Fiber-reinforced polyamide resin composition molded products

Abstract

To provide a fiber-reinforced polyamide resin composition molding which is excellent in mechanical characteristics, and excellent in fiber dispersibility and moldability and rigidity at the time of water absorption.SOLUTION: A fiber-reinforced polyamide resin composition molding is composed of 5-50 pts.wt. of a reinforcement fiber (A), 40-94.9 pts.wt. of a polyamide resin composition (B) and 0.1-10 pts.wt. of an ammonium salt (C) composed of an aliphatic dicarboxylic acid having 6 to 12 carbon atoms and ammonium, in which a weight average fiber length (Lwa1) of the reinforcement fiber (A) is 0.4-7 mm, the polyamide resin composition (B) is composed of a polyamide resin (B1), a resin (B2) having a reactive functional group and a compound (B3) produced by reaction of (B1) and (B2), and the resin (B2) is dispersed into a particulate form with a number average particle diameter of 10-1,000 nm.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a fiber-reinforced polyamide resin composition molded article containing a polyamide resin composition and reinforcing fibers. [Background technology]

[0002] Molded articles containing reinforcing fibers and polyamide resin compositions are lightweight and have excellent mechanical properties, and are therefore widely used in sporting goods, aerospace, general industrial applications, etc. Examples of reinforcing fibers used in these molded articles include metal fibers such as aluminum fibers and stainless steel fibers, inorganic fibers such as silicon carbide fibers and carbon fibers, and organic fibers such as aramid fibers and polyparaphenylenebenzoxazole (PBO) fibers.

[0003] Furthermore, molded articles containing reinforcing fibers and polyamide resin compositions have excellent light weight and mechanical properties, and are therefore used in fields such as sports components, automotive components, and more recently, exterior components for electronic device housings and home appliances. In particular, parts for sports applications, electronic device housings, and home appliances require even greater weight reduction and thinning, necessitating high fluidity during molding. Furthermore, because they are used as exterior components, the molded article surface must have good appearance quality, particularly high fiber dispersion. Furthermore, molded articles must have sufficient bending strength and impact resistance when dropped or impacted, so molded articles made from molding materials that can exhibit both high appearance quality and mechanical properties and high fluidity that can accommodate weight reduction and thinning are needed. Furthermore, parts for sports applications, electronic device housings, and home appliances require even greater weight reduction and thinning, but it is known that under normal conditions, molded articles can absorb water, resulting in a decrease in rigidity and deflection. Therefore, molded articles that can exhibit rigidity even when absorbing water are needed.

[0004] As a means for improving mechanical properties, there have been proposed fiber-reinforced polyamide resin composition molded articles containing carbon fibers, organic fibers, and a polyamide resin composition, in which the average fiber length and average fiber end-to-end distance of the carbon fibers and the average fiber length and average fiber end-to-end distance of the organic fibers are within specific ranges (see, for example, Patent Document 1), and fiber-reinforced resin compositions containing carbon fibers, a polyamide resin composition, and a resin having a reactive functional group (see, for example, Patent Document 2).

[0005] Furthermore, as a technique for increasing the fluidity during molding of a molded article, a resin composition containing a dendritic polyester in the molded article has been proposed (see, for example, Patent Document 3).

[0006] Furthermore, as a technique for suppressing the water absorption of molded articles, resin compositions containing polyolefin resins or aromatic polyamides in molded articles have been proposed (see, for example, Patent Documents 4 and 5). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2014 / 098103 [Patent Document 2] International Publication No. 2010 / 107022 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-249363 [Patent Document 4] Japanese Patent Application Publication No. 11-140237 [Patent Document 5] Japanese Patent Application Publication No. 2019-151712 Summary of the Invention [Problem to be solved by the invention]

[0008] Patent Documents 1 and 2 describe that, in order to improve impact strength, molded articles obtained by the techniques thereof contain, in addition to carbon fibers, organic fibers and resins having reactive functional groups. Patent Document 3 also describes that fluidity is improved by adding a dendritic polyester to a polyamide resin composition.

[0009] Patent Document 4 describes that the water absorption rate of a molded article is suppressed by adding a polyolefin resin to a polyamide resin composition, and Patent Document 5 describes that the water absorption rate of a molded article is suppressed by using an aromatic polyamide resin with low water absorption rate as a matrix resin.

[0010] However, Patent Document 1 merely describes that the molded article obtained contains carbon fibers and organic fibers, thereby exhibiting high impact strength. Patent Document 1 makes no mention of the fluidity or fiber dispersion of molded articles made from polyamide resin compositions, and the fluidity and fiber dispersion of the resulting molded articles are insufficient. Patent Document 2 also describes that the molded article obtained can exhibit high impact strength by using a resin having a reactive functional group, but this document also makes no mention of the fluidity and fiber dispersion of the molded article. Patent Document 3 also describes that the molded article obtained by the technology contains a dendritic polyester, thereby characterized by high fluidity, but the improvement in fiber dispersion is insufficient.

[0011] Furthermore, the molded articles obtained by the techniques of Patent Documents 4 and 5 contain polyolefin resins or aromatic polyamide resins with low water absorption, and are therefore characterized by high rigidity when absorbing water, but the improvement in fiber dispersion is insufficient.

[0012] As described above, in the prior art, it has not been possible to obtain a fiber-reinforced polyamide resin composition molded article using a polyamide resin composition as a matrix, which has excellent mechanical properties (including bending properties and impact resistance), excellent fiber dispersion in the molded article, and excellent moldability (fluidity) and rigidity upon water absorption (low water absorption), and there has been a demand for the development of such a fiber-reinforced polyamide resin composition molded article.

[0013] In view of the above-mentioned problems of the prior art, the present invention aims to obtain a fiber-reinforced polyamide resin composition molded article that is excellent in mechanical properties (flexural properties, impact resistance), fiber dispersion, moldability, and rigidity upon water absorption, and in particular to provide a molding material therefor. [Means for solving the problem]

[0014] In order to solve the above problems, the present invention mainly has the following configuration. (1) A fiber-reinforced polyamide resin composition molded article comprising 5 to 50 parts by weight of reinforcing fibers (A), 40 to 94.9 parts by weight of a polyamide resin composition (B), and 0.1 to 10 parts by weight of an ammonium salt (C) composed of an aliphatic dicarboxylic acid having 6 to 12 carbon atoms and ammonia, wherein the weight-average fiber length (Lwa1) of the reinforcing fibers (A) is 0.4 to 7 mm, the polyamide resin composition (B) comprises a polyamide resin (B1), a resin (B2) having a reactive functional group, and a compound (B3) produced by the reaction of the polyamide resin (B1) with the resin (B2), and the resin (B2) is dispersed in the form of particles having a number-average particle diameter of 10 to 1,000 nm. (2) A fiber-reinforced polyamide resin composition molded article according to (1), wherein the polyamide resin (B1) contained in the polyamide resin composition (B) forms a continuous phase, the resin (B2) forms a dispersed phase, and the dispersed phase contains fine particles of the compound (B3) having a particle diameter of 1 to 100 nm. (3) The molded article of the fiber-reinforced polyamide resin composition according to (2), wherein the area ratio of the fine particles made of the compound (B3) to the particles made of the resin (B2) is 20% or more. (4) A fiber-reinforced polyamide resin composition molded article according to any one of (1) to (3), wherein the resin (B2) is a resin having at least one reactive functional group selected from an amino group, a carboxyl group, a metal salt of a carboxyl group, an epoxy group, an acid anhydride group, and an oxazoline group. (5) The molded article of a fiber-reinforced polyamide resin composition according to any one of (1) to (4), wherein the resin (B2) is a polyolefin resin. (6) A fiber-reinforced polyamide resin composition molded article according to any one of (1) to (5), wherein the reinforcing fibers (A) contain carbon fibers (A1) and organic fibers (A2), and the amount of the carbon fibers (A1) is 50 to 99 parts by weight and the amount of the organic fibers (A2) is 1 to 50 parts by weight per 100 parts by weight of the total of the carbon fibers (A1) and the organic fibers (A2). (7) The molded article of the fiber-reinforced polyamide resin composition according to (6), wherein the organic fibers (A2) have a weight average fiber length (Lwa2) of 3 to 7 mm. (8) A fiber-reinforced polyamide resin composition molded article according to any one of (1) to (7), wherein the polyamide resin (B1) is a mixture of a polyamide resin (B1a) selected from polyamide 6 and polyamide 66 and one or more polyamide resins (B1b) selected from the group consisting of polyamide 610, polyamide 612, polyamide 11, polyamide 12, polyamide 1010, polyamide 1012, polyamide 9T, and copolymer polyamides containing at least one of these as a constituent component. (9) The fiber-reinforced polyamide resin composition molded article according to (8), wherein the polyamide resin (B1) is a mixture of polyamide 6 resin and polyamide 610 resin. (10) A molded article of the fiber-reinforced polyamide resin composition according to (8) or (9), which has a water absorption rate of 3.0% or less when left for 24 hours in an environment of 80°C x 95% RH. (11) The fiber-reinforced polyamide resin composition molded article according to any one of (6) to (10), wherein the organic fiber (A2) is at least one selected from the group consisting of liquid crystal polyester fiber, polyarylene sulfide fiber, and fluorine fiber. [Effects of the Invention]

[0015] The fiber-reinforced polyamide resin composition molded article of the present invention contains reinforcing fibers and a polyamide resin composition, and therefore has a high reinforcing effect and excellent impact properties. Furthermore, the fiber-reinforced polyamide resin composition molded article of the present invention contains a specific ammonium salt, and therefore has excellent flowability, fiber dispersion, and mechanical properties during molding. Furthermore, by using a specific polyamide resin mixture, it is possible to obtain even better fiber dispersion and excellent rigidity after water absorption in the molded article.

[0016] Such fiber-reinforced polyamide resin composition molded articles are extremely useful for electrical and electronic devices, home appliances, housings, automotive parts, and parts for sports applications. Examples of electrical and electronic device housings and parts include electronic device housings for computers, televisions, video players, DVD players, cameras, audio equipment, etc., as well as connectors, speakers, microphones, headphones, small motors, and computer-related parts. Examples of home appliances include VTR parts, television parts, irons, hair dryers, rice cooker parts, microwave oven parts, acoustic parts, audiovisual equipment parts such as laser discs (registered trademark), compact discs, and DVDs, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, and word processor parts. Examples of optical and precision machinery-related parts include office computer-related parts, telephone-related parts, facsimile-related parts, copier-related parts, binoculars, cameras, and watches.

[0017] Examples of automotive parts and vehicle-related parts include door pads, pillars, console boxes, various motor housings, roof rails, fenders, garnishes, bumpers, door panels, roof panels, hood panels, trunk lids, door mirror stays, spoilers, hood louvers, wheel covers, hubcaps, grill apron cover frames, lamp bezels, door handles, door moldings, rear finishers, wipers, etc. The molded article of the present invention is also suitable as sporting goods and is suitably used for golf-related goods such as golf clubs, shafts, grips, and golf balls, racket sports-related goods such as tennis rackets, tennis balls, badminton rackets and their strings, and badminton shuttlecocks, personal protective equipment for sports such as masks, helmets, breastplates, elbow pads, and knee pads for American football, baseball, softball, etc., shoe-related goods such as soles for sports shoes, fishing tackle-related goods such as fishing rods, reels, and lures, summer sports-related goods such as surfing, winter sports-related goods such as skiing and snowboarding, and other indoor and outdoor sports-related goods. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram showing a cross section of a molding material for a fiber-reinforced polyamide resin composition molded article, in which carbon fibers (A1) enclose organic fibers (A2). [Figure 2] FIG. 2 is a schematic diagram showing a cross section of a molding material for a fiber-reinforced polyamide resin composition molded article, in which organic fibers (A2) enclose carbon fibers (A1). [Figure 3] FIG. 1 is a schematic diagram showing a cross section of a molding material of a fiber-reinforced polyamide resin composition molded product, in which bundles of carbon fibers (A1) and bundles of organic fibers (A2) are present, separated by a boundary. [Figure 4] FIG. 1 is a schematic diagram showing a composite fiber bundle (E) in a form in which component (D) is attached to a fiber bundle consisting of carbon fiber (A1) and organic fiber (A2) in a cross section of a molding material of a fiber-reinforced polyamide resin composition molded product. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described in detail below with reference to embodiments. The present invention provides a fiber-reinforced polyamide resin composition molded article containing reinforcing fibers (A), a polyamide resin composition (B), and an ammonium salt (C) composed of an aliphatic dicarboxylic acid having 6 to 12 carbon atoms and ammonia, wherein the amount of the reinforcing fibers (A), the polyamide resin composition (B), and the ammonium salt (C) composed of an aliphatic dicarboxylic acid having 6 to 12 carbon atoms and ammonia is 5 to 50 parts by weight of the reinforcing fibers (A), 40 to 94.9 parts by weight of the polyamide resin composition (B), and the ammonium salt (C) composed of an aliphatic dicarboxylic acid having 6 to 12 carbon atoms and ammonia, relative to 100 parts by weight in total of the reinforcing fibers (A), the polyamide resin composition (B), and the ammonium salt (C) composed of an aliphatic dicarboxylic acid having 6 to 12 carbon atoms and ammonia. The fiber-reinforced polyamide resin composition molded article contains 0.1 to 10 parts by weight of an ammonium salt (C) made of ammonia, and the weight-average fiber length (Lwa1) of the reinforcing fibers (A) in the fiber-reinforced polyamide resin composition molded article is 0.4 mm or more and 7.0 mm or less. The polyamide resin composition (B) comprises a polyamide resin (B1), a resin (B2) having a reactive functional group, and a compound (B3) produced by the reaction of (B1) and (B2), and the resin (B2) having a reactive functional group is in a state of being dispersed in the form of particles with a number-average particle diameter of 10 to 1,000 nm.

