JP2024042946A - Thermoplastic resin composition for recycled carbon fiber-reinforced plastic, and recycled carbon fiber-reinforced plastic - Google Patents

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

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.

Carbon fiber reinforced plastics (hereinafter sometimes referred to as CFRP), which are reinforced with carbon fiber (hereinafter sometimes referred to as CF), are used in a wide range of fields, including industrial products such as sporting goods and aircraft parts. Wind turbine rotor blades, which have traditionally used glass fiber composite materials, are being replaced with lightweight, high-strength CFRP in order to improve efficiency and increase size.

Furthermore, in parts for automobiles and aircraft where safety is important, there are many scraps of intermediate products produced in the CFRP manufacturing process. Furthermore, in addition to the increasing demand for CFRP, the lifespan of CFRP used in aircraft parts is said to be approximately 20 years, so CFRP waste is expected to continue to increase. For this reason, recycled carbon fiber reinforced plastics (hereinafter sometimes referred to as r-CFRP) using recycled carbon fibers (hereinafter sometimes referred to as r-CF), which are carbon fibers recovered from CFRP waste materials, etc., are being considered. has been done.

Until now, used CFRP waste materials and offcuts generated in the CFRP manufacturing process (prepreg, sheet molding compound, etc.) have been disposed of in landfills after being crushed. Collection methods are being considered.

For example, Patent Document 1 describes, as a method for recovering r-CF, a method in which CFPR is crushed into scales and then carbonized at a temperature range of 300 to 1,000°C in a substantially non-oxidizing atmosphere; A method is disclosed in which CFPR is carbonized in a substantially non-oxidizing atmosphere at a temperature range of 300 to 1,000° C. and then crushed into scales. Patent Document 2 describes a method for obtaining r-CF from CFRP containing CF and matrix resin, in which the matrix resin is thermally decomposed by heating CFRP, and the resin residue content is 0.01 to 30.0% by mass. A method for producing r-CF is disclosed in which a heat-treated product is obtained and the heat-treated product is cut.

As for r-CFRP using r-CF, Patent Document 3 discloses an r-CFRP obtained using a resin and r-CF that has a fiber length variation coefficient of 20% or more and does not contain a sizing agent. Patent Document 4 discloses an r-CFRP that contains r-CF, a polyolefin resin, and a dispersant having a basic group. This r-CF has an average fiber length of 0.05 to 15.0 mm, and the amount of r-CF in 100% by mass of r-CFRP is 1 to 50% by mass.

Japanese Unexamined Patent Publication No. 7-118440 JP 2020-075493 A JP 2019-163354 Publication JP2020-176244A

In addition, the strength required of reinforced plastics is not only the tensile modulus, which indicates the hardness of the material itself when force is applied slowly, but also the strength to disperse the force when force is applied momentarily. Both impact resistance and impact resistance are required.
However, in recycled carbon fiber reinforced plastics, it is possible to make reinforced plastics with improved tensile modulus by kneading r-CF into the resin, but r-CF has poor compatibility with the resin and cannot be kneaded into the resin. Even if the extrusion is attempted, extrusion is not stable, resulting in poor productivity and problems with impact resistance, and currently it is not possible to achieve both tensile modulus and impact resistance.

Therefore, the present invention was made in view of the above background, and is a recycled carbon fiber reinforced plastic that has excellent productivity even when recycled carbon fiber is used, and has excellent not only tensile modulus but also impact resistance. The purpose of the present invention is to provide a resin composition for recycled carbon fiber-reinforced plastics that can form a recycled carbon fiber-reinforced plastic, and a recycled carbon fiber-reinforced plastic using the same.

As a result of extensive investigations, the present inventors have found that the problems of the present invention can be solved in the following aspect, and have thus completed the present invention.
[1]: A thermoplastic resin composition for recycled carbon fiber reinforced plastics,
The present invention comprises recycled carbon fibers (A) and at least two types of thermoplastic resins (B) having different elastic moduli,
The polymer has an island-in-a-sea structure having a domain (D) and a matrix (M) that are determined by an elastic modulus, and is characterized in that the polymer satisfies the following (1) to (3):
Thermoplastic resin composition.
(1) The average circularity coefficient of the domains (D) calculated from the maximum diameter (μm) and area (μm ² ) of the domains (D) according to the following formula (1) 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) to the matrix (M) is 1:99 to 50:50.
Circularity factor 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 the domains (D) is 1.0 to 2.0.
[3]: The thermoplastic resin composition according to [1] or [2], characterized in that the value obtained by dividing the domain diameter _D90 of the domain (D) by the domain diameter _D10 is 1.5 to 25.
[4]: The thermoplastic resin composition according to any one of [1] to [3], wherein the thermoplastic resin (B) contains an acid-modified thermoplastic elastomer.
[5]: A recycled carbon fiber reinforced plastic formed from the thermoplastic resin composition according to any one of [1] to [4].
[6]: Contains recycled carbon fibers (A) and at least two types of thermoplastic resins (B) having different elastic moduli;
A recycled carbon fiber reinforced plastic exhibits an island-in-a-sea structure having domains (D) and a matrix (M) specified by elastic modulus, and satisfies the following (1) to (3):

(1) The average circularity coefficient of the domains (D) calculated from the maximum diameter (μm) and area (μm ² ) of the domains (D) according to the following formula (1) 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) to the matrix (M) is 1:99 to 50:50.

Circularity factor of domain (D)=(maximum diameter of domain (D) ² ×π)/(4×area of domain (D)) (Formula (1))
[7]: Recycled carbon fibers (A) and at least two thermoplastic resins (B) having different elastic moduli are melt-kneaded;
The thermoplastic resin composition has an island-in-a-sea structure having domains (D) and a matrix (M) specified by an elastic modulus, and satisfies the following (1) to (3):
A method for producing a thermoplastic resin composition reinforced with recycled carbon fibers.
(1) The average circularity coefficient of the domains (D) calculated from the maximum diameter (μm) and area (μm ² ) of the domains (D) according to the following formula (1) 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) to 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)

According to the present invention, even when recycled carbon fibers are used, it is possible to form a thermoplastic resin composition for recycled carbon fiber reinforced plastics with excellent productivity, and the recycled carbon fiber reinforced plastics obtained thereby have a tensile modulus of elasticity of and can have excellent impact resistance.

Examples of elastic modulus images of SPM measurements of cross sections of r-CFRP of Examples and Comparative Examples. An elastic modulus image of SPM measurement of the cross section of r-CFRP of Example 8. An analysis image obtained by binarizing the elastic modulus image of the SPM measurement of the cross section of r-CFRP of Example 8 using image processing software. 13 shows examples of maximum and minimum object widths of a domain (D) in Example 8.

An example of the thermoplastic resin composition and recycled carbon fiber reinforced plastic according to the present disclosure will be described below.
It should be noted that other embodiments are also included in the scope of the present invention as long as they are consistent with the spirit of the present invention. In addition, in this specification, a numerical range specified using "..." includes the numerical values written before and after "...".
In this specification, recycled carbon fiber is referred to as r-CF, and carbon fiber (i.e., non-recycled carbon fiber) is referred to as CF, and recycled carbon fiber reinforced plastic is referred to as r-CFRP, and carbon fiber reinforced plastic (i.e., non-recycled carbon fiber reinforced plastic) is referred to as CFRP.
In addition, "non-recycled carbon fiber reinforced plastic and/or recycled carbon fiber reinforced plastic" may be referred to as "reinforced plastic".
In addition, unless otherwise noted, the various components appearing in this specification may each be used independently as a single type, or as a combination of two or more types.
The numerical values specified in this specification are values determined by the methods disclosed in the embodiments or examples.

《Thermoplastic resin composition》
The thermoplastic resin composition of the present invention is used to form a recycled carbon fiber reinforced plastic, and includes recycled carbon fiber (A) (hereinafter also referred to as r-CF (A)) and at least two types having different elastic moduli. Thermoplastic resin (B).
As a result of extensive studies by the present inventors, it has been found that thermoplastic It was found that the compatibility between the resin and the recycled carbon fibers was significantly improved, the thermoplastic resin composition had excellent productivity, and the resulting recycled carbon fiber reinforced plastics had improved tensile modulus and impact resistance. As a result, even recycled carbon fiber can be strengthened to the same extent as non-recycled carbon fiber, and parts that have traditionally been made of metal can be replaced with r-CFRP, which has excellent lightweight properties. We can expect that.

