Resin composition containing carbon fiber

Abstract

To provide a carbon fiber-containing resin composition, containing a thermoplastic resin and a carbon fiber, which provides molded resin products with low anisotropy, excellent dimensional stability, and high flexural strength.SOLUTION: A carbon fiber-containing resin composition, contains a carbon fiber kneaded in a thermoplastic resin, wherein the carbon fiber has an average length of 50 to 150 μm, the content of the carbon fiber is 3 to 9 mass% relative to the content of the thermoplastic resin, and the carbon fiber-containing resin composition has a flexural strength of at least 4000 Mpa.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a carbon fiber-containing resin composition.

Background Art

[0002] There is a technique of finely cutting carbon fibers from the fibrous state and adding them to a thermoplastic resin. It is already known that by adding several mass% of carbon fibers to a thermoplastic resin, the strength of the material is improved, and particularly the flexural modulus is greatly improved.

[0003] By the way, carbon fibers finely cut from the fibrous state have an aspect ratio. For example, the length of the carbon fibers after cutting is in the size range of 3 mm to 200 μm (0.2 mm). When the length (fiber direction) is 200 μm and the thickness is 5 μm, the aspect ratio (length / diameter) is 40 (see FIG. 1). When carbon fibers having such an aspect ratio are added to a thermoplastic resin and the resulting resin composition is heated and melted and molded, the carbon fibers tend to be arranged along the flow direction of the material. In that case, after the resin composition is cured, there is a problem that the molding shrinkage rate of the molded body is different in the flow direction of the material and the direction perpendicular to the flow of the material.

[0004] The problem of the different molding shrinkage rates of this molded body will be described with reference to FIG. 2. FIG. 2 shows a flat molded body molded using a molten resin composition. When the material is put in a heat-melted state from the upper right of FIG. 2 and molded by cooling, the carbon fibers tend to be arranged along the flow direction of the material (red arrow in the figure) (blue line in the figure), and there is a problem that the molding shrinkage rate of the molded body is different in the resin flow direction (Y) and the direction perpendicular to the resin flow (X). In this example, when carbon fibers are added, the molding shrinkage rate of the molded body tends to be smaller in the resin flow direction (Y) than when carbon fibers are not added. This is because the Y direction is the direction in which the fibers are inserted, so the molded body does not shrink, resulting in a smaller shrinkage rate. On the other hand, in the X direction, since the fibers are not inserted, the molded body shrinks more easily than in the Y direction, and the shrinkage rate is larger than in the Y direction. This situation is called anisotropy in the molding shrinkage rate. When the anisotropy is significant, it causes dimensional errors in the molded body, which becomes a problem.

[0005] In Patent Document 1, for the purpose of improving anisotropy, in a resin molding material having carbon fiber (A) and a thermoplastic resin (B) as essential components, as the carbon fiber (A), carbon fiber (a1) having a Young's modulus of 150 GPa or less and a diameter in the range of 10 μm to 20 μm, and carbon fiber (a2) having a diameter in the range of 0.1 μm to 5 μm are contained at a ratio such that the total mass of (a1) and (a2) is 95% by mass or more of the total mass of the carbon fiber (A). A resin molding material is disclosed.

Summary of the Invention

Problems to be Solved by the Invention

[0006] What is described in Patent Document 1 uses two types of carbon fibers with different diameters, and there is a problem that two types of carbon fibers must be prepared.

[0007] An object of the present invention is to provide a carbon fiber-containing resin composition containing a thermoplastic resin and carbon fibers, which can provide a resin molded body having low anisotropy, excellent dimensional stability, and high flexural strength.

Means for Solving the Problems

[0008] The above problems can be solved by a carbon fiber-containing resin composition having the following configuration. A carbon fiber-containing resin composition obtained by kneading carbon fibers into a thermoplastic resin, The average length of the carbon fiber is 50 μm or more and 150 μm or less, the content of the carbon fiber with respect to the thermoplastic resin is 3% by mass or more and 9% by mass or less, the flexural strength of the carbon fiber-containing resin is 4000 Mpa or more, and a carbon fiber-containing resin composition characterized by the above.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a carbon fiber-containing resin composition capable of providing a resin molded body having low anisotropy, excellent dimensional stability, and high flexural strength.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0011] The carbon-containing resin composition of the present invention can improve the problem of molding shrinkage rate while maintaining strength such as flexural modulus by adjusting the length and content of carbon fibers added to the thermoplastic resin. In particular, by improving the problem of anisotropy of the molding shrinkage rate caused by the alignment of carbon fibers along the flow of the resin during the molding of the carbon fiber-containing resin composition, a molded body with excellent dimensional stability can be produced. Hereinafter, the carbon-containing resin composition of the present invention will be described.

