Carbon fiber reinforced resin pellets and methods for manufacturing the same, and carbon fiber reinforced resin molded articles and methods for manufacturing the same

Abstract

The objective is to provide carbon fiber reinforced resin pellets that can be efficiently fed even when using recycled carbon fibers, and that can produce molded products with excellent mechanical properties, and to provide carbon fiber reinforced resin molded products using the carbon fiber reinforced resin pellets. [Solution] A method for producing carbon fiber reinforced resin pellets, comprising: (i) a step of mixing carbon fibers and an ethylene / glycidyl (meth)acrylate copolymer to produce a carbon fiber bundle; and (ii) a step of supplying the carbon fiber bundle and polycarbonate resin separately to an extruder from two or more locations, kneading and extruding them to produce carbon fiber reinforced resin pellets, wherein the content of the carbon fiber bundle is 15 to 70% by mass and the content of the polycarbonate resin is 30 to 85% by mass or less, relative to the total mass of the carbon fiber reinforced resin pellets.

Description

[Technical Field]

[0001] The present invention relates to carbon fiber reinforced resin pellets and a method for producing the same, and to a carbon fiber reinforced resin molded article and a method for producing the same. [Background technology]

[0002] It is generally known that fibrous fillers such as glass fibers and carbon fibers are used to improve the mechanical properties of thermoplastic resins. In particular, polycarbonate resins blended with carbon fibers exhibit high strength. A common method for blending fibrous fillers is to melt-knead the thermoplastic resin and fibers in an extruder. The mixture of molten thermoplastic resin and fibers is extruded into strands, and the resulting pellets are used as molding raw materials for injection molding and other processes.

[0003] Generally, when manufacturing carbon fiber-reinforced resin pellets by kneading carbon fibers and thermoplastic resins, carbon fiber forms are used that facilitate handling and improve work efficiency. In particular, it is required that the supply of carbon fibers to extruders and other equipment be stable and smooth. Methods for achieving this include cutting continuous carbon fiber bundles obtained by treating them with sizing agents to create so-called chopped carbon fibers, or granulating the cut carbon fibers to form carbon fiber bundles.

[0004] As a method for manufacturing carbon fiber bundles, for example, Patent Document 1 discloses a method in which chopped carbon fibers are mixed with a sizing agent solution or suspension, granulated on an inclined rotating surface, and then dried. This yields carbon fiber bundles with high density and a streamlined shape, making it possible to stably and smoothly supply carbon fibers to extruders and the like.

[0005] On the other hand, when using thermally decomposed, cotton-like recycled carbon fibers as the raw material, the method described in Patent Document 1 cannot obtain sufficient feed efficiency. Patent Document 2 discloses a method for obtaining carbon fiber bundles using recycled carbon fibers, which involves cutting and / or crushing the recycled carbon fibers to a predetermined average length, mixing them with a solution or suspension in a mixer to form aggregates, and drying the aggregates to form spherical carbon fiber bundles.

[0006] Furthermore, Patent Document 3 discloses a method for improving the feed efficiency of carbon fibers, including recycled materials, by extruding and granulating a mixture of carbon fibers and an epoxy resin-based sizing agent to produce cylindrical carbon fiber aggregates. It also states that if the carbon fiber aggregates have a specific cylindrical shape, stable supply to an extruder using a feeder becomes possible. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Special Publication No. 10-503812 [Patent Document 2] European Patent Application Publication No. 2902433 [Patent Document 3] Patent No. 7473127 [Overview of the project] [Problems that the invention aims to solve]

[0008] The technology disclosed in Patent Document 3 is a technique for crushing and compressing carbon fibers using an extrusion granulation method, resulting in a mass of short, broken carbon fibers. Therefore, when such carbon fibers are used as raw materials, there is a problem in that the carbon fibers are further broken during processing into pellets and molded articles, impairing the mechanical properties of the molded articles.

[0009] One of the objectives of the present invention is to provide carbon fiber reinforced resin pellets that can be efficiently fed even when using recycled carbon fibers and that can produce molded articles with excellent mechanical properties, carbon fiber reinforced resin molded articles using the carbon fiber reinforced resin pellets, and methods for manufacturing the same. [Means for solving the problem]

[0010] The present invention includes the following embodiments. [1]: A method for manufacturing carbon fiber reinforced resin pellets, (i) A step of mixing carbon fibers and an ethylene / glycidyl (meth)acrylate copolymer to produce a carbon fiber bundle, (ii) A step of supplying the carbon fiber bundle and polycarbonate resin separately to an extruder from two or more locations, and kneading and extruding them to produce carbon fiber reinforced resin pellets, A method for producing carbon fiber reinforced resin pellets, wherein the carbon fiber bundle content is 15 to 70% by mass and the polycarbonate resin content is 30 to 85% by mass or less, relative to the total mass of the carbon fiber reinforced resin pellets. [2]: The method for producing carbon fiber reinforced resin pellets according to [1], wherein the extruder comprises a main raw material feeder and a side feeder. [3]: A method for producing carbon fiber reinforced resin pellets according to [2], wherein in step (ii), the polycarbonate resin is supplied from the main raw material feeder to the extruder and melted, and the carbon fiber bundle is supplied from the side feeder to the extruder. [4]: A method for producing carbon fiber reinforced resin pellets according to any one of [1] to [3], wherein the carbon fiber bundle is produced by stirring granulation in step (i). [5]: A method for producing carbon fiber reinforced resin pellets according to any one of [1] to [4], wherein the carbon fiber includes recycled carbon fiber. [6]: A method for producing carbon fiber reinforced resin pellets according to [5], wherein the amount of resin residue in the recycled carbon fiber is 5% by mass or less. [7]: A method for producing carbon fiber reinforced resin pellets according to any one of [1] to [6], wherein the carbon fiber bundle is an ellipsoidal bundle. [8]: A method for producing carbon fiber reinforced resin pellets according to any one of [1] to [7], wherein the length-weighted average fiber length of the carbon fibers contained in the carbon fiber bundle is 0.1 to 20 mm. [9]: The bulk density of the carbon fiber bundle is 0.1 to 0.7 g / cm³ 3 A method for producing carbon fiber reinforced resin pellets as described in any of [1] to [8].

[10] : A method for producing carbon fiber reinforced resin pellets according to any one of [1] to [9], wherein the angle of repose of the carbon fiber bundle is 60° or less.

[11] : A method for producing carbon fiber reinforced resin pellets according to any one of [1] to

[10] , wherein the length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin pellets is 100 μm or more.

