Resin-impregnated fiber bundle, resin composition, molded article and method for producing molded article, press molded article and method for producing press molded article

Abstract

To provide resin-impregnated fiber bundles capable of producing small molded articles with higher mechanical strength and good appearance, as well as resin compositions containing such fiber bundles, molded articles, and a method for manufacturing the same, and to provide press molded articles with higher mechanical strength and improved appearance, and a method for manufacturing the same.SOLUTION: There are provided resin-impregnated fiber bundles (X), wherein the resin-impregnated fiber bundles (X) are fiber bundles (A1) in which cellulose fibers (A) are bundled in the longitudinal direction and impregnated with a thermoplastic resin (B) and the length of the resin-impregnated fiber bundles (X) is longer than 30 mm and equal to or shorter than 1000 mm. There are also provided press molded articles, wherein the pressed molded articles are embedded in the thermoplastic resin (B) with cellulose fibers (A) of longer than 30 mm and equal to or shorter than 1,000 mm arranged parallel to one direction of the pressed molded articles.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin-impregnated fiber bundle, a resin composition, a molded article and a method for producing the same, and a press-molded article and a method for producing the same. [Background technology]

[0002] Conventionally, a method has been known in which pellets of a fiber-reinforced resin composition containing a thermoplastic resin and a reinforcing fiber (filler) are injection-molded to obtain a molded article. However, when such pellets are used in injection molding, the filler may break during the injection molding process, resulting in a decrease in the reinforcing effect. In response to this, for example, Patent Documents 1 and 2 discuss the use of press molding instead of injection molding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3631994 [Patent Document 2] Patent No. 4743592 Summary of the Invention [Problem to be solved by the invention]

[0004] That is, press molding is sometimes used instead of injection molding to manufacture molded products that require higher mechanical strength. This is because press molding makes it easier to prevent the filler from breaking during molding, thereby reducing the reinforcing effect. However, when small molded products are manufactured by press molding, there are problems such as the resin and filler not filling the edges of the small molded product, reducing the strength of the edges, and the rib shape designed to improve strength is not sufficiently filled with resin, making it difficult to shape, making it difficult to obtain molded products with high mechanical strength. In addition, with small molded products, there are problems such as fillers such as glass fibers protruding from the surface of the molded product, which deteriorates the appearance.

[0005] Therefore, a first object of the present invention is to provide a resin-impregnated fiber bundle that can be used to produce small molded products with higher mechanical strength and good appearance, a resin composition containing the same, a molded product, and a method for producing the same.A second object of the present invention is to provide a press-molded product with higher mechanical strength and good appearance, and a method for producing the same. [Means for solving the problem]

[0006] As a result of extensive research, the inventors of the present application have found that the first problem can be solved by a resin-impregnated fiber bundle obtained by impregnating a fiber bundle of cellulose fibers aligned in the length direction and bundled together with a thermoplastic resin, wherein the length of the resin-impregnated fiber bundle is more than 30 mm and not more than 1000 mm, and a resin composition containing the resin-impregnated fiber bundle.

[0007] Furthermore, the inventors have found that the second problem can be solved by a press-molded product in which cellulose fibers having a length of more than 30 mm and no greater than 1000 mm are embedded in a thermoplastic resin while being arranged so as to be parallel to one direction of the molded product, and a method for manufacturing such a press-molded product, which includes arranging the resin-impregnated fiber bundles so as to be parallel to one direction of a mold and press-molding the resin-impregnated fiber bundles. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a resin-impregnated fiber bundle that can be used to produce small molded articles having higher mechanical strength and good appearance, a resin composition containing the same, a molded article, and a method for producing the same. It is also possible to provide a press-molded article having higher mechanical strength and good appearance and a method for producing the same. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present disclosure will be described in detail below. However, the scope of the present disclosure is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the present disclosure. Each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. Furthermore, when multiple upper and lower limits are described for a specific parameter, any of these upper and lower limits can be combined to form a suitable numerical range. Furthermore, the lower and / or upper limits of a numerical range described in this disclosure are numerical values within that range and may be replaced with numerical values shown in the examples. An expression such as "1 to 10" indicating a numerical range means "1 or more and 10 or less." If a specific description described for one embodiment also applies to other embodiments, that description may be omitted in other embodiments.

[0010] The configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible as appropriate within the scope of the gist of the present disclosure. The present disclosure is not limited to the embodiments. Each feature disclosed herein may be combined with any other feature disclosed herein.

[0011] [Resin-impregnated fiber bundle (X)] The first embodiment of the present disclosure relates to a resin-impregnated fiber bundle (X). The first embodiment relates to a resin-impregnated fiber bundle (X), which is obtained by impregnating a fiber bundle (A1) of cellulose fibers (A) aligned in the length direction with a thermoplastic resin (B), and the length of the resin-impregnated fiber bundle (X) is more than 30 mm and 1000 mm or less. The resin-impregnated fiber bundle (X) according to the first embodiment allows the production of small molded products having higher mechanical strength and good appearance.

[0012] The length of the resin-impregnated fiber bundle (X) according to the first embodiment is more than 30 mm and not more than 1000 mm. The length of the resin-impregnated fiber bundle (X) can be set arbitrarily within the above range depending on the shape (length, width, etc.) of the small molded product. In one embodiment, it may be set to the same length as the length or width of the small molded product. The "length of the small molded product" may be the length in the longitudinal direction of the small molded product, or the length of the longest part in the longitudinal direction. The "width of the small molded product" may be the length in the lateral direction of the small molded product, or the length of the shortest part in the lateral direction.

[0013] In one embodiment, the length of the resin-impregnated fiber bundle (X) may be more than 50 mm and not more than 1000 mm, may be 70 to 900 mm, may be 100 to 900 mm, or may be 200 to 800 mm. In one embodiment, the length of the resin-impregnated fiber bundle (X) may be 100 to 500 mm, may be more than 150 mm and not more than 1000 mm, may be 200 to 1000 mm, or may be 500 to 1000 mm. The length of the resin-impregnated fiber bundle (X) can be determined by measuring the resin-impregnated fiber bundle (X) with a vernier caliper or the like.

[0014] <Fiber bundle (A1)> The resin-impregnated fiber bundle (X) according to the first embodiment includes a fiber bundle (A1) in which cellulose fibers (A) are aligned in the length direction and bundled together. The number of cellulose fibers (A) in the fiber bundle (A1) can be adjusted in consideration of the outer diameter (long axis length and short axis length) of the fiber bundle (A1). The number of cellulose fibers (A) is preferably adjusted to a range of 100 to 30,000 from the viewpoints of facilitating impregnation of the thermoplastic resin (B) up to the center of the fiber bundle (A1), preventing production problems such as fiber bundle breakage during production of the fiber bundle (A1), and of facilitating production of the resin-impregnated fiber bundle (X) and / or enabling molded articles to be molded using fewer resin-impregnated fiber bundles (X), thereby improving productivity of molded articles. In one embodiment, the number of cellulose fibers (A) may be 300 to 15,000, 300 to 10,000, or 300 to 5,000. In particular, when the cellulose fibers (A) are regenerated cellulose fibers described below, the above effects are more easily achieved by bundling 100 to 30,000 fibers (more preferably 300 to 10,000 fibers) of the regenerated cellulose in the lengthwise direction to form a fiber bundle.