[0020] First, the molded article made from the fiber-reinforced polyamide resin composition of the present invention will be described in detail. <Reinforced fiber (A)> The reinforcing fibers (A) in the present invention can improve the mechanical properties of the molded article by providing fiber reinforcement to the polyamide resin composition (B). Furthermore, if the reinforcing fibers (A) have inherent properties such as electrical conductivity or thermal conductivity, they can impart these properties to the molded article, which the polyamide resin composition (B) alone cannot achieve. Furthermore, for the purpose of imparting electrical conductivity, reinforcing fibers coated with metals such as nickel, copper, and ytterbium are also preferably used.

[0021] The reinforcing fibers are not particularly limited, and examples thereof include carbon fibers, organic fibers, glass fibers, and metal fibers. Of these, carbon fibers are more preferably used to improve mechanical properties. Examples of carbon fibers include PAN (polyacrylonitrile)-based carbon fibers, pitch-based carbon fibers, rayon-based carbon fibers, cellulose-based carbon fibers, vapor-grown carbon fibers, and graphitized fibers of these. To further improve impact properties, it is preferable to use them in combination with organic fibers, which will be described later.

[0022] The carbon fibers preferably have a surface oxygen concentration ratio [O / C], which is the ratio of the number of oxygen (O) to carbon (C) atoms on the fiber surface as measured by X-ray photoelectron spectroscopy, of 0.05 to 0.5. A surface oxygen concentration ratio of 0.05 or more ensures a sufficient number of functional groups on the carbon fiber surface, enabling stronger adhesion to the polyamide resin composition (B), thereby further improving the bending strength and tensile strength of the molded article. The surface oxygen concentration ratio is more preferably 0.1 or more. Furthermore, the upper limit of the surface oxygen concentration ratio is more preferably 0.3 or less, in order to balance the handleability and productivity of the carbon fiber.

[0023] The surface oxygen concentration ratio of carbon fiber is determined by X-ray photoelectron spectroscopy according to the following procedure. First, if a sizing agent or the like is attached to the surface of the carbon fiber, the sizing agent or the like is removed with a solvent. The carbon fiber is cut into 20 mm pieces and spread out on a copper sample support. After that, AlKα1, 2 is used as the X-ray source, and the sample chamber is heated to 1 × 10 -8 Torr. C is used as a correction value for peaks due to charging during measurement. 1s The kinetic energy (KE) of the main peak of C is adjusted to 1202 eV. 1s The peak area is determined by drawing a straight baseline in the KE range of 1191 to 1205 eV. 1s The peak area is determined by drawing a straight baseline in the range of 947 to 959 eV as KE.

[0024] Here, the surface oxygen concentration ratio [O / C] is the above O 1s Peak area and C 1sThe atomic ratio is calculated from the peak area ratio using a sensitivity correction value specific to the device. The X-ray photoelectron spectrometer used is an ES-200 model manufactured by Kokusai Electric Co., Ltd., with a sensitivity correction value of 1.74. The average fiber diameter of the carbon fibers is not particularly limited, but is preferably 1 to 20 μm, more preferably 3 to 15 μm, from the viewpoint of the mechanical properties and surface appearance of the molded product.

[0025] The carbon fibers may be surface-treated for the purpose of improving the adhesion between the carbon fibers and the polyamide resin composition (B), etc. Examples of surface treatment methods include electrolytic treatment, ozone treatment, and ultraviolet treatment.

[0026] The carbon fibers may be treated with a sizing agent for the purposes of preventing fuzzing of the carbon fibers, improving adhesion between the carbon fibers and the polyamide resin composition (B), etc. By applying a sizing agent, surface properties such as functional groups on the carbon fiber surface can be improved, and adhesion and mechanical properties (particularly impact strength) of the molded article can be improved.

[0027] Examples of sizing agents include epoxy resins, phenolic resins, polyethylene glycol, polyurethane, polyester, emulsifiers, and surfactants. Two or more of these may be used. The sizing agent is preferably water-soluble or water-dispersible. Epoxy resins with excellent wettability with carbon fibers are preferred, and polyfunctional epoxy resins are more preferred.

[0028] Examples of polyfunctional epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, aliphatic epoxy resins, and phenol novolac epoxy resins. Among these, aliphatic epoxy resins are preferred because they are more likely to exhibit adhesion to the polyamide resin composition (B). Because aliphatic epoxy resins have a flexible skeleton, they tend to form a highly tough structure even with a high crosslink density. Furthermore, when aliphatic epoxy resins are present between carbon fiber and a polyamide resin composition, they are flexible and less likely to peel, thereby further improving the strength of the molded product.

[0029] Examples of polyfunctional aliphatic epoxy resins include diglycidyl ether compounds and polyglycidyl ether compounds. Examples of diglycidyl ether compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ethers, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, polytetramethylene glycol diglycidyl ethers, and polyalkylene glycol diglycidyl ethers. Examples of polyglycidyl ether compounds include glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ethers, sorbitol polyglycidyl ethers, arabitol polyglycidyl ethers, trimethylolpropane polyglycidyl ethers, trimethylolpropane glycidyl ethers, pentaerythritol polyglycidyl ethers, and polyglycidyl ethers of aliphatic polyhydric alcohols.

[0030] Among the above aliphatic epoxy resins, trifunctional or higher aliphatic epoxy resins are preferred, and aliphatic polyglycidyl ether compounds having three or more highly reactive glycidyl groups are more preferred. Aliphatic polyglycidyl ether compounds have a good balance of flexibility, crosslink density, and compatibility with the polyamide resin composition (B), and can further improve adhesion. Among these, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ethers, polyethylene glycol glycidyl ethers, and polypropylene glycol glycidyl ethers are more preferred.

[0031] The amount of sizing agent attached is preferably 0.01 to 10% by weight, based on 100% by weight of the total of the sizing agent and carbon fiber. If the amount of sizing agent attached is 0.01% by weight or more, the adhesion to the polyamide resin composition (B) can be further improved. The amount of sizing agent attached is more preferably 0.05% by weight or more, and even more preferably 0.1% by weight or more. On the other hand, if the amount of sizing agent attached is 10% by weight or less, the physical properties of the polyamide resin composition (B) can be maintained at a higher level. The amount of sizing agent attached is more preferably 5% by weight or less, and even more preferably 2% by weight or less.

[0032] <Organic Fiber (A2)> In the fiber-reinforced polyamide resin composition molded article of the present invention, the reinforcing fiber (A) may contain the carbon fiber (A1) and the organic fiber (A2). The carbon fiber (A1) is rigid and brittle, and therefore does not easily tangle and breaks easily. On the other hand, the organic fiber (A2) is flexible, and therefore does not easily break during molding, and tends to remain in the molded article while maintaining its long fiber length. Therefore, by including the flexible and break-resistant organic fiber (A2), the impact properties of the molded article can be significantly improved.

[0033] Specifically, by setting the remaining fiber length of the organic fiber (A2) in the molded article (in other words, the weight average fiber length (Lwa2) in the molded article) to 3 mm or more and 7 mm or less, the molded article can be imparted with higher impact resistance.

[0034] The organic fiber (A2) can be appropriately selected within a range that does not significantly deteriorate the mechanical properties of the molded article. Examples include fibers obtained by spinning resins such as polyolefin resins (e.g., polyethylene and polypropylene); polyamide resins (e.g., nylon 6, nylon 66, and aromatic polyamide); polyester resins (e.g., polyethylene terephthalate and polybutylene terephthalate); fluororesins (e.g., polytetrafluoroethylene, perfluoroethylene-propene copolymer, and ethylene-tetrafluoroethylene copolymer); liquid crystal polymers (e.g., liquid crystal polyester and liquid crystal polyesteramide); and polyarylene sulfides (e.g., polyether ketone, polyether sulfone, and polyphenylene sulfide). Two or more of these may be used. It is preferable to appropriately select and use from among these organic fibers (A2). In particular, the melting temperature of the organic fiber (A2) is preferably 30°C to 150°C higher, and more preferably 50°C to 100°C higher, than the molding temperature (melting temperature) of the polyamide resin composition (B). Alternatively, organic fibers (A2) made of a resin incompatible with the polyamide resin composition (B) are preferred because they remain in a fibrous state within the molded article, thereby further improving the impact properties of the molded article. Examples of organic fibers (A2) with a high melting temperature include polyphenylene sulfide resin, fluororesin, and liquid crystal polyester fiber. It is preferred to use at least one type of fiber selected from the group consisting of these as the organic fibers (A2) in the present invention.

[0035] The single fiber fineness of the organic fiber (A2) is preferably 0.1 to 50 dtex, more preferably 3 dtex or more, and even more preferably 6 dtex or more. By setting the single fiber fineness within the above-mentioned range, the fiber is resistant to fiber shear during molding, and the fiber length tends to remain long in the molded article, which is preferable because it is possible to increase the impact strength of the molded article.

[0036] The fiber strength of the organic fiber (A2) can be determined by a known single fiber tensile test. Here, the fiber strength of the organic fiber (A2) can be calculated by conducting a tensile test in a room under standard conditions (20°C, 65% RH) under conditions of a grip distance of 250 mm and a pulling speed of 300 mm / min, and dividing the load at fiber break by the single fiber fineness. Here, the single fiber fineness represents the thickness of a thread that weighs 1 g per 10,000 m of length, and the single fiber fineness of the organic fiber (A2) used in the present invention can be determined by a known fiber fineness measurement method (for example, JIS L 1013:2010).

[0037] The fiber strength is preferably 4 cN / dtex or more. If it is less than 4 cN / dtex, the impact properties of the molded article will be particularly poor. It is more preferably more than 4 cN / dtex, even more preferably 5 cN / dtex or more, and even more preferably 6 cN / dtex or more. Furthermore, the initial fiber modulus can be calculated from the initial slope in a stress-strain curve obtained at the above-mentioned fiber strength.

[0038] The fiber strength is preferably 50 cN / dtex or less, more preferably 40 cN / dtex or less, and even more preferably 30 cN / dtex or less. If the fiber strength exceeds 50 cN / dtex, cutting of the fiber becomes difficult, which is undesirable as it reduces the productivity of the molding material.

[0039] The density of the organic fiber (A2) can be determined by known density measurement methods (for example, JIS L 1015:2010).

[0040] The content of organic fiber (A2) in the molded article of the present invention is preferably 1 to 50 parts by weight per 100 parts by weight of the total of carbon fiber (A1) and organic fiber (A2). If the content of organic fiber (A2) is less than 1 part by weight, the impact properties of the molded article will be reduced. The content of organic fiber (A2) is more preferably 5 parts by weight or more, even more preferably 10 parts by weight or more, and even more preferably 20 parts by weight or more. On the other hand, if the content of organic fiber (A2) exceeds 50 parts by weight, entanglement of the fibers will increase, the dispersibility of the organic fiber (A2) in the molded article will be reduced, and this will often result in a reduction in the impact properties of the molded article. The content of organic fiber (A2) is preferably 40 parts by weight or less, more preferably 30 parts by weight or less. When the reinforcing fibers (A) of the fiber-reinforced polyamide resin composition molded article of the present invention contain carbon fibers (A1) and organic fibers (A2), the content of carbon fibers (A1) is preferably 50 to 99 parts by weight per 100 parts by weight of the total of carbon fibers (A1) and organic fibers (A2). If the content of carbon fibers (A1) is less than 50 parts by weight, it is difficult to obtain high mechanical properties of the molded article.

[0041] <Weight average fiber length> In the fiber-reinforced polyamide resin composition molded article of the present invention, the weight-average fiber length (Lwa1) of the reinforcing fibers (A) in the molded article is 0.4 mm or more and 7.0 mm or less. If the weight-average fiber length (Lwa1) of the reinforcing fibers (A) is less than 0.4 mm, the effect of improving the bending strength and impact properties of the molded article is difficult to achieve. Lwa1 is more preferably 0.5 mm or more, and even more preferably 0.7 mm or more. On the other hand, if the weight-average fiber length (Lwa1) exceeds 7.0 mm, it becomes difficult to suppress entanglement between the single filaments of the reinforcing fibers (A), which causes fiber breakage, making it difficult to achieve the effect of improving the bending strength of the molded article. Lwa1 is more preferably 4 mm or less.

[0042] Furthermore, in the molded article of the present invention, when the reinforcing fiber (A) contains carbon fiber (A1) and organic fiber (A2), the weight-average fiber length (Lwa2) of the organic fiber (A2) in the molded article is preferably 3 mm or more and 7 mm or less. If the weight-average fiber length (Lwa2) of the organic fiber (A2) is less than 3 mm, the reinforcing effect of the organic fiber (A2) in the molded article is poor, resulting in poor impact properties. Lwa2 is more preferably 4 mm or more. On the other hand, if the weight-average fiber length (Lwa2) exceeds 7 mm, entanglement between the single filaments of the organic fiber (A2) is difficult to suppress, resulting in fiber breakage, resulting in poor impact properties of the molded article. Lwa2 is more preferably 6 mm or less. By setting the weight-average fiber length (Lwa2) of the organic fiber (A2) within the above range, entanglement between the single filaments of the organic fiber (A2) is suppressed, and the organic fiber (A2) exists in a curved state. As a result, cracks do not propagate in one direction when the molded product is broken, and more impact energy can be absorbed, improving the impact strength of the molded product.