(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 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 domain (D) = (maximum diameter of domain (D) ² × π) / (4 × area of domain (D)) ... Formula (1)

<Domain (D) and matrix (M)>
The thermoplastic resin composition and recycled carbon fiber reinforced plastic have a sea-island structure having a domain (D) and a matrix (M).
The sea-island structure in a thermoplastic resin composition is formed by using multiple thermoplastic resins, and is controlled by the characteristics of the materials used, such as the compatibility and elastic modulus of the thermoplastic resins, and the kneading conditions of the resin composition. can do.
The sea-island structure of the present invention is formed from at least two types of thermoplastic resins having different moduli of elasticity. It is preferable that the domain (D) is formed from a thermoplastic resin with a low modulus of elasticity, and the matrix (M) is formed from a thermoplastic resin with a high modulus of elasticity.
As a result, the boundaries of at least two types of thermoplastic resins are clearly divided into a domain (D) and a matrix (M) derived from the thermoplastic resin due to the difference in elastic modulus, and a sea-island structure is observed.
The sea-island structure is identified by observing the cross sections of the resin composition and recycled carbon fiber reinforced plastic using a scanning probe microscope (hereinafter also abbreviated as SPM), and based on the detected difference in elastic modulus. SPM is a microscope that observes the surface state of a sample by scanning the surface of the sample while tapping it with a minute probe (cantilever). In addition to the general surface shape represented by unevenness, the peak value of the voltage generated during tapping corresponds to the elastic modulus of the surface to be measured, so the voltage peak value can be used as an image of the magnitude of the elastic modulus of the surface. can be expressed. Specifically, the cross sections of the resin composition and recycled carbon fiber reinforced plastic are observed using an Oxford Instruments MFP-3D with a cantilever: AC-160TS and dynamic measurement mode. The measurement range is 5 μm x 5 μm, and the elastic modulus image is observed.
Methods for obtaining a cross section to be observed with SPM include breaking the target sample frozen with liquid nitrogen, etc. (freeze-fracture method), cutting the target sample with a sharp blade such as a razor (microtome method), or cutting the target sample with a cutter, etc. There is a method (ion milling method) in which the cross-section of the target sample is prepared using abrasive paper, and the sample is irradiated with an ion beam using a cross-section polisher device (ion milling method). Ion milling is most preferred.
The sea-island structure having domains (D) and matrices (M) does not change greatly depending on the flow direction of the thermoplastic resin composition during molding, and it does not change greatly depending on the flow direction of the thermoplastic resin composition during molding. , the form of the sea-island structure is the same.

"Circular coefficient of domain (D)"
The average value of the circular coefficient (hereinafter also abbreviated as circular coefficient) of the domain (D), which is calculated from the maximum diameter (μm) and area (μm ² ) of the domain (D) using the following formula (1), is 1.0 to It is 2.5.
Circularity coefficient of domain (D) = (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 is the maximum object width (μm) in FIG.

The circularity coefficient is an index representing circularity, and it can be determined whether the shape of the domain (D) is close to a circle or not (the smaller the value, the closer to a circle). When the average value of the circularity coefficient is 1.0 to 2.5, the effect of improving the tensile modulus and impact resistance can be obtained. The circularity coefficient is preferably 1.1 to 2.0, more preferably 1.1 to 1.5.
If the circularity coefficient is larger than 2.5, the force upon impact cannot be dispersed, resulting in a decrease in impact resistance.

"Average area of domain (D)"
The average area of the domains (D) is 0.001 to 0.5 μm ² . More preferably, it is 0.003 to 0.3 μm ² . If it is smaller than 0.001 μm ² , the thermoplastic resin will be excessively dispersed, impairing cushioning properties upon impact and reducing impact resistance. If it is larger than 0.5 μm ² , poor dispersion causes poor compatibility between the thermoplastic resin and r-CF, resulting in a decrease in impact resistance and tensile modulus.
The average area of the domain (D) is determined from the number of pixels of each color of the domain (D) and matrix (M) by binarizing the elastic modulus image obtained by the SPM using the free software "ImageJ".

"Area ratio of domain (D) to matrix (M)"
The content ratio of the domains (D) and the matrix (M) in the sea-island structure in the present invention is domain (D)≦matrix (M). The area ratio (D):(M) of the domains (D) and the matrix (M) is 1:99 to 50:50. From the viewpoint of the tensile modulus of elasticity, it is preferably 5:95 to 40:60, and more preferably 5:95 to 30:70. When the content ratio of the domains (D) is greater than that of the matrix (M), the tensile modulus of elasticity is significantly reduced.
The area ratio (D):(M) is determined from the number of pixels of each color of the domain (D) and matrix (M) by binarizing the elastic modulus image obtained by the SPM described above using the free software "ImageJ". The ratio of the domain (D) increases when the content ratio of the thermoplastic resin with a low elastic modulus is increased.

"Average aspect ratio of domain (D)"
The average aspect ratio of the domain (D), which is calculated from the number average value (μm) of the maximum object width and the number average value (μm) of the minimum object width of the domain (D) using the following formula (2), is 1.0 to 2. Preferably, it is 0. It is more preferably from 1.0 to 1.8, even more preferably from 1.0 to 1.5.
Average aspect ratio = number average value of major axis length ÷ number average value of short axis length... 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 an elastic modulus image obtained by SPM using free analysis software "ImageJ" and measuring the result.

"Domain diameter"
In the present invention, the domain diameter refers to the area of the domain (D) obtained by binarizing the elastic modulus image of the cross section of the resin composition or recycled carbon fiber reinforced plastic using SPM using the free analysis software "ImageJ". The equivalent circle diameter was determined, and the particle diameter values at which the cumulative volume was 10%, 50%, and 90% were defined as domain diameters D ₁₀ , D ₅₀ , and D ₉₀ , respectively. The equivalent circle diameter is the diameter of an equivalent circle having the same area as the area of the domain (D), and is determined by the following formula.
Equivalent circle diameter = 2√ (area/π)
The domain diameter D ₁₀ is preferably 0.005 to 0.04 μm, more preferably 0.01 to 0.03 μm. The domain diameter D ₅₀ is preferably 0.01 to 0.1 μm, more preferably 0.02 to 0.08 μm. The domain diameter D ₉₀ is preferably 0.05 to 1.0 μm, more preferably 0.1 to 0.5 μm. Being within this range is effective in improving impact resistance. Examples of methods for adjusting the domain diameter include adjusting the degree of kneading during production of the resin composition.

" _D90 / _D10 "
The value obtained by dividing the domain diameter D ₉₀ by the domain diameter D ₁₀ (hereinafter also abbreviated as D ₉₀ /D ₁₀ ) is preferably 1.5 to 25. It is more preferably from 2 to 15, and even more preferably from 5 to 10.
By setting the various domain diameters within the above ranges, a resin composition containing a mixture of large and small domains (D) is formed, which is preferable because the impact resistance can be further improved compared to a case where the domain diameters are uniform. If D ₉₀ /D ₁₀ is smaller than 1.5, the domain diameter will be uniform, making it unsuitable for dispersing received impact. If the compatibility between the domain-forming resin and the matrix-forming resin is poor, D ₉₀ /D ₁₀ will be greater than 25, resulting in poor productivity and impact resistance.

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

From the viewpoint of maintaining good strength of the thermoplastic resin composition containing r-CF(A), the lower limit of the carbon content of r-CF(A) is preferably 80% by mass or more. The carbon content of r-CF(A) is preferably 95.0% by mass or less. Note that r-CF(A) may contain other elements such as nitrogen, silicon, sodium, and sulfur within a range that does not affect the effects of the present invention.

The fiber length of r-CF(A) is preferably 0.05 mm or more in order to further increase the tensile modulus and impact resistance. There is no particular upper limit, but considering availability, a fiber length of 20 mm or less is preferable.

