adbandec Corporation.

[0076] The proportion of short fibers having a fiber length of 0.1 mm or less in the carbon fibers (A) in the molded article is preferably 15% or less. It is more preferably 10% or less, and even more preferably 5% or less. There is no particular lower limit, and it may be 0%. If the short fiber proportion exceeds 15%, mechanical properties may become insufficient.

[0077] Here, the "short fiber ratio" in the present invention is the ratio of fibers having a length of 0.1 mm or less calculated by the following formula 2.

[0078] Short fiber ratio = Σ(L 0.1 ) / Σ(Li)×100(%)......(Formula 2)

[0079] L 0.1 : Length of fibers with a fiber length of 0.1 mm or less (mm)

[0080] Li: Length of each fiber (mm).

[0081] The short fiber ratio was calculated from the above formula 2 by measuring the fiber lengths of 1000 randomly selected carbon fibers (A) in the same manner as in the measurement of the fiber length ratio.

[0082] The width of the fiber length distribution of the carbon fibers (A) in the molded article is preferably 1.4 or greater. More preferably, it is 1.5 or greater, and even more preferably, it is 1.7 or greater. The upper limit is 30. If the width of the fiber length distribution is less than 1.4, it may be difficult to achieve both mechanical properties and fluidity.

[0083] Here, the "width of fiber length distribution" in the present invention is a value calculated by the following formula 3.

[0084] Width of fiber length distribution = (Σ(Li 2 ) / Σ(Li)) / (Σ(Li) / 1000)……(Formula 3)

[0085] Li: Length of each fiber (mm).

[0086] The width of the fiber length distribution is calculated by measuring the fiber lengths of 1000 randomly selected carbon fibers (A) in the same manner as in the measurement of the aspect ratio of the fiber length, and by using the above formula 3.

[0087] The carbon fibers (A) contained in the molded article of the present invention preferably contain recycled carbon fibers. Recycled carbon fibers are carbon fibers recovered and reused from molded articles containing used carbon fibers, resin compositions containing carbon fibers, and process waste materials of molded articles.

[0088] The carbon fiber (A) in the molded article may include two or more carbon fibers having different properties such as strength, elastic modulus, fiber diameter, surface condition, and fiber length, depending on the purpose. Three or more carbon fibers may be included. In the molded article of the present invention, the carbon fiber (A) includes two types of carbon fibers (A-1) and carbon fibers (A-2) having different properties, with the carbon fiber (A-1) preferably having a fiber length of 0.6 mm or more. Furthermore, it is preferred that the carbon fiber (A-2) be a material having a shorter fiber length than the carbon fiber (A-1), so that the mechanical properties of the resulting molded article can be maintained while improving the packing properties and thin-wall properties of the fine parts.

[0089] As a method for distinguishing carbon fiber (A-1) from carbon fiber (A-2), as a method for analyzing carbon fiber, known techniques can be cited, and they can be distinguished by optical microscope observation, scanning electron microscope observation, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, etc. In the present invention, as a method for distinguishing carbon fiber (A-1) from carbon fiber (A-2), a laser Raman spectrometer is used to determine the Raman shift of 1360 cm in the obtained Raman spectrum. -1 The maximum Raman scattering intensity I of the carbon fiber surface appears near 1360 , at Raman shift 1480cm -1 The minimum Raman scattering intensity I of the carbon fiber surface appears near 1480 , and at Raman shift 1580cm -1 The maximum Raman scattering intensity I of the carbon fiber surface appears near 1580 The ratio is I 1360 / I 1580 and I 1480 / I 1580 , carbon fiber (A-2) as compared with the above carbon fiber (A-1) 1360 / I 1580 is a larger value or the same value and I 1480 / I 1580 Defined for carbon fibers with small values.

[0090] In the molded article of the present invention, the carbon fibers (A-1) and (A-2) preferably have a fiber length ratio (A-1:A-2) of 100:0 to 50:50, more preferably 100:0 to 80:20, and even more preferably 100:0. A large difference in the number ratio between the carbon fibers (A-1) and (A-2) having a fiber length of 0.6 mm or more is preferred, as this improves flowability during molding while maintaining the mechanical properties of the molded article and enhances the ability to fill fine parts.

[0091] From the perspective of reducing waste, it is preferred that the carbon fiber (A-2) of the carbon fiber (A-1) and the carbon fiber (A-2) be recycled carbon fiber. As the recycled carbon fiber, fibers produced by known production methods can be used, and for example, a method of obtaining recycled carbon fiber by performing the following steps (a) to (c) can be mentioned.

[0092] (a) A crushing step of crushing fiber-reinforced resin waste to produce crushed pieces having a predetermined fiber length.

[0093] (b) A pyrolysis treatment step of heating the crushed pieces while feeding them in a fixed amount into a pyrolysis furnace to remove the matrix resin component and obtain a pyrolyzed product.

[0094] (c) A classification process for obtaining recycled carbon fibers by classifying the fibers by fiber length after thermal decomposition.

[0095] A sizing agent may be applied to the recycled carbon fibers after the classification process.

[0096] The recycled carbon fibers are preferably contained in an amount of 10 to 70 parts by weight, more preferably 20 to 70 parts by weight, per 100 parts by weight of the carbon fibers (A). If the amount is less than 10 parts by weight, the filling of fine parts may be insufficient, while if the amount exceeds 70 parts by weight, the mechanical properties may be insufficient.

[0097] The two types of carbon fibers (A-1) and carbon fibers (A-2) included in the carbon fibers (A) preferably have different fiber diameters. The carbon fibers (A-1) are preferably larger in diameter than the carbon fibers (A-2), and more preferably the fiber diameter of the carbon fibers (A-1) is The fiber diameter of the carbon fiber (A-2) The ratio is It is 1.2 or more and 2.0 or less. It is more preferably 1.3 or more and 1.8 or less. By being within the above range, it is easy to maintain the filling property of fine parts while allowing the fiber length in the molded article to remain.

[0098] The carbon fibers (A-2) may be in a dispersed monofilament state or may include a portion of bundled fibers. The inclusion of bundled fibers improves the impact strength of the molded article compared to a dispersed monofilament state, but the bundled fibers may sometimes float to the surface of the molded article. A dispersed monofilament state is preferred; while the impact strength is slightly reduced compared to a dispersed monofilament state, the molded article exhibits excellent appearance and mechanical properties.

[0099] Furthermore, it is preferred that the carbon fibers (A-1) are derived from (CF-1) contained in the molding material (C-1) described below, and the carbon fibers (A-2) are derived from (CF-2) contained in the molding material (C-2) described below.

[0100] [Thermoplastic resin (B)]

[0101] The molded article of the present invention contains 60 to 95 parts by weight of the thermoplastic resin (B) based on 100 parts by weight of the total of the carbon fibers (A) and the thermoplastic resin (B).

[0102] In the present invention, the thermoplastic resin (B) preferably has a molding temperature (melting temperature) of 200 to 450°C. Examples thereof include polyolefin resins, polystyrene resins, polyamide resins, halogenated vinyl resins, polyacetal resins, saturated polyester resins, polycarbonate resins, polyarylsulfone resins, polyarylketone resins, polyphenylene ether resins, polyphenylene sulfide resins, polyaryletherketone resins, polyethersulfone resins, polyphenylene sulfidesulfone resins, polyarylate resins, and polyamide resins. Two or more of these resins may also be used. Among the thermoplastic resins, polyolefin resins, polyamide resins, polycarbonate resins, and polyarylsulfide resins are more preferred because they are lightweight and have an excellent balance between mechanical properties and moldability.

