Resin composition, method for manufacturing the same, pellets, and molded articles

Abstract

The present invention provides a resin composition containing polyamide resin and regenerated cellulose fibers that yields molded articles with superior mechanical properties, a method for producing the same, pellets containing the resin composition, and molded articles. [Solution] A resin composition comprising, with respect to the total mass of the resin composition, 40 to 97% by mass of a thermoplastic resin (A) containing a polyamide resin (a1), 3 to 60% by mass of regenerated cellulose fibers (B), and 0.01% by mass or more of one or more additives (C) selected from maleic anhydride copolymer, blocked polyisocyanate resin, epoxy resin, epoxysilane compound, isocyanatesilane compound, and polyamide epichlorohydrin resin (provided that the sum of (A) to (C) does not exceed 100% by mass).

Description

Technical Field

[0001] The present invention relates to a resin composition, a method for producing the same, pellets, and a molded article.

Background Art

[0002] Toward the construction of a sustainable society, composite resin materials prepared by blending a biomass component into a petroleum-derived resin component have been increasingly utilized. As such a composite resin material, for example, a regenerated cellulose fiber-containing resin composition obtained by filling a thermoplastic resin with regenerated cellulose fibers is known (see, for example, Patent Documents 1 and 2). A molded article that is lightweight and excellent in mechanical properties can be obtained from such a regenerated cellulose fiber-containing resin composition.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, polyamide resins are utilized in various industrial fields by taking advantage of their characteristics of being excellent in mechanical properties and heat resistance. It is expected that by combining such a polyamide resin with regenerated cellulose fibers, a molded article having more excellent mechanical properties can be obtained. However, studies by the inventors of the present application have revealed that it is difficult to obtain desired mechanical properties with a formulation that simply combines a polyamide resin and regenerated cellulose fibers.

[0005] An object of the present disclosure is to provide a resin composition that can provide a molded article more excellent in mechanical properties in a resin composition containing a polyamide resin and regenerated cellulose fibers, a method for producing the same, pellets containing the resin composition, and a molded article. [Means for solving the problem]

[0006] As a result of diligent research, the inventors of the present invention have found that the above-mentioned problems can be solved if the resin composition comprises, with respect to the total mass of the resin composition, 40 to 97% by mass of a thermoplastic resin (A) containing a polyamide resin (a1), 3 to 60% by mass of regenerated cellulose fibers (B), and 0.01% by mass or more of one or more additives (C) selected from maleic anhydride copolymer, blocked polyisocyanate resin, epoxy resin, epoxysilane compound, isocyanatesilane compound, and polyamide epichlorohydrin resin (provided that the sum of (A) to (C) does not exceed 100% by mass). [Effects of the Invention]

[0007] According to this disclosure, a resin composition comprising a polyamide resin and regenerated cellulose fibers can be used to obtain molded articles with superior mechanical properties, a method for producing the same, pellets containing the resin composition, and molded articles can be provided. [Modes for carrying out the invention]

[0008] The following describes in detail one embodiment of this disclosure, but the scope of this disclosure is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of this disclosure. Furthermore, if multiple numerical ranges are described for a particular parameter, any of the numerical values ​​described therein can be combined to create a suitable numerical range. Also, the lower and / or upper limits of the numerical ranges described in this disclosure may be replaced with numerical values ​​within that range, as shown in the examples. The expression "X~Y" indicating a numerical range means "X or more and Y or less". If a particular description given for one embodiment also applies to other embodiments, that description may be omitted in the other embodiments.

[0009] [Resin composition] The first embodiment of this disclosure relates to a resin composition. The resin composition according to the first embodiment comprises, with respect to the total mass of the resin composition, 40 to 97% by mass of a thermoplastic resin (A) containing a polyamide resin (a1), 3 to 60% by mass of regenerated cellulose fibers (B), and 0.01% by mass or more of one or more additives (C) selected from maleic anhydride copolymer, blocked polyisocyanate resin, epoxy resin, epoxysilane compound, isocyanatesilane compound, and polyamide epichlorohydrin resin (provided that the sum of (A) to (C) does not exceed 100% by mass). According to the resin composition according to the first embodiment, a molded article with superior mechanical properties can be provided.

[0010] <Thermoplastic resin (A)> The resin composition according to the first embodiment includes a thermoplastic resin (A) containing a polyamide resin (a1). By combining the thermoplastic resin (A) containing the polyamide resin (a1) (hereinafter referred to as "resin (A)") with regenerated cellulose fibers (B) and additives (C) described later, a molded article with superior mechanical properties can be obtained.

[0011] The proportion of resin (A) in the resin composition according to the first embodiment is 40 to 97% by mass, preferably 45 to 95% by mass, and more preferably 50 to 90% by mass, based on the total mass of the resin composition.

[0012] (Polyamide resin (a1)) Resin (A) contains polyamide resin (a1) (hereinafter referred to as "resin (a1)"). Preferably, resin (A) contains resin (a1) as a main component. Here, "contained as a main component" means that the ratio of resin (a1) to the total mass of resin (A) is greater than 50% by mass and 100% by mass or less. The ratio of resin (a1) to the total mass of resin (A) is more preferably 70 to 100% by mass, and even more preferably 90 to 100% by mass. In one embodiment, resin (A) may contain only resin (a1).

[0013] Resin (a1) is a thermoplastic resin having amide bonds (-NH-C(=O)-) in the polymer main chain. Resin (a1) may be an aliphatic polyamide resin containing only an aliphatic skeleton, a semi-aromatic polyamide resin containing both an aromatic and an aliphatic skeleton, or an aromatic polyamide resin containing only an aromatic skeleton.

