prepreg

Abstract

This prepreg includes 50 wt% to 70 wt% of carbon fiber bundles which result from bundling a plurality of continuous carbon fibers and which have been oriented in one direction, and 30 wt% to 50 wt% of a matrix resin, wherein the matrix resin is a polyphenylene sulfide (PPS) resin composition comprising (A) a PPS resin and (B) a poly-N-vinylamide resin. According to the present invention, it is possible to obtain a fiber-reinforced polyphenylene sulfide resin composition base material that has excellent coatability and heat resistance and has excellent mechanical properties.

Description

Prepreg

[0001] The present invention relates to a thermoplastic prepreg using a polyphenylene sulfide resin composition.

[0002] Polyarylene sulfides (hereinafter abbreviated as PAS), typified by polyphenylene sulfide (hereinafter sometimes abbreviated as PPS), have excellent properties as engineering plastics, such as excellent heat resistance, barrier properties, moldability, chemical resistance, electrical insulation, and moist heat resistance, and are used in various electrical and electronic parts, machine parts, automotive parts, etc.

[0003] Polyarylene sulfide can be used as a fiber-reinforced plastic to further improve its mechanical properties while taking advantage of its excellent properties. Fiber-reinforced plastics come in a variety of forms, including injection molding materials in which short fibers are mixed into polyarylene sulfide, and fiber-reinforced resin substrates such as woven fabrics using long fibers and sheet-like prepregs in which unidirectionally oriented fibers are impregnated with polyarylene sulfide. The latter long fibers are preferred for structural components, such as aircraft, which require particularly high mechanical properties.

[0004] However, conventional polyphenylene sulfide resins are essentially brittle materials with low toughness, and in the case of fibers such as carbon fibers that barely expand when heated, the residual stress during molding is large, and even a slight disturbance in the fiber orientation can cause the molded product to curve or crack, often resulting in insufficient composite properties such as bending strength and interlaminar shear strength. Furthermore, in order to improve the mechanical properties and heat resistance of fiber-reinforced polyphenylene sulfide resin substrates, various prepregs have been developed using polyphenylene sulfide resin compositions obtained by alloying polyphenylene sulfide resin with other polymers.

[0005] Patent Document 1 discloses a prepreg having a high glass transition temperature and a high bending strain at high temperatures, which is obtained by alloying a polyphenylene sulfide resin with a heat-resistant polymer.

[0006] Patent Document 2 discloses a prepreg using a polyphenylene sulfide resin composition containing a polyphenylene sulfide resin and a resin containing 0.03 to 3.5 mass % of nitrogen atoms.

[0007] Patent Document 3 discloses a prepreg having excellent impact resistance, which is obtained by using a polyphenylene sulfide resin composition in which a specific rubber component is blended with a polyphenylene sulfide resin.

[0008] Patent Document 4 discloses a prepreg in which the amount of halogen contained in a sizing agent for reinforcing fibers and the amount of inorganic chlorine contained in polyphenylene sulfide are controlled, thereby achieving good adhesion between the reinforcing fibers and the polyphenylene sulfide resin.

[0009] International Publication No. 2020 / 196109 Japanese Patent Application Laid-Open No. 2021-152126 Japanese Patent Publication No. 7-45626 Japanese Patent Application Laid-Open No. 2016-188291

[0010] Patent Document 1 discloses a fiber-reinforced polyphenylene sulfide resin composition substrate with a high glass transition temperature obtained by alloying polyphenylene sulfide resin with a heat-resistant polymer, but does not specifically disclose short beam shear strength. Furthermore, the heat-resistant polymers used in the polyphenylene sulfide resin composition all have high chemical resistance, which could reduce the paintability of molded articles made using prepregs.

[0011] Patent Document 2 discloses a fiber-reinforced polyphenylene sulfide resin composition substrate having high rigidity and high toughness by alloying polyphenylene sulfide resin with a specific polyamide elastomer. Although the polyphenylene sulfide resin composition used is specifically described, there is no specific disclosure of the properties of molded articles using the prepreg, such as heat resistance, short beam shear strength, and paintability.

[0012] Patent Document 3 discloses a prepreg having high rigidity and high toughness by alloying a polyphenylene sulfide resin with a specific polyamide elastomer. Although the polyphenylene sulfide resin composition used is specifically described, there is no specific disclosure of the properties of molded articles using the prepreg, such as heat resistance, short beam shear strength, or paintability.

[0013] In Patent Document 4, the adhesiveness at the interface is good and high strength is obtained even in short beam shear strength, but no specific description is given regarding heat resistance or paintability.

[0014] However, even in the prepregs using the polyphenylene sulfide resin compositions of the embodiments described in these publications, there is a risk that the adhesion of paint may be insufficient or the heat resistance may be insufficient due to the excellent chemical resistance property of the polyphenylene sulfide resin composition.

[0015] An object of the present invention is to provide a fiber-reinforced polyphenylene sulfide resin composition substrate that is excellent in paintability, heat resistance, and mechanical properties.

[0016] The present invention, which aims to solve the above problems, has any one of the following configurations. [1] A prepreg containing 50% by weight to 70% by weight of unidirectionally oriented carbon fiber bundles formed by bundling a plurality of continuous carbon fibers, and 30% by weight to 50% by weight of a matrix resin, wherein the matrix resin is a PPS (polyphenylene sulfide) resin composition comprising the following (A) and (B): (A) PPS resin; and (B) poly-N-vinylamide resin. [2] The prepreg according to [1], wherein the weight-average molecular weight of (A) is 50,000 to 150,000. [3] The prepreg according to [1] or [2], wherein the PPS resin composition comprises 99.9 to 70% by weight of (A) and 0.1 to 30% by weight of (B), where the total of (A) and (B) is 100% by weight. [4] The prepreg according to any one of [1] to [3], wherein (B) forms island phases in the PPS resin composition. [5] The prepreg according to any one of [1] to [4], wherein the number average particle diameter of (B) in the PPS resin composition is 1 nm or more and 10 μm or less. [6] The prepreg according to any one of [1] to [5], wherein (B) is a poly-N-vinylamide resin having a glass transition temperature Tg of 140°C or more and 200°C or less. [7] The prepreg according to any one of [1] to [6], wherein (B) is at least one poly-N-vinylamide resin selected from poly-N-vinylpyrrolidone resin, poly-N-vinylacetamide resin, and poly-N-vinylcaprolactam resin. [8] The prepreg according to any one of [1] to [7], wherein, when the prepreg is formed into a unidirectional fiber-reinforced plastic molded article, the glass transition temperature of the unidirectional fiber-reinforced plastic molded article is 111°C or more and 200°C or less. [9] The prepreg according to any one of [1] to [8], wherein, when the prepreg is formed into a unidirectional fiber-reinforced plastic molded article, the evaluation rank is 0 to 2 according to the following paint adhesion measurement method. Measurement method for paint adhesion classification: Cross-cut method in accordance with JIS K5600-5-6

[10] The prepreg according to any one of [1] to [9], wherein the contact angle of the prepreg with water is 65 to 85°.

[11] When the prepreg is made into a unidirectional fiber reinforced plastic molded article, the unidirectional fiber reinforced plastic molded article has a short beam shear strength of 70 MPa or more. Prepreg according to any one of [1] to

[10] .

[0017] According to the present invention, a fiber-reinforced polyphenylene sulfide resin composition substrate having excellent paintability, heat resistance, and mechanical properties can be obtained.