[0103] The so-called polyolefin resins herein include unmodified substances and modified substances. For example, unmodified polypropylene resins are specifically homopolymers of propylene, or copolymers of propylene and at least one α-olefin, conjugated diene, or non-conjugated diene. Examples of α-olefins copolymerized with propylene include ethylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 1-nonene, 1-octene, 1-heptene, 1-hexene, 1-decene, 1-undecene, and 1-dodecene, and other α-olefins having 2 to 12 carbon atoms (excluding propylene). Examples of conjugated dienes and non-conjugated dienes copolymerized with propylene include butadiene, ethylidene norbornene, dicyclopentadiene, and 1,5-hexadiene. Two or more of these may be used. The skeleton structure of the unmodified polypropylene resin includes a homopolymer of propylene, a random or block copolymer of propylene and the above-mentioned other monomers, or a random or block copolymer of propylene and other thermoplastic monomers. Suitable materials include, for example, polypropylene, ethylene / propylene copolymers, propylene / 1-butene copolymers, and ethylene / propylene / 1-butene copolymers. From the perspective of further improving the rigidity of the molded article, a homopolymer of propylene is preferred, while from the perspective of further improving the impact strength of the molded article, a random or block copolymer of propylene and the above-mentioned other monomers is preferred.

[0104] In addition, as a modified polypropylene resin, an acid-modified polypropylene resin is preferably used, and more preferably a polypropylene resin having a group of a carboxylic acid and / or a salt thereof bonded to the polymer chain. The acid-modified polypropylene resin can be obtained by various methods, for example, by graft-polymerizing a monomer having a neutralized or unneutralized carboxylic acid group and / or a monomer having a saponified or unsaponified carboxylic acid ester with a polypropylene resin. Here, examples of monomers having a neutralized or unneutralized carboxylic acid group or monomers having a saponified or unsaponified carboxylic acid ester group include, for example, ethylene-based unsaturated carboxylic acids, their anhydrides, and their esters. Furthermore, compounds having unsaturated vinyl groups other than olefins can also be used.

[0105] Examples of the ethylenically unsaturated carboxylic acid include (meth)acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, and isocrotonic acid. Examples of the anhydride thereof include nadic acid™ (endo-cis-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic acid), maleic anhydride, and citraconic anhydride.

[0106] Examples of the esters of ethylenically unsaturated carboxylic acids include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, octadecyl (meth)acrylate, stearyl (meth)acrylate, tridecyl (meth)acrylate, lauroyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and methyl methacrylate. (Meth)acrylates such as diethylaminoethyl (meth)acrylate, (meth)acrylates such as hydroxyethyl acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl acrylate, lactone-modified hydroxyethyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl acrylate; (meth)acrylates containing a hydroxy group such as glycidyl (meth)acrylate and methylglycidyl (meth)acrylate; and aminoalkyl (meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, N,N-dipropylaminoethyl (meth)acrylate, N,N-dibutylaminoethyl (meth)acrylate, and N,N-dihydroxyethylaminoethyl (meth)acrylate.

[0107] Examples of monomers having an unsaturated vinyl group other than olefins include vinyl groups containing isocyanate groups such as vinyl isocyanate and isopropenyl isocyanate; aromatic vinyl groups such as styrene, α-methylstyrene, vinyltoluene, and tert-butylstyrene; vinyl groups containing amide groups such as acrylamide, methacrylamide, N-methylolmethacrylamide, N-methylolacrylamide, diacetoneacrylamide, and maleic acid amide; vinyl esters such as vinyl acetate and vinyl propionate; unsaturated sulfonic acids such as styrenesulfonic acid, sodium styrenesulfonate, and 2-acrylamido-2-methylpropanesulfonic acid; and unsaturated phosphoric acids such as mono(2-methacryloyloxyethyl) acid phosphate and mono(2-acryloyloxyethyl) acid phosphate.

[0108] Two or more of these may be used. Among them, ethylene-based unsaturated carboxylic acid anhydrides are preferred, and maleic anhydride is more preferred.

[0109] Here, in order to improve the flexural strength and tensile strength of the molded article, it is preferred to use an unmodified polypropylene resin and a modified polypropylene resin together. In particular, from the viewpoint of the balance between flame retardancy and mechanical properties, it is preferred to use the unmodified polypropylene resin and the modified polypropylene resin in a weight ratio of 95 / 5 to 75 / 25, more preferably 95 / 5 to 80 / 20, and even more preferably 90 / 10 to 80 / 20.

[0110] In addition, polyamide resin is a resin whose main raw materials are amino acids, lactams, or diamines and dicarboxylic acids. Representative examples of its main raw materials include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and p-aminomethylbenzoic acid, lactams such as ε-caprolactam and ω-laurolactam, aliphatic diamines such as 1,4-butanediamine, 1,6-hexanediamine, 2-methyl1,5-pentanediamine, 1,9-nonanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 2,2,4- / 2,4,4-trimethyl1,6-hexanediamine, and 5-methyl1,9-nonanediamine, aromatic diamines such as m-xylylenediamine and p-xylylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, and 1-amino-3-amino Alicyclic diamines such as methyl-3,5,5-trimethylcyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, and aminoethylpiperazine; aliphatic dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid; and alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,2-cyclohexanedicarboxylic acid. Two or more of these may be used.

[0111] In the present invention, polyamide resins having a melting point of 170° C. or higher are particularly useful from the perspective of excellent heat resistance and strength. Specific examples thereof include polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polycaproamide / polyhexamethylene adipamide copolymer (nylon 6 / 66), polybutylene adipamide (nylon 46), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecanoamide (nylon 612), polydecamethylene dodecanoamide (nylon 1010), polydecamethylene dodecanoamide (nylon 1012), polydodecamethylene dodecanoamide (nylon 1212), polyundecanamide (nylon 11), polydodecaneamide (nylon 12), polyhexamethylene terephthalamide / polycaproamide copolymer (nylon 6T / 6), polyhexamethylene adipamide / polyhexamethylene terephthalamide (nylon 6T / 6), and polyhexamethylene adipamide / polyhexamethylene terephthalamide (nylon 6T / 6). Diamine copolymer (nylon 66 / 6T), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene terephthalamide copolymer (nylon 66 / 6I), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene terephthalamide copolymer (nylon 6T / 6I), polyhexamethylene terephthalamide / polyhexamethylene terephthalamide copolymer (nylon 6T / 12), polyhexamethylene terephthalamide / poly-2-methylpentamethylene terephthalamide copolymer (nylon 6T / M5T), polyphenylene adipamide (nylon XD6), polynonane terephthalamide (nylon 9T), and copolymers thereof. Two or more of these may be used. Among them, nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, and nylon 9T are more preferred.

[0112] The polymerization degree of these polyamide resins is not particularly limited. The relative viscosity of a solution of 0.25 g of the polyamide resin dissolved in 25 ml of 98% concentrated sulfuric acid measured at 25°C is preferably in the range of 1.5 to 5.0, and more preferably in the range of 2.0 to 3.5.

[0113] In addition, polycarbonate resin is to make dihydric phenol and carbonate precursor reaction and obtain.Can be the multipolymer that uses 2 kinds of above dihydric phenol or 2 kinds of above carbonate precursor to obtain.As an example of reaction method, can enumerate the solid phase transesterification method of interfacial polymerization, melt transesterification method, carbonate prepolymer and the ring-opening polymerization method of cyclic carbonate compound etc.Such polycarbonate resin itself is known, can use for example, the polycarbonate resin that Japanese Patent Laid-Open 2002-129027 communique is put down in writing.

