JP7587458B2 - Fiber-reinforced resin composition, laminate and molded body - Google Patents

Description

The present invention relates to a fiber-reinforced resin composition, a laminate, and a molded body.

A thin-film fiber-reinforced resin (hereinafter simply referred to as "Uni-Direction (UD) sheet") is known, which contains multiple reinforcing fibers oriented in one direction and a resin composition (matrix resin) impregnated into the reinforcing fibers. This UD sheet is lighter than metal and has high mechanical strength, so its use as a reinforcing material for covering the surface of a resin molded body is being considered. In addition, a pellet-shaped resin composition (Long Fiber Thermoplastics: LFT) containing multiple reinforcing fibers oriented in one direction and a resin composition (matrix resin) impregnated into the reinforcing fibers is also being considered for use in various applications.

Patent Document 1 describes a thermoplastic composite material in which a semi-crystalline polyamide having a component unit derived from terephthalic acid or isophthalic acid as a diamine component is dispersed between carbon fibers aligned parallel to each other or woven together. According to Patent Document 1, the above-mentioned thermoplastic composite material is said to be less susceptible to cracking.

Special Publication No. 2020-512453

Patent Document 1 describes a composite material in which carbon fibers are impregnated with a semi-crystalline polyamide resin. However, according to the findings of the present inventors, a laminate in which multiple layers of the composite material described in Patent Document 1 are laminated and fused together has a problem in that it has poor interlaminar shear strength.

In view of the above problems, the present invention aims to provide a fiber-reinforced resin composition that is made by impregnating reinforcing fibers with a polyamide resin and that can also increase the interlaminar shear strength of a laminate that is laminated and fused in multiple layers, a laminate obtained by laminating the composition, and a molded article obtained by molding the composition.

A fiber-reinforced resin composition according to one aspect of the present invention for solving the above problems includes a plurality of arranged reinforcing fibers, and at least one additive selected from the group consisting of a crystalline semi-aromatic polyamide resin (A), an amorphous semi-aromatic polyamide resin (B), an organic lubricant, and a viscosity modifier containing a compound having a carboxy group in the molecule.

The laminate according to one aspect of the present invention, which aims to solve the above problems, is formed by laminating the fiber-reinforced resin composition and welding them together.

The molded article according to one aspect of the present invention, which is intended to solve the above problems, is produced by molding the fiber-reinforced resin composition.

The present invention provides a fiber-reinforced resin composition that is made by impregnating reinforcing fibers with a polyamide resin and that can increase the interlaminar shear strength of a laminate that is laminated and fused in multiple layers, a laminate obtained by laminating the composition, and a molded article obtained by molding the composition.

For the numerical ranges described in this specification in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Also, in the numerical ranges described in this specification, the upper or lower limit value described in one numerical range may be replaced with a value shown in the examples.

In this specification, when the amount of each component in a composition contains multiple substances corresponding to each component, the amount refers to the total amount of the multiple substances present in the composition, unless otherwise specified.

The present inventors have conducted various studies to determine why the composite material described in Patent Document 1 has poor interlaminar shear strength, and have found that the polyamide resin does not sufficiently impregnate the carbon fibers in the composite material. Therefore, even if the composite material is laminated and fused, the polyamide resin between the layers does not fuse sufficiently, which is thought to result in low interlaminar shear strength. Based on the above findings, the present inventors have conducted extensive research into a method for increasing the fluidity of the polyamide resin to sufficiently impregnate the fiber-reinforced resin composition with the polyamide resin, thereby increasing the interlaminar shear strength of a laminate formed by laminating and fusing the fiber-reinforced resin compositions, and have arrived at the present invention.

One embodiment of the present invention relates to a fiber-reinforced resin composition (hereinafter, also simply referred to as a "resin composition") that includes a plurality of arranged reinforcing fibers, a crystalline semi-aromatic polyamide resin, and at least one additive selected from the group consisting of an amorphous semi-aromatic polyamide resin, an organic lubricant, and a viscosity modifier containing a compound having a carboxy group in the molecule. Typically, the resin composition includes the reinforcing fibers, a crystalline semi-aromatic polyamide resin as a matrix resin impregnated into the reinforcing fibers, and the additive.

[Reinforced fiber]
The material of the reinforcing fiber is not particularly limited. For example, carbon fiber, glass fiber, aramid fiber, alumina fiber, silicon carbide fiber, boron fiber, metal fiber, etc. can be used as the reinforcing fiber. Among these, carbon fiber is preferred because it has excellent mechanical properties and can reduce the weight of the molded product. Examples of the carbon fiber include PAN-based carbon fiber, pitch-based carbon fiber, and rayon-based carbon fiber. Among these, PAN-based carbon long fiber is preferred because it has an excellent balance between strength and elastic modulus.

The carbon fiber preferably has a surface oxygen concentration ratio [O/C], which is the ratio of the number of oxygen (O) and carbon (C) atoms on the surface of the carbon fiber measured by X-ray photoelectron spectroscopy, of 0.05 or more and 0.5 or less, more preferably 0.08 or more and 0.4 or less, and even more preferably 0.1 or more and 0.3 or less. When the surface oxygen concentration ratio is 0.05 or more, a sufficient amount of functional groups can be secured on the carbon fiber surface, and the adhesion to the matrix resin can be further improved. When the surface oxygen concentration ratio is 0.5 or less, the carbon fiber has excellent handleability and productivity. The surface oxygen concentration ratio [O/C] can be measured by the method described in International Publication No. 2017/183672. The surface oxygen concentration ratio [O/C] can be controlled by known methods including electrolytic oxidation treatment, chemical oxidation treatment, and gas phase oxidation treatment, but control by electrolytic oxidation treatment is preferred.

From the viewpoint of fully enhancing the strength-improving effect of the reinforcing fibers, the average diameter of the reinforcing fibers is preferably 1 μm or more and 20 μm or less, more preferably 3 μm or more and 15 μm or less, and even more preferably 4 μm or more and 10 μm or less.

The length of the reinforcing fibers is usually 15 mm or more. The lower limit of the length of the reinforcing fibers is preferably 20 mm or more, more preferably 100 mm or more, and even more preferably 500 mm or more. The maximum upper limit of the length of the reinforcing fibers is preferably the same as the maximum length of the UD sheet, for example 50 m. Usually, the UD sheet used in the resin molded product described below is a UD sheet that is cut to the desired length after production. Therefore, the length of the reinforcing fibers contained in the UD sheet contained in the resin molded product may be smaller than the minimum length mentioned above.

The reinforcing fibers are preferably those formed by opening fiber bundles that have been bundled with a bundling agent (sizing agent). The number of single threads in the fiber bundle is not particularly limited, but is usually 100 to 350,000, preferably 1,000 to 250,000, and more preferably 5,000 to 220,000.

The sizing agent may be any known sizing agent, including olefin-based emulsions, urethane-based emulsions, epoxy-based emulsions, nylon-based emulsions, etc.

The reinforcing fibers may be arranged in a plurality of directions, and the fiber-reinforced resin composition may contain only reinforcing fibers arranged in one direction, or may contain reinforcing fibers arranged in multiple directions that are different from each other. When reinforcing fibers arranged in multiple directions are included, these reinforcing fibers may be woven.

[Crystalline semi-aromatic polyamide resin (A)]
The crystalline semi-aromatic polyamide resin (A) (hereinafter, simply referred to as "polyamide resin (A)") is a semi-aromatic polyamide resin having crystallinity. The polyamide resin (A) can increase the mechanical strength, such as the tensile strength and Young's modulus, of a fiber-reinforced resin composition and a laminate and a molded product of the fiber-reinforced resin composition.

In this specification, a polyamide resin having crystallinity means that the heat of fusion (ΔH) measured by the measurement method described below is 20.0 J/g or more.

In this specification, semi-aromatic polyamide resin means a polyamide resin containing a structural unit having an aromatic ring and a structural unit having an aliphatic chain. The polyamide resin (A) preferably has a structure containing a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine. In this case, in order to increase the crystallinity of the polyamide resin, the component unit (Aa) derived from a dicarboxylic acid preferably contains a component unit derived from an aromatic dicarboxylic acid or an alicyclic dicarboxylic acid.