Commercial products of r-CF(A) include, for example, CARBISO MF series (average fiber length 0.08 to 0.1 mm) and CARBISO C series (average fiber length 3 to 10 mm).
Note that the average fiber length can be determined by the following method.
For example, the recycled carbon fiber is observed using a scanning electron microscope (manufactured by JEOL, JSM-6700M) at an accelerating voltage of 5 kV, and a 50,000x image (pixel count: 1024 x 1280) is taken. . Next, the average fiber length can be determined by measuring the long axis length of each of the 20 arbitrary recycled carbon fibers in the photographed image.

From the viewpoint of further increasing the productivity of the thermoplastic resin composition, the bulk density of r-CF (A) is preferably 0.03 to 1.0 g/cm ^3. By using r-CF (A) having a bulk density in this range, it is possible to effectively suppress the fiber from being retained at the supply port when r-CF (A) is supplied to the production equipment in the production of the thermoplastic resin composition, and to increase the productivity. A more preferable range of the bulk density of r-CF (A) is 0.05 to 1.0 g/cm ³ , and a further more preferable range is 0.1 to 1.0 g/cm ^3. By adjusting the rotation speed of the grinder rotary blade and the opening of the classification mesh, etc., r-CF (A) having a bulk density of 0.05 to 1.0 g/cm ³ can be obtained.
The bulk density can be measured using a Scott volume meter (manufactured by Tsutsui Rikagaku Kiki Co., Ltd.) by pouring the recycled carbon fiber into a cylindrical container from the top of the measuring device, measuring the mass of a certain volume of sample that has been leveled off at the point where it has become heaped, and calculating the bulk density based on the ratio of this mass to the container volume, according to the following formula (3).
Bulk density (g/mL) = (mass (g) of a certain volume of recycled carbon fiber after wearing off) ÷ (container volume (mL)) ... Formula (3)

From the viewpoint of achieving both impact resistance and productivity, the blending amount of r-CF (A) is preferably 10 to 50% by mass, and preferably 15 to 40% by mass, based on 100% by mass of the thermoplastic resin composition. The content is more preferably 20 to 40% by mass.

<Thermoplastic resin (B)>
Thermoplastic resin is a resin that softens and becomes plastic when heated to an appropriate temperature, and solidifies when cooled.
The thermoplastic resin composition of the present invention contains at least two thermoplastic resins (B) having different moduli of elasticity. The thermoplastic resin (B) is not particularly limited, and the resin part of the thermoplastic resin composition exhibits a sea-island structure having a domain (D) and a matrix (M) specified by the elastic modulus, and (1) to ( If 3) can be satisfied, various choices are possible.
In addition, the elastic modulus in this invention refers to the tensile elastic modulus measured based on JISK7161.

As the thermoplastic resin (B), various selections can be made as long as it is at least two kinds of thermoplastic resins with different elastic moduli. However, it is preferable that the elastic modulus (E M ) of the thermoplastic resin constituting the matrix ( _M ) and the elastic modulus (E _D ) of the thermoplastic resin constituting the domain (D) are
Elastic modulus (E _M )>Elastic modulus (E _D )
It is preferable that the following relationship is satisfied.
The elastic modulus (E _M ) of the thermoplastic resin constituting the matrix (M) is preferably 1000 to 8000 MPa from the viewpoint of impact resistance, and more preferably 1000 to 5000 MPa from the viewpoint of ease of orientation of the recycled carbon fibers. The elastic modulus (E _D ) of the thermoplastic resin constituting the domain (D) is preferably in the range of 1 to 1500 MPa, and more preferably in the range of 1 to 1000 MPa.
Furthermore, the difference between the elastic modulus (E _M ) and the elastic modulus (E _D ) (elastic modulus (E _M ) - elastic modulus (E _D )) is preferably 500 MPa or more, and more preferably 1000 MPa or more.
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 requirement.

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

Among them, polyamide resins (hereinafter also referred to as thermoplastic resins (B1)), acrylic resins (hereinafter also referred to as thermoplastic resins (B2)), styrene-based resins (hereinafter also referred to as thermoplastic resins (B3)), etc. , polyester resin (hereinafter also referred to as thermoplastic resin (B4)), polycarbonate resin (hereinafter also referred to as thermoplastic resin (B5)), and polyolefin resin (hereinafter also referred to as thermoplastic resin (B6)). The thermoplastic resin (B1) or the thermoplastic resin (B4) is preferably selected from the group consisting of: thermoplastic resin (B1) or thermoplastic resin (B4) from the viewpoint of balance between cost and mechanical properties.
However, the thermoplastic resins (B1), (B2), (B3), (B4), (B5), and (B6) are not thermoplastic elastomers.

These thermoplastic resins (B1), (B2), (B3), (B4), (B5), or (B6) are combined with a thermoplastic elastomer (hereinafter also referred to as thermoplastic resin (b)). It is preferable to use it from the viewpoint of compatibility between the recycled carbon fiber (A) and the thermoplastic resin (B).
Further, the thermoplastic resin (b) is preferably an acid-modified thermoplastic elastomer (hereinafter also referred to as thermoplastic resin (bx)).

Further, when using a thermoplastic resin (B6), it is preferable to use a combination of a non-acid-modified polyolefin resin and an acid-modified polyolefin resin.

Specifically, preferred combinations of thermoplastic resins (B) include, for example, thermoplastic resin (B1) and thermoplastic resin (b), thermoplastic resin (B2) and thermoplastic resin (b), and 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 the thermoplastic resin (b) is a thermoplastic resin (bx).
In addition, from the viewpoint of ease of handling and cost as a reinforced plastic, thermoplastic resins (B1) and thermoplastic resins (bx), or polyolefin resins that are not acid-modified and acid-modified polyolefin resins as thermoplastic resins (B6). and a thermoplastic resin (B6x).

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

Further, when using an acid-modified polyolefin resin, the content of the acid-modified polyolefin resin is preferably 1 to 40% by mass, and 1 to 30% by mass based on the total 100% by mass of the thermoplastic resin (B). More preferably, 5 to 20% by mass is even more preferred.
When the content of the 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 tip of the die can be further suppressed. As a result, productivity can be improved.

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

When containing an acid-modified polyolefin resin and a thermoplastic elastomer, the total content of the acid-modified polyolefin resin and thermoplastic elastomer can be adjusted based on the total of 100% by mass of the thermoplastic resin (B), since high physical properties can be achieved. , based on a total of 100% by mass of the thermoplastic resin (B), preferably from 3 to 30% by mass, more preferably from 5 to 25% by mass, even more preferably from 7 to 20% by mass.

The thermoplastic resin (B) preferably has an average MFR of 10 g/min or more, more preferably 20 g/min or more. Since the average MFR of the thermoplastic resin (B) is 10 g/min or more, the melt viscosity when r-CF (A) and the thermoplastic resin (B) are kneaded decreases, and the Since destruction can be suppressed, high mechanical properties can be exhibited. The upper limit of the average MFR of the thermoplastic resin (B) is not particularly limited, but from the viewpoint of availability, it is usually 200 g/min or less.

The MFR of the resin can be determined by measuring in accordance with JIS K7210-1.

[Thermoplastic resin (B1): polyamide resin (PA resin)]
A polyamide resin (PA resin) can be used as the thermoplastic resin (B1). However, the thermoplastic resin (B1) is excluded if it is a thermoplastic elastomer.
Specific examples of the thermoplastic resin (B1) include -[NH(CH ₂ ) ₅ CO]-, -[NH(CH ₂ ) ₆ NHCO(CH ₂ ) ₄ CO]-, -[NH(CH ₂ ) ₆ NHCO (CH ₂ ) ₈ CO]-, -[NH(CH ₂ ) ₁₀ CO]-, -[NH(CH ₂ ) ₁₁ CO]-, and -[NH(CH ₂ ) ₂ NHCO-D-CO]-( In the formula, D represents an unsaturated hydrocarbon having 3 to 4 carbon atoms) A polyamide resin having a structural unit of at least one member selected from the group consisting of unsaturated hydrocarbons having 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, and 6/12 copolymer nylon. Nylon, 6/66/11 copolymer nylon, 6/66/12 copolymer nylon, 6/66/11/12 copolymer nylon, 6/66/610/11/12 copolymer nylon, dimer acid polyamide resin, etc. can be mentioned.