[0043] Here, the "weight average fiber length" in the present invention refers to an average fiber length calculated from the following formula, which does not simply take a number average but takes into account the contribution of fiber length, by applying the calculation method for weight average molecular weight to the calculation of fiber length: The weight average fiber length of each of the carbon fiber (A1) and the organic fiber (A2) can be calculated from the following formula. Weight average fiber length = Σ(Mi 2 ×Ni) / Σ(Mi×Ni) Mi: Fiber length (mm) Ni: Number of reinforcing fibers with fiber length Mi.

[0044] The weight-average fiber length can be measured, for example, by a method in which a test piece of any size cut out from an ISO dumbbell test piece is sandwiched between cover glasses and heated on a hot stage set to a temperature (e.g., 200 to 300°C) at which the organic fiber (A2) does not melt and only the polyamide resin composition (B) melts, and the piece is formed into a film without applying excessive pressure to uniformly disperse the fibers, thereby obtaining a film in which the fibers are uniformly dispersed; or by a method in which a test piece of any size cut out from an ISO dumbbell test piece is placed in an organic solvent in which the organic fiber (A2) does not dissolve and only the polyamide resin composition (B) dissolves, and then heated to dissolve as necessary, and the organic solution is filtered to obtain an observation sample in which the fibers are uniformly dispersed. The sample obtained by the above method is observed under an optical microscope (50 to 200 magnifications), and the fiber lengths of 1,000 randomly selected carbon fibers (A1) and organic fibers (A2) are measured. The weight average fiber length (Lwa1) of the carbon fibers (A1) and the weight average fiber length (Lwa2) of the organic fibers (A2) are calculated using the above formula.

[0045] The weight-average fiber length of the carbon fiber (A1) and the organic fiber (A2) in the molded product can be adjusted by, for example, molding conditions. In the case of injection molding, examples of such molding conditions include pressure conditions such as back pressure and dwell pressure, time conditions such as injection time and dwell time, and temperature conditions such as cylinder temperature and mold temperature. Specifically, taking advantage of the fact that the organic fiber (A2) is more flexible and less likely to break than the carbon fiber (A1), the back pressure and other pressure conditions can be appropriately increased to appropriately increase the shear force in the cylinder, thereby shortening the average fiber length of the carbon fiber (A1) compared to that of the organic fiber (A2). Alternatively, the injection time can be appropriately shortened to appropriately increase the shear force during injection, thereby shortening the average fiber length of the carbon fiber (A1) compared to that of the organic fiber (A2). Furthermore, by appropriately lowering the cylinder temperature, mold temperature, and other temperatures, the viscosity of the flowing resin increases, thereby increasing the shear force. This method can also be used to shorten the average fiber length of the carbon fiber (A1) compared to that of the organic fiber (A2). In the present invention, the average fiber lengths of the carbon fibers (A1) and the organic fibers (A2) in the molded product can be adjusted to the desired range by appropriately changing the conditions as described above. Among these, it is particularly effective to adjust the shear force by controlling the back pressure conditions and injection time. However, care must be taken because if the shear force acting on the fibers is increased more than necessary, the average fiber lengths of not only the carbon fibers (A1) but also the organic fibers (A2) will be shortened.

[0046] <Polyamide resin composition (B)> The polyamide resin composition used in the present invention comprises a polyamide resin (B1), a resin (B2) having a reactive functional group, and a compound (B3) formed by the reaction of (B1) with (B2).

[0047] <Polyamide resin (B1)> The polyamide resin (B1) is a resin made of a polymer having an amide bond, and is made primarily from amino acids, lactams, or diamines and dicarboxylic acids. Typical examples of such raw materials include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and para-aminomethylbenzoic acid; lactams such as ε-caprolactam and ω-laurolactam; tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, metaxylenediamine, paraxylylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, and 1-amino-3-(2-aminomethyl)cyclohexane. aliphatic, alicyclic, or aromatic diamines such as aminomethyl-3,5,5-trimethylcyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, and aminoethylpiperazine; and aliphatic, alicyclic, or aromatic dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodiumsulfoisophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid. In the present invention, polyamide homopolymers or copolymers derived from these raw materials can be used alone or in the form of a mixture.

[0048] Specific examples of polyamides that are particularly useful in the present invention include polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polypentamethylene adipamide (nylon 56), polytetramethylene adipamide (nylon 46), polyhexamethylene sebacamide (nylon 610), polypentamethylene sebacamide (nylon 510), polyhexamethylene dodecamide (nylon 612), and polyundecaneamide (nylon 1 1), Polydodecanamide (Nylon 12), Polycaproamide / Polyhexamethylene adipamide copolymer (Nylon 6 / 66), Polycaproamide / Polyhexamethylene terephthalamide copolymer (Nylon 6 / 6T), Polyhexamethylene adipamide / Polyhexamethylene terephthalamide copolymer (Nylon 66 / 6T), Polyhexamethylene adipamide / Polyhexamethylene isophthalamide copolymer (Nylon 66 / 6I), Polyhe Polyhexamethylene adipamide / polyhexamethylene isophthalamide / polycaproamide copolymer (nylon 66 / 6I / 6), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 6T / 6I), polyhexamethylene terephthalamide / polydodecanamide copolymer (nylon 6T / 12), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide Examples include copolymer (nylon 66 / 6T / 6I), polyxylylene adipamide (nylon XD6), polyhexamethylene terephthalamide / poly-2-methylpentamethylene terephthalamide copolymer (nylon 6T / M5T), polyhexamethylene terephthalamide / polypentamethylene terephthalamide copolymer (nylon 6T / 5T), polynonamethylene terephthalamide (nylon 9T), and mixtures or copolymers thereof.

[0049] Particularly preferred examples include nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, nylon 6 / 66, nylon 66 / 6T, and nylon 6T / 6I copolymers. Furthermore, it is practically advantageous to use these polyamides as a mixture depending on the required properties, such as moldability, heat resistance, toughness, and surface properties. Of these, nylon 6, nylon 66, nylon 610, nylon 11, and nylon 12 are most preferred.

[0050] Furthermore, in the molded article of the present invention, the polyamide resin (B1) is preferably a mixture of a polyamide resin (B1a) containing polyamide 6 or polyamide 66 as a constituent component and one or more polyamide resins (B1b) selected from the group consisting of polyamide 610, polyamide 612, polyamide 11, polyamide 12, polyamide 1010, polyamide 1012, and polyamide 9T, and copolymer polyamides containing at least one of these as a constituent component. These polyamides are blended according to required properties, such as moldability, heat resistance, toughness, and surface properties. The polyamide resin (B1b) has a water absorption rate of 5% or less when left in an aqueous environment at 25°C for 300 hours. By appropriately adjusting the blending ratio of the polyamide resins (B1a) and (B1b), the water absorption rate of the molded article can be reduced to 3.0% or less when left in an environment of 80°C and 95% RH for 24 hours, thereby preventing a decrease in the rigidity of the molded article when it absorbs water. A water absorption rate of more than 3.0% is not preferred because the rigidity of the material decreases significantly when it absorbs water, and a water absorption rate of 2.7% or less is more preferred.

[0051] Furthermore, in the present invention, it has been revealed that fiber dispersion can be improved by selecting a polyamide resin (B1b) whose SP value lies between that of (B1a) and that of resin (B2) described later. The mechanism behind this is speculation, but it is believed that the polyamide resin (B1b) controls the SP values of the polyamide 6 resin (B1a) and the resin (B2) described later when mixed with the polyamide resin (B1b). In other words, it is speculated that the location of (B1b) between (B1a) and (B2), which have widely differing SP values, further improves compatibility with the carbon fiber (A1) and the organic fiber (A2).

[0052] Among these combinations, it is preferable to select polyamide 6 resin for (B1a) and polyamide 610 for (B1b) from the viewpoints of water absorption rate and fiber dispersibility.

[0053] Although there are no particular limitations on the degree of polymerization of these polyamides, the relative viscosity, measured at 25°C in a 98% concentrated sulfuric acid solution with a sample concentration of 0.01 g / ml, is preferably in the range of 1.5 to 7.0, and particularly preferably in the range of 1.8 to 5.0. A relative viscosity of 1.5 or higher imparts high impact resistance to the fiber-reinforced resin composition. Furthermore, a relative viscosity of 7.0 or lower provides excellent moldability.

[0054] <Resin having a reactive functional group (B2)> The base resin for the resin (B2) having a reactive functional group is not particularly limited, but may be at least one resin selected from, for example, polyamide, polyester, polyphenylene sulfide, polyphenylene oxide, polycarbonate, polylactic acid, polyacetal, polysulfone, tetrafluoroethylene, polyetherimide, polyamideimide, polyimide, polyethersulfone, polyetherketone, polythioetherketone, polyetheretherketone, polyethylene, polypropylene, styrene-based resins such as polystyrene and ABS, rubber polymers, polyalkylene oxides, etc., and is different from the polyamide resin (B1). Among these, as the base resin for the resin (B2), resins selected from polyolefin resins such as polyethylene resins and polypropylene resins, styrene-based resins, and rubber polymers are more preferred due to the ease of introducing reactive functional groups, and rubber polymers are even more preferred from the viewpoint of imparting impact absorption properties.

[0055] The rubbery polymer is a polymer containing a polymer with a low glass transition temperature, in which some of the intermolecular bonds are constrained by covalent bonds, ionic bonds, van der Waals forces, entanglement, etc. The glass transition temperature of the rubbery polymer is preferably 25°C or lower. A glass transition temperature exceeding 25°C is undesirable because it results in poor impact resistance.

[0056] Examples of rubbery polymers include diene rubbers such as polybutadiene, polyisoprene, random copolymers and block copolymers of styrene-butadiene, hydrogenated products of these block copolymers, acrylonitrile-butadiene copolymers, and butadiene-isoprene copolymers; random copolymers and block copolymers of ethylene-propylene, random copolymers and block copolymers of ethylene-butene, copolymers of ethylene and α-olefins; ethylene-unsaturated carboxylic acid copolymers such as ethylene-acrylic acid copolymers and ethylene-methacrylic acid copolymers; ethylene-unsaturated carboxylic acid ester copolymers such as ethylene-acrylic acid esters and ethylene-methacrylic acid esters; and copolymers in which a part of the unsaturated carboxylic acid is gold. Preferred examples of the polymerizable monomer include metal salts such as ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymers, such as ethylene-acrylic acid-metal acrylic acid salt and ethylene-methacrylic acid-metal methacrylic acid salt; acrylic acid ester-butadiene copolymers, for example, butyl acrylate-butadiene copolymers, and other acrylic elastic polymers; copolymers of ethylene and fatty acid vinyl, such as ethylene-vinyl acetate; ethylene-propylene-ethylidenenorbornene copolymers, ethylene-propylene-hexadiene copolymers, and other ethylene-propylene non-conjugated diene terpolymers; butylene-isoprene copolymers; chlorinated polyethylene; polyamide elastomers; and thermoplastic elastomers, such as polyester elastomers.

[0057] When used for the polyamide resin (B1), from the viewpoint of obtaining excellent impact strength, ethylene-unsaturated carboxylic acid ester copolymers, ethylene-propylene random copolymers and block copolymers, ethylene-butene random copolymers and block copolymers, and copolymers of ethylene and α-olefins are preferably used.

[0058] The unsaturated carboxylic acid ester in the ethylene-unsaturated carboxylic acid ester copolymer is preferably a (meth)acrylic acid ester. Specific examples of the unsaturated carboxylic acid ester include (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and stearyl (meth)acrylate. Here, "(meth)acrylic acid" means "acrylic acid or methacrylic acid." The weight ratio of the ethylene component to the unsaturated carboxylic acid ester component in the copolymer is not particularly limited, but is preferably in the range of 90 / 10 to 10 / 90, more preferably 85 / 15 to 15 / 85. The number-average molecular weight of the ethylene-unsaturated carboxylic acid ester copolymer is not particularly limited, but is preferably in the range of 1,000 to 70,000 from the viewpoint of fluidity and mechanical properties.

[0059] The reactive functional group contained in the resin (B2) having a reactive functional group is not particularly limited as long as it reacts with the functional group present in the polyamide resin (B1), but preferably includes at least one selected from an amino group, a carboxyl group, a metal salt of a carboxyl group, a hydroxyl group, an epoxy group, an acid anhydride group, an isocyanate group, a mercapto group, an oxazoline group, a sulfonic acid group, etc. Among these, groups selected from an amino group, a carboxyl group, a metal salt of a carboxyl group, an epoxy group, an acid anhydride group, and an oxazoline group are more preferably used because they have high reactivity and are less likely to undergo side reactions such as decomposition and crosslinking.