(Component unit (Aa) derived from dicarboxylic acid)
More specifically, in this embodiment, the component unit (Aa) derived from a dicarboxylic acid preferably includes a component unit (Aa1) derived from at least one selected from the group consisting of terephthalic acid and naphthalenedicarboxylic acid. These component units (Aa1) can increase the crystallinity of polyamide, unlike, for example, component units derived from isophthalic acid. Among them, from the viewpoint of obtaining a polyamide resin with high crystallinity and high heat resistance, it is preferable that the component unit (Aa) derived from a dicarboxylic acid includes a component unit derived from terephthalic acid. When the component unit (Aa) includes a component unit derived from terephthalic acid, the interlaminar shear strength tends to be further improved, which is preferable.

From the viewpoint of ensuring the crystallinity of the polyamide resin, the content of these component units (Aa1) is preferably more than 20 mol% and not more than 100 mol% based on the total number of moles of the component units (Aa) derived from dicarboxylic acid. From the viewpoint of further increasing the crystallinity of the polyamide resin and further improving the interlaminar shear strength of the laminate of the fiber-reinforced resin composition, the content of these component units (Aa1) is preferably 45 mol% to 100 mol%, more preferably 50 mol% to 100 mol%, even more preferably 60 mol% to 100 mol%, and particularly preferably 80 mol% to 100 mol% based on the total number of moles of the component units (Aa) derived from dicarboxylic acid. In addition, from the viewpoint of further improving the impregnation property of the resin composition, the content of these component units (Aa1) is preferably 25 mol% to 99 mol%, more preferably 40 mol% to 80 mol%. A plurality of types of these component units may be contained in the polyamide resin (A).

The component unit (Aa) derived from a dicarboxylic acid may contain an aromatic carboxylic acid component unit (Aa2) other than the component unit (Aa1) or a component unit (Aa3) derived from an aliphatic dicarboxylic acid, as long as the effects of the present invention are not impaired.

Examples of the component unit (Aa2) derived from an aromatic dicarboxylic acid other than the component unit (Aa1) include component units derived from isophthalic acid, 2-methylterephthalic acid, orthophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, furandicarboxylic acid, and 5-sodiumsulfoisophthalic acid. Among these, it is preferable that the component unit (Aa2) contains a component unit derived from isophthalic acid. A plurality of types of these component units may be contained in the polyamide resin (A). The component unit (Aa2) can adjust the impregnation property of the resin composition.

When the polyamide resin (A) contains the component unit (Aa2), the content of these component units (Aa2) is preferably 1 mol% or more and 50 mol% or less, more preferably 10 mol% or more and 40 mol% or less, even more preferably 15 mol% or more and 40 mol% or less, and particularly preferably 20 mol% or more and 40 mol% or less, based on the total number of moles of the component units (Aa) derived from dicarboxylic acid, from the viewpoint of ensuring the crystallinity of the polyamide resin and from the viewpoint of further improving the impregnation property of the resin composition. When the polyamide resin (A) contains the component unit (Aa2), the content of these component units (Aa2) is preferably more than 0 mol% and 50 mol% or less, more preferably more than 0 mol% and 20 mol% or less, and even more preferably more than 0 mol% and 10 mol%, based on the total number of moles of the component units (Aa) derived from dicarboxylic acid, from the viewpoint of ensuring the crystallinity of the polyamide resin and from the viewpoint of increasing the interlaminar shear strength of the laminate of the fiber reinforced resin composition.

The component unit (Aa3) derived from an aliphatic dicarboxylic acid is preferably a component unit derived from an aliphatic dicarboxylic acid having 3 to 20 carbon atoms. Examples of the component unit (Aa3) derived from a dialiphatic dicarboxylic acid include component units derived from linear or branched aliphatic dicarboxylic acids such as malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, 3,3-diethylsuccinic acid, azelaic acid, sebacic acid, suberic acid, decanedicarboxylic acid, undecanedicarboxylic acid, and dodecanedicarboxylic acid. The component unit (Aa3) derived from an aliphatic dicarboxylic acid also includes component units derived from alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and cyclopentanedicarboxylic acid. Among these, the component unit (Aa3) preferably includes component units derived from adipic acid and sebacic acid. These component units may be contained in multiple types in the polyamide resin (A). The component unit (Aa3) tends to adjust the melting point and crystallinity of the resin composition, thereby further improving moldability.

When the polyamide resin (A) contains the component unit (Aa3), the content of the component unit (Aa3) is preferably more than 0 mol% and not more than 40 mol%, more preferably more than 0 mol% and not more than 20 mol%, even more preferably 1 mol% or more and not more than 10 mol%, and particularly preferably 1 mol% or more and not more than 5 mol%, based on the total number of moles of the component unit (Aa) derived from the dicarboxylic acid, from the viewpoint of ensuring the crystallinity of the polyamide resin.

In addition to the above-mentioned component units (Aa1), (Aa2), and (Aa3), the polyamide resin (A) may further contain a small amount of trivalent or higher polycarboxylic acid component units such as trimellitic acid and pyromellitic acid monoanhydrides. From the viewpoint of suppressing gelation of the polyamide resin (A), the content of such polycarboxylic acid component units can be 0 mol % or more and 5 mol % or less based on the total number of moles of the component units (Aa) derived from dicarboxylic acids.

(Component unit (Ab) derived from diamine)
The component unit (Ab) derived from a diamine preferably includes a component unit (Ab1) derived from a linear alkylenediamine having from 4 to 18 carbon atoms, and may further include a component unit (Ab2) derived from an alkylenediamine having from 4 to 18 carbon atoms and having a side chain alkyl group, or a component unit (Ab3) derived from an alicyclic diamine having from 4 to 20 carbon atoms.

In this specification, the number of carbon atoms in a component unit derived from an alkylenediamine having a side chain alkyl group is the sum of the number of carbon atoms in the main chain alkylene group and the number of carbon atoms in the side chain alkyl group, unless otherwise specified.

Examples of the component unit (Ab1) derived from a linear alkylenediamine having 4 to 18 carbon atoms include component units derived from 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, and 1,12-diaminododecane. Among these, component units derived from 1,6-diaminohexane, 1,8-diaminooctane, 1,10-diaminodecane, and 1,12-diaminododecane are preferred, with 1,6-diaminohexane component units being more preferred. A plurality of types of these component units may be contained in the polyamide resin (A).

When the total number of moles of the diamine-derived component units contained in the polyamide resin (A) is taken as 100 mol%, the amount of the component unit (Ab1) derived from a linear alkylene diamine having 4 to 18 carbon atoms is preferably 20 mol% or more and 100 mol% or less, and more preferably 20 mol% or more and 80 mol% or less. When the content of the above component unit is 20 mol% or more, the crystallization rate is not too slow, so that it is easy to moderately increase the crystallinity and mechanical strength of the polyamide resin (A). When the content of the above component unit is 100 mol% or less, preferably 80 mol% or less, the crystallization rate of the polyamide resin (A) is not too high, so that it is easy to increase the fluidity of the matrix resin and increase the interlaminar shear strength. From the same viewpoint, it is more preferable that the content of the component unit derived from a linear aliphatic diamine is 30 mol% or more and 60 mol% or less of the above total.