[0114] Examples of dihydric phenols include 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, bis(4-hydroxyphenyl)alkane (bisphenol A, etc.), 2,2-bis{(4-hydroxy-3-methyl)phenyl}propane, α,α'-bis(4-hydroxyphenyl)-m-diisopropylbenzene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene. Two or more of these can be used. Among them, bisphenol A is preferred because it can produce a polycarbonate resin with better impact resistance. On the other hand, copolymers obtained using bisphenol A and other dihydric phenols are excellent in high heat resistance or low water absorption.

[0115] As the carbonate precursor, for example, an acid halide, a carbonic acid diester, or a haloformatic acid ester is used. Specific examples thereof include phosgene, diphenyl carbonate, and a dihaloformatic acid ester of a dihydric phenol.

[0116] When the polycarbonate resin is produced from the above-mentioned dihydric phenol and carbonate precursor, a catalyst, a terminal blocking agent, an antioxidant for preventing oxidation of the dihydric phenol, and the like may be used as needed.

[0117] The polycarbonate resins of the present invention include branched polycarbonate resins obtained by copolymerizing trifunctional or higher polyfunctional aromatic compounds, polyester carbonate resins obtained by copolymerizing aromatic or aliphatic (including alicyclic) difunctional carboxylic acids, copolycarbonate resins obtained by copolymerizing difunctional alcohols (including alicyclics), and polyester carbonate resins obtained by copolymerizing such difunctional carboxylic acids and difunctional alcohols. These polycarbonate resins are also well known. Two or more of these polycarbonate resins may be used.

[0118] The molecular weight of the polycarbonate resin is not particularly limited, but preferably has a viscosity average molecular weight of 10,000 to 50,000. A viscosity average molecular weight of 10,000 or greater can further improve the strength of the molded article. It is more preferably 15,000 or greater, and even more preferably 18,000 or greater. On the other hand, a viscosity average molecular weight of 50,000 or less improves moldability. It is more preferably 40,000 or less, and even more preferably 30,000 or less. When using two or more polycarbonate resins, it is preferred that at least one have a viscosity average molecular weight within the above range. In this case, a polycarbonate resin having a viscosity average molecular weight exceeding 50,000, preferably exceeding 80,000, is preferably used as the other polycarbonate resin. Such polycarbonate resins have high entropy elasticity, which is beneficial for combined use with gas-assisted molding, and also exhibits properties derived from high entropy elasticity (anti-drip properties, drawdown properties, and improved melting properties such as improved jetting).

[0119] The viscosity average molecular weight (M) of the polycarbonate resin is determined by substituting the specific viscosity (ηsp) obtained at 20° C. from a solution prepared by dissolving 0.7 g of the polycarbonate resin in 100 ml of dichloromethane into the following formula.

[0120] ηsp / c=[η]+0.45×[η] 2 c (where [η] is the intrinsic viscosity)

[0121] [η] = 1.23 × 10 -4 M 0.83

[0122] c=0.7

[0123] In the present invention, examples of the polyarylene sulfide resin include polyphenylene sulfide (PPS) resin, polyphenylene sulfide sulfone resin, polyphenylene sulfide ketone resin, and random or block copolymers thereof. Two or more of these may be used. Among them, polyphenylene sulfide resin is particularly preferably used.

[0124] The polyarylene sulfide resin can be produced by any method such as the method for obtaining a polymer having a relatively low molecular weight as described in Japanese Patent Publication No. 45-3368 or the method for obtaining a polymer having a relatively high molecular weight as described in Japanese Patent Publication No. 52-12240 or Japanese Patent Application Laid-Open No. 61-7332.

[0125] The obtained polyarylene sulfide resin can be subjected to various treatments such as crosslinking and molecular weight increase by heating in air, heat treatment in an inert gas atmosphere such as nitrogen or under reduced pressure, washing with an organic solvent, hot water, an acid aqueous solution, etc., activation with a compound containing a functional group such as an acid anhydride, amine, isocyanate, or a disulfide compound containing a functional group.

[0126] The melt viscosity of the polyarylene sulfide resin is preferably 80 Pa·s or less, more preferably 20 Pa·s or less, at 310°C and a shear rate of 1000 / s. The lower limit is not particularly limited, but is preferably 5 Pa·s or greater. Two or more polyarylene sulfide resins with different melt viscosities may be used in combination. Alternatively, the melt viscosity can be measured using a capillary rheometer (manufactured by Toyo Seiki Co., Ltd.) with a die length of 10 mm and a die hole diameter of 0.5 to 1.0 mm.

[0127] As the polyarylene sulfide resin, commercially available polyphenylene sulfide resins such as "TORELINA" (registered trademark) manufactured by Toray Industries, Ltd., "DIC.PPS" (registered trademark) manufactured by DIC Corporation, and "DIWLAFIDE" (registered trademark) manufactured by Polyplastics Corporation can also be used.

[0128] Molding materials

[0129] The fiber-reinforced resin molded article of the present invention can be produced, for example, by molding using the molding material described below using a known method. The fiber-reinforced resin molding material of the present invention comprises carbon fibers (A) and a thermoplastic resin (B). By including the carbon fibers (A), the fiber length of the carbon fibers can be maintained while maintaining fluidity, resulting in a molded article exhibiting excellent mechanical properties.

[0130] The fiber-reinforced resin molding material of the present invention comprises carbon fibers (A) and a thermoplastic resin (B). The type of thermoplastic resin (B) is not particularly limited, and examples thereof include the thermoplastic resins described in the description of the thermoplastic resin (B) for the molded article. The preferred types of thermoplastic resins are also the same, and the reasons for their preference are also the same.

[0131] The fiber-reinforced resin molded article of the present invention can be produced by molding using the following molding material using a known method. The molding material comprises a fiber-reinforced resin molding material (C-1) and a fiber-reinforced resin molding material (C-2). The fiber-reinforced resin molding material (C-1) comprises carbon fibers (CF-1) having a fiber length of 3 mm to 10 mm and oriented in the longitudinal direction of the molding material, and a thermoplastic resin (B). The fiber-reinforced resin molding material (C-2) comprises short-fiber carbon fibers (CF-2) and a thermoplastic resin (B). Preferably, the fiber-reinforced resin molding material (C-1) as so-called long-fiber pellets and the fiber-reinforced resin molding material (C-2) as short-fiber pellets are dry-blended and provided for molding. This allows for easy adjustment of the content of carbon fibers (A-1) derived from the carbon fibers (CF-1) contained in the molding material (C-1) and the content of carbon fibers (A-2) derived from the carbon fibers (CF-2) contained in the molding material (C-2). Dry blending, as used herein, differs from blending involving melt kneading and refers to stirring and mixing multiple materials at a temperature at which the resin component does not melt, to achieve a substantially uniform state. This is preferably used when pelletized molding materials are used, such as in injection molding and extrusion molding.

[0132] The carbon fibers (CF-1) contained in the molding material (C-1) and the carbon fibers (CF-2) contained in the molding material (C-2) preferably have different fiber diameters. The carbon fibers (CF-1) are preferably larger in diameter than the carbon fibers (CF-2). Fiber diameter of carbon fiber (CF-2) The ratio is The carbon fiber (CF-1) is preferably 1.2 or more and 2.0 or less. It is preferably 1.3 or more and 1.8 or less. The above range is preferred because it can suppress breakage of the carbon fiber (CF-1) during molding and appropriately control the fiber length ratio, short fiber ratio, and fiber length distribution width in the molded product. By suppressing breakage of the carbon fiber (CF-1) and producing fibers with a fiber length of less than 0.1 mm, high mechanical properties can be achieved even with a small amount of carbon fiber (CF-1) content.