[0060] When an acid anhydride group is introduced into a rubbery polymer, the method can be carried out by a known technique and is not particularly limited. For example, a method of copolymerizing an acid anhydride such as maleic anhydride, itaconic anhydride, endic anhydride, citraconic anhydride, or 1-butene-3,4-dicarboxylic anhydride with a monomer that is a raw material for the rubbery polymer, or a method of grafting an acid anhydride onto a rubbery polymer can be used.

[0061] Furthermore, when an epoxy group is introduced into a rubbery polymer, the method can be carried out by a known technique and is not particularly limited. For example, a method of copolymerizing a vinyl monomer having an epoxy group, such as a glycidyl ester compound of an α,β-unsaturated acid such as glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, or glycidyl itaconate, with a monomer that is a raw material for the rubbery polymer, a method of polymerizing a rubbery polymer using a polymerization initiator or chain transfer agent having an epoxy group, or a method of grafting an epoxy compound onto a rubbery polymer can be used.

[0062] Furthermore, when an oxazoline group is introduced into a rubbery polymer, the method can be carried out by a known technique and is not particularly limited. For example, a method can be used in which a vinyl monomer having an oxazoline group, such as 2-isopropenyl-oxazoline, 2-vinyl-oxazoline, 2-acroyl-oxazoline, or 2-styryl-oxazoline, is copolymerized with a monomer that is a raw material for the rubbery polymer.

[0063] The number of functional groups per molecular chain in the resin (B2) having a reactive functional group is not particularly limited, but is usually preferably 1 to 10, and more preferably 1 to 5 to reduce side reactions such as crosslinking.

[0064] The polyamide resin composition (B) of the present invention comprises a polyamide resin (B1), a resin (B2) having a reactive functional group, and a compound (B3) formed by the reaction of (B1) with (B2). The polyamide resin composition (B) can be obtained by melt-kneading the polyamide resin (B1) and the resin (B2) having a reactive functional group. Furthermore, since (B2) has a reactive functional group, the reaction between (B1) and (B2) produces (B3) during the melt-kneading of (B1) and (B2). The polyamide resin composition (B) is obtained in which (B1) forms a matrix phase as a continuous phase and (B2) is dispersed in particulate form as a dispersed phase. The structure of the particles composed of (B2) is highly controlled, significantly contributing to improved impact resistance. The polyamide resin composition (B), in which polyamide resin (B1) and component (B) are mixed to form a matrix resin and resin (B2) is dispersed in the matrix resin in particulate form, contains particles of resin (B2). The number-average particle diameter of the particles must be 10 to 1,000 nm. If the particle diameter is less than 10 nm, the impact resistance characteristic of the present invention is not exhibited, while if it exceeds 1,000 nm, the rigidity characteristic of the present invention is reduced, which is undesirable. By achieving improved impact resistance with a small amount of particles of resin (B2) with a highly controlled structure, a fiber-reinforced polyamide resin composition molded article with an excellent balance between rigidity and impact resistance can be obtained.

[0065] Furthermore, the fiber-reinforced polyamide resin composition molded article of the present invention preferably contains, in particles of resin (B2), a compound (B3) formed by the reaction of polyamide resin (B1) and resin (B2) and having an average particle size of 1 to 100 nm. Furthermore, the area ratio of the compound (B3) formed by the reaction of components (B1) and (B2) in the particles of resin (B2) is preferably 20% or more. Even if the amount of resin (B2) forming the dispersed phase is small, by controlling the structure within the dispersed phase as described above, a fiber-reinforced polyamide resin composition molded article having an excellent balance between rigidity and impact resistance can be obtained.

[0066] Morphology observation can be performed using known techniques. For example, the center of a test specimen in the cross-sectional direction is cut into 1-2 mm squares, and the resin (B2) having reactive functional groups is stained with ruthenium tetroxide. Ultrathin sections with a thickness of 0.1 μm or less (approximately 80 nm) are then obtained using an ultramicrotome, and the resin portion of the section (excluding the reinforcing fibers) consisting of the polyamide resin (B1), resin (B2), and compound (B3) is observed using a transmission electron microscope. The number-average particle size (Xn) of the particles is determined by randomly selecting 400 or more particles from the obtained image, analyzing the particle size distribution using image analysis software "Scion Image" manufactured by Scion Corporation, and calculating it using the following formula: Number average particle diameter (Xn)=Σ(Xi×ni) / Σni Xi: particle diameter ni: Number of particles corresponding to particle diameter (Xi) (i=1, 2, 3, . . . , n)

[0067] The number average particle size of particles made of resin (B2) can be determined from an image magnified 10,000 times. The number average particle size of compound (B3) contained in particles made of (B2) and produced by the reaction of polyamide resins (B1) and (B2) can be determined from an image magnified 35,000 times.

[0068] The area ratio of compound (B3) in particles made of resin (B2) is calculated by analyzing the area of resin (B2) and the area of compound (B3) from an image magnified 35,000 times using a transmission electron microscope, using image analysis software "Scion Image" manufactured by Scion Corporation, and then using the following formula. Sn = Sp / (Sa2 + Sp) Sn: Area ratio (Sn) of compound (B3) in particles made of resin (B2) Sa2: Area occupied by resin (B2) Sp: Area occupied by compound (B3).

[0069] In the present invention, the method for producing the polyamide resin composition (B) is not particularly limited, but the following method, for example, is effective.

[0070] One method for producing the polyamide resin composition (B) is to feed the polyamide resin (B1) and the resin (B2) having a reactive functional group into a twin-screw extruder having a ratio L / D0 of the screw length L to the screw diameter D0 of 50 or more and having multiple full-flight zones and kneading zones, and melt-knead them under conditions that satisfy Pkmax≧Pfmin+0.3, where Pkmax (MPa) is the maximum resin pressure among the resin pressures in the kneading zones in the screw, and Pfmin (MPa) is the minimum resin pressure among the resin pressures in the full-flight zones in the screw.

[0071] From the viewpoint of improving kneading properties and reactivity, the L / D0 value is more preferably 60 to 200, and even more preferably 80 to 200. When using a twin-screw extruder with an L / D0 of less than 50, it is preferable to perform kneading multiple times to set the calculated L / D0 value of the resin composition passing through the extruder to 50 or more. L / D0 is the value obtained by dividing the screw length L by the screw diameter D0. Here, the screw length refers to the length from the upstream end of the screw segment located at the screw base (feed port) where the polyamide resin (B1) and the resin (B2) having a reactive functional group are supplied to the extruder, to the screw tip. The screws of twin-screw extruders are configured by combining screw segments with different lengths and shapes, such as full-flight and kneading disks. In an extruder, the side where raw materials are supplied is sometimes referred to as the upstream side, and the side where the molten resin is discharged is sometimes referred to as the downstream side.

[0072] When the polyamide resin composition (B) is produced using a twin-screw extruder having an L / D0 of 50 or more, the screws of the twin-screw extruder preferably have multiple full-flight zones and kneading zones in order to improve kneading properties and reactivity. The full-flight zone is composed of one or more full flights, and the kneading zone is composed of one or more kneading discs.

[0073] If the maximum resin pressure in the kneading zone among the resin pressures indicated by resin pressure gauges installed at multiple locations in the kneading zone is Pkmax (MPa), and the minimum resin pressure in the full flight zone among the resin pressures indicated by resin pressure gauges installed at multiple locations in the full flight zone is Pfmin (MPa), it is preferable to manufacture under conditions where the Pkmax value is (Pfmin + 0.3) or more, and it is even more preferable to manufacture under conditions where the Pkmax value is (Pfmin + 0.5) or more.

[0074] A kneading zone consisting of one or more kneading discs has better kneading and reactivity of molten resin than a full-flight zone consisting of one or more full-flight discs. Filling the kneading zone with molten resin dramatically improves kneading and reactivity. The resin pressure is one indicator of the state of molten resin filling, and the higher the resin pressure, the more molten resin is filled. In other words, when using a twin-screw extruder, it is possible to effectively promote the reaction by increasing the resin pressure in the kneading zone to a certain extent compared to the resin pressure in the full-flight zone.

[0075] There are no particular limitations on the method for increasing the resin pressure in the kneading zone, but preferred methods include introducing a reverse screw zone, which has the effect of pushing the molten resin back upstream, or a seal ring zone, which has the effect of collecting the molten resin, between kneading zones or downstream of the kneading zones. The reverse screw zone or seal ring zone consists of one or more reverse screws or one or more seal rings, and these can also be combined.

[0076] For example, when a reverse screw zone is introduced between kneading zones or downstream of a kneading zone, it is preferable that the reverse screw zone has a length Lr / D0 = 0.1 to 10, where Lr is the length of the reverse screw zone, from the viewpoint of kneading ability and reactivity. The length Lr / D0 of the reverse screw zone is more preferably 0.2 to 8, and even more preferably 0.3 to 6. When multiple reverse screw zones are provided, it is preferable that all of the reverse screw zones satisfy the above Lr / D0 range. The length Lr of the reverse screw zone is defined as the distance between a perpendicular line from the upstream end of the most upstream reverse screw constituting the reverse screw zone to the center line of the screw axis and a perpendicular line from the downstream end of the most downstream reverse screw constituting the reverse screw zone to the center line of the screw axis.

[0077] When the polyamide resin composition (B) is produced using a twin-screw extruder having an L / D0 of 50 or more, the extrusion rate is preferably 0.01 kg / h or more per 1 rpm of the screw, more preferably 0.05 kg / h to 1 kg / h, even more preferably 0.08 to 0.5 kg / h, and most preferably 0.1 to 0.3 kg / h. Here, the extrusion rate refers to the weight (kg) of the molten mixture discharged from the extruder per hour.

[0078] The preferable range of values relating to the extrusion rate in the twin-screw extruder is based on the extrusion rate of a twin-screw extruder with a screw diameter of 41 mm. When the screw diameter is significantly different, for example, when a twin-screw extruder with a diameter of less than 30 mm or more than 50 mm is used, the extrusion rate can be interpreted as decreasing or increasing, preferably according to the 2.5th power law or the 3rd power law, more preferably according to the 2.5th power law, with respect to the screw diameter ratio before and after scale-down or scale-up.

[0079] For example, when a twin-screw extruder with a screw diameter of 20 mm is used, assuming that the extrusion rate follows the 2.5th power law of the screw diameter ratio before and after scale-down, the extrusion rate of the molten mixture per rpm of screw rotation is preferably 0.0017 kg / h or more, more preferably 0.0083 to 0.17 kg / h, even more preferably 0.013 to 0.083 kg / h, and most preferably 0.017 to 0.050 kg / h.

[0080] Furthermore, when a twin-screw extruder with a screw diameter of 100 mm is used, assuming that the extrusion rate follows the 2.5th power law of the screw diameter ratio before and after scale-up, the extrusion rate of the molten mixture per 1 rpm of the screw is preferably 0.093 kg / h or more, more preferably 0.46 to 9.29 kg / h, even more preferably 0.74 to 4.65 kg / h, and most preferably 0.93 to 2.79 kg / h.

[0081] The screw rotation speed is not particularly limited, but is preferably 10 rpm or higher, more preferably 15 rpm or higher, and even more preferably 20 rpm or higher.

[0082] The residence time in the twin-screw extruder is preferably 1 to 30 minutes, and more preferably 1.5 to 25 minutes. This residence time is a value representing the average residence time from when raw materials are supplied to the twin-screw extruder until they are discharged. The residence time is measured in a steady melt-kneaded state in which an uncolored melt-kneaded product is adjusted to a predetermined extrusion rate, and is measured by adding about 1 g of a colorant together with the raw materials from the base of the screw where the raw materials are supplied, from the time when the colorant is added until the extrusion from the extruder outlet reaches the maximum degree of coloration of the extrudate due to the colorant.

[0083] When the polyamide resin composition (B) is produced using a twin-screw extruder having an L / D0 of 50 or more, the screws of the twin-screw extruder are not particularly limited, and screws of a fully intermeshing type, a partially intermeshing type, a non-intermeshing type, or the like can be used. From the viewpoint of kneading property and reactivity, fully intermeshing type screws are preferred. Furthermore, the rotation direction of the screws may be either co-directional or counter-directional, but from the viewpoint of kneading property and reactivity, co-directional rotation is preferred. As the screws, co-rotating fully intermeshing type screws are most preferred.

[0084] The twin-screw extruder is preferably configured with a full-flight and / or kneading disc combination, with a screw configuration that effectively applies a shear field to the molten resin composition. Therefore, as described above, the twin-screw extruder preferably has multiple kneading zones, each consisting of one or more kneading discs, along its length. The total length of these kneading zones is preferably 5 to 50%, more preferably 10 to 40%, and even more preferably 15 to 30% of the total length of the screw.

[0085] If the length of each kneading zone in the screw of a twin-screw extruder is Lk, it is preferable from the viewpoint of kneading ability and reactivity that all kneading zones have a length of Lk / D0 = 0.2 to 10. The length Lk / D0 of each kneading zone is more preferably 0.3 to 9, and even more preferably 0.5 to 8. The length Lk of a kneading zone is defined as the distance between a perpendicular line from the upstream end of the most upstream kneading disc constituting the kneading zone to the center line of the screw shaft and a perpendicular line from the downstream end of the most downstream kneading disc constituting the kneading zone to the center line of the screw shaft. It is also preferable that the kneading zones of a twin-screw extruder are arranged throughout the entire screw, without being unevenly distributed at a specific position.

