Thermoplastic resin composition for recycled carbon fiber reinforced plastics, and recycled carbon fiber reinforced plastics

Abstract

To provide a resin composition for a recycled carbon fiber-reinforced plastic which enables formation of a recycled carbon fiber-reinforced plastic that is excellent in productivity even if recycled carbon fibers are used, and is excellent not only in tensile elastic modulus but also in impact resistance, and a recycled carbon fiber-reinforced plastic using the same.SOLUTION: A thermoplastic resin composition contains recycled carbon fibers (A) and at least two kinds of thermoplastic resins (B) having different elastic moduli, has a sea-island structure having a domain (D) and a matrix (M) specified by the elastic moduli, and satisfies (1) to (3). (1) An average value of a circular coefficient of the domain (D) determined by Expression [maximum diameter2 of domain (D)×π) / (4×area of domain (D))] is 1.0 to 2.5, (2) an average area of the domain (D) is 0.001 to 0.5 μm2, and (3) an area ratio D:M of the domain (D) to the matrix (M) is 1:99 to 50:50.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a thermoplastic resin composition for recycled carbon fiber reinforced plastics and a recycled carbon fiber reinforced plastic formed from the thermoplastic resin composition.

Background Art

[0002] Carbon fiber reinforced plastics (hereinafter sometimes referred to as CFRP) reinforced with carbon fiber (hereinafter sometimes referred to as CF) are widely used in industrial products such as sports goods and aircraft parts. The rotor blades of wind turbines that have hitherto used glass fiber composite materials are being replaced with lightweight and high-strength CFRP in order to achieve efficiency improvement and enlargement. [[ID=]13]

[0003] In addition, in parts of automobiles and aircraft where safety is emphasized, there are many end materials of intermediate products generated in the manufacturing process of CFRP. Furthermore, in addition to the expanding demand for CFRP, since the lifespan of CFRP for aircraft parts etc. is said to be about 20 years, it is expected that CFRP waste materials will continue to increase in the future. For this reason, recycled carbon fiber reinforced plastics (hereinafter sometimes referred to as r-CFRP) using recycled carbon fiber (hereinafter sometimes referred to as r-CF) recovered from CFRP waste materials etc. have been studied.

[0004] Hitherto, used CFRP waste materials and end materials (prepregs, sheet molding compounds, etc.) generated in the manufacturing process of CFRP have been crushed and then landfilled, but in order to reuse them as r-CF, a method for recovering r-CF has been studied.

[0005] For example, Patent Document 1 discloses a method for recovering r-CF, which involves crushing CFPR into flakes and then carbonizing it in a substantially non-oxidizing atmosphere at a temperature range of 300 to 1,000°C, and a method for carbonizing CFPR in a substantially non-oxidizing atmosphere at a temperature range of 300 to 1,000°C and then crushing it into flakes. Patent Document 2 discloses a method for obtaining r-CF from CFRP containing CF and matrix resin, which involves heating the CFRP to thermally decompose the matrix resin, obtaining a heat-treated product with a resin residue content of 0.01 to 30.0% by mass, and then cutting the heat-treated product.

[0006] Furthermore, as an example of r-CFRP using r-CF, Patent Document 3 discloses r-CFRP obtained using a resin and r-CF having a fiber length variation coefficient of 20% or more and not containing a sizing agent. Patent Document 4 also discloses r-CFRP containing r-CF, a polyolefin resin, and a dispersant having a basic group. In this r-CF, the average fiber length is 0.05 to 15.0 mm, and the amount of r-CF blended is 1 to 50% by mass in 100% by mass of r-CFRP. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 7-118440 [Patent Document 2] Japanese Patent Publication No. 2020-075493 [Patent Document 3] Japanese Patent Publication No. 2019-163354 [Patent Document 4] Japanese Patent Publication No. 2020-176244 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Furthermore, the strength required for reinforced plastics includes not only the tensile modulus, which represents the hardness of the material itself when force is applied slowly, but also impact resistance, which is the ability to disperse force when it is applied instantaneously. However, with recycled carbon fiber reinforced plastics, while it is possible to create a reinforced plastic with improved tensile modulus by kneading r-CF into the resin, r-CF has poor compatibility with resin, and even when attempting to knead it into the resin, the extrusion is unstable, resulting in poor productivity and problems with impact resistance. Currently, it is not possible to achieve both tensile modulus and impact resistance simultaneously.

[0009] Therefore, the present invention has been made in view of the above background, and aims to provide a resin composition for recycled carbon fiber reinforced plastics that is excellent in productivity even when recycled carbon fibers are used, and that can form recycled carbon fiber reinforced plastics that are excellent not only in tensile modulus but also in impact resistance, and recycled carbon fiber reinforced plastics using the same. [Means for solving the problem]

[0010] After diligent research by the inventors, we discovered that the problems of the present invention can be solved in the following embodiment, and thus completed the present invention. [1]: A thermoplastic resin composition for recycled carbon fiber reinforced plastics, It contains recycled carbon fiber (A) and at least two thermoplastic resins (B) with different elastic moduli. It exhibits a sea-island structure having domains (D) and matrices (M) specified by the elastic modulus, and is characterized by satisfying the following (1) to (3): Thermoplastic resin composition. (1) Maximum diameter (μm) and area (μm) of domain (D) 2 The average value of the circularity coefficient of domain (D), which can be obtained from the following formula (1), is between 1.0 and 2.5. (2) The average area of ​​domain (D) is 0.001 to 0.5 μm 2 That is the case. (3) The area ratio D:M between the domain (D) and the matrix (M) is 1:99 to 50:50. Circularity coefficient of domain (D) =(Maximum diameter of domain (D)) 2 ×π) / (4 × area of ​​domain (D))···Formula (1) [2]: The thermoplastic resin composition according to [1], characterized in that the average aspect ratio of domain (D) is 1.0 to 2.0. [3] Domain diameter D of domain (D) 90 Domain diameter D 10 A thermoplastic resin composition according to [1] or [2], characterized in that the value obtained by dividing by is 1.5 to 25. [4]: The thermoplastic resin (B) is a thermoplastic resin composition according to any one of [1] to [3], comprising an acid-modified thermoplastic elastomer. [5]: A recycled carbon fiber reinforced plastic formed from any of the thermoplastic resin compositions described in [1] to [4]. [6]: Contains recycled carbon fiber (A) and at least two thermoplastic resins (B) with different moduli, A recycled carbon fiber reinforced plastic characterized by having a sea-island structure with domains (D) and a matrix (M) specified by the elastic modulus, and satisfying the following conditions (1) to (3). (1) Maximum diameter (μm) and area (μm) of domain (D) 2 The average value of the circularity coefficient of domain (D), which can be obtained from the following formula (1), is between 1.0 and 2.5. (2) The average area of ​​domain (D) is 0.001 to 0.5 μm 2 That is the case. (3) The area ratio D:M between the domain (D) and the matrix (M) is 1:99 to 50:50. Circularity coefficient of domain (D) =(Maximum diameter of domain (D)) 2 ×π) / (4 × area of ​​domain (D))···Formula (1) [7]: Recycled carbon fiber (A) and recycled carbon fiber (A) and at least two thermoplastic resins (B) with different moduli are melt-mixed together. A thermoplastic resin composition having a sea-island structure characterized by a domain (D) and a matrix (M) specified by an elastic modulus and satisfying the following (1) to (3). A method for producing a thermoplastic resin composition for reinforcing recycled carbon fibers. (1) The average value of the circularity coefficient of the domain (D) obtained by the following formula (1) from the maximum diameter (μm) and the area (μm 2 ) of the domain (D) is 1.0 to 2.5. (2) The average area of the domain (D) is 0.001 to 0.5 μm 2 . (3) The area ratio D:M of the domain (D) and the matrix (M) is 1:99 to 50:50. Circularity coefficient of the domain (D) =(Maximum diameter of the domain (D)2×π) / (4×Area of the domain (D)) ··· Formula (1) [Advantages of the Invention]

[0011] According to the present invention, even when using recycled carbon fibers, a thermoplastic resin composition for recycled carbon fiber reinforced plastics excellent in productivity can be formed, and the recycled carbon fiber reinforced plastics obtained thereby can be excellent in tensile elastic modulus and impact resistance. [Brief Description of the Drawings]

[0012] [Figure 1] Examples of elastic modulus images of SPM measurements of cross-sections of r-CFRP in Examples and Comparative Examples. [Figure 2] Elastic modulus image of SPM measurement of cross-section of r-CFRP in Example 8. [Figure 3] Analytical image obtained by binarizing the elastic modulus image of SPM measurement of cross-section of r-CFRP in Example 8 with image processing software. [Figure 4] Examples of the maximum object width and minimum object width of the domain (D) in Example 8. [Modes for Carrying Out the Invention]

[0013] Examples of thermoplastic resin compositions and recycled carbon fiber reinforced plastics of this disclosure are described below. Furthermore, other embodiments are also included in the scope of the present invention, insofar as they are consistent with the spirit of the present invention. In addition, numerical ranges specified using "~" in this specification include the numerical values ​​before and after "~". In this specification, recycled carbon fiber is referred to as r-CF, and carbon fiber (i.e., non-recycled carbon fiber) as CF. Furthermore, recycled carbon fiber reinforced plastic is referred to as r-CFRP, and carbon fiber reinforced plastic (i.e., non-recycled carbon fiber reinforced plastic) as CFRP. Furthermore, "non-recycled carbon fiber reinforced plastics and / or recycled carbon fiber reinforced plastics" are sometimes referred to as "reinforced plastics." Furthermore, unless otherwise noted, each of the components mentioned herein may be used independently, individually, or in combination of two or more. The numerical values ​​specified herein are those obtained by the methods disclosed in the embodiments or examples.