[0015] (Cellulose fiber (A)) The fiber bundle (A1) contains cellulose fibers (A). Cellulose is a plant-derived polysaccharide found in, for example, wood, cotton, ramie, linen, hemp, jute, Manila hemp, sisal, etc. The cellulose fibers (A) contained in the resin-impregnated fiber bundle (X) according to the first embodiment are long fibers (continuous fibers). The continuous cellulose fibers may be, for example, natural cellulose fibers (short fibers) extracted from plants such as cotton, ramie, linen, hemp, jute, Manila hemp, sisal, etc., twisted together to form a long thread (continuous natural cellulose fibers (spun fibers)), or continuous regenerated cellulose fibers. They may also be monofilaments or multifilaments. The natural continuous cellulose fibers may contain lignin, hemicellulose, etc., but the cellulose content is preferably 60% or more, more preferably 60 to 80%.

[0016] The length of the cellulose fibers (A) in the resin-impregnated fiber bundle (X) is the same as the length of the resin-impregnated fiber bundle (X). That is, the length of the cellulose fibers (A) in the resin-impregnated fiber bundle (X) is more than 30 mm and not more than 1000 mm.

[0017] The average fiber diameter of the cellulose fibers (A) is preferably 5 to 30 μm. The average fiber diameter of the cellulose fibers (A) can be calculated by observing the fiber diameters (long diameters) of a plurality of cellulose fibers (A) with an SEM or the like and averaging the observed values.

[0018] The degree of X-ray orientation of the cellulose fibers (A) may be 90% or more. By including such cellulose fibers (A), small molded articles having superior mechanical strength can be produced.

[0019] In one embodiment, the cellulose fibers (A) preferably contain regenerated cellulose fibers, and more preferably contain only regenerated cellulose fibers. Hereinafter, the regenerated cellulose fibers used in the first embodiment will be described in detail.

[0020] (regenerated cellulose fiber) "Regenerated cellulose fiber" refers to artificially spun cellulose fibers using natural cellulose fibers (such as the aforementioned plant-derived cellulose fibers, animal-derived cellulose fibers (such as sea squirt cellulose), and bacterial-derived cellulose fibers). Methods for obtaining regenerated cellulose fibers from natural cellulose fibers include, for example, the viscose method, the cuprammonium method, and the solvent spinning method (a method in which cellulose is directly spun without first being chemically converted). Examples of regenerated cellulose fibers obtained by the viscose method include viscose rayon, polynosic, and modal. Examples of regenerated cellulose fibers obtained by the cuprammonium method include cupra. Examples of regenerated cellulose fibers obtained by the solvent spinning method include lyocell and regenerated cellulose fibers obtained by the ionic liquid method. As the regenerated cellulose fibers, one type of regenerated cellulose fiber obtained by these methods may be used alone, or two or more types may be used in combination. Spun fibers obtained by twisting short regenerated cellulose fibers into long threads may also be used.

[0021] In one embodiment, the cellulose fibers (A) preferably include regenerated cellulose fibers obtained by the viscose method and / or regenerated cellulose fibers obtained by the solvent method (hereinafter referred to as "solvent-process regenerated cellulose fibers"), more preferably include solvent-process regenerated cellulose fibers, and particularly preferably include only solvent-process regenerated cellulose fibers.

[0022] The length of the regenerated cellulose fiber in the resin-impregnated fiber bundle (X) is more than 30 mm and not more than 1000 mm. Since the length of the regenerated cellulose fiber is the same as that of the resin-impregnated fiber bundle (X), it can be any length from more than 30 mm to not more than 1000 mm.

[0023] In one embodiment, the average fiber diameter of the regenerated cellulose fibers is preferably 5 to 30 μm, more preferably 6 to 20 μm, and even more preferably 7 to 15 μm. The average fiber diameter of the regenerated cellulose fibers can be calculated by the method described above for the cellulose fibers (A).

[0024] As described above, the number of regenerated cellulose fibers in the fiber bundle (A1) is preferably adjusted to be in the range of 100 to 30,000. In one embodiment, the number of regenerated cellulose fibers may be 300 to 15,000, 300 to 10,000, or 300 to 5,000.

[0025] In one embodiment, the degree of X-ray orientation of the regenerated cellulose fibers is preferably 90% or more. If the average fiber diameter and degree of X-ray orientation of the regenerated cellulose fibers are within the above ranges, the tensile strength and tensile modulus of the fibers are improved, and the mechanical strength of molded articles obtained from the resin-impregnated fiber bundle (X) is likely to be improved. The degree of X-ray orientation of the regenerated cellulose fibers can be calculated using the formula described in JP-A-9-31744, etc.

[0026] In one embodiment, the tensile modulus (Young's modulus) of the regenerated cellulose fibers may be 10 GPa or more, 13 GPa or more, 15 GPa or more, 20 GPa or more, or 25 GPa or more. The tensile modulus of the regenerated cellulose fibers can be determined by the method described in paragraph 0038 of JP 2013-91775 A, in which "measurement was performed at a chuck distance of 200 mm and a pulling speed of 200 mm / min after storage in an air-conditioned room at 23°C and 50% RH for three weeks."

[0027] In one embodiment, the proportion of the cellulose fibers (A) (preferably regenerated cellulose fibers) to the total mass of the resin-impregnated fiber bundle (X) is preferably 10 to 50 mass%, more preferably 10 to 40 mass%, and even more preferably 20 to 40 mass%. When the proportion of the cellulose fibers (A) (preferably regenerated cellulose fibers) to the total mass of the resin-impregnated fiber bundle (X) is within the above range, the flowability during press molding tends to be good, and small molded products with excellent mechanical strength tend to be obtained.

[0028] <Thermoplastic resin (B)> The resin-impregnated fiber bundle (X) according to the first embodiment contains a thermoplastic resin (B). The thermoplastic resin (B) is not particularly limited as long as it has the effects of the present invention, and any thermoplastic resin can be used. For example, the thermoplastic resin (B) can be an olefin resin, a vinyl alcohol resin, a vinyl ester resin, a styrene resin, a (meth)acrylic resin, a polyester resin, a polycarbonate resin, a polyamide resin, a polysulfone resin, a polyphenylene resin, a polyacetal resin, a thermoplastic elastomer, or the like. Biodegradable resins, biomass resins, or the like can also be used.

[0029] Examples of olefin resins include homopolymers or copolymers of olefins having 2 to 6 carbon atoms (ethylene-based resins such as polyethylene and ethylene-propylene copolymers; propylene-based resins such as polypropylene, propylene-ethylene copolymers, and propylene-butene copolymers; poly(methylpentene-1); propylene-methylpentene copolymers, etc.); copolymers of olefins having 2 to 6 carbon atoms and copolymerizable monomers (ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, etc.); and homopolymers or copolymers of cyclic olefins (particularly cyclic olefins condensed with hydrocarbon rings, bridged cyclic olefins, etc.) that may have a substituent such as an alkyl group or an ester group (for example, homopolymers of cyclic olefins such as polybicyclopentadiene and polynorbornene; copolymers of cyclic olefins selected from bicycloalkadienes, tricycloalkadienes, bicycloalkenes, and tricycloalkenes and α-olefins having 2 to 4 carbon atoms (ethylene, etc.)). These may be used alone or in combination of two or more.

[0030] Examples of vinyl alcohol resins include polyvinyl alcohol, ethylene-vinyl alcohol copolymers, etc. These may be used alone or in combination of two or more.

