JP2018053090A - Resin composition and resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition that makes it possible to obtain a resin molding having excellent impact resistance at low temperature.SOLUTION: A resin composition contains a thermoplastic resin, a carbon fiber, a polyamide, and a compatibilizer with an acid value of 10 mgKOH/g or more and 60 mgKOH/g or less.SELECTED DRAWING: None

Description

  The present invention relates to a resin composition and a resin molded body.

Conventionally, various resin compositions have been provided and used for various applications.
In particular, a resin composition containing a thermoplastic resin is used in parts such as home appliances, various parts of automobiles, casings, office equipment, and casings of electronic and electrical equipment.

  For example, Patent Document 1 discloses that “(a) 0.1 to 90% by weight of at least one polyolefin, (b) 0.1 to 50% by weight of at least one polyamide, (c) 0.1 to 0.1% by weight,” 15% by weight of at least one modified polyolefin, (d) 5.0-75% by weight of at least one reinforcing fiber, (e) 0.1-10% by weight of at least one sulfur-containing additive. A long fiber reinforced polyolefin structure having a length of 3 mm or more is disclosed.

Patent Document 2 discloses that “it has an acid-modified polyolefin (A) block and a polyamide (B) block, carbon derived from an amide group by ¹³ C-NMR, carbon derived from a methyl group, a methylene group, and a methine group” Is a polyolefin resin modifier comprising a polymer (X) having a ratio (α) of 0.5 / 99.5 to 12/88 ”. Furthermore, Patent Document 2 discloses "Inorganic fiber-containing polyolefin resin composition comprising this polyolefin resin modifier (K), polyolefin resin (D) and inorganic fiber (E)." .

Japanese translation of PCT publication No. 2003-528956 JP 2014-181307 A

  An object of the present invention is to provide a resin composition containing a thermoplastic resin, carbon fiber, polyamide, and a compatibilizing agent at a lower temperature than when the acid value of the compatibilizing agent is less than 10 mgKOH / g or more than 60 mgKOH / g. It is providing the resin composition from which the resin molding excellent in impact resistance is obtained.

  The above object is achieved by the present invention described below.

The invention according to claim 1
A thermoplastic resin;
Carbon fiber,
Polyamide,
A compatibilizer having an acid value of 10 mgKOH / g or more and 60 mgKOH / g or less;
A resin composition comprising:

The invention according to claim 2
The polyamide is a structural unit in which a dicarboxylic acid and a diamine are polycondensated, or a structural unit in which a lactam is opened, and includes a structural unit that includes an aromatic ring excluding an aramid structural unit, and a structural unit that does not include an aromatic ring. The resin composition according to claim 1, which is a polyamide having.

The invention according to claim 3
The structural unit containing the aromatic ring is at least one of the following structural units (1) and (2);
The resin composition according to claim 2, wherein the structural unit not containing the aromatic ring is at least one of the following structural units (3) and (4).
Structural unit (1): — (— NH—Ar ¹ —NH—CO—R ¹ —CO —) —
(In the structural unit (1), Ar ¹ represents a divalent organic group containing an aromatic ring. R ¹ represents a divalent organic group containing no aromatic ring.)
Structural unit (2): — (— NH—R ² —NH—CO—Ar ² —CO —) —
(In the structural unit (2), Ar ² represents a divalent organic group containing an aromatic ring. R ² represents a divalent organic group containing no aromatic ring.)
Structural unit (3): — (— NH—R ³¹ —NH—CO—R ³² —CO —) —
(In the structural unit (3), R ³¹ represents a divalent organic group containing no aromatic ring. R ³² represents a divalent organic group containing no aromatic ring.)
Structural unit (4): — (— NH—R ⁴ —CO —) —
(In the structural unit (4), R ⁴ represents a divalent organic group containing no aromatic ring)

The invention according to claim 4
The polyamide according to claim 2 or 3, wherein the polyamide is a copolymerized polyamide obtained by copolymerizing a first polyamide having a structural unit containing the aromatic ring and a second polyamide having a structural unit not containing the aromatic ring. The resin composition as described.

The invention according to claim 5
The resin according to claim 2 or 3, wherein the polyamide is a mixed polyamide containing a first polyamide having a structural unit containing the aromatic ring and a second polyamide having a structural unit not containing the aromatic ring. Composition.

The invention according to claim 6
The resin composition according to any one of claims 2 to 5, wherein a ratio of the aromatic ring of the polyamide is 10% by mass or more and 40% by mass or less.

The invention according to claim 7 provides:
The resin composition according to any one of claims 1 to 6, wherein an average fiber length of the carbon fibers is from 0.1 mm to 5.0 mm.

The invention according to claim 8 provides:
The resin composition according to any one of claims 1 to 7, wherein the thermoplastic resin is a polyolefin.

The invention according to claim 9 is:
The resin composition according to any one of claims 1 to 8, wherein the compatibilizer is a modified polyolefin.

The invention according to claim 10 is:
The resin composition according to any one of claims 1 to 9, wherein a content of the carbon fiber is 0.1 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.

The invention according to claim 11 is:
The resin composition according to any one of claims 1 to 10, wherein a content of the polyamide is 0.1 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.

The invention according to claim 12
The resin composition according to any one of claims 1 to 11, wherein a content of the compatibilizing agent is 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.

The invention according to claim 13 is:
The resin composition according to any one of claims 1 to 12, wherein a content of the polyamide with respect to a mass of the carbon fiber is 1% by mass or more and 200% by mass or less.

The invention according to claim 14 is:
The resin composition according to any one of claims 1 to 13, wherein a content of the compatibilizing agent with respect to a mass of the carbon fiber is 1% by mass or more and 100% by mass or less.

The invention according to claim 15 is:
A thermoplastic resin;
Carbon fiber,
Polyamide,
A compatibilizer having an acid value of 10 mgKOH / g or more and 60 mgKOH / g or less;
Resin molded body containing

The invention according to claim 16 provides:
The polyamide is a structural unit in which a dicarboxylic acid and a diamine are polycondensated, or a structural unit in which a lactam is opened, and includes a structural unit that includes an aromatic ring excluding an aramid structural unit, and a structural unit that does not include an aromatic ring. The resin molded body according to claim 15, which is a polyamide having.

The invention according to claim 17 provides:
The structural unit containing the aromatic ring is at least one of the following structural units (1) and (2);
The resin molded body according to claim 16, wherein the structural unit not containing an aromatic ring is at least one of the following structural units (3) and (4).
Structural unit (1): — (— NH—Ar ¹ —NH—CO—R ¹ —CO —) —
(In the structural unit (1), Ar ¹ represents a divalent organic group containing an aromatic ring. R ¹ represents a divalent organic group containing no aromatic ring.)
Structural unit (2): — (— NH—R ² —NH—CO—Ar ² —CO —) —
(In the structural unit (2), Ar ² represents a divalent organic group containing an aromatic ring. R ² represents a divalent organic group containing no aromatic ring.)
Structural unit (3): — (— NH—R ³¹ —NH—CO—R ³² —CO —) —
(In the structural unit (3), R ³¹ represents a divalent organic group containing no aromatic ring. R ³² represents a divalent organic group containing no aromatic ring.)
Structural unit (4): — (— NH—R ⁴ —CO —) —
(In the structural unit (4), R ⁴ represents a divalent organic group containing no aromatic ring)

The invention according to claim 18
The polyamide according to claim 16 or 17, wherein the polyamide is a copolymerized polyamide obtained by copolymerizing a first polyamide having a structural unit containing the aromatic ring and a second polyamide having a structural unit not containing the aromatic ring. The resin molding as described.

The invention according to claim 19 is
The resin molded body according to claim 16 or 17, wherein the polyamide is a mixed polyamide containing a first polyamide having an aromatic ring and a second polyamide having no aromatic ring.

The invention according to claim 20 provides
The resin molded body according to any one of claims 16 to 19, wherein a ratio of an aromatic ring of the polyamide is 10 mass% or more and 40 mass% or less.

The invention according to claim 21 is
The resin molded body according to any one of claims 15 to 20, wherein an average fiber length of the carbon fibers is 0.1 mm or more and 5.0 mm or less.

The invention according to claim 22 is
The resin molded body according to any one of claims 15 to 21, wherein the thermoplastic resin is a polyolefin.

The invention according to claim 23 is
The resin molded article according to any one of claims 15 to 22, wherein the compatibilizing agent is a modified polyolefin.

The invention according to claim 24 provides
The resin molded body according to any one of claims 15 to 23, wherein a content of the carbon fiber is 0.1 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.

The invention according to claim 25 is
The resin molded body according to any one of claims 15 to 24, wherein a content of the polyamide is 0.1 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.

The invention according to claim 26 provides
The resin molded body according to any one of claims 15 to 25, wherein a content of the compatibilizing agent is 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.

The invention according to claim 27 provides
27. The resin molded body according to any one of claims 15 to 26, wherein a content of the polyamide with respect to a mass of the carbon fiber is 1% by mass or more and 200% by mass or less.