[0018] An embodiment of the present invention will be described in detail below. The present invention relates to a prepreg containing 50% by weight to 70% by weight of carbon fiber bundles formed by bundling a plurality of continuous carbon fibers and oriented in one direction, and 30% by weight to 50% by weight of a matrix resin, wherein the matrix resin is a PPS (polyphenylene sulfide) resin composition comprising the following (A) and (B): (A) PPS resin; and (B) poly-N-vinylamide resin.

[0019] <Reinforcing fiber bundle> In the present invention, one or more reinforcing fiber bundles each formed by bundling a plurality of continuous single fibers and oriented in one direction are used. Here, "continuous" does not mean a bundle cut to a finite length (several microns to several tens of mm), but a state in which the reinforcing fiber bundle is not cut in the orientation direction.

[0020] The average diameter of a single fiber used in the present invention is preferably 5 to 10 μm.

[0021] The reinforcing fiber bundles are used primarily for the purpose of reinforcing a unidirectional fiber-reinforced plastic molded article, which will be described later. The type of monofilament used in the reinforcing fiber bundles is not particularly limited, and examples include carbon fiber, metal fiber, organic fiber, and inorganic fiber. Two or more of these may be used. By using carbon fiber in the reinforcing fiber bundles, a unidirectional fiber-reinforced plastic molded article that is lightweight yet has high mechanical properties can be obtained.

[0022] The prepreg of the present invention is often expected to function as a reinforcing material, and therefore it is desirable that it exhibit high mechanical properties. In order to exhibit high mechanical properties, it is preferable that it contains carbon fibers as reinforcing fibers.

[0023] Examples of carbon fibers include polyacrylonitrile (PAN)-based carbon fibers made from PAN fibers, pitch-based carbon fibers made from petroleum tar or petroleum pitch, cellulose-based carbon fibers made from viscose rayon or cellulose acetate, vapor-grown carbon fibers made from hydrocarbons, graphitized fibers of these, etc. Among these carbon fibers, PAN-based carbon fibers are preferably used because of their excellent balance between strength and elastic modulus.

[0024] Examples of metal fibers include fibers made of metals such as iron, gold, silver, copper, aluminum, brass, and stainless steel.

[0025] Examples of organic fibers include fibers made of organic materials such as aramid, polybenzoxazole (PBO), polyphenylene sulfide, polyester, polyamide, and polyethylene. Examples of aramid fibers include para-aramid fibers, which have excellent strength and elastic modulus, and meta-aramid fibers, which have excellent flame retardancy and long-term heat resistance. Examples of para-aramid fibers include polyparaphenylene terephthalamide fibers and copolyparaphenylene-3,4'-oxydiphenylene terephthalamide fibers, and examples of meta-aramid fibers include polymetaphenylene isophthalamide fibers. As the aramid fiber, para-aramid fibers, which have a higher elastic modulus than meta-aramid fibers, are preferably used.

[0026] Examples of inorganic fibers include fibers made of inorganic materials such as glass, basalt, silicon carbide, and silicon nitride. Examples of glass fibers include E-glass fiber (for electrical use), C-glass fiber (for corrosion resistance), S-glass fiber, and T-glass fiber (high strength, high elastic modulus). Basalt fiber is a fiber made from basalt, a mineral, and has extremely high heat resistance. Basalt generally contains FeO or FeO, which are compounds of iron. ２ 9 to 25% by weight of titanium compounds TiO or TiO ２ However, it is possible to increase the amount of these components in the molten state to form fibers.

[0027] In the present invention, one reinforcing fiber bundle is composed of 1,000 to 50,000 single fibers. Furthermore, when one or more reinforcing fiber bundles are arranged, the total number of filaments (number of single fibers) constituting the reinforcing fiber bundle is preferably 1,000 to 2,000,000. From the viewpoint of productivity, the total number of filaments constituting the reinforcing fiber bundle is more preferably 1,000 to 1,000,000, even more preferably 1,000 to 600,000, and particularly preferably 1,000 to 300,000. The upper limit of the total number of filaments constituting the reinforcing fiber bundle may be determined by taking into consideration a balance between productivity, dispersibility, and ease of handling.

[0028] Examples of the form and orientation of the reinforcing fiber bundle in an embodiment of the present invention include those in which the reinforcing fibers are aligned in one direction, woven fabric (cloth), knitted fabric, braided cord, tow, etc. Among these, it is preferable that the reinforcing fibers are oriented in one direction, since this allows for efficient improvement of the mechanical properties in a specific direction.

[0029] <Polyphenylene sulfide resin composition> It is important to use a polyphenylene sulfide resin composition as the matrix resin in the present invention. Specifically, it is a polyphenylene sulfide resin composition comprising (A) a polyphenylene sulfide resin and (B) a poly-N-vinylamide resin having a glass transition temperature Tg of, for example, 140°C or higher and 200°C or lower. Each of these will be described below.

[0030] <Polyphenylene sulfide resin> The polyphenylene sulfide resin (PPS resin) used in the present invention is a polymer having a repeating unit (1) represented by the following structural formula.

[0031]

[0032] From the viewpoint of heat resistance, a polymer containing 70 mol % or more, and even 90 mol % or more of a polymer containing the repeating unit (1) represented by the above structural formula is preferred. Furthermore, the polymer may be composed of repeating units (2)(a) to (g) having the following structures in a range of 10 to 30 mol % or less of the repeating units other than the repeating unit (1).

[0033]

[0034] A polyphenylene sulfide copolymer partially having such a structure has a low melting point, and therefore such a resin composition is advantageous in terms of moldability.

[0035] The weight-average molecular weight of the (A) polyphenylene sulfide resin used in the present invention is preferably 50,000 or more. The lower limit of the weight-average molecular weight of the (A) polyphenylene sulfide resin is 50,000, preferably 50,000 or more, and more preferably 60,000 or more. The upper limit of the weight-average molecular weight of the (A) polyphenylene sulfide resin is 150,000 or less, preferably 120,000 or less, and more preferably 110,000 or less. When the weight-average molecular weight of the (A) polyphenylene sulfide resin is within the above-mentioned preferred range, a fiber-reinforced substrate having better mechanical properties tends to be obtained. If the weight-average molecular weight is less than 50,000, the mechanical properties of the polyphenylene sulfide resin composition itself and the adhesion to the reinforcing fibers tend to decrease. On the other hand, when the weight average molecular weight of the polyphenylene sulfide resin (A) is greater than 150,000, the melt viscosity becomes significantly large, which reduces the impregnation ability with the reinforcing fibers, and it tends not to be possible to obtain a fiber-reinforced substrate that is well impregnated with the polyphenylene sulfide resin composition.

[0036] The weight average molecular weight in the present invention is a value calculated in terms of polystyrene using gel permeation chromatography (GPC) manufactured by Senshu Scientific Co., Ltd.