[12] : A method for producing carbon fiber reinforced resin pellets according to any one of [1] to

[11] , wherein the length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin pellets is 100 to 500 μm.

[13] : Carbon fiber reinforced resin pellets, The carbon fiber reinforced resin pellets comprise carbon fibers, an ethylene / glycidyl (meth)acrylate copolymer, and a polycarbonate resin. The length-weighted average fiber length of the carbon fiber is 100 μm or more. Carbon fiber reinforced resin pellets, wherein the carbon fiber content is 10 to 69.9% by mass and the polycarbonate resin content is 30 to 85% by mass, relative to the total mass of the carbon fiber reinforced resin pellets.

[14] : The carbon fiber reinforced resin pellet according to

[13] , wherein the length-weighted average fiber length of the carbon fibers is 100 to 500 μm.

[15] : The carbon fiber reinforced resin pellet according to

[13] or

[14] , wherein the content of the ethylene / glycidyl (meth)acrylate copolymer is 0.1 to 10 parts by mass per 100 parts by mass of carbon fiber.

[16] : The carbon fiber reinforced resin pellet according to any one of

[13] to

[15] , wherein the carbon fiber contains recycled carbon fiber.

[17] : The carbon fiber reinforced resin pellet according to

[16] , wherein the amount of resin residue in the recycled carbon fiber is 5% by mass or less.

[18] : A carbon fiber reinforced resin molded body, which is a molded body using the carbon fiber reinforced resin pellet according to any one of

[13] to

[17] .

[19] : The carbon fiber reinforced resin molded body according to

[18] , wherein the length weighted average fiber length of the carbon fiber contained in the carbon fiber reinforced resin molded body is 100 μm or more.

[20] A method for manufacturing a carbon fiber reinforced resin molded body, including a step of molding a carbon fiber reinforced resin pellet manufactured by the manufacturing method according to any one of [1] to

[12] to obtain a fiber reinforced resin molded body.

[21] : The method for manufacturing a carbon fiber reinforced resin molded body according to

[20] , wherein the length weighted average fiber length of the carbon fiber contained in the fiber reinforced resin molded body is 100 μm or more.

[22] : A method for manufacturing a carbon fiber reinforced resin molded body, including a step of molding the carbon fiber reinforced resin pellet according to any one of

[13] to

[17] to obtain a fiber reinforced resin molded body.

[23] : The method for manufacturing a carbon fiber reinforced resin molded body according to

[22] , wherein the length weighted average fiber length of the carbon fiber contained in the fiber reinforced resin molded body is 100 μm or more.

Advantages of the Invention

[0011] According to the present invention, there are provided a carbon fiber reinforced resin pellet that can be efficiently fed even when using carbon fiber containing recycled products and can obtain a molded body with excellent mechanical properties, a carbon fiber reinforced resin molded body using the carbon fiber reinforced resin pellet, and a manufacturing method thereof.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, the present invention will be described in detail. In this specification, a numerical range indicated by "~" means a range that includes the numbers written before and after "~" as the lower and upper limits, respectively, and "A~B" means that it is greater than or equal to A and less than or equal to B.

[0013] [Carbon fiber reinforced resin pellets] One embodiment of the present invention relates to carbon fiber reinforced resin pellets. The carbon fiber reinforced resin pellets according to the embodiment contain carbon fibers, an ethylene / glycidyl (meth)acrylate copolymer, and a polycarbonate resin, wherein the length-weighted average fiber length of the carbon fibers is 100 μm or more. Furthermore, the carbon fiber content is 10 to 69.9% by mass of the total mass of the carbon fiber reinforced resin pellets, and the polycarbonate resin content is 30 to 85% by mass. A carbon fiber reinforced resin molded article can be obtained by molding carbon fiber reinforced resin pellets using the method described later in the [Method for Manufacturing a Carbon Fiber Reinforced Resin Molded Article].

[0014] <Carbon fiber> Examples of carbon fibers used in the present invention include PAN-based carbon fibers and pitch-based carbon fibers, with PAN-based carbon fibers being preferred from the viewpoint of mechanical properties. PAN-based carbon fibers are mainly composed of filament fibers made of substantially only carbon, which are produced by making fibers made of polyacrylonitrile resin polymerized with acrylonitrile as the main component infusible and then carbonizing them.

[0015] The carbon fibers contained in the carbon fiber reinforced resin pellets may include recycled carbon fibers. Even when recycled carbon fibers are included, the carbon fiber reinforced resin pellets according to this embodiment exhibit a remarkable effect of high feed efficiency to extruders and the like. Preferred examples of recycled carbon fibers include carbon fibers recovered from scraps of unidirectional prepregs, carbon fibers recovered from waste CFRP (carbon fiber reinforced polymer) made by curing unidirectional prepregs, carbon fibers recovered from scraps of SMC (sheet molding compound), and carbon fibers recovered from waste CFRP made by curing SMC. For example, by dry distilling the above-mentioned scraps or waste materials at a temperature of preferably 600°C or higher, and then heating them in an oxidizing atmosphere at, for example, 550°C or higher, preferably 600°C or higher, the matrix resin is completely thermally decomposed, and cotton-like recycled carbon fibers are obtained.

[0016] The amount of resin residue in recycled carbon fibers is preferably 5% by mass or less, and more preferably 1% by mass or less. If the amount of resin residue in recycled carbon fibers is below the above upper limit, fiber breakage is suppressed when granulation is performed by the stirring granulation method or in step (ii) described later, making it easier to obtain carbon fiber reinforced resin pellets with excellent mechanical properties. In addition, because of its excellent dispersibility in molten resin, when molding is performed using carbon fiber reinforced resin pellets, a carbon fiber reinforced resin molded article with excellent mechanical properties can be obtained.

[0017] Examples of carbon fiber forms include long fibers, chopped fibers, and milled fibers. The carbon fiber form may be one type or two or more types. Because it offers excellent feed stability and allows for easy control of the length-weighted average fiber length, it is preferable to granulate carbon fibers using a stirring granulation method and use them as carbon fiber bundles.