[0031] Examples of vinyl ester resins (carboxylic acid vinyl ester resins) include homopolymers or copolymers of carboxylic acid vinyl ester monomers such as polyvinyl acetate, and copolymers of carboxylic acid vinyl ester monomers and copolymerizable monomers such as ethylene-vinyl acetate copolymers and vinyl acetate-(meth)acrylic acid ester copolymers. These may be used alone or in combination of two or more.

[0032] Examples of styrene-based resins include homopolymers or copolymers of styrene-based monomers (polystyrene, styrene-α-methylstyrene copolymer, etc.), copolymers of styrene-based monomers with other copolymerizable monomers (styrene-acrylonitrile copolymer (AS resin), styrene-(meth)acrylic acid ester copolymer, styrene-maleic anhydride copolymer, etc.), etc. These may be used alone or in combination of two or more.

[0033] Examples of (meth)acrylic resins include poly(meth)acrylic acid esters such as polymethyl(meth)acrylate, methyl methacrylate-(meth)acrylic acid copolymers, methyl methacrylate-(meth)acrylic acid ester copolymers, methyl methacrylate-(meth)acrylic acid ester-(meth)acrylic acid copolymers, and (meth)acrylic acid ester-styrene copolymers (such as MS resins). These may be used alone or in combination of two or more. Note that (meth)acrylic resins include both methacrylic resins and acrylic resins.

[0034] Examples of polyester resins include homopolyesters or copolyesters having alkylene terephthalate (ethylene terephthalate, butylene terephthalate, etc.) or alkylene naphthalate (ethylene naphthalate, butylene naphthalate, etc.) repeating units (e.g., copolyesters having a copolymerization component of an aliphatic dicarboxylic acid having 6 to 12 carbon atoms such as adipic acid or an asymmetric aromatic dicarboxylic acid such as phthalic acid or isophthalic acid with an alkylene glycol having 2 to 6 carbon atoms, polyoxyalkylene glycol, bisphenol A, etc.); aromatic polyesters (e.g., polyarylate resins produced by reacting an aromatic diol such as bisphenol A with an aromatic dicarboxylic acid such as terephthalic acid); liquid crystalline polyesters; and homopolyesters or copolymers of lactones (e.g., ε-caprolactone). These may be used alone or in combination of two or more.

[0035] Examples of polycarbonate resins include polycarbonates obtained by reacting a dihydroxy compound (e.g., a bisphenol compound such as bisphenol A or bisphenol S) with phosgene or a carbonic acid diester (e.g., a dialkyl carbonate such as diphenyl carbonate or dimethyl carbonate). These may be used alone or in combination of two or more.

[0036] Examples of polyamide-based resins include homopolymers or copolymers of aliphatic polyamides, aromatic polyamides, and lactams (such as ε-caprolactam). These may be used alone or in combination of two or more. Furthermore, polyamide-based resins are not limited to homopolyamides and may also be copolyamides.

[0037] Examples of polysulfone-based resins include polysulfone, polyethersulfone, etc. These may be used alone or in combination of two or more.

[0038] Examples of polyphenylene resins include polyphenylene oxide resins (homopolymers such as poly(2,5-dimethyl-1,4-phenylene) oxide, poly(2,6-dimethyl-1,4-phenylene) oxide, poly(2-methyl-6-ethyl-1,4-phenylene) oxide, poly(2,6-di-n-propyl-1,4-phenylene) oxide, and poly(2-methyl-6-chloroethyl-1,4-phenylene) oxide; modified polyphenylene oxide copolymers based on polyphenylene oxide blocks; modified graft copolymers in which a styrene polymer is grafted onto polyphenylene oxide or its copolymers); and polyphenylene sulfide resins (polyphenylene sulfide, polyphenylene sulfide ketone, polybiphenylene sulfide, polyphenylene sulfide sulfone, etc.). These may be used alone or in combination of two or more.

[0039] Examples of polyacetal resins include polyacetal (polyoxymethylene) and copolyacetal (e.g., trioxane-ethylene oxide copolymer, trioxane-1,3-dioxolane copolymer, etc.). These may be used alone or in combination of two or more.

[0040] Examples of the thermoplastic elastomer include thermoplastic elastomers composed of a hard phase and a soft phase, such as polyolefin-based thermoplastic elastomers, polystyrene-based thermoplastic elastomers, polyvinyl chloride-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyamide-based thermoplastic resin elastomers, etc. These may be used alone or in combination of two or more.

[0041] Examples of biodegradable resins include one or more selected from cellulose esters, starch polyesters, polylactic acid (PLA), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), polylactic acid / polycaprolactone copolymers, polyglycolic acid (PGA), polylactic acid / polyether copolymers, butanediol / long-chain dicarboxylic acid copolymers, polybutylene adipate / terephthalate (PBAT), polytetramethylene adipate-co-terephthalate, polyethylene terephthalate succinate (PETS), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), and polyvinyl alcohol (PVA).

[0042] Biomass resins are made partially or entirely from bio-derived raw materials, and examples include bio-PE, bio-polyamide 11, bio-polyamide 1010, aromatic polyesters containing bio-derived resins, bio-polyurethane, bio-polycarbonate, bio-MXD10, 1012, 610, 510, 410, 56, 11T, bio-PET, and bio-PTT.

[0043] Among these, the thermoplastic resin (B) preferably contains at least one selected from the group consisting of olefin-based resins and polyamide-based resins. The olefin-based resin may contain bio-PE. The polyamide-based resin may be a petroleum-derived resin or a biomass resin.

[0044] In a preferred embodiment, the olefin resin preferably includes at least one selected from homopolymers or copolymers of olefins having 2 to 6 carbon atoms and copolymers of olefins having 2 to 6 carbon atoms and copolymerizable monomers. More specific examples include polypropylene, high-density polyethylene (HDPE), low-density polyethylene (LDPE), low-density linear polyethylene (LLDPE), poly-1-butene, polyisobutylene, copolymers of ethylene and propylene, ethylene-propylene-diene terpolymers (containing 10% by mass or less of a diene component as a raw material), polymethylpentene, random, block, and / or graft copolymers of ethylene or propylene (50% by mole or more) with other copolymerizable monomers (such as vinyl acetate, (meth)acrylic acid alkyl esters, and aromatic vinyl compounds). It is preferable to use one of these olefin resins alone or two or more of them in combination. Among these, polypropylene is particularly preferred from the viewpoints of mechanical strength and processability.

[0045] In one embodiment, when the thermoplastic resin (B) contains an olefin-based resin and the cellulose fiber (A) contains regenerated cellulose fiber (particularly preferably solvent-process regenerated cellulose), it is preferable to use an acid-modified polyolefin in combination, as this tends to improve the impregnation of the thermoplastic resin (B) into the regenerated cellulose fiber. The acid-modified polyolefin is more preferably a maleic acid-modified polyolefin (preferably a maleic acid-modified polypropylene) or a maleic anhydride-modified polyolefin (preferably a maleic anhydride-modified polyolefin). In one embodiment, when an olefin resin and an acid-modified polyolefin are used in combination as the thermoplastic resin (B), it is more preferable to use the acid-modified polyolefin in combination so that the acid amount in the thermoplastic resin (B) (the amount of acid component contained in the acid-modified polyolefin) is in the range of an average of 0.05 to 0.5 mass% in terms of maleic anhydride.