[0133] Molding material (C-1)

[0134] The type of carbon fiber (CF-1) contained in the fiber-reinforced resin molding material (C-1) comprising carbon fibers (CF-1) having a fiber length of 3 mm or more and 10 mm or less and oriented in the longitudinal direction of the molding material and a thermoplastic resin (B) is not particularly limited, and examples thereof include the carbon fibers described in the description of the carbon fibers (A) of the molded article. The length of the carbon fibers (CF-1) is 3 to 10 mm. Preferably, it is 5 to 9 mm. The carbon fibers (CF-1) are preferably in a state where single fibers are arranged in one direction. Preferred forms include unidirectional fiber bundles, bidirectional fiber bundles, and multidirectional fiber bundles, but from the perspective of productivity in the process of manufacturing the molding material, unidirectional fiber bundles can be more preferably used. Since the more single fibers of the carbon fibers (CF-1) the more economical it is, when the molding material is formed into, for example, pellets, the number of single fibers in one pellet is preferably 10,000 or more. On the other hand, since the more monofilaments with carbon fiber, the more disadvantageous the impregnation of the matrix resin, the more it is from the perspective of seeking both economic efficiency and impregnation, it is more preferably 15,000 or more and 100,000 or less, and it is particularly preferred to use 20,000 or more and 50,000 or less. In addition, the carbon fiber (CF-1) is preferably in the molding material, and the carbon fiber (CF-1) is aligned along the length direction of the molding material, and the length of the carbon fiber (CF-1) is substantially the same as the length of the molding material. Here, the so-called alignment along the length direction of the molding material refers to the state in which the axis of the long axis of the carbon fiber (CF-1) points to the same direction as the axis of the long axis of the molding material, and the angle offset between the axes is preferably 20° or less, more preferably 10° or less, and further preferably 5° or less. In addition, the so-called substantially the same length, for example, in a granular molding material, is that the carbon fiber (CF-1) is not cut midway inside the particle, or substantially does not contain carbon fiber (CF-1) that is significantly shorter than the total length of the particle. The total pellet length refers to the length of the carbon fibers (CF-1) in the pellet in the orientation direction. By making the carbon fibers (CF-1) substantially the same length as the molding material, the carbon fibers in the molded product can be made longer, resulting in superior mechanical properties and dimensional accuracy.

[0135] The fiber-reinforced resin molding material (C-1) of the present invention preferably contains, in addition to the carbon fibers (CF-1) and the thermoplastic resin (B), a compound (D) different from the thermoplastic resin (B) that fills the spaces between the fibers of the carbon fibers (CF-1). The presence of the compound D filling the spaces between the fibers improves the dispersibility of the fibers during molding and suppresses fiber breakage during molding.

[0136] The above-mentioned compound (D) preferably has a low melt viscosity compared to the thermoplastic resin (B). The melt viscosity of the compound (D) is lower than that of the thermoplastic resin (B), so that when the molding material is molded, the fluidity of the compound (D) is high, and the dispersion effect of the carbon fiber (CF-1) into the thermoplastic resin (B) can be further improved, and the loss of the fiber can be suppressed. In addition, the compound (D) preferably has a high affinity with the thermoplastic resin (B). By selecting an impregnated resin with a high affinity with the thermoplastic resin (B), it is compatible with the thermoplastic resin (B) efficiently during molding, and therefore the dispersibility of the carbon fiber can be further improved.

[0137] The compound (D) is preferably a resin selected from epoxy resins, phenolic resins, and terpene resins, and may be a homopolymer or a reaction product with other components. Pre-impregnation of the carbon fiber (CF-1) with the compound (D) improves dispersibility efficiently during molding, and is therefore preferably used.

[0138] The number average molecular weight of compound (D) is preferably 200 to 5000. If the number average molecular weight is 200 or more, the flexural strength and tensile strength of the molded article can be further improved. The number average molecular weight is more preferably 1000 or more. In addition, if the number average molecular weight is 5,000 or less, the viscosity of the compound is moderately low, so the impregnation property into the carbon fiber (A-1) is excellent, and the dispersibility of the carbon fiber in the molded article can be further improved. The number average molecular weight is more preferably 3,000 or less. In addition, the number average molecular weight of such a compound can be measured using gel permeation chromatography (GPC).

[0139] The compound (D) is preferably used in an amount of 0.1 to 20 parts by weight, more preferably 3 to 10 parts by weight, relative to 100 parts by weight of the molding material (C-1). Within this range, a molding material having excellent moldability and handleability can be obtained.

[0140] Molding material (C-2)

[0141] The type of carbon fiber (CF-2) contained in the fiber-reinforced resin molding material (C-2) containing short-fiber carbon fibers (CF-2) and a thermoplastic resin (B) is not particularly limited, and examples thereof include the carbon fibers described in the description of the carbon fibers (A) of the molded article.

[0142] The molding material (C-2) is obtained by melt-kneading a thermoplastic resin (B) and carbon fibers. The form of the carbon fiber raw material used in the melt-kneading is not particularly limited as long as it can be put into a melt-kneading device. Examples include pre-cut chopped strands, crushed fibers, continuous fibers, etc. From the perspective of productivity, chopped strands can be preferably used. As chopped strands, recycled chopped strands obtained by crushing a fiber-reinforced resin molding and pyrolyzing the matrix resin can be used. As a method for obtaining recycled chopped strands, it can be obtained by a known method.

[0143] The fiber length of the carbon fiber (CF-2) contained in the molding material (C-2) is preferably 0.1 to 0.4 mm, more preferably 0.2 to 0.4 mm. When the fiber length of the carbon fiber (CF-2) is less than 0.1 mm, the mechanical properties of the molded article may become insufficient. On the other hand, when the fiber length of the carbon fiber (CF-2) is 0.4 mm or more, the fluidity during molding may become insufficient.

[0144] Here, the "fiber length of carbon fibers (CF-2)" contained in the molding material (C-2) in the present invention refers to the number average fiber length calculated by the following formula 4.

[0145] Fiber length of carbon fiber (CF-2) = Σ(Li) / 1000 (Formula 4)

[0146] Li: length of each fiber (mm).

[0147] The fiber length of the carbon fiber (CF-2) can be measured using the method described in the method for measuring the fiber length of carbon fibers contained in the molded article. The fiber lengths of 1000 randomly selected carbon fibers (CF-2) are measured, and the fiber length is calculated using the above formula 4.

[0148] The fiber-reinforced resin molding material of the present invention may also contain recycled carbon fibers, similarly to the above-mentioned molded article. Preferably, the carbon fibers (CF-2) contain recycled carbon fibers.

[0149] Example

[0150] The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to the description of these Examples. First, the evaluation methods of various properties used in these Examples will be described.

[0151] (1) Fiber length ratio of carbon fibers (A) in molded products

[0152] The test piece cut from the molded product was placed in a solvent in which the thermoplastic resin (B) used in each example and comparative example was dissolved, and a heat treatment was appropriately added to obtain a solution in which the carbon fibers (A) were uniformly dispersed. The solution was then filtered using a quantitative filter paper (No. 5C) manufactured by Adbandec Corporation, and the carbon fibers (A) dispersed on the filter paper were observed using an optical microscope (50 to 200 times). The fiber lengths of 1,000 randomly selected carbon fibers (A) were measured, and the fiber length ratio, expressed as the ratio of fibers with a length of 0.6 mm or more to fibers with a length of 0.1 mm or more, was calculated using the following formula 1.