[0037] In the fiber-reinforced thermoplastic resin substrate of the present invention, the ash content of the (A) polyphenylene sulfide resin is preferably 0.001 wt% or more and 0.30 wt% or less. The upper limit of the ash content is 0.30 wt%, preferably 0.25 wt%, more preferably 0.20 wt% or less, and even more preferably 0.10 wt%. When the ash content of the (A) polyphenylene sulfide resin is within the above-mentioned preferred range, a fiber-reinforced thermoplastic resin substrate with better mechanical properties tends to be obtained. When the ash content of the (A) polyphenylene sulfide resin is less than 0.001 wt%, the toughness of the polyphenylene sulfide resin itself and its adhesion to carbon fibers tend to decrease. On the other hand, when the ash content of the (A) polyphenylene sulfide resin is greater than 0.30 wt%, the mechanical properties of the molded article obtained using the prepreg decrease, which is not preferable. Examples of means for adjusting the ash content within the above range include acid treatment and hot water treatment in the process for producing the (A) polyphenylene sulfide resin. The ash content of the polyphenylene sulfide resin (A) is measured by the method described below.

[0038] From the viewpoint of improving adhesion to carbon fibers, the (A) polyphenylene sulfide resin of the present invention preferably has a carboxyl group content of 5 to 25 μmol / g. The lower limit of the carboxyl group content is preferably 5 μmol / g or more, more preferably 8 μmol / g or more, and even more preferably 10 μmol / g. The upper limit of the carboxyl group content is preferably 25 μmol / g or less, and even more preferably 20 μmol / g or less. If the carboxyl group content of the (A) polyphenylene sulfide resin is less than 5 μmol / g, the interaction and adhesion with carbon fibers tend to decrease, which is undesirable. On the other hand, if the carboxyl group content of the (A) polyphenylene sulfide resin exceeds 25 μmol / g, the amount of volatile components increases during processing, which is undesirable. The carboxyl group content of the (A) polyphenylene sulfide resin is a value calculated using a Fourier transform infrared spectrometer (FT-IR).

[0039] Examples of methods for introducing a carboxyl group into the polyphenylene sulfide resin (A) include a method of copolymerizing a polyhalogenated aromatic compound containing a carboxyl group, and a method of adding a compound containing a carboxyl group, such as maleic anhydride or sorbic acid, and reacting it with the polyphenylene sulfide resin (A) while melt-kneading.

[0040] <Poly N-vinylamide Resin> The N-vinylamide resin constituting the resin composition of the present invention preferably has a glass transition temperature Tg of 140°C or higher and 200°C or lower. If the glass transition temperature Tg is higher than 200°C, the compatibility with polyphenylene sulfide resin and the adhesion between the polyphenylene sulfide resin composition and carbon fiber tend to decrease. On the other hand, if the glass transition temperature Tg is lower than 140°C, the heat resistance of the polyphenylene sulfide resin composition tends to decrease, which tends to limit the environment and conditions in which the polyphenylene sulfide resin composition can be used as a prepreg.

[0041] The N-vinylamide resin is preferably a homopolymer or copolymer obtained by polymerizing an N-vinylamide monomer, more preferably a homopolymer, and even more preferably at least one selected from poly(N-vinylpyrrolidone), poly(N-vinylacetamide), and poly(N-vinylcaprolactam) resins.

[0042] As the N-vinylamide monomer, a monomer represented by the following chemical formula is typically preferred.

[0043]

[0044] (In the formula, R １ represents hydrogen or a methyl group. ２ and R ３ are each independently a hydrogen atom, a methyl group, or an ethyl group. ２ and R ３ are bonded to form a ring having 3 to 5 carbon atoms.

[0045] R ２ and R ３When R are independent of each other, examples thereof include N-vinylacetamide, N-methyl-N-vinylacetamide, N-vinylformamide, N-methyl-N-vinylformamide, and N-vinylpropionamide. ２ and R ３ When these are bonded to form a ring having 3 to 5 carbon atoms, examples thereof include cyclic N-vinylamides such as N-vinylpyrrolidone, N-vinylpiperidone, and N-vinyl lactams such as N-vinylcaprolactam, and one or more of these may be used as necessary. When a polymer is produced using a cyclic N-vinylamide, the polymer has a cyclic amide structure in the branched chain. A preferred example of a cyclic N-vinylamide is N-vinylpyrrolidone, and in this case, polyvinylpyrrolidone is produced.

[0046] There are no particular limitations on the polymerization method for the N-vinylamide resin, but it is generally obtained by radical polymerization in an aqueous solution or organic solvent using a radical generator such as an organic peroxide, an azo compound, or hydrogen peroxide.

[0047] <Polyphenylene sulfide resin composition> As described above, the polyphenylene sulfide resin composition of the present invention is a polyphenylene sulfide resin composition comprising (A) a polyphenylene sulfide resin and (B) a poly-N-vinylamide resin.

[0048] As described above, the blending ratio of (A) polyphenylene sulfide resin and (B) poly N-vinylamide resin (e.g., a poly N-vinylamide resin having a glass transition temperature of 140°C or higher and 200°C or lower) in the present invention is preferably (A) / (B) = 99.9 to 70 wt% / 0.1 to 30 wt%, more preferably (A) / (B) = 99 to 75 wt% / 1 to 25 wt%, and even more preferably (A) / (B) = 95 to 80 wt% / 5 to 20 wt%. When (A) / (B) is within the above preferred range, a fiber-reinforced substrate with superior mechanical properties and paintability tends to be obtained. Dispersion of the poly N-vinylamide resin in the polyphenylene sulfide resin composition improves the interfacial strength with the reinforcing fibers, and the hydrophilicity of the poly N-vinylamide resin is thought to improve adhesion to paint. If the amount of the poly-N-vinylamide resin (B) added to the polyphenylene sulfide resin composition is less than 0.1% by weight, the adhesion between the polyphenylene sulfide resin composition and the reinforcing fibers tends to decrease.

[0049] On the other hand, when the amount of the poly-N-vinylamide resin (B) added to the polyphenylene sulfide resin composition is greater than 30% by weight, the polyphenylene sulfide resin composition has a reduced solvent resistance and is more susceptible to moisture absorption due to the increased content of the hydrophilic poly-N-vinylamide resin. Furthermore, the mechanical properties of the prepreg impregnated with the polyphenylene sulfide resin composition after moisture absorption tend to be reduced.

[0050] It is also preferable that the (B) poly-N-vinylamide resin forms an island phase within the polyphenylene sulfide resin composition. The polyphenylene sulfide resin composition used in the present invention has excellent toughness in addition to the excellent heat resistance, chemical resistance, and barrier properties inherent to the (A) polyphenylene sulfide resin. In order to exhibit such properties, it is preferable that the (A) polyphenylene sulfide resin forms a sea phase (continuous phase or matrix) and the (B) poly-N-vinylamide resin forms an island phase (dispersed phase).

[0051] Furthermore, the number average particle diameter of (B) is preferably 1 nm or more and 10 μm or less. The number average particle diameter of (B) is preferably 10 μm or less, more preferably 1 μm or less, and even more preferably 500 nm or less. The lower limit of the number average particle diameter of (B) is preferably 1 nm or more from the viewpoint of productivity. If the number average particle diameter of (B) exceeds 10 μm, the toughness-improving effect is significantly impaired, which is undesirable. By forming a continuous phase of (A) polyphenylene sulfide resin, the excellent chemical resistance and flame retardancy of (A) polyphenylene sulfide resin can be significantly reflected in the properties of the resulting composition. The presence of (B) poly-N-vinylamide resin in the polyphenylene sulfide resin composition as island phases with an average particle diameter in the above-mentioned preferred range is thought to improve the interfacial strength with the reinforcing fibers, and also improve adhesion to paint due to the hydrophilicity of the poly-N-vinylamide resin and the polarity of the amide group.