[0086] To remove reaction by-products or thermal degradation products, a vent vacuum zone is preferably provided and melt-kneaded at a reduced pressure of −0.07 MPa or less, more preferably −0.08 MPa or less. Here, the term “gauge pressure” refers to the pressure when atmospheric pressure is zero. The lower the gauge pressure, the higher the degree of vacuum and the greater the ability to remove volatile components. A vent vacuum zone with a gauge pressure of more than −0.07 MPa, i.e., a low degree of vacuum, is undesirable because it is not possible to sufficiently remove the volatile components, leaving impurities in the polyamide resin composition (B). By sufficiently removing the volatile components in the vent vacuum zone, it is possible to reduce the amount of impurities in the melt-kneaded product. There is no particular limitation on the number of vent vacuum zones, and it is preferable to install one or more. There is also no particular limitation on the location of the vent vacuum zone. However, installing at least one vent vacuum zone at a position where L / D0 = 0 to 10 is preferable because it enables effective removal of the volatile components.

[0087] The maximum resin temperature is preferably controlled to 180°C to 330°C during melt-kneading, and more preferably 200°C to 325°C. The maximum resin temperature here refers to the highest temperature measured using resin thermometers evenly installed at multiple positions in the extruder. If the maximum resin temperature is less than 180°C, the reactivity between polymers is low, and if it exceeds 330°C, thermal decomposition of the polymer progresses.

[0088] When using a twin-screw extruder, inert gas is introduced into the raw material inlet to suppress thermal degradation. The inert gas is preferably nitrogen gas.

[0089] The second method for producing the polyamide resin composition (B) is to melt-knead the polyamide resin (B1) and the resin (B2) having a reactive functional group under extensional flow. Extensional flow kneading has higher dispersion efficiency than the shear flow commonly used in melt-kneading, and therefore the reaction proceeds efficiently, especially in the case of alloying involving a reaction such as reactive processing.

[0090] When producing the polyamide resin composition (B) by melt-kneading under extensional flow, melt-kneading using an extruder is preferably used, and examples of extruders include single-screw extruders, twin-screw extruders, and multi-screw extruders with three or more screws. Among these, single-screw extruders and twin-screw extruders are preferably used, and twin-screw extruders are particularly preferred. The screws of such twin-screw extruders are not particularly limited, and screws of fully intermeshing type, partially intermeshing type, non-intermeshing type, etc. can be used. From the viewpoints of kneading property and reactivity, fully intermeshing type is preferred. Furthermore, the rotation direction of the screws may be either co-directional or counter-directional, but from the viewpoints of kneading property and reactivity, co-rotating is preferred. The most preferred screws are co-rotating fully intermeshing type.

[0091] In order to provide an extensional flow field suitable for reactive processing, the ratio of the total length of the extensional flow zones to the total length of the extruder screw is preferably in the range of 5 to 60%, more preferably 10 to 55%, and even more preferably 15 to 50%.

[0092] If the length of the extensional flow zone in the screw of the extruder is Lk and the screw diameter is D0, then from the viewpoint of kneading ability and reactivity, Lk / D0=0.2 to 10 is preferred, 0.3 to 9 is more preferred, and 0.5 to 8 is even more preferred. When multiple extensional flow zones are provided, it is preferred that all of the respective extensional flow zones satisfy the above Lk / D0 range. Furthermore, in the present invention, it is preferred that the extensional flow zones are disposed throughout the entire screw, without being concentrated at a specific position within the screw.

[0093] Preferred examples of the screw configuration of the extensional flow zone include a twist kneading disc consisting of a kneading disc, in which the helical angle θ, which is the angle between the apex on the disc tip side and the apex on the rear side of the kneading disc, is within the range of 0°<θ<90° in the half-rotation direction of the screw; a flight screw in which a resin passage is formed in the flight portion of the flight screw, the cross-sectional area of which decreases from the screw tip side to the rear end side; and a resin passage in the extruder in which the cross-sectional area through which the molten resin passes gradually decreases.

[0094] The extrusion rate per 1 rpm of the screw is preferably 0.01 kg / h or more. The extrusion rate refers to the weight (kg) of the molten mixture extruded per hour from the extruder. If the extrusion rate per 1 rpm of the screw is less than 0.01 kg / h, the extrusion rate relative to the rotation speed is insufficient, resulting in an excessively long residence time in the extruder, which can cause thermal degradation and a very low filling rate of the resin in the extruder, resulting in insufficient kneading. The screw rotation speed is not particularly limited, but is preferably 10 rpm or more, more preferably 50 rpm or more, and even more preferably 80 rpm or more. The extrusion rate is preferably 0.1 kg / h or more, more preferably 0.15 kg / h or more, and even more preferably 0.2 kg / h or more.

[0095] The residence time in the extruder is preferably 1 to 30 minutes, more preferably 1.5 to 28 minutes, and even more preferably 2 to 25 minutes. The residence time is a value representing the average residence time from when raw materials are fed into the extruder until they are discharged. The residence time is measured in a steady melt-kneaded state where an uncolored resin composition is adjusted to a predetermined extrusion rate. The residence time is measured from the time when approximately 1 g of colorant is added together with the raw materials at the base of the screw where the raw materials are fed, until the extrusion from the extruder outlet reaches the point where the coloring degree of the colorant in the extrudate reaches its maximum. A residence time of less than 1 minute is undesirable because the reaction time in the extruder is too short and the reaction is not sufficiently promoted. A residence time of more than 30 minutes is undesirable because the long residence time causes thermal degradation of the resin.

[0096] In both cases where the polyamide resin composition (B) is produced using a twin-screw extruder with an L / D0 of 50 or more, and where the polyamide resin composition (B) is produced by melt-kneading under extensional flow, it is preferable for the blending ratio of the polyamide resin (B1) and the resin (B2) having a reactive functional group to be 80 to 60% by weight of the polyamide resin (B1) and 20 to 40% by weight of the resin (B2). This is because the polyamide resin (B1) forms a continuous phase and the resin (B2) forms a dispersed phase, and particles made of the resin (B2) contain the compound (B3) of 1 to 100 nm produced by the reaction of (B1) and (B2), and the area ratio occupied by the compound (B3) is likely to be 20% or more.

[0097] <Ammonium salt (C)> The polyamide resin composition of the present invention contains an ammonium salt (ammonium salt (C)) composed of an aliphatic dicarboxylic acid having 6 to 12 carbon atoms and ammonia. To be clear, the ammonium salt (C) is (R(COO - )2·(NH 4+)2) (wherein R is a divalent aliphatic group having 4 to 10 carbon atoms), and primary ammonium salts, secondary ammonium salts, tertiary ammonium salts, and quaternary ammonium salts in which the hydrogen atoms of the ammonium ion are substituted with one or more functional groups other than hydrogen atoms do not fall under the category of ammonium salt (C) in the present invention.

[0098] When an aliphatic dicarboxylic acid having 6 to 12 carbon atoms is used instead of the ammonium salt (C), such an aliphatic dicarboxylic acid is sometimes used as a raw material for the polyamide resin composition (B), and it is presumed that it has a relatively high affinity with the polyamide resin (B1) contained in the polyamide resin composition (B). Furthermore, since the amino groups of the polyamide resin (B1) contained in the polyamide resin composition (B) can react with the carboxyl groups of the aliphatic dicarboxylic acid, it disperses to some extent in the polyamide resin (B1) contained in the polyamide resin composition (B). However, because the aliphatic dicarboxylic acid is an acid, increasing its content decomposes the polyamide resin (B1) contained in the polyamide resin composition (B), resulting in a deterioration in the mechanical properties of the resulting molded article.

[0099] On the other hand, ammonium salts of aliphatic dicarboxylic acids having 5 or less carbon atoms have a relatively high affinity with the polyamide resin (B1) contained in the polyamide resin composition (B), and are therefore presumed to disperse in the polyamide resin (B1) contained in the polyamide resin composition (B). However, ammonium salts of aliphatic dicarboxylic acids having 5 or less carbon atoms have a low molecular weight, and the ammonium salts are decomposed during the production of the polyamide resin (B1) contained in the polyamide resin composition (B), resulting in a deterioration in the mechanical properties of the resulting molded article.

[0100] The use of the ammonium salt (C) comprising an aliphatic dicarboxylic acid having 6 to 12 carbon atoms and ammonia proposed by the present invention provides the following actions and effects.

[0101] That is, since the ammonium salt (C) is thought to coordinate with the amide group or carboxyl terminal group of the polyamide resin (B1) contained in the polyamide resin composition (B), the ammonium salt (C) has excellent compatibility with the polyamide resin (B1) contained in the polyamide resin composition (B) and can be finely dispersed in the polyamide resin composition, improving the flowability of the polyamide resin composition (B). Furthermore, the ammonium salt (C), which improves flowability, exhibits good affinity for the polyamide resin (B1) contained in the polyamide resin composition (B). This does not inhibit the fiber dispersion of the reinforcing fibers (A) in a fiber-reinforced polyamide resin molded article. This allows the reinforcing fibers (A) to be dispersed as single fibers within the molded article, improving the fiber dispersion of the molded article. Furthermore, the high affinity of the ammonium salt (C) for the polyamide resin (B1) also contributes to the prevention of bleed-out to the surface of the molded article.

[0102] Furthermore, since the ammonium salt (C) has a higher molecular weight than ammonium salts formed from ammonia and an aliphatic dicarboxylic acid having 5 or less carbon atoms, decomposition and volatilization of the ammonium salt (C) are suppressed. Furthermore, since the ammonium salt (C) is neutral, even if a large amount is contained, decomposition of the polyamide resin by an acid or base during the production of the polyamide composition is suppressed. Therefore, the flowability of the polyamide resin composition (B) can be more effectively improved, and the mechanical properties and appearance quality of the resulting molded article can be improved.

[0103] Specific examples of the ammonium salt (C) include diammonium adipate, diammonium pimelate, diammonium suberate, diammonium azelaate, diammonium sebacate, and ammonium dodecanedioate. Two or more of these may be used as needed. Among these, diammonium adipate and diammonium sebacate are preferred from the viewpoints of raw material availability, balance of performance, and cost.

[0104] In the fiber-reinforced polyamide resin composition molded article of the present invention, the content of the ammonium salt (C) is 0.1 to 10 parts by weight per 100 parts by weight of the total of the reinforcing fibers (A), the polyamide resin composition (B), and the ammonium salt (C). If the content of the ammonium salt (C) is less than 0.1 part by weight, the flowability, fiber dispersion, and mechanical properties of the fiber-reinforced polyamide resin composition (B) will be reduced. The content of the ammonium salt (C) is preferably 0.2 parts by weight or more, more preferably 0.3 parts by weight or more, per 100 parts by weight of the total of the reinforcing fibers (A), the polyamide resin composition (B), and the ammonium salt (C). On the other hand, if the content of the ammonium salt (C) exceeds 10 parts by mass, plasticization of the polyamide resin (B1) will be accelerated, resulting in reduced mechanical properties of the resulting molded article. The content of the ammonium salt (C) is preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and even more preferably 1.5 parts by weight, per 100 parts by weight of the total of the reinforcing fiber (A), the polyamide resin composition (B), and the ammonium salt (C).

[0105] The content of the ammonium salt (C) and the content of the ammonium ion [B] in the resin composition can be determined by the following method.

[0106] If the polyamide resin composition contains incompatible components such as inorganic or organic particles, these components are separated either directly or after conversion to other forms such as oxides, and the amount of each component per unit weight of the polyamide resin composition is determined. The separation method can be appropriately selected depending on the components contained, and is not particularly limited. On the other hand, if the polyamide resin composition contains other compatible organic or inorganic components, components that can be separated by extraction with water or an organic solvent are separated by extraction, and the amount of each component per unit weight of the polyamide resin composition is determined. If this is difficult, the amount of each component per unit weight of the polyamide resin composition is determined by determining its content in the composition using analytical methods such as spectroscopic methods. When a compatible organic or inorganic component is contained, the amount of polyamide resin (B1) contained per unit weight of the polyamide resin composition can be determined using this method.

[0107] On the other hand, since the ammonium salt (C) can be extracted with water, a polyamide resin composition of known weight can be extracted for a sufficient period of time using, for example, a Soxhlet extractor, and the extracted solution can be analyzed using, depending on the components contained therein, methods such as NMR, FT-IR, GC-MS, and liquid chromatography, either alone or in combination, to identify the chemical structure of the ammonium salt (C) and determine the content of the ammonium salt (C) and the content of the ammonium ion [B].

[0108] <Content of each ingredient> The molded article of the present invention contains 5 to 50 parts by weight of reinforcing fiber (A) per 100 parts by weight of the total of reinforcing fiber (A), polyamide resin composition (B), and ammonium salt (C). If the content of reinforcing fiber (A) is less than 5 parts by weight, the mechanical properties of the molded article, particularly bending properties and impact properties, will be reduced. The content of reinforcing fiber (A) is preferably 7 parts by weight or more, more preferably 10 parts by weight or more. On the other hand, if the content of reinforcing fiber (A) exceeds 50 parts by weight, entanglement of the fibers will increase. As a result, fiber breakage will occur, resulting in a shortened fiber length and reduced bending properties and impact properties. The content of reinforcing fiber (A) is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, and even more preferably 15 parts by weight or less.