The invention according to claim 28 is
The resin molded body according to any one of claims 15 to 27, wherein a content of the compatibilizing agent with respect to a mass of the carbon fiber is 1% by mass or more and 100% by mass or less.

According to the invention according to claim 1, in the resin composition containing the thermoplastic resin, the carbon fiber, the polyamide, and the compatibilizer, the acid value of the compatibilizer is less than 10 mg KOH / g or more than 60 mg KOH / g. There is provided a resin composition from which a resin molded article excellent in impact resistance at low temperatures can be obtained.
According to the invention according to claim 2, 3, 4 or 5, in the resin composition containing the thermoplastic resin, the carbon fiber, the polyamide, and the compatibilizing agent, when the polyamide contains only the polyamide having no aromatic ring. In comparison, a resin composition from which a resin molded article excellent in impact resistance at low temperatures can be obtained is provided.
According to the invention which concerns on Claim 6, compared with the case where the ratio of the aromatic ring of polyamide is less than 10 mass% or more than 40 mass%, the resin composition from which the resin molding excellent in the impact resistance in low temperature is obtained is obtained. Provided.
According to the invention which concerns on Claim 7, in the resin composition containing a thermoplastic resin, carbon fiber, polyamide, and a compatibilizing agent, compared with the case where the acid value of a compatibilizing agent is less than 10 mgKOH / g or more than 60 mgKOH / g. There is provided a resin composition containing a carbon fiber having an average fiber length of 0.1 mm or more and 5.0 mm or less and capable of obtaining a resin molded article excellent in impact resistance at low temperatures.
According to the invention which concerns on Claim 8, compared with the case where the general purpose resin of an acrylonitrile butadiene styrene copolymer or a styrene polymer is used as a thermoplastic resin, the resin composition from which an inexpensive resin molding is obtained is provided.
According to the invention which concerns on Claim 9, compared with the case where an epoxy copolymer is used as a compatibilizing agent, the resin composition from which the resin molding excellent in the impact resistance in low temperature is obtained is provided.
According to the invention which concerns on Claim 10, compared with the case where content of carbon fiber is less than 0.1 mass part or more than 200 mass parts with respect to 100 mass parts of thermoplastic resins, it was excellent in the impact resistance in low temperature. A resin composition from which a resin molded body can be obtained is provided.
According to the invention of claim 11, the resin is excellent in impact resistance at low temperature as compared with the case where the content of polyamide is less than 0.1 parts by mass or more than 100 parts by mass with respect to 100 parts by mass of the thermoplastic resin. A resin composition from which a molded body can be obtained is provided.
According to the invention which concerns on Claim 12, compared with the case where content of a compatibilizer is less than 1 mass part or more than 50 mass parts with respect to 100 mass parts of thermoplastic resins, resin excellent in impact resistance in low temperature A resin composition from which a molded body can be obtained is provided.
According to the invention of claim 13, a resin molded article having excellent impact resistance at low temperatures can be obtained as compared with the case where the content of the polyamide with respect to the mass of the carbon fiber is less than 1 mass% or more than 200 mass%. A resin composition is provided.
According to the invention which concerns on Claim 14, compared with the case where content of the compatibilizer with respect to the mass of carbon fiber is less than 1 mass% or more than 100 mass%, the resin molding excellent in impact resistance at low temperature is obtained. The resulting resin composition is provided.

According to the invention according to claim 15, in the resin composition containing the thermoplastic resin, the carbon fiber, the polyamide, and the compatibilizer, the acid value of the compatibilizer is less than 10 mg KOH / g or more than 60 mg KOH / g. A resin molded article excellent in impact resistance at low temperatures is provided.
According to the invention according to claim 16, 17, 18, or 19, in the resin molded article containing the thermoplastic resin, the carbon fiber, the polyamide, and the compatibilizing agent, the polyamide contains only a polyamide having no aromatic ring. Compared to the above, a resin molded article excellent in impact resistance at a low temperature is provided.
According to the invention which concerns on Claim 20, compared with the case where the ratio of the aromatic ring of polyamide is less than 10 mass% or more than 40 mass%, the resin molding excellent in the impact resistance in low temperature is provided.
According to the invention according to claim 21, in the resin molded body containing the thermoplastic resin, the carbon fiber, the polyamide, and the compatibilizing agent, the acid value of the compatibilizing agent is less than 10 mg KOH / g or more than 60 mg KOH / g. A resin molded article containing carbon fibers having an average fiber length of 0.1 mm to 5.0 mm and excellent in impact resistance at low temperatures is provided.
According to the twenty-second aspect of the present invention, an inexpensive resin molded body is provided as compared with the case where a general-purpose resin of acrylonitrile butadiene styrene copolymer or styrene polymer is used as the thermoplastic resin.
According to the invention which concerns on Claim 23, compared with the case where an epoxy copolymer is used as a compatibilizing agent, the resin molding excellent in the impact resistance in low temperature is provided.
According to the invention of claim 24, compared with the case where the carbon fiber content is less than 0.1 parts by mass or more than 200 parts by mass with respect to 100 parts by mass of the thermoplastic resin, the impact resistance at low temperature is excellent. A resin molded body is provided.
According to the invention of claim 25, a resin having excellent impact resistance at low temperatures as compared with the case where the polyamide content is less than 0.1 parts by mass or more than 100 parts by mass with respect to 100 parts by mass of the thermoplastic resin. A shaped body is provided.
According to the invention of claim 26, the resin having excellent impact resistance at low temperature as compared with the case where the content of the compatibilizer is less than 1 part by mass or more than 50 parts by mass with respect to 100 parts by mass of the thermoplastic resin. A shaped body is provided.
According to the invention of claim 27, there is provided a resin molded article excellent in impact resistance at low temperature as compared with the case where the polyamide content relative to the mass of the carbon fiber is less than 1 mass% or more than 200 mass%. The
According to the invention of claim 28, there is provided a resin molded article excellent in impact resistance at low temperature as compared with the case where the content of the compatibilizer with respect to the mass of the carbon fiber is less than 1 mass% or more than 100 mass%. Provided.

It is a model figure which shows the principal part of the resin molding which concerns on this embodiment. It is a schematic diagram for demonstrating an example of the principal part of the resin molding which concerns on this embodiment. It is a schematic diagram of the test using a micro droplet method.

  Hereinafter, an embodiment as an example of the resin composition and the resin molded body of the present invention will be described.

[Resin composition]
The resin composition according to the present embodiment includes a thermoplastic resin, carbon fiber, polyamide, and a compatibilizing agent having an acid value of 10 mgKOH / g or more and 60 mgKOH / g or less.

In recent years, in order to obtain a resin molded article excellent in mechanical strength, a resin composition containing a thermoplastic resin as a base material (matrix) and reinforcing fibers has been used.
In such a resin composition, if the affinity between the reinforcing fiber and the thermoplastic resin is low, a space is formed at the interface between the two, and the adhesion at the interface may be reduced.
In particular, when carbon fibers are used as reinforcing fibers in the resin composition, higher mechanical strength is required compared to glass fibers, etc., but this contributes to adhesion with thermoplastic resins such as hydroxyl groups and carboxyl groups on the surface of carbon fibers. Since there are few polar groups to perform compared with glass fiber, the adhesiveness in the interface of carbon fiber and a thermoplastic resin falls. As a result, mechanical strength, particularly impact resistance at a low temperature (for example, −20 ° C. or lower) is hardly increased compared to the blending of carbon fibers. In particular, when repeated impact is applied at a low temperature, the peeling at the interface between the carbon fiber and the thermoplastic resin is likely to proceed, and the impact resistance tends to decrease greatly from the beginning.

Therefore, the resin composition according to the present embodiment includes four components: a thermoplastic resin, carbon fiber, polyamide, and a compatibilizer having an acid value of 10 mgKOH / g to 60 mgKOH / g.
By setting it as this structure, the resin molding excellent in the impact resistance in low temperature (for example, -30 degrees C or less) is obtained. Although it is not clear about the operation | movement from which such an effect is acquired, it estimates as follows.

When the resin composition is obtained from the resin composition according to the present embodiment, when the resin composition is hot melt mixed, the thermoplastic resin as a base material and the compatibilizer are melted, and the intramolecular content of the compatibilizer Both of them are compatible with each other by the amide bond contained in the polyamide molecule, and the polyamide is dispersed in the resin composition.
In this state, when the polyamide comes into contact with the carbon fiber, an amide bond contained in a large number along the molecular chain of the polyamide and a slight polar group present on the surface of the carbon fiber have an affinity (attraction and hydrogen bond). To physically bond at multiple locations. Further, since the thermoplastic resin and the polyamide are generally poorly compatible, the repulsive force between the thermoplastic resin and the polyamide increases the frequency of contact between the polyamide and the carbon fiber. Increases the amount and area of adhesion. Thus, a coating layer made of polyamide is formed around the carbon fibers (see FIG. 1). In FIG. 1, PP indicates a thermoplastic resin, CF indicates a carbon fiber, and CL indicates a coating layer.
The polyamide forming the coating layer is also compatible with some reactive groups in the molecule of the compatibilizer by chemical reaction and electrostatic interaction between polar groups. By being compatible with the plastic resin, the attractive force and the repulsive force are in an equilibrium state, and the polyamide coating layer is formed in a thin and nearly uniform state. In particular, since the affinity between the carboxy group present on the surface of the carbon fiber and the amide bond contained in the polyamide molecule is high, a coating layer made of polyamide is easily formed around the carbon fiber, making it thin and uniform. It is considered to be an excellent coating layer.