[0052] The number average particle diameter referred to here is the number average particle diameter obtained by molding an ASTM No. 4 test piece at a molding temperature that is 20°C above the melting peak temperature of (A) polyphenylene sulfide resin, cutting thin pieces of 0.1 μm or less from the center of the test piece at -20°C in the cross-sectional direction of the dumbbell piece, and observing the pieces at a magnification of 10,000 to 20,000 times using a Hitachi H-7100 transmission electron microscope (resolution (particle image) 0.38 nm, magnification 500,000 to 600,000 times). First, the maximum diameter and minimum diameter of each of the dispersed portions of (B) poly-N-vinylamide resin were measured, the average value was taken as the dispersed particle diameter, and then the average value was calculated.

[0053] The polyphenylene sulfide resin composition impregnated into the reinforcing fiber bundles in the present invention is typically obtained by melt-kneading. Representative examples of melt-kneading machines include those commonly known in the art, such as single-screw or twin-screw extruders, Banbury mixers, kneaders, and mixing rolls, where the resin composition is fed into the melting peak temperature of the resin composition plus 5 to 100°C. The order in which the raw materials are mixed is not particularly limited. Any of the following methods may be used: blending all raw materials and then melt-kneading them as described above; blending some raw materials and then melt-kneading them as described above, followed by blending and melt-kneading the remaining raw materials; or blending some raw materials and then melt-kneading them using a side feeder while melt-kneading them in a single-screw or twin-screw extruder. Furthermore, minor additive components can also be added to the pelletized resin composition prior to molding after the other components have been blended using the methods described above.

[0054] <Prepreg> The prepreg according to the present invention is a prepreg containing 50% by weight to 70% by weight of reinforcing fiber bundles formed by bundling a plurality of continuous carbon fibers and oriented in one direction, and 30% by weight to 50% by weight of the polyphenylene sulfide resin composition comprising the above-mentioned (A) and (B). By containing 50% by weight or more of reinforcing fiber bundles, the mechanical properties of the prepreg can be improved. A practical maximum weight content of reinforcing fibers is 70%; if it is more than this, the amount of polyphenylene sulfide resin composition decreases, and the resin composition does not reach every corner of the prepreg, which is undesirable.

[0055] The prepreg according to the present invention preferably has a thickness of 0.1 to 1.5 mm. If the thickness is 0.1 mm or more, the strength of the molded article obtained using the prepreg can be improved. 0.2 mm or more is more preferable. On the other hand, if the thickness is 1.5 mm or less, it is easier to impregnate the reinforcing fibers with the polyphenylene sulfide resin composition. 1 mm or less is more preferable, 0.7 mm or less is even more preferable, and 0.6 mm or less is even more preferable.

[0056] The prepreg according to the present invention preferably contains 20% by volume or more and 65% by volume or less of reinforcing fiber bundles, assuming the volume of the entire prepreg to be 100% by volume. By containing 20% ​​by volume or more of reinforcing fiber bundles, the strength of a molded article obtained using the prepreg can be further improved. 30% by volume or more is more preferable, and 40% by volume or more is even more preferable. On the other hand, by containing 65% by volume or less of reinforcing fiber bundles, the reinforcing fiber bundles can be more easily impregnated with the thermoplastic resin. The volume content of the reinforcing fiber bundles is more preferably 60% by volume or less, and even more preferably 55% by volume or less. The volume content can be adjusted to a desired range by adjusting the amounts of reinforcing fiber bundles and polyphenylene sulfide resin composition added.

[0057] The weight content (Wf) and volume content (Vf) of the reinforcing fibers in the prepreg are calculated by measuring the mass W0 of the prepreg, decomposing and eluting the polyphenylene sulfide resin composition of the prepreg according to the sulfuric acid decomposition method described in JIS K7075-1991, measuring the mass W1 of the remaining reinforcing fibers after washing and drying, and then calculating them using the following formulas (h) and (i): Wf (weight %) = W1 / W0 × 100 ... (h) Vf (volume %) = (W1 / ρf) / {W1 / ρf + (W0 - W1) / ρr} × 100 ... (i) ρf: density of the reinforcing fibers (g / cm ３ ρr: density of polyphenylene sulfide resin composition (g / cm ３ )

[0058] Furthermore, the prepreg of the present invention can be impregnated in a desired manner depending on its intended use and purpose. Examples include prepregs with higher impregnation properties, semi-pregs with half-impregnation properties, and fabrics with low impregnation properties. Generally, a substrate with higher impregnation properties is preferred because it allows for the production of molded articles with excellent mechanical properties in a short molding time.

[0059] The contact angle of the prepreg according to the present invention with water is preferably 65 to 85°. When the contact angle is within the above preferred range, it is believed that the interfacial strength with the reinforcing fibers is improved, and the hydrophilicity of the poly-N-vinylamide resin and the polarity of the amide group improve adhesion to the paint. A contact angle greater than 85° is undesirable because it impairs adhesion to the paint. A contact angle less than 65° reduces the solvent resistance of the polyphenylene sulfide resin composition and makes it more susceptible to moisture absorption. Furthermore, the mechanical properties of the prepreg impregnated with the polyphenylene sulfide resin composition after moisture absorption tend to deteriorate.

[0060] The contact angle of the prepreg according to the present invention with water was measured in an atmosphere of 23°C and 50% RH using an automatic contact angle meter DMo-701 manufactured by Kyowa Interface Science Co., Ltd. in accordance with a method in accordance with JIS R3257-1999.

[0061] <Method for Producing Prepreg> The prepreg according to the present invention can be obtained by impregnating continuous reinforcing fibers with a polyphenylene sulfide resin composition.

[0062] Examples of methods for impregnating continuous reinforcing fibers with the polyphenylene sulfide resin composition include a film method in which a film-like polyphenylene sulfide resin composition is melted and pressurized to impregnate a reinforcing fiber bundle with the polyphenylene sulfide resin composition; a commingle method in which a fibrous polyphenylene sulfide resin composition is blended with a reinforcing fiber bundle, and then the fibrous polyphenylene sulfide resin composition is melted and pressurized to impregnate the reinforcing fiber bundle with a thermoplastic resin; a powder method in which a powdered polyphenylene sulfide resin composition is dispersed into gaps between fibers in a reinforcing fiber bundle, and then the powdered polyphenylene sulfide resin composition is melted and pressurized to impregnate the reinforcing fiber bundle with the polyphenylene sulfide resin composition; and a pultrusion method in which a reinforcing fiber bundle is immersed in a molten polyphenylene sulfide resin composition and then pressurized to impregnate the reinforcing fiber bundle with the polyphenylene sulfide resin composition. The powder method and pultrusion method are preferred, and the powder method is more preferred, since they allow the production of a wide variety of prepregs with various thicknesses and fiber volume contents.

[0063] Among the powder methods, it is also possible to produce the composite by a powder method in which a reinforcing fiber bundle is passed through a suspension in which powdered polyphenylene sulfide resin is dispersed in water using a poly-N-vinylamide resin as a surfactant, the powdered polyphenylene sulfide resin composition adhering to the reinforcing fiber bundle is melted, and pressure is applied to impregnate the reinforcing fiber bundle with the polyphenylene sulfide resin composition.

[0064] <Method for manufacturing fiber-reinforced plastic molded body> The fiber-reinforced plastic molded body of the present invention is formed by laminating a plurality of prepregs in an arbitrary configuration and then applying heat and / or pressure. In particular, a molded body formed by aligning the reinforcing fiber bundles of the prepregs in one direction is called a unidirectional fiber-reinforced plastic molded body.