[0014] 《Thermoplastic resin composition》 The thermoplastic resin composition of the present invention is used to form recycled carbon fiber reinforced plastics and contains recycled carbon fiber (A) (hereinafter also referred to as r-CF(A)) and at least two thermoplastic resins (B) with different elastic moduli. As a result of diligent research by the inventors, it was found that by exhibiting a sea-island structure having domains (D) and a matrix (M) specified by the elastic modulus, and satisfying the following conditions (1) to (3), the compatibility between the thermoplastic resin and recycled carbon fiber is significantly improved, the thermoplastic resin composition has excellent productivity, and furthermore, the obtained recycled carbon fiber reinforced plastic can have improved tensile modulus and impact resistance. As a result, it is possible to reinforce recycled carbon fiber to the same extent as when non-recycled carbon fiber is used, and it is expected that parts that have previously used metal materials can be replaced with r-CFRP, which has superior lightweight properties. (1) Maximum diameter (μm) and area (μm) of domain (D) 2The average value of the circularity coefficient of domain (D), which can be obtained from the following formula (1), is between 1.0 and 2.5. (2) The average area of ​​domain (D) is 0.001 to 0.5 μm 2 That is the case. (3) The area ratio D:M between the domain (D) and the matrix (M) is 1:99 to 50:50. Circularity coefficient of domain (D) =(Maximum diameter of domain (D)) 2 ×π) / (4 × area of ​​domain (D))···Formula (1)

[0015] <Domain (D) and Matrix (M)> The thermoplastic resin composition and recycled carbon fiber reinforced plastic have a sea-island structure with domains (D) and a matrix (M). The sea-island structure in a thermoplastic resin composition is formed by using multiple thermoplastic resins and can be controlled by the properties of the materials used, such as the compatibility and elastic modulus of the thermoplastic resins, as well as the mixing conditions of the resin composition. The sea-island structure of the present invention is formed from at least two thermoplastic resins with different elastic moduli. Preferably, the domain (D) is formed from a thermoplastic resin with a low elastic modulus, and the matrix (M) is formed from a thermoplastic resin with a high elastic modulus. As a result, at least two types of thermoplastic resins are clearly separated into domains (D) and matrix (M) derived from the thermoplastic resin, depending on the difference in elastic modulus, and a sea-island structure is observed. The sea-island structure is identified by observing the cross-sections of resin compositions and recycled carbon fiber reinforced plastics with a scanning probe microscope (hereinafter abbreviated as SPM) and detecting differences in elastic modulus. An SPM is a microscope that observes the surface condition by scanning the sample surface while tapping it with a tiny probe (cantilever). In addition to general surface shapes such as irregularities, the peak voltage value generated during tapping corresponds to the elastic modulus of the measured surface, so the magnitude of the elastic modulus of the surface can be represented as an image by this voltage peak value. Specifically, cross-sections of resin compositions and recycled carbon fiber reinforced plastics are observed using an Oxford Instruments MFP-3D with a cantilever: AC-160TS, in dynamic measurement mode. The measurement range is 5 μm × 5 μm, and the elastic modulus image is observed. Methods for obtaining cross-sections for observation with SPM include freezing the sample with liquid nitrogen and then fracturing it (freeze fracturing method), cutting the sample with a sharp blade such as a razor (microtome method), smoothing the cross-section of the sample cut with a cutter using abrasive paper, and processing the sample by irradiating it with an ion beam using a cross-section polisher device (ion milling method). While various methods can be used to obtain cross-sections, the ion milling method is the most preferred among them. The sea-island structure, which has domains (D) and a matrix (M), does not change significantly depending on the flow direction during molding of the thermoplastic resin composition; the morphology of the sea-island structure is the same regardless of the direction in which the resin composition and recycled carbon fiber reinforced plastic are cut.

[0016] "Circularity coefficient of domain (D)" Maximum diameter (μm) and area (μm) of domain (D) 2 The average value of the circularity coefficient of domain (D), which can be obtained from the following formula (1), is between 1.0 and 2.5. The circularity coefficient of domain (D) = (the maximum diameter of domain (D)) 2 ×π) / (4 × area of ​​domain (D)) ···Formula (1) Here, the maximum diameter is the maximum length of the selected domain (D). For example, taking one domain (D) in Example 8 as an example, this refers to the maximum object width (μm) in Figure 4.

[0017] The circularity coefficient is an indicator of how close a domain (D) is to a circle, and it indicates whether the shape of the domain (D) is close to a circle (the smaller the value, the closer it is to a circle). An average value of 1.0 to 2.5 for the circularity coefficient improves the tensile modulus and impact resistance. A circularity coefficient of 1.1 to 2.0 is preferable, and 1.1 to 1.5 is more preferable. If the circularity coefficient is greater than 2.5, the force received from an impact cannot be dispersed, resulting in reduced impact resistance.

[0018] "Average area of ​​domain (D)" The average area of ​​domain (D) is 0.001 to 0.5 μm². 2 It is 0.003~0.3μm 2 It is more preferable that it be 0.001 μm 2 If the particle size is smaller, the thermoplastic resin becomes excessively dispersed, impairing its cushioning properties upon impact and reducing its impact resistance. (0.5 μm) 2 If the value is greater than this, poor dispersion leads to poor compatibility between the thermoplastic resin and r-CF, resulting in reduced impact resistance and tensile modulus. The average area of ​​the domain (D) is obtained by binarizing the elastic modulus image obtained by the above SPM using the free software "ImageJ" and calculating the number of pixels for each color in the domain (D) and matrix (M).

[0019] "Area ratio between domain (D) and matrix (M)" In the present invention, the ratio of domains (D) to matrix (M) in the sea-island structure is domain (D) ≤ matrix (M). Furthermore, the area ratio (D):(M) of domains (D):(M) is 1:99 to 50:50. From the viewpoint of tensile modulus, 5:95 to 40:60 is preferred, and 5:95 to 30:70 is more preferred. When the proportion of domains (D) exceeds that of matrix (M), the tensile modulus decreases significantly. The area ratio (D):(M) is obtained by binarizing the elastic modulus image obtained by SPM using the free software "ImageJ" and calculating the number of pixels for each color in the domain (D) and matrix (M). The ratio of domain (D) increases as the proportion of thermoplastic resin with a low elastic modulus increases.

[0020] "Average aspect ratio of the domain (D)" The average aspect ratio of domain (D), calculated from the number-average value (μm) of the maximum object width (μm) and the number-average value (μm) of the minimum object width (μm) of domain (D), is preferably 1.0 to 2.0. It is more preferably 1.0 to 1.8, and even more preferably 1.0 to 1.5. Average aspect ratio = Average length of major axis ÷ Average length of minor axis ... Formula (2) Impact resistance is further improved when the average aspect ratio is 2.0 or less. The circularity coefficient and aspect ratio can be determined by binarizing the elastic modulus image obtained by SPM using the free analysis software "ImageJ" and then measuring the result.

[0021] "Domain diameter" In this invention, the domain diameter is determined by binarizing the elastic modulus image obtained by SPM of the cross-section of the resin composition or recycled carbon fiber reinforced plastic using the free analysis software "ImageJ," calculating the equivalent diameter of a circle from the area of ​​the domain (D), and determining the particle diameter values ​​at which the cumulative volume is 10%, 50%, and 90%, respectively, as the domain diameter D. 10 , D 50 and D 90 This is the result. The equivalent diameter of the circle is the diameter of an equivalent circle with the same area as the area of ​​domain (D), and can be calculated using the following formula. Equivalent diameter of a circle = 2√(Area / π) Domain diameter D 10 The domain diameter D is preferably 0.005 to 0.04 μm, and more preferably 0.01 to 0.03 μm. 50 The domain diameter D is preferably 0.01 to 0.1 μm, and more preferably 0.02 to 0.08 μm. 90The domain size is preferably 0.05 to 1.0 μm, and more preferably 0.1 to 0.5 μm. Being within this range is effective in improving impact resistance. Methods for adjusting the domain size include adjusting the degree of mixing when manufacturing the resin composition.

[0022] "D 90 / D 10 " Domain diameter D 90 Domain diameter D 10 The value obtained by dividing by (hereinafter, D 90 / D 10 (Also abbreviated) is preferably 1.5 to 25. More preferably 2 to 15, and even more preferably 5 to 10. By setting the various domain diameters within the above range, a resin composition with a mixture of large and small domains (D) is formed, which is preferable because it can further improve impact resistance compared to the case where the domain diameters are uniform. 90 / D 10 If it is less than 1.5, the domain diameter will be uniform, which is unsuitable for dispersing the impact received. If the compatibility between the resin forming the domains and the resin forming the matrix is ​​poor, D 90 / D 10 It is larger than 25, resulting in poor productivity and impact resistance.