  In addition, although it is preferable that the coating layer has coat | covered the whole circumference | surroundings of carbon fiber, there may be a part which is not covered partially.

On the other hand, when a compatibilizer having a high acid value in the above range is applied as the compatibilizer, the free polyamide is finely dispersed in the thermoplastic resin without contributing to the formation of the coating layer. This is because if the acid value of the compatibilizing agent is within the above range, the reactivity between the polyamide and the compatibilizing agent is increased, and it is considered that compatibilization is promoted.
If the polyamide is finely dispersed in the thermoplastic resin, mechanical strength, particularly impact resistance at low temperatures, is improved. This is because 1) the polyamide domain dispersed in the thermoplastic resin plays a role of dispersing mechanical loads such as impacts, and 2) the polyamide domain is fine, and therefore the interface between the polyamide domain and the thermoplastic resin. This is because it is considered that the stress concentration is relaxed.

  From the above, the resin composition according to the present embodiment has increased adhesion at the interface between the carbon fiber and the thermoplastic resin, and the polyamide is finely dispersed in the thermoplastic resin. In particular, it is presumed that a resin molded article excellent in impact resistance at a low temperature can be obtained. Moreover, it is estimated that the resin molding which was excellent in the bending elastic modulus is obtained for the same reason.

  Here, the resin composition according to the present embodiment and the resin molded body obtained thereby are coated with polyamide around the carbon fiber by hot melt kneading and injection molding at the time of manufacturing the resin composition (for example, pellets). A layer is formed, and the thickness of the coating layer is preferably 5 nm to 700 nm.

  In the resin composition according to this embodiment, the thickness of the coating layer made of polyamide is 5 nm or more and 700 nm or less, and is preferably 10 nm or more and 650 nm or less from the viewpoint of further improving impact resistance at low temperatures. When the thickness of the coating layer is 10 nm or more, impact resistance at low temperature is improved, and when the thickness of the coating layer is 700 nm or less, the interface between the carbon fiber and the thermoplastic resin via the coating layer becomes brittle. And lowering of impact resistance at low temperatures is suppressed.

The thickness of the coating layer is a value measured by the following method. The measurement object is broken in liquid nitrogen, and the cross section is observed using an electron microscope (VE-9800 manufactured by Keyence). In the cross section, 100 thicknesses of the coating layer covering the carbon fiber are measured and calculated as an average value.
In addition, confirmation of a coating layer is implemented by the said cross-sectional observation.

  In the resin composition according to the present embodiment and the resin molded body obtained thereby, the domain diameter of the polyamide in the thermoplastic resin thermoplastic resin is 0.1 μm from the viewpoint of further improving impact resistance at low temperatures. The thickness is preferably 10 μm or less, and more preferably 0.5 μm or more and 5 μm or less.

The domain diameter of the polyamide is a value measured by the following method.
That is, a sample piece of a measurement object is embedded in an epoxy resin, and a precision polished cross section is prepared with an automatic polishing machine (Vector made by BUEHLER).
Next, using a SEM (Hitachi S-3400N, acceleration voltage 15 KV), a sample of the polished cross section of the sample piece was randomly photographed at three magnifications at 1500 times, and image analysis software (ImageProPlus) was used to obtain a polyamide carbon fiber. The luminance range is set so that all the coating layer components and free components (corresponding to the polyamide domain) are extracted.
Then, the coating layer components are manually selected and excluded, and only the free component (corresponding to the polyamide domain) is selected as the measurement item, the diameter and the number of objects are selected and calculated, and the size of each domain (diameter = equivalent circle diameter) And the number is obtained, and from this, the average value of the size (diameter) of the domain is obtained.

In addition, in the resin composition (and its resin molding) which concerns on this embodiment, the structure which a compatibilizing agent partially dissolves between this coating layer and a thermoplastic resin, for example is taken.
Specifically, for example, a compatibilizer layer may be interposed between the polyamide coating layer and the base thermoplastic resin (see FIG. 2). That is, it is preferable that a layer of a compatibilizing agent is formed on the surface of the coating layer, and the coating layer and the thermoplastic resin are adjacent to each other through the layer of the compatibilizing agent. The compatibilizing agent layer is formed thinner than the coating layer, but the interposition of the compatibilizing agent layer increases the adhesion (adhesiveness) between the covering layer and the thermoplastic resin, and the mechanical strength, particularly at low temperatures. It becomes easy to obtain a resin molded article excellent in impact resistance. In FIG. 2, PP indicates a thermoplastic resin, CF indicates a carbon fiber, CL indicates a coating layer, and CA indicates a layer of a compatibilizing agent.

In particular, the compatibilizer layer is bonded to the coating layer (hydrogen bond, covalent bond by reaction of the functional group of the compatibilizer and polyamide, etc.) and is compatible with the thermoplastic resin, It is good to interpose between thermoplastic resins. This configuration includes, for example, the same structure as the thermoplastic resin as the base material or a compatible structure as a compatibilizing agent, and a part that reacts with the functional group of the polyamide described above in a part of the molecule. It is easy to realize when a compatibilizer is applied.
Specifically, for example, when polyolefin, polyamide as a thermoplastic resin, and maleic anhydride modified polyolefin as a compatibilizer are applied, the maleic anhydride modified polyolefin layer (compatibility agent layer) is the maleic anhydride. It is preferable that the carboxy group generated by ring opening of the site reacts and bonds with the amine residue of the polyamide layer (coating layer), and the polyolefin site is present in a state of being compatible with the polyolefin.

Here, the method for confirming that the compatibilizing agent layer is interposed between the coating layer and the thermoplastic resin is as follows.
An infrared spectroscopic analyzer (NICOLET6700FT-IR manufactured by Thermo Fisher) is used as the analyzer. For example, in the case of a resin composition (or resin molding) of polypropylene (hereinafter referred to as PP) as a thermoplastic resin, PA66 as polyamide and maleic acid-modified polypropylene (hereinafter referred to as MA-PP) as a modified polyolefin, a mixture thereof, PP and PA66, IR spectra of PP mixture, PP-MA-PP mixture, PP alone, PA66 alone, and MA-PP alone are obtained by the KBr tablet method, and the acid anhydride origin in the mixture (a peak characteristic of MA-PP) ) comparing the peak areas of the wave number 1820 cm ^-1 or 1750 cm ^-1 or less in the range of analysis. In a mixture of PP, PA66, and MA-PP, a decrease in the acid anhydride peak area is confirmed, and it is confirmed that MA-PP and PA66 are reacting. Thereby, it can confirm that the layer (bonding layer) of a compatibilizer exists between the coating layer and the thermoplastic resin. Specifically, when MA-PP and PA66 are reacted, the cyclic maleated portion of MA-PP is opened, and the amine residue of PA66 is chemically bonded to reduce the cyclic maleated portion. It can be confirmed that a layer (bonding layer) of a compatibilizer is interposed between the resin and the thermoplastic resin.

  Hereinafter, the detail of each component of the resin composition which concerns on this embodiment is demonstrated.

-Thermoplastic resin (A)-
A thermoplastic resin is a base material of a resin composition and refers to a resin component reinforced with carbon fibers (also referred to as a matrix resin).
The thermoplastic resin is not particularly limited. For example, polyolefin (PO), polyphenylene sulfide (PPS), polyamide (PA), polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), Polyetheretherketone (PEEK), Polyethersulfone (PES), Polyphenylsulfone (PPSU), Polysulfone (PSF), Polyethylene terephthalate (PET), Polybutylene terephthalate (PBT), Polyacetal (POM), Polycarbonate (PC) ), Polyvinylidene fluoride (PVDF), acrylonitrile butadiene styrene copolymer (ABS), acrylonitrile styrene (AS), and the like.
A thermoplastic resin may be used individually by 1 type, and may use 2 or more types together.

Among these, polyolefin (PO) is preferable from the viewpoint of further improvement in impact resistance at low temperature and cost.
The polyolefin is a resin containing a repeating unit derived from an olefin, and may contain a repeating unit derived from a monomer other than the olefin as long as it is 30% by mass or less based on the whole resin.
Polyolefin is obtained by addition polymerization of olefin (a monomer other than olefin, if necessary).
Moreover, 1 type may be sufficient as the monomer other than an olefin and olefin for obtaining polyolefin, respectively, and 2 or more types may be sufficient as it.
The polyolefin may be a copolymer or a homopolymer. The polyolefin may be linear or branched.