[0046] In a preferred embodiment, the polyamide-based resin preferably includes at least one selected from aliphatic polyamides and aromatic polyamides. Specific examples include polyamide 6, polyamide 66, polyamide 69, polyamide 610, polyamide 1010, polyamide 612, polyamide 46, polyamide 11, polyamide 12, aromatic polyamides obtained by reacting aromatic dicarboxylic acids with aliphatic diamines (e.g., nylon 6T (hexamethylenediamine and terephthalic acid), nylon 6I (hexamethylenediamine and isophthalic acid), nylon 9T (nonanediamine and terephthalic acid), nylon M5T (methylpentadiamine and terephthalic acid), nylon 10T (decamethylenediamine and terephthalic acid), etc.), and aromatic polyamides obtained by reacting aliphatic dicarboxylic acids with aromatic diamines (e.g., nylon MXD (metaxylylenediamine and adipic acid)). These polyamide-based resins can be used alone or in combination of two or more.

[0047] Of these polyamide resins, aliphatic polyamides such as polyamide 6, polyamide 69, polyamide 610, polyamide 612, polyamide 11, polyamide 12, and polyamide 1010 are preferred from the viewpoint of processing temperature.

[0048] In one embodiment, the ratio of the thermoplastic resin (B) to the total mass of the resin-impregnated fiber bundle (X) is preferably 50 to 90 mass%, more preferably 60 to 90 mass%, and even more preferably 60 to 80 mass%. When the ratio of the thermoplastic resin (B) to the total mass of the resin-impregnated fiber bundle (X) is within the above range, it becomes easy to prepare a resin-impregnated fiber bundle (X) with a high ratio of cellulose fibers (A), and it becomes easy to obtain a small molded product with excellent mechanical strength.

[0049] <Other ingredients (C)> The resin-impregnated fiber bundle (X) according to the first embodiment may contain known additives (other components (C)) within the range that does not impair the effects of the present invention. Examples of other components (C) include flame retardants and flame retardant auxiliaries, heat stabilizers, lubricants, processing stabilizers, light stabilizers, antioxidants, colorants, mold release agents, and antistatic agents. These may be used alone or in combination of two or more. These additives may be contained in the fiber bundle (A1), or in the thermoplastic resin (B) that is the impregnation resin, or may be attached to at least a portion of the surface of the resin-impregnated fiber bundle (X).

[0050] In one embodiment, the cross-sectional shape of the resin-impregnated fiber bundle (X) may be substantially circular or flat. When used as a raw resin for a press-molded product, the cross-sectional shape may be rectangular or triangular (preferably rectangular) from the viewpoint of facilitating filling into a mold without gaps.

[0051] In one embodiment, the length of the major axis in the cross section of the resin-impregnated fiber bundle (X) may be 0.5 to 5 mm, 1 to 4 mm, more than 2.0 mm but not more than 3.0 mm, or 2.3 to 2.8 mm. The length of the minor axis in the cross section may be 0.5 to 5 mm, 1 to 4 mm, more than 2.0 mm but not more than 3.0 mm, or 2.2 to 2.7 mm. The lengths of the major and minor axes in the cross section of the resin-impregnated fiber bundle (X) can be measured using a microscope or a scanning electron microscope.

[0052] The resin-impregnated fiber bundle (X) according to the first embodiment is longer than pellets of a conventional fiber-containing resin composition, and therefore tends to have a higher bulk density than the pellets. Furthermore, because it has a certain length, it is easily shapable when it is arranged parallel to one direction in a mold (for example, the longitudinal or lateral direction of the mold) and press-molded. Furthermore, the press-molded product obtained by this method has improved mechanical strength, particularly in one direction. Furthermore, for example, UD tape (tape of a unidirectional continuous fiber-reinforced material) is stored in a rolled state, and the tape may develop a curl, causing deformation. The resin-impregnated fiber bundle (X) according to the first embodiment can be stored in a bundled state of multiple resin-impregnated fiber bundles (X), and therefore is less likely to deform during storage. Deformation due to curl or other factors can cause problems when arranging the fiber bundle in a desired position or direction in a mold, or can require a large number of steps.

[0053] <Method for producing resin-impregnated fiber bundle (X)> The resin-impregnated fiber bundle (X) according to the first embodiment is a composite material obtained by impregnating a fiber bundle (A1) in which cellulose fibers (A) are aligned in the longitudinal direction with a thermoplastic resin (B), and then cutting the fiber bundle to a length of more than 30 mm and not more than 1000 mm. The resin-impregnated fiber bundle (X) according to the first embodiment can be produced by a known production method using a die. Specifically, the production methods described in JP-A-6-313050, JP-A-2007-176227, JP-B-6-2344, etc. can be applied. By such a method, a strand-shaped resin-impregnated fiber bundle (X) can be produced.

[0054] In a preferred embodiment, the method for producing the resin-impregnated fiber bundle (X) may include impregnating a fiber bundle (A1) formed by bundling preferably 100 to 30,000 regenerated cellulose fibers (A), more preferably 300 to 5,000 regenerated cellulose fibers (A), aligned in the length direction, with a molten thermoplastic resin (B) (preferably an olefin-based resin) to integrate the fiber bundle, and cutting the integrated resin-impregnated fiber bundle to a length of more than 30 mm and not more than 1,000 mm.

[0055] The resin-impregnated fiber bundle (X) according to the first embodiment has a strand-like shape with a length of more than 30 mm and not more than 1000 mm. The present inventors have found that by using such a long resin-impregnated fiber bundle (X) as a raw material resin for molded products, preferably as a raw material resin for press-molded products, and particularly preferably as a raw material resin for small press-molded products, it is possible to produce small molded products having higher mechanical strength and good appearance.

[0056] When pellets of a fiber-reinforced resin composition are press-molded, the pellets are dispersed and filled into a mold, and then pressed to obtain a molded product. This molding method has the advantage of making the filler less likely to break than injection molding, making it easier to obtain high-strength molded products. However, the inventors' studies have revealed that typical press molding techniques result in random filler placement in the molded product, making it difficult for the molded product to exhibit sufficient mechanical strength, particularly in the longitudinal direction. In the case of small molded products, it is difficult for the filler to be filled into the edges and details, and the random filler placement, as described above, further hinders the development of sufficient mechanical strength. Furthermore, the small size of the mold and density limitations of small molded products make it even more difficult to improve mechanical strength. Furthermore, increasing the pellet filling amount can lead to concerns that the filler may protrude from the surface of the molded product, degrading its appearance.

[0057] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by using cellulose fibers (A) as a filler, impregnating a fiber bundle (A1) obtained by aligning the cellulose fibers (A) in the longitudinal direction with a thermoplastic resin (B) to form a resin-impregnated fiber bundle (X), and setting the length of the resin-impregnated fiber bundle (X) to be longer than 30 mm and not longer than 1000 mm. Specifically, since the resin-impregnated fiber bundle (X) having a length longer than 30 mm and not longer than 1000 mm has a high bulk density, for example, by arranging two or more resin-impregnated fiber bundles (X) parallel to one direction of the mold (preferably the longitudinal direction and / or lateral direction of the mold), the gaps between the resin-impregnated fiber bundles (X) can be reduced, allowing for efficient and orderly arrangement in the mold. Furthermore, because the cellulose fibers (A) serving as a filler can be aligned in the mold, press-molded products with high mechanical strength in one direction can be produced. Furthermore, by aligning the filler orientation in one direction, it is possible to prevent the filler from protruding from the surface of the molded product, which would otherwise deteriorate the appearance. Furthermore, such a resin-impregnated fiber bundle (X) also has good formability.

[0058] In one embodiment, the bulk specific gravity of the resin-impregnated fiber bundle (X) having a length of 100 mm may be 0.3 to 1.0, 0.4 to 0.9, or 0.5 to 0.8.