[0153] Fiber length ratio = Σ(L 0.6 ) / Σ(L 0.1 )……(Formula 1)

[0154] L 0.6 : Length of fibers having a fiber length of 0.6 mm or more (mm)

[0155] L 0.1 : The length (mm) of fibers having a fiber length of 0.1 mm or less.

[0156] (2) Short fiber ratio of carbon fiber (A) in molded products

[0157] The carbon fibers (A) were observed using an optical microscope (50-200 times magnification) in the same manner as in (1) above. The fiber lengths of 1000 randomly selected carbon fibers (A) were measured, and the short fiber ratio, represented by the ratio of fibers with a length of 0.1 mm or less, was calculated using the following formula 2.

[0158] Short fiber ratio = Σ(L 0.1 ) / Σ(Li)×100(%)......(Formula 2)

[0159] L 0.1 : Length of fibers with a fiber length of 0.1 mm or less (mm)

[0160] Li: Length of each fiber (mm).

[0161] (3) Width of fiber length distribution of carbon fibers (A) in molded products

[0162] The carbon fibers (A) were observed using an optical microscope (50-200 times magnification) in the same manner as in (1) above. The fiber lengths of 1000 randomly selected carbon fibers (A) were measured, and the width of the fiber length distribution was calculated using the following formula 3.

[0163] Width of fiber length distribution = (Σ(Li 2 ) / Σ(Li)) / (ΣLi / 1000)……(Formula 3)

[0164] Li: Length of each fiber (mm).

[0165] (4) Ratio of the number of fibers having a fiber length of 0.6 mm or more in the carbon fiber (A-1) and the carbon fiber (A-2) in the molded article

[0166] The carbon fiber (A) was observed using an optical microscope (50-200 times) in the same manner as in (1) above. The fiber lengths of 400 randomly selected carbon fibers (A) were measured, and fibers with a fiber length of 0.6 mm or more were selected. The selected fibers were measured using a laser Raman spectrophotometer, and the Raman shift of the obtained Raman spectrum at 1360 cm was quantified. -1 The maximum Raman scattering intensity of the carbon fiber surface appears near the Raman shift of 1480 cm -1 The minimum Raman scattering intensity of the carbon fiber surface appears near the Raman shift of 1580 cm -1 The carbon fiber (A-1) and the carbon fiber (A-2) are identified by the ratio of the maximum values ​​of the Raman scattering intensity appearing on the carbon fiber surface near the carbon fiber, thereby calculating the ratio of the number of fibers with a fiber length of more than 0.6 mm in the carbon fiber (A-1) and the carbon fiber (A-2).

[0167] (5) Charpy impact strength measurement of molded products

[0168] The parallel portion of the ISO dumbbell test piece obtained in each example and comparative example was cut out and subjected to a V-notched Charpy impact test in accordance with ISO 179 using a C1-4-01 testing machine manufactured by Tokyo Test Machinery Co., Ltd. The impact strength (kJ / cm 2 The calculated values ​​were judged according to the following criteria, and A and B were considered acceptable.

[0169] A: 11KJ / m 2 above

[0170] B: 9KJ / m 2 Above and less than 11KJ / m 2

[0171] C: less than 9KJ / m 2 .

[0172] (6) Determination of flexural strength and flexural modulus of molded products

[0173] The bending properties of ISO dumbbell test pieces obtained by injection molding the molding material were measured in accordance with ISO 178 (1993). A 3-point bending test fixture (indenter radius 5 mm) was used with the fulcrum distance set to 64 mm, and the bending modulus was measured under the test conditions of a test speed of 2 mm / min. As the testing machine, an "Instron (registered trademark)" universal testing machine model 5566 (manufactured by Instron Co., Ltd.) was used. The following criteria were used for judgment, and A and B were set as qualified.

[0174] Bending strength

[0175] A: 410MPa or above

[0176] B: 380MPa or more and less than 410MPa

[0177] C: 330MPa or more and less than 380MPa

[0178] D: 260MPa or more and less than 330MPa

[0179] E: less than 260 MPa.

[0180] Flexural modulus

[0181] A: 22GPA or above

[0182] B: 21GPa or more and less than 22GPa

[0183] C: 17 MPa or more and less than 21 GPa

[0184] D: less than 17MPa.

[0185] (7) Determination of tensile strength of molded products

[0186] Regarding the ISO dumbbell test pieces obtained by injection molding the molding material, the bending properties were measured in accordance with ISO527 (1993). The bending modulus was measured using a tensile test fixture with the distance between the fixtures set to 115 mm at a test speed of 5 mm / min. As the testing machine, an "Instron (registered trademark)" universal testing machine 5566 (manufactured by Instron Co., Ltd.) was used. The following criteria were used for judgment, with A and B being qualified.

[0187] A: 260MPa or above

[0188] B: 240MPa or more and less than 260MPa

[0189] C: 200 MPa or more and less than 240 MPa

[0190] D: 160MPa or more and less than 200MPa

[0191] E: less than 160MPa

[0192] (8) Fiber length in molding material (C-2)

[0193] A test piece selected from the molding material (C-2) was placed in a solvent containing the thermoplastic resin (B) used in each example and comparative example, and then heated as appropriate to obtain a solution in which the carbon fibers (A) were uniformly dispersed. The solution was then filtered using quantitative filter paper (No. 5C) manufactured by Adbandek Co., Ltd., and the carbon fibers (CF-2) dispersed on the filter paper were observed using an optical microscope (50-200x magnification). The fiber length of 1,000 randomly selected carbon fibers (A) was measured and calculated using the following formula 4.

[0194] Fiber length of carbon fiber (CF-2) = Σ(Li) / 1000 (Formula 4)

[0195] Li: length of each fiber (mm).

[0196] (9) Fluidity of molding materials

[0197] The molding material was injection molded using an injection molding machine using a mold with a width of 10 mm, a length of 125 mm, and a t of 2 mm. The injection molding process was performed at an injection speed of 30 mm / s, a back pressure of 10 MPa, a holding pressure of 40 MPa, a cylinder temperature of 260°C, and a mold temperature of 80°C to produce molded products. The peak cylinder pressure at this point was used as an indicator of fluidity. The cylinder pressure was calculated as the average of 20 injections and used in the evaluation of each example and comparative example. The following criteria were used for evaluation, with grades A and B being considered acceptable.

[0198] A: less than 90MPa

[0199] B: 90MPa or more and less than 110MPa

[0200] C: 110 MPa or more.

[0201] Reference Example 1

[0202] Production of carbon fiber (CF-1)

[0203] For carbon fibers "Toreka" (registered trademark) manufactured by Toray Industries, Inc. (total number of filaments: 24,000, single fiber diameter: 7 μm), a sizing agent mother solution containing glycerol polyglycidyl ether, a multifunctional compound, dissolved in water was prepared to provide 2% by weight. The sizing agent was applied to the carbon fibers by an immersion method and then dried at 230°C. The carbon fibers thus obtained had a sizing agent adhesion of 1.0% by weight.

[0204] Reference Example 2

[0205] Preparation of carbon fiber (CF-2)-(1)

[0206] A sizing agent mother solution containing glycerol polyglycidyl ether, a multifunctional compound, dissolved in water to provide 2% by weight of "Toreka" (registered trademark) carbon fiber T700S-24000 (total number of filaments: 24,000, single fiber diameter: 7 μm) was prepared. The sizing agent was applied to the carbon fibers by an immersion method and then dried at 230°C. The resulting carbon fibers had a sizing agent adhesion of 1.0% by weight. The resulting carbon fibers were cut using a drum cutter to obtain chopped carbon fibers with a chopped length of 6 mm.