Here, examples of the olefin include linear or branched aliphatic olefins and alicyclic olefins.
Examples of the aliphatic olefin include α-olefins such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-hexadecene and 1-octadecene.
Examples of the alicyclic olefin include cyclopentene, cycloheptene, norbornene, 5-methyl-2-norbornene, tetracyclododecene, vinylcyclohexane and the like.
Among these, from the viewpoint of cost, α-olefin is preferable, ethylene and propylene are more preferable, and propylene is particularly preferable.

The monomer other than olefin is selected from known addition polymerizable compounds.
Examples of the addition polymerizable compound include styrenes such as styrene, methylstyrene, α-methylstyrene, β-methylstyrene, t-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid or a salt thereof; (Meth) acrylic acid esters such as alkyl (meth) acrylate, benzyl (meth) acrylate and dimethylaminoethyl (meth) acrylate; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as vinyl methyl ether; vinylidene halides such as vinylidene chloride; N-vinyl compounds such as N-vinylpyrrolidone; and the like.

Suitable polyolefins include polypropylene (PP), polyethylene (PE), polybutene, polyisobutylene, coumarone / indene resin, terpene resin, ethylene / vinyl acetate copolymer resin (EVA), and the like.
Especially, it is preferable that it is resin containing only the repeating unit derived from an olefin, and a polypropylene is especially preferable from the point of cost.

The molecular weight of the thermoplastic resin is not particularly limited, and may be determined according to the type of resin, molding conditions, the resin molding, and the like. For example, if the thermoplastic resin is polyolefin, the weight average molecular weight (Mw) is preferably in the range of 10,000 to 300,000, and more preferably in the range of 10,000 to 200,000.
Further, the glass transition temperature (Tg) or melting point (Tm) of the thermoplastic resin is not particularly limited as in the case of the molecular weight, and may be determined according to the type of resin, molding conditions, use of the resin molding, and the like. For example, if the thermoplastic resin is polyolefin, the melting point (Tm) thereof is preferably in the range of 100 ° C. or higher and 300 ° C. or lower, and more preferably in the range of 150 ° C. or higher and 250 ° C. or lower.

In addition, the weight average molecular weight (Mw) and melting | fusing point (Tm) of polyolefin show the value measured as follows.
That is, the weight average molecular weight (Mw) of the polyolefin is measured by gel permeation chromatography (GPC) under the following conditions. A high temperature GPC system “HLC-8321GPC / HT” is used as the GPC apparatus, and o-dichlorobenzene is used as the eluent. The polyolefin is once melted and filtered into o-dichlorobenzene at a high temperature (temperature of 140 ° C. to 150 ° C.), and the filtrate is used as a measurement sample. The measurement conditions were a sample concentration of 0.5% and a flow rate of 0.6 ml / min. Sample injection volume 10 μl, using RI detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-”. It is created from 10 samples of “2,500”, “F-4”, “F-40”, “F-128”, and “F-700”.
In addition, the melting point (Tm) of the polyolefin is calculated from the DSC curve obtained by differential scanning calorimetry (DSC) according to the “melting peak” described in the method for determining the melting temperature in JIS K 7121-1987 “Method for measuring plastic transition temperature”. Calculated by “temperature”.

The content of the thermoplastic resin may be determined according to the use of the resin molded body, but is preferably 5% by mass or more and 95% by mass or less, and preferably 10% by mass with respect to the total mass of the resin composition. It is more preferably 95% by mass or less, and further preferably 20% by mass or more and 95% by mass or less.
In addition, when using polyolefin as a thermoplastic resin, it is preferable to make 20 mass% or more into polyolefin with respect to the total mass of a thermoplastic resin.

-Carbon fiber-
Known carbon fibers are used as the carbon fibers, and both PAN-based carbon fibers and pitch-based carbon fibers are used.

The carbon fiber may be subjected to a known surface treatment.
Examples of the surface treatment of the carbon fiber include an oxidation treatment and a sizing treatment.
The form of the carbon fiber is not particularly limited, and may be selected according to the use of the resin molded body. Examples of the form of the carbon fiber include a fiber bundle composed of a large number of single fibers, a bundle of fiber bundles, a woven fabric in which fibers are woven in two dimensions or three dimensions, and the like.

The fiber diameter, fiber length, and the like of the carbon fiber are not particularly limited, and may be selected according to the use of the resin molded body.
However, even if the fiber length of the carbon fiber is short, a resin molded article having excellent impact resistance at low temperatures can be obtained. Therefore, the average fiber length of the carbon fiber is 0.1 mm or more and 5.0 mm or less (preferably 0.00. 2 mm or more and 2.0 mm or less).
Further, the average diameter of the carbon fibers may be, for example, 5.0 μm or more and 10.0 μm or less (preferably 6.0 μm or more and 8.0 μm or less).

Here, the measuring method of the average fiber length of carbon fibers is as follows. The carbon fiber is observed with an optical microscope at a magnification of 100, and the length of the carbon fiber is measured. And this measurement is performed about 200 carbon fibers, and let the average value be the average fiber length of carbon fibers.
On the other hand, the measuring method of the average diameter of carbon fiber is as follows. A cross section perpendicular to the length direction of the carbon fiber is observed with a SEM (scanning electron microscope) at a magnification of 1000 times, and the diameter of the carbon fiber is measured. And this measurement is performed about 100 carbon fibers, and let the average value be an average diameter of carbon fiber.

In addition, when the fiber length of carbon fiber becomes short, there exists a tendency for the resin reinforcement | strengthening ability of carbon fiber to fall. In particular, due to recent demands for recycling, it has also been promoted to pulverize and reuse a resin molded body reinforced with carbon fiber, and the fiber length of the carbon fiber is often shortened when the resin molded body is pulverized. . Moreover, the fiber length of carbon fiber may become short at the time of the hot-melt kneading | mixing at the time of manufacturing a resin composition. For this reason, when a resin molded body is molded from a resin composition containing carbon fibers having a reduced fiber length, the mechanical strength, particularly the impact resistance at low temperatures, tends to decrease.
However, even if a resin molded body containing carbon fibers is pulverized and a recycled product in which carbon fibers are shortened is used as a raw material, or carbon fibers are shortened during hot melt kneading, the resin composition according to the present embodiment The product is useful because a resin molded article excellent in impact resistance at a low temperature can be obtained.

Commercially available products may be used as the carbon fiber.
Commercially available PAN-based carbon fibers include “Torayca (registered trademark)” manufactured by Toray Industries, Inc., “Tenax” manufactured by Toho Tenax Co., Ltd., and “Pyrofil (registered trademark)” manufactured by Mitsubishi Rayon Co., Ltd. Is mentioned. In addition, examples of commercially available PAN-based carbon fibers include commercially available products manufactured by Hexcel, Cytec, Dow-Aksa, Taiwan Plastic, and SGL.
Examples of commercially available pitch-based carbon fibers include “Dialyad (registered trademark)” manufactured by Mitsubishi Rayon Co., Ltd., “GRANOC” manufactured by Nippon Graphite Fiber Co., Ltd., and “Kureka” manufactured by Kureha Co., Ltd. . In addition, examples of commercially available pitch-based carbon fibers include those manufactured by Osaka Gas Chemical Co., Ltd. and those manufactured by Cytec.

  In addition, carbon fiber may be used individually by 1 type, and may use 2 or more types together.

The carbon fiber content is preferably 0.1 parts by mass or more and 200 parts by mass or less, more preferably 1 part by mass or more and 180 parts by mass or less, and more preferably 5 parts by mass or more and 150 parts by mass with respect to 100 parts by mass of the thermoplastic resin. It is still more preferable that it is below mass parts.
The carbon fiber is contained in an amount of 0.1 parts by mass or more with respect to 100 parts by mass of the thermoplastic resin, so that the resin composition is reinforced, and the carbon fiber content is 200 parts by mass with respect to 100 parts by mass of the thermoplastic resin. By setting it as the part or less, the moldability at the time of obtaining a resin molding becomes favorable.
In addition, when using reinforced fiber other than carbon fiber, it is preferable to make 80 mass% or more into carbon fiber with respect to the total mass of a reinforced fiber.

Hereafter, the content (parts by mass) with respect to 100 parts by mass of the thermoplastic resin may be abbreviated as “phr (per hindered resin)”.
When this abbreviation is used, the carbon fiber content is 0.1 phr or more and 200 phr or less.

-Polyamide-
Examples of the polyamide include polyamides obtained by cocondensation polymerization of dicarboxylic acid and diamine, polyamides obtained by ring-opening polycondensation of lactam, and polyamides obtained by condensing dicarboxylic acid, diamine and lactam. That is, examples of the polyamide include polyamides having at least one of a structural unit obtained by polycondensation of a dicarboxylic acid and a diamine and a structural unit obtained by ring opening of a lactam.

  Polyamide is a structural unit in which a dicarboxylic acid and a diamine are polycondensated, or a structural unit in which a lactam is opened, and has a structural unit containing an aromatic ring excluding aramid, and a polyamide having a structural unit not containing an aromatic ring Any of polyamides having a structural unit containing an aromatic ring excluding an aramid structural unit and a structural unit not containing an aromatic ring may be used, but from the viewpoint of improving impact resistance at low temperatures, an aromatic excluding an aramid structural unit A polyamide having a structural unit containing a ring and a structural unit not containing an aromatic ring is preferred.