[0065] Examples of methods for applying heat and / or pressure include a press molding method in which prepregs laminated in an arbitrary configuration are placed in a mold or on a press plate, and then the mold or press plate is closed and pressurized, an autoclave molding method in which a fiber-reinforced plastic molded body laminated in an arbitrary configuration is placed in an autoclave and pressurized and heated, a bagging molding method in which a fiber-reinforced plastic molded body laminated in an arbitrary configuration is wrapped in a film or the like and heated in an oven while reducing the internal pressure and applying pressure at atmospheric pressure, and a wrapping tape method in which a fiber-reinforced plastic molded body laminated and molded in an arbitrary configuration is wrapped in tape while applying tension and heated in an oven, etc. In particular, the molding method of pressing using a mold is preferably used because it produces molded products with few voids and excellent appearance quality.

[0066] Examples of press molding methods that can be used include hot pressing, in which a prepreg is placed in a mold in advance, pressurized and heated while the mold is clamped, and then, while the mold is still clamped, the prepreg is cooled by cooling the mold to obtain a molded product, and stamping molding, in which the prepreg is heated in advance to a temperature above the melting point of the thermoplastic resin using a heating device such as a far-infrared heater, a heating plate, a high-temperature oven, or a dielectric heater, and the thermoplastic resin is melted and softened and then placed on a mold that will become the lower surface of the mold, and the mold is then closed to clamp, followed by pressurized cooling. Of these, stamping molding is preferred from the perspective of shortening the molding cycle and increasing productivity.

[0067] <Method for manufacturing composite> To manufacture a composite in which the fiber-reinforced plastic molded article of the present invention is integrated with a separate member, integration molding such as insert molding or outsert molding, or bonding methods with excellent productivity such as heat correction treatment, heat welding, vibration welding, or ultrasonic welding, or integration using an adhesive can be performed. Such a composite is preferably a composite in which the unidirectional fiber-reinforced plastic molded article of the present invention is at least partially joined to a molded article containing a thermoplastic resin.

[0068] There are no particular limitations on the molded article containing a thermoplastic resin to be integrated with the fiber-reinforced plastic molded article of the present invention, and examples thereof include resin materials and molded articles thereof, metal materials and molded articles thereof, inorganic materials and molded articles thereof, etc. Among these, resin materials and molded articles thereof are preferred in terms of adhesive strength with the fiber-reinforced plastic molded article of the present invention.

[0069] The matrix resin used in the molded article containing a thermoplastic resin integrated with the fiber-reinforced plastic molded article of the present invention may be the same type of resin as the fiber-reinforced plastic molded article of the present invention, or a different type of resin. To further increase the adhesive strength, the same type of resin is preferable. When different types of resin are used, it is more preferable to provide a resin layer at the interface.

[0070] <Unidirectional Fiber Reinforced Plastic Molded Article> Next, various properties of a unidirectional fiber reinforced plastic molded article produced from the obtained prepreg by the above-described method will be described.

[0071] It is important that when a coating material described below is applied to the unidirectional fiber reinforced plastic molding of the present invention, the coating material adhesion is classified into a range of 0 to 2 according to the cross-cut method in accordance with JIS K5600-5-6.

[0072] The adhesion of the coating material in the present invention was evaluated by a cross-cut method in accordance with JIS K5600-5-6. Specifically, the method described below was used. A one-component primer consisting of Planet PP Primer K-3 and Planet Thinner #302 (manufactured by Origin Electric Co., Ltd.) in a 2:1 ratio was sprayed onto the unidirectional fiber-reinforced plastic molded article in the present invention, followed by drying at 75°C for 30 minutes. A two-component paint consisting of Planet PH-4, Polyhard P-2, and Planet Thinner #742 (manufactured by Origin Electric Co., Ltd.) in a 4:1:2 ratio was then sprayed onto the unidirectional fiber-reinforced plastic molded article in the present invention, followed by drying at 75°C for 30 minutes. The primer and coating material had film thicknesses of approximately 15 μm and 20 μm, respectively. Vertical and horizontal cuts were made in the coating film at 1 mm intervals, creating a total of 100 grid squares. Thereafter, adhesive tape (product number KT-SP3209, manufactured by Cortec Co., Ltd.) was applied over the cross-hatched pattern, and the adhesive tape was then peeled off. The coating film remaining on the molded piece was observed and evaluated for adhesion using the six-level classification (0, 1, 2, 3, 4, 5) of JIS K5600-5-6 described below.

[0073] Unidirectional fiber-reinforced plastic moldings with better paintability tend to be obtained when the paint adhesion classification of the unidirectional fiber-reinforced plastic molding is in the range of 0 to 2. The polyphenylene sulfide resin composition is impregnated into the reinforcing fiber bundles at a certain interfiber distance, and a dense sea-island structure is formed between the fibers, with the sea phase being (A) polyphenylene sulfide resin and the island phase being (B) poly-N-vinylamide resin (for example, a poly-N-vinylamide resin having a glass transition temperature Tg of 140°C or higher and 200°C or lower), and this is thought to improve the interfacial adhesion between the unidirectional fiber-reinforced plastic molding and the paint, in other words, to improve the paintability.

[0074] When the paint adhesion of a unidirectional fiber-reinforced plastic molded product is classified as 3 to 5, this means that 15% or more of the paint peels off after testing according to JIS K5600-5-6, and the paint adhesion is poor. When poly-N-vinylamide resin is dispersed in a polyphenylene sulfide resin composition with a number average particle diameter of 10 μm or more, the poly-N-vinylamide resin, which has high adhesion to paint, tends to disperse coarsely, resulting in reduced paintability. Furthermore, in the case of a unidirectional fiber-reinforced plastic molded product using polyphenylene sulfide resin alone, only polyphenylene sulfide resin, which has high chemical resistance, is present, and therefore paint adhesion tends to be reduced.

[0075] The structure of a fiber-reinforced plastic molded body is established by the adhesive strength between the fiber and resin, or the adhesive strength between the laminated layers. Therefore, in order for a fiber-reinforced plastic molded body to perform as a structural material, the adhesive strength between the laminated layers, i.e., short beam shear strength (interlaminar shear strength), is one of its important properties.

[0076] The short beam shear strength of the unidirectional fiber-reinforced plastic molding of the present invention is preferably 70 MPa or more. The higher the short beam shear strength, the higher the peel resistance when shear deformation occurs in the unidirectional fiber-reinforced plastic molding. In order to increase the short beam shear strength, it is necessary to improve the adhesion between the fiber and the resin, improve the shear strength of the resin, and achieve a homogeneous fiber dispersion that can utilize the shear strength of the resin. If the shear strength of the polyphenylene sulfide resin composition used in the present invention can be utilized and adhesion to the fiber is also high, the short beam shear strength can reach 70 MPa, which is preferable. A more preferable value is 80 MPa or more. A practical upper limit of the short beam shear strength is preferably 100 MPa.

[0077] The test to measure short beam shear strength is conducted in accordance with JIS K 7078-1991. For the test, a fiber-reinforced plastic specimen was used, with the number of layers adjusted to a thickness h (mm) of 1.8 to 2.2 mm, processed to a width b (mm) of 10 mm and a length L (mm) of approximately 15 mm, with a bending span distance of approximately 10 mm. The exact dimensions of the length L (mm) and span distance depend on the thickness h (mm) of the specimen, and are 7h (mm) and 5h (mm), respectively.