Specific examples of the 6-nylon resin include Amilan CM1041-LO (manufactured by Toray Industries, Inc., MFR: 21 g/10 min), Amiran CM1007 (manufactured by Toray Industries, Inc., MFR: 21 g/10 min), Unitika Nylon A1020LP (manufactured by Unitika Inc., MFR: 109 g/10 minutes), etc.

Specific examples of the 66-nylon resin include Amilan CM3001N (manufactured by Toray Industries, Inc., MFR: 103 g/10 min).

[Thermoplastic resin (B2): Acrylic resin]
The thermoplastic resin (B2) may be an acrylic resin, except that the thermoplastic resin (B2) is a thermoplastic elastomer.
The thermoplastic resin (B2) can be obtained by polymerizing a (meth)acrylic monomer. Examples of the monomer include a (meth)acrylic monomer having an alkyl group, a (meth)acrylic monomer having a hydroxyl group, a (meth)acrylic monomer having a carboxyl group, a (meth)acrylic monomer having a glycidyl group, and an acrylic monomer having a vinyl ester group such as vinyl acetate or vinyl propionate. Among them, polymethyl methacrylate (PMMA) resin, which is a polymer of methyl methacrylate, is preferred because it can achieve a high elastic modulus.
The thermoplastic resin (B2) is preferably an acrylic resin having a glass transition temperature of 0° C. or higher.

Specific examples of the acrylic resin (B2) include Acrypet TF-9 (manufactured by Mitsubishi Chemical Corporation, MFR 20 g/10 minutes).

[Thermoplastic resin (B3): styrene resin]
A styrene resin can be used as the thermoplastic resin (B3). However, the thermoplastic resin (B3) is excluded if it is a thermoplastic elastomer.
The thermoplastic resin (B3) is a resin containing a styrene monomer as a monomer. In addition to homopolymers of styrene monomers, examples include styrene resins obtained by copolymerizing other vinyl monomers or rubbery polymers that can be copolymerized with these as needed. .
The thermoplastic resin (B3) is preferably a styrene resin having a glass transition temperature of 0° C. or higher.

Examples of styrene monomers include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, methoxystyrene, and monobromostyrene. , dibromustyrene, fluorostyrene, tribromostyrene, and other styrene derivatives, and styrene is particularly preferred from the viewpoint of excellent moldability.

Other vinyl monomers that can be copolymerized with styrene-based 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 esters of methacrylic acid such as phenyl methacrylate and benzyl methacrylate, and methyl methacrylate. Examples of such methacrylic acid alkyl esters include acrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, cyclohexyl methacrylate, and dodecyl methacrylate; epoxy group-containing methacrylic acid esters such as glycidyl methacrylate; maleimide monomers such as maleimide, N-methylmaleimide, and N-phenylmaleimide; and α,β-unsaturated carboxylic acids and their anhydrides such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, phthalic acid, and itaconic acid.

Examples of rubbery polymers that can be copolymerized with styrene monomers include polybutadiene, polyisoprene, styrene/butadiene random copolymers and block copolymers, acrylonitrile/butadiene copolymers, acrylic acid alkyl esters, and methacrylates. Acid alkyl ester and butadiene copolymers, diene copolymers such as butadiene/isoprene copolymers, ethylene/propylene random copolymers and block copolymers, ethylene/butene random copolymers and block copolymers Copolymers of ethylene and α-olefins such as ethylene and α-olefins, copolymers of ethylene and unsaturated carboxylic acid esters such as ethylene/methyl methacrylate copolymers, ethylene/butyl acrylate copolymers, ethylene/vinyl acetate copolymers Copolymers of ethylene and aliphatic vinyl such as, ethylene, propylene and non-conjugated diene terpolymers such as ethylene-propylene-hexadiene copolymers, acrylic rubbers such as butyl polyacrylate, and polyorganosiloxane rubber components. Examples include composite rubbers having a structure in which the polyalkyl (meth)acrylate rubber component is intertwined with each other so that they cannot be separated.

Examples of styrenic 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 Examples include resins such as polymers (AAS resins), acrylonitrile/ethylene propylene rubber/styrene copolymers (AES resins), styrene/IPN rubber copolymers, or mixtures thereof.

Furthermore, examples of rubbery polymers copolymerizable with styrene monomers include polymers made of polybutadiene or polyisoprene, whose unsaturated bonds are hydrogenated. Specific examples in such a case 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 preferable because of its good compatibility with r-CF(A), and has good impact resistance. Acrylonitrile-butadiene-styrene copolymer (ABS resin) is more preferred because it has good properties.

Specific examples of ABS resins include Cevian T-500SF (manufactured by Daicel Miraize Co., Ltd., MFR 25 g/10 min).

[Thermoplastic resin (B4): polyester resin]
A polyester resin can be used as the thermoplastic resin (B4). However, the thermoplastic resin (B4) is excluded if it is a thermoplastic elastomer.
Thermoplastic resins (B4) include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexele dimethylene terephthalate (PCT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), liquid crystal polyester, etc. As a suitable thermoplastic resin (B4), for example, a thermoplastic resin consisting of a saturated dicarboxylic acid and a saturated dihydric alcohol can be used.
Saturated dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, naphthalene-1,4- or 2,6-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenyldicarboxylic acids, diphenoxyethanediethanedicarboxylic acids Aromatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, aliphatic dicarboxylic acids such as decane-1,10-dicarboxylic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid can be used.

Saturated dihydric alcohols include aliphatic glycols such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, hexamethylene glycol, dodecamethylene glycol, and neopentyl glycol. , alicyclic glycols such as cyclohexanedimethanol, 2,2-bis(4'-β-hydroxyethoxyphenyl)propane, and other aromatic diols.

Specific examples of the polyester resin include TORAYCON 1401×06 (PBT resin, manufactured by Toray Industries, Inc., MFR 25 g/10 minutes).

[Thermoplastic resin (B5): Polycarbonate resin (PC resin)]
Polycarbonate resin (PC resin) can be used as the thermoplastic resin (B5). However, the thermoplastic resin (B5) is excluded if it is a thermoplastic elastomer.
As the thermoplastic resin (B5), for example, a resin 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, such as an interfacial method when using phosgene, and a transesterification method in which the resin is reacted in a molten state when using a carbonic acid diester.

Examples of the aromatic dihydroxy compound 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; bis(hydroxyaryl)cycloalkanes such as 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, and other dihydroxydiaryl ethers, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, and other dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide, and other dihydroxydiaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone, and other dihydroxydiaryl sulfones.
In addition to these, piperazine, dipiperidylhydroquinone, resorcin, and 4,4'-dihydroxydiphenyls may be used in combination.Furthermore, branched aromatic polycarbonate resins using polyfunctional compounds such as phloroglucinone in combination may also be used.

Examples of the carbonate precursor to be reacted with the aromatic dihydroxy compound include phosgene, diaryl carbonates such as diphenyl carbonate and ditolyl carbonate, and dialkyl carbonates such as dimethyl carbonate and diethyl carbonate.

Specific examples of the PC resin include Iupilon E-2000 (manufactured by Mitsubishi Engineering Plastics, MFR 5g/10 minutes).

[Thermoplastic resin (B6): polyolefin resin]
A polyolefin resin can be used as the thermoplastic resin (B6). However, the thermoplastic resin (B6) is excluded if it is a thermoplastic elastomer.
Examples of the thermoplastic resin (B6) include homopolymers of α-olefins having about 2 to 8 carbon atoms, such as ethylene, propylene, and 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, Examples include (co)polymers with other α-olefins having about 2 to 18 carbon atoms, such as 1-decene and 1-octadecene.