[0207] Reference Example 3

[0208] Preparation of carbon fiber (CF-2)-(2)

[0209] Carbon fiber reinforced plastic (CFRP) molded articles, produced by applying a pressure of 0.6 MPa to a press and heating at 160°C for 2 hours using carbon fiber "Toreka" (registered trademark) prepreg P3252S-12 (single fiber diameter 7μm) manufactured by Tore Co., Ltd., were crushed and classified to obtain scrap CFRP sheets. The scrap CFRP sheets were evenly spread on a metal plate and placed in a 59-liter electric muffle furnace. While nitrogen was introduced into the furnace, the temperature was maintained at 500°C for 3.5 hours. Subsequently, recycled carbon fiber chopped strands were obtained by similarly introducing air into the furnace while maintaining the temperature at a predetermined temperature (300°C) for 2 hours.

[0210] Reference Example 4

[0211] Preparation of carbon fiber (CF-2)-(3)

[0212] Carbon fiber reinforced plastic (CFRP) molded articles, produced by applying a pressure of 0.6 MPa to a press and heating at 160°C for 2 hours using carbon fiber "Toreka" (registered trademark) prepreg P2252S-12 (single fiber diameter 5μm) manufactured by Tore Co., Ltd., were crushed and classified to obtain scrap CFRP sheets. The scrap CFRP sheets were evenly spread on a metal plate and placed in a 59-liter electric muffle furnace. While nitrogen was introduced into the furnace, the temperature was maintained at 500°C for 3.5 hours. Subsequently, recycled carbon fiber chopped strands were obtained by similarly introducing air into the furnace while maintaining the temperature at a predetermined temperature (300°C) for 2 hours.

[0213] Reference Example 5

[0214] Preparation of carbon fiber (CF-2)-(4)

[0215] Carbon fiber reinforced plastic (CFRP) molded products were crushed and classified as waste CFRP by applying a pressure of 0.6 MPa to carbon fiber "Toreka" (registered trademark) prepreg P2252S-12 (single fiber diameter 5μm) manufactured by Tore Co., Ltd. in a press and heating at 160°C for 2 hours. The waste CFRP sheets were evenly spread on a metal plate and placed in a 59-liter electric muffle furnace. While nitrogen was introduced into the furnace, the treatment temperature was maintained at 400°C for 1 hour. Then, while air was introduced into the furnace, the treatment temperature was maintained at a predetermined temperature (300°C) for 1 hour, and recycled carbon fiber chopped strands were obtained. Some of the fibers in the resulting recycled carbon fiber chopped strands were bound together by the residual resin in the CFRP, forming bundles.

[0216] <Thermoplastic resin (B)>

[0217] Used:

[0218] (B-1) Polyamide 6 resin (nylon 6 resin "Amira" (registered trademark) CM1001 manufactured by Toray Industries, Ltd.)

[0219] (B-2) Polycarbonate resin ("Mitsubishi Electric Co., Ltd. "Mitsubishi Polycarbonate" (registered trademark) S-3000")

[0220] (B-3) A product obtained by blending a polypropylene resin ("Platinum Polymer Co., Ltd. "Platinum Polymer" (registered trademark) J137G) and a maleic acid-modified polypropylene resin ("Admar" (registered trademark) QE840" manufactured by Mitsui Chemicals, Inc.) at a weight ratio of 90 / 10.

[0221] <Compound (D)>

[0222] Used:

[0223] (D-1) Terpene phenol resin ("YS Terpene N125" manufactured by Teresa Rubber Co., Ltd.)

[0224] (D-2) Bisphenol A type epoxy resin ("jER (registered trademark) 1004AF" manufactured by Mitsubishi Chemical Co., Ltd.)

[0225] (D-3) Hydrogenated terpene resin (manufactured by Tossupler Co., Ltd., "Coronor" (registered trademark) P125).

[0226] (Example 1)

[0227] A long fiber-reinforced resin pellet production apparatus was used, using a TEX-30α twin-screw extruder (screw diameter 30 mm, L / D = 32) manufactured by Japan Steel Works, Ltd., equipped with a coating die for wire resin coating methods at the tip. The extruder barrel temperature was set at 230°C, and the thermoplastic resin (B-1) described above was supplied from the main hopper and melt-kneaded at a screw speed of 200 rpm. The compound (D-1), heated and melted at 250°C, was discharged at a rate of 6 parts by weight relative to a total of 100 parts by weight of the carbon fibers (CF-1) and the thermoplastic resin (B-1). Then, the compound (D-1) is discharged and impregnated into a fiber bundle composed of carbon fibers (CF-1). Then, a fiber bundle of carbon fibers (CF-1) to which the compound (D-1) is applied is supplied to a die hole (3 mm in diameter) from which molten thermoplastic resin (B-1) is discharged, and the fiber bundle is continuously arranged so that the thermoplastic resin (B) covers the periphery of the carbon fibers (CF-1). At this time, in the internal cross section of the fiber bundle, at least a portion of the carbon fibers (CF-1) is in contact with the thermoplastic resin (B-1). After the obtained strand is cooled, it is cut into pellets of 7 mm in length using a cutter to prepare a fiber-reinforced resin molding material (C-1)-(1). At this time, the pulling speed is adjusted so that the carbon fibers (CF-1) are 30 parts by weight relative to a total of 100 parts by weight of (CF-1) and (B-1). The length of the carbon fibers (CF-1) in the obtained fiber-reinforced resin molding material (C-1)-(1) is substantially the same as the pellet length, and the carbon fiber bundle is arranged parallel to the axial direction of the molding material.

[0228] Next, after feeding the thermoplastic resin (B-1) into the main hopper of another twin-screw extruder (TEX30α manufactured by Japan Steel Works, Ltd.), the carbon fiber (CF-2)-(1) was fed into the molten resin from a side feeder, and the screw speed was set to 200 rpm. The strands discharged from the die were cooled in water, cut into 3.0 mm long strands by a strand pelletizer, and pelletized to obtain a fiber-reinforced resin molding material (C-2)-(1). At this time, the amount of carbon fiber (CF-2)-(1) fed was adjusted so that the carbon fiber (CF-2)-(1) was 30 parts by weight relative to the total of 100 parts by weight of (CF-2)-(1) and (B-1).

[0229] The fiber-reinforced resin molding materials (C-1)-(1) and (C-2)-(1) thus obtained were dry-blended in the ratios shown in Table 1 to obtain a fiber-reinforced resin molding material (C) serving as an intermediate raw material. The fiber-reinforced resin molding material (C) thus obtained was injection molded using an injection molding machine (J110AD, manufactured by Japan Steel Works, Ltd.) under the conditions of injection speed: 30 mm / s, back pressure: 10 MPa, holding pressure: 40 MPa, holding time: 10 seconds, cylinder temperature: 260°C, and mold temperature: 80°C. ISO-type dumbbell test pieces were prepared as molded products, and the cylinder peak pressure during molding was measured, measuring 10 mm wide × 125 mm × 2 mm thick. The composition ratios of carbon fiber (CF-1), carbon fiber (CF-2), thermoplastic resin (B-1), and compound (D) shown in Table 1 were adjusted to the dry-blending ratio. Here, the barrel temperature refers to the temperature of the portion of the injection molding machine where the molding material is heated and melted, and the mold temperature refers to the temperature of the mold into which the resin is injected to form the desired shape. The resulting test pieces (molded products) were allowed to stand for 24 hours in a constant temperature and humidity chamber maintained at 23°C and 50% RH before being evaluated for properties. The results of the evaluations conducted using the above methods are summarized in Table 1.