[0078] The glass transition temperature of the unidirectional fiber-reinforced plastic molded article of the present invention, as measured by the DMA (Dynamic Mechanical Analysis) method (bending mode), is preferably 111°C or higher, more preferably 120°C or higher, and even more preferably 125°C or higher. The upper limit of the glass transition temperature of the unidirectional fiber-reinforced plastic molded article, as measured by the DMA method (bending mode), is preferably 240°C, more preferably 230°C or lower, and even more preferably 200°C or lower. When the glass transition temperature of the unidirectional fiber-reinforced plastic molded article, as measured by the DMA method (bending mode), is lower than 111°C, the mechanical properties of the unidirectional fiber-reinforced plastic molded article at high temperatures tend to decrease, and a unidirectional fiber-reinforced plastic molded article having better heat resistance cannot be obtained. When the upper limit of the glass transition temperature of the unidirectional fiber-reinforced plastic molded article, as measured by the DMA method (bending mode), is within the above-mentioned preferred range, a unidirectional fiber-reinforced plastic molded article having excellent adhesion to reinforcing fiber bundles and well impregnated with the polyphenylene sulfide resin composition can be obtained.

[0079] To measure the glass transition temperature of a unidirectional fiber-reinforced plastic molded article impregnated with the polyphenylene sulfide resin composition of the present invention, dynamic viscoelasticity measurement, specifically DMA (flexural mode), can be used. For the DMA (flexural mode), a unidirectional fiber-reinforced plastic molded article is cut into a rectangular column measuring 20 mm in length, 12 mm in width, and 2 mm in thickness. Measurements can be performed using a Seiko Instruments DMS6100 in flexural mode at a measurement temperature of 30°C to 250°C, a heating rate of 2°C / min, a measurement frequency of 1 Hz (sine wave mode), a strain amplitude of 10 μm, and the temperature is measured at the intersection of two straight lines extending from the storage modulus curve. The first straight line is drawn by extending the straight line before the initial sharp drop in storage modulus toward the higher temperature side, and the second straight line is drawn by extending the straight line between the intermediate line after the initial sharp drop in storage modulus toward the lower temperature side. A vertical line was drawn at the intersection of the two lines on the temperature axis of the abscissa, and this temperature was taken as the glass transition temperature. The temperature showing the peak in this graph was taken as the glass transition temperature.

[0080] In the unidirectional fiber-reinforced plastic molded article of the present invention, the heat resistance and paintability can be improved by making the number average particle diameter of the (B) poly-N-vinylamide resin component that forms the island phase in the polyphenylene sulfide resin composition that forms the sea-island structure smaller than the distance between reinforcing fibers represented by the following formula: z = y - 2r (z: distance between reinforcing fibers, y: distance between the centers of reinforcing fibers, r: fiber radius).

[0081] The present invention will be explained in more detail below by way of examples, but the present invention is not limited to these examples.

[0082] In the examples and comparative examples, the following polyphenylene sulfide resin, poly-N-vinylamide resin, additives, and reinforcing fiber bundles were used.

[0083] [Polyphenylene sulfide resin: Reference Example 1] A 70-liter autoclave equipped with a stirrer was charged with 8,267.37 g (70.00 mol) of 47.5% sodium hydrosulfide, 2,957.21 g (70.97 mol) of 96% sodium hydroxide, 11,434.50 g (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 2,583.00 g (31.50 mol) of sodium acetate, and 10,500 g of ion-exchanged water, and the mixture was gradually heated to 245°C over approximately 3 hours at atmospheric pressure while passing nitrogen through it. After distilling off 14,780.1 g of water and 280 g of NMP, the reaction vessel was cooled to 160°C. The amount of water remaining in the system per mole of the charged alkali metal sulfide was 1.06 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide released was 0.02 mole per mole of the charged alkali metal sulfide.

[0084] Next, 10,235.46 g (69.63 mol) of p-dichlorobenzene and 9.00 g (91.00 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. While stirring at 240 rpm, the temperature was raised to 238 ° C at a rate of 0.6 ° C / min. After 95 minutes of reaction at 238 ° C, the temperature was raised to 270 ° C at a rate of 0.8 ° C / min. After 100 minutes of reaction at 270 ° C, the mixture was cooled to 250 ° C at a rate of 1.3 ° C / min while injecting 1,260 g (70 mol) of water over 15 minutes. The mixture was then cooled to 200 ° C at a rate of 1.0 ° C / min, and then rapidly cooled to near room temperature.

[0085] The contents were removed and diluted with 26,300 g of NMP. The solvent and solids were filtered through a sieve (80 mesh), and the resulting particles were washed with 31,900 g of NMP and filtered. These were washed several times with 56,000 g of ion-exchanged water and filtered, and then washed with 70,000 g of a 0.05 wt % aqueous acetic acid solution and filtered. After washing with 70,000 g of ion-exchanged water and filtering, the resulting hydrous polyphenylene sulfide particles were dried with hot air at 80 ° C. and then dried under reduced pressure at 120 ° C. The weight-average molecular weight of the resulting polyphenylene sulfide resin was 70,000. This was designated PPS-1 resin.

[0086] [Polyphenylene sulfide resin: Reference Example 2] An autoclave equipped with a stirrer was charged with 6.005 kg (25 mol) of sodium sulfide nonahydrate, 0.205 kg (2.5 mol) of sodium acetate, and 5 kg of NMP. The temperature was gradually increased to 205°C while nitrogen was passed through, and 3.6 liters of water was distilled off. Next, the reaction vessel was cooled to 180°C, and then 3.719 kg (25.3 mol) of 1,4-dichlorobenzene and 3.7 kg of NMP were added. The vessel was sealed under nitrogen and heated to 270°C. The reaction was carried out at 270°C for 2.5 hours. After cooling, the reaction product was washed five times with warm water and then added to 10 kg of NMP heated to 100°C. The mixture was stirred for approximately 1 hour, filtered, and then washed several times with hot water. This was poured into 25 liters of an aqueous acetic acid solution of pH 4 heated to 90°C, and after stirring for about 1 hour, it was filtered and washed with ion-exchanged water of about 90°C until the pH of the filtrate reached 7, and then dried under reduced pressure at 80°C for 24 hours. The weight-average molecular weight of the resulting polyphenylene sulfide resin was 48,000. This was designated PPS-2 resin.

[0087] [Poly N-vinylamide resin] PVP: Poly N-vinylpyrrolidone, K-85 manufactured by Nippon Shokubai Co., Ltd., glass transition temperature 173°C. PVC: A solid obtained by vacuum drying an alcohol solution of poly N-vinylcaprolactam, "Ruviscol Plus" (registered trademark) manufactured by BASF Japan Ltd. at 100°C for 12 hours was used. The glass transition temperature was 173°C. PVA: A solid obtained by vacuum drying an aqueous solution of poly N-vinylacetamide, GE191-103 manufactured by Resonac Corporation at 100°C for 12 hours was used. The glass transition temperature was 185°C.