[0023] <Recycled carbon fiber (A)> r-CF (recycled carbon fiber) is carbon fiber recovered by recycling scraps of CFRP (carbon fiber reinforced plastic) or CFRP waste. The CFRP used as raw material for r-CF includes CF (carbon fiber) and matrix resin, and includes not only molded products but also intermediate products before molding (prepreg, towpreg, sheet molding compound, stampable sheet, bulk molding compound, etc.). The shape of the CFRP and the form of the CF it contains are not particularly limited. Thermosetting resins, thermoplastic resins, etc., are used as the matrix resin of CFRP.

[0024] From the viewpoint of maintaining good strength in thermoplastic resin compositions containing r-CF(A), it is preferable that the lower limit of the carbon content of r-CF(A) is 80% by mass or more. It is preferable that the carbon content of r-CF(A) is 95.0% by mass or less. In addition, other elements such as nitrogen, silicon, sodium, and sulfur may be included in r-CF(A) within a range that does not affect the effects of the present invention.

[0025] The fiber length of r-CF(A) is preferably 0.05 mm or more from the viewpoint of further improving tensile modulus and impact resistance. There is no particular upper limit, but considering availability, 20 mm or less is preferable.

[0026] Examples of commercially available r-CF(A) include the CARBISO MF series (average fiber length 0.08~0.1 mm) and the CARBISO C series (average fiber length 3~10 mm). The average fiber length can be determined by the following method. For example, recycled carbon fibers can be observed using a scanning electron microscope (JEOL JSM-6700M) at an acceleration voltage of 5kV, and an image with 50,000x magnification (1024 x 1280 pixels) can be captured. Then, the long axis length of 20 arbitrary recycled carbon fibers can be measured from the captured image, and the average fiber length can be determined.

[0027] From the perspective of further increasing the productivity of thermoplastic resin compositions, the bulk density of r-CF(A) should be 0.03 to 1.0 g / cm³. 3 It is preferable that the bulk density of r-CF(A) be within this range. By using r-CF(A) with a bulk density within this range, it is possible to effectively suppress the accumulation of fibers at the supply port when supplying r-CF(A) to the production equipment during the manufacture of thermoplastic resin compositions, thereby increasing productivity. A more preferable range for the bulk density of r-CF(A) is 0.05 to 1.0 g / cm³. 3 A more preferable range is 0.1 to 1.0 g / cm³. 3 By adjusting the rotation speed of the crusher blades and the mesh opening of the classification mesh, a bulk density of 0.05 to 1.0 g / cm³ can be achieved. 3 r-CF(A) can be obtained. The bulk density can be calculated using a Scott volume meter (manufactured by Tsutsui Rikagakuki Co., Ltd.) as the measuring device. Recycled carbon fiber is poured into a straight cylindrical container from the top of the measuring device, and the mass of a certain volume of sample, leveled off when the container is full, is measured. The bulk density can then be calculated from the ratio of this mass to the container volume based on the following formula (3). Bulk density (g / mL) = (Mass of recycled carbon fiber in a leveled, fixed volume (g)) ÷ (Container volume (mL)) ... Formula (3)

[0028] From the viewpoint of achieving both impact resistance and productivity, the amount of r-CF(A) blended is preferably 10 to 50% by mass, more preferably 15 to 40% by mass, and even more preferably 20 to 40% by mass, of 100% by mass of the thermoplastic resin composition.

[0029] <Thermoplastic resin (B)> Thermoplastic resins are resins that soften and become plastic when heated to a suitable temperature, and solidify when cooled. The thermoplastic resin composition of the present invention comprises at least two thermoplastic resins (B) having different elastic moduli. The thermoplastic resin (B) is not particularly limited, and various selections are possible as long as the resin portion of the thermoplastic resin composition exhibits a sea-island structure having domains (D) and a matrix (M) specified by the elastic modulus, and satisfies (1) to (3). In this invention, the modulus of elasticity refers to the tensile modulus of elasticity measured in accordance with JIS K7161.

[0030] As for the thermoplastic resin (B), various selections are possible as long as there are at least two thermoplastic resins with different elastic moduli, but the elastic moduli (E) of the thermoplastic resin constituting the matrix (M) are important. M ) and the elastic modulus (E) of the thermoplastic resin constituting domain (D). D )but, Modulus of elasticity (E M )> Elastic modulus (E D ) It is preferable that the relationship is satisfied. The elastic modulus (E) of the thermoplastic resin constituting the matrix (M) MThe value of (E) is preferably 1000 MPa to 8000 MPa from the viewpoint of impact resistance, and more preferably 1000 MPa to 5000 MPa from the ease of orientation of recycled carbon fibers. Also, the elastic modulus (E) of the thermoplastic resin constituting domain (D) D The value of ) is preferably in the range of 1 to 1500 MPa, and more preferably in the range of 1 to 1000 MPa. Furthermore, the modulus of elasticity (E M ) and elastic modulus (E D ) difference (elastic modulus (E M )-elastic modulus (E D It is preferable that the pressure is 500 MPa or higher, and more preferably 1000 MPa or higher. When the thermoplastic resin composition contains three or more types of thermoplastic resins, it is preferable that the elastic modulus of each mixture of the thermoplastic resin constituting the matrix (M) and the thermoplastic resin constituting the domain (D) satisfies the above requirements.

[0031] Examples of thermoplastic resins that can be used include polyamide resins, acrylic resins, polystyrene resins (PS), styrene resins such as acrylonitrile-butadiene-styrene copolymer resin (ABS), polyester resins, polycarbonate resins, polyethylene resins (PE), polyolefin resins such as polypropylene resin (PP), polyphenylene ether resins (PPE), polyacetal resins, polyester resins, polyvinyl chloride resins, and polyetherimide resins. These thermoplastic resins may also be acid-modified resins that have been modified with an acid or the like. Furthermore, these thermoplastic resins (B) may be thermoplastic elastomers, and may also be acid-modified thermoplastic elastomers that have been modified with an acid or the like.

[0032] In particular, it is preferable that the material be at least one of the following selected from the group consisting of polyamide resins (hereinafter also called thermoplastic resin (B1)), acrylic resins (hereinafter also called thermoplastic resin (B2)), styrene resins (hereinafter also called thermoplastic resin (B3)), polyester resins (hereinafter also called thermoplastic resin (B4)), polycarbonate resins (hereinafter also called thermoplastic resin (B5)), and polyolefin resins (hereinafter also called thermoplastic resin (B6)). From the viewpoint of balancing cost and mechanical properties, it is preferable that the material be thermoplastic resin (B1) or thermoplastic resin (B4). However, this excludes thermoplastic resins (B1), (B2), (B3), (B4), (B5), and (B6) when they are thermoplastic elastomers.

[0033] It is preferable to use these thermoplastic resins (B1), (B2), (B3), (B4), (B5), or (B6) in combination with a thermoplastic elastomer (hereinafter also referred to as thermoplastic resin (b)) from the viewpoint of compatibility between recycled carbon fiber (A) and thermoplastic resin (B). Furthermore, the thermoplastic resin (b) is preferably an acid-modified thermoplastic elastomer (hereinafter also referred to as thermoplastic resin (bx)).

[0034] Furthermore, when using thermoplastic resin (B6), it is preferable to use a combination of an acid-unmodified polyolefin resin and an acid-modified polyolefin resin.

[0035] Specifically, preferred combinations of thermoplastic resins (B) include, for example, thermoplastic resin (B1) and thermoplastic resin (b), thermoplastic resin (B2) and thermoplastic resin (b), thermoplastic resin (B3) and thermoplastic resin (b), thermoplastic resin (B4) and thermoplastic resin (b), thermoplastic resin (B5) and thermoplastic resin (b), or thermoplastic resin (B6) and thermoplastic resin (b), and more preferably, thermoplastic resin (b) is thermoplastic resin (bx). Furthermore, from the viewpoint of ease of handling and cost as a reinforced plastic, it is preferable to include a thermoplastic resin (B1) and a thermoplastic resin (bx), or a thermoplastic resin (B6) that is not acid-modified and an acid-modified polyolefin resin, and a thermoplastic resin (B6x).

[0036] From the viewpoint of the fluidity of the mixture, the content of thermoplastic resin (B) is preferably 50 to 100% by mass, more preferably 52 to 95% by mass, and even more preferably 60 to 90% by mass, of 100% by mass of the thermoplastic resin composition. Note that the above content is the total content of at least two types of thermoplastic resins.

[0037] Furthermore, when using an acid-modified polyolefin resin, the content of the acid-modified polyolefin resin is preferably 1 to 40% by mass, more preferably 1 to 30% by mass, and even more preferably 5 to 20% by mass, based on 100% by mass of the total thermoplastic resin (B). When the content of acid-modified polyolefin resin is within this range, the interfacial adhesion between r-CF(A) and thermoplastic resin(B) can be improved, and the generation of deposits at the die tip can be further suppressed, thereby improving productivity.