[0059] <Application> As described above, the resin-impregnated fiber bundle (X) according to the first embodiment can be suitably used as a raw resin for press-molded products. In particular, it can be suitably used as a raw resin for small press-molded products. Naturally, the use of the resin-impregnated fiber bundle (X) according to the first embodiment is not limited to press-molded products. The resin-impregnated fiber bundle (X) according to the first embodiment may also be used as a raw resin for injection-molded products.

[0060] [Resin composition] A second embodiment of the present disclosure relates to a resin composition. The resin composition according to the second embodiment contains the resin-impregnated fiber bundle (X) according to the first embodiment.

[0061] The resin composition according to the second embodiment may contain, in addition to the resin-impregnated fiber bundle (X), one or more thermoplastic resins described in the section on thermoplastic resin (B) above. The thermoplastic resin contained in the resin composition may be the same as or different from the thermoplastic resin (B) described above. Furthermore, the resin composition according to the second embodiment may contain other components described above.

[0062] The content of the resin-impregnated fiber bundle (X) in the resin composition can be set arbitrarily within a range that does not impair the effects of the present invention. In one embodiment, the proportion of the resin-impregnated fiber bundle (X) to the total mass of the resin composition may be 3 to 60 mass%.

[0063] [Molded products and their manufacturing methods] A third embodiment of the present disclosure is a molded article of the resin-impregnated fiber bundle (X) according to the first embodiment and a method for producing the same. The molded article according to the third embodiment can be produced by a production method including injection molding or press molding the resin-impregnated fiber bundle (X) according to the first embodiment. In a preferred embodiment, the method for producing a molded article according to the third embodiment may include cutting the resin-impregnated fiber bundle (X) to any length of more than 30 mm and not more than 1000 mm before the injection molding or press molding.

[0064] The conditions for injection molding are not particularly limited, and known conditions can be used. When the molded article according to the third embodiment is produced by injection molding, the length of the resin-impregnated fiber bundle (X) is preferably set within a range that allows the resin-impregnated fiber bundle (X) to be introduced from the hopper of an injection molding machine. In one embodiment, it is preferable to produce a resin-impregnated fiber bundle (X) having a length of more than 30 mm and not more than 50 mm by injection molding. When the resin-impregnated fiber bundle (X) contains an olefin-based resin as the thermoplastic resin (B), the injection molding may be performed under conditions of, for example, a mold temperature of 40 to 120°C and a molding temperature of 180 to 250°C. The conditions for press molding are not particularly limited, and known conditions can be used. In a preferred embodiment, the press-molded product may be manufactured by the method for manufacturing a press-molded product described below.

[0065] When cutting the resin-impregnated fiber bundle (X) to a desired length is included, the method for cutting the resin-impregnated fiber bundle (X) is not particularly limited, and for example, a circular saw cutter or the like may be used. The length of the resin-impregnated fiber bundle (X) can be set arbitrarily depending on the size and physical properties of the molded product. For example, when a small molded product is produced by press molding using the resin-impregnated fiber bundle (X), the resin-impregnated fiber bundle (X) may be cut to the same length as one direction of the mold (preferably the same length as the longitudinal direction and / or the same length as the lateral direction of the mold). By cutting the resin-impregnated fiber bundle (X) to the same length as one direction of the mold and arranging the resin-impregnated fiber bundles (X) of that length parallel to one direction of the mold, good shaping properties are likely to be obtained. Furthermore, small molded products with excellent mechanical strength are likely to be obtained.

[0066] [Press-molded products and their manufacturing methods] A fourth embodiment of the present disclosure relates to a press-formed product and a manufacturing method thereof. In the press-molded product according to the fourth embodiment, cellulose fibers (A) having a length of more than 30 mm and not more than 1000 mm are embedded in a thermoplastic resin (B) in a state where they are arranged parallel to one direction of the press-molded product. In this way, by arranging cellulose fibers (A) having a specific length parallel to one direction of the press-molded product, a molded product with higher mechanical strength is obtained. For example, when the cellulose fibers (A) are arranged parallel to the longitudinal direction of the press-molded product, the molded product has good mechanical strength in the longitudinal direction. Furthermore, the cellulose fibers (A) protrude little from the surface of the molded product, resulting in a good appearance.

[0067] The cellulose fibers (A) contained in the press-molded product may be fiber bundles (A1). That is, the press-molded product may be one in which fiber bundles (A1) of cellulose fibers (A) having a length of more than 30 mm and not more than 1,000 mm are embedded in the thermoplastic resin (B) in a state in which they are arranged parallel to one direction of the press-molded product (preferably the longitudinal direction of the press-molded product). In this case, it is preferable that the thermoplastic resin (B) also fills the gaps between the cellulose fibers (A) in the fiber bundles (A1). Note that the phrase "the press-molded product contains fiber bundles (A1)" includes a state in which a bundle of preferably 100 to 30,000 cellulose fibers (A), more preferably 300 to 15,000 cellulose fibers, and even more preferably 300 to 10,000 cellulose fibers (A) aligned in the longitudinal direction is embedded in the thermoplastic resin (B). Furthermore, the phrase "the press-molded article contains cellulose fibers (A)" refers to a state in which preferably 100 to 30,000, more preferably 300 to 15,000, and even more preferably 300 to 10,000 cellulose fibers (A) are dispersed and embedded in the thermoplastic resin (B). In a preferred embodiment, the press-molded article may contain 100 to 30,000 (more preferably 300 to 10,000) cellulose fibers (A) having a length of more than 30 mm and not more than 1,000 mm, embedded in the thermoplastic resin (B) in a state in which the fibers are arranged parallel to one direction of the press-molded article.

[0068] The cellulose fibers (A) and / or fiber bundles (A1) and the thermoplastic resin (B) contained in the press-molded product can be those described in the first embodiment. In a particularly preferred embodiment, the cellulose fibers (A) may be regenerated cellulose fibers or solvent-process regenerated cellulose fibers. The thermoplastic resin (B) may be an olefin resin or a polypropylene resin.

[0069] The content of the cellulose fibers (A) and / or fiber bundles (A1) in the press-molded product can be set arbitrarily depending on the physical properties required of the press-molded product. In one embodiment, the content of the cellulose fibers (A) and / or fiber bundles (A1) relative to the total mass of the press-molded product may be 10 to 50 mass%, 10 to 40 mass%, or 20 to 40 mass%.

[0070] In one embodiment, the press-molded product may have cellulose fibers (A) having a length of more than 30 mm and not more than 1000 mm embedded in the thermoplastic resin (B) in a state where the fibers are arranged parallel to the longitudinal direction of the press-molded product and parallel to the lateral direction of the press-molded product. In this case, the press-molded product may have a layer in which the cellulose fibers (A) having a length of more than 30 mm and not more than 1000 mm are embedded in the thermoplastic resin (B) in a state where the fibers are arranged parallel to the longitudinal direction of the press-molded product, and a layer in which the cellulose fibers (A) having a length of more than 30 mm and not more than 1000 mm are embedded in the thermoplastic resin (B) in a state where the fibers are arranged parallel to the lateral direction of the press-molded product. That is, the press-molded product may have two or more resin layers in which the orientation of the cellulose fibers (A) is different. Alternatively, in one resin layer, the cellulose fibers (A) having a length of more than 30 mm and not more than 1000 mm may be arranged perpendicular to each other. The most preferred embodiment, which is likely to achieve higher mechanical strength and produce a molded product with a good appearance, is one in which all of the cellulose fibers (A) having a length of more than 30 mm and not more than 1000 mm are embedded in the thermoplastic resin (B) in a state in which they are arranged parallel to one direction of the press-molded product. The direction and proportion of the cellulose fibers (A) in the press-molded product can be observed visually or with a microscope, for example. For example, the direction of the cellulose fibers (A) or fiber bundles (A1) contained in the press-molded product can be confirmed with a microscope, and the proportion can be calculated by counting the number of cellulose fibers (A) or fiber bundles (A1) in the same direction.