[0088] [Other resins] PEI: polyetherimide, "Ultem" (registered trademark) 1000, manufactured by Sabic, glass transition temperature 220°C PES: polyethersulfone, "Sumikaexcel" (registered trademark) 3600G, manufactured by Sumitomo Chemical Co., Ltd., glass transition temperature 225°C m-PPE: modified polyphenylene ether, "Iupiace" (registered trademark) YPX100L, manufactured by Mitsubishi Chemical Corporation, glass transition temperature 211°C BF: ethylene-glycidyl methacrylate copolymer, "Bondfast" (registered trademark) E-GMA-MA BF-7L, manufactured by Sumitomo Chemical Co., Ltd., glass transition temperature -33°C

[0089] [Additives] D-1: 3-isocyanatepropyltriethoxysilane: KBE9007, manufactured by Shin-Etsu Chemical Co., Ltd.

[0090] [Reinforcing fiber bundle] CF-1: Carbon fiber (CF: carbon fiber) bundle (manufactured by Toray Industries, Inc., product name T700S-12K)

[0091] [Polymer Molecular Weight Measurement] The molecular weight of the polyphenylene sulfide resin (A) used in the present invention was calculated in terms of polystyrene by gel permeation chromatography (GPC), a type of size exclusion chromatography (SEC). The GPC measurement conditions are as follows: Apparatus: Ultra-high temperature GPC apparatus SSC-7100 manufactured by Senshu Scientific Co., Ltd. Column name: Column GPC3506 manufactured by Senshu Scientific Co., Ltd. Eluent: 1-chloronaphthalene Detector: Differential refractive index detector Column temperature: 210°C Pre-thermostat temperature: 250°C Pump thermostat temperature: 50°C Detector temperature: 210°C Flow rate: 1.0 mL / min Sample injection volume: 300 μL (sample concentration: approximately 0.2 wt%)

[0092] [Paint Adhesion] The prepregs (width 50 mm × thickness 0.08 mm, unidirectional substrate) obtained from each Example and Comparative Example were laminated and press-molded in the 0° direction to a thickness of 2 mm to obtain unidirectional fiber-reinforced plastic molded articles. These molded articles were then cut into rectangular prisms measuring 40 mm wide × 40 mm long × 2 mm thick to prepare samples. Paint adhesion was evaluated using these samples using the cross-cut method in accordance with JIS K 5600-5-6.

[0093] The adhesion rating is as follows: 0: The edges of the cuts are completely smooth and there is no peeling at any of the grid squares. 1: Small peeling of the coating at the intersections of the cuts. Not more than 5% of the cross-cuts are clearly affected. 2: The coating has peeled along the edges of the cuts and / or at the intersections. Not more than 5% but not more than 15% of the cross-cuts are clearly affected. 3: The coating has partially or completely peeled heavily along the edges of the cuts and / or partially or completely peeled at various parts of the squares. Not more than 15% but not more than 35% of the cross-cuts are clearly affected. 4: The coating has partially or completely peeled heavily along the edges of the cuts and / or partially or completely peeled at several squares. Not more than 35% of the cross-cuts are clearly affected. 5: Any degree of peeling that cannot be classified as category 4.

[0094] [Measurement of fiber weight content (Wf) and fiber volume content (Vf)] The fiber weight content (Wf) and fiber volume content (Vf) in the prepreg were measured by measuring the mass W0 of the prepreg, then decomposing and eluting the polyphenylene sulfide resin composition in the prepreg according to the sulfuric acid decomposition method described in JIS K7075-1991, measuring the mass W1 of the remaining reinforcing fibers after washing and drying, and calculating them using the following formulas (h) and (i): Wf (wt%) = W1 / W0 × 100 ... (h) Vf (volume%) = (W1 / ρf) / {W1 / ρf + (W0 - W1) / ρr} × 100 ... (i) ρf: density of the reinforcing fibers (g / cm ３ ρr: density of polyphenylene sulfide resin composition (g / cm ３ )

[0095] [Heat Resistance of Unidirectional Fiber-Reinforced Plastic Molded Articles: DMA Method (Bending Mode)] Unidirectional fiber-reinforced plastic molded articles were obtained by laminating and press-molding prepregs (50 mm wide x 0.08 mm thick, unidirectional substrate) obtained from each Example and Comparative Example in a 0° direction to a thickness of 2 mm. These molded articles were then cut into rectangular prisms measuring 12 mm wide x 20 mm long x 2 mm thick. The storage modulus and loss modulus were measured under the following measurement conditions using a Seiko Instruments Inc. dynamic viscoelasticity measuring device (DMS6100). The loss tangent (tan δ) (= loss modulus / storage modulus) was then calculated. A graph of each measurement temperature versus storage modulus was then created. The glass transition temperature was determined as the temperature at the intersection of two extended straight lines representing the change in storage modulus. The linear portion before the initial sharp drop in storage modulus was extended toward the higher temperature side to draw the first straight line. The linear portion of the midpoint after the initial sharp drop in storage modulus was extended toward the lower temperature side to draw the second straight line. A vertical line was drawn at the intersection of the two lines on the temperature axis of the abscissa, and this temperature was taken as the glass transition temperature. The higher the glass transition temperature, the better the heat resistance of the unidirectional fiber reinforced plastic molding. Measurement mode: Bending mode Temperature conditions: First step: Hold at 50°C for 2 minutes, Second step: Heat up from 30°C to 250°C Heating rate: 2°C / min Measurement frequency: 1Hz Minimum tension: 200mN

[0096] [Mechanical properties (short beam shear strength) of unidirectional fiber reinforced plastic molded body] For the short beam shear strength, 12 layers of prepreg were first laminated to form a 250 mm x 250 mm laminate, which was then press molded at 320 °C and 3 MPa to obtain a unidirectional fiber reinforced plastic molded body. Test pieces were then processed and tested in accordance with JIS-K7078-1991. The average value of the measurement results of the stress value, which is the short beam shear strength of five test pieces, was used as the representative value.

[0097] [Contact angle between thermoplastic prepreg and water] In accordance with JIS R3257:1999, a contact angle meter (DMo-701, manufactured by Kyowa Interface Science Co., Ltd.) was used to measure the contact angle of the prepreg with water by dropping a droplet of approximately 1.0 μL of distilled water onto the film in an atmosphere of 23° C. and 50% RH, and measuring the contact angle 30 seconds after contact using the θ / 2 method. The film was cut into 10 cm square pieces, and the arithmetic mean value of contact angles at five points on the same sample was taken as the contact angle with water (°).

[0098] [Examples 1 to 5, Comparative Examples 3 to 6 (Production of Resin Composition Pellets)] The raw materials shown in Table 1, except for the carbon fiber bundles, were dry-blended in the proportions shown in Table 1, and then melt-kneaded using a TEX30α twin-screw extruder (screw diameter 30 mm, L / D = 45, 5 kneading sections, co-rotating fully intermeshing screws) manufactured by The Japan Steel Works, Ltd., equipped with a vacuum vent, at a screw rotation speed of 300 rpm and a discharge rate of 20 kg / hr, with the cylinder temperature set so that the resin temperature at the die discharge was 300°C, and the mixture was pelletized using a strand cutter and subjected to the various evaluations described above. The evaluation results are shown in Table 1.