[0018] The length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin pellets is 100 μm or more, preferably 150 μm or more, and more preferably 200 μm or more. If the length-weighted average fiber length of the carbon fibers is above the lower limit, a carbon fiber reinforced resin molded article with excellent mechanical properties can be obtained. This is thought to be because, when molding carbon fiber reinforced resin pellets containing carbon fibers with a length-weighted average fiber length above the lower limit, the carbon fibers are oriented in the flow direction, improving the mechanical properties and elastic modulus in the flow direction of the resulting carbon fiber reinforced resin molded article. Furthermore, it is thought that the mechanical strength is also improved by improving the interfacial adhesion strength between the carbon fibers and the resin. The length-weighted average fiber length of the carbon fibers is preferably 500 μm or less, more preferably 400 μm or less, and even more preferably 300 μm or less. If the length-weighted average fiber length of the carbon fibers is below the upper limit, a carbon fiber reinforced resin molded article with excellent moldability and a good appearance can be obtained. The preferred lower and upper limits of the length-weighted average fiber length of the carbon fibers can be arbitrarily combined and, for example, can be 100-500 μm, 150-400 μm, or 200-300 μm. The length-weighted average fiber length of the carbon fibers can be adjusted, for example, by controlling the melting and kneading conditions such as the method of supplying the carbon fiber bundles, the screw rotation speed of the extruder, and the extrusion amount in step (ii) described later. The length-weighted average fiber length of the carbon fibers is measured according to the method described in the examples.

[0019] The carbon fiber content in the carbon fiber reinforced resin pellets is 10% by mass or more, preferably 13% by mass or more, and more preferably 15% by mass or more, based on the total mass of the carbon fiber reinforced resin pellets. If the carbon fiber content is above the lower limit, the mechanical strength and elastic modulus of the resulting carbon fiber reinforced resin molded article will be improved due to the reinforcing effect of the carbon fibers. The carbon fiber content in the carbon fiber reinforced resin pellets is 69.9% by mass or less, preferably 60% by mass or less, and more preferably 50% by mass or less, based on the total mass of the carbon fiber reinforced resin pellets. If the carbon fiber content is below the upper limit, the moldability will be improved, and the resulting carbon fiber reinforced resin molded article will have an excellent appearance. The preferred lower and upper limits for the carbon fiber content can be arbitrarily combined and are between 10 and 69.9% by mass, preferably 13 to 60% by mass, and more preferably 15 to 50% by mass.

[0020] <Ethylene / glycidyl (meth)acrylate copolymer> Ethylene / glycidyl (meth)acrylate copolymers can function as binder resins when forming carbon fiber bundles. Ethylene / glycidyl (meth)acrylate copolymers are copolymers having constituent units derived from ethylene and constituent units derived from glycidyl (meth)acrylate. Ethylene / glycidyl (meth)acrylate copolymers may also have constituent units derived from monomers other than ethylene and glycidyl (meth)acrylate. Other monomers include vinyl acetate, methyl acrylate, methyl methacrylate, and ethyl acrylate, for example. The proportion of ethylene-derived structural units in the ethylene / glycidyl (meth)acrylate copolymer is preferably 60 to 99% by mass relative to the total structural units.

[0021] The ethylene / glycidyl (meth)acrylate copolymer used in the present invention is not particularly limited, and examples include ethylene / glycidyl methacrylate copolymer, ethylene / glycidyl methacrylate / vinyl acetate copolymer, ethylene / glycidyl methacrylate / methyl acrylate copolymer, ethylene / glycidyl methacrylate / vinyl acetate / methyl acrylate copolymer, ethylene / glycidyl methacrylate / methyl methacrylate copolymer, ethylene / glycidyl methacrylate / vinyl acetate / methyl methacrylate copolymer, ethylene / glycidyl methacrylate / ethyl acrylate copolymer, ethylene / glycidyl methacrylate / vinyl acetate / ethyl acrylate copolymer, and ethylene / glycidyl acrylate copolymer. Examples include ethylene / glycidyl acrylate / vinyl acetate copolymer, ethylene / glycidyl acrylate / methyl acrylate copolymer, ethylene / glycidyl acrylate / vinyl acetate / methyl acrylate copolymer, ethylene / glycidyl acrylate / methyl methacrylate copolymer, ethylene / glycidyl acrylate / vinyl acetate / methyl methacrylate copolymer, ethylene / glycidyl acrylate / ethyl acrylate copolymer, ethylene / glycidyl acrylate / vinyl acetate / ethyl acrylate copolymer, ethylene / glycidyl methacrylate / glycidyl acrylate / vinyl acetate copolymer, and ethylene / glycidyl methacrylate / glycidyl acrylate / methyl acrylate copolymer. These may be used individually or as a mixture of two or more.

[0022] The ethylene / glycidyl (meth)acrylate copolymer preferably contains at least one selected from ethylene / glycidyl methacrylate copolymer, ethylene / glycidyl acrylate copolymer, ethylene / glycidyl methacrylate / methyl acrylate copolymer, and ethylene / glycidyl methacrylate / vinyl acetate copolymer. This improves the interfacial adhesion strength between the carbon fibers and the resin, thereby improving the mechanical properties of the resulting carbon fiber reinforced resin molded article. The ethylene / glycidyl (meth)acrylate copolymer preferably has a glass transition temperature of 0°C or lower. This is preferable because it avoids localized stress concentration and improves the impact resistance of the resulting carbon fiber reinforced resin molded article. Furthermore, the melting temperature and melt viscosity of the ethylene / glycidyl (meth)acrylate copolymer are preferably lower than those of the polycarbonate resin. This reduces fiber breakage in the carbon fiber reinforced pellets and the resulting carbon fiber reinforced molded article, thereby suppressing the deterioration of mechanical properties.

[0023] The content of ethylene / glycidyl (meth)acrylate copolymer in carbon fiber reinforced resin pellets is preferably 0.1 parts by mass or more, and more preferably 0.3 parts by mass or more, per 100 parts by mass of carbon fiber. If the content of ethylene / glycidyl (meth)acrylate copolymer is above the lower limit, the adhesion to carbon fiber is improved. The content of ethylene / glycidyl (meth)acrylate copolymer in carbon fiber reinforced resin pellets is preferably 5 parts by mass or less, and more preferably 1 part by mass or less, per 100 parts by mass of carbon fiber. If the content of ethylene / glycidyl (meth)acrylate copolymer is below the upper limit, a carbon fiber reinforced resin molded article with excellent mechanical properties and resistance to deformation at high temperatures can be obtained. The preferred lower and upper limits of the content of ethylene / glycidyl (meth)acrylate copolymer can be arbitrarily combined, for example, 0.1 to 5 parts by mass is preferred, and 0.3 to 1 part by mass is more preferred.

[0024] The carbon fiber bundle content in carbon fiber reinforced resin pellets is preferably 15 to 70% by mass, and more preferably 20 to 50% by mass, relative to the total mass of the carbon fiber reinforced resin pellets. If the carbon fiber bundle content is above the lower limit, the mechanical strength and elastic modulus of the carbon fiber reinforced resin molded article are improved due to the reinforcing effect of the carbon fibers. If the carbon fiber bundle content is below the upper limit, the appearance of the carbon fiber reinforced resin molded article will be excellent.