  In particular, when a polyamide having a structural unit including an aromatic ring excluding an aramid structural unit and a structural unit not including an aromatic ring is applied as the polyamide, both the affinity between the carbon fiber and the thermoplastic resin is improved. Here, a polyamide having only a structural unit containing an aromatic ring tends to have a higher affinity for carbon fibers and a lower affinity for a thermoplastic resin than a polyamide having only a structural unit not containing an aromatic ring. A polyamide having only a structural unit containing no aromatic ring tends to have a lower affinity for carbon fibers and a higher affinity for a thermoplastic resin than a polyamide having only a structural unit containing an aromatic ring. Therefore, by applying a polyamide having both structural units, the affinity between the carbon fiber and the thermoplastic resin is improved, and the adhesion of the interface between the carbon fiber and the thermoplastic resin is further enhanced by the polyamide coating layer. become. Therefore, it becomes easy to obtain a resin molded article having excellent mechanical strength, particularly impact resistance at low temperatures.

Further, when a polyamide having a structural unit containing an aromatic ring excluding an aramid structural unit and a structural unit not containing an aromatic ring is applied as the polyamide, the melt viscosity is lowered and moldability (for example, injection moldability) is also improved. Therefore, it becomes easy to obtain a resin molded body with high appearance quality.
When a polyamide having only an aramid structural unit is applied as the polyamide, the thermoplastic resin is thermally deteriorated at a high temperature at which the polyamide can be melted. Further, at a temperature that causes thermal degradation of the thermoplastic resin, the polyamide cannot be sufficiently melted, the moldability (for example, injection moldability) is deteriorated, and the appearance quality and mechanical performance of the resulting resin molded body are deteriorated.

The aromatic ring refers to a 5-membered or more monocyclic aromatic ring (cyclopentadiene, benzene) and a condensed ring (naphthalene or the like) in which a plurality of 5-membered or more monocyclic aromatic rings are condensed. Aromatic rings also include heterocycles (such as pyridine rings).
The aramid structural unit refers to a structural unit obtained by a condensation polymerization reaction between a dicarboxylic acid containing an aromatic ring and a diamine containing an aromatic ring.

Here, examples of the structural unit containing an aromatic ring excluding the aramid structural unit include at least one of the following structural units (1) and (2).
Structural unit (1): — (— NH—Ar ¹ —NH—CO—R ¹ —CO —) —
(In the structural unit (1), Ar ¹ represents a divalent organic group containing an aromatic ring. R ¹ represents a divalent organic group containing no aromatic ring.)
Structural unit (2): — (— NH—R ² —NH—CO—Ar ² —CO —) —
(In the structural unit (2), Ar ² represents a divalent organic group containing an aromatic ring. R ² represents a divalent organic group containing no aromatic ring.)

On the other hand, examples of the structural unit not containing an aromatic ring include at least one of the following structural units (3) and (4).
Structural unit (3): — (— NH—R ³¹ —NH—CO—R ³² —CO —) —
(In the structural unit (3), R ³¹ represents a divalent organic group containing no aromatic ring. R ³² represents a divalent organic group containing no aromatic ring.)
Structural unit (4): — (— NH—R ⁴ —CO —) —
(In the structural unit (4), R ⁴ represents a divalent organic group containing no aromatic ring)

In Structural Formulas (1) to (3), the “divalent organic group” indicated by each symbol is an organic group derived from a divalent organic group possessed by dicarboxylic acid, diamine, or lactam. Specifically, for example, in the structural unit (1), “a divalent organic group containing an aromatic ring” represented by Ar ¹ represents a residue obtained by removing two amino groups from a diamine, and R ¹ represents “ The “divalent organic group not containing an aromatic ring” indicates a residue obtained by removing two carboxy groups from a dicarboxylic acid. Further, for example, in the structural unit (4), the “divalent organic group not containing an aromatic ring” represented by R ⁴ is sandwiched between the “NH group” and the “CO group” when the lactam is opened. An organic group is shown.

  Examples of the polyamide include copolymer polyamide and mixed polyamide. As the polyamide, a copolyamide and a mixed polyamide may be used in combination. Among these, as the polyamide, a mixed polyamide is preferable from the viewpoint of further improving impact resistance at low temperatures.

The copolymerized polyamide is, for example, a copolymerized polyamide obtained by copolymerizing a first polyamide having a structural unit including an aromatic ring excluding an aramid structural unit and a second polyamide having a structural unit not including an aromatic ring.
The mixed polyamide is, for example, a mixed polyamide including a first polyamide having an aromatic ring and a second polyamide having no aromatic ring.
Hereinafter, for convenience, the first polyamide may be referred to as “aromatic polyamide” and the second polyamide may be referred to as “aliphatic polyamide”.

In the copolymerized polyamide, the ratio of aromatic polyamide to aliphatic polyamide (aromatic polyamide / aliphatic polyamide) is 20/80 to 99/1 in terms of mass ratio from the viewpoint of further improving impact resistance at low temperatures. The following (preferably 50/50 or more and 96/4 or less) is good.
On the other hand, in the mixed polyamide, the ratio of the aromatic polyamide to the aliphatic polyamide (aromatic polyamide / aliphatic polyamide) is 20/80 or more in terms of mass ratio from the viewpoint of further improving impact resistance at low temperatures. 1 or less (preferably 50/50 or more and 96/4 or less) is good.

In the aromatic polyamide, the proportion of the structural unit containing an aromatic ring is preferably 80% by mass or more (preferably 90% by mass or more, more preferably 100% by mass or more) with respect to all the structural units.
On the other hand, in the aliphatic polyamide, the proportion of structural units not containing an aromatic ring is preferably 80% by mass or more (preferably 90% by mass or more, more preferably 100% by mass or more) with respect to all structural units.

  Examples of the aromatic polyamide include a condensation polymer of a dicarboxylic acid containing an aromatic ring and a diamine not containing an aromatic ring, a condensation polymer of a dicarboxylic acid not containing an aromatic ring and a diamine containing an aromatic ring, and the like.

  Examples of the aliphatic polyamide include a condensation polymer of a dicarboxylic acid not containing an aromatic ring and a diamine not containing an aromatic ring, and a ring-opening polycondensation product of a lactam not containing an aromatic ring.

Here, examples of the dicarboxylic acid containing an aromatic ring include phthalic acid (terephthalic acid, isophthalic acid, etc.), biphenyl dicarboxylic acid, and the like.
Examples of the dicarboxylic acid not containing an aromatic ring include oxalic acid, adipic acid, suberic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, azelaic acid and the like.
Examples of the diamine containing an aromatic ring include p-phenylenediamine, m-phenylenediamine, m-xylenediamine, diaminodiphenylmethane, and diaminodiphenyl ether.
Examples of the diamine not containing an aromatic ring include ethylene diamine, pentamethylene diamine, hexamethylene diamine, nonane diamine, decamethylene diamine, and 1,4-cyclohexane diamine.

  Examples of lactams that do not contain an aromatic ring include ε-caprolactam, undecane lactam, lauryl lactam, and the like.

  In addition, each dicarboxylic acid, each diamine, and each lactam may be used individually by 1 type, and may be used together 2 or more types.

As aromatic polyamides, MXD6 (condensation polymer of adipic acid and metaxylenediamine), nylon 6T (condensation polymer of terephthalic acid and hexamethylenediamine), nylon 6I (polycondensation of isophthalic acid and hexamethylenediamine) Body), nylon 9T (polycondensate of terephthalic acid and nandiamine), nylon M5T (polycondensate of terephthalic acid and methylpentadiamine), and the like.
Commercially available aromatic polyamides include “MXD6” manufactured by Mitsubishi Gas Chemical Company, “GENESTAR (registered trademark): PA6T” manufactured by Kuraray Co., Ltd., “GENESTAR (registered trademark): PA9T” manufactured by Kuraray Co., Ltd., and “TY-” manufactured by Toyobo Co., Ltd. 502NZ: PA6T "etc. are illustrated.

Examples of aliphatic polyamides include nylon 6 (ring-opening polycondensate of ε-caprolactam), nylon 11 (ring-opening polycondensate of undecane lactam), nylon 12 (ring-opening polycondensate of lauryl lactam), nylon 66 (adipine) Examples thereof include a condensation polymer of acid and hexamethylene diamine) and nylon 610 (condensation polymer of sebacic acid and hexamethylene diamine).
Commercially available products of aliphatic polyamides include “Zytel (registered trademark): 7331J (PA6)” manufactured by Dupont, and “Zytel (registered trademark): 101L (PA66)” manufactured by Dupont.

The physical properties of polyamide will be described.
The proportion of the aromatic ring of the polyamide (copolymerized polyamide, mixed polyamide) is preferably 1% by mass or more and 55% by mass or less, and more preferably 5% by mass or more and 50% by mass or less, from the viewpoint of further improving impact resistance at low temperatures. More preferably, 10 mass% or more and 40 mass% or less are more preferable.
The ratio of the aromatic ring of the mixed polyamide is the ratio of the aromatic ring to the whole of the aromatic polyamide and the aliphatic polyamide.