[0012] (Carbon fiber-containing resin composition) The resin composition constituting the resin molded body contains a thermoplastic resin (e.g., PC / ABS) and carbon fiber as components. The resin composition optionally contains a flame retardant, an antioxidant, and other additives.

[0013] (Thermoplastic resin) The following thermoplastic resins can be used. (PC resin) The polycarbonate resin (PC resin) may be, for example, an aromatic homopolycarbonate resin or a copolycarbonate resin obtained by reacting an aromatic dihydric phenol compound with phosgene or a carbonic acid diester. Examples of the aromatic dihydric phenol compound 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, etc. These may be used alone or as a mixture.

[0014] (ABS resin) The manufacturing method of ABS resin (acrylonitrile-butadiene-styrene copolymer resin) is not particularly limited. For example, an emulsion polymerization method in which monomers of styrene and acrylonitrile in an emulsified state are mixed with rubber in an emulsified state and polymerized; a bulk suspension polymerization method in which rubber is dissolved in monomers of styrene and acrylonitrile and bulk polymerized, and during the polymerization, this polymerization solution is suspended in water and the polymerization is continued under suspension polymerization conditions, etc. can be used for manufacturing. When alloying PC resin, PVC resin, PBT resin, etc., a polymerization method corresponding to the properties of the ABS resin used is selected. Generally, for ABS resins manufactured by either the emulsion polymerization method or the bulk suspension polymerization method, alloying is possible.

[0015] <<PC / ABS resin>> PC / ABS resin is a mixed resin of PC resin (polycarbonate resin) and ABS resin (acrylonitrile-butadiene-styrene copolymer resin). Also, instead of PC / ABS resin, a block copolymer of PC resin and ABS resin may be used.

[0016] <<Recycled material>> The above resins may use recycled materials (recovered materials). As an example, recycled materials include plastics recovered from products such as printers. However, it may also be market recovered materials recovered from the market. For example, it may include recycled materials of home appliances such as air conditioners, TVs, refrigerators, washing machines, and used OA equipment.

[0017] <Carbon fiber> As the carbon fiber, commercially available ones can be used. Hereinafter, "carbon fiber" may be referred to as "CF" or "carbon fiber". As CF, new materials (virgin materials) may be used, or recycled materials may be used. Generally, new materials (virgin materials) have less variation in quality. However, due to the high recycling technology of CF in recent years and the fact that recycled materials also have little variation in quality, it is no problem to use recycled materials. In addition, recycled materials are more effective than new materials (virgin materials) in terms of environmental impact and cost.

[0018] As CF, various types and shapes are sold. This CF is kneaded with a thermoplastic resin, and the kneaded material is injection-molded to form a molded body. This molded body is used for parts such as printers, and since the quality required for each part is different, the type and shape of CF are appropriately selected according to the required specifications.

[0019] In Example 1 of the present application described later, CF with a fiber length of about 3 mm and a fiber thickness of 1 to 10 μm, which is generally available from Carbon Fiber Recycling Industry Co., Ltd., was used. CF other than the above size is also generally available. The CF was adjusted to a length of about 3 mm by finely cutting it from the fibrous state. When the length is about 3 mm or more, entanglement or aggregation of the fibers occurs during kneading with the thermoplastic resin, making kneading difficult. On the other hand, when the length is shorter than about 3 mm, it is difficult to cut, resulting in higher costs.

[0020] Also, as CF, mild fiber carbon fiber may be used. Mild fiber CF is a material in a short fibrous state and in a powdery form when visually confirmed. In Example 2 of the present application described later, as mild fiber carbon fiber, a material with a fiber length of about 25 μm and a fiber thickness of 1 to 10 μm was used. Fibers with a length of about 25 μm are in a powdery form when visually observed. The above mild fiber CF is generally available from Sobue Clay Co., Ltd.