[0025] <Polycarbonate resin> Examples of polycarbonate resins used in the present invention include aromatic polycarbonate resins, aliphatic polycarbonate resins, and aromatic-aliphatic polycarbonate resins. From the viewpoint of the mechanical properties of the resulting carbon fiber reinforced resin pellets and carbon fiber reinforced resin molded articles, aromatic polycarbonate resins are preferred as the polycarbonate resin. One type of polycarbonate resin may be used alone, or two or more types may be used in combination.

[0026] Aromatic polycarbonate resins can be obtained, for example, by reacting an aromatic divalent phenol compound with phosgene or a diester carbonate. Examples of aromatic divalent phenol compounds include 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxy-3,5-diphenyl)butane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, and 1-phenyl-1,1-bis(4-hydroxyphenyl)ethane. These aromatic divalent phenol compounds may be used individually or in combination of two or more. Among the aromatic divalent phenol compounds, 2,2-bis(4-hydroxyphenyl)propane is preferred due to its excellent mechanical properties in the molded article.

[0027] The polycarbonate resin content in the carbon fiber reinforced resin pellets is 30% by mass or more, preferably 50% by mass or more, based on the total mass of the carbon fiber reinforced resin pellets. If the polycarbonate resin content is above the lower limit, carbon fiber reinforced resin pellets and carbon fiber reinforced resin molded articles with excellent moldability can be obtained. The polycarbonate resin content in the carbon fiber reinforced resin pellets is 85% by mass or less, preferably 80% by mass or less, based on the total mass of the carbon fiber reinforced resin pellets. If the polycarbonate resin content is below the upper limit, the reinforcement effect of the carbon fibers is effectively expressed, and carbon fiber reinforced resin pellets and carbon fiber reinforced resin molded articles with excellent mechanical properties can be obtained. The preferred lower and upper limits for the polycarbonate resin content can be arbitrarily combined, and are 30 to 85% by mass, preferably 50 to 80% by mass.

[0028] <Other ingredients> The carbon fiber reinforced resin pellets according to this embodiment may contain other components besides carbon fibers, ethylene / glycidyl (meth)acrylate copolymer, and polycarbonate resin, as needed, as long as they do not significantly impair the desired physical properties. Other components include, for example, resin additives such as stabilizers, release agents, pigments, dyes, UV absorbers, antistatic agents, antifogging agents, antiblocking agents, flow improvers, plasticizers, dispersants, and antibacterial agents. These other components may be used individually or in combination of two or more.

[0029] The carbon fiber reinforced resin pellets according to the embodiment described above contain carbon fibers having a specified length-weighted average fiber length, an ethylene / glycidyl (meth)acrylate copolymer, and a polycarbonate resin, and the content of carbon fibers and polycarbonate resin is controlled to specific amounts. As a result, the carbon fiber reinforced resin pellets according to the embodiment can be efficiently fed into extruders and the like even when using recycled carbon fibers, and a carbon fiber reinforced resin molded article with excellent mechanical properties can be obtained. The reason for obtaining such effects is not entirely clear, but it is thought to be as follows: The glycidyl groups of the ethylene / glycidyl (meth)acrylate copolymer chemically bond with the carbon fiber surface, and the ethylene structure of the ethylene / glycidyl (meth)acrylate copolymer is compatible with the polycarbonate resin, thereby promoting the dispersion of carbon fibers having a specified length-weighted average fiber length. This suppresses carbon fiber breakage during molding, and a carbon fiber reinforced resin molded article exhibiting excellent mechanical properties can be obtained. Furthermore, the glycidyl groups of the ethylene / glycidyl (meth)acrylate copolymer react with the polycarbonate resin to form an alloy, which improves the interfacial adhesion strength between the carbon fiber and the polycarbonate resin, thereby enhancing the mechanical properties.

[0030] [Manufacturing method for carbon fiber reinforced resin pellets] One embodiment of the present invention relates to a method for manufacturing carbon fiber reinforced resin pellets. The method for manufacturing carbon fiber reinforced resin pellets according to the embodiment includes the following steps (i) to (ii). (i) A step of mixing carbon fibers and an ethylene / glycidyl (meth)acrylate copolymer to produce a carbon fiber bundle. (ii) A step of supplying the carbon fiber bundle and polycarbonate resin separately to an extruder from two or more locations, and kneading and extruding them to produce carbon fiber reinforced resin pellets.

[0031] In process (ii), the carbon fiber bundle content is 15-70% by mass of the total mass of the carbon fiber reinforced resin pellets obtained, and the polycarbonate resin content is 30-85% by mass. The following provides a detailed explanation of each step.

[0032] <Process (i)> In step (i), carbon fibers and an ethylene / glycidyl (meth)acrylate copolymer are mixed to produce a carbon fiber bundle. This allows the carbon fiber bundle to be efficiently fed into the extruder in step (ii), even when using recycled carbon fibers.

[0033] The carbon fibers used in step (i) are the same as those exemplified in the above-mentioned [carbon fiber reinforced resin pellets], and the preferred embodiments are also the same. The carbon fibers used in step (i) may include recycled carbon fibers. When recycled carbon fibers are included, the effects of the present invention can be obtained more significantly. Examples of recycled carbon fibers include the same recycled carbon fibers exemplified in the above-mentioned [carbon fiber reinforced resin pellets], and the preferred embodiments are also the same.

[0034] The length-weighted average fiber length of the carbon fibers used in step (i) is not limited, but from the viewpoint of the mechanical properties of the resulting carbon fiber reinforced resin pellets, it is preferably 0.1 mm or more, more preferably 1 mm or more, and even more preferably 3 mm or more. Furthermore, from the viewpoint of stable supply to the extruder in the production of carbon fiber reinforced resin pellets, the length-weighted average fiber length of the carbon fibers is preferably 15 mm or less, more preferably 10 mm or less, and even more preferably 6 mm or less. The preferred lower and upper limits of the length-weighted average fiber length of the carbon fibers can be arbitrarily combined, for example, 0.1 to 15 mm is preferred, 1 to 10 mm is more preferred, and 5 to 6 mm is even more preferred. The length-weighted average fiber length of carbon fibers is calculated by taking 300 carbon fibers with a length of 50 μm or more, measuring their lengths, and using the following formula (1).