Specifically, ethylene homopolymers, ethylene-propylene copolymers, ethylene-1-butene, such as linear low-density polyethylene resin (LLDPE), low-density polyethylene resin (LDPE), and high-density polyethylene resin (HDPE) Copolymer, ethylene-propylene-1-butene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-1-heptene copolymer, ethylene-1- Ethylene copolymers such as ethylene resins such as octene copolymers, propylene homopolymers (homo PP), propylene-ethylene block copolymers (block PP), propylene-ethylene random copolymers (random PP) ), propylene-based resins such as propylene-based copolymers such as propylene-ethylene-1-butene copolymer, propylene-ethylene-4-methyl-1-pentene copolymer, propylene-ethylene-1-hexene copolymer, etc. can be mentioned. These polyolefin resins may be used alone or in combination of two or more. Propylene-based resins are preferred because they can achieve high mechanical properties, and propylene homocopolymers (homo-PP) are particularly preferred because they can increase the deflection temperature under load.

Specific examples of polyolefin resins include Prime Polypro J229E (manufactured by Prime Polymer Co., Ltd., random PP, MFR 50 g/10 min), Prime Polypro J708UG (block PP, MFR 45 g/10 min), Sunalomer PM900A (manufactured by Sun Allomer Co., Ltd., homo PP, MFR 30 g). /10 minutes).

"Thermoplastic resin (B6x)"
An acid-modified polyolefin resin can be used as the thermoplastic resin (B6x). However, the thermoplastic resin (B6x) is excluded if it is a thermoplastic elastomer.
The use of thermoplastic resin (B6x) is preferable because it improves the compatibility between r-CF (A) and thermoplastic resin (B) and increases adhesion.
Moreover, it is more preferable that the thermoplastic resin (B6x) is an acid-modified propylene resin since high mechanical properties can be achieved.
Among these, it is preferable to use a combination of a non-acid-modified polyolefin resin and an acid-modified polyolefin resin from the viewpoint of ease of handling as a reinforced plastic and cost. It is also preferable because it can significantly improve compatibility and produce a thermoplastic resin composition with high impact resistance.

Acid-modified polyolefin resin is a thermoplastic resin in which acidic functional groups are introduced into polyolefin resin by graft polymerization or the like. Examples of the acidic functional group include cyclic acid anhydrides such as succinic anhydride, maleic anhydride, glutaric anhydride, and phthalic anhydride.
Further, it is preferably an acid-modified polyolefin resin having a melting point of 130°C or higher as measured by the DSC method, more preferably a melting point of 130 to 200°C, and still more preferably a melting point of 135 to 180°C. By using an acid-modified polyolefin resin with a melting point in the above range, the difference in melting point with 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. do. Therefore, the adhesion between the thermoplastic resin (B) and r-CF (A) is further improved.

The melting point in this specification is a value measured by differential scanning calorimetry (DSC) (measured value obtained at a heating rate of 10° C./min with a suggested scanning calorimeter DSC6200 manufactured by Seiko Instruments).

A specific example of the acid-modified polyolefin resin includes Admer QB550 (manufactured by Mitsui Chemicals, MFR 10 g/10 minutes).

The blending amount of the thermoplastic resin (B6x) 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 the thermoplastic resin (B). It is preferable that the blending amount of the thermoplastic resin (B6x) in the thermoplastic resin (B) be within the above range, since it is possible to achieve both tensile modulus and impact resistance.

[Thermoplastic resin (b)]
A thermoplastic elastomer can be used as the thermoplastic resin (b).
In this specification, the term "thermoplastic elastomer" refers to a polymer that softens and becomes plastic when heated to an appropriate temperature, exhibits elasticity when cooled, and does not exhibit a melting point when measured by DSC.
In order to improve the adhesion between r-CF (A) and thermoplastic resin (B), it is preferable to blend thermoplastic resin (b).
The thermoplastic resin (b) can be classified into an acid-modified thermoplastic elastomer (thermoplastic resin (bx)) and a non-acid-modified thermoplastic elastomer (thermoplastic resin (by)).
It is preferable to use a thermoplastic resin (bx) in order to further improve the adhesion between r-CF (A) and the thermoplastic resin. By improving adhesion, elastic modulus and impact strength can be improved.
Including r-CF (A), any one of the thermoplastic resins (B1) to (B6), and the thermoplastic resin (b) significantly increases the compatibility and creates a thermoplastic resin composition with high impact resistance. It is preferable because it can be manufactured.

"Acid-modified thermoplastic elastomer" refers to a thermoplastic elastomer with an acidic functional group introduced through graft polymerization or the like. Preferred examples of acid-modified thermoplastic elastomers include acid-modified styrene elastomers and acid-modified olefin elastomers. Acid modification refers to the introduction of cyclic acid anhydride groups or carboxylic acid groups into the copolymer side chains using, for example, cyclic acid anhydrides such as succinic anhydride, maleic anhydride, glutaric anhydride, and phthalic anhydride. .

As the styrene-based elastomer, a block copolymer constituted by a polystyrene block and an elastomer block having a polyolefin structure can be exemplified. Specific examples include styrene isoprene styrene block copolymer (SIS), hydrogenated styrene-ethylene-butylene-styrene block copolymer (SEPS), styrene-butylene-styrene block copolymer (SBS), styrene- Hydrogenated products of ethylene-butylene-styrene block copolymer (SEBS), styrene-butadiene-isoprene-styrene block copolymer (SBIS), hydrogenated product of styrene-butadiene-isoprene-styrene block copolymer (SEEPS) etc.

Examples of the olefin elastomer include ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-ethyl acrylate copolymer, and ethylene. -Methacrylate copolymer, ethylene-propylene-diene terpolymer, isoprene rubber, nitrile rubber, polybutene rubber and the like.

Examples of the polyester elastomer include copolymers of crystalline polyester (hard segment) and polyalkylene ether glycol (soft segment). Polyester elastomers (sometimes abbreviated as TPEE or TPC) Polyester elastomers are mainly classified into two types, polyester-polyester type and polyester-polyether type, depending on the structure of the soft segment described above. Polymers with various characteristics can be synthesized depending on the specific structure and type of the hard segment, the specific structure and type of the hard segment, and their ratio.
Polyester elastomers have excellent heat resistance and oil resistance, and have excellent fusion properties with polycarbonate resins and styrene resins.

A specific example of a polyester elastomer is Hytrel 3046 (manufactured by DuPont-Toray Co., Ltd., MFR 10 g/10 min).

Commercially available thermoplastic resins (bx) include, for example, maleic anhydride-modified isoprene rubber such as LIR-403 (manufactured by Kuraray); modified isoprene rubber such as LIR-410 (manufactured by Kuraray); Kleinac 110, 221, Carboxy-modified nitrile rubber such as 231 (manufactured by Polycer); maleic anhydride-modified polybutene such as Nisseki Polybutene (manufactured by Nippon Oil Co., Ltd.); ethylene methacrylic acid copolymer such as Nuclell (manufactured by DuPont Mitsui Polychemicals); Yucalon (Mitsubishi Ethylene methacrylic acid copolymers such as Kagaku Co., Ltd.; maleic anhydride modified ethylene-propylene rubbers such as Tafmer M (MA8510 (Mitsui Chemicals)) and TX-1215 (Mitsui Chemicals); Tafmer M (MH7020 (Mitsui Chemicals)); Maleic anhydride modified ethylene-butene rubber such as (manufactured by Mitsui Chemicals); HPR series (maleic anhydride modified EEA (manufactured by Mitsui DuPont Polychemicals)); Bondine (maleic anhydride modified EEA (manufactured by Atofina)); Tuftec (maleic anhydride-modified SEBS, M1943 (manufactured by Asahi Kasei Corporation)), Kraton (maleic anhydride-modified SEBS, FG1901X (manufactured by Kraton Polymers)), Tufprene (maleic anhydride-modified SBS, 912 (manufactured by Asahi Kasei Corporation)), Septon (Maleic anhydride modified SEPS (manufactured by Kuraray)), Rexpar (maleic anhydride modified EEA, ET-182G, 224M, 234M (manufactured by Nippon Polyolefin Co., Ltd.)), Aulauren (maleic anhydride modified EEA, 200S, 250S ( Examples include maleic anhydride-modified polyethylene such as Nippon Paper Chemical Co., Ltd.).