[0021] (Melt Kneading) As a method for uniformly mixing each component constituting the resin composition, a melt-kneading method can be preferably employed. In this kneading step, the above-mentioned components are kneaded using a kneader known in the art such as a tumbler, Henschel mixer, Banbury mixer, roll, Brabender, single-screw kneading extruder, twin-screw kneading extruder, kneader, etc., while appropriately adjusting conditions such as the kneading speed, kneading temperature, and kneading time.

[0022] For kneading, for example, after preliminarily mixing the above-mentioned components using a tumbler, Henschel mixer, etc., they may be melt-kneaded using a kneader such as a Banbury mixer, roll, Brabender, single-screw kneading extruder, twin-screw kneading extruder, kneader, etc. Also, for example, without preliminarily mixing the components, these components may be fed into an extruder using a feeder and melt-kneaded. Further, for example, only some of the components are preliminarily mixed, and then the resin composition obtained by melt-kneading is used as a masterbatch, and this masterbatch and the remaining components are melt-kneaded again.

[0023] The kneading temperature is determined based on the melting temperature (Tm) of the thermoplastic resin. As the measured value of Tm, similar to the glass transition point (Tg), any measured value such as DSC, TMA, DTA, a viscoelasticity apparatus with variable temperature can be used, but if kneading is carried out near the Tm temperature measured using these apparatuses, the resin composition of the present invention can be easily obtained.

[0024] As an example of the kneading conditions, in a twin-screw kneading extruder, raw materials are blended at a predetermined composition ratio (parts by mass), and as the kneader, a twin-screw melt-kneading extruder (manufactured by Technovel) with a screw diameter of 25 mm and a screw effective length L / D = 26 is used, and kneading is carried out at a cylinder temperature of 230°C to 240°C to obtain a resin composition.

[0025] Regarding the length of the carbon fiber (carbon fiber: CF), it is adjusted by changing the screw rotation speed (unit: rpm) under the above kneading conditions. As the reference screw rotation speed (unit: rpm), in this example, it is set to 250 rpm to 300 rpm. Also, in order to shorten the length of the carbon fiber, the screw rotation speed (unit: rpm) is changed by reducing it to about 50 rpm to 100 rpm, and set to 150 rpm to 250 rpm. Also, in the examples described below, using the obtained resin composition containing carbon fiber, it was melted at a set temperature of 240 to 260°C and injection molded to obtain evaluation pieces (test samples).

Examples

[0026] The present invention will be described in more detail based on the following examples, but the technical scope of the present invention is not limited to the following examples in any way. Also, in the following description, unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass".

[0027] [Examples 1-1 to Examples 1-4] As the thermoplastic resin, a PC / ABS resin (product number MB8700) manufactured by Mitsubishi Chemical Corporation was prepared. As CF, a material manufactured by Carbon Fiber Recycling Industry Co., Ltd., having a fiber length of 3 mm and a fiber thickness of 5 μm was prepared. A twin-screw kneading extruder was used as the kneader, and the feeder was set so that the total of CF and the thermoplastic resin was 100% by mass and the mass ratio of CF to the thermoplastic resin (CF / thermoplastic resin) was the ratio shown in Table 1.

[0028] The kneading temperature of the twin-screw kneading extruder was adjusted to 230°C to 240°C, and kneading was performed by adding the required amount of CF with the feeder. In this example, the screw rotation speed of the twin-screw kneading extruder was set to 250 rpm to 300 rpm. Table 1 shows the results of observing the length of CF after kneading with a microscope. Using the carbon fiber-containing thermoplastic resin composition obtained after kneading, test samples for measuring the flexural modulus were made, and the flexural modulus was measured. The results are shown in Table 1 and FIG. 3.

[0029] <Measurement of Flexural Modulus> The measurement of the flexural modulus was carried out in accordance with JIS K7171. The resin composition was molded into a size of 80×10×4 mm to prepare a measurement sample.