[0230] (Examples 2 to 11, Comparative Examples 1 to 6)

[0231] A material and a molded article were obtained in the same manner as in Example 1 except that the ratios of the components were as shown in Tables 1 to 3.

[0232] (Example 12)

[0233] A long fiber-reinforced resin pellet production apparatus was used, using a TEX-30α twin-screw extruder (screw diameter 30 mm, L / D = 32) manufactured by Japan Steel Works, Ltd., equipped with a coating die for wire resin coating methods at the tip. The extruder barrel temperature was set to 300°C, and the thermoplastic resin (B-2) described above was supplied from the main hopper and melt-kneaded at a screw speed of 200 rpm. The discharge rate of the compound (D-2), heated and melted at 250°C, was adjusted to 6 parts by weight per 100 parts by weight of the total of the carbon fibers (CF-1) and the thermoplastic resin (B-2). Then, the compound (D-2) is discharged and impregnated into a fiber bundle composed of carbon fibers (CF-1). Then, the fiber bundle of carbon fibers (CF-1) to which the compound (D-2) is applied is supplied to a die hole (3 mm in diameter) from which the molten thermoplastic resin (B-2) is discharged, and the fiber bundle is continuously arranged so that the thermoplastic resin (B-2) covers the periphery of the carbon fibers (CF-1). At this time, in the internal cross section of the fiber bundle, at least a portion of the carbon fibers (CF-1) is in contact with the thermoplastic resin (B-2). After the obtained strands are cooled, they are cut into pellets with a cutter to form a 7 mm length, thereby producing fiber-reinforced resin molding materials (C-1)-(2). At this time, the pulling speed is adjusted so that the carbon fibers (CF-1) are 30 parts by weight relative to the total of 100 parts by weight of (CF-1) and (B-2). The length of the carbon fibers (CF-1) in the obtained fiber-reinforced resin molding materials (C-1)-(2) is substantially the same as the pellet length, and the carbon fiber bundles are arranged parallel to the axial direction of the molding material.

[0234] Next, after feeding the thermoplastic resin (B-2) into the main hopper of another twin-screw extruder (TEX30α manufactured by Japan Steel Works, Ltd.), carbon fibers (CF-2)-(3) were fed into the molten resin from a side feeder, and the screw speed was set to 200 rpm. The strands discharged from the die were cooled in water, cut into 3.0 mm long strands by a strand pelletizer, and pelletized to obtain a fiber-reinforced resin molding material (C-2)-(2). At this time, the amount of carbon fibers (CF-2)-(3) fed was adjusted so that the carbon fibers (CF-2)-(3) were 30 parts by weight relative to a total of 100 parts by weight of (CF-2)-(3) and (B-2).

[0235] The fiber-reinforced resin molding materials (C-1) and (C-2) thus obtained were dry-blended in the ratios shown in Table 4 to obtain a fiber-reinforced resin molding material (C) serving as an intermediate raw material. The fiber-reinforced resin molding material (C) thus obtained was injection molded using an injection molding machine (J110AD, manufactured by Japan Steel Works, Ltd.) under the conditions of an injection speed of 30 mm / s, a back pressure of 10 MPa, a holding pressure of 40 MPa, a holding time of 10 seconds, a cylinder temperature of 300°C, and a mold temperature of 80°C. ISO-type dumbbell test pieces were prepared as molded products, and the cylinder peak pressure during molding, measuring 10 mm wide x 125 mm wide x 2 mm thick, was measured. The composition ratios of carbon fiber (CF-1), carbon fiber (CF-2), thermoplastic resin (B), and compound (D) shown in Table 4 were adjusted based on the dry-blending ratios. Here, the barrel temperature refers to the temperature of the portion of the injection molding machine where the molding material is heated and melted, and the mold temperature refers to the temperature of the mold into which the resin is injected to form the desired shape. The resulting test pieces (molded products) were allowed to stand for 24 hours in a constant temperature and humidity chamber maintained at 23°C and 50% RH before being evaluated for properties. The results of the evaluations conducted using the above methods are summarized in Table 4.

[0236] (Comparative Example 7)

[0237] A material and a molded article were obtained in the same manner as in Example 12 except that the ratios of the components were as shown in Table 4.

[0238] (Example 13)

[0239] A long fiber-reinforced resin pellet production apparatus was used, using a TEX-30α twin-screw extruder (screw diameter 30 mm, L / D = 32) manufactured by Japan Steel Works, Ltd., equipped with a coating die for wire resin coating methods at the tip. The extruder barrel temperature was set at 220°C, and the thermoplastic resin (B-3) described above was supplied from the main hopper and melt-kneaded at a screw speed of 200 rpm. The discharge rate of the compound (D-3), heated and melted at 200°C, was adjusted to 6 parts by weight per 100 parts by weight of the total of the carbon fibers (CF-1) and the thermoplastic resin (B-3). Then, the compound (D-3) is discharged and impregnated into a fiber bundle composed of carbon fibers (CF-1). Then, a fiber bundle of carbon fibers (CF-1) to which the compound (D-3) is applied is supplied to a die hole (3 mm in diameter) from which the molten thermoplastic resin (B-3) is discharged, and the fiber bundle is continuously arranged so that the thermoplastic resin (B-3) covers the periphery of the carbon fibers (CF-1). At this time, in the internal cross section of the fiber bundle, at least a portion of the carbon fibers (CF-1) is in contact with the thermoplastic resin (B-3). After the obtained strands are cooled, they are cut into pellets with a cutter to form a 7 mm length, thereby producing fiber-reinforced resin molding materials (C-1) to (3). At this time, the pulling speed is adjusted so that the carbon fibers (CF-1) are 30 parts by weight relative to a total of 100 parts by weight of (CF-1) and (B-3). The length of the carbon fibers (CF-1) in the obtained fiber-reinforced resin molding materials (C-1) to (3) is substantially the same as the pellet length, and the carbon fiber bundles are arranged parallel to the axial direction of the molding material.

[0240] Next, after feeding the thermoplastic resin (B-3) into the main hopper of another twin-screw extruder (TEX30α manufactured by Japan Steel Works, Ltd.), carbon fibers (CF-2)-(3) were fed into the molten resin from a side feeder, and the screw speed was set to 200 rpm. The strands discharged from the die were cooled in water, cut into 3.0 mm long strands by a strand pelletizer, and pelletized to obtain a fiber-reinforced resin molding material (C-2)-(3). At this time, the amount of carbon fibers (CF-2)-(3) fed was adjusted so that the carbon fibers (CF-2)-(3) were 30 parts by weight relative to a total of 100 parts by weight of (CF-2)-(3) and (B-3).

[0241] The fiber-reinforced resin molding materials (C-1) and (C-2) thus obtained were dry-blended in the ratios shown in Table 4 to obtain a fiber-reinforced resin molding material (C) serving as an intermediate raw material. The fiber-reinforced resin molding material (C) thus obtained was injection molded using an injection molding machine (J110AD, manufactured by Japan Steel Works, Ltd.) under the conditions of injection speed: 30 mm / s, back pressure: 10 MPa, holding pressure: 40 MPa, holding time: 10 seconds, cylinder temperature: 230°C, and mold temperature: 60°C. ISO-type dumbbell test pieces were prepared as molded products, and the cylinder peak pressure during molding, measuring 10 mm wide × 125 mm × 2 mm thick, was measured. The composition ratios of carbon fiber (A-1), carbon fiber (A-2), thermoplastic resin (B), and compound (D) shown in Table 1 were adjusted to the dry-blending ratio. Here, the barrel temperature refers to the temperature of the portion of the injection molding machine where the molding material is heated and melted, and the mold temperature refers to the temperature of the mold into which the resin is injected to form the desired shape. The resulting test pieces (molded products) were allowed to stand for 24 hours in a constant temperature and humidity chamber maintained at 23°C and 50% RH before being evaluated for properties. The results of the evaluations conducted using the above methods are summarized in Table 4.