Commercially available thermoplastic resins (by) include, for example, ethylene methacrylic acid copolymers such as Nucrel (manufactured by DuPont-Mitsui Polychemicals); ethylene methacrylic acid copolymers such as Yukalon (manufactured by Mitsubishi Chemical); α-olefin copolymers such as Tufmer (manufactured by Mitsui Chemicals); SEBS such as Tuftec (manufactured by Asahi Kasei); SBS such as Tufprene (manufactured by Asahi Kasei); SEPS such as Septon (manufactured by Kuraray); and EEA such as Rexpearl (manufactured by Japan Polyolefins).

The thermoplastic resin (b) preferably has a Charpy impact strength of 20 kJ/m ² or more, and 30 kJ/m 2 or more, as measured in accordance with JIS K7111-1, since it can increase the impact resistance of the resulting r- ^CFRP . It is more preferable that The upper limit of the Charpy impact strength of the thermoplastic resin (b) is not particularly limited, and those that do not break can be suitably used.

The average MFR of the thermoplastic resin (b) is preferably 1.0 g/10 minutes or more, more preferably 5.0 g/10 minutes or more. When the average MFR of the thermoplastic resin (b) is within the above range, the melt viscosity during processing is reduced, fiber breakage of r-CF (A) due to processing can be suppressed, and high physical properties can be exhibited. .

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

The blending amount of the thermoplastic resin (b) is preferably 3 to 30% by weight, more preferably 5 to 25% by weight, even more preferably 7 to 20% by weight based on 100% by weight of the thermoplastic resin (B). When the blending amount of the thermoplastic resin (b) in the thermoplastic resin (B) is within the above range, it is possible to achieve both impact resistance and deflection temperature under load.

<Other ingredients>
The thermoplastic resin composition of the present invention may contain an inorganic filler, a weathering stabilizer, a light stabilizer, an antioxidant, an antioxidant, a softener, a dispersant, a filler, a coloring agent, a lubricant, a heat stabilizer, and a heat stabilizer, as necessary. Other components conventionally blended for modifying resins, such as antistatic agents, ultraviolet absorbers, halogen-based, phosphorus-based, or metal oxide flame retardants, may also be blended. Further, metal soaps of alkali metals, alkaline earth metals, or zinc, nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants may be added.

Inorganic fillers include silica, heat dissipating fillers, talc, calcium silicate, wollastonite, montmorillonite, and hydrotalcite.

<Method of producing thermoplastic resin composition>
The thermoplastic resin composition can be produced by melt-kneading recycled carbon fibers (A) and at least two types of thermoplastic resins (B) having different elastic moduli.
Specifically, the thermoplastic resin composition of the present invention, which exhibits an island-in-a-sea structure having domains (D) and a matrix (M) specified by the elastic modulus and satisfies the requirements (1) to (3), can be obtained by kneading the components while controlling the shear applied to them at a temperature at which the thermoplastic resin (B) melts.
For example, r-CF (A), thermoplastic resin (B), and, if necessary, various additives and colorants are added, and the mixture is kneaded using a batch mixer such as a kneader, a roll mill, a super mixer, a high-speed mixer, a ball mill, a sand mill, an attritor, or a Banbury mixer, a single-screw extruder, a twin-screw extruder, or a rotor-type twin-screw kneader to form a resin composition in the form of pellets, powder, granules, or beads.
The method of pelletizing the mixture using a twin-screw extruder is preferred because it is relatively easy to control the degree of kneading and the subsequent molding process is easy.

The shape of the sea-island structure having the domain (D) and matrix (M) specified by the elastic modulus is determined by the composition and blending amount of the recycled carbon fiber (A) and thermoplastic resin (B) used, as well as the melt mixing. It can be controlled by the conditions at the time of training.
The share of the ingredients can be controlled by adjusting the temperature conditions during kneading, the discharge amount, the rotation speed, the shape of the kneading parts, etc. For example, when manufacturing with a twin-screw extruder, the discharge amount, rotation speed, and screw element of the kneading section are changed, and the thermoplastic resin (B) constituting the domain (D) is supplied from the middle part of the twin-screw extruder (hereinafter referred to as , side feed), etc., and by changing the specifications of the manufacturing site and the thermoplastic resin (B) used, the maximum diameter, area, etc. of the domain (D) can be controlled.

The thermoplastic resin composition can be used as a masterbatch which is diluted with a molding resin during molding.
The amount of r-CF(A) in 100% by mass of the masterbatch is preferably 35 to 70% by mass, more preferably 40 to 65% by mass. By setting the blending amount of r-CF(A) within the above range, the productivity and mechanical properties of the masterbatch can be improved. In the masterbatch, as the resin to be diluted during molding, those exemplified as the above-mentioned thermoplastic resin (B) can be used. It is preferable to use the same resin as the thermoplastic resin (B) used for dispersing r-CF (A) because it has excellent compatibility. Since the thermoplastic resin composition has excellent dispersibility of r-CF(A), it can be stably molded even when it is made into a highly concentrated resin composition such as a masterbatch.

Alternatively, a necessary amount of r-CF (A) may be blended with the thermoplastic resin (B) to form a compound that is molded as is without being diluted with a molding resin.
When the thermoplastic resin composition is made into a compound, the amount of r-CF(A) in 100% by mass of the compound is preferably 10 to 40% by mass, more preferably 15 to 30% by mass. In addition, by setting the amount of r-CF (A) in the above range and using two or more resins with different elastic moduli, it is possible to achieve both compound productivity and mechanical properties such as tensile elastic modulus and impact resistance. Can be done.

《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 can be manufactured by, for example, extrusion molding, injection molding, blow molding, or the like. Since thermoplastic resin compositions have excellent strength and moldability, it is also suitable for forming automobile parts having complex shapes using injection recycled carbon fiber reinforced plastics.
The recycled carbon fiber reinforced plastic exhibits a sea-island structure having a domain (D) and a matrix (M) specified by the elastic modulus, and satisfies (1) to (3).
In addition, a thermoplastic resin composition exhibiting a sea-island structure having a domain (D) and a matrix (M) specified by the elastic modulus and satisfying (1) to (3) is used as it is, and is diluted with a diluent resin etc. When not used, the sea-island structure of the thermoplastic resin composition is maintained as it is, and the domain (D) and matrix (M) when made into a reinforced plastic also satisfy (1) to (3).

The method for measuring (1) to (3) using recycled carbon fiber reinforced plastic is as described above, and the sea-island structure in recycled carbon fiber reinforced plastic has no difference in the cross section and plane of the reinforced plastic, for example, It can be measured by cutting out a plane perpendicular to the flow direction of the resin composition during molding.

(1) The average value of the circularity coefficient of the domain (D) determined from the maximum diameter (μm) and area (μm ² ) of the domain (D) using the following formula (1) is 1.0 to 2.5.
(2) The average area of the domain (D) is 0.001 to 0.3 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 domain (D) = (maximum diameter of domain (D) ² × π) / (4 × area of domain (D)) ... Formula (1)

The recycled carbon fiber reinforced plastic contains recycled carbon fibers (A) and at least two types of thermoplastic resins (B) having different elastic moduli, and is a sea island having a domain (D) and a matrix (M) specified by the elastic modulus. It is preferable to use a thermoplastic resin composition that exhibits a structure and satisfies (1) to (3) as is.

Hereinafter, the present invention will be explained in more detail based on Examples, but the present invention is not limited to the Examples. Further, in the examples, "part" means "part by mass", and "%" means "% by mass". Note that items without numerical values in the table indicate that they are not contained.

"Measuring 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 the thermoplastic resin (B) and the like was measured in accordance with JIS K7210-1.
<Measurement of tensile modulus of thermoplastic resin (B)>
The tensile modulus of the thermoplastic resin (B) was measured in accordance with JIS K7161.
<Measurement of Charpy impact strength of thermoplastic resin (B)>
The Charpy impact strength of the acid-modified thermoplastic elastomer (b-1) and the recycled carbon fiber reinforced plastic was measured in accordance with JIS K7111-1.