Examples of component units (Ab2) derived from alkylenediamines having 4 to 18 carbon atoms and having a side chain alkyl group include 1-butyl-1,2-diamino-ethane, 1,1-dimethyl-1,4-diamino-butane, 1-ethyl-1,4-diamino-butane, 1,2-dimethyl-1,4-diamino-butane, 1,3-dimethyl-1,4-diamino-butane, 1,4-dimethyl-1,4-diamino-butane, 2,3-dimethyl-1,4-diamino-butane, 2-methyl-1,5-diaminopentane, 2-methyl-1,6-diaminohexane, 2-methyl-1, 7-diaminoheptane, 2-methyl-1,8-diaminooctane, 2-methyl-1,9-diaminononane, 2-methyl-1,10-diaminodecane, 2-methyl-1,11-diaminoundecane, 2,5-dimethyl-1,6-diaminohexane, 2,4-dimethyl-1,6-diaminohexane, 3,3-dimethyl-1,6-diaminohexane, 2,2-dimethyl-1,6-diaminohexane, 2,2,4-trimethyl-1,6-diaminohexane, 2,4,4-trimethyl-1,6-diaminohexane, 2,4-diethyl-1,6-diamino hexane, 2,3-dimethyl-1,7-diamino-heptane, 2,4-dimethyl-1,7-diamino-heptane, 2,5-dimethyl-1,7-diamino-heptane, 2,2-dimethyl-1,7-diamino-heptane, 2-methyl-4-ethyl-1,7-diamino-heptane, 2-ethyl-4-methyl-1,7-diamino-heptane, 2,2,5,5-tetramethyl-1,7-diamino-heptane, 3-isopropyl-1,7-diamino-heptane, 3-isooctyl-1,7-diamino-heptane, 1,3-dimethyl-1,8-diamino-octane , 1,4-dimethyl-1,8-diamino-octane, 2,4-dimethyl-1,8-diamino-octane, 3,4-dimethyl-1,8-diamino-octane, 4,5-dimethyl-1,8-diamino-octane, 2,2-dimethyl-1,8-diamino-octane, 3,3-dimethyl-1,8-diamino-octane, 4,4-dimethyl-1,8-diamino-octane, 3,3,5-trimethyl-1,8-diamino-octane, 2,4-diethyl-1,8-diamino-octane, and 5-methyl-1,9-diamino-nonane. Of these, from the viewpoint of further improving the interlaminar shear strength of the laminate of the fiber-reinforced resin composition, component units derived from side-chain alkyldiamines having 1 to 2 side-chain alkyl groups with 1 to 2 carbon atoms and 4 to 10 carbon atoms in the main chain are preferred, and component units derived from 2-methyl-1,5-diaminopentane and 2-methyl-1,8-diaminooctane are more preferred. A plurality of types of these component units may be contained in the polyamide resin (A).

Examples of component units (Ab3) derived from alicyclic diamines having 4 to 20 carbon atoms include 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, isophoronediamine, piperazine, 2,5-dimethylpiperazine, bis(4-aminocyclohexyl)methane, bis(4-aminocyclohexyl)propane, 4,4'-diamino-3,3'-dimethyldicyclohexylpropane, 4,4'-diamino-3,3'-dimethyldicyclohexyl These include component units derived from 4,4'-diamino-3,3'-dimethyl-5,5'-dimethyldicyclohexylmethane, 4,4'-diamino-3,3'-dimethyl-5,5'-dimethyldicyclohexylpropane, α,α'-bis(4-aminocyclohexyl)-p-diisopropylbenzene, α,α'-bis(4-aminocyclohexyl)-m-diisopropylbenzene, α,α'-bis(4-aminocyclohexyl)-1,4-cyclohexane, and α,α'-bis(4-aminocyclohexyl)-1,3-cyclohexane. Among these, component units derived from 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(aminomethyl)cyclohexane, bis(4-aminocyclohexyl)methane, and 4,4'-diamino-3,3'-dimethyldicyclohexylmethane are preferred, and component units derived from 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 1,3-bis(aminocyclohexyl)methane, and 1,3-bis(aminomethyl)cyclohexane are more preferred. A plurality of types of these component units may be contained in the polyamide resin (A).

When the polyamide resin (A) contains a component unit (Ab2) derived from an alkylene diamine having 4 to 18 carbon atoms and a side chain alkyl group or a component unit (Ab3) derived from an alicyclic diamine having 4 to 20 carbon atoms, the total content of these component units is preferably 20 mol% to 80 mol% when the total number of moles of the component units derived from the diamine contained in the polyamide resin (A) is taken as 100 mol%. When the total content of the above component units is 20 mol% or more, the crystallization rate of the polyamide resin (A) tends to be moderately slow, so that the fluidity of the matrix resin is easily increased and the interlaminar shear strength is easily increased. When the content of the above component units is 80 mol% or less, the crystallinity and mechanical strength of the polyamide resin (A) are not easily impaired. From the same viewpoint, it is more preferable that the total content of these component units is 40 mol% to 70 mol% of the above total.

When the polyamide resin (A) contains a component unit derived from a trifunctional or higher polyfunctional amine compound, the amount of the component unit added is preferably an amount that does not cause the resin to gel, specifically, 10 mol % or less out of a total of 100 mol % of all component units derived from amines.

In addition to the above-mentioned component units (Ab1) derived from linear alkylenediamines having 4 to 18 carbon atoms, component units (Ab2) derived from alkylenediamines having 4 to 18 carbon atoms and having a side chain alkyl group, and component units (Ab3) derived from alicyclic diamines having 4 to 20 carbon atoms, polyamide resin (A) may also contain a small amount of component units derived from other diamines, such as component units derived from metaxylylenediamine. The content of such component units derived from other diamines may be 50 mol % or less, and preferably 40 mol % or less, based on the total amount of component units (Ab) derived from diamines.

(End-capping agent)
In order to improve the thermal stability during compounding or molding and to further increase the mechanical strength, at least a part of the molecular end groups of the polyamide resin (A) may be capped with a terminal capping agent. When the molecular end is a carboxyl group, the terminal capping agent is preferably a monoamine, and when the molecular end is an amino group, the terminal capping agent is preferably a monocarboxylic acid.

Examples of monoamines include aliphatic monoamines such as methylamine, ethylamine, propylamine, and butylamine, alicyclic monoamines such as cyclohexylamine and dicyclohexylamine, and aromatic monoamines such as aniline and toluidine. Examples of monocarboxylic acids include aliphatic monocarboxylic acids having 2 to 30 carbon atoms such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid, aromatic monocarboxylic acids such as benzoic acid, toluic acid, naphthalene carboxylic acid, methylnaphthalene carboxylic acid, and phenyl acetic acid, and alicyclic monocarboxylic acids such as cyclohexane carboxylic acid. Aromatic monocarboxylic acids and alicyclic monocarboxylic acids may have a substituent on the ring structure portion.

(Physical properties, etc.)
The polyamide resin (A) can have a melting point (Tm) of 270°C or more and 340°C or less. When the melting point (Tm) of the polyamide resin (A) is 270°C or more, the mechanical strength and heat resistance of the resin composition and the molded body in the high temperature range are not easily impaired, and when it is 340°C or less, the molding temperature does not need to be excessively high, so that the molding processability of the resin composition is likely to be good. From the above viewpoint, the melting point (Tm) of the polyamide resin is more preferably 290°C or more and 340°C or less, and even more preferably 315°C or more and 340°C or less.

The polyamide resin (A) may have a glass transition temperature (Tg) of 80°C or higher and 150°C or lower.

The heat of fusion (ΔH) of the polyamide resin (A) is preferably 20.0 J/g or more. When the heat of fusion (ΔH) of the polyamide resin (A) is 20.0 J/g or more, the resin member has crystallinity, and therefore the heat resistance of the resin member is easily improved. From the above viewpoint, the heat of fusion (ΔH) of the polyamide resin (A) is preferably 25.0 J/g or more, and more preferably 30.0 J/g or more. The upper limit of the heat of fusion (ΔH) of the polyamide resin (A) is not particularly limited, but from the viewpoint of not impairing the moldability, it can be 130 J/g, and is preferably 100 J/g or less.

The heat of fusion (ΔH), melting point (Tm) and glass transition temperature (Tg) of polyamide resin can be measured using a differential scanning calorimeter (DSC220C, manufactured by Seiko Instruments Inc.).

Specifically, about 5 mg of crystalline polyamide resin is sealed in a measuring aluminum pan and heated from room temperature to 350°C at 10°C/min. In order to completely melt the resin, it is held at 350°C for 3 minutes and then cooled to 30°C at 10°C/min. After leaving it at 30°C for 5 minutes, it is heated a second time to 350°C at 10°C/min. The temperature (°C) of the endothermic peak in this second heating is the melting point (Tm) of the crystalline polyamide resin, and the transition point corresponding to the glass transition is the glass transition temperature (Tg). The heat of fusion (ΔH) is determined from the area of the endothermic peak during melting in the first heating process in accordance with JIS K7122.