[0242] (Comparative Example 8)

[0243] A material and a molded article were obtained in the same manner as in Example 13 except that the ratios of the components were as shown in Table 4.

[0244]

[0245]

[0246] Table 3

[0247]

[0248] Table 4

[0249]

[0250] Examples 1 and 2 showed excellent mechanical properties and fluidity. Example 3, due to the use of recycled carbon fiber chopped strands, showed slightly inferior mechanical properties compared to Example 2, but still exhibited excellent mechanical properties. Examples 4 to 7 also showed excellent mechanical properties and fluidity even when the fiber type was changed. They also showed the same mechanical properties as Examples 1 to 3 even when the amount of recycled carbon fiber chopped strands was increased. Examples 8 to 11 showed slightly inferior mechanical properties and fluidity compared to Examples 4 to 7, but exhibited excellent mechanical properties and fluidity. Examples 12 and 13 showed excellent mechanical properties and fluidity even when the resin type was changed, although slightly inferior to Example 5.

[0251] On the other hand, Comparative Example 1 shows that the aspect ratio of the carbon fiber (A) in the molded product is small, resulting in poor bending strength. The reason is that the ratio of the fiber diameters of the carbon fiber (CF-1) and the carbon fiber (CF-2) in the molding material (C) is small, so the fiber breakage during molding increases the proportion of short fibers. Comparative Examples 2 and 3 also show that the aspect ratio of the carbon fiber (A) in the molded product is small, resulting in poor mechanical properties. The reason is that the proportion of carbon fiber (A-2) in the carbon fiber (A) is large, and the proportion of carbon fiber (A-1) with a long fiber length is reduced. Comparative Examples 4 and 5 do not contain molding material (C-1), so the carbon fibers in the molded products are short, resulting in poor mechanical properties. Comparative Example 6 does not contain molding material (C-2), so there are few short carbon fibers in the molded product, resulting in poor fluidity. Comparative Examples 7 and 8 do not contain molding material (C-1), so the carbon fibers in the molded products are short, resulting in poor mechanical properties.

Claims

1. A fiber-reinforced resin molded article comprising carbon fibers (A) and a thermoplastic resin (B), characterized in that: The carbon fiber (A) is contained in an amount of 5 to 40 parts by weight relative to 100 parts by weight of the total of the carbon fiber (A) and the thermoplastic resin (B); and the carbon fiber (A) has an aspect ratio represented by the following formula 1 of 1000 carbon fibers (A) randomly selected from the molded article of 2 or more and 20 or less. Fiber length ratio = Σ(L 0.6 ) / Σ(L 0.1 )···Formula 1 L 0.6 : The length of the fiber having a fiber length of 0.6 mm or more, in mm, L 0.1 : The length of fibers having a fiber length of 0.1 mm or less, the unit of which is mm.

2. The fiber-reinforced resin molded article according to claim 1, wherein Regarding the carbon fiber (A), the ratio of short fibers represented by the following formula 2 in 1000 carbon fibers (A) randomly selected from the molded article is 15% or less, Short fiber ratio = Σ(L 0.1 ) / Σ(Li)×100(%)···Formula 2 L 0.1 : The length of the fiber with a fiber length of 0.1 mm or less, in mm, Li: The length of each fiber, in mm.

3. The fiber-reinforced resin molded article according to claim 1, wherein Regarding the carbon fibers (A), the width of the fiber length distribution represented by the following formula 3 of 1000 carbon fibers (A) randomly selected from the molded article is 1.4 or more, Width of fiber length distribution = (Σ(Li 2 ) / Σ(Li)) / (ΣLi / 1000)···Equation 3 Li: The length of each fiber, in mm.

4. The fiber-reinforced resin molded article according to claim 1, wherein The carbon fibers (A) include recycled carbon fibers.

5. The fiber-reinforced resin molded article according to claim 1, wherein The carbon fibers (A) contained in the fiber-reinforced resin molded article include two types of carbon fibers (A-1) and carbon fibers (A-2), and the carbon fibers (A-1) and carbon fibers (A-2) have a Raman shift of 1360 cm -1 The maximum Raman scattering intensity I of the carbon fiber surface appears near 1360 , at Raman shift 1480cm -1 The minimum Raman scattering intensity I of the carbon fiber surface appears near 1480 , and at Raman shift 1580cm -1 The maximum Raman scattering intensity I of the carbon fiber surface appears near 1580 The ratio is I 1360 / I 1580 and I 1480 / I 1580 Different, the carbon fiber (A-2) is different from the carbon fiber (A-1), 1360 / I 1580 is a larger value or the same value, and I 1480 / I 1580 is a small value.

6. The fiber-reinforced resin molded article according to claim 5, wherein, among the fibers having a fiber length of 0.6 mm or greater among the carbon fibers (A) contained in the fiber-reinforced resin molded article, a ratio of the number of the carbon fibers (A-1) to the carbon fibers (A-2), i.e., the number of (A-1) fibers having a length of 0.6 mm or greater: the number of (A-2) fibers having a length of 0.6 mm or greater, is 100:0 to 50:

50.

7. The fiber-reinforced resin molded article according to claim 5, wherein: The carbon fibers (A-2) are contained in an amount of 10 to 70 parts by weight relative to 100 parts by weight of the carbon fibers (A).

8. The fiber-reinforced resin molded article according to claim 5, wherein The fiber diameter of the carbon fiber (A-1) The fiber diameter of the carbon fiber (A-2) The ratio is It is 1.2 or more and 2.0 or less.

9. A fiber-reinforced resin molding material, which is a fiber-reinforced resin molding material (C) comprising carbon fibers (A) and a thermoplastic resin (B), characterized in that: The invention comprises a fiber-reinforced resin molding material (C-1) and a fiber-reinforced resin molding material (C-2), wherein the fiber-reinforced resin molding material (C-1) comprises carbon fibers (CF-1) having a fiber length of 3 mm or more and 10 mm or less and oriented in the longitudinal direction of the molding material, and a thermoplastic resin (B), and the fiber-reinforced resin molding material (C-2) comprises short-fiber carbon fibers (CF-2) and a thermoplastic resin (B), wherein the fiber diameter of the carbon fibers (CF-1) is Fiber diameter of carbon fiber (CF-2) The ratio is It is 1.2 or more and 2.0 or less.

10. The fiber-reinforced resin molding material according to claim 9, wherein Regarding the carbon fiber (CF-2), the fiber length represented by the following formula 4 of 1000 carbon fibers (CF-2) randomly selected from the fiber-reinforced resin molding material (C-2) is 0.1 mm or more and 0.4 mm or less, Fiber length of carbon fiber (CF-2) = Σ(Li) / 1000 ···Equation 4 Li: The length of each fiber, in mm.

11. The fiber-reinforced resin molding material according to claim 9, wherein The fiber-reinforced resin molding material (C-1) contains, in addition to the carbon fibers (CF-1) and the thermoplastic resin (B), a compound (D) different from the thermoplastic resin (B) that fills the spaces between the fibers of the carbon fibers (CF-1).

12. The fiber-reinforced resin molding material according to claim 9, wherein The carbon fiber (CF-2) includes recycled carbon fiber.

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