  Here, the ratio of the aromatic ring of the polyamide means the total ratio of “monocyclic aromatic ring, condensed ring obtained by condensing a single aromatic ring” contained in the polyamide. In the calculation of the ratio of the aromatic ring of the polyamide, a substituent substituted with a monocyclic aromatic ring or a condensed ring condensed with a single aromatic ring is excluded.

  That is, the ratio of the aromatic ring of the polyamide is determined from the molecular weight of the “structural unit in which the dicarboxylic acid and the diamine are polycondensed” or “the structural unit in which the lactam is opened”. When it has a substituent, it calculates with the ratio (mass%) of the molecular weight of the aromatic ring except a substituent.

First, the ratio of the aromatic ring of a typical polyamide is shown below. The ratios of the aromatic rings of nylon 6 and nylon 66 not having an aromatic ring are both 0% by mass. On the other hand, MXD6 having an aromatic ring has an aromatic ring “—C ₆ H ₄ — (molecular weight 76.10)” in the structural unit, and therefore the ratio of the aromatic ring is 30.9% by mass. Similarly, the ratio of the aromatic ring of nylon 9T is 26.49% by mass.

Nylon 6: Structural unit structure “—NH— (CH ₂ ) ₅ —CO—”, structural unit molecular weight = 113.16, ratio of aromatic ring = 0 mass%
Nylon 66: Structural unit structure “—NH— (CH ₂ ) ₆ —NH—CO— (CH ₂ ) ₄ —CO—”, molecular weight of structural unit = 226.32, ratio of aromatic ring = 0% by mass
MXD6: Structural unit structure “—NH—CH ₂ —C ₆ H ₄ —CH ₂ —NH—CO— (CH ₂ ) ₄ —CO—”, structural unit molecular weight = 246.34, aromatic ring ratio = 30.9% by mass
Nylon 9T: Structural unit structure “—NH— (CH ₂ ) ₉ —NH—CO—C ₆ H ₄ —CO—”, molecular weight of structural unit = 288.43, ratio of aromatic ring = 26.4% by mass

  And the ratio of the aromatic ring of copolymer polyamide and mixed polyamide is calculated | required as follows.

-Example 1: Nylon 6 and MXD6 copolymer polyamide or mixed polyamide (mass ratio of nylon 6 and MXD6 = 50/50)-
Ratio of aromatic ring = (ratio of nylon 6 × ratio of aromatic ring in nylon 6) + ratio of MXD6 × ratio of aromatic ring in MXD6) = (0.5 × 0) + (0.5 × 30.9) = 15.5 (mass%)

-Example 2: Copolymer polyamide or mixed polyamide of nylon 66, MXD6 and nylon 9T (mass ratio of nylon 66, MXD6 and nylon 9T = 50/25/25)-
Ratio of aromatic ring = (ratio of nylon 66 × ratio of aromatic ring in nylon 66) + ratio of MXD6 × ratio of aromatic ring in MXD6 + (ratio of nylon 9T × ratio of aromatic ring in nylon 9T) = ( 0.5 × 0.5 × 0) + (0.25 × 30.9) + (0.25 × 26.4) = 14.3 (mass%)

The molecular weight of the polyamide (copolymerized polyamide, mixed polyamide) is not particularly limited as long as it is easier to melt than the thermoplastic resin coexisting in the resin composition. For example, the weight average molecular weight of polyamide is preferably in the range of 10,000 to 300,000, and more preferably in the range of 10,000 to 100,000.
Further, the glass transition temperature or melting temperature (melting point) of polyamide (copolyamide, mixed polyamide) is not particularly limited as in the case of the molecular weight described above, and is higher than that of the thermoplastic resin coexisting in the resin composition. It should be easy. For example, the melting point (Tm) of polyamide (copolyamide, mixed polyamide) is preferably in the range of 100 ° C. or higher and 400 ° C. or lower, and more preferably in the range of 150 ° C. or higher and 300 ° C. or lower.

Polyamide (polyamides of copolymerized polyamide and mixed polyamide) is preferably a resin having low compatibility with a thermoplastic resin, specifically, a resin having a solubility parameter (SP value) different from that of a thermoplastic resin.
Here, the difference in SP value between the thermoplastic resin and the polyamide is preferably 3 or more and more preferably 3 or more and 6 or less from the viewpoint of compatibility between the two and repulsive force between the two.
The SP value here is a value calculated by Fedor's method. Specifically, the solubility parameter (SP value) is, for example, Polym. Eng. Sci. , Vol. 14, p. 147 (1974), the SP value is calculated by the following formula.
Formula: SP value = √ (Ev / v) = √ (ΣΔei / ΣΔvi)
(Where Ev: evaporation energy (cal / mol), v: molar volume (cm ³ / mol), Δei: evaporation energy of each atom or atomic group, Δvi: molar volume of each atom or atomic group)
The solubility parameter (SP value) employs (cal / cm ³ ) ^1/2 as a unit, but the unit is omitted in accordance with common practice and expressed in a dimensionless manner.

The content of the polyamide is preferably 0.1 parts by mass or more and 100 parts by mass or less, more preferably 30 parts by mass or more and 90 parts by mass with respect to 100 parts by mass of the thermoplastic resin, from the viewpoint of further improving impact resistance at low temperatures. More preferably, it is more preferably 40 parts by weight or more and 80 parts by weight or less.
When the content of the polyamide is in the above range, the affinity with the carbon fiber is increased, and the impact resistance at low temperatures is improved.

The content of the polyamide is preferably proportional to the content of the carbon fiber described above from the viewpoint of effectively expressing the affinity with the carbon fiber.
The polyamide content relative to the mass of the carbon fiber is preferably 1% by mass or more and 200% by mass or less, more preferably 10% by mass or more and 150% by mass or less, and more preferably 12% by mass or more and 120% by mass or less. More preferably it is.
When the content of the polyamide with respect to the mass of the carbon fiber is 1% by mass or more, the affinity between the carbon fiber and the polyamide is easily increased, and when it is 200% by mass or less, the resin fluidity is improved.

Here, the adhesion between polyamide and carbon fiber is evaluated by an index such as interfacial shear strength.
Interfacial shear strength is measured using the microdroplet method. Here, the microdroplet method will be described with reference to the schematic diagram of the test shown in FIG.
The microdroplet method applies a liquid resin to a single fiber f, attaches a droplet D (also referred to as a resin grain or resin ball), fixes the droplet D, and then pulls out the single fiber f in the direction of the arrow. This is a method for evaluating the interfacial adhesion between the two.
Based on this test, the interfacial shear strength (τ) is calculated using the following formula.

In the formula, τ represents the interfacial shear strength, F represents the pulling load, d represents the fiber diameter of the single fiber, and L represents the droplet length.
The larger the value of the calculated interfacial shear strength (τ), the higher the adhesion between the carbon fiber and the polyamide, and by selecting a combination of the carbon fiber and the polyamide having a large value, the higher the low temperature It is also an indicator that a resin molded body having impact resistance is formed.

-Compatibilizer-
The compatibilizing agent is a resin that enhances the affinity between the thermoplastic resin and the polyamide.
What is necessary is just to determine according to a thermoplastic resin as a compatibilizing agent. However, as a compatibilizing agent, a compatibilizing agent having an acid value of 10 mgKOH / g or more and 60 mgKOH / g or less is applied.
The acid value of the compatibilizer is preferably from 10 mgKOH / g to 60 mgKOH / g, more preferably from 20 mgKOH / g to 55 mgKOH / g, from the viewpoint of further improving impact resistance at low temperatures.
The acid value of the compatibilizing agent is adjusted by, for example, the amount of modification site introduced when using a modified polyolefin described below as a compatibilizing agent.
The acid value of the compatibilizer is measured by a neutralization titration method according to JIS K-0070 (1992).
In addition, when using 2 or more types of compatibilizing agents from which an acid value differs as a compatibilizing agent, it is set as the acid value of the mixture of compatibilizing agents.

  As the compatibilizing agent, those having the same structure as the thermoplastic resin and including a part having affinity for polyamide in a part of the molecule are preferable.

For example, when polyolefin is used as the thermoplastic resin, a modified polyolefin may be used as the compatibilizing agent.
Here, if the thermoplastic resin is polypropylene (PP), the modified polyolefin (PP) is preferable as the modified polyolefin. Similarly, if the thermoplastic resin is an ethylene / vinyl acetate copolymer resin (EVA), the modified polyolefin is Modified ethylene / vinyl acetate copolymer resin (EVA) is preferred.

Examples of the modified polyolefin include polyolefins into which modified sites including a carboxy group, a carboxylic acid anhydride residue, a carboxylic acid ester residue, an imino group, an amino group, an epoxy group, and the like are introduced.
The modification site introduced into the polyolefin preferably contains a carboxylic acid anhydride residue from the viewpoint of further improving the affinity between the polyolefin and the polyamide and the maximum temperature during the molding process. It preferably contains an acid residue.