[0038] When a thermoplastic elastomer is included, the content of the thermoplastic elastomer is preferably 3 to 30% by mass, more preferably 5 to 25% by mass, and even more preferably 7 to 20% by mass, based on 100% by mass of the total thermoplastic resin (B). In particular, when an acid-modified thermoplastic elastomer is included, the content of the acid-modified thermoplastic elastomer is preferably 3 to 25% by mass, more preferably 5 to 20% by mass, and even more preferably 7 to 15% by mass, based on 100% by mass of the total thermoplastic resin (B).

[0039] When acid-modified polyolefin resin and thermoplastic elastomer are included, the total content of the acid-modified polyolefin resin and thermoplastic elastomer is preferably 3 to 30% by mass, more preferably 5 to 25% by mass, and even more preferably 7 to 20% by mass, based on 100% by mass of the total thermoplastic resin (B), in order to achieve high physical properties.

[0040] The thermoplastic resin (B) is preferably a thermoplastic resin with an average MFR of 10 g / min or more, and more preferably 20 g / min or more. An average MFR of 10 g / min or more for thermoplastic resin (B) reduces the melt viscosity when r-CF(A) and thermoplastic resin (B) are kneaded, suppressing the fracture of r-CF(A) and thus enabling the development of high mechanical properties. While there is no particular upper limit to the average MFR of thermoplastic resin (B), from the viewpoint of availability, it is usually 200 g / min or less.

[0041] The MFR of resin can be measured and determined in accordance with JIS K7210-1.

[0042] [Thermoplastic resin (B1): Polyamide resin (PA resin)] A polyamide resin (PA resin) can be used as the thermoplastic resin (B1). However, this excludes cases where the thermoplastic resin (B1) is a thermoplastic elastomer. Specific examples of thermoplastic resin (B1) include -[NH(CH2)5CO]-, -[NH(CH2)6NHCO(CH2)4CO]-, -[NH(CH2)6NHCO(CH2)8CO]-, and -[NH(CH2) 10 CO]-,-[NH(CH2)] 11A polyamide resin having at least one structural unit selected from the group consisting of CO]- and -[NH(CH2)2NHCO-D-CO]- (where D represents an unsaturated hydrocarbon with 3 to 4 carbon atoms) is preferably used. Specific examples include 6-nylon, 66-nylon, 610-nylon, 11-nylon, 12-nylon, 6 / 66 copolymer nylon, 6 / 610 copolymer nylon, 6 / 11 copolymer nylon, 6 / 12 copolymer nylon, 6 / 66 / 11 copolymer nylon, 6 / 66 / 12 copolymer nylon, 6 / 66 / 11 / 12 copolymer nylon, 6 / 66 / 610 / 11 / 12 copolymer nylon, and dimer acid-based polyamide resins.

[0043] Specific examples of the aforementioned 6-nylon resin include Amiran CM1041-LO (manufactured by Toray Industries, MFR: 21g / 10 min), Amiran CM1007 (manufactured by Toray Industries, MFR: 21g / 10 min), and Unitika Nylon A1020LP (manufactured by Unitika, MFR: 109g / 10 min).

[0044] Specific examples of the aforementioned 66-nylon resin include Amiran CM3001N (manufactured by Toray Industries, MFR: 103g / 10 min).

[0045] [Thermoplastic resin (B2): Acrylic resin] Acrylic resins can be used as the thermoplastic resin (B2). However, this excludes cases where the thermoplastic resin (B2) is a thermoplastic elastomer. Thermoplastic resin (B2) can be obtained by polymerizing (meth)acrylic monomers. Examples of monomers include (meth)acrylic monomers having alkyl groups, (meth)acrylic monomers having hydroxyl groups, (meth)acrylic monomers having carboxyl groups, (meth)acrylic monomers having glycidyl groups, and acrylic monomers having vinyl ester groups such as vinyl acetate and vinyl propionate. Among these, polymethyl methacrylate (PMMA) resin, which is a polymer of methyl methacrylate, is preferred because it can achieve a high modulus of elasticity. The thermoplastic resin (B2) is preferably an acrylic resin with a glass transition temperature of 0°C or higher.

[0046] Specific examples of acrylic resins (B2) include Acrypet TF-9 (manufactured by Mitsubishi Chemical Corporation, MFR 20g / 10 min).

[0047] [Thermoplastic resin (B3): Styrene-based resin] A styrene-based resin can be used as the thermoplastic resin (B3). However, this excludes cases where the thermoplastic resin (B3) is a thermoplastic elastomer. Thermoplastic resins (B3) are resins that use styrene monomers as monomers. Examples include styrene-based resins obtained by copolymerizing styrene monomer homopolymers, as well as other vinyl monomers or rubbery polymers that can copolymerize with them, as needed. The thermoplastic resin (B3) is preferably a styrene-based resin with a glass transition temperature of 0°C or higher.

[0048] Examples of styrene monomers include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, methoxystyrene, monobromstyrene, dibromstyrene, fluorostyrene, and tribromstyrene, among which styrene is particularly preferred from the viewpoint of excellent moldability.

[0049] Other vinyl monomers copolymerizable with styrene monomers include vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, aryl esters of acrylic acid such as phenyl acrylate and benzyl acrylate, alkyl esters of acrylic acid such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, cyclohexyl acrylate, and dodecyl acrylate, aryl methacrylates such as phenyl methacrylate and benzyl methacrylate, and methyl methacrylate. Examples include alkyl methacrylates such as methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, cyclohexyl methacrylate, and dodecyl methacrylate; epoxy group-containing methacrylates such as glycidyl methacrylate; maleimide monomers such as maleimide, N-methyl maleimide, and N-phenyl maleimide; and α,β-unsaturated carboxylic acids and their anhydrides, such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, phthalic acid, and itaconic acid.

[0050] Examples of rubbery polymers copolymerizable with styrene monomers include polybutadiene, polyisoprene, random and block copolymers of styrene-butadiene, acrylonitrile-butadiene copolymers, copolymers of alkyl acrylate or alkyl methacrylate and butadiene, diene copolymers such as butadiene-isoprene copolymers, copolymers of ethylene and α-olefins such as ethylene-propylene random and block copolymers, random and block copolymers of ethylene-butene, copolymers of ethylene and unsaturated carboxylic acid esters such as ethylene-methyl methacrylate copolymers and ethylene-butyl acrylate copolymers, copolymers of ethylene and aliphatic vinyls such as ethylene-vinyl acetate copolymers, non-conjugated dienate polymers of ethylene and propylene such as ethylene-propylene-hexadiene copolymers, acrylic rubbers such as butyl polyacrylate, and composite rubbers having a structure in which the polyorganosiloxane rubber component and the polyalkyl (meth)acrylate rubber component are intertwined with each other so that they cannot be separated.

[0051] Examples of styrene-based resins composed of these monomers include polystyrene, styrene-butadiene-styrene copolymer (SBS), high-impact polystyrene (HIPS), acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), methyl methacrylate-butadiene-styrene copolymer (MBS resin), methyl methacrylate-acrylonitrile-butadiene-styrene copolymer (MABS resin), acrylonitrile-acrylic rubber-styrene copolymer (AAS resin), acrylonitrile-ethylene propylene-rubber-styrene copolymer (AES resin), and styrene-IPN type rubber copolymer, or mixtures thereof.

[0052] Furthermore, as rubbery polymers copolymerizable with styrene monomers, polymers consisting of polybutadiene or polyisoprene, in which the unsaturated bonds are hydrogenated, can also be mentioned. Specific examples of such polymers include hydrogenated styrene-butadiene-styrene copolymer (hydrogenated SBS) and hydrogenated styrene-isoprene-styrene copolymer (SEPS). Among these, acrylonitrile-styrene copolymer (AS resin) or acrylonitrile-butadiene-styrene copolymer (ABS resin) is preferred due to its good compatibility with r-CF(A), and acrylonitrile-butadiene-styrene copolymer (ABS resin) is even more preferred due to its good impact resistance.

[0053] Specific examples of ABS resin include the Sebian T-500SF (manufactured by Daicel Mirise, MFR 25g / 10 min).

[0054] [Thermoplastic resin (B4): Polyester resin] Polyester resins can be used as the thermoplastic resin (B4). However, this excludes cases where the thermoplastic resin (B4) is a thermoplastic elastomer. Examples of thermoplastic resins (B4) include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexylenedimethylene terephthalate (PCT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), and liquid crystal polyester. A suitable thermoplastic resin (B4) is, for example, a thermoplastic resin composed of a saturated dicarboxylic acid and a saturated dihydric alcohol. As saturated dicarboxylic acids, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalene-1,4- or 2,6-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenyl dicarboxylic acids, and diphenoxyethanediethanedicarboxylic acids can be used, as well as aliphatic dicarboxylic acids such as adipic acid, sebatic acid, azelaic acid, and decane-1,10-dicarboxylic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid.

[0055] As saturated dihydric alcohols, aliphatic glycols such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, hexamethylene glycol, dodecamethylene glycol, neopentyl glycol, alicyclic glycols such as cyclohexanedimethanol, 2,2-bis(4'-β-hydroxyethoxyphenyl)propane, and other aromatic diols can be used.

[0056] Specific examples of polyester resins include Trecon 1401×06 (PBT resin, manufactured by Toray Industries, Ltd., MFR 25g / 10 min).