[0071] From the viewpoint of easily achieving higher mechanical strength in a specific direction and producing a molded product with a good appearance, it is preferable not to include an embodiment in which the cellulose fibers (A) and / or fiber bundles (A1) having a length of more than 30 mm and not more than 1000 mm are randomly arranged. Here, "the cellulose fibers (A) and / or fiber bundles (A1) are randomly arranged" means that the proportion of the cellulose fibers (A) and / or fiber bundles (A1) that are aligned in one specific direction among all the cellulose fibers (A) and / or fiber bundles (A1) contained in the press-molded product is 10% or less.

[0072] In the press-molded product according to this embodiment, the proportion of the cellulose fibers (A) (and / or fiber bundles (A1)) arranged parallel to one direction of the press-molded product is preferably more than 10% but not more than 100%, more preferably 30 to 100%, even more preferably 50 to 100%, even more preferably 60 to 100%, and particularly preferably 70 to 100% of the total number of cellulose fibers (A) contained in the press-molded product. As described above, when the cellulose fibers (A) and / or fiber bundles (A1) are arranged parallel to the longitudinal direction of the press-molded product and also parallel to the lateral direction, the total of the cellulose fibers (A) arranged in the longitudinal and lateral directions preferably amounts to 100%.

[0073] The thickness of the press-molded product according to the fourth embodiment may be 1.0 to 10 mm. The density of the press-molded product may also be 0.92 to 1.10 g / cm. 3 That is, the press-molded product according to the fourth embodiment may be a small-sized molded product having the thickness and / or density described above.

[0074] The thickness of the press-molded product can be set arbitrarily in the range of 1.0 to 10 mm. In one embodiment, the thickness of the press-molded product may be 1.0 to 8 mm, or may be 1.0 to 6 mm. The thickness of the press-molded product can be measured using a vernier caliper or the like.

[0075] The density of the press-molded product is 0.92 to 1.10 g / cm 3 In one embodiment, the density of the press-molded product is 0.92 g / cm 3 More than 1.10g / cm 3 It may be less than 0.93 to 1.09 g / cm 3 The density of the press-molded product can be measured with a hydrometer.

[0076] The press-molded product may contain components other than the cellulose fibers (A) and the thermoplastic resin (B). Preferred examples of such components include the other components described in the first embodiment. The press-molded product may contain one or more of the other components.

[0077] <Method of manufacturing press-molded products> The press-molded product according to the fourth embodiment can be manufactured by a method for manufacturing a press-molded product, which includes arranging two or more resin-impregnated fiber bundles (X) so that they are parallel to one direction of a mold, and press-molding the resin-impregnated fiber bundles (X).

[0078] The manufacturing method according to the fourth embodiment includes arranging two or more resin-impregnated fiber bundles (X) parallel to one direction of a mold. In a preferred embodiment, the manufacturing method includes arranging two or more resin-impregnated fiber bundles (X) parallel to the longitudinal direction of the mold. The number of resin-impregnated fiber bundles (X) to be arranged is not particularly limited and can be set arbitrarily depending on the size of the mold. In a preferred embodiment, the total volume of the resin-impregnated fiber bundles (X) arranged parallel to one direction of the mold relative to the volume of the mold may be 90 to 120%, or may be 95 to 110%. Here, the total volume is a value calculated from the volume of the molded product (volume of the mold) and the true specific gravity of the resin-impregnated fiber bundles (X) used. The reason why the total volume is 100% or more is that it includes an embodiment in which the resin-impregnated fiber bundles (X) are arranged at a value that is greater than 0% and not more than about 20% higher than the calculated value in order to prevent the thickness of the obtained molded product from becoming small.

[0079] The method for arranging two or more resin-impregnated fiber bundles (X) in parallel to one direction of the mold is not particularly limited, and may be carried out manually or by using an automatic weighing device, for example.

[0080] After placing the resin-impregnated fiber bundle (X) in the mold, it is preferable to preheat the resin-impregnated fiber bundle (X) in the mold with a non-contact heater. The non-contact heater preferably has a heat source of at least one selected from infrared rays, near-infrared rays, induction heating (IH), and hot air. The preheating is preferably carried out until the resin-impregnated fiber bundles (X) placed in the mold are fused together and integrated to the extent that they do not move as a whole. In one embodiment, the preheating temperature may be 160 to 260°C or 180 to 240°C.

[0081] Next, the resin-impregnated fiber bundle (X) is press-molded. The press-molding is performed while heating the resin-impregnated fiber bundle (X). The heating temperature during pressing is preferably lower than the softening temperature of the thermoplastic resin (B) contained in the resin-impregnated fiber bundle (X) and lower than the preheating temperature. In one embodiment, when the thermoplastic resin (B) contains an olefin-based resin, the heating temperature may be 180 to 240°C or 190 to 220°C.

[0082] In the press molding process, a heat-and-cool molding method can be applied to shorten the molding cycle time and improve the surface appearance. The heat-and-cool molding method is a method in which the mold temperature is rapidly raised before press molding, and then the molded product is rapidly cooled. Furthermore, the press-molded molded product may be subjected to the above-mentioned preheating treatment again, and then press-molded again to improve the dispersibility of the cellulose fibers (A) in the molded product.

[0083] The manufacturing method according to the fourth embodiment may include cutting the resin-impregnated fiber bundles (X) to any length longer than 30 mm and not longer than 1000 mm before arranging two or more resin-impregnated fiber bundles (X) parallel to one direction of the mold. The length of the resin-impregnated fiber bundles (X) is preferably the same as the length of one direction of the mold. In a more preferred embodiment, the method includes cutting the resin-impregnated fiber bundles (X) to the same length as the length of the longitudinal or lateral direction of the mold.

[0084] [Application] The press-molded product according to the fourth embodiment is preferably a small-sized molded product. The small-sized molded product according to the fourth embodiment has higher mechanical strength and a good appearance. Furthermore, it is characterized by being superior in mechanical strength in a specific direction. Such press-molded products, particularly small-sized molded products, can be preferably used in various fields where wood is used as a raw material, for example.

[0085] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of the present disclosure are set forth below. [1] A resin-impregnated fiber bundle (X), The resin-impregnated fiber bundle (X) is a fiber bundle (A1) obtained by bundling cellulose fibers (A) aligned in the length direction and impregnating the fiber bundle (A1) with a thermoplastic resin (B), The resin-impregnated fiber bundle (X) has a length of more than 30 mm and not more than 1000 mm. [2] The resin-impregnated fiber bundle (X) according to [1], wherein the cellulose fibers (A) are regenerated cellulose fibers. [3] The resin-impregnated fiber bundle (X) according to [1] or [2], wherein the cellulose fibers (A) have an average fiber diameter of 5 to 30 μm. [4] The resin-impregnated fiber bundle (X) according to any one of [1] to [3], wherein the fiber bundle (A1) contains 100 to 30,000 of the cellulose fibers (A). [5] The resin-impregnated fiber bundle (X) according to any one of [1] to [4], wherein the degree of X-ray orientation of the cellulose fibers (A) is 90% or more. [6] The resin-impregnated fiber bundle (X) according to any one of [1] to [5], which is for use in press-molded products. [7] A resin composition comprising the resin-impregnated fiber bundle (X) according to any one of [1] to [6]. [8] A molded product of the resin-impregnated fiber bundle (X) according to any one of [1] to [6]. [9] A method for producing a molded article according to [8], A method for producing a molded product, comprising injection molding or press molding the resin-impregnated fiber bundle (X).