[0035]

number

[0036] The ethylene / glycidyl (meth)acrylate copolymer used in step (i) is the same as the ethylene / glycidyl (meth)acrylate copolymer exemplified in the above-mentioned [carbon fiber reinforced resin pellets], and the preferred embodiment is also the same.

[0037] Carbon fiber bundles can be produced, for example, by stirring and granulating short carbon fibers with an emulsion liquid of ethylene / glycidyl (meth)acrylate copolymer. Water may be added as needed during stirring and granulation. Short carbon fibers can be obtained, for example, by cutting the carbon fibers at predetermined intervals in the fiber direction using a rotary cutter or the like. By performing agitation granulation, even when the carbon fibers include regenerated fibers, the fibers are aligned while maintaining their length without cutting the fibers, and a carbon fiber bundle with controlled size can be produced. This allows for a more stable supply of the carbon fiber bundle to the extruder in step (ii).

[0038] The agitator used in process (i) may be a type equipped only with agitator blades, or it may have a chopper attached. If a jacketed agitator is used, the temperature of the agitator can be controlled by flowing a heat transfer medium inside the jacket.

[0039] The resulting carbon fiber bundle is preferably dried to evaporate any contained solvents such as water. This allows the ethylene / glycidyl (meth)acrylate copolymer to adhere sufficiently to the carbon fibers, easily maintaining the shape of the carbon fiber bundle. Drying may be done by natural drying or by using a hot air dryer. Using a hot air dryer is preferable from the viewpoint of strengthening the carbon fiber bundle through fusion of the carbon fibers.

[0040] The carbon fiber bundles are preferably ellipsoidal in shape. This allows for a more stable supply of the carbon fiber bundles to the extruder in step (ii). For example, by adjusting the rotational speed of the agitator blades and chopper of the stirring granulator, carbon fiber bundles that are ellipsoidal in shape can be obtained.

[0041] From the viewpoint of the mechanical properties of the resulting carbon fiber reinforced resin pellets and carbon fiber reinforced resin molded articles, the length-weighted average fiber length of the carbon fibers contained in the carbon fiber bundle is preferably 0.1 mm or more, more preferably 0.7 mm or more, even more preferably 3 mm or more, and also preferably 20 mm or less, more preferably 10 mm or less, and even more preferably 6 mm or less. The preferred lower and upper limits of the length-weighted average fiber length of the carbon fibers contained in the carbon fiber bundle can be arbitrarily combined, for example, preferably 0.1 to 20 mm, more preferably 0.7 to 10 mm, and even more preferably 3 to 6 mm. For example, by adjusting the length-weighted average fiber length of the raw material carbon fibers and the stirring granulation conditions, a carbon fiber bundle containing carbon fibers having a length-weighted average fiber length within the above range can be obtained. Furthermore, by using agitator blades and choppers without sharp surfaces in the stirring granulator and reducing the rotation speed, the decrease in the length-weighted average fiber length of the carbon fibers can be suppressed. The length-weighted average fiber length of the carbon fibers is measured according to the method described in the examples.

[0042] In process (ii), the carbon fiber bundles can be supplied to the extruder more stably, and the bulk density of the carbon fiber bundles is 0.1 g / cm³. 3 The above is preferable, 0.2 g / cm³ 3 The above is more preferable. Since the carbon fiber bundles can be prevented from clumping together in a block-like manner, the bulk density of the carbon fiber bundles is 0.7 g / cm³. 3 The following is preferable: 0.5 g / cm³ 3 The following is more preferable. The preferred lower and upper limits of the bulk density of the carbon fiber bundle can be any combination, for example, 0.1 to 0.7 g / cm³. 3 Preferably, 0.2 to 0.5 g / cm³ 3 This is more preferable. For example, by adjusting the amount and concentration of the ethylene / glycidyl (meth)acrylate copolymer emulsion liquid used in the stirring granulation process, and the time for stirring granulation, a carbon fiber bundle having the above-mentioned bulk density can be obtained. The bulk density of the carbon fiber bundle is measured according to the method described in the examples.

[0043] In step (ii), the carbon fiber bundles can be supplied to the extruder more stably, so the angle of repose of the carbon fiber bundles is preferably 60° or less, more preferably 50° or less, and even more preferably 40° or less. The lower limit of the angle of repose of the carbon fiber bundles is not particularly limited and may be, for example, 10° or more. For example, by adjusting the amount and concentration of the ethylene / glycidyl (meth)acrylate copolymer emulsion liquid used in the stirring granulation, and the time for stirring granulation, carbon fiber bundles having an angle of repose within the above range can be obtained.

[0044] The angle of repose of a carbon fiber bundle is determined by dropping a 200g carbon fiber bundle from a height of 100mm onto a horizontally held disk with a diameter of φ95mm, measuring the height of the carbon fiber bundle after 10 seconds, and calculating the angle of repose using the following formula, where R is the radius of the disk and T is the height of the bundle. Angle of repose θ=tan-1(T / R)

[0045] <Process (ii)> In process (ii), the carbon fiber bundles obtained in process (i) and polycarbonate resin are supplied separately to an extruder from two or more locations, and carbon fiber reinforced resin pellets are produced by mixing and extruding them. The polycarbonate resin used in process (ii) is the same as that exemplified in the above-mentioned [carbon fiber reinforced resin pellets], and the preferred embodiment is also the same.

[0046] Carbon fiber reinforced resin pellets can be manufactured, for example, by dry blending carbon fiber bundles and polycarbonate resin followed by melt-kneading, or by supplying carbon fiber bundles to molten polycarbonate resin and kneading. Among these methods, the method of supplying carbon fiber bundles to molten polycarbonate resin and kneading is preferred because it can suppress carbon fiber breakage, control the length-weighted average fiber length, and exhibit excellent carbon fiber dispersibility.

[0047] In step (ii), for example, an extruder equipped with a main raw material feeder and a side feeder can be used. In this case, polycarbonate resin can be supplied and melted from the main raw material feeder installed upstream of the extruder, and carbon fiber bundles can be supplied and kneaded from the side feeder installed downstream of the extruder. Furthermore, an extruder equipped with three or more feeders may be used. In this case, the polycarbonate resin may be supplied from only one location or from two or more locations. Similarly, the carbon fiber bundle may be supplied from only one location or from two or more locations.

[0048] Examples of extruders include single-screw extruders and twin-screw extruders, with twin-screw extruders being preferred. In the case of a twin-screw extruder, the screw rotation speed of the extruder is preferably 100 rpm or higher from the viewpoint of dispersing the carbon fiber bundle. Furthermore, from the viewpoint of suppressing the breakage of carbon fibers contained in the carbon fiber bundle, the screw rotation speed of the extruder is preferably 300 rpm or lower.