[0099] Examples 1 to 5, Comparative Examples 1 to 6 (Prepreg Production) Sixteen bobbins wound with carbon fiber bundles were prepared, and the carbon fiber bundles were continuously fed from each bobbin through a yarn guide. The continuously fed carbon fiber bundles were impregnated in an impregnation die with the resin composition obtained by the above-described method, which was supplied in a fixed amount from a loaded feeder. The carbon fibers impregnated with the resin composition in the impregnation die were continuously drawn from the nozzle of the impregnation die using a take-up roll at a drawing speed of 1 m / min. The processing temperature, which is the temperature at which the carbon fiber was drawn, was 340°C. The drawn carbon fiber bundles were passed through a cooling roll to cool and solidify the resin composition, and the prepreg was wound on a winder. The obtained prepreg had a thickness of 0.08 mm, a width of 50 mm, a unidirectionally oriented reinforcing fiber orientation, and a volume content of 60%. The obtained prepreg was subjected to the various evaluations described above. The evaluation results are shown in Table 1.

[0100]

[0101] The results of Examples 1 to 5 and Comparative Examples 1 to 6 will be compared and explained.

[0102] As shown in Table 1, the prepregs of Examples 1 to 5, which were impregnated with a polyphenylene sulfide resin composition consisting of a polyphenylene sulfide resin and a poly-N-vinylamide resin having a Tg of 140°C or higher and 200°C or lower, all received a paint adhesion evaluation rank of 0 to 2, indicating high paint adhesion. The prepregs of Comparative Examples 1 and 2, which used polyphenylene sulfide resin alone, and the prepregs of Comparative Examples 3 to 6, which were obtained using a resin other than poly-N-vinylamide resin having a Tg of 140°C or higher and 200°C or lower, all received a paint adhesion evaluation rank of 3 to 5, indicating low paint adhesion.

[0103] Furthermore, in the unidirectional fiber-reinforced plastic moldings of Examples 1 to 5, the glass transition temperature T1 was 115°C or higher, and the short beam shear strength was 70 MPa or higher, which indicates that the materials have excellent heat resistance and mechanical properties.

[0104] Taking advantage of their excellent properties, the prepreg and molded articles thereof of the present invention can be used in a variety of applications, such as aircraft parts, automobile parts, electrical and electronic parts, building materials, various containers, daily necessities, household goods, and sanitary products. The fiber-reinforced thermoplastic resin substrate and molded articles thereof of an embodiment of the present invention are particularly preferably used for applications requiring impregnation properties, heat aging resistance, and surface appearance, such as aircraft engine peripheral parts, aircraft exterior parts, automobile body parts, vehicle frames, automobile engine peripheral parts, automobile underhood parts, automobile gear parts, automobile interior parts, automobile exterior parts, intake and exhaust system parts, engine cooling water system parts, automotive electrical parts, and electrical and electronic parts. Specifically, the fiber reinforced resin according to the embodiment of the present invention and its molded articles can be used in a wide range of applications, including aircraft engine peripheral parts such as fan blades, aircraft-related parts such as landing gear pods, winglets, spoilers, edges, rudders, elevators, fairings, and ribs, automobile body parts such as various seats, front bodies, underbodies, various pillars, various members, various frames, various beams, various supports, various rails, and various hinges, automobile engine peripheral parts such as engine covers, air intake pipes, timing belt covers, intake manifolds, filler caps, throttle bodies, and cooling fans, and automobile engine parts such as cooling fans, radiator tank tops and bases, cylinder head covers, oil pans, brake piping, fuel piping tubes, and exhaust gas system parts. Automotive gear parts such as car underhood parts, gears, actuators, bearing retainers, bearing cages, chain guides, and chain tensioners; shift lever brackets, steering lock brackets, key cylinders, door inner handles, door handle cowls, interior mirror brackets, air conditioning switches, instrument panels, console boxes, glove boxes, steering wheels, and trim; automotive interior parts such as front fenders, rear fenders, fuel lids, door panels, cylinder head covers, door mirror stays, tailgate panels, license garnishes, roof rails, engine mount brackets, rear garnishes, rear spoilers, trunk lids, rocker moldings, moldings, lamp housings, front grilles,Automotive exterior parts such as mudguards and side bumpers; intake and exhaust system parts such as air intake manifolds, intercooler inlets, turbochargers, exhaust pipe covers, inner bushings, bearing retainers, engine mounts, engine head covers, resonators, and throttle bodies; engine coolant system parts such as chain covers, thermostat housings, outlet pipes, radiator tanks, oil inators, and delivery pipes; automotive electrical parts such as connectors, wire harness connectors, motor parts, lamp sockets, sensor-mounted switches, and combination switches; and electrical and electronic parts such as generators, electric motors, transformers, current transformers, voltage regulators, rectifiers, resistors, inverters, relays, power contacts, switches, circuit breakers, switches, knife switches, multi-pole rods, motor cases, television housings, laptop housings and internal parts, and CRT display housings and internal parts. They are preferably used in printer housings and internal parts, mobile terminal housings and internal parts for mobile phones, mobile personal computers, handheld mobile phones, and other electronic components such as IC and LED compatible housings, capacitor base plates, fuse holders, various gears, various cases, and cabinets, connectors, SMT compatible connectors, card connectors, jacks, coils, coil bobbins, sensors, LED lamps, sockets, resistors, relays, relay cases, reflectors, small switches, power supply parts, coil bobbins, capacitors, variable capacitor cases, optical pickup chassis, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, Si power modules and SiC power modules, semiconductors, liquid crystal displays, FDD carriages, FDD chassis, motor brush holders, transformer members, parabolic antennas, and computer-related parts.

Claims

1. A prepreg containing 50% by weight to 70% by weight of carbon fiber bundles formed by bundling multiple continuous carbon fibers and oriented in one direction, and 30% by weight to 50% by weight of a matrix resin, wherein the matrix resin is a PPS (polyphenylene sulfide) resin composition consisting of the following (A) and (B): (A) PPS resin (B) poly-N-vinylamide resin 2. The prepreg according to claim 1, wherein the weight average molecular weight of (A) is 50,000 or more and 150,000 or less.

3. The prepreg according to claim 1, wherein the PPS resin composition contains 99.9 to 70% by weight of (A) and 0.1 to 30% by weight of (B), with the total of (A) and (B) being 100% by weight.

4. The prepreg according to claim 1, wherein (B) forms an island phase in the PPS resin composition.

5. The prepreg according to claim 1, wherein the number average particle size of (B) in the PPS resin composition is 1 nm or more and 10 μm or less.

6. The prepreg according to claim 1, wherein (B) is a poly-N-vinylamide resin having a glass transition temperature Tg of 140°C or higher and 200°C or lower.

7. The prepreg according to claim 1, wherein (B) is at least one poly-N-vinylamide resin selected from the group consisting of poly-N-vinylpyrrolidone resin, poly-N-vinylacetamide resin, and poly-N-vinylcaprolactam resin.

8. The prepreg according to claim 1, wherein when the prepreg is formed into a unidirectional fiber reinforced plastic molding, the glass transition temperature of the unidirectional fiber reinforced plastic molding is 111°C or higher and 200°C or lower.

9. The prepreg according to claim 1, wherein when the prepreg is formed into a unidirectional fiber reinforced plastic molded article, the evaluation rank according to the following paint adhesion measurement method is 0 to 2. Measurement method for paint adhesion evaluation rank: Cross-cut method in accordance with JIS K5600-5-6 10. The prepreg according to claim 1, wherein the contact angle of the prepreg with water is 65 to 85 degrees.

11. The prepreg according to claim 1, wherein when the prepreg is formed into a unidirectional fiber reinforced plastic molding, the unidirectional fiber reinforced plastic molding has a short beam shear strength of 70 MPa or more.

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