[0057] [Thermoplastic resin (B5): Polycarbonate resin (PC resin)] Polycarbonate resin (PC resin) can be used as the thermoplastic resin (B5). However, this excludes cases where the thermoplastic resin (B5) is a thermoplastic elastomer. As the thermoplastic resin (B5), for example, a resin that can be easily produced by reacting an aromatic dihydroxy compound with a carbonate precursor such as phosgene or diester carbonate can be used. The resin can be produced by known reactions, for example, by an interfacial method when using phosgene, or by a transesterification method in which the reaction is carried out in a molten state when using diester carbonate.

[0058] Examples of aromatic dihydroxy compounds include bis(hydroxyaryl)alkanes such as 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxy-3-t-butylphenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, and 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, as well as 1,1-bis(4-hydroxy(hydroxy) Examples include bis(hydroxyaryl)cycloalkanes such as phenyl)cyclopentane and 1,1-bis(4-hydroxyphenyl)cyclohexane, dihydroxydiaryl ethers such as 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, dihydroxydiaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide, and dihydroxydiaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone. In addition to these, piperazine, dipiperidyl hydroquinone, resorcinol, and 4,4'-dihydroxydiphenyl compounds may be used in combination. Furthermore, branched aromatic polycarbonate resins containing polyfunctional compounds such as phloroglucin can also be used.

[0059] Examples of carbonate precursors to be reacted with aromatic dihydroxy compounds include phosgene, diaryl carbonates such as diphenyl carbonate and ditril carbonate, and dialkyl carbonates such as dimethyl carbonate and diethyl carbonate.

[0060] Specific examples of PC resin include Yupiron E-2000 (manufactured by Mitsubishi Engineering Plastics Corporation, MFR 5g / 10 min), etc.

[0061] [Thermoplastic resin (B6): Polyolefin resin] Polyolefin resin can be used as the thermoplastic resin (B6). However, this excludes cases where the thermoplastic resin (B6) is a thermoplastic elastomer. Examples of thermoplastic resins (B6) include homopolymers of α-olefins having approximately 2 to 8 carbon atoms, such as ethylene, propylene, and 1-butene, and (co)polymers of these α-olefins with other α-olefins having approximately 2 to 18 carbon atoms, such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-hexene, 4-methyl-1-hexene, 1-heptene, 1-octene, 1-decene, and 1-octadecene.

[0062] Specifically, examples include ethylene homopolymers such as linear low-density polyethylene resin (LLDPE), low-density polyethylene resin (LDPE), and high-density polyethylene resin (HDPE); ethylene copolymers such as ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-propylene-1-butene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-1-heptene copolymer, and ethylene-1-octene copolymer; and propylene copolymers such as propylene homopolymer (homoPP), propylene-ethylene block copolymer (blockPP), propylene-ethylene random copolymer (randomPP), propylene-ethylene-1-butene copolymer, propylene-ethylene-4-methyl-1-pentene copolymer, and propylene-ethylene-1-hexene copolymer. These polyolefin resins may be used individually or in combination of two or more types. Propylene resins are preferred because they can achieve high mechanical properties, and among them, propylene homopolymers (homoPP) are even more preferred because they can increase the load deflection temperature.

[0063] Specific examples of polyolefin resins include Prime PolyPro J229E (manufactured by Prime Polymer, random PP, MFR 50g / 10min), Prime PolyPro J708UG (block PP, MFR 45g / 10min), and Sun Allomer PM900A (manufactured by Sun Allomer, homo PP, MFR 30g / 10min).

[0064] "Thermoplastic resin (B6x)" Acid-modified polyolefin resin can be used as the thermoplastic resin (B6x). However, this excludes cases where the thermoplastic resin (B6x) is a thermoplastic elastomer. Using thermoplastic resin (B6x) is preferable because it improves the compatibility between r-CF(A) and thermoplastic resin (B), thereby increasing adhesion. Furthermore, since high mechanical properties can be achieved, it is even more preferable that the thermoplastic resin (B6x) is an acid-modified propylene resin. In particular, using a combination of un-acid-modified polyolefin resin and acid-modified polyolefin resin is preferable from the viewpoint of ease of handling and cost as a reinforced plastic. It is also preferable because it significantly improves compatibility and allows for the production of thermoplastic resin compositions with high impact resistance.

[0065] Acid-modified polyolefin resins are thermoplastic resins in which acidic functional groups are introduced into polyolefin resins by graft polymerization or other methods. Examples of acidic functional groups include succinic anhydride, maleic anhydride, glutaric anhydride, phthalic anhydride, and other cyclic acid anhydrides. Furthermore, it is preferable that the acid-modified polyolefin resin has a melting point of 130°C or higher in the DSC method, more preferably 130 to 200°C, and even more preferably 135 to 180°C. By using an acid-modified polyolefin resin with a melting point within the above range, the difference in melting points between the acid-modified polyolefin resin and other components of the thermoplastic resin (B) becomes smaller, and the dispersibility of the acid-modified polyolefin resin in the thermoplastic resin (B) is further improved. As a result, the adhesion between the thermoplastic resin (B) and r-CF (A) is further improved.

[0066] The melting point in this specification is a value measured by differential scanning calorimetry (DSC) (measured using a Seiko Instruments DSC6200 differential scanning calorimetry instrument at a heating rate of 10°C / min).

[0067] Specific examples of acid-modified polyolefin resins include Admer QB550 (manufactured by Mitsui Chemicals, MFR 10g / 10 min), etc.

[0068] The amount of thermoplastic resin (B6x) blended is preferably 3 to 80% by mass, more preferably 5 to 75% by mass, and particularly preferably 10 to 40% by mass, based on 100% by mass of thermoplastic resin (B). It is preferable that the amount of thermoplastic resin (B6x) blended in thermoplastic resin (B) be within the above range because it is possible to achieve both tensile modulus and impact resistance.

[0069] [Thermoplastic resin (b)] A thermoplastic elastomer can be used as the thermoplastic resin (b). In this specification, "thermoplastic elastomer" refers to a polymer that softens and becomes plastic when heated to a suitable temperature, exhibits elasticity when cooled, and does not show a melting point when measured by DSC. To improve the adhesion between r-CF(A) and thermoplastic resin(B), it is preferable to incorporate thermoplastic resin(b). Thermoplastic resins (b) can be classified into acid-modified thermoplastic elastomers (thermoplastic resin (bx)) and non-acid-modified thermoplastic elastomers (thermoplastic resin (by)). It is preferable to use a thermoplastic resin (bx) to further improve the adhesion between r-CF(A) and the thermoplastic resin. Improved adhesion can enhance the elastic modulus and impact strength. It is preferable to include r-CF(A), any of the thermoplastic resins (B1) to (B6), and thermoplastic resin (b) because this significantly enhances compatibility and allows for the production of a thermoplastic resin composition with high impact resistance.

[0070] An "acid-modified thermoplastic elastomer" refers to a thermoplastic elastomer into which acidic functional groups have been introduced by graft polymerization or the like. Suitable examples of acid-modified thermoplastic elastomers include acid-modified styrene elastomers and acid-modified olefin elastomers. Acid modification refers to introducing cyclic acid anhydride groups or carboxylic acid groups into the copolymer side chains, for example, with cyclic acid anhydrides such as succinic anhydride, maleic anhydride, glutaric anhydride, and phthalic anhydride.

[0071] Examples of the styrene-based elastomer include block copolymers composed of polystyrene blocks and elastomer blocks with a polyolefin structure. Specific examples include styrene-isoprene-styrene block copolymer (SIS), hydrogenated styrene-ethylene-butylene-styrene block copolymer (SEPS), styrene-butylene-styrene block copolymer (SBS), hydrogenated styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-butadiene-isoprene-styrene block copolymer (SBIS), and hydrogenated styrene-butadiene-isoprene-styrene block copolymer (SEEPS).

[0072] Examples of the olefin-based elastomers include ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylate copolymer, ethylene-propylene-diene terpolymer, isoprene rubber, nitrile rubber, and polybutene rubber.

[0073] Polyester elastomers include copolymers of crystalline polyester (hard segment) and polyalkylene ether glycol (soft segment). Polyester elastomers (sometimes abbreviated as TPEE or TPC) are mainly classified into two types based on the structure of the soft segment: polyester-polyester type and polyester-polyether type. However, polymers with various characteristics can be synthesized depending on the specific structure and type of the soft segment, the specific structure and type of the hard segment, and their proportions. Polyester elastomers have excellent heat resistance and oil resistance, and exhibit excellent fusion properties with polycarbonate resins and styrene resins.

[0074] Specific examples of polyester elastomers include Hytrel 3046 (manufactured by Toray DuPont, MFR 10g / 10 min).