The melting point (Tm), glass transition temperature (Tg) and heat of fusion (ΔH) of polyamide resin (A) can be adjusted, for example, by the composition of the component unit (Aa1) derived from the above-mentioned dicarboxylic acid or the number of carbon atoms per component unit (Ab1) derived from the diamine. In order to increase the melting point of polyamide resin (A), for example, the content ratio of the component unit derived from terephthalic acid may be increased.

The intrinsic viscosity [η] of the polyamide resin (A) measured at a temperature of 25°C in 96.5% sulfuric acid is preferably 0.5 dl/g or more and 1.25 dl/g or less. When the intrinsic viscosity [η] of the polyamide resin (A) is 0.5 dl/g or more, the mechanical strength (toughness, etc.) of the molded body is easily increased, and when it is 1.25 dl/g or less, the fluidity of the resin composition during molding is not easily impaired. From the same viewpoint, the intrinsic viscosity [η] of the polyamide resin (A) is more preferably 0.6 dl/g or more and 1.15 dl/g or less, and even more preferably 0.6 dl/g or more and 1.05 dl/g or less. The intrinsic viscosity [η] can be adjusted by the amount of terminal blocking of the polyamide resin (A), etc.

The intrinsic viscosity of polyamide resin (A) can be measured in accordance with JIS K6810 (1977). Specifically, 0.5 g of polyamide resin (A) is dissolved in 50 ml of 96.5% sulfuric acid solution to prepare a sample solution. The flow time of this sample solution is measured under conditions of 25±0.05° C. using an Ubbelohde viscometer, and the obtained value can be applied to the following formula to calculate the intrinsic viscosity.
[η]=ηSP/[C(1+0.205ηSP)]

In the above formula, each algebra or variable represents the following:
[η]: Intrinsic viscosity (dl/g)
ηSP: specific viscosity C: sample concentration (g/dl)

ηSP is calculated by the following formula:
ηSP=(t-t0)/t0
t: number of seconds for sample solution to flow (seconds)
t0: Number of seconds (seconds) for blank sulfuric acid to flow

(Production method)
The polyamide resin (A) can be produced, for example, by polycondensing the above-mentioned dicarboxylic acid and the above-mentioned diamine in a homogeneous solution. Specifically, the dicarboxylic acid and the diamine are heated in the presence of a catalyst as described in WO 03/085029 to obtain a low-order condensate, and then the melt of the low-order condensate is subjected to shear stress to polycondense the low-order condensate.

The aforementioned end-capping agent may be added to the reaction system in order to adjust the intrinsic viscosity of the polyamide resin. The intrinsic viscosity [η] (or molecular weight) of the polyamide resin can be adjusted by the amount of end-capping agent added.

The end-capping agent is added to the reaction system of the dicarboxylic acid and the diamine. The amount added is preferably 0.07 moles or less, and more preferably 0.05 moles or less, per mole of the total amount of dicarboxylic acid.

The content of polyamide resin (A) is preferably 60 parts by mass or more and 99.99 parts by mass or less, more preferably 70 parts by mass or more and 99.9 parts by mass or less, and even more preferably 75 parts by mass or more and 99.0 parts by mass or less, when the total mass of the resin components contained in the resin composition is 100 parts by mass. When the content of polyamide resin (A) is equal to or more than the lower limit, the tensile strength and Young's modulus of the fiber reinforced resin composition and the laminate and molded product of the fiber reinforced resin composition tend to be further improved. When the content of polyamide resin (A) is equal to or less than the upper limit, the interlaminar shear strength tends to be further improved.

[Additives]
The additive increases the fluidity of the polyamide resin (A) and allows the polyamide resin (A) to be more fully impregnated into the resin composition, which is believed to increase the amount of polyamide resin (A) seeping out from the upper and lower resin compositions when the resin compositions are laminated and fused, thereby enabling the resin compositions to be more firmly fused to each other by the seeped polyamide resin (A).

In this embodiment, the additive is an amorphous semi-aromatic polyamide resin (B), an organic lubricant, or a viscosity modifier containing a compound having a carboxy group in the molecule (hereinafter, also simply referred to as "viscosity modifier"). The resin composition may contain only one of these, or may contain multiple types. According to the findings of the present inventors, when two or more of the above three types of additives are combined, the effect of improving the interlaminar shear strength is more significant. In addition, when two of the above three types of additives, the amorphous semi-aromatic polyamide resin (B) and an organic lubricant or a viscosity modifier, are combined, the effect of improving the interlaminar shear strength is more significant. The reason why these additives improve the interlaminar shear strength is not clear, but it is presumed that the compatibility between the crystalline semi-aromatic polyamide resin (A) and these additives is high, so that a uniform phase is easily formed, and the interlaminar shear strength is further improved.

(Amorphous Semi-Aromatic Polyamide Resin (B))
The amorphous semi-aromatic polyamide resin (B) (hereinafter, also simply referred to as "polyamide resin (B)") is a semi-aromatic polyamide resin having no crystallinity.

In this specification, the term "polyamide resin has no crystallinity" means that the heat of fusion (ΔH) measured by the same method as for polyamide resin (A) is 5.0 J/g. The heat of fusion (ΔH) of polyamide resin (B) is preferably 1.0 J/g or less, and more preferably 0 J/g.

The polyamide resin (B) preferably has a structure including a component unit (Ba) derived from a dicarboxylic acid and a component unit (Bb) derived from a diamine. The component unit (Ba) derived from a dicarboxylic acid may be a component unit derived from a dicarboxylic acid similar to the dicarboxylic acid exemplified for the component unit (Aa) derived from a dicarboxylic acid in the polyamide resin (A). The component unit (Bb) derived from a diamine may be a component unit derived from a diamine similar to the diamine exemplified for the component unit (Ab) derived from a diamine in the polyamide resin (A).

In addition, it is preferable that the polyamide resin (B) contains at least a component unit derived from isophthalic acid as the component unit (Ba) derived from a dicarboxylic acid. The component unit derived from isophthalic acid can reduce the crystallinity of the polyamide resin (B).

The content of the component units derived from isophthalic acid is preferably 40 mol% or more, more preferably 50 mol% or more, and even more preferably 60 mol% or more, based on the total amount of the component units (Ba) derived from dicarboxylic acids. If the content of the component units derived from isophthalic acid is 40 mol% or more, it is easy to make the polyamide resin (B) amorphous. Although there is no particular limit to the upper limit of the content of the component units derived from isophthalic acid, it can be 100 mol% or less, and preferably 90 mol% or less.

The component unit (Ba) derived from a dicarboxylic acid may further contain a component unit derived from another dicarboxylic acid other than the component unit derived from isophthalic acid, within a range that does not impair the effects of the present invention. Examples of other dicarboxylic acids include aromatic dicarboxylic acids other than isophthalic acid, such as terephthalic acid, 2-methylterephthalic acid, and naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, and alicyclic dicarboxylic acids. The aliphatic dicarboxylic acid and the alicyclic dicarboxylic acid may be the same as the above-mentioned aliphatic dicarboxylic acid and alicyclic dicarboxylic acid, respectively. Among them, aromatic dicarboxylic acids other than isophthalic acid are preferred, and terephthalic acid is more preferred. More specifically, any of the following embodiments is preferred.
Aspect 1: An aspect in which the component units (Ba) derived from a dicarboxylic acid essentially contain only three types of component units derived from isophthalic acid, terephthalic acid, and adipic acid.
Aspect 2: An aspect in which the component units (Ba) derived from a dicarboxylic acid essentially contain only two types of component units derived from isophthalic acid and terephthalic acid.
Incidentally, "substantially contains" means that it is acceptable for the substance to be unavoidably mixed in or for it to be contained in a trace amount that does not affect the physical properties.

In the component units (Ba) derived from dicarboxylic acids, the molar ratio of the component units derived from isophthalic acid to the component units derived from aromatic dicarboxylic acids other than isophthalic acid (preferably terephthalic acid) is preferably isophthalic acid derived component units/aromatic dicarboxylic acids other than isophthalic acid (preferably terephthalic acid) = 55/45 to 100/0 (molar ratio), more preferably 60/40 to 90/10 (molar ratio). If the amount of the component units derived from isophthalic acid is equal to or greater than a certain amount, the polyamide resin (B) tends to be amorphous, and the crystallization rate of the matrix resin is slowed down by the polyamide resin (B) to more fully impregnate the polyamide resin (A), and the interlaminar shear strength of the laminate obtained by laminating and fusing the above resin compositions together tends to be increased.