[10] A method for producing a molded product according to [9], which comprises cutting the resin-impregnated fiber bundle (X) to any length in the range of more than 30 mm and not more than 1000 mm before the injection molding or press molding.

[11] A press-molded product, The press-molded product is a press-molded product in which cellulose fibers (A) having a length of more than 30 mm and not more than 1000 mm are embedded in a thermoplastic resin (B) in a state where the fibers are arranged parallel to one direction of the press-molded product.

[12] The press-molded product has a thickness of 1.0 to 10 mm and a density of 0.92 to 1.10 g / cm 3 The press-molded product according to

[11] ,

[13] A method for producing a press-molded product according to

[11] or

[12] , Arranging two or more resin-impregnated fiber bundles (X) according to any one of [1] to [6] so that they are parallel to one direction of the mold; and A method for producing a press-molded product, comprising press-molding the resin-impregnated fiber bundle (X).

[14] The method for producing a press-molded product according to

[13] , which includes cutting the resin-impregnated fiber bundle (X) to any length in the range of more than 30 mm and not more than 1000 mm before the arranging. [Example]

[0086] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following description.

[0087] The details of the components and molding method shown in Table 1 are as follows. <Cellulose fiber (A)> Solvent-process regenerated cellulose fiber: Lyocell fiber, average fiber diameter 11 μm, X-ray orientation degree 93%. <Thermoplastic resin (B)> (B1): Polypropylene: Manufactured by SunAllomer Co., Ltd., product name "PMB02A". (B2): Maleic anhydride modified polypropylene resin: manufactured by SK Functional Polymer, product name "OREVAC (registered trademark) CA100". <Other ingredients (C)> (C1): Hindered phenol-based antioxidant: BASF Japan Ltd., product name "Irganox (registered trademark) 1010FF". (C2): Hindered amine light stabilizer: manufactured by BASF Japan Ltd., product name "Tinuvin (registered trademark) 111 FDL". (C3): Phosphorus-based processing stabilizer: BASF Japan Ltd., product name "Irgafos (registered trademark) 168".

[0088] <Forming method> Drying conditions: For molding methods 1 to 3, the resin-impregnated fiber bundle (X) was dried at 120°C for 3 hours before molding. Forming method 1: An aluminum mold (a 200 mm × 200 mm square aluminum plate with a thickness of 2 mm and a rectangular hole with a width of 20 mm and a length of 100 mm in the center) was placed on top of iron plate 1 (a 300 mm × 300 mm square iron plate with a thickness of 3 mm). Then, 12 100 mm long resin-impregnated fiber bundles (X) (weighing approximately 0.35 g) were placed in the hole. The resin-impregnated fiber bundles (X) were arranged parallel to the longitudinal direction. This was placed on the lower heating platen of a press set to 200°C. Iron plate 2 (a 300 mm × 300 mm iron plate with a thickness of 3 mm) was then placed on top of it. The lower heating platen of the press was raised until it lightly touched the upper heating platen of the press. After leaving it in this state for 1 minute, the lower heating platen was raised by several centimeters and left for an additional 2 minutes. The lower heating platen was then raised until the press load reached 4 tons, and the press was left standing for another 1 minute and 30 seconds. The lower heating platen was then lowered, and the aluminum mold plate sandwiched between the two iron plates 1 and 2 was quickly removed. It was then placed on a cooling press (heating platen temperature: room temperature) and cooled for 3 minutes under a load of 3 tons. The molded test piece was then removed. Forming method 2: An aluminum mold (a 300 mm × 300 mm square aluminum plate with a thickness of 2 mm, with a 20 mm wide × 250 mm long rectangular hole in the center diagonally across the aluminum plate) was placed on top of iron plate 1 (a 300 mm × 300 mm square iron plate with a thickness of 3 mm). Then, 12 250 mm long resin-impregnated fiber bundles (X) (weighing approximately 0.87 g) were placed in the hole. The resin-impregnated fiber bundles (X) were arranged parallel to the longitudinal direction. This was placed on the lower heating plate of a press set to 200°C. Iron plate 2 (a 300 mm × 300 mm thick iron plate) was then placed on top of it. The lower heating plate of the press was raised until it lightly touched the upper heating plate of the press. After leaving this state for 1 minute, the lower heating plate was raised by several centimeters and left for an additional 2 minutes. The lower heating platen was then raised until the press load reached 4 tons, and the press was left standing for another 1 minute and 30 seconds. The lower heating platen was then lowered, and the aluminum mold plate sandwiched between the two iron plates 1 and 2 was quickly removed. It was then placed on a cooling press (heating platen temperature: room temperature) and cooled for 3 minutes under a load of 3 tons. The molded test piece was then removed. Molding method 3: Press molding was performed in the same manner as molding method 1, except that 4.17 g of resin-impregnated fiber bundles with a length of 7 mm were randomly arranged. Molding method 4: Resin-impregnated fiber bundles were injection molded under the following conditions. (Injection molding conditions) Molding machine: Shibaura Machine Co., Ltd., product name "EC40". Test piece: dumbbell-shaped test piece (thickness 2 mm) Molding temperature: 200℃. Mold temperature: 60℃.

[0089] [Example 1] Thermoplastic resins (B1) and (B2) and other components (C1) to (C3) were fed into a twin-screw extruder and melt-kneaded at a cylinder temperature of 260°C. A fiber bundle of 5,400 cellulose fibers (A) aligned in the longitudinal direction was passed through a crosshead die. The fiber bundle was impregnated with 30% by mass of cellulose fiber (A) and 70% by mass of thermoplastic resins (B1) to (B2) and other components (C1) to (C3). The fiber bundle was then shaped using a shaping nozzle at the crosshead die outlet, shaped using a shaping roll, and cut into 100 mm lengths using a pelletizer to obtain a strand-like resin-impregnated fiber bundle (X1). The resin-impregnated fiber bundle (X1) obtained in Example 1 was press-molded using molding method 1 to obtain a molded product (test piece). That is, the resin-impregnated fiber bundles (X1) were arranged parallel to the longitudinal direction of a mold (a hole in an aluminum mold plate (width 20 mm × length 100 mm × thickness 2 mm)). The proportion of the resin-impregnated fiber bundles (X1) arranged parallel to the longitudinal direction was 100%. Thereafter, press molding was performed under the conditions described in the molding method 1 to obtain a molded product (test piece). The density of the obtained molded product was 1.02 g / cm 3 The flexural modulus of the obtained test specimen was measured under the following conditions. The appearance of the molded product was also evaluated under the following conditions. The results are shown in Table 1.