[0075] Examples of commercially available thermoplastic resins (bx) include maleic anhydride-modified isoprene rubber such as LIR-403 (manufactured by Kuraray Co., Ltd.); modified isoprene rubber such as LIR-410 (manufactured by Kuraray Co., Ltd.); carboxy-modified nitrile rubber such as Klynac 110, 221, 231 (manufactured by Polyser Corporation); maleic anhydride-modified polybutene such as Nippon Oil Corporation's Polybutene; ethylene methacrylic acid copolymer such as Nucrel (manufactured by Mitsui DuPont Polychemicals Co., Ltd.); ethylene methacrylic acid copolymer such as Yukalon (manufactured by Mitsubishi Chemical Corporation); maleic anhydride-modified ethylene-propylene rubber such as Tuffmer M (MA8510 (manufactured by Mitsui Chemicals)) and TX-1215 (manufactured by Mitsui Chemicals); maleic anhydride-modified ethylene-propylene rubber such as Tuffmer M (MH7020 (manufactured by Mitsui Chemicals)) Examples include butene rubber, HPR series (maleic acid-modified EEA (manufactured by Mitsui DuPont Polychemicals)), Bondine (maleic acid-modified EEA (manufactured by Atofina)), ToughTec (maleic acid-modified SEBS, M1943 (manufactured by Asahi Kasei)), Kraton (maleic acid-modified SEBS, FG1901X (manufactured by Kraton Polymers)), ToughPrene (maleic acid-modified SBS, 912 (manufactured by Asahi Kasei)), Septon (maleic acid-modified SEPS (manufactured by Kuraray)), Lexpearl (maleic acid-modified EEA, ET-182G, 224M, 234M (manufactured by Nippon Polyolefins)), Aurolene (maleic acid-modified EEA, 200S, 250S (manufactured by Nippon Paper Chemicals)), and other maleic acid-modified polyethylenes.

[0076] Examples of commercially available thermoplastic resins (by) include ethylene methacrylic acid copolymers such as Nucrel (manufactured by Mitsui DuPont Polychemicals); ethylene methacrylic acid copolymers such as Yukalon (manufactured by Mitsubishi Chemical Corporation); α-olefin copolymers such as Tuffmer (manufactured by Mitsui Chemicals); SEBS such as ToughTec (manufactured by Asahi Kasei Corporation); SBS such as ToughPrene (manufactured by Asahi Kasei Corporation); SEPS such as Septon (manufactured by Kuraray Co., Ltd.); and EEA such as Lexpearl (manufactured by Nippon Polyolefin Co., Ltd.).

[0077] Thermoplastic resin (b) can improve the impact resistance of the resulting r-CFRP, and the Charpy impact strength measured according to JIS K7111-1 was 20 kJ / m². 2 Preferably, it should be 30 kJ / m³ or more. 2 The above is more preferable. The upper limit of the Charpy impact strength of thermoplastic resin (b) is not particularly limited, and any that does not break can be suitably used.

[0078] The average MFR of thermoplastic resin (b) is preferably 1.0 g / 10 min or more, and more preferably 5.0 g / 10 min or more. Having the average MFR of thermoplastic resin (b) within the above range reduces the melt viscosity during processing, suppresses fiber breakage of r-CF(A) due to processing, and enables the development of high physical properties.

[0079] The amount of thermoplastic resin (b) blended is preferably 5 to 20% by mass, more preferably 5 to 15% by mass, and even more preferably 5 to 10% by mass, from the viewpoint of further improving both elastic modulus and impact resistance of 100% by mass of the thermoplastic resin composition.

[0080] The amount of thermoplastic resin (b) blended is preferably 3 to 30% by mass, more preferably 5 to 25% by mass, and even more preferably 7 to 20% by mass, based on 100% by mass of thermoplastic resin (B). By having the amount of thermoplastic resin (b) blended in thermoplastic resin (B) within the above range, it is possible to achieve a better balance between impact resistance and load deflection temperature.

[0081] <Other ingredients> The thermoplastic resin composition of the present invention may optionally contain other components that have been conventionally used to modify resins, such as inorganic fillers, weather stabilizers, light stabilizers, anti-aging agents, antioxidants, softeners, dispersants, fillers, colorants, lubricants, heat stabilizers, antistatic agents, ultraviolet absorbers, and flame retardants such as halogen-based, phosphorus-based, or metal oxides. Furthermore, alkali metal, alkaline earth metal, or zinc metal soaps, nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants may also be added.

[0082] Examples of inorganic fillers include silica, heat-dissipating fillers, talc, calcium silicate, wollastonite, montmorillonite, and hydrotalcite.

[0083] <Method for producing thermoplastic resin compositions> The thermoplastic resin composition can be produced by melt-kneading recycled carbon fiber (A) with at least two thermoplastic resins (B) having different elastic moduli. Specifically, the thermoplastic resin composition of the present invention, which exhibits a sea-island structure having domains (D) and a matrix (M) specified by the shield-aunt and elastic modulus, and satisfies (1) to (3), is obtained by kneading while controlling the shear of the compounding components at the temperature at which the thermoplastic resin (B) melts. For example, r-CF(A), thermoplastic resin(B), and various additives and colorants as needed can be mixed using a batch-type kneader such as a kneader, roll mill, super mixer, high-speed mixer, ball mill, sand mill, attritor, or Banbury mixer, or a single-screw extruder, twin-screw extruder, or rotor-type twin-screw kneader, to obtain a resin composition in the form of pellets, powder, granules, or beads. Since the degree of mixing can be controlled relatively easily and subsequent molding is straightforward, the method of forming the material into pellets using a twin-screw extruder is preferable.

[0084] The shape of the sea-island structure, which has domains (D) and a matrix (M) specified by the elastic modulus, can be controlled not only by the composition and blending ratio of the recycled carbon fibers (A) and thermoplastic resin (B) used, but also by the conditions during melt mixing. The share of the compounding components can be controlled by factors such as the temperature conditions during mixing, the discharge rate, the rotation speed, and the shape of the mixed components. For example, when manufacturing with a twin-screw extruder, control methods include changing the discharge rate, rotation speed, and the screw element of the mixing section, or supplying the thermoplastic resin (B) that constitutes the domain (D) from the middle section of the twin-screw extruder (hereinafter referred to as side feed). By changing the specifications of the manufacturing site and the thermoplastic resin (B) used, the maximum diameter and area of ​​the domain (D) can be controlled.

[0085] The thermoplastic resin composition can be used as a masterbatch, which is diluted with the molding resin during molding. The amount of r-CF(A) in 100% by mass of the masterbatch is preferably 35 to 70% by mass, and more preferably 40 to 65% by mass. By setting the amount of r-CF(A) within the above range, the productivity and mechanical properties of the masterbatch can be improved. In the masterbatch, the resin used for dilution during molding can be one of the thermoplastic resins (B) exemplified above. It is preferable to use the same resin as the thermoplastic resin (B) used for dispersing r-CF(A) due to its excellent compatibility. Because the thermoplastic resin composition has excellent dispersibility of r-CF(A), it can be molded stably even when used as a high-concentration resin composition such as a masterbatch.

[0086] Alternatively, a compound may be prepared by blending the required amount of r-CF(A) with thermoplastic resin(B) and molding it directly with a molding resin without dilution. When a thermoplastic resin composition is used as a compound, the amount of r-CF(A) in 100% by mass of the compound is preferably 10 to 40% by mass, and more preferably 15 to 30% by mass. Furthermore, by setting the amount of r-CF(A) within the above range and using two or more resins with different moduli, it is possible to achieve both high compound productivity and mechanical properties such as tensile modulus and impact resistance.

[0087] Recycled carbon fiber reinforced plastic The recycled carbon fiber reinforced plastic of the present invention is formed from a thermoplastic resin composition. The molding method is not particularly limited, and it can be manufactured by, for example, extrusion molding, injection molding, blow molding, etc. Since the thermoplastic resin composition has excellent strength and moldability, it is also suitable for forming automobile parts and other objects with complex shapes using injection-molded recycled carbon fiber reinforced plastic. Recycled carbon fiber reinforced plastics exhibit a sea-island structure having domains (D) and a matrix (M) specified by their elastic modulus, and satisfy conditions (1) to (3). Furthermore, if a thermoplastic resin composition exhibiting a sea-island structure with domains (D) and matrix (M) specified by the elastic modulus, and satisfying (1) to (3), is used as is without dilution with a diluent resin, the sea-island structure of the thermoplastic resin composition is maintained, and the domains (D) and matrix (M) when used as a reinforced plastic also satisfy (1) to (3).

[0088] The method for measuring (1) to (3) using recycled carbon fiber reinforced plastic is as described above. The sea-island structure in recycled carbon fiber reinforced plastic does not differ in the cross-section and planar view of the reinforced plastic. For example, it can be measured by cutting out a surface perpendicular to the flow direction of the resin composition during molding. (1) Maximum diameter (μm) and area (μm) of domain (D) 2 The average value of the circularity coefficient of domain (D), which can be obtained from the following formula (1), is between 1.0 and 2.5. (2) The average area of ​​domain (D) is 0.001 to 0.3 μm 2 That is the case. (3) The area ratio D:M between the domain (D) and the matrix (M) is 1:99 to 50:50. Circularity coefficient of domain (D) =(Maximum diameter of domain (D)) 2 ×π) / (4 × area of ​​domain (D))···Formula (1)

[0089] It is preferable to form recycled carbon fiber reinforced plastic using a thermoplastic resin composition that contains recycled carbon fibers (A) and at least two thermoplastic resins (B) with different elastic moduli, exhibits a sea-island structure having domains (D) and a matrix (M) specified by the elastic modulus, and satisfies (1) to (3) as is. [Examples]

[0090] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the examples. In addition, "parts" in the examples means "parts by mass", and "%" means "% by mass". Items not described with numerical values in the table indicate that they are not contained.