[0049] The extruder screw is preferably equipped with one or more kneading zones before and after the supply of carbon fiber bundles. Specifically, it is preferable to thoroughly melt the polycarbonate resin in the kneading zone before the supply of carbon fiber bundles, and then knead the molten polycarbonate resin and carbon fiber bundles in the kneading zone after the supply of carbon fiber bundles. This suppresses the breakage of carbon fibers contained in the carbon fiber bundles, makes it easier to control the length-weighted average fiber length, and allows for the production of carbon fiber-reinforced resin pellets with excellent carbon fiber dispersibility.

[0050] The temperature at which the polycarbonate resin is melted should be above the glass transition temperature of the polycarbonate resin, and is preferably between 220°C and 320°C. The mixing temperature of the polycarbonate resin and carbon fiber bundle should be above the glass transition temperature of the polycarbonate resin, preferably between 220°C and 320°C. The temperature at which the polycarbonate resin is brought to a molten state and the temperature at which the polycarbonate resin and carbon fiber bundles are mixed may be the same or different.

[0051] The length-weighted average fiber length of the carbon fibers, the carbon fiber content, and the polycarbonate resin content in the carbon fiber reinforced resin pellets produced in process (ii) are as described above in [Carbon Fiber Reinforced Resin Pellets], and the preferred embodiments are the same. The preferred range for the ethylene / glycidyl (meth)acrylate copolymer content in the carbon fiber reinforced resin pellets is also the same range as described above in [Carbon Fiber Reinforced Resin Pellets].

[0052] [Carbon fiber reinforced resin molded product] One embodiment of the present invention relates to a carbon fiber reinforced resin molded article. The carbon fiber reinforced resin molded article according to the embodiment is a molded article using the carbon fiber reinforced resin pellets described above. That is, the carbon fiber reinforced resin molded article according to the embodiment can be manufactured by molding using the carbon fiber reinforced resin pellets described above.

[0053] The length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin molded article is preferably 100 μm or more, more preferably 150 μm or more, and even more preferably 200 μm or more. If the length-weighted average fiber length of the carbon fibers is above the lower limit, a carbon fiber reinforced resin molded article with excellent mechanical properties can be obtained. Furthermore, the length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin molded article is preferably 500 μm or less, more preferably 400 μm or less, and even more preferably 300 μm or less. If the length-weighted average fiber length of the carbon fibers is below the upper limit, a carbon fiber reinforced resin molded article with excellent moldability and good appearance can be obtained. The preferred lower and upper limits of the length-weighted average fiber length of the carbon fibers can be arbitrarily combined; for example, 100 to 500 μm is preferred, 150 to 400 μm is more preferred, and 200 to 300 μm is even more preferred. The length-weighted average fiber length of the carbon fibers is measured according to the method described in the examples.

[0054] The carbon fiber bundle content in a carbon fiber reinforced resin molded article is preferably 15 to 70% by mass, and more preferably 20 to 50% by mass, relative to the total mass of the carbon fiber reinforced resin molded article. If the carbon fiber bundle content is above the lower limit, the mechanical strength and elastic modulus of the carbon fiber reinforced resin molded article are improved due to the reinforcing effect of the carbon fibers. If the carbon fiber bundle content is below the upper limit, the appearance of the carbon fiber reinforced resin molded article will be excellent. The polycarbonate resin content in the carbon fiber reinforced resin molded article is preferably 30 to 85% by mass, and more preferably 50 to 80% by mass, relative to the total mass of the carbon fiber reinforced resin molded article. If the polycarbonate resin content is within the above range, a carbon fiber reinforced resin molded article with excellent mechanical properties at high temperatures can be obtained. From the viewpoint of adhesion to carbon fibers, the content of ethylene / glycidyl (meth)acrylate copolymer in the carbon fiber reinforced resin molded article is preferably 0.1 to 5 parts by mass, and more preferably 0.3 to 1 part by mass, per 100 parts by mass of carbon fibers.

[0055] The bending strength of a carbon fiber reinforced resin molded article measured at 23°C is preferably 100 MPa or higher, more preferably 150 MPa or higher, and even more preferably 200 MPa or higher, as this yields a molded article that is less prone to cracking. The upper limit of the bending strength of a carbon fiber reinforced resin molded article measured at 23°C is not particularly limited, but may be, for example, 600 MPa or lower. The bending strength was measured in accordance with ISO 178. The test specimen used for measuring bending strength was a dumbbell-shaped tensile test specimen type A1 as described in ISO 20753. This test specimen can be formed by injection molding.

[0056] The flexural modulus of a carbon fiber reinforced resin molded article, measured at 23°C, is preferably 8000 MPa or higher, more preferably 10000 MPa or higher, and even more preferably 12000 MPa or higher, as this allows for thinner walls when designing for rigidity. The upper limit of the flexural modulus of a carbon fiber reinforced resin molded article, measured at 23°C, is not particularly limited, but may be, for example, 40000 MPa or lower. The flexural modulus was measured in accordance with JIS K7171. The test specimen used for measuring the flexural modulus was a dumbbell-shaped tensile test specimen type A1 as described in JIS K7139. This test specimen can be molded by injection molding.

[0057] The tensile strength of the carbon fiber reinforced resin molded article is preferably 70 MPa or higher, more preferably 100 MPa or higher, and even more preferably 130 MPa or higher. The upper limit of the tensile strength of the carbon fiber reinforced resin molded article is not particularly limited, but may be, for example, 400 MPa or lower. The tensile strength was measured by conducting a tensile test in accordance with JIS K7073.

[0058] The carbon fiber reinforced resin molded article according to this embodiment has excellent bending properties and can therefore be suitably used in mechanical components, electrical and electronic components, automotive parts, and the like. Furthermore, it is particularly suitable for automotive parts due to its excellent bending retention rate.

[0059] [Method for manufacturing carbon fiber reinforced resin molded articles] One embodiment of the present invention relates to a method for manufacturing a carbon fiber reinforced resin molded article. The method for manufacturing a carbon fiber reinforced resin molded article according to the embodiment is a method for obtaining a carbon fiber reinforced resin molded article by molding the carbon fiber reinforced resin pellets described above and the carbon fiber reinforced resin pellets obtained by the above manufacturing method.