The modified polyolefin is a method in which a compound containing the above-mentioned modification site is reacted directly with the polyolefin and chemically bonded, or a method in which a graft chain is formed using the compound containing the above-mentioned modification site and this graft chain is bonded to the polyolefin, etc. There is.
Examples of the compound containing the above-mentioned modification site include maleic anhydride, fumaric anhydride, citric anhydride, N-phenylmaleimide, N-cyclohexylmaleimide, glycidyl (meth) acrylate, glycidyl vinyl benzoate, N- [4- (2, 3-epoxypropoxy) -3,5-dimethylbenzyl] acrylamide, alkyl (meth) acrylate, and derivatives thereof.
Among these, modified polyolefins obtained by reacting maleic anhydride, which is an unsaturated carboxylic acid, with polyolefins are preferred.

  Specific examples of the modified polyolefin include maleic anhydride modified polypropylene, maleic anhydride modified polyethylene, maleic anhydride modified ethylene / vinyl acetate copolymer resin (EVA), and adducts or copolymers thereof. .

A commercially available product may be used as the modified polyolefin.
Examples of the modified propylene include Yumex (registered trademark) series (1001, 1010) manufactured by Sanyo Chemical Industries.
Examples of the modified polyethylene include Yumex (registered trademark) series (2000) manufactured by Sanyo Chemical Industries, Ltd., and Modic (registered trademark) series manufactured by Mitsubishi Chemical Corporation.
Examples of the modified ethylene / vinyl acetate copolymer resin (EVA) include the Modic (registered trademark) series of Mitsubishi Chemical Corporation.

  The molecular weight of the compatibilizer is not particularly limited, but is preferably in the range of 50,000 to 100,000, and more preferably in the range of 50,000 to 80,000 from the viewpoint of workability.

The content of the compatibilizer is preferably 1 part by mass or more and 50 parts by mass or less, more preferably 2 parts by mass or more and 40 parts by mass or less, and more preferably 5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin. More preferably, it is at most parts.
The content of the compatibilizer is preferably 1 part by mass or more and 100 parts by mass or less, more preferably 5 parts by mass or more and 70 parts by mass or less, and more preferably 10 parts by mass or more and 50 parts by mass with respect to 100 parts by mass of the polyamide. More preferably, it is at most parts.
When the content of the compatibilizer is within the above range, the affinity between the thermoplastic resin and the polyamide is increased, and the impact resistance at low temperatures is improved.

The compatibilizer content is preferably proportional to the polyamide content (indirectly proportional to the carbon fiber content) from the viewpoint of increasing the affinity between the thermoplastic resin and the polyamide.
The content of the compatibilizer with respect to the mass of the carbon fiber is preferably 1% by mass to 100% by mass, more preferably 5% by mass to 70% by mass, and more preferably 10% by mass to 50% by mass. More preferably, it is as follows.
When the content of the compatibilizer with respect to the mass of the carbon fiber is 1% by mass or more, the affinity between the carbon fiber and the polyamide is easily obtained, and when the content is 100% by mass or less, the unreacted functional group that causes discoloration or deterioration Residual groups are suppressed.

-Other ingredients-
The resin composition according to the present embodiment may include other components in addition to the components described above.
Other components include, for example, flame retardants, flame retardant aids, anti-dripping agents when heated, plasticizers, antioxidants, mold release agents, light proofing agents, weathering agents, colorants, pigments, Modifier, antistatic agent, hydrolysis inhibitor, filler, reinforcing agent other than carbon fiber (talc, clay, mica, glass flake, milled glass, glass beads, crystalline silica, alumina, silicon nitride, aluminum nitride, Well-known additives such as boron nitride).
The other component is, for example, preferably 0 part by mass or more and 10 parts by mass or less, and more preferably 0 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin. Here, “0 part by mass” means a form that does not contain other components.

(Production method of resin composition)
The resin composition according to this embodiment is produced by melting and kneading the above components.
Here, a known means is used as the melt kneading means, and examples thereof include a twin screw extruder, a Henschel mixer, a Banbury mixer, a single screw extruder, a multi-screw extruder, and a kneader.
What is necessary is just to determine as temperature (cylinder temperature) in the case of melt-kneading according to the melting | fusing point etc. of the resin component which comprises a resin composition.

  In particular, the resin composition according to the present embodiment includes a thermoplastic resin, carbon fiber, and polyamide (a structural unit in which a polycarboxylic acid and a diamine are polycondensed, or a structural unit in which a lactam is ring-opened, and an aramid structural unit. It is preferably obtained by a production method including a step of melt-kneading a structural unit containing an aromatic ring excluding, a polyamide having a structural unit not containing an aromatic ring, and a compatibilizing agent. When a thermoplastic resin, carbon fiber, polyamide, and compatibilizer are melt-kneaded together, a polyamide coating layer is easily formed in a thin and nearly uniform state around the carbon fiber, and at low temperatures. Improves impact resistance.

[Resin molding]
The resin molded body according to this embodiment is a thermoplastic resin, carbon fiber, and polyamide (a structural unit obtained by polycondensation of dicarboxylic acid and diamine, or a structural unit obtained by ring opening of a lactam, excluding an aramid structural unit. A polyamide having a structural unit containing an aromatic ring and a structural unit not containing an aromatic ring), and a compatibilizing agent. That is, the resin molded body according to the present embodiment is configured with the same composition as the resin composition according to the present embodiment.

The resin molded body according to the present embodiment may be obtained by preparing the resin composition according to the present embodiment and molding the resin composition, or components other than carbon fibers. And a composition obtained by mixing the composition and carbon fiber at the time of molding.
As the molding method, for example, injection molding, extrusion molding, blow molding, hot press molding, calendar molding, coating molding, cast molding, dipping molding, vacuum molding, transfer molding, or the like may be applied.

The molding method of the resin molded body according to the present embodiment is preferably injection molding because it has a high degree of freedom in shape.
The cylinder temperature of injection molding is, for example, 180 ° C. or higher and 300 ° C. or lower, and preferably 200 ° C. or higher and 280 ° C. or lower. The mold temperature for injection molding is, for example, 30 ° C. or more and 100 ° C. or less, and more preferably 30 ° C. or more and 60 ° C. or less.
The injection molding may be performed using a commercially available apparatus such as NEX150 manufactured by Nissei Resin Industry, NEX300 manufactured by Nissei Resin Industry, SE50D manufactured by Sumitomo Machinery.

The resin molded body according to the present embodiment is suitably used for applications such as electronic / electrical equipment, office equipment, home appliances, automobile interior materials, and containers. More specifically, casings for electronic / electrical equipment and home appliances; various parts of electronic / electrical equipment and home appliances; interior parts for automobiles; storage cases such as CD-ROM and DVD; tableware; beverage bottles; Wrap material; film; sheet;
In particular, since the resin molded body according to the present embodiment uses a carbon fiber as a reinforcing fiber, the resin molded body has a higher mechanical strength, and thus is suitable for an alternative use for a metal part.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[Examples 1 to 18, Comparative Examples 1 to 7]
Ingredients according to Tables 1 to 3 (numerical values in the table indicate the number of parts) in a biaxial kneading apparatus (Toshiba Machine, TEM58SS), the following kneading conditions, and melt kneading shown in Tables 1 to 3 The mixture was kneaded at a temperature (cylinder temperature) to obtain pellets of a resin composition. In addition, the obtained pellet was baked at 600 degreeC for 2 hours, and the average fiber length of the carbon fiber which remained was measured by the above-mentioned method. The measurement results are shown in Tables 1 to 3.

-Kneading conditions-
・ Screw diameter: φ58mm
・ Rotation speed: 300rpm
・ Discharge nozzle diameter: 1mm

  The obtained pellets were subjected to an ISO multipurpose dumbbell test piece (ISO527 tensile) at an injection molding temperature (cylinder temperature) and a mold temperature of 50 ° C. shown in Tables 1 to 3 with an injection molding machine (NEX150, manufactured by Nissei Plastic Industries). Test, corresponding to ISO178 bending test) (test part thickness 4 mm, width 10 mm) and D2 test piece (length 60 mm, width 60 mm, thickness 2 mm) were molded.

[Evaluation]
The following evaluation was performed using the obtained two kinds of test pieces.
The evaluation results are shown in Tables 1 to 3.

-Charpy impact strength at low temperatures (impact resistance at low temperatures)-
The obtained ISO multipurpose dumbbell test piece was formed by providing gates on both sides in the length direction and then notched. And after leaving it for 24 hours in the low temperature test room of -30 degreeC using the test piece, based on JIS-K7111 (2006), with an evaluation apparatus (Toyo Seiki Co., Ltd. product DG-UB2). The Charpy impact strength (kJ / m ² ) was measured from the Charpy impact test.

-Flexural modulus-
About the obtained ISO multipurpose dumbbell test piece, the bending elastic modulus was measured by the method based on ISO178 using the universal testing apparatus (Shimadzu Corp. make, autograph AG-Xplus).