[0091] 《Measurement method》 The physical properties of each raw material were measured by the following methods. <Measurement of bulk density of recycled carbon fiber and non-recycled carbon fiber> The bulk density of r-CF(A) etc. was measured in accordance with JIS K5101. <Measurement of average MFR of thermoplastic resin (B)> The MFR of thermoplastic resin (B) etc. was measured in accordance with JIS K7210-1. <Measurement of tensile modulus of thermoplastic resin (B)> The tensile modulus of thermoplastic resin (B) was measured in accordance with JIS K7161. <Measurement of Charpy impact strength of thermoplastic resin (B)> The Charpy impact strength of acid-modified thermoplastic elastomer (b-1) and recycled carbon fiber reinforced plastic was measured in accordance with JIS K7111-1.

[0092] <Production of r-CF> 《Production Example 1》 CFRP derived from aircraft end materials was heat-treated at 750°C in a heated steam atmosphere for 4 hours. Subsequently, in air, it was heat-treated at 550°C for 6 hours to obtain a block of recycled carbon fiber. After crushing the obtained block of recycled carbon fiber with a cutting machine, fibers of 4 to 15 mm were recovered to obtain recycled carbon fiber (A-1) according to Production Example 1. The bulk density was 0.25 g / cm 3 It was.

[0093] 《Production Example 1》 Recycled carbon fiber (A-2) according to Production Example 2 was obtained in the same manner as in Production Example 1, except that CFRP derived from aircraft end materials was changed to CFRP derived from automotive parts waste materials. The bulk density was 0.10 g / cm 3 It was.

[0094] 《Raw materials》 The raw materials used in the examples are listed below. <cf> A'-1: Manufactured by Mitsubishi Chemical Corporation, bulk density 0.53 g / cm³ 3 Non-recycled carbon fiber

[0095] <Thermoplastic resin (B)> • B1-1: Amiran CM1041-LO (PA-6 resin, manufactured by Toray Industries, Inc.) МFR 20g / 10min (230℃, 2.16kgf), Tensile modulus: 2500 MPa, Charpy impact strength: 5.5 kJ / m 2 • B2-2: Acrypet TF-9 (PMMA resin, manufactured by Mitsubishi Chemical Corporation) MFR 20g / 10 min (230℃, 3.8kgf) Tensile modulus: 3300 MPa, Charpy impact strength: 1.3 kJ / m 2 • B3-3: Sebian T-500SF (ABS resin, manufactured by Daicel Mirise Co., Ltd.) MFR 25g / 10min (220℃, 10kgf), Tensile modulus of elasticity: 2000 MPa, Charpy impact strength: 14 kJ / m 2 • B4-4: Trecon 1401 x 06 (PBT resin, manufactured by Toray Industries, Inc.) MFR 20g / 10min (250℃, 2.16kgf), Tensile modulus: 2500 MPa, Charpy impact strength: 4.5 kJ / m 2 B5-5: Yupiron E-2000 (PC resin, manufactured by Mitsubishi Engineering Plastics Corporation) MFR 5g / 10min (300℃, 1.2kgf), Tensile modulus: 2300 MPa, Charpy impact strength: 8.8 kJ / m 2 • B6-6: J708UG (Block - PP resin, manufactured by Sun Allomer Co., Ltd.) MFR 45g / 10min (230℃, 2.16kgf), Tensile modulus: 1500 MPa, Charpy impact strength: 5.5 kJ / m² • B6-7: Sun Allomer PM900A (Homo PP resin, manufactured by Sun Allomer Co., Ltd.) MFR 2g / 10min (230℃, 2.16kgf), Tensile modulus: 1300 MPa, Charpy impact strength: 7.5 kJ / m 2 • B6-8: Acid-modified polypropylene resin, Admer QB550 (manufactured by Mitsui Chemicals, Inc.) MFR 30g / 10 minutes (230℃, 2.16kgf) Tensile modulus: 1600 MPa • B6-9: Acid-modified polypropylene resin, Admer QB550 (manufactured by Mitsui Chemicals, Inc.) MFR 10g / 10min (230℃, 2.16kgf) Tensile modulus: 900 MPa

[0096] [Thermoplastic elastomer (thermoplastic resin (b))] • b-1: Acid-modified styrene elastomer, ToughTec M1943 (manufactured by Asahi Kasei Chemicals Corporation) MFR 8.0g / 10 minutes (230℃, 2.16kgf) Tensile modulus (<10 MPa) • b-2: Acid-modified ethylene-propylene rubber, Toughmer MP0610 (manufactured by Mitsui Chemicals, Inc.) MFR 0.6g / 10min (190℃, 2.16kgf) Tensile modulus of elasticity: 100 MPa) b-3: Polyester elastomer, Hytrel 3046 (manufactured by Toray DuPont) MFR 10g / 10min (190℃, 2.16kgf) Tensile modulus (<50 MPa) b-4: Styrene-based elastomer, ToughTec H1221 (manufactured by Asahi Kasei Chemicals Corporation) MFR 5g / 10 minutes (230℃, 2.16kgf) Tensile modulus (<10 MPa) • b-5: Ethylene-propylene rubber, Toughmer DF640 (manufactured by Mitsui Chemicals, Inc.) MFR 3.6g / 10min (190℃, 2.16kgf) Tensile modulus (<50 MPa)

[0097] The type of thermoplastic resin (B) used and its modulus (tensile modulus) [MPa] are summarized below. [Table 1]

[0098] <Manufacturing of thermoplastic resin compositions> (Example 1) A thermoplastic resin composition was obtained by using 10 parts by mass of recycled carbon fiber (A-1) as r-CF(A), 85 parts by mass of thermoplastic resin (B1-1) and 5 parts by mass of thermoplastic resin (b-1) as thermoplastic resin (B), and extruding and granulating them in a twin-screw extruder (manufactured by Japan Steel Works, Ltd.) at 280°C, discharge rate of 20 kg / h, and rotation speed of 400 rpm (mixing condition 1). Next, the obtained thermoplastic resin composition was molded using an injection molding machine (manufactured by Toshiba Machine Co., Ltd.) to obtain a multipurpose test specimen measuring 800 mm in length, 10 mm in width, and 4 mm in thickness.

[0099] (Examples 2-21, Comparative Examples 1-4) Except for changing the materials, proportions (parts by mass), and mixing conditions shown in Table 2, thermoplastic resin compositions were prepared in the same manner as in Example 1, and then multipurpose test specimens were obtained. However, Examples 1-9 and 12-20 are for reference only. The mixing conditions are as follows: (Mixing condition 1) Twin-screw extruder (manufactured by Japan Steel Works, Ltd.); 280°C, discharge rate 20 kg / h, rotation speed 400 rpm (Mixing conditions 2) The resin with the higher modulus of elasticity was supplied from the base of the twin-screw extruder, while the resin with the lower modulus of elasticity was supplied from the side. The temperature was 280°C, discharge rate 20 kg / h, and rotation speed 400 rpm. (Mixing condition 3) Twin-screw extruder (manufactured by Japan Steel Works); 280°C, discharge rate 20 kg / h, rotation speed 200 rpm (Mixing condition 4) Twin-screw extruder (manufactured by Japan Steel Works, Ltd.); 220°C, discharge rate 20 kg / h, rotation speed 200 rpm (Mixing condition 5) Twin-screw extruder (manufactured by Japan Steel Works, Ltd.); 280°C, discharge rate 20 kg / h, rotation speed 1000 rpm (Mixing condition 6) Twin-screw extruder (manufactured by Japan Steel Works, Ltd.); 280°C, discharge rate 20 kg / h, rotation speed 50 rpm

[0100] [Table 2]

[0101] (Reference example 1) A thermoplastic resin composition was obtained by using 30 parts by mass of carbon fiber (A'-1) as non-recycled carbon fiber and 70 parts by mass of thermoplastic resin (B1-1) as thermoplastic resin (B), extruding them in a twin-screw extruder (manufactured by Japan Steel Works, Ltd.) at 280°C, discharge rate of 20 kg / h, and rotation speed of 400 rpm (mixing condition 1), and then granulating them. Next, the obtained thermoplastic resin composition was molded using an injection molding machine (manufactured by Toshiba Machine Co., Ltd.) to obtain a multipurpose test specimen measuring 800 mm in length, 10 mm in width, and 4 mm in thickness.

[0102] <Measurement and evaluation of thermoplastic resin compositions and reinforced plastics> Using multipurpose test specimens as thermoplastic resin compositions and reinforced plastics, physical properties were measured, image analyzed, and evaluated using the following methods. Since the sea-island structure of the multipurpose test specimens was almost identical to that of the thermoplastic resin compositions used, Table 3 shows the following values ​​measured using the multipurpose test specimens: circularity coefficient, average area, domain (D) to matrix (M) area ratio D:M, average aspect ratio of domain (D), and domain diameter D of domain (D). 90 Domain diameter D 10 The value obtained by dividing by (D 90 / D 10 The results of the following were shown.