[0060] Methods for molding carbon fiber reinforced resin pellets include injection molding, extrusion molding, press molding, blow molding, and rotational molding. Among these molding methods, injection molding is preferred because it offers excellent productivity for producing carbon fiber reinforced resin molded products. For injection molding, from the viewpoint of suppressing voids, a molding temperature of 220°C to 320°C is preferable. Furthermore, from the viewpoint of improving the surface appearance of the carbon fiber reinforced resin molded article, a mold temperature of 60°C to 100°C is preferable.

[0061] The length-weighted average fiber length of the carbon fibers, the carbon fiber content, and the polycarbonate resin content in the carbon fiber reinforced resin molded article produced by the manufacturing method according to the embodiment are as described in the above-mentioned [carbon fiber reinforced resin pellets], and the preferred embodiment is the same. The preferred range for the content of the ethylene / glycidyl (meth)acrylate copolymer in the carbon fiber reinforced resin pellet is also the same range as described in the above-mentioned [carbon fiber reinforced resin pellets]. [Examples]

[0062] The present invention will be described in more detail below based on examples, but the present invention is not limited in any way by the following examples.

[0063] [Raw materials] The abbreviations for the raw materials used in this example are shown below.

[0064] (binder) • E-GMA: Ethylene / glycidyl methacrylate copolymer (product name "Seporjon G515", manufactured by Sumitomo Seika Co., Ltd., emulsion liquid, solid content 40% by mass) • Polyester acrylate binder: Polyester acrylate binder solution with a solid content of 40% by mass.

[0065] (thermoplastic resin) • PC: Polycarbonate resin (product name "XANTAR7022J", manufactured by Mitsubishi Chemical Corporation)

[0066] [Agitator / mixer] A stirring granulator (product name "Intensive Mixer R08W," manufactured by Nippon Eirich Co., Ltd.) was used to manufacture the carbon fiber bundles.

[0067] [Extruder] For the production of carbon fiber reinforced resin pellets, a twin-screw extruder (model name "TEX44αII", manufactured by Japan Steel Works, Ltd.) was used. As feeders of the extruder, a main raw material feeder and a side feeder were installed from the upstream. The kneading zones of the extruder were arranged at a total of two locations, one between the main raw material feeder and the side feeder and the other between the side feeder and the die. The cylinder set temperature was set under the condition of 60 to 320°C.

[0068] [Injection molding machine] For the production of carbon fiber reinforced resin molded bodies, an injection molding machine (model name "NEX80V", manufactured by Nissei Plastic Industrial Co., Ltd.) was used. The cylinder temperature was set at 300°C and the mold set temperature was set at 100°C.

[0069] [Measurement of length-weighted average fiber length of carbon fibers] The length-weighted average fiber length of the carbon fibers contained in the carbon fiber bundle was calculated from the following formula (1) by spreading the carbon fibers obtained by thermally decomposing at 600°C for 1 hour in a nitrogen atmosphere to remove the binder on a flat surface, taking out 300 carbon fibers with a length of 50 μm or more, and measuring the fiber lengths. The length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin pellets and the length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin molded bodies were calculated from the following formula (1) by spreading the carbon fibers obtained by removing the resin using chloroform on a flat surface, taking out 300 carbon fibers with a length of 50 μm or more, and measuring the fiber lengths.

[0070] [Number]

[0071] In the above formula, L l is the length-weighted average fiber length, l i is the fiber length of the carbon fibers belonging to section i, and n i is the number of carbon fibers belonging to the said section i.

[0072] [Measurement of bulk density of carbon fiber bundle] The bulk density of the carbon fiber bundles was measured in accordance with JIS Z 2512. 100 mL of carbon fiber bundles were placed in a φ50 mm container, and the container was tapped 10 times from a height of 3 cm to deposit the carbon fiber bundles. The bulk density was then calculated from the volume and weight.

[0073] [Measurement of flexural strength and flexural modulus] For carbon fiber reinforced resin molded articles, a three-point bending test was performed at 23°C in accordance with JIS K7171, and the bending strength and bending modulus were measured.

[0074] [Tensile strength] Tensile strength was measured for carbon fiber reinforced resin molded articles by performing tensile tests in accordance with JIS K7073.

[0075] [Example 1] (Manufacturing of carbon fiber reinforced resin pellets) A carbon fiber bundle was obtained by mixing 5,000 parts by mass of recycled carbon fibers having the length-weighted average fiber length shown in Table 1, produced by thermal decomposition, with 375 parts by mass of E-GMA and 4,625 parts by mass of water in a stirring granulator, and then drying in a hot air dryer at 120°C for 1 hour. The length-weighted average fiber length of the carbon fibers contained in the carbon fiber bundle and the bulk density of the carbon fiber bundle are shown in Table 1. Next, PC was supplied to the extruder from the main raw material feeder and the carbon fiber bundles from the side feeder in the amounts shown in Table 2. The strands that came out of the die were water-cooled and then cut with a strand cutter to obtain carbon fiber reinforced resin pellets. The length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin pellets is shown in Table 2.

[0076] (Manufacturing of carbon fiber reinforced resin molded products) The obtained carbon fiber reinforced resin pellets were dried at 120°C for 7 hours, and then injection molded using an injection molding machine to obtain a plate-shaped carbon fiber reinforced resin molded body with a width of 10 mm, a length of 80 mm, and a thickness of 4 mm. Table 2 shows the length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin molded body. The resulting carbon fiber reinforced resin molded body was left to stand in a constant temperature chamber at 23°C for 24 hours, after which its bending strength, bending modulus, and tensile strength were measured. The results are shown in Table 2.

[0077] [Example 2] A carbon fiber bundle was obtained in the same manner as in Example 1, except that recycled carbon fibers having the length-weighted average fiber length shown in Table 1, which were produced by thermal decomposition, were used. The length-weighted average fiber length of the carbon fibers contained in the carbon fiber bundle and the bulk density of the carbon fiber bundle are shown in Table 1. Next, carbon fiber reinforced resin pellets were obtained using the obtained carbon fiber bundles in the same manner as in Example 1. Table 2 shows the length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin pellets. Next, a carbon fiber reinforced resin molded body was obtained using the obtained carbon fiber reinforced resin pellets in the same manner as in Example 1. Table 2 shows the length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin molded body. The resulting carbon fiber reinforced resin molded body was left to stand in a constant temperature chamber at 23°C for 24 hours, after which its bending strength, bending modulus, and tensile strength were measured. The results are shown in Table 2.