[0030]

Table 1

[0031] From the above results, it was confirmed that the fibers of CF became shorter due to kneading. As the addition amount of CF increased to 3%, 6%, 9%, and 12%, the value of the flexural modulus (Mpa) increased linearly. Thereby, a tendency was observed that the value of the flexural modulus (Mpa) increased proportionally depending on the addition amount of CF. However, when more than 12% of CF was added, entanglement of CF was observed, and in this example, it was found that the maximum should be 12%. Also, it was found that preferably it should be 9%. Also, when the fiber thickness was 1μm to 10μm, the same tendency as in Examples 1-1 to 1-4 was obtained.

[0032] [Examples 2-1 to 2-4] As the thermoplastic resin, PC / ABS resin (product number MB8700) manufactured by Mitsubishi Chemical Corporation was prepared. As CF, a material manufactured by Sobue Clay Co., Ltd., with a fiber length of 25μm to 50μm and a fiber thickness of 5μm was prepared. A twin-screw kneading extruder was used as the kneader, and the feeder was set so that the total of CF and the thermoplastic resin was 100% by mass and the mass ratio of CF to the thermoplastic resin (CF / thermoplastic resin) was the ratio shown in Table 2.

[0033] The kneading temperature of the twin-screw kneading extruder was adjusted to 230°C to 240°C, and kneading was carried out by adding the required amount of CF with the feeder. In this example, the screw rotation speed of the twin-screw kneading extruder was set to 250 to 300 rpm. Table 2 shows the results of observing the length of CF after kneading under a microscope. As a result, it was confirmed that the fibers of CF became shorter due to kneading. Using the thermoplastic resin composition containing carbon fiber obtained after kneading, test samples for measuring the flexural modulus were made and the flexural modulus was measured. The results are shown in Table 2 and Figure 4.

[0034]

Table 2

[0035] From the above results, as the addition amount of CF increased to 3%, 6%, 9%, and 12%, the value of the flexural modulus (Mpa) increased linearly. As a result, it was found that the value of the flexural modulus (Mpa) tended to increase proportionally with the addition amount of CF. However, when adding more than 12% of CF, aggregation of CF was observed, and it was found that in this example, the maximum should be 12%. Also, it was found that preferably it should be 9%. In addition, when the fiber thickness was set to 1μm to 10μm, the same tendency as in Examples 1-1 to 1-4 was obtained.

[0036] Regarding the test results of Examples 1-1 to 1-4 and Examples 2-1 to 2-4, since the flexural modulus improved linearly according to the fiber content ratio, it was found that for this material type, the flexural modulus can be adjusted to some extent depending on the fiber length. In addition, when the addition amount of CF was the same, it was found that the flexural modulus improved as the fiber length increased. As the thermoplastic resin, PC / ABS (product number MB8700) manufactured by Mitsubishi Chemical Corporation was used, and the flexural modulus of this material alone was 3000 (Mpa). Based on this value of the flexural modulus, when aiming to improve the flexural modulus, the addition amount of CF at which the flexural modulus is 4000 (Mpa) or more is effective.

[0037] [Examples 3-1 to 3-4] As the thermoplastic resin, PC / ABS resin (product number MB8700) manufactured by Mitsubishi Chemical Corporation was prepared. As the CF, a material manufactured by Carbon Fiber Recycling Industry Co., Ltd. with a fiber length of 3 mm and a fiber thickness of 5 μm was prepared. A twin-screw kneading extruder was used as the kneader, and the feeder was set so that the total of CF and the thermoplastic resin was 100% by mass and the mass ratio of CF to the thermoplastic resin (CF / thermoplastic resin) was the ratio shown in Table 3.

[0038] Using a twin-screw kneading extruder, the kneading temperature was adjusted to 230 to 240 °C, and kneading was performed by adding the required amount of CF with a feeder. In this example, the screw rotation speed is 300 rpm to 350 rpm. When the CF after kneading was observed with a microscope, before kneading, the length of the CF was 3 mm, but in the state after kneading, the length was about 50 μm to 150 μm on average. From this result, it was found that the length of CF can be controlled in the kneading process by changing the screw rotation speed (unit: rpm). Using the carbon fiber-containing thermoplastic resin obtained after kneading, a test sample for measuring the flexural modulus was prepared, and the flexural modulus was measured. The results are shown in Table 3.