[0109] The content of polyamide resin composition (B) in the molded article of the present invention is 40 to 94.9 parts by weight per 100 parts by weight of the total of reinforcing fiber (A), polyamide resin composition (B), and ammonium salt (C). If the content of polyamide resin composition (B) is less than 40 parts by weight, the reinforcing fibers (A) will become more entangled with each other, resulting in fiber breakage, shortening the fiber length and reducing bending strength and impact properties. The content of polyamide resin composition (B) is preferably 50 parts by weight or more. On the other hand, if the content of polyamide resin composition (B) exceeds 94.9 parts by weight, the content of carbon fiber (A) and ammonium salt (C) will be relatively low, reducing the reinforcing effect of the fibers and reducing mechanical properties, particularly bending properties and impact properties. The content of polyamide resin composition (B) is preferably 85 parts by weight or less, more preferably 80 parts by weight or less.

[0110] <Other ingredients (D)> The molded article of the present invention may contain another component (D) in addition to the components (A) to (C) described above, provided that the object of the present invention is not impaired. Examples of the other component (D) include thermosetting resins, petroleum resins, flame retardants, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration dampers, antibacterial agents, insect repellents, deodorizing agents, color inhibitors, heat stabilizers, mold release agents, antistatic agents, plasticizers, lubricants, foaming agents, foam control agents, and coupling agents.

[0111] Here, the other component (D) may contain an epoxy resin, a phenolic resin, a terpene resin, or two or more of these to ensure higher fiber dispersion. Component (D) preferably has a high affinity with the polyamide resin composition (B). By selecting a component (D) with a high affinity with the polyamide resin composition (B), the component (D) is efficiently miscible with the polyamide resin composition (B) during injection molding, thereby further improving the dispersibility of the carbon fiber (A1) and the organic fiber (A2).

[0112] Component (D) is appropriately selected depending on the combination with the molding temperature of polyamide resin composition (B). For example, if the molding temperature is in the range of 150 to 270°C, a terpene resin is preferably used. If the molding temperature is in the range of 270 to 320°C, a phenol resin is preferably used.

[0113] The component (D) preferably has a heat loss of 10% by weight or less when heated at a rate of 10°C / min (in air) at the molding temperature. It is more preferably 5% by weight or less, and even more preferably 3% by weight or less. When the heat loss is 10% by weight or less, the generation of decomposition gases can be suppressed during injection molding with the polyamide resin composition (B), and the generation of voids during molding can be suppressed. Furthermore, gas generation can be suppressed, particularly during molding at high temperatures.

[0114] The term "heat loss" in the present invention refers to the weight loss rate of component (D) before and after heating under the above heating conditions, with the weight of component (D) before heating being taken as 100%, and can be calculated using the following formula: The weights before and after heating can be determined by measuring the weight at the molding temperature by thermogravimetric analysis (TGA) using a platinum sample pan in an air atmosphere at a heating rate of 10°C / min. Heating loss [weight%] = {(weight before heating - weight after heating) / weight before heating} x 100

[0115] Examples of terpene resins include polymers or copolymers obtained by polymerizing a terpene monomer, optionally with an aromatic monomer, in an organic solvent in the presence of a Friedel-Crafts catalyst. In particular, α-pinene, β-pinene, dipentene, and d-limonene are preferred terpene monomers due to their excellent compatibility with the polyamide resin composition (B). Homopolymers of these terpene monomers are even more preferred. Alternatively, hydrogenated terpene resins obtained by hydrogenating these terpene resins or terpene phenol resins obtained by reacting a terpene monomer with a phenol in the presence of a catalyst can also be used. Phenols preferably have one to three substituents on the benzene ring of the phenol, at least one of which is selected from the group consisting of alkyl groups, halogen atoms, and hydroxyl groups. Among these, phenol and cresol are preferred. Among these, hydrogenated terpene resins are preferred due to their excellent compatibility with the polyamide resin composition (B).

[0116] The glass transition temperature of the terpene resin is not particularly limited, but is preferably 30 to 100° C. A glass transition temperature of 30° C. or higher provides excellent handleability of component (D) during molding. A glass transition temperature of 100° C. or lower appropriately suppresses the fluidity of component (D) during molding, improving moldability.

[0117] The content of component (D) in the molding material of the present invention is preferably 1 to 20 parts by weight per 100 parts by weight of the total of the reinforcing fiber (A), polyamide resin composition (B), and ammonium salt. If the content of component (D) is less than 1 part by weight, the dispersibility of the carbon fiber (A1) and the organic fiber (A2) during injection molding decreases. The content of component (D) is preferably 2 parts by weight or more, and more preferably 4 parts by weight or more. On the other hand, if the content of component (D) exceeds 20 parts by weight, the bending properties and impact properties of the molded article decrease. The content is preferably 15 parts by weight or less, more preferably 12 parts by weight or less, and even more preferably 10 parts by weight or less.

[0118] The molding material of the present invention is not particularly limited, but specific examples of its shape include columns having cross sections as shown in FIGS. 1 to 4. In such columns, the carbon fibers (A1) and organic fibers (A2) are preferably aligned substantially parallel to the axial direction of the columns, and the lengths of the carbon fibers (A1) and organic fibers (A2) are preferably substantially the same as the length of the molding material. By ensuring that the fiber lengths are substantially the same as the molding material, the fiber lengths of the carbon fibers (A1) and organic fibers (A2) in molded articles produced using the same are easily controlled and can be made relatively long, resulting in molded articles with superior mechanical properties. The phrase "aligned substantially parallel" refers to a state in which the long axis of the fiber bundle containing the carbon fibers (A1) and organic fibers (A2) and the long axis of the molding material are oriented in the same direction, with the angular deviation between the axes being preferably 20° or less, more preferably 10° or less, and even more preferably 5° or less. The length of the molding material refers to the length in the fiber bundle orientation direction in the molding material, and in the case of the columnar bodies described above, it refers to the length in the longitudinal direction of the columnar bodies. Furthermore, "substantially the same length" means that the fiber bundles are not intentionally cut within the molding material, and that fiber bundles significantly shorter than the entire length of the molding material are not substantially included. While there are no particular limitations on the amount of fiber bundles shorter than the entire length of the molding material, the content of fiber bundles with lengths of 50% or less of the entire length of the molding material is preferably 30% by mass or less, and more preferably 20% by mass or less, of the total fiber bundles. More preferably, the content of fiber bundles with lengths of 85% or more of the entire length of the molding material is preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0119] It is preferable that the molding material has a substantially identical cross-sectional shape continuously over a certain length in the longitudinal direction. The longitudinal length of the molding material is in the range of 3 mm to 7 mm. If it is less than 3 mm, the reinforcing effect of the fibers is poor. In other words, if molding is performed using a molding material of less than 3 mm, the weight-average fiber length of the organic fibers in the resulting molded product cannot be made sufficiently long, resulting in poor impact properties. The molding material is preferably 4 mm or more, more preferably 5 mm or more. On the other hand, if the molding material exceeds 7 mm, moldability during injection molding decreases. In other words, if the length of the molding material exceeds 7 mm, it is not preferable because the molding material is too long and does not get caught in the injection molding machine.

[0120] The molding material of the present invention preferably has a fiber bundle containing continuous fiber bundles of carbon fibers (A1) and organic fibers (A2) within a resin composition comprising a polyamide resin composition (B) and an ammonium salt (C). In other words, the molding material preferably has a configuration in which the polyamide resin composition (B) and the ammonium salt (C) are disposed on the outside of the fiber bundle. The polyamide resin composition (B) may contain component (D), or a composite fiber bundle (E) may be formed in which component (D) is filled between each single fiber of the fiber bundle, with the polyamide resin composition (B) and the ammonium salt (C) disposed on the outside. The composite fiber bundle (E) is formed by impregnating a fiber bundle with component (D), and the carbon fibers (A1) and organic fibers (A2) are dispersed like islands in a sea of component (D).

[0121] The molding material of the present invention preferably has a core-sheath structure in which the fiber bundle or composite fiber bundle (E) is coated with the polyamide resin composition (B) and the ammonium salt (C). The polyamide resin composition (B) and the ammonium salt (C) that form the sheath structure may further contain other components as necessary to form a polyamide resin composition. Here, the term "coated structure" refers to a structure in which a composition containing the polyamide resin composition (B) and the ammonium salt (C) (hereinafter, the composition may also be simply referred to as "polyamide resin composition (B)") is disposed on and adhered to the surface of the fiber bundle or composite fiber bundle (E).

[0122] The component (D) contained in the molding material of the present invention is often low in molecular weight and is usually a relatively brittle and easily crushed solid or liquid at room temperature. By including a polyamide resin composition (B) on the outside of the composite fiber bundle (E), the high-molecular-weight polyamide resin composition (B) protects the composite fiber bundle (E), suppressing crushing and scattering of component (D) due to impacts and abrasions during transportation and handling of the molding material, and maintaining the shape of the molding material. From the viewpoint of handleability, it is preferable that the molding material of the present invention maintains the above-mentioned shape until it is used for molding.

[0123] The composite fiber bundle (E), the polyamide resin composition (B), and the ammonium salt (C) may be in a state where the polyamide resin composition (B) and the ammonium salt (C) partially penetrate into a part of the composite fiber bundle (E) near the boundary and are compatible with each other, or the composite fiber bundle (E) may be in a state where the polyamide resin composition (B) and the ammonium salt (C) are impregnated with each other.

[0124] In the molding material of the present invention, the carbon fibers (A1) and the organic fibers (A2) are preferably unevenly distributed in the fiber bundle cross section. Here, the fiber bundle cross section refers to a cross section perpendicular to the longitudinal direction of the fiber bundle. The uneven distribution of the carbon fibers (A1) and the organic fibers (A2) in the fiber bundle cross section suppresses entanglement of the carbon fibers (A1) and the organic fibers (A2) during molding, and a molded article in which the carbon fibers (A1) and the organic fibers (A2) are uniformly dispersed can be obtained. This makes it possible to further improve the impact properties of the molded article. Here, in the present invention, "uneven distribution" means that the carbon fibers (A1) and the organic fibers (A2) are not evenly distributed throughout the entire fiber bundle cross section, but are unevenly distributed in some areas.

[0125] For example, in the cross section of a fiber bundle in a polyamide resin composition (B) and an ammonium salt (C) 3, examples of the "uneven distribution" in the present invention include a so-called core-sheath structure, such as a structure in which carbon fiber (A1) 1 encapsulates organic fiber (A2) 2, as shown in FIG. 1, or a structure in which organic fiber (A2) 2 encapsulates carbon fiber (A1) 1, as shown in FIG. 2, or a structure in which bundles of carbon fiber (A1) 1 and bundles of organic fiber (A2) 2 are separated by a boundary, as shown in FIG. 3. In the present invention, "encapsulation" refers to a structure in which carbon fiber (A1) is disposed in the core and organic fiber (A2) is disposed in the sheath, or a structure in which organic fiber (A2) is disposed in the core and carbon fiber (A1) is disposed in the sheath. In the embodiment shown in FIG. 3, at least a portion of each of the carbon fiber (A1) and organic fiber (A2) is in contact with the polyamide resin composition (B) and ammonium salt (C) 3 in the outer layer in the cross section of the fiber bundle. In this case, the embodiment in which the carbon fiber (A1) or the organic fiber (A2) is in contact with the polyamide resin composition (B) and the ammonium salt (C) 3 also includes an embodiment in which the carbon fiber (A1) or the organic fiber (A2) is in contact with the polyamide resin composition (C) and the ammonium salt (C) 3 via the component (D), as shown in FIG. 4.

[0126] In the present invention, a method for confirming that the carbon fibers (A1) and the organic fibers (A2) are unevenly distributed in the fiber bundle may include, for example, observing a cross section of the molding material perpendicular to the longitudinal direction of the fibers with an optical microscope set at a magnification of 300 times, and then processing and analyzing the obtained microscopic image.

[0127] As a method for unevenly distributing the carbon fibers (A1) and the organic fibers (A2) in the cross section of the fiber bundle, there is a method of preparing the molding material by aligning bundles of the carbon fibers (A1) and bundles of the organic fibers (A2). By aligning the respective bundles to prepare the molding material, the carbon fibers (A1) and the organic fibers (A2) exist as independent fiber bundles, and uneven distribution can be achieved. Increasing the number of single fibers in the bundles of the carbon fibers (A1) and the organic fibers (A2) used makes the bundles larger, and decreasing the number of single fibers makes the bundles smaller, and uneven distribution can be achieved by changing the size of the bundles.

[0128] The carbon fiber (A1) is not particularly limited, but a fiber bundle containing 100 to 350,000 carbon fibers is preferably used, and from the viewpoint of productivity, a fiber bundle containing 20,000 to 100,000 fibers is more preferable. On the other hand, when polyester fiber or liquid crystal polyester fiber is used as the organic fiber (A2), there is no particular limitation, but a fiber bundle containing 1 to 2,000 fibers is preferably used, and from the viewpoint of productivity and suppressing entanglement of fibers in a molded article, a fiber bundle containing 10 to 1,000 fibers is more preferable, and a fiber bundle containing 30 to 700 fibers is even more preferable.

[0129] By molding using the above molding material, it is possible to obtain a molded article that is excellent in dispersibility of the carbon fibers (A1) and the organic fibers (A2), moldability, flexural strength, and impact properties.