The diamine-derived component unit (b-1) is preferably a component unit derived from 1,6-diaminohexane.

The polyamide resin (B) may be any of the amorphous polyamide resins described in M. I. Kohan Nylon plastics handbook, Hanser, Munich (1995), pages 377-380.

The polyamide resin (B) may have a glass transition temperature (Tg) of 80°C or higher and 150°C or lower.

The intrinsic viscosity [η] of the polyamide resin (B) measured at a temperature of 25°C in 96.5% sulfuric acid is preferably 0.5 dl/g or more and 1.25 dl/g or less. When the intrinsic viscosity [η] of the polyamide resin (B) is 0.5 dl/g or more, the mechanical strength (toughness, etc.) of the molded body is easily increased, and when it is 1.25 dl/g or less, the fluidity of the resin composition during molding is not easily impaired. From the same viewpoint, the intrinsic viscosity [η] of the polyamide resin (B) is more preferably 0.6 dl/g or more and 1.15 dl/g or less, and even more preferably 0.6 dl/g or more and 1.05 dl/g or less. The intrinsic viscosity [η] can be adjusted by the amount of terminal blocking of the polyamide resin (A), etc.

The content of polyamide resin (B) is preferably 1 part by mass or more and 30 parts by mass or less, more preferably 5 parts by mass or more and 27 parts by mass or less, and even more preferably 10 parts by mass or more and 25 parts by mass or less, when the total mass of the resin components contained in the resin composition is taken as 100 parts by mass. When the content of polyamide resin (B) is 1 part by mass or more, the crystallization rate of the matrix resin is slowed down to more thoroughly impregnate the polyamide resin (A), and the interlaminar shear strength of the laminate obtained by laminating and fusing the resin compositions together tends to be increased. When the content of polyamide resin (B) is 30 parts by mass or less, the tensile strength and Young's modulus of the fiber-reinforced resin composition and the laminate and molded body of the fiber-reinforced resin composition tend to be increased.

(Organic lubricants)
Examples of the organic lubricant include:
Higher aliphatic hydrocarbon lubricants including liquid paraffin, microcrystalline wax, natural paraffin, and synthetic paraffin, etc.
These include fatty acid-based lubricants, such as stearic acid, lauric acid, hydroxystearic acid, and hydrogenated castor oil; metal soaps, which are fatty acid metal salts having 8 or more carbon atoms, such as lead stearate, calcium stearate, and calcium hydroxystearate; long-chain ester waxes, such as montan wax; higher aliphatic alcohol compounds having 12 to 30 carbon atoms; higher aliphatic amide compounds having 12 to 30 carbon atoms; and composite lubricants made by combining these.

Of these, from the viewpoint of further improving the interlaminar shear strength, the organic lubricant is preferably an organic lubricant having an intramolecular lubricant effect. The organic lubricant having an intramolecular lubricant effect preferably contains a metal soap. In other words, from the viewpoint of further improving the interlaminar shear strength, the organic lubricant preferably contains a metal soap.

The metal soap is a salt of a metal and a fatty acid having 8 or more carbon atoms. The fatty acid may be a dicarboxylic acid or an unsaturated carboxylic acid. Examples of the fatty acid include octanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, 12-hydroxystearic acid, behenic acid, montanic acid, sebacic acid, and ricinoleic acid.

Examples of the above metals include lithium, sodium, potassium, magnesium, calcium, barium, zinc and aluminum, as well as mixed metals containing two or more of these.

Specific examples of the metal soap include lithium stearate, magnesium stearate, calcium stearate, barium stearate, zinc stearate, calcium 12-hydroxystearate, zinc 12-hydroxystearate, magnesium 12-hydroxystearate, aluminum 12-hydroxystearate, barium 12-hydroxystearate, lithium 12-hydroxystearate, calcium behenate, zinc behenate, magnesium behenate, lithium behenate, calcium montanate, zinc montanate, magnesium montanate, aluminum montanate, lithium montanate, calcium laurate, barium laurate, zinc laurate, calcium ricinoleate, barium ricinoleate, zinc ricinoleate, zinc octylate, aluminum octylate, zinc myristate, and zinc palmitate. These may be used alone or in combination.

Of these, from the viewpoint of further improving the interlaminar shear strength, it is preferable that the metal soap has an aliphatic chain that contains a hydroxyl group. More specifically, from the viewpoint of further improving the interlaminar shear strength, it is preferable that the metal soap contains calcium 12-hydroxystearate.

The content of the organic lubricant (preferably metal soap) is preferably 0.1 parts by mass or more and 10.0 parts by mass or less, more preferably 0.5 parts by mass or more and 8.0 parts by mass or less, and even more preferably 1.0 parts by mass or more and 5.0 parts by mass or less, when the total mass of the resin components contained in the resin composition is taken as 100 parts by mass. When the content of the organic lubricant is 0.1 parts by mass or more, the polyamide resin (A) can be more sufficiently impregnated, and the interlaminar shear strength of the laminate obtained by laminating and fusing the resin compositions together can be further increased. When the content of the organic lubricant is 10.0 parts by mass or less, the tensile strength and Young's modulus of the fiber-reinforced resin composition and the laminate and molded product of the fiber-reinforced resin composition tend to be excellent.

(Viscosity modifier)
The viscosity modifier is a compound having a carboxy group in the molecule. The viscosity modifier may be any compound having a carboxy group in the molecule, and the number of carboxy groups in the molecule is not particularly limited.

Examples of viscosity modifiers include monocarboxylic acids, dicarboxylic acids, and polycarboxylic acids having three or more carboxyl groups. The upper limit of the number of carboxyl groups in the polycarboxylic acids is not particularly limited, but can be eight or less.

Examples of the monocarboxylic acid include aliphatic monocarboxylic acids having 2 to 30 carbon atoms, aromatic monocarboxylic acids, and alicyclic monocarboxylic acids. The aromatic monocarboxylic acids and alicyclic monocarboxylic acids may have a substituent in the cyclic structure portion.

Examples of the aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid.

Examples of the aromatic monocarboxylic acids include benzoic acid, toluic acid, naphthalene carboxylic acid, methylnaphthalene carboxylic acid, and phenyl acetic acid.

Examples of the dicarboxylic acids include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid.

Examples of polycarboxylic acids having three or more carboxy groups include aromatic polycarboxylic acids such as trimellitic acid and pyromellitic acid.

The content of the viscosity modifier is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, more preferably 0.05 parts by mass or more and 5.0 parts by mass or less, and even more preferably 0.1 parts by mass or more and 3.0 parts by mass or less, when the total mass of the resin components contained in the resin composition is taken as 100 parts by mass. When the content of the viscosity modifier is 0.01 parts by mass or more, the polyamide resin (A) can be more sufficiently impregnated, and the interlaminar shear strength of the laminate obtained by laminating and fusing the resin compositions together can be further increased. When the content of the viscosity modifier is 10.0 parts by mass or less, the tensile strength and Young's modulus of the fiber-reinforced resin composition and the laminate and molded body of the fiber-reinforced resin composition tend to be further improved.

[Other ingredients]
The resin composition may contain other components that can be contained in the polyamide resin composition in the matrix resin. Examples of the other components include crystal nucleating agents, flame retardants, corrosion resistance improvers, drip prevention agents, ion scavengers, elastomers (rubbers), antistatic agents, mold release agents, antioxidants (phenols, amines, sulfurs, phosphorus compounds, etc.), heat stabilizers (lactone compounds, vitamin E compounds, hydroquinones, copper halides, iodine compounds, etc.), light stabilizers (benzotriazoles, triazines, benzophenones, benzoates, hindered amines, oxanilides, etc.), other polymers (polyolefins, olefin copolymers such as ethylene-propylene copolymers, ethylene-1-butene copolymers, olefin copolymers such as propylene-1-butene copolymers, polystyrene, polyamides, polycarbonates, polyacetals, polysulfones, polyphenylene oxides, fluororesins, silicone resins, LCPs, etc.).