[0039]

Table 3

[0040] As a result obtained from Examples 3-1 to 3-4, by increasing the addition amount of CF to 3, 6, 9, and 12%, the value of the flexural modulus (Mpa) improved linearly. Thereby, a tendency was observed that the value of the flexural modulus (Mpa) increased proportionally depending on the addition amount of CF. However, when more than 12% of CF was added, entanglement of CFs was observed, and in this example, it was found that the amount should be at most 12%. Also, it was found that it should preferably be 9%. Also, when the fiber thickness was 1 μm to 10 μm, the results were the same as those of the above Examples 1-1 to 1-4.

[0041] The relationships between the CF addition amounts and the flexural strengths in Example 1 (Examples 1-1 to 1-4), Example 2 (Examples 2-1 to 2-4), and Example 3 (Examples 3-1 to 3-4) are shown in Table 4 and Figure 5 below. Regarding the flexural modulus, evaluation was performed with 4000 Mpa or more being rated as ○.

[0042] Also, for comparison, the results of the flexural elasticity of PC / ABS (MB8700 virgin material) alone are shown in Figure 5 (shown as "Comparative Example"). Since PC / ABS (MB8700 virgin material) was 3000 Mpa, in terms of flexural strength, if it is 4000 Mpa or more, it can be considered to have high strength. Regarding the flexural modulus, evaluation was performed with 4000 Mpa or more being rated as ○.

[0043] (Molding shrinkage rate) Also, using the samples of Example 1-2, Example 2-2, and Example 3-2 where the CF addition amount was 6%, the molding shrinkage rate was evaluated. The results are shown in Table 4. The measurement method of the molding shrinkage rate of the thermoplastic resin added with CF will be explained. As a test method, measurement is performed in accordance with ASTM D955 (Standard Test Method for Measuring Shrinkage from Mold Dimensions of Thermoplastic Resins). For example, the molding shrinkage rate in the flow direction is calculated by the following formula (1). SFlow = 100×(LM - LS) / LM (1) In formula (1), LM and LS are as follows. LM: The length of the section of the mold cavity LS: The corresponding length of the test piece after cooling Measure how much the molded body shrinks after molding from the length of the test sample molded after cooling with respect to the length of the mold. The size of the mold is not particularly limited, but a size of 200 mm × 70 mm (t = 1.6) was used. A thermoplastic resin added with CF was used to produce a molded body by an injection molding method. Measure the dimensions in the MD (Machine Direction, flow direction) and TD (direction perpendicular to the flow direction in the Traverse Direction) of the resin injected into the injection molding die.

[0044] Here, the comparison of the molding shrinkage rate was carried out by comparing it with the molding shrinkage rate of a commercially available resin filled with filler as a comparison target. The resin filled with filler has inorganic materials such as talc, mica, and glass filler added to the thermoplastic resin. By adding the inorganic material, strength physical properties such as the flexural modulus are improved.

[0045] Hereinafter, a resin material filled with filler (product number: DN - 7730M) manufactured by Teijin Limited was used as a comparison target and compared with the carbon fiber - containing resin composition of the present invention. The measurement of the molding shrinkage rate was carried out according to ASTM D955 (Standard Test Method for Measuring Shrinkage from Mold Dimensions of Thermoplastic Resins) as a test method.

[0046] As a result, the molding shrinkage rate of the resin material filled with filler (product number: DN - 7730M) manufactured by Teijin Limited was as follows. MD: 0.2% TD: 0.3%

[0047] On the other hand, the same measurement of the molding shrinkage rate was carried out for the thermoplastic resin added with CF. If the following results are obtained, there will be few errors in the molding dimensions and a good molded body can be obtained. MD: 0.2% TD: 0.3%

[0048] The measurement results of the molding shrinkage rate for Examples 1-2, Example 2-2, and Example 3-2 with a CF addition amount of 6% are shown below.

[0049]

Table 4

[0050] Regarding the flexural modulus, values of 4000 Mpa or more were evaluated as ○. Regarding the molding shrinkage rate, cases where MD is 0.2% and TD is 0.3% were evaluated as ○. This is also effective for the standardization of molds during injection molding. On the other hand, when there is a difference in numerical values between the molding shrinkage rate MD (flow direction) and the molding shrinkage rate TD (direction perpendicular to the flow), anisotropy occurs due to factors such as the orientation of carbon fibers. In this case, it was marked as × because it causes a problem where the dimensions of the molded product manufactured by injection molding are different in the XY directions. From the viewpoints of the flexural modulus, the molding shrinkage rate MD (flow direction), and the molding shrinkage rate TD (direction perpendicular to the flow) of the sample with 6% CF added, Example 3-2 received ○ in all evaluations, improving the strength such as the flexural modulus and reducing the situation where the molding shrinkage rates are different in the resin flow direction (Y) and the direction perpendicular to the resin flow (X), so it is preferable.