[0103] <Preparation of elastic images of cross-sections> The thermoplastic resin composition and multipurpose test specimens were cut into 1.0-1.5 cm squares, and the samples were sanded with abrasive paper until they were 200-300 μm thick. These samples were then cut into 5-8 mm squares with a razor blade and placed on the sample stage of a cross-section polisher (IB-19520CCP, manufactured by JEOL Ltd.). The argon ion beam acceleration voltage was set to 5 kV to prepare cross-sections for observation. In Example 8, the elastic modulus image obtained by SPM measurement was acquired as an RGB color image (Figure 2), the image was imported into image analysis software (ImageJ), converted to 8-bit grayscale (black=0, white=255), and automatic binarization was performed using discriminant analysis (Figure 3). The average area, equivalent diameter, circularity coefficient, and aspect ratio were calculated from the number of pixels of each color in the domain (D) and matrix (M), and these were used as the average values. Comparative Example 2 and Reference Example 3 did not have a sea-island structure.

[0104] <Circularity coefficient of domain (D)> The elastic modulus images of the cross-sections of thermoplastic resin compositions and recycled carbon fiber reinforced plastics obtained by SPM measurement were acquired as RGB color images (Figure 2). These images were imported into image analysis software (ImageJ), converted to 8-bit grayscale (black=0, white=255), and automatically binarized using discriminant analysis. The maximum diameter (μm) and area (μm) of all selected domains (D) were calculated from the number of pixels of each color in the domain (D) and matrix (M). The circularity coefficient of the domain (D) was calculated from the maximum diameter (μm) and area (μm) using the following formula (1), and the average value was calculated. Here, the maximum diameter is the maximum length of the selected domain (D). The circularity coefficient of domain (D) = (the maximum diameter of domain (D)) 2 ×π) / (4 × area of ​​domain (D)) ···Formula (1)

[0105] <Average area of ​​domain (D)> <Area ratio between domain (D) and matrix (M) (D:M)> Elastic modulus images of cross-sections of thermoplastic compositions and recycled carbon fiber reinforced plastics obtained by SPM measurement were acquired as RGB color images (Figure 2). These images were imported into image analysis software (ImageJ), converted to 8-bit grayscale (black=0, white=255), and automatically binarized using discriminant analysis. The average area of ​​the domain (D) and the area ratio (D:M) of the domain (D) to the matrix (M) were calculated from the number of pixels of each color in the domain (D) and matrix (M).

[0106] <Average aspect ratio of domain (D)> The elastic modulus images of the cross-sections of thermoplastic resin compositions and recycled carbon fiber reinforced plastics obtained by SPM measurement were acquired as RGB color images (Figure 2). These images were imported into image analysis software (ImageJ), converted to 8-bit black and white (black=0, white=255), and automatically binarized using discriminant analysis. From the number of pixels of each color in the domain (D) and matrix (M), the numerical mean (μm) of the major axis length (maximum object width) and the numerical mean (μm) of the minor axis length (minimum object width) of the domain (D) were calculated using the following formula (2). Average aspect ratio = Average length of major axis ÷ Average length of minor axis ... Formula (2)

[0107] <D of Domain (D) 90 / D 10 > The elastic modulus images of the cross-sections of the resin composition and recycled carbon fiber reinforced plastic obtained by SPM measurement were acquired as RGB color images (Figure 2). These images were imported into image analysis software (ImageJ), converted to 8-bit black and white (black=0, white=255), and automatically binarized using discriminant analysis. The particle size distribution of all domains (D) was determined from the number of pixels of each color in the domain (D) and matrix (M), and the particle size distribution of the particle size (D) at which the cumulative volume is 10% was obtained. 10 ), and particle size (D) at which 90% is achieved. 90 Calculate the value of D 90 / D 10 They sought it. The thermoplastic resin compositions related to each example were evaluated as follows. The results are shown in Table 3.

[0108] <Evaluation of thermoplastic resin compositions> [Evaluation of productivity (deposits at the die tip)] When 5 kg of each thermoplastic resin composition, such as those in the examples, was produced under the conditions of the examples and comparative examples, the amount of deposit generated on the die at the tip of the extruder was evaluated according to the following criteria. [Evaluation Criteria] +++: Sediment weight is less than 1g. Productivity is particularly good. ++: The weight of the sediment is between 1g and 3g. Good productivity. + : The weight of the sediment is between 3g and 5g. Production is possible. NG: The weight of the sediment is 5g or more. Poor productivity.

[0109] <Evaluation of recycled carbon fiber reinforced plastics> The following evaluations were performed using the multipurpose test specimens related to each example. The results are shown in Table 3. γ) Evaluation of tensile modulus The tensile modulus was measured using the multipurpose test specimens obtained from each example, in accordance with JIS K7161. A higher measured value indicates superior strength. The evaluation criteria for the modulus are as follows. [Evaluation Criteria] +++: 10,000 MPa or higher. Excellent. ++: Above 8000MPa, below 10000MPa. Good. +: 5000 MPa or higher, less than 8000 MPa. Practical range. NG: Less than 5000MPa. Defective.

[0110] δ) Evaluation of impact resistance The impact resistance of each of the obtained multipurpose test specimens was measured using notched Charpy impact strength in accordance with JIS K7111-1. The evaluation criteria are as follows: [Evaluation Criteria] +++: 15kJ / m 2 That's all. Excellent. ++7kJ / m 2 More than 15kJ / m 2 Less than. Good. +: 5kJ / m 2 More than 7kJ / m 2 Less than. The usable range. NG: 5kJ / m 2 less than. For applications requiring high strength, such as automotive parts, a Charpy impact strength of 7 kJ / m² is sufficient. 2 It is preferable that the above conditions are met.

[0111] [Table 3]

[0112] From the above results, it was found that even when using recycled carbon fibers, thermoplastic resin compositions manufactured to have a sea-island structure in which the miscibility state satisfies (1) to (3) in at least two thermoplastic resins (B) with different elastic moduli exhibited excellent productivity. The recycled carbon fiber reinforced plastic formed from this thermoplastic resin composition exhibited excellent not only tensile modulus but also impact resistance. Thus, it was confirmed that even when using recycled carbon fibers, it is possible to achieve excellent effects equivalent to those of reinforced plastics using non-recycled carbon fibers, as shown in the reference example.< / cf>

Claims

1. A thermoplastic resin composition for recycled carbon fiber reinforced plastics, It contains recycled carbon fiber (A) and at least two thermoplastic resins (B) with different elastic moduli. It exhibits a sea-island structure having domains (D) and matrices (M) specified by the elastic modulus, and is characterized by satisfying the following (1) to (3): Thermoplastic resin composition. (1) Maximum diameter (μm) and area (μm) of domain (D) ２ The average value of the circularity coefficient of domain (D), which can be obtained from the following formula (1), is between 1.0 and 2.

5. (2) The average area of ​​domain (D) is 0.012 to 0.02 μm ２ That is the case. (3) The area ratio D:M between the domain (D) and the matrix (M) is 1:99 to 50:

50. Circularity coefficient of domain (D) = (Maximum diameter of domain (D)) ２ ×π) / (4 × area of ​​domain (D)) ... Formula (1)

2. The thermoplastic resin composition according to claim 1, characterized in that the average aspect ratio of domain (D) is 1.0 to 2.

0.

3. Domain (D) Domain diameter D ９０ Domain diameter D １０ The thermoplastic resin composition according to claim 1, characterized in that the value obtained by dividing by is 1.5 to 25.

4. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin (B) comprises an acid-modified thermoplastic elastomer.

5. A recycled carbon fiber reinforced plastic formed from the thermoplastic resin composition according to any one of claims 1 to 4.

6. It contains recycled carbon fiber (A) and at least two thermoplastic resins (B) with different elastic moduli. A recycled carbon fiber reinforced plastic characterized by having a sea-island structure with domains (D) and a matrix (M) specified by the elastic modulus, and satisfying the following conditions (1) to (3). (1) Maximum diameter (μm) and area (μm) of domain (D) ２ The average value of the circularity coefficient of domain (D), which can be obtained from the following formula (1), is between 1.0 and 2.

5. (2) The average area of ​​domain (D) is 0.012 to 0.02 μm ２ That is the case. (3) The area ratio D:M between the domain (D) and the matrix (M) is 1:99 to 50:

50. Circularity coefficient of domain (D) = (Maximum diameter of domain (D)) ２ ×π) / (4 × area of ​​domain (D)) ... Formula (1)

7. Recycled carbon fiber (A) and at least two thermoplastic resins (B) with different elastic moduli are melt-mixed together. The thermoplastic resin composition exhibits a sea-island structure having domains (D) and a matrix (M) specified by the elastic modulus, and satisfies the following conditions (1) to (3): A method for producing a thermoplastic resin composition for reinforcing recycled carbon fibers. (1) The average value of the circularity coefficient of the domain (D) obtained from the maximum diameter (μm) and area (μm ２ ) of the domain (D) by the following formula (1) is 1.0 to 2.

5. (2) The average area of ​​domain (D) is 0.012 to 0.02 μm ２ That is the case. (3) The area ratio D:M between the domain (D) and the matrix (M) is 1:99 to 50:

50. Circularity coefficient of domain (D) = (Maximum diameter of domain (D)) ２ ×π) / (4 × area of ​​domain (D)) ... Formula (1)

Images