[Production and shape of resin composition]
The resin composition may contain a plurality of reinforcing fibers oriented in one direction and a matrix resin impregnated into the reinforcing fibers, and may be in the form of a thin-film fiber-reinforced resin (UD sheet) in which a plurality of reinforcing fibers arranged in one direction are impregnated with the resin composition, a thin-film fiber-reinforced resin (cross sheet) in which a woven fabric of a plurality of reinforcing fibers arranged in one direction is impregnated with the resin composition, or a pellet-shaped resin composition (LFT).

The content of the reinforcing fibers relative to the total mass of the resin composition can be, for example, 10% by mass or more and 90% by mass or less. The content of the matrix resin relative to the total mass of the resin composition can be 10% by mass or more and 90% by mass or less. The content of the reinforcing fibers relative to the total volume of the resin composition can be 10% by volume or more and 70% by volume or less.

(UD sheet)
The UD sheet can be produced by impregnating the reinforcing fibers with the matrix resin by a known method.

For example, the reinforcing fibers that have been opened and aligned in one direction can be simultaneously brought into contact with an impregnation roll whose surface has been coated with the molten matrix resin, the impregnation roll is rotated, and the reinforcing fibers are moved along the rotation direction, thereby impregnating the reinforcing fibers with the matrix resin.

Alternatively, the method of resin impregnation is not limited to the above method, and may involve immersing the reinforcing fibers in the molten matrix resin.

After impregnating the carbon fibers with resin, the resin is cooled and solidified to obtain a UD sheet in which the matrix resin is impregnated into multiple reinforcing fibers that are oriented in one direction.

The content of the reinforcing fibers relative to the total mass of the UD sheet is preferably 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 75% by mass or less, even more preferably 30% by mass or more and 65% by mass or less, and particularly preferably 35% by mass or more and 60% by mass or less. The content of the matrix resin relative to the total mass of the UD sheet is preferably 20% by mass or more and 80% by mass or less, more preferably 25% by mass or more and 70% by mass or less, even more preferably 35% by mass or more and 70% by mass or less, and particularly preferably 40% by mass or more and 65% by mass or less.

The content of the reinforcing fibers relative to the total volume of the UD sheet (fiber volume content: Vf) is preferably 10% by volume or more and 70% by volume or less, more preferably 15% by volume or more and 60% by volume or less, and even more preferably 20% by volume or more and 60% by volume or less.

The thickness of the UD sheet is not particularly limited, but is preferably 1 μm or more and 500 μm or less, more preferably 5 μm or more and 400 μm or less, and even more preferably 5 μm or more and 300 μm or less.

The manner in which the UD sheet is used is not particularly limited, and a single UD sheet may be used as is, or multiple UD sheets may be used as a laminate. The UD sheet may also be cut appropriately and used in the form of a tape.

The UD sheets can be stacked and fused together to form a laminate by methods such as laser fusion and press molding. The laminate may be fused or adhered to the surface of another molded body. In this case, the UD sheet laminate may be sequentially fused to the surface of the other molded body by laser, or the UD sheet laminate may be fused to the surface of the other molded body by methods such as insert molding. Alternatively, the UD sheets may be wrapped around a mandrel and fused together to form a pipe made of the UD sheet laminate.

When forming a laminate by fusing with a laser, the resin composition preferably contains a pigment in the matrix resin to increase the absorption efficiency of the laser and further increase the fusing efficiency. The pigment can be a known pigment or dye. The pigment and dye are preferably pigments and dyes that have a higher absorbance at the same wavelength as the wavelength of the irradiated laser, specifically, pigments and dyes with a maximum absorption wavelength of 300 nm or more and 3000 nm or less are preferable, pigments and dyes with a maximum absorption wavelength of 500 nm or more and 2000 nm or less are more preferable, and pigments and dyes with a maximum absorption wavelength of 700 nm or more and 1500 nm or less are even more preferable. On the other hand, from the viewpoint of allowing more freedom in selecting the wavelength of the laser, the pigments and dyes are preferably pigments and dyes (or combinations thereof) that can absorb a wider range of wavelengths, specifically, black pigments and dyes (or combinations thereof) are preferable, more preferably containing carbon-based pigments, and even more preferably containing carbon black.

The content of the pigment and dye may be such that it sufficiently increases the laser absorption efficiency and does not significantly affect other properties such as the strength of the laminate. For example, the content of the carbon black is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more and 5% by mass or less, based on the total mass of the resin composition.

(Cross seat)
The cloth sheet can be produced by weaving the reinforcing fibers by a known method and impregnating the woven fabric with the matrix resin, for example by immersing the reinforcing fibers in molten matrix resin.

The content of the reinforcing fibers relative to the total mass of the cross sheet is preferably 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 75% by mass or less, even more preferably 30% by mass or more and 65% by mass or less, and particularly preferably 35% by mass or more and 60% by mass or less. The content of the matrix resin relative to the total mass of the UD sheet is preferably 20% by mass or more and 80% by mass or less, more preferably 25% by mass or more and 70% by mass or less, even more preferably 35% by mass or more and 70% by mass or less, and particularly preferably 40% by mass or more and 65% by mass or less.

The content of the reinforcing fibers relative to the total volume of the cross sheet (fiber volume content: Vf) is preferably 10% by volume or more and 70% by volume or less, more preferably 15% by volume or more and 60% by volume or less, and even more preferably 20% by volume or more and 60% by volume or less.

The thickness of the cross sheet is not particularly limited, but is preferably 1 μm or more and 500 μm or less, more preferably 5 μm or more and 400 μm or less, and even more preferably 5 μm or more and 300 μm or less.

The manner in which the cross sheet is used is not particularly limited, and a single cross sheet may be used as is, or multiple cross sheets may be used as a laminate. The cross sheet may also be appropriately cut into a tape shape for use.

(LFT)
LFT is a core-sheath type long fiber-containing pellet containing carbon fiber and semi-aromatic polyamide, and can be produced by impregnating the reinforcing fiber with the matrix resin by a known method to obtain a strand, and then cutting the strand to a predetermined length.

The content of the reinforcing fibers relative to the total mass of the LFT is preferably 10% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 90% by mass or less, and even more preferably 40% by mass or more and 90% by mass or less. The content of the matrix resin relative to the total mass of the LFT is preferably 10% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 80% by mass or less, and even more preferably 10% by mass or more and 60% by mass or less.

The content of the reinforcing fibers relative to the total volume of the LFT is preferably 10% by volume or more and 70% by volume or less, more preferably 15% by volume or more and 60% by volume or less, and even more preferably 20% by volume or more and 60% by volume or less.

The length of the LFT is not particularly limited, but is preferably 3 mm or more and 100 mm or less, and more preferably 5 mm or more and 50 mm or less.

LFT may be molded into a desired shape by injection molding, press molding, or the like. It may also be molded into a desired shape by direct molding, in which the manufacturing and molding of LFT are carried out continuously.

[Other embodiments]
It should be noted that each of the above-described embodiments shows an example of the present invention, and the present invention is not limited to the above-described embodiments. Needless to say, various other embodiments are possible within the scope of the concept of the present invention.

[Application]
The applications of the resin molded article are not limited, but it is useful as a reinforcing material for other structural materials.