[0130] Next, a method for producing the molding material will be described. The molding material of the present invention can be obtained, for example, by the following method.

[0131] First, a roving of carbon fiber (A1) and a roving of organic fiber (A2) are doubling in parallel in the longitudinal direction of the fibers to produce a fiber bundle containing carbon fiber (A1) and organic fiber (A2). Next, the fiber bundle is impregnated with molten component (D) to produce a composite fiber bundle (E). The composite fiber bundle (E) is then introduced into an impregnation die filled with a composition containing molten polyamide resin composition (B) and ammonium salt (C), and the polyamide resin composition (B) and ammonium salt (C) coat the exterior of the composite fiber bundle (E), which is then drawn through a nozzle. After cooling and solidifying, the composite fiber bundle is pelletized to a predetermined length to obtain a molding material. The polyamide resin composition (B) and ammonium salt (C) may be impregnated into the fiber bundle, as long as they are disposed at least on the exterior of the composite fiber bundle (E).

[0132] A molding material mixture may be obtained by pellet-blending a molding material obtained by coating a composite fiber bundle (E) with a polyamide resin composition (B) and an ammonium salt (C) produced by the above-mentioned method with pellets containing the polyamide resin composition (B) (not including carbon fiber (A1) or organic fiber (A2)). This makes it easy to adjust the contents of carbon fiber (A1) and organic fiber (A2) in a molded product. Pellet blending differs from melt kneading in that multiple materials are stirred and mixed at a temperature at which the resin components do not melt, resulting in a substantially homogeneous mixture. This method is preferably used when using a pellet-shaped molding material, such as in injection molding or extrusion molding.

[0133] Next, a method for producing the molded article of the present invention will be described. Molded articles excellent in moldability, bending properties, impact properties, and appearance quality can be obtained by molding using the molding material of the present invention. Molding methods using a mold are preferred, and various molding methods such as injection molding, extrusion molding, and press molding can be used. Molded articles can be obtained continuously and stably, particularly by molding using an injection molding machine. While there are no particular restrictions on injection molding conditions, for example, the injection time is preferably 0.5 to 10 seconds, more preferably 2 to 10 seconds. The back pressure is preferably 0.1 MPa or more, more preferably 1 MPa or more, even more preferably 2 MPa or more, and most preferably 3 MPa or more. The upper limit is preferably 50 MPa or less, more preferably 30 MPa or less, even more preferably 20 MPa or less, and most preferably 10 MPa or less. The injection speed is preferably 1 mm / s to 200 mm / s, more preferably 10 mm / s to 150 mm / s, and even more preferably 20 mm / s to 100 mm / s. The screw rotation speed is preferably 10 rpm to 200 rpm, more preferably 30 rpm to 150 rpm, and even more preferably 50 rpm to 100 rpm. The dwell pressure is preferably 1 MPa to 50 MPa, more preferably 1 MPa to 30 MPa. The dwell time is preferably 1 second to 20 seconds, more preferably 5 seconds to 20 seconds. The cylinder temperature is preferably 200°C to 320°C, and the mold temperature is preferably 20°C to 100°C. Here, the cylinder temperature refers to the temperature of the part of the injection molding machine where the molding material is heated and melted, and the mold temperature refers to the temperature of the mold into which the resin is injected to form the desired shape. By appropriately selecting these conditions, particularly the injection time, back pressure, and mold temperature, the fiber length of carbon fibers such as carbon fibers and organic fibers in the molded product can be easily adjusted.

[0134] The molded article of the present invention obtained as described above has excellent moldability, mechanical properties, particularly bending strength and impact resistance, and appearance quality. [Example]

[0135] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the descriptions of these examples. First, the methods for evaluating various properties used in the examples will be described.

[0136] (1) Measurement of weight average fiber length A 0.5 cm square test piece cut from an ISO dumbbell test piece obtained in each Example and Comparative Example was sandwiched between cover glasses and heated on a hot stage set at a temperature (e.g., 200 to 300°C) at which only the polyamide resin composition (B) melts, without melting the organic fiber (A2). The test piece was formed into a film without applying excessive pressure, resulting in a uniformly dispersed fiber. The film in which the carbon fiber (A1) and organic fiber (A2) were uniformly dispersed was observed under an optical microscope (50 to 200 magnifications). The fiber lengths of 1,000 randomly selected carbon fibers (A1) and 1,000 randomly selected organic fibers (A2) were measured, and the weight-average fiber length was calculated using the following formula: Average fiber length = Σ(Mi 2 ×Ni) / Σ(Mi×Ni) Mi: Fiber length (mm) Ni: Number of fibers with fiber length Mi.

[0137] (2) Measurement of bending strength and bending modulus of molded products, bending modulus when absorbing water The flexural strength and flexural modulus of the ISO dumbbell test specimens obtained in each Example and Comparative Example were measured in accordance with ISO 178:2010, Amd.1:2013 using a three-point bending test jig (indenter radius 5 mm) with a support distance of 64 mm and a test speed of 2 mm / min. The tester used was an Instron (registered trademark) universal testing machine, Model 5566 (manufactured by Instron Corporation). Measurements were performed three times, and the average values were calculated as the flexural strength and flexural modulus of each Example and Comparative Example. The flexural modulus was calculated from the stress gradient in the specified strain range (0.05 to 0.25%). The flexural modulus of elasticity of the water-absorbed ISO dumbbell test pieces described below was also measured in the same manner as above.

[0138] (3) Charpy impact strength measurement of molded products A parallel section was cut out from the ISO dumbbell test piece obtained in each example and comparative example, and a V-notch Charpy impact test was carried out in accordance with ISO 179 using a C1-4-01 model testing machine manufactured by Tokyo Testing Machine Co., Ltd. Measurements were carried out five times, and the average value was calculated as the impact strength (kJ / m) of each example and comparative example. 2 ) was calculated as

[0139] (4) Evaluation of fiber dispersion in molded products For each of the 80 mm × 80 mm × 3 mm thick test pieces obtained in each of the Examples and Comparative Examples, the number of undispersed carbon fiber bundles (CF bundles) present on both the front and back surfaces was visually counted. Evaluation was carried out for 50 molded products, and the fiber dispersion of the total number was judged according to the following criteria, with A and B being considered as passing. A: Less than 1 undispersed CF bundle B: 1 or more but less than 3 undispersed CF bundles C: 3 or more undispersed CF bundles.

[0140] (5) Liquidity assessment The fiber-reinforced polyamide resin composition pellets were vacuum-dried at 80°C for 12 hours and injection-molded using an injection molding machine (J110AD manufactured by The Japan Steel Works, Ltd.) under the following conditions: cylinder temperature: polyamide resin melting point + 15°C, mold temperature: 80°C, injection speed: 60 mm / sec, injection pressure: 60 MPa. A 10 mm wide x 150 mm long x 1.0 mm long mold was used to prepare a 10 mm wide x 1.0 mm thick rod flow test piece. The rod flow length at 0 dwell pressure was measured five times, and the average value was calculated to evaluate the fluidity. A longer flow length indicates better fluidity.

[0141] (6) Morphology observation The center of the cross section of a JIS-5A dumbbell-shaped test specimen or bending test specimen obtained by injection molding was cut into 1-2 mm squares and stained with ruthenium tetroxide to stain the resin (B2) having reactive functional groups. The test specimen was cut using an ultramicrotome at -196°C to obtain ultrathin sections with a thickness of 0.1 μm or less (approximately 80 nm). The sections were observed using a transmission electron microscope. The number-average particle size (Xn) was calculated by randomly extracting 400 or more particles from the obtained image, analyzing the particle size distribution using Scion Corporation's image analysis software "Scion Image," and using the following formula: Number average particle diameter (Xn)=Σ(Xi×ni) / Σni Xi: particle diameter ni: Number of particles corresponding to particle diameter (Xi) (i=1, 2, 3, . . . , n)

[0142] The number average particle diameter of the particles made of resin (B2) is shown in the image magnified 10,000 times. The number average particle size of the fine particles in the particles consisting of resin (B2) was calculated from an image magnified 35,000 times. The number average particle size of the particles consisting of resin (B2), the presence or absence of fine particles of 1 to 100 nm of compound (B3), and the presence or absence of fine particles exceeding 300 nm were confirmed.

[0143] Furthermore, the area ratio occupied by compound (B3) was calculated by analyzing the area of resin (B2) and the area occupied by compound (B3) from the image magnified 35,000 times using a transmission electron microscope, using image analysis software "Scion Image" manufactured by Scion Corporation, and then calculating the area ratio by the following formula. Sn = Sp / (Sa2 + Sp) Sn: Area ratio of compound (B3) in particles made of resin (B2) Sa2: Area occupied by resin (B2) Sp: Area occupied by compound (B3).

[0144] (7) Water absorption measurement The ISO dumbbell test pieces obtained in each example and comparative example were left to stand in a thermostatic chamber at 23°C and 50% humidity for 24 hours, after which they were weighed and then left in an environment of 80°C and 95% RH for 24 hours.The water from the obtained water-absorbed ISO dumbbell test pieces was then wiped off and the weight was weighed, and the water absorption rate of the ISO dumbbell test pieces before and after water absorption was calculated.

[0145] <Carbon fiber (A1)> Reference Example 1: Preparation of carbon fiber (A1) The fiber is made from a copolymer primarily composed of polyacrylonitrile, spun, baked, and surface-oxidized. The total number of single fibers is 24,000, the single fiber diameter is 7 μm, the mass per unit length is 1.6 g / m, and the specific gravity is 1.8 g / cm. 3 This resulted in continuous carbon fibers with a surface oxygen concentration ratio [O / C] of 0.2. The strand tensile strength of this continuous carbon fiber was 4,880 MPa, and the strand tensile modulus was 225 GPa. Next, a sizing agent mother solution was prepared by dissolving glycerol polyglycidyl ether (a polyfunctional compound) in water to a concentration of 2% by weight. The sizing agent was applied to the carbon fibers by immersion, and the fibers were dried at 230°C. The amount of sizing agent attached to the carbon fibers thus obtained was 1.0% by weight.

[0146] Reference Example 2: Preparation of dendritic polyester (C-3) A 500 mL reaction vessel equipped with a stirring blade and a distillation tube was charged with 51.93 g (0.38 mol) of p-hydroxybenzoic acid, 19.1 g (0.10 mol) of 4,4'-dihydroxybiphenyl, 5.86 g (0.035 mol) of terephthalic acid, 21.2 g (0.10 mol) of trimesic acid, 5.55 g (0.045 mol) of benzoic acid, 11.3 g (0.059 mol) of polyethylene terephthalate having an intrinsic viscosity of approximately 0.6 dL / g, and 65.3 g of acetic anhydride (1.10 equivalents of the total of phenolic hydroxyl groups), and the mixture was reacted at 150°C for 1.5 hours with stirring under a nitrogen gas atmosphere. The temperature was raised to 290°C over 3 hours, and then the pressure was reduced to 1.0 mmHg (133 Pa) over 30 minutes while maintaining the polymerization temperature at 290°C. When the stirring torque reached 2.5 kg·cm, the polymerization reaction was stopped and the contents were poured into water. The resulting dendritic polyester (C-1) was dried by heating at 110°C for 4 hours, then pulverized in a blender and washed with ethanol and deionized water. It was then vacuum-dried at 110°C for 24 hours in a vacuum oven to obtain powdered dendritic polyester (C-3).

[0147] <Organic Fiber (A2)> (A2-1): Liquid crystal polyester fiber (Toray Industries, Inc., "Scivelas" (registered trademark) 1700T-288f, strength: 23.5 cN / dtex, melting point: 330°C) was used. (A2-2): Polyester fiber (manufactured by Toray Industries, Inc., "Tetoron (registered trademark)" 2200T-480-705M, single fiber fineness: 4.6 dtex, melting point: 260°C) was used. (A2-3): Polyphenylene sulfide fiber ("TORCON" (registered trademark) 400T-100-190, manufactured by Toray Industries, Inc., single fiber fineness 4.0 dtex, melting point 285°C) was used. (A2-4): Polytetrafluoroethylene fiber (Toray Industries, Inc. "Toyoflon" (registered trademark) 440T-60F-S290-M190, single fiber fineness 7.3 dtex, melting point 327°C) was used.

[0148] <Polyamide resin composition (B)> Polyamide resin (B1a) (B1a-1): Nylon 6 resin having a melting point of 225°C and a relative viscosity of 2.75 at 0.01 g / ml in 98% sulfuric acid. (B1a-2): Nylon 66 resin having a melting point of 265°C and a relative viscosity of 3.60 at 0.01 g / ml in 98% sulfuric acid. (B1a-3): Nylon 610 resin having a melting point of 225°C and a relative viscosity of 2.70 at 0.01 g / ml in 98% sulfuric acid. Polyamide resin (B1b) (B1b-1): Melting point 225 ° C., relative viscosity 2.70 at 0.01 g / ml in 98% sulfuric acid Nylon 610 resin. (B1b-2): Nylon 11 resin having a melting point of 190°C and a relative viscosity of 2.55 at 0.01 g / ml in 98% sulfuric acid. (B1b-3): Nylon 12 resin having a melting point of 180°C and a relative viscosity of 2.55 at 0.01 g / ml in 98% sulfuric acid.