[0078] [Comparative Example 1] A carbon fiber bundle was obtained by mixing 5,000 parts by mass of recycled carbon fibers having the length-weighted average fiber length shown in Table 1, produced by thermal decomposition, with 375 parts by mass of polyester acrylate binder and 4,625 parts by mass of water in a stirring granulator, and then drying in a hot air dryer at 120°C for 1 hour. The length-weighted average fiber length of the carbon fibers contained in the carbon fiber bundle and the bulk density of the carbon fiber bundle are shown in Table 1. Next, carbon fiber reinforced resin pellets were obtained using the obtained carbon fiber bundles in the same manner as in Example 1. Table 2 shows the length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin pellets. Next, a carbon fiber reinforced resin molded body was obtained using the obtained carbon fiber reinforced resin pellets in the same manner as in Example 1. Table 2 shows the length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin molded body. The resulting carbon fiber reinforced resin molded body was left to stand in a constant temperature chamber at 23°C for 24 hours, after which its bending strength, bending modulus, and tensile strength were measured. The results are shown in Table 2.

[0079] [Comparative Example 2] Carbon fiber reinforced resin pellets were obtained in the same manner as in Comparative Example 1, except that recycled carbon fibers having the length-weighted average fiber length shown in Table 1, produced by thermal decomposition, were used. The length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin pellets is shown in Table 2. Next, a carbon fiber reinforced resin molded body was obtained using the obtained carbon fiber reinforced resin pellets in the same manner as in Example 1. Table 2 shows the length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin molded body. The resulting carbon fiber reinforced resin molded body was left to stand in a constant temperature chamber at 23°C for 24 hours, after which its bending strength, bending modulus, and tensile strength were measured. The results are shown in Table 2.

[0080] [Table 1]

[0081] [Table 2]

[0082] As shown in Tables 1 and 2, by using carbon fiber reinforced resin pellets containing carbon fibers, ethylene / glycidyl (meth)acrylate copolymer, and polycarbonate resin, and in which the length-weighted average fiber length of the carbon fibers is within a specified range, a carbon fiber reinforced resin molded article with excellent mechanical properties was obtained, which can be efficiently fed even when using recycled carbon fibers.

Claims

1. A method for manufacturing carbon fiber reinforced resin pellets, (i) A step of mixing carbon fibers and an ethylene / glycidyl (meth)acrylate copolymer to produce a carbon fiber bundle, (ii) A step of supplying the carbon fiber bundle and polycarbonate resin separately to an extruder from two or more locations, and kneading and extruding them to produce carbon fiber reinforced resin pellets, A method for producing carbon fiber reinforced resin pellets, wherein the carbon fiber bundle content is 15 to 70% by mass and the polycarbonate resin content is 30 to 85% by mass or less, relative to the total mass of the carbon fiber reinforced resin pellets.

2. The method for producing carbon fiber reinforced resin pellets according to claim 1, wherein the extruder comprises a main raw material feeder and a side feeder.

3. A method for producing carbon fiber reinforced resin pellets according to claim 2, wherein in step (ii), the polycarbonate resin is supplied from the main raw material feeder to the extruder and melted, and the carbon fiber bundle is supplied from the side feeder to the extruder.

4. A method for producing carbon fiber reinforced resin pellets according to claim 1, wherein the carbon fiber bundle is produced by stirring granulation in step (i) above.

5. The method for producing carbon fiber reinforced resin pellets according to claim 1, wherein the carbon fibers include recycled carbon fibers.

6. The method for producing carbon fiber reinforced resin pellets according to claim 5, wherein the amount of resin residue in the recycled carbon fibers is 5% by mass or less.

7. The method for producing carbon fiber reinforced resin pellets according to claim 1, wherein the carbon fiber bundle is an ellipsoidal bundle.

8. A method for producing carbon fiber reinforced resin pellets according to claim 1, wherein the length-weighted average fiber length of the carbon fibers contained in the carbon fiber bundle is 0.1 to 20 mm.

9. The bulk density of the carbon fiber bundle is 0.1 to 0.7 g / cm³. ３ The method for producing carbon fiber reinforced resin pellets according to claim 1.

10. A method for producing carbon fiber reinforced resin pellets according to claim 1, wherein the angle of repose of the carbon fiber bundle is 60° or less.

11. A method for producing carbon fiber reinforced resin pellets according to claim 1, wherein the length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin pellets is 100 μm or more.

12. A method for producing carbon fiber reinforced resin pellets according to claim 1, wherein the length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin pellets is 100 to 500 μm.

13. Carbon fiber reinforced resin pellets, The carbon fiber reinforced resin pellets comprise carbon fibers, an ethylene / glycidyl (meth)acrylate copolymer, and a polycarbonate resin. The length-weighted average fiber length of the carbon fiber is 100 μm or more. Carbon fiber reinforced resin pellets, wherein the carbon fiber content is 10 to 69.9% by mass and the polycarbonate resin content is 30 to 85% by mass, based on the total mass of the carbon fiber reinforced resin pellets.

14. The carbon fiber reinforced resin pellet according to claim 13, wherein the length-weighted average fiber length of the carbon fibers is 100 to 500 μm.

15. The carbon fiber reinforced resin pellet according to claim 13, wherein the content of the ethylene / glycidyl (meth)acrylate copolymer is 0.1 to 10 parts by mass per 100 parts by mass of carbon fiber.

16. The carbon fiber reinforced resin pellet according to claim 13, wherein the carbon fiber includes recycled carbon fiber.

17. The carbon fiber reinforced resin pellet according to claim 16, wherein the amount of resin residue in the recycled carbon fiber is 5% by mass or less.

18. A carbon fiber reinforced resin molded article, which is a molded article using carbon fiber reinforced resin pellets according to any one of claims 13 to 17.

19. The carbon fiber reinforced resin molded article according to claim 18, wherein the length-weighted average fiber length of the carbon fibers contained in the carbon fiber reinforced resin molded article is 100 μm or more.

20. A method for producing a carbon fiber reinforced resin molded article, comprising the step of molding carbon fiber reinforced resin pellets produced by the manufacturing method described in any one of claims 1 to 12 to obtain a fiber reinforced resin molded article.

21. The method for producing a carbon fiber reinforced resin molded article according to claim 20, wherein the length-weighted average fiber length of the carbon fibers contained in the fiber-reinforced resin molded article is 100 μm or more.

22. A method for producing a carbon fiber reinforced resin molded article, comprising the step of molding carbon fiber reinforced resin pellets according to any one of claims 13 to 17 to obtain a fiber reinforced resin molded article.

23. The method for producing a carbon fiber reinforced resin molded article according to claim 22, wherein the length-weighted average fiber length of the carbon fibers contained in the fiber-reinforced resin molded article is 100 μm or more.

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