Specific examples of applications of the resin molded articles include primary structural materials including main wings, vertical and horizontal stabilizers, etc.; secondary structural materials including ailerons, rudders and elevators, etc.; interior materials including seats and tables, etc.; parts and components of general flying objects such as airplanes and helicopters, including power units, hydraulic cylinders, and composite brakes, etc.; rocket parts and components including nozzle cones and motor cases, etc.; satellite parts and components including antennas, structures, solar panels, battery cases and telescopes, etc.; machine parts and components including frames, shafts, rollers, leaf springs, machine tool heads, robot arms, transport hands and synthetic fiber pots, etc.; high-speed rotating body parts including centrifuge rotors and uranium enrichment cylinders, etc. Components, parabolic antennas, battery components, radar, audio speaker cones, computer parts, printer parts, electronic and electrical components including personal computer cases and tablet cases, frame parts, semi-structural parts, exterior panel parts, interior and exterior parts, power units, other equipment - hydraulic cylinders, brakes, battery cases, drive shafts, engine parts, spoilers, racing car bodies, crash cones, chairs, tablets, telephone covers, under covers, side covers, transmission covers, battery trays, rear steps, spare tire containers, automobile and motorcycle components including bus body walls and truck body walls, interior materials, floor panels, ceiling panels, linear motor car bodies, bullet trains railroad car bodies, window wipers, trolleys and seats, and other vehicle parts and components; ship hulls including yachts, cruisers and boats, ship parts and components and bodies including masts, rudders, propellers, hard sails, screws, military ship fuselages, submarine fuselages and deep sea exploration vessels, and other ship parts and components; pressure vessel parts and components including actuators, cylinders, cylinders, hydrogen tanks, CNG tanks and oxygen tanks, and other scientific equipment parts and components including stirring blades, pipes, tanks, pit floors and plant piping, and other wind power generation parts and components including blades, skins, skeletal structures and de-icing systems, and other parts for X-ray diagnostic equipment, wheelchairs, artificial bones, prosthetic legs and arms, crutches, nursing care assistance devices and robots (power assist suits), walking machines and nursing care beds. civil engineering and infrastructure parts and components, including CF composite cables, concrete reinforcing members, guardrails, bridges, tunnel walls, hoods, cables, tension rods, strand rods, and flexible pipes; offshore oil field drilling parts and components, including marine risers, flexible jumpers, flexible risers, and drilling risers; sports and leisure goods, including fishing rods, reels, golf clubs, tennis rackets, badminton rackets, skis, ski poles, snowboards, ice hockey sticks, snowmobiles, archery equipment, kendo bamboo swords, baseball bats, swimming diving boards, sports equipment for the disabled, and sports helmets. ) Bicycle parts including frames, disc wheels, rims, handlebars and saddles, daily necessities including glasses, bags, umbrellas and ballpoint pens, and other industrial parts and materials including plastic pallets, containers, logistics materials, resin molds, furniture, umbrellas, helmets, pipes, scaffolding boards, safety shoes, protectors, fuel cell covers, drone blades, frames, jigs and jig frames.

The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to the description of the examples.

The intrinsic viscosity [η] of the polyamide resin was calculated by dissolving 0.5 g of the polyamide resin in 50 ml of a 96.5% sulfuric acid solution, measuring the flow time of the obtained solution at 25° C.±0.05° C. using an Ubbelohde viscometer, and calculating the intrinsic viscosity [η]=η/(C(1+0.205η)) based on the formula:
[η]: Intrinsic viscosity (dl/g)
ηSP: specific viscosity C: sample concentration (g/dl)
t: number of seconds for sample solution to flow (seconds)
t0: Number of seconds (seconds) for blank sulfuric acid to flow
ηSP=(t-t0)/t0

The melting point Tm, glass transition temperature Tg, and heat of fusion (ΔH) of the polyamide resin were measured using a differential scanning calorimeter (DSC220C type, manufactured by Seiko Instruments Inc.). Specifically, about 5 mg of polyamide resin was sealed in an aluminum pan for measurement and set in the differential scanning calorimeter. Then, it was heated from room temperature to 350°C at 10°C/min. In order to completely melt the resin, it was held at 360°C for 3 minutes and then cooled to 30°C at 10°C/min. After leaving it at 30°C for 5 minutes, it was heated a second time to 360°C at 10°C/min. The temperature (°C) of the endothermic peak in this second heating was taken as the melting point (Tm) of the polyamide resin, and the transition point corresponding to the glass transition was taken as the glass transition temperature (Tg). The heat of fusion ΔH was calculated from the area of the endothermic peak of crystallization during the first heating process in accordance with JIS K7122.

1. Synthesis and preparation of materials 1-1. Synthesis of polyamide resin 1-1-1. Synthesis of crystalline polyamide resin (A-1) (PA6TDT) 3655g (22.0 mol) of terephthalic acid, 1312g (11.3 mol) of 1,6-diaminohexane, 1312g (11.3 mol) of 2-methyl-1,5-pentanediamine, 5.5g (5.2×10 ⁻² mol) of sodium hypophosphite monohydrate, and 640ml of distilled water were placed in an autoclave with a capacity of 1L and substituted with nitrogen. Stirring was started at 190°C, and the internal temperature of the autoclave was raised to 250°C over 3 hours. At this time, the internal pressure of the autoclave was raised to 3.03 MPa. After continuing the reaction for 1 hour, the mixture was released into the air from a spray nozzle installed at the bottom of the autoclave and the low condensate was extracted. The extracted low condensate was cooled to room temperature (23 ° C), pulverized to a particle size of 1.5 mm or less with a pulverizer, and dried at 110 ° C for 24 hours. The moisture content of the obtained low condensate was 4100 ppm, and the intrinsic viscosity [η] was 0.15 dl / g. Next, this low condensate was placed in a tray-type solid-phase polymerization apparatus, and after nitrogen replacement, the temperature was raised to 180 ° C over about 1 hour and 30 minutes. Then, the reaction was allowed to proceed for 1 hour and 30 minutes, and the temperature was lowered to room temperature (23 ° C). Then, in a twin-screw extruder with a screw diameter of 30 mm and L / D = 36, melt polymerization was performed at a barrel setting temperature of 330 ° C, a screw rotation speed of 200 rpm, and a resin supply rate of 10 Kg / h to obtain a crystalline polyamide resin (A-1).

The resulting crystalline polyamide resin (A-1) had an intrinsic viscosity [η] of 0.9 dl/g, a melting point Tm of 300°C, and a heat of fusion (ΔH) of 42 J/g.

1-1-2. Synthesis of crystalline polyamide resin (A-2) (PA6T6I) 2774g (16.7 mol) of terephthalic acid, 1196g (7.2 mol) of isophthalic acid, 2800g (24.1 mol) of 1,6-diaminohexane, 36.6g (0.3 mol) of benzoic acid, 5.7g (5.4×10 ⁻² mol) of sodium hypophosphite monohydrate and 545g of distilled water were placed in an autoclave with a capacity of 1L and substituted with nitrogen. Stirring was started at 190°C, and the internal temperature of the autoclave was raised to 250°C over 3 hours. At this time, the internal pressure of the autoclave was raised to 3.03 MPa. After continuing the reaction for 1 hour, the mixture was released into the air from a spray nozzle installed at the bottom of the autoclave and the low condensate was extracted. The extracted low condensate was cooled to room temperature (23 ° C), pulverized to a particle size of 1.5 mm or less with a pulverizer, and dried at 110 ° C for 24 hours. The moisture content of the obtained low condensate was 4100 ppm, and the intrinsic viscosity [η] was 0.15 dl / g. Next, this low condensate was placed in a tray-type solid-phase polymerization apparatus, and after nitrogen replacement, the temperature was raised to 180 ° C over about 1 hour and 30 minutes. Then, the reaction was allowed to proceed for 1 hour and 30 minutes, and the temperature was lowered to room temperature (23 ° C). Then, in a twin-screw extruder with a screw diameter of 30 mm and L / D = 36, melt polymerization was performed at a barrel setting temperature of 330 ° C, a screw rotation speed of 200 rpm, and a resin supply rate of 10 Kg / h to obtain a crystalline polyamide resin (A-2).

The resulting crystalline polyamide resin (A-2) had an intrinsic viscosity [η] of 1.0 dl/g, a melting point Tm of 330°C, and a heat of fusion (ΔH) of 51 J/g.