<Production of r-CF>
《Production example 1》
CFRP derived from aircraft scraps was heat treated in a heated steam atmosphere at 750°C for 4 hours. Subsequently, a recycled carbon fiber mass was obtained by heat treatment at 550° C. for 6 hours in air. The obtained recycled carbon fiber mass was crushed with a cutter and fibers of 4 to 15 mm were collected to obtain recycled carbon fiber (A-1) according to Production Example 1. The bulk density was 0.25 g/cm ³ .

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 the CFRP derived from aircraft scraps was changed to CFRP derived from scrap automobile parts. The bulk density was 0.10 g/ ^cm3 .

"material"
The raw materials used in Examples are shown below.
<CF>
・A'-1: Non-recycled carbon fiber manufactured by Mitsubishi Chemical Corporation, bulk density 0.53 g/cm ³

<Thermoplastic resin (B)>
・B1-1: Amilan CM1041-LO (PA-6 resin, manufactured by Toray Industries)
МFR 20g/10min (230℃, 2.16kgf),
Tensile modulus 2500MPa, Charpy impact strength 5.5kJ/ ^m2
・B2-2: Acrypet TF-9 (PMMA resin, manufactured by Mitsubishi Chemical Corporation)
МFR 20g/10min (230℃, 3.8kgf),
Tensile modulus: 3300MPa, Charpy impact strength: 1.3kJ/ ^m2
・B3-3: Cevian T-500SF (ABS resin, manufactured by Daicel Millize)
MFR 25g/10min (220℃, 10kgf),
Tensile modulus: 2000MPa, Charpy impact strength: 14kJ/ ^m2
・B4-4: Torrecon 1401×06 (PBT resin, manufactured by Toray Industries)
MFR 20g/10min (250℃, 2.16kgf),
Tensile modulus 2500MPa, Charpy impact strength 4.5kJ/ ^m2
・B5-5: Iupilon E-2000
(PC resin, manufactured by Mitsubishi Engineering Plastics)
MFR 5g/10min (300℃, 1.2kgf),
Tensile modulus: 2300MPa, Charpy impact strength: 8.8kJ/ ^m2
・B6-6: J708UG (Block-PP resin, manufactured by Sun Allomer)
MFR 45g/10min (230℃, 2.16kgf),
Tensile modulus 1500MPa, Charpy impact strength 5.5kJ/m2
・B6-7: Sunallomer PM900A (homo PP resin, manufactured by Sunallomer)
MFR 2g/10min (230℃, 2.16kgf),
Tensile modulus: 1300MPa, Charpy impact strength: 7.5kJ/ ^m2
・B6-8: Acid-modified polypropylene resin, Admar QB550 (manufactured by Mitsui Chemicals, Inc.,
MFR30g/10min (230℃, 2.16kgf),
Tensile modulus 1600MPa))
・B6-9: Acid-modified polypropylene resin, Admer QB550 (manufactured by Mitsui Chemicals, Inc.,
MFR10g/10min (230℃, 2.16kgf),
Tensile modulus 900MPa))

[Thermoplastic elastomer (thermoplastic resin (b))]
・b-1: Acid-modified styrene elastomer, Tuftec M1943 (manufactured by Asahi Kasei Chemicals,
MFR8.0g/10min (230℃, 2.16kgf),
Tensile modulus <10MPa)
・b-2: Acid-modified ethylene-propylene rubber, Tafmer MP0610 (manufactured by Mitsui Chemicals, Inc.,
MFR0.6g/10min (190℃, 2.16kgf),
Tensile modulus 100MPa)
・b-3: Polyester elastomer, Hytrel 3046 (manufactured by DuPont Toray,
MFR10g/10min (190℃, 2.16kgf),
Tensile modulus <50MPa)
・b-4: Styrene elastomer, Tuftec H1221 (manufactured by Asahi Kasei Chemicals,
MFR5g/10min (230℃, 2.16kgf),
Tensile modulus <10MPa)
・b-5: Ethylene-propylene rubber, Tafmer DF640 (manufactured by Mitsui Chemicals, Inc.,
MFR3.6g/10min (190℃, 2.16kgf),
Tensile modulus <50MPa)

The type and elastic modulus (tensile modulus) [MPa] of the thermoplastic resin (B) used are summarized below.

<Production of Thermoplastic Resin Composition>
Example 1
A thermoplastic resin composition was obtained by extruding 10 parts by mass of recycled carbon fiber (A-1) as r-CF (A), 85 parts by mass of thermoplastic resin (B1-1) as thermoplastic resin (B), and 5 parts by mass of thermoplastic resin (b-1) in a twin-screw extruder (manufactured by Japan Steel Works, Ltd.) at 280° C., discharge of 20 kg/h, and rotation speed of 400 rpm (kneading condition 1) and granulating the mixture.
The resulting thermoplastic resin composition was then molded using an injection molding machine (manufactured by Toshiba Machine Co., Ltd.) to obtain a multipurpose test piece measuring 800 mm long x 10 mm wide x 4 mm thick.

(Examples 2 to 21, Comparative Examples 1 to 4)
Thermoplastic resin compositions were produced in the same manner as in Example 1, except that the materials and blending amounts (parts by mass) and kneading conditions shown in Table 2 were changed, and then multipurpose test pieces were obtained. .
Note that the kneading conditions are as follows.
(Kneading conditions 1)
Twin screw extruder (manufactured by Japan Steel Works); 280°C, discharge 20kg/h, rotation speed 400rpm
(Kneading conditions 2)
The resin with higher elastic modulus was fed from the base of the twin-screw extruder, and the resin with lower elastic modulus was fed from the side. 280℃, discharge 20kg/h, rotation speed 400rpm
(Kneading condition 3)
Twin screw extruder (manufactured by Japan Steel Works); 280°C, discharge 20kg/h, rotation speed 200rpm
(Kneading condition 4)
Twin screw extruder (manufactured by Japan Steel Works); 220°C, discharge 20kg/h, rotation speed 200rpm
(Kneading condition 5)
Twin screw extruder (manufactured by Japan Steel Works); 280°C, discharge 20kg/h, rotation speed 1000rpm
(Kneading condition 6)
Twin-screw extruder (manufactured by Japan Steel Works); 280°C, discharge 20kg/h, rotation speed 50rpm

(Reference example 1)
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), a twin screw extruder (manufactured by Japan Steel Works, Ltd.) was used. A thermoplastic resin composition was obtained by extrusion (kneading conditions 1) and granulation at 280° C., a discharge rate of 20 kg/h, and a rotation speed of 400 rpm.
Subsequently, the obtained thermoplastic resin composition was molded using an injection molding machine (manufactured by Toshiba Machinery Co., Ltd.) to obtain a multipurpose test piece measuring 800 mm long x 10 mm wide x 4 mm thick.

≪Measurement and evaluation of thermoplastic resin compositions and reinforced plastics≫
Using multi-purpose test pieces as the thermoplastic resin composition and the reinforced plastic, physical property value measurements, image analysis, and evaluation were performed by the following methods. Since the sea-island structure of the multipurpose test piece had almost the same results as the properties of the thermoplastic resin composition used, Table 3 shows the circularity coefficient, average area, domain (D), and matrix measured using the multipurpose test piece. (M) area ratio D:M, average aspect ratio of domain (D), domain diameter D ₉₀ of domain (D) divided by domain diameter D ₁₀ (D ₉₀ /D ₁₀ ).

<Preparation of cross-sectional elastic image>
Thermoplastic resin compositions and multi-purpose test pieces were cut into 1.0 to 1.5 cm square pieces, ground with abrasive paper until the thickness reached 200 to 300 μm, and the samples were cut into 5 to 8 mm square pieces with a razor. The specimen was placed on a specimen stand (IB-19520CCP manufactured by JEOL Ltd.), and the acceleration voltage of the argon ion beam was set to 5 kV to prepare a cross section for observation.
Taking Example 8 as an example, the elastic modulus image obtained by SPM measurement is acquired as an RGB color image (Figure 2), the image is imported into image analysis software (ImageJ), and black and white 8 bits (black = 0, Image conversion is performed to white = 255), automatic binarization processing is performed using the discriminant analysis method (Figure 3), and the average area, equivalent circle diameter, and circular shape are calculated from the number of pixels of each color of domain (D) and matrix (M). Coefficients and aspect ratios were calculated and their average values were used.
Note that Comparative Example 2 and Reference Example 3 did not have a sea-island structure.