-Appearance quality-
The obtained D2 test piece was observed, and the appearance quality was evaluated as follows.
The surface of the test piece was visually observed, and the presence or absence of a dent in the flat part of the molded body and the surface properties were evaluated. The evaluation criteria are as follows.
A: The surface portion has no domain-like defects and the entire surface is uniform.
B: Although a domain-like unevenness of 1 mm is observed on the surface portion, the touch feels almost uniform.
C: There is a domain-like unevenness of 1 mm or more on the surface part, and when the domain part is touched with a finger, a tactile sensation different from other places is felt.
D: A dent occurs in the flat portion of the molded body.

-Presence or absence of coating layer-
Using the obtained D2 test piece, the presence or absence of a coating layer made of polyamide was confirmed according to the method described above.

The details of the material types in Tables 1 to 3 are as follows.
-Thermoplastic resin-
・ Polypropylene (Novatech (registered trademark) PP MA3, manufactured by Nippon Polypro Co., Ltd.)
-Reinforcing fiber-
Carbon fiber (with surface treatment, chopped carbon fiber trading card (registered trademark), manufactured by Toray Industries, Inc., average fiber length 20 mm, average diameter 7 μm)
-Aliphatic PA (aliphatic polyamide)-
PA6 (nylon 6, Zytel (registered trademark) 7331J, manufactured by Dupont)
PA66 (nylon 66, 101L, manufactured by Dupont)
-Aromatic PA (aromatic polyamide)-
・ MXD6 (MXD6, manufactured by Mitsubishi Gas Chemical Company)
・ PA9T (Nylon 9T, GENESTAR PA9T, Kuraray)
-Compatibilizer-
-Maleic anhydride modified polypropylene (Yumex (registered trademark) 1001, manufactured by Sanyo Chemical Industries, Ltd., acid value = 26 mgKOH / g
-Maleic anhydride modified polypropylene (Yumex (registered trademark) 1010, manufactured by Sanyo Chemical Industries, Ltd., acid value = 52 mgKOH / g
-Maleic anhydride modified polypropylene (Yumex (registered trademark) 110TS, manufactured by Sanyo Chemical Industries, Ltd., acid value = 7 mgKOH / g

From the above results, it can be seen that in this example, a resin molded product having excellent Charpy impact strength at low temperature (impact resistance at low temperature) can be obtained as compared with the comparative example.
In addition, in this example, it can also be seen that a resin molded article excellent in bending elastic modulus, tensile elastic modulus, and appearance quality can be obtained.

  In addition, when the molded object produced in each Example was analyzed by the above-mentioned method, the layer of the used compatibilizer (maleic anhydride modified polypropylene layer) was interposed between the coating layer and the thermoplastic resin. It was confirmed that a compatibilizer layer was formed on the surface of the coating layer.

Claims (28)

A thermoplastic resin;
Carbon fiber,
Polyamide,
A compatibilizer having an acid value of 10 mgKOH / g or more and 60 mgKOH / g or less;
A resin composition comprising:   The polyamide is a structural unit in which a dicarboxylic acid and a diamine are polycondensated, or a structural unit in which a lactam is opened, and includes a structural unit that includes an aromatic ring excluding an aramid structural unit, and a structural unit that does not include an aromatic ring. The resin composition according to claim 1, which is a polyamide having. The structural unit containing the aromatic ring is at least one of the following structural units (1) and (2);
The resin composition according to claim 2, wherein the structural unit not containing the aromatic ring is at least one of the following structural units (3) and (4).
Structural unit (1): — (— NH—Ar ¹ —NH—CO—R ¹ —CO —) —
(In the structural unit (1), Ar ¹ represents a divalent organic group containing an aromatic ring. R ¹ represents a divalent organic group containing no aromatic ring.)
Structural unit (2): — (— NH—R ² —NH—CO—Ar ² —CO —) —
(In the structural unit (2), Ar ² represents a divalent organic group containing an aromatic ring. R ² represents a divalent organic group containing no aromatic ring.)
Structural unit (3): — (— NH—R ³¹ —NH—CO—R ³² —CO —) —
(In the structural unit (3), R ³¹ represents a divalent organic group containing no aromatic ring. R ³² represents a divalent organic group containing no aromatic ring.)
Structural unit (4): — (— NH—R ⁴ —CO —) —
(In the structural unit (4), R ⁴ represents a divalent organic group containing no aromatic ring)   The polyamide according to claim 2 or 3, wherein the polyamide is a copolymerized polyamide obtained by copolymerizing a first polyamide having a structural unit containing the aromatic ring and a second polyamide having a structural unit not containing the aromatic ring. The resin composition as described.   The resin according to claim 2 or 3, wherein the polyamide is a mixed polyamide containing a first polyamide having a structural unit containing the aromatic ring and a second polyamide having a structural unit not containing the aromatic ring. Composition.   The resin composition according to any one of claims 2 to 5, wherein a ratio of the aromatic ring of the polyamide is 10% by mass or more and 40% by mass or less.   The resin composition according to any one of claims 1 to 6, wherein an average fiber length of the carbon fibers is from 0.1 mm to 5.0 mm.   The resin composition according to any one of claims 1 to 7, wherein the thermoplastic resin is a polyolefin.   The resin composition according to any one of claims 1 to 8, wherein the compatibilizer is a modified polyolefin.   The resin composition according to any one of claims 1 to 9, wherein a content of the carbon fiber is 0.1 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.   The resin composition according to any one of claims 1 to 10, wherein a content of the polyamide is 0.1 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.   The resin composition according to any one of claims 1 to 11, wherein a content of the compatibilizing agent is 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.   The resin composition according to any one of claims 1 to 12, wherein a content of the polyamide with respect to a mass of the carbon fiber is 1% by mass or more and 200% by mass or less.   The resin composition according to any one of claims 1 to 13, wherein a content of the compatibilizing agent with respect to a mass of the carbon fiber is 1% by mass or more and 100% by mass or less. A thermoplastic resin;
Carbon fiber,
Polyamide,
A compatibilizer having an acid value of 10 mgKOH / g or more and 60 mgKOH / g or less;
A resin molded body containing   The polyamide is a structural unit in which a dicarboxylic acid and a diamine are polycondensated, or a structural unit in which a lactam is opened, and includes a structural unit that includes an aromatic ring excluding an aramid structural unit, and a structural unit that does not include an aromatic ring. The resin molded body according to claim 15, which is a polyamide having. The structural unit containing the aromatic ring is at least one of the following structural units (1) and (2);
The resin molded body according to claim 16, wherein the structural unit not containing an aromatic ring is at least one of the following structural units (3) and (4).
Structural unit (1): — (— NH—Ar ¹ —NH—CO—R ¹ —CO —) —
(In the structural unit (1), Ar ¹ represents a divalent organic group containing an aromatic ring. R ¹ represents a divalent organic group containing no aromatic ring.)
Structural unit (2): — (— NH—R ² —NH—CO—Ar ² —CO —) —
(In the structural unit (2), Ar ² represents a divalent organic group containing an aromatic ring. R ² represents a divalent organic group containing no aromatic ring.)
Structural unit (3): — (— NH—R ³¹ —NH—CO—R ³² —CO —) —
(In the structural unit (3), R ³¹ represents a divalent organic group containing no aromatic ring. R ³² represents a divalent organic group containing no aromatic ring.)
Structural unit (4): — (— NH—R ⁴ —CO —) —
(In the structural unit (4), R ⁴ represents a divalent organic group containing no aromatic ring)   The polyamide according to claim 16 or 17, wherein the polyamide is a copolymerized polyamide obtained by copolymerizing a first polyamide having a structural unit containing the aromatic ring and a second polyamide having a structural unit not containing the aromatic ring. The resin molding as described.   The resin molded body according to claim 16 or 17, wherein the polyamide is a mixed polyamide containing a first polyamide having an aromatic ring and a second polyamide having no aromatic ring.   The resin molded body according to any one of claims 16 to 19, wherein a ratio of an aromatic ring of the polyamide is 10 mass% or more and 40 mass% or less. The resin molded body according to any one of claims 15 to 20, wherein an average fiber length of the carbon fibers is 0.1 mm or more and 5.0 mm or less.   The resin molded body according to any one of claims 15 to 21, wherein the thermoplastic resin is a polyolefin.   The resin molded article according to any one of claims 15 to 22, wherein the compatibilizing agent is a modified polyolefin.   The resin molded body according to any one of claims 15 to 23, wherein a content of the carbon fiber is 0.1 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.   The resin molded body according to any one of claims 15 to 24, wherein a content of the polyamide is 0.1 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.   The resin molded body according to any one of claims 15 to 25, wherein a content of the compatibilizing agent is 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.   27. The resin molded body according to any one of claims 15 to 26, wherein a content of the polyamide with respect to a mass of the carbon fiber is 1% by mass or more and 200% by mass or less.   The resin molded body according to any one of claims 15 to 27, wherein a content of the compatibilizing agent with respect to a mass of the carbon fiber is 1% by mass or more and 100% by mass or less.