1-1-3. Synthesis of amorphous polyamide resin (B-1) (PA6I6T) 1390g (8.4 mol) of terephthalic acid, 2581g (15.5 mol) of isophthalic acid, 2800g (24.1 mol) of 1,6-diaminohexane, 109.5g (0.9 mol) of benzoic acid, 5.7g (5.4×10 ⁻² mol) of sodium hypophosphite monohydrate and 545g of distilled water were placed in an autoclave with a capacity of 1L and substituted with nitrogen. Stirring was started at 190°C, and the internal temperature of the autoclave was raised to 250°C over 3 hours. At this time, the internal pressure of the autoclave was raised to 3.03 MPa. After continuing the reaction for 1 hour, the mixture was discharged into the air from a spray nozzle installed at the bottom of the autoclave and the low condensate was extracted. The extracted low condensate was cooled to room temperature (23 ° C), pulverized to a particle size of 1.5 mm or less with a pulverizer, and dried at 110 ° C for 24 hours. The moisture content of the obtained low condensate was 4100 ppm, and the intrinsic viscosity [η] was 0.15 dl / g. Next, this low condensate was placed in a tray-type solid-phase polymerization apparatus, and after nitrogen replacement, the temperature was raised to 180 ° C over about 1 hour and 30 minutes. Then, the reaction was allowed to proceed for 1 hour and 30 minutes, and the temperature was lowered to room temperature (23 ° C). Then, in a twin-screw extruder with a screw diameter of 30 mm and L / D = 36, melt polymerization was performed at a barrel setting temperature of 330 ° C, a screw rotation speed of 200 rpm, and a resin supply rate of 10 Kg / h to obtain an amorphous polyamide resin (B-1).

The resulting amorphous polyamide resin (B-1) had an intrinsic viscosity [η] of 0.65 dl/g, a glass transition temperature (Tg) of 125°C, and a heat of fusion (ΔH) of 0 J/g.

1-2. Preparation of reinforcing fibers As a carbon fiber bundle, T700SC (manufactured by Toray Industries, Inc., number of filaments: 24,000) was prepared.

1-3. Preparation of additives 1-3-1. Amorphous semi-aromatic polyamide resin The amorphous polyamide resin (B-1) synthesized above was used.

1-3-2. Organic lubricant Metal soap (calcium 12-hydroxystearate: CS-6CP, manufactured by Nitto Kasei Kogyo Co., Ltd.) was used.

1-3-3. Viscosity modifier
Benzoic acid was used.

1-4. Other Components As a flow lubricant, Hiwax 100P (low molecular weight polyethylene, molecular weight 900) manufactured by Mitsui Chemicals, Inc. was used.

2. Preparation of UD sheet 2-1. Preparation of polyamide resin composition A crystalline semi-aromatic polyamide resin, additives (amorphous semi-aromatic polyamide resin, organic lubricant or viscosity modifier) or the other components described above were kneaded in the ratios shown in Tables 1 and 2 in a 30 mmφ vented twin-screw extruder with a barrel temperature set to 335°C, extruded, and then pelletized in a pelletizer to obtain pellets of a polyamide resin composition.

2-2. Preparation of UD sheet Carbon fiber bundles were opened and aligned so as to be oriented in one direction. The above polyamide resin composition, which had been heated to a temperature 10°C higher than the melting point Tm of the crystalline semi-aromatic polyamide resin in a mold and brought into a molten state, was brought into contact with the carbon fiber bundles and impregnated. The temperature of the mold was also set to a temperature 10°C higher than the melting point Tm of the crystalline semi-aromatic polyamide resin.

After impregnation and cooling, the UD sheets obtained contained 63% by mass of carbon fiber and 37% by mass of polyamide resin composition relative to the total mass of the UD sheet. The thickness of the obtained UD sheet was 200 μm.

3. Evaluation
3-1. Interlaminar shear strength (ILSS)
The UD sheets were stacked in 11 layers so that the fibers were oriented parallel to each other, and then hot-pressed at 340°C for 3 minutes at 8 MPa, followed by cooling at 15°C for 3 minutes at 8 MPa to obtain a laminate. The thickness of the composite material was 2 mm.

Test pieces measuring 4 mm in width, 12 mm in length, and 2 mm in thickness were prepared from this composite material, and the interlaminar shear strength (ILSS) was measured at 23°C and a test speed of 1 mm/min using an Autograph AG-X manufactured by Shimadzu Corporation in accordance with ASTM D2344.

3-2. Impregnation Carbon fiber bundles (width: 9 mm) were opened and aligned in one direction so as to have a width of 12 mm.

The pellets of the polyamide resin composition prepared above were molded into a 200 μm film by heat pressing for 3 minutes at a temperature 10°C higher than the melting point Tm of the crystalline semi-aromatic polyamide resin using a 200 μm spacer.

The above-mentioned opened and aligned carbon fibers were laid on the obtained film, and pressed for 5 minutes at a temperature 10° C. higher than the melting point Tm of the crystalline semi-aromatic polyamide resin. After the pressing operation, the surface on the carbon fiber side was observed, and the impregnation state of the resin composition was evaluated according to the following criteria.
◯: Resin seepage was observed. ×: Resin seepage was not observed.

Tables 1 to 3 show the types and amounts of each material used in the production of the UD sheet (values when the amount of the polyamide resin composition is 100 parts by mass), the melting point Tm of the crystalline semi-aromatic polyamide resin, the fiber volume content Vf, and the interlaminar shear strength (ILSS) measurement results, and the impregnation evaluation results.

As is clear from Tables 1 to 3, when the matrix resin contains at least one additive selected from the group consisting of crystalline semi-aromatic polyamide resin (A), amorphous semi-aromatic polyamide resin (B), organic lubricants, and viscosity modifiers containing compounds having carboxy groups in the molecule, the impregnation of the matrix resin is improved, and the interlaminar shear strength (ILSS) is increased.

The cylindrical body of the present invention is lightweight and has high interlaminar shear strength when laminated. Therefore, the cylindrical body of the present invention can be suitably used as various reinforcing materials, cylindrical bodies, and molded bodies.

Claims (11)

A plurality of arranged reinforcing fibers;
A crystalline semi-aromatic polyamide resin (A) (excluding polyamide resins composed of diamine-derived structural units and dicarboxylic acid-derived structural units, in which 70 mol % or more of the diamine-derived structural units are derived from metaxylylenediamine and 70 mol % or more of the dicarboxylic acid-derived structural units are derived from adipic acid) ,
and at least one additive selected from the group consisting of an organic lubricant and a viscosity modifier containing a compound having a carboxy group in the molecule;
The additive satisfies at least one of the following conditions (1) to (3):
Fiber reinforced resin composition.
Condition (1): The additive contains the organic lubricant, and the organic lubricant is a metal soap.
Condition (2): The additive contains the organic lubricant, and the content of the organic lubricant is 0.1 parts by mass or more and 10.0 parts by mass or less when the total mass of the resin components contained in the fiber-reinforced resin composition is 100 parts by mass.
Condition (3): The additive includes the viscosity modifier, the viscosity modifier is a monocarboxylic acid, and the content of the viscosity modifier is 0.01 parts by mass or more and 10.0 parts by mass or less when the total mass of the resin components contained in the fiber-reinforced resin composition is 100 parts by mass. The crystalline semi-aromatic polyamide resin (A) contains a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine,
The component unit (Aa) derived from a dicarboxylic acid includes a component unit (Aa1) derived from at least one selected from the group consisting of terephthalic acid and naphthalenedicarboxylic acid.
The fiber reinforced resin composition according to claim 1. The content of the component unit (Aa1) is more than 20 mol % and not more than 100 mol % based on the total number of moles of the component unit (Aa) derived from a dicarboxylic acid.
The fiber reinforced resin composition according to claim 2. The additive satisfies at least one of the conditions (2) to (3).
The fiber reinforced resin composition according to any one of claims 1 to 3. The additive satisfies the condition (3).
The fiber reinforced resin composition according to claim 4. The additive satisfies the condition (1),
The fiber reinforced resin composition according to any one of claims 1 to 5 , wherein the metal soap contains a hydroxy group. The fiber reinforced resin composition according to claim 5 , wherein the monocarboxylic acid is benzoic acid or acetic acid. The fiber-reinforced resin composition according to any one of claims 1 to 7 , wherein the plurality of reinforcing fibers are oriented and arranged in one direction. The fiber reinforced resin composition according to any one of claims 1 to 7 , wherein the plurality of reinforcing fibers are woven together. A laminate obtained by laminating the fiber-reinforced resin composition according to any one of claims 1 to 9 and welding the laminated layers together. A molded article obtained by molding the fiber-reinforced resin composition according to any one of claims 1 to 9 .