<Circular coefficient of domain (D)>
The elastic modulus image of the cross section of the thermoplastic resin composition and recycled carbon fiber reinforced plastic obtained by SPM measurement was obtained as an RGB color image (Figure 2), and the image was imported into image analysis software (ImageJ) and converted into a black and white 8-bit image. (black = 0, white = 255), automatic binarization processing using the discriminant analysis method is performed, and all domains (D) and matrix (M) selected from the number of pixels of each color are The maximum diameter (μm) and area (μm) of D) were calculated. From the maximum diameter (μm) and area (μm), the circularity coefficient of the domain (D) determined by the following mathematical formula (1) was determined, and the average value was calculated. Here, the maximum diameter is the maximum length of the selected domain (D).
Circularity coefficient of domain (D) = (maximum diameter of domain (D) ² × π) / (4 × area of domain (D)) ... Formula (1)

<Average area of domain (D)>
<Area ratio of domain (D) and matrix (M) (D:M)>
The elastic modulus images of the cross sections of the thermoplastic compositions and recycled carbon fiber reinforced plastics obtained by SPM measurements were obtained as RGB color images (Figure 2), and the images were imported into image analysis software (ImageJ) and converted into black and white 8-bit ( The image is converted to (black = 0, white = 255), automatic binarization processing is performed using the discriminant analysis method, and the average area of the domain (D) is calculated from the number of pixels of each color of the domain (D) and matrix (M). And the area ratio (D:M) of the domain (D) and matrix (M) was calculated.

<Average aspect ratio of domain (D)>
The elastic modulus image of the cross section of the thermoplastic resin composition and recycled carbon fiber reinforced plastic obtained by SPM measurement was obtained as an RGB color image (Figure 2), and the image was imported into image analysis software (ImageJ) and converted into a black and white 8-bit image. (black = 0, white = 255), perform automatic binarization processing using discriminant analysis method, and calculate the length of domain (D) from the number of pixels of each color in domain (D) and matrix (M). It was determined from the number average value (μm) of the axial length (maximum object width) and the number average value (μm) of the short axis length (minimum object width) using the following formula (2).
Average aspect ratio = number average value of major axis length ÷ number average value of short axis length... Formula (2)

< _D90 / _D10 of domain (D)>
The elastic modulus images of the cross sections of the resin composition and recycled carbon fiber reinforced plastic obtained by SPM measurement were obtained as RGB color images (Figure 2), and the images were imported into image analysis software (ImageJ) and converted into black and white 8-bit (black and white) images. = 0, white = 255), perform automatic binarization processing using discriminant analysis, and calculate all the particles of domain (D) from the number of pixels of each color of domain (D) and matrix (M). The diameter distribution was determined, and the values of the particle diameter (D ₁₀ ) at which the cumulative volume becomes 10% and the particle diameter (D ₉₀ ) at which the cumulative volume becomes 90% were calculated, and D ₉₀ /D ₁₀ was determined.
The following evaluations were performed on the thermoplastic resin compositions according to each example. The results are shown in Table 3.

<Evaluation of thermoplastic resin composition>
[Evaluation of productivity (deposits at the tip of the die)]
When 5 kg of the thermoplastic resin composition of each example was produced under the conditions of the example and comparative example, evaluation was made based on the following criteria based on the amount of deposits generated on the die at the tip of the extruder.
[Evaluation criteria]
+++: The weight of the deposit is less than 1 g. Productivity is particularly good.
++: The weight of the deposit is 1 g or more and less than 3 g. Good productivity.
+: The weight of the deposit is 3 g or more and less than 5 g. Production possible.
NG: The weight of the deposit is 5g or more. Poor productivity.

<Evaluation of recycled carbon fiber reinforced plastics>
The following evaluations were performed using the multipurpose test pieces according to each example. The results are shown in Table 3.
γ) Evaluation of tensile elastic modulus The tensile elastic modulus was measured according to JIS K7161 using the obtained multipurpose test pieces of each example. The higher the measured value, the better the strength. The evaluation criteria for elastic modulus are as follows.
[Evaluation criteria]
+++: 10000MPa or more. Are better.
++: 8000 MPa or more, less than 10000 MPa. Good.
+: 5000 MPa or more, less than 8000 MPa. Practical range.
NG: Less than 5000MPa. Bad.

δ) Evaluation of impact resistance Using the obtained multipurpose test pieces of each example, impact resistance was measured by Charpy impact strength with a notch according to JIS K7111-1. The evaluation criteria are as follows.
[Evaluation criteria]
+++: 15kJ/ ^m2 or more. Are better.
++7kJ/m2 or ^more , less than 15kJ/ ^m2 . Good.
+: 5kJ/m2 or ^more , less than 7kJ/ ^m2 . Practical range.
NG: Less than 5kJ/ ^m2 .
For applications requiring high strength such as automobile parts, it is preferable that the Charpy impact strength is 7 kJ/m ² or more.

From the above results, even when recycled carbon fiber is used, at least two types of thermoplastic resins (B) with different elastic moduli have a sea-island structure in which the compatibility state satisfies (1) to (3). The thermoplastic resin composition manufactured in 1997 had excellent productivity, and the recycled carbon fiber reinforced plastic formed from this thermoplastic resin composition had excellent not only tensile modulus but also impact resistance. As a result, it was confirmed that even when recycled carbon fibers were used, the same excellent effects as the reinforced plastic using non-recycled carbon fibers shown in the reference example were exhibited.

Claims (7)

A thermoplastic resin composition for recycled carbon fiber reinforced plastics, comprising:
Contains recycled carbon fiber (A) and at least two thermoplastic resins (B) having different moduli of elasticity,
It exhibits a sea-island structure having a domain (D) and a matrix (M) specified by the elastic modulus, and is characterized by satisfying the following (1) to (3):
Thermoplastic resin composition.

(1) The average value of the circularity coefficient of the domain (D) determined from the maximum diameter (μm) and area (μm ² ) of the domain (D) using the following formula (1) 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 domain (D) = (maximum diameter of domain (D) ² × π) / (4 × area of domain (D)) ... Formula (1) The thermoplastic resin composition according to claim 1, characterized in that the average aspect ratio of the domain (D) is 1.0 to 2.0. 2. The thermoplastic resin composition according to claim 1, wherein the domain (D) has a domain diameter _D90 divided by a domain diameter _D10 of 1.5 to 25. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin (B) contains an acid-modified thermoplastic elastomer. A recycled carbon fiber reinforced plastic formed from the thermoplastic resin composition according to any one of claims 1 to 4. The present invention comprises recycled carbon fibers (A) and at least two types of thermoplastic resins (B) having different elastic moduli,
A recycled carbon fiber reinforced plastic exhibits an island-in-a-sea structure having domains (D) and a matrix (M) specified by elastic modulus, and satisfies the following (1) to (3):

(1) The average circularity coefficient of the domains (D) calculated from the maximum diameter (μm) and area (μm ² ) of the domains (D) according to the following formula (1) 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) to the matrix (M) is 1:99 to 50:50.

Circularity factor of domain (D)=(maximum diameter of domain (D) ² ×π)/(4×area of domain (D)) (Formula (1)) A method for producing a thermoplastic resin having a different elastic modulus from a recycled carbon fiber (A) by melt-kneading the recycled carbon fiber (A) and at least two kinds of thermoplastic resins (B) having different elastic moduli,
The thermoplastic resin composition has an island-in-a-sea structure having domains (D) and a matrix (M) specified by an elastic modulus, and satisfies the following (1) to (3):
A method for producing a thermoplastic resin composition reinforced with recycled carbon fibers.

(1) The average circularity coefficient of the domains (D) calculated from the maximum diameter (μm) and area (μm ² ) of the domains (D) according to the following formula (1) 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) to the matrix (M) is 1:99 to 50:50.

Circularity factor of domain (D)=(maximum diameter of domain (D) ² ×π)/(4×area of domain (D)) (Formula (1))