[0051] As an effect of the average fiber length, if it is shorter than 50 μm, the strength such as the flexural strength does not increase, and if it is longer than 150 μm, anisotropy occurs, causing problems with the molding shrinkage rate and not meeting the required dimensions of the molded body. As an effect of the carbon fiber content, if it is less than 3%, the strength such as the flexural strength does not increase, and if it is more than 9%, anisotropy occurs, causing problems with the molding shrinkage rate and not meeting the required dimensions of the molded body, and causing problems such as entanglement and aggregation of carbon fibers.

[0052] Aspects of the present invention are as follows, for example. (1) A carbon fiber-containing resin composition obtained by kneading carbon fibers into a thermoplastic resin, The average length of the carbon fiber is 50 μm or more and 150 μm or less, the content of the carbon fiber with respect to the thermoplastic resin is 3% by mass or more and 9% by mass or less, the flexural strength of the carbon fiber-containing resin is 4000 Mpa or more, and the carbon fiber-containing resin composition is characterized by this. (Effect) Since the carbon fiber-containing resin composition has the above configuration, the anisotropy in the molding shrinkage rate can be eliminated, and the strength physical properties can be improved. Since the average length of the fiber is 50 μm or more and 150 μm or less, it has sufficient flexural strength, no anisotropy occurs, and there is no problem in the molding shrinkage rate, and the molded body becomes the required dimensions. (2) The carbon fiber-containing resin composition according to (1) above, wherein the thickness of the carbon fiber is 1 μm or more and 10 μm or less. (Effect) Since the thickness of the carbon fiber is 1 μm or more and 10 μm or less, sufficient strength is obtained, and there is no variation in quality during the kneading process. (3) The carbon fiber-containing resin composition according to (1) or (2) above, wherein the thermoplastic resin is a PC resin (polycarbonate resin), a PC resin (polycarbonate resin) / ABS resin (acrylonitrile-butadiene-styrene copolymer resin), or a mixture of a PC resin (polycarbonate resin) and a PC resin (polycarbonate resin) / ABS resin (acrylonitrile-butadiene-styrene copolymer resin). (Effect) Since the thermoplastic resin is the above material, the resin composition can maintain high strength characteristics and flame retardancy. (4) The carbon fiber-containing resin composition according to any one of (1) to (3) above, wherein the carbon fiber is a recycled material. (Effect) The recovery material loading rate can be improved. (5) The carbon fiber-containing resin composition according to any one of (1) to (4) above, wherein the thermoplastic resin is a recycled material. (Effect) The recovery material loading rate can be improved.

Prior Art Documents

Patent Documents

[0053]

Patent Document 1

Claims

1. A carbon fiber-containing resin composition obtained by kneading carbon fibers into a thermoplastic resin, wherein the average length of the carbon fibers is 50 μm or more and 150 μm or less, the content of the carbon fibers with respect to the thermoplastic resin is 3% by mass or more and 9% by mass or less, and the flexural strength of the carbon fiber-containing resin is 4000 MPa or more. A carbon fiber-containing resin composition characterized by the above.

2. The carbon fiber-containing resin composition according to claim 1, wherein the thickness of the carbon fibers is 1 μm or more and 10 μm or less.

3. The carbon fiber-containing resin composition according to claim 1 or 2, wherein the thermoplastic resin is a PC resin (polycarbonate resin), a PC resin (polycarbonate resin) / ABS resin (acrylonitrile-butadiene-styrene copolymer resin), or a mixture of a PC resin (polycarbonate resin) and a PC resin (polycarbonate resin) / ABS resin (acrylonitrile-butadiene-styrene copolymer resin).

4. The carbon fiber-containing resin composition according to claim 1 or 2, wherein the carbon fibers are recycled materials.

5. The carbon fiber-containing resin composition according to claim 1 or 2, wherein the thermoplastic resin is a recycled material.

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