[0090] [Example 2] Thermoplastic resins (B1) and (B2) and other components (C1) to (C3) were fed into a twin-screw extruder and melt-kneaded at a cylinder temperature of 260°C. A fiber bundle of 5,400 cellulose fibers (A) aligned longitudinally was passed through a crosshead die. The fiber bundle was impregnated with 30% cellulose fiber (A) by mass and 70% thermoplastic resins (B1) to (B2) and other components (C1) to (C3) by mass. The fiber bundle was then shaped using a shaping nozzle at the crosshead die outlet, trimmed with a shaping roll, and cut to 1000 mm lengths with nippers to obtain a resin-impregnated fiber bundle (X2). The 1000 mm resin-impregnated fiber bundle (X2) was further cut to 100 mm lengths with a circular saw to obtain a resin-impregnated fiber bundle (X2-100). The resin-impregnated fiber bundle (X2-100) obtained in Example 2 was press-molded by molding method 1 to obtain a molded product (test piece). That is, the resin-impregnated fiber bundle (X2-100) was arranged parallel to the longitudinal direction of a mold (a hole (width 20 mm × length 100 mm × thickness 2 mm) of an aluminum mold plate). The proportion of the resin-impregnated fiber bundle (X2-100) arranged parallel to the longitudinal direction was 100%. Thereafter, press molding was performed under the conditions described in molding method 1 to obtain a molded product (test piece). The density of the obtained molded product was 1.02 g / cm 3 The flexural modulus of the obtained test specimen was measured under the following conditions. The appearance of the molded product was also evaluated under the following conditions. The results are shown in Table 1.

[0091] [Example 3] The 1000 mm strand-shaped resin-impregnated fiber bundle (X2) obtained in Example 2 was further cut into 250 mm pieces using a circular saw to obtain a strand-shaped resin-impregnated fiber bundle (X2-250). The obtained strand-shaped resin-impregnated fiber bundle (X2-250) of Example 3 was press-molded using molding method 2 to obtain a molded product. That is, the resin-impregnated fiber bundle (X2-250) was arranged so as to be parallel to the longitudinal direction of a mold (a hole in an aluminum mold plate (width 20 mm × length 250 mm × thickness 2 mm)). The proportion of the resin-impregnated fiber bundle (X2-250) arranged parallel to the longitudinal direction was 100%. Thereafter, press molding was performed under the conditions described in molding method 2 to obtain a molded product. The density of the obtained molded product was 1.02 g / cm 3 In order to evaluate the variation in the flexural modulus depending on the location of the obtained molded product, test pieces were prepared by cutting the product at 80 mm, 80 mm, and 90 mm from the edge, and the flexural modulus of each test piece was measured under the following conditions.

[0092] <Method for measuring flexural modulus> The test specimens obtained in each example were used to measure the flexural modulus in accordance with ISO 178. Specifically, the flexural modulus of the test specimens was measured using a bending tester (manufactured by Toyo Seiki Seisakusho, product name "Bendograph II") under conditions of a temperature of 23°C, a test speed of 1 mm / min, and a span distance of 32 mm. In Example 3, the flexural modulus was measured at two locations on the ends of the test specimen and at the center. The results are shown in Table 1.

[0093] <Appearance evaluation of molded products> The appearance of the obtained molded article was visually inspected, and molded articles in which there was no filler protruding from the surface were evaluated as passing, and molded articles in which there was filler protruding from the surface or in which the filler caused unevenness on the surface were evaluated as failing.

[0094] [Comparative Examples 1 to 2] Thermoplastic resins (B1) and (B2) and other components (C1) to (C3) were fed into a twin-screw extruder and melt-kneaded at a cylinder temperature of 260°C. A fiber bundle of 5,400 cellulose fibers (A) aligned in the longitudinal direction was passed through a crosshead die and impregnated with 30% by mass of cellulose fiber (A) and 70% by mass of thermoplastic resins (B1) and (B2) and other components (C1) to (C3). The fiber bundle was then shaped using a shaping nozzle at the exit of the crosshead die, shaped using a shaping roll, and cut into 7 mm lengths using a pelletizer to obtain a resin-impregnated fiber bundle in the form of pellets. In Comparative Example 1, the obtained resin-impregnated fiber bundle was press-molded using molding method 3 to obtain a molded product (test piece). The density of the obtained molded product was 1.02 g / cm. 3 The flexural modulus of the obtained test piece was measured under the same conditions as in Example 1. The results are shown in Table 1. In Comparative Example 2, the resin-impregnated fiber bundle obtained above was injection molded by molding method 4 to obtain a molded product (test piece). The density of the obtained molded product was 1.02 g / cm 3 The flexural modulus of the obtained test piece was measured under the same conditions as in Example 1. The results are shown in Table 1.

[0095] [Table 1]

[0096] As shown in Table 1, the press-molded products of Examples 1 to 3 obtained by arranging the resin-impregnated fiber bundle (X) according to the first embodiment so as to be parallel to the longitudinal direction of the mold and then press-molding had higher mechanical strength than the press-molded product of Comparative Example 1 and the injection-molded product of Comparative Example 2. The appearance of the molded products was also good. From the above results, it was confirmed that the resin-impregnated fiber bundle (X) according to the first embodiment can be used to manufacture small molded products having higher mechanical strength and good appearance. It was also confirmed that the press-molded product according to the fourth embodiment and its manufacturing method can provide press-molded products having higher mechanical strength and good appearance.

Claims

1. A resin-impregnated fiber bundle (X), The resin-impregnated fiber bundle (X) is a fiber bundle (A1) obtained by bundling cellulose fibers (A) aligned in the length direction, and impregnated with a thermoplastic resin (B), The resin-impregnated fiber bundle (X) has a length of more than 30 mm and not more than 1000 mm.

2. The resin-impregnated fiber bundle (X) according to claim 1, wherein the cellulose fibers (A) are regenerated cellulose fibers.

3. The resin-impregnated fiber bundle (X) according to claim 1 or 2, wherein the cellulose fibers (A) have an average fiber diameter of 5 to 30 μm.

4. The resin-impregnated fiber bundle (X) according to claim 1 or 2, wherein the fiber bundle (A1) contains 100 to 30,000 of the cellulose fibers (A).

5. The resin-impregnated fiber bundle (X) according to claim 1 or 2, wherein the cellulose fibers (A) have an X-ray orientation degree of 90% or more.

6. The resin-impregnated fiber bundle (X) according to claim 1 or 2, which is for use in press-molded products.

7. A resin composition comprising the resin-impregnated fiber bundle (X) according to claim 1 or 2.

8. A molded product of the resin-impregnated fiber bundle (X) according to claim 1 or 2.

9. A method for producing a molded product according to claim 8, A method for producing a molded article, comprising injection molding or press molding the resin-impregnated fiber bundle (X).

10. The method for producing a molded product according to claim 9, further comprising cutting the resin-impregnated fiber bundle (X) to an arbitrary length in the range of more than 30 mm and not more than 1000 mm before the injection molding or press molding.

11. A press-molded product, The press-molded product is a press-molded product in which cellulose fibers (A) having a length of more than 30 mm and not more than 1000 mm are embedded in a thermoplastic resin (B) in a state where the cellulose fibers (A) are arranged parallel to one direction of the press-molded product.

12. The press-molded product has a thickness of 1.0 to 10 mm and a density of 0.92 to 1.10 g / cm ３ The press-molded product according to claim 11,

13. The method for manufacturing a press-molded product according to claim 11, Two or more resin-impregnated fiber bundles (X) according to claim 1 are arranged in parallel to one direction of the mold; and A method for producing a press-molded product, comprising press-molding the resin-impregnated fiber bundle (X).

14. The method for producing a press-molded product according to claim 13, further comprising cutting the resin-impregnated fiber bundle (X) to an arbitrary length in a range of more than 30 mm and not more than 1000 mm before the arranging.

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