[0149] Resin with reactive functional groups (B2) (B2-1): Glycidyl methacrylate modified polyethylene copolymer "Bondfast (registered trademark) BF-7L" (manufactured by Sumitomo Chemical Co., Ltd.). (B2-2): Glycidyl methacrylate modified polyethylene copolymer "Bondfast (registered trademark) BF-7M" (manufactured by Sumitomo Chemical Co., Ltd.). (B2-3): Maleic anhydride-modified ethylene-1-butene copolymer "TAFMER (registered trademark) MH7020" (manufactured by Mitsui Chemicals, Inc.). (B2-4): Ethylene-methacrylic acid-zinc methacrylate copolymer "Himilan (registered trademark) 1706" (manufactured by DuPont-Mitsui Polychemicals Co., Ltd.). (B2-5): Oxazoline group-containing reactive polystyrene "Epocross (registered trademark) RPS-1005" (manufactured by Nippon Shokubai Co., Ltd.).

[0150] <Ammonium salt (C), or flow modifier (C) used in comparative examples (C-2 and C-3)> (C-1): Diammonium adipate (Fujifilm Wako Pure Chemical Industries, Ltd.) (C-2): Adipic acid (Fujifilm Wako Pure Chemical Industries, Ltd.) (C-3): Dendritic polyester obtained in Reference Example 2

[0151] <Ingredient (D)> (D-1) A solid terpene phenol resin ("Mighty Ace" (registered trademark) K125, manufactured by Yasuhara Chemical Co., Ltd., softening point 125°C) was used.

[0152] Example 1 A long-fiber-reinforced resin pellet manufacturing apparatus was used, equipped with a Japan Steel Works, Ltd. TEX-30α twin-screw extruder (screw diameter 30 mm, L / D = 32 mm) equipped with a coating die for wire coating. The extruder cylinder temperature was set to 270°C, and the polyamide resin composition (B1-1), resin (B2-1), and ammonium salt (C-1) described above were fed from the main hopper and melt-kneaded at a screw rotation speed of 200 rpm. A fiber bundle consisting of carbon fiber (A1) and organic fiber (A2) was fed into a die opening (diameter 3 mm) from which a composition containing molten polyamide resin (B1-1), resin (B2-1), and ammonium salt (C-1) was discharged, so that the carbon fiber (A1) and organic fiber (A2) were continuously coated with the composition containing molten polyamide resin (B1-1), resin (B2-1), and ammonium salt (C-1). At this time, the carbon fiber (A1) and the organic fiber (A2) were unevenly distributed in the internal cross section of the composite fiber bundle (E). As shown in FIG. 3, the uneven distribution state was such that at least a portion of each of the carbon fiber (A1) and the organic fiber (A2) was in contact with the composition containing the molten polyamide resin (B1-1), the resin (B2-1), and the ammonium salt (C-1). The resulting strand was cooled and then cut with a cutter to a pellet length of 7 mm to obtain long fiber pellets. The take-up speed was adjusted so that the reinforcing fiber (A) was 25 parts by weight per 100 parts by weight of the total of (A) to (C) (80 parts by weight of carbon fiber (A1) and 20 parts by weight of organic fiber (A2) per 100 parts by weight of reinforcing fiber (A)). The lengths of the carbon fiber (A1) and the organic fiber (A2) in the obtained long fiber pellets were substantially the same as the pellet length.

[0153] The resulting long fiber pellets were injection-molded using an injection molding machine (J110AD, manufactured by The Japan Steel Works, Ltd.) under the following conditions: injection time: 2 seconds, back pressure: 5 MPa, dwell pressure: 40 MPa, dwell time: 10 seconds, injection speed: 30 mm / s, screw rotation speed: 80 rpm, cylinder temperature: 270°C, and mold temperature: 80°C. This resulted in the production of ISO dumbbell test specimens (Type A1) and 80 mm x 80 mm x 3 mm test specimens. Here, the cylinder temperature refers to the temperature of the injection molding machine's part where the molding material is heated and melted, and the mold temperature refers to the temperature of the mold where the resin is injected to form the desired shape. The resulting test specimens (molded products) were left to stand for 24 hours in a constant-temperature, constant-humidity chamber adjusted to 23°C and 50% RH before undergoing property evaluation. The evaluation results obtained using the above-mentioned methods are summarized in Table 1.

[0154] (Examples 2 to 5, 7 to 17, 31 to 35, 41 to 54, and 56) Molded articles were produced and evaluated in the same manner as in Example 1 (the cylinder temperature was set to 280°C in Example 13), except that the composition ratio or the type of fiber used was changed as shown in Tables 1 and 2. The evaluation results are summarized in Tables 1, 2, 3, 4, and 5.

[0155] Example 6 Except for changing the molding back pressure during injection molding to 10 MPa, a molded article was produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

[0156] (Examples 18 to 30, 38 to 40, 55, and 57) A long fiber reinforced resin pellet manufacturing device was used, which was a Japan Steel Works, Ltd. TEX-30α type twin-screw extruder (screw diameter 30 mm, L / D = 32) equipped with a coating die for the electric wire coating method at the tip. The extruder cylinder temperature was set to 270°C, and the polyamide resin composition (B1-1), resin (B2-1), and ammonium salt (C-1) shown above were fed from the main hopper and melt-kneaded at a screw rotation speed of 200 rpm. The component (D-1) was melted at 200°C and the amount of extrusion was adjusted to 8 parts by weight per 100 parts by weight of the total of (A) to (C). This was applied to a fiber bundle consisting of carbon fiber (A1) and organic fiber (A2) to form a composite fiber bundle (E). The composite fiber bundle (E) was then fed into a die opening (diameter 3 mm) that extruded a composition containing molten polyamide resin (B1-1), resin (B2-1), and ammonium salt (C-1). The carbon fiber (A1) and organic fiber (A2) were continuously coated with the composition containing molten polyamide resin (B1-1), resin (B2-1), and ammonium salt (C-1). The carbon fiber (A1) and organic fiber (A2) were unevenly distributed in the internal cross section of the composite fiber bundle (E). As shown in Figure 3, the uneven distribution state was such that at least a portion of each of the carbon fiber (A1) and the organic fiber (A2) was in contact with the composition containing the molten polyamide resin (B1-1), the resin (B2-1), and the ammonium salt (C-1). The resulting strand was cooled and then cut into pellets 7 mm long with a cutter to obtain long fiber pellets. A molded article was produced and evaluated in the same manner as in Example 1. The evaluation results are summarized in Tables 2, 3, 4, and 5.

[0157] Example 36 Except for changing the molding back pressure during injection molding to 7 MPa, a molded article was produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 3.

[0158] Example 37 Except for changing the molding back pressure during injection molding to 3 MPa, molded articles were produced and evaluated in the same manner as in Example 1. The evaluation results are summarized in Table 4.

[0159] (Comparative Examples 1 to 7, 9 to 11) Molded articles were produced and evaluated in the same manner as in Example 1, except that the composition was changed as shown in Table 6. The evaluation results are shown in Table 6.

[0160] (Comparative Example 8) Except for changing the molding back pressure during injection molding to 40 MPa, a molded article was produced and evaluated in the same manner as in Example 1. The evaluation results are summarized in Table 6.

[0161] [Table 1]

[0162] [Table 2]

[0163] [Table 3]

[0164] [Table 4]

[0165] [Table 5]

[0166] [Table 6]

[0167] The molded articles of the Examples exhibited high bending strength and impact properties, and the inclusion of ammonium salt (C) resulted in excellent fluidity and excellent fiber dispersion. In Examples 5 to 51 and 53 to 57, the reinforcing fibers (A) contained carbon fibers (A1) and organic fibers (A2), which resulted in particularly high impact strength of the molded articles. Furthermore, in Examples 31 to 51 and 56 and 57, in which the polyamide resin (B1) contained polyamide resin (B1a) and polyamide resin (B1b), the water absorption rate of the molded articles was reduced, thereby suppressing the decrease in rigidity upon water absorption, and further resulting in excellent fiber dispersion and high impact properties. Furthermore, in Examples 6, 36, and 37, in which the molding back pressure was changed, similar excellent effects were also achieved. Furthermore, in Examples 18 to 30, 38 to 40, 55, and 57, which contained component (D), the dispersion of carbon fibers (A1) and organic fibers (A2) was excellent, resulting in particularly high bending strength and impact properties. Examples 25 to 30 and 46 to 51, in which the type of organic fiber was changed, also showed high bending strength and impact properties, and because they contained ammonium salt (C) and polyamide resin (B1b), they were able to reduce the water absorption rate of the molded article and suppress the decrease in rigidity when absorbing water, and also were able to exhibit excellent fluidity and excellent fiber dispersibility.

[0168] On the other hand, in Comparative Examples 1 and 6, the absence of ammonium salt (C) resulted in poor fluidity and fiber dispersion of the molded article. In Comparative Example 2, the absence of resin (B2) resulted in poor impact strength. In Comparative Example 3, the amount of carbon fiber (A1) contained was small, resulting in poor reinforcing effect and reduced mechanical properties of the molded article. In Comparative Examples 4 and 5, the excess carbon fiber (A1) or organic fiber (A2) contained caused breakage due to contact between fibers, shortening the remaining fiber length and resulting in low impact strength.

[0169] In Comparative Example 7, the inclusion of an excessive amount of ammonium salt (C) accelerated plasticization of the polyamide resin composition (B), resulting in poor mechanical properties. In Comparative Example 8, the back pressure during molding was set high, resulting in a short remaining fiber length of the reinforcing fibers (A), resulting in poor mechanical properties. In Comparative Example 9, the number average particle diameter of the resin (B2) was not controlled within the range of 10 to 1,000 nm, resulting in poor impact properties. In Comparative Example 10, the absence of ammonium salt (C) and the use of only adipic acid accelerated decomposition of the polyamide resin composition (B), resulting in poor mechanical properties. In Comparative Example 11, the use of a flow modifier other than the ammonium salt (C) resulted in poor fiber dispersion. [Explanation of symbols]

[0170] 1 Carbon fiber (A1) 2 Organic Fibers (A2) 3. Polyamide resin composition (B) and ammonium salt (C) 4 Ingredients (D)

Claims

1. A fiber-reinforced polyamide resin composition molded article comprising 5 to 50 parts by weight of reinforcing fibers (A), 40 to 94.9 parts by weight of a polyamide resin composition (B), and 0.1 to 10 parts by weight of an ammonium salt (C) composed of an aliphatic dicarboxylic acid having 6 to 12 carbon atoms and ammonia, wherein the weight-average fiber length (Lwa1) of the reinforcing fibers (A) is 0.4 to 7 mm, the polyamide resin composition (B) is composed of a polyamide resin (B1), a resin (B2) having a reactive functional group, and a compound (B3) produced by the reaction of the polyamide resin (B1) with the resin (B2), the resin (B2) being dispersed in the form of particles with a number-average particle diameter of 10 to 1,000 nm, the polyamide resin (B1) contained in the polyamide resin composition (B) forming a continuous phase, the resin (B2) forming a dispersed phase, and the dispersed phase containing fine particles of the compound (B3) having a particle diameter of 1 to 100 nm.

2. 2. The fiber-reinforced polyamide resin composition molded article according to claim 1, wherein the area ratio of the fine particles made of the compound (B3) to the particles made of the resin (B2) is 20% or more.

3. 3. The fiber-reinforced polyamide resin composition molded article according to claim 1 or 2, wherein the resin (B2) is a resin having at least one reactive functional group selected from an amino group, a carboxyl group, a metal salt of a carboxyl group, an epoxy group, an acid anhydride group, and an oxazoline group.

4. The fiber-reinforced polyamide resin composition molded article according to any one of claims 1 to 3, wherein the resin (B2) is a polyolefin resin.

5. The fiber-reinforced polyamide resin composition molded article according to any one of claims 1 to 4, wherein the reinforcing fibers (A) comprise carbon fibers (A1) and organic fibers (A2), and the carbon fibers (A1) are contained in an amount of 50 to 99 parts by weight and the organic fibers (A2) are contained in an amount of 1 to 50 parts by weight per 100 parts by weight of the total of the carbon fibers (A1) and the organic fibers (A2).

6. The fiber-reinforced polyamide resin composition molded article according to claim 5, wherein the weight average fiber length (Lwa2) of the organic fibers (A2) is 3 to 7 mm.

7. The fiber-reinforced polyamide resin composition molded article according to any one of claims 1 to 6, wherein the polyamide resin (B1) is a mixture of a polyamide resin (B1a) selected from polyamide 6 and polyamide 66, and one or more polyamide resins (B1b) selected from the group consisting of polyamide 610, polyamide 612, polyamide 11, polyamide 12, polyamide 1010, polyamide 1012, and polyamide 9T, and copolymer polyamides containing at least one of these as a constituent component.

8. 8. The fiber-reinforced polyamide resin composition molded article according to claim 7, wherein the polyamide resin (B1) is a mixture of polyamide 6 resin and polyamide 610 resin.

9. 9. The molded article of fiber-reinforced polyamide resin composition according to claim 7 or 8, which has a water absorption rate of 3.0% or less when left in an environment of 80°C x 95% RH for 24 hours.

10. 7. The fiber-reinforced polyamide resin composition molded article according to claim 5, wherein the organic fiber (A2) is at least one selected from the group consisting of a liquid crystal polyester fiber, a polyarylene sulfide fiber, and a fluorine fiber.

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