[0014] From the viewpoint of easily suppressing thermal degradation of the regenerated cellulose fibers (B) during the preparation of the resin composition, the melting point of the resin (a1) is preferably 100 to 280°C, more preferably 130 to 270°C, and even more preferably 150 to 240°C. The melting point of the resin (a1) can be measured using differential scanning calorimetry (DSC) in accordance with ISO 11357.

[0015] The resin (a1) preferably contains one or more selected from polyamide resins (a11) having repeating units represented by the following formula (I), polyamide resins (a12) having repeating units represented by the following formula (II), and polyamide resins (a13) having repeating units represented by the following formula (III). [ka] (In equation (I), m1 represents a number between 3 and 11, and n1 represents a number greater than or equal to 10.) [ka] (In equation (II), m2 represents a number between 4 and 10, m3 represents a number between 4 and 10, and n2 represents a number greater than or equal to 10.) [ka] (In equation (III), m4 and m5 represent numbers from 1 to 3, m6 represents numbers from 4 to 18, and n3 represents numbers greater than or equal to 10.)

[0016] Among the resins (a11) to (a13) represented by the above formulas (I) to (III), the resin (a11) and the resin (a12) are aliphatic polyamide resins. Further, the resin (a13) is a semi-aromatic polyamide resin. As the resins (a11) to (a13), it is more preferable to use those having a melting point of 100 to 280°C measured under the aforementioned conditions. Further, the melting point may be 130 to 270°C, or may be 150 to 240°C.

[0017] In one embodiment, as the resins (a11) to (a13), those having a melt flow rate (190°C, 2.16 kg load) of 1 to 300 g / 10min may be employed. The melt flow rate may be 20 to 280 g / 10min, or may be 70 to 250 g / 10min. When the melt flow rate (190°C, 2.16 kg load) is within the above range, it becomes easy to achieve both good mechanical properties and moldability. The measurement of the melt flow rate can be performed using a melt flow rate tester (for example, product name "Melt Indexer Model L220" manufactured by Tateyama Science High-Technologies Corporation).

[0018] Preferable examples of the resin (a11) include polyamide 6 in which m1 in formula (I) is 5, polyamide 11 in which m1 is 10, and polyamide 12 in which m1 is 11. In these resins (a11), n1 is preferably 10 to 1000, more preferably 50 to 500. Further, the resin (a11) may be used alone, or two or more kinds may be used in combination.

[0019] Preferable examples of the resin (a12) include polyamide 66 in which m2 is 6 and m3 is 4 in formula (II), and polyamide 610 in which m2 is 6 and m3 is 8. In these resins (a12), n2 is preferably 10 to 1000, more preferably 50 to 500. The resin (a12) may be used alone, or two or more kinds may be used in combination.

[0020] Preferred examples of resin (a13) include polyamide MXD6, in which m4 is 1, m5 is 1, and m6 is 4 in formula (III), and polyamide XD10, in which m4 is 1, m5 is 1, and m6 is 8. In these resins (a13), n3 is preferably 10 to 1000, and more preferably 50 to 500. Resin (a13) may be used alone or in combination of two or more types.

[0021] In one embodiment, the resin (a1) preferably contains resin (a11), and more preferably contains polyamide 12. Polyamide 12 has advantages over other polyamide resins, such as low specific gravity, high toughness, and high dimensional stability, and is used in a wide range of applications. For example, composite materials combining polyamide 12 and carbon fiber are used in shoe soles and bicycle parts due to their high toughness and dimensional stability. However, glass fiber and carbon fiber have the problem of high CO2 emissions during manufacturing. Therefore, if good mechanical properties can be achieved using regenerated cellulose fiber, which has low CO2 emissions during manufacturing, it is thought that it will be possible to develop products with a lower environmental impact. From these viewpoints, it is preferable to include polyamide 12 as the resin (a1).

[0022] When the resin (a1) contains polyamide 12, it is preferable that the amount of polyamide 12 is greater than 50% by mass and 100% by mass or less, more preferably 75 to 100% by mass, and particularly preferably 100% by mass, relative to the total mass of the resin (a1). Furthermore, from the viewpoint of easily achieving both good mechanical properties and moldability, the polyamide 12 is preferably one with a melt flow rate (190°C, 2.16 kg load) of 1 to 300 g / 10 min, more preferably 20 to 280 g / 10 min, and even more preferably 70 to 250 g / 10 min.

[0023] (Other thermoplastic resins (a2)) In one embodiment, resin (A) may include a thermoplastic resin other than resin (a1) (another thermoplastic resin (a2), hereinafter sometimes referred to as "resin (a2)"). As resin (a2), any thermoplastic resin can be selected within the limits that do not impede the effects of this disclosure. For example, olefin resins (polyethylene resins, polypropylene resins, etc.), vinyl alcohol resins, vinyl ester resins, styrene resins, (meth)acrylate resins, polyester resins, polycarbonate resins, polysulfone resins, polyphenylene resins, polyacetal resins, thermoplastic elastomers, etc. can be used. Biodegradable resins and biomass resins can also be used. When resin (A) contains resin (a2), from the viewpoint of the mechanical properties of the molded product, it is preferable that the amount of resin (a2) is 10% by mass or less, and more preferably 5% by mass or less, relative to the total mass of resin (A).

[0024] <Regenerated cellulose fiber (B)> The resin composition according to the first embodiment contains regenerated cellulose fibers (B). The proportion of regenerated cellulose fibers (B) in the resin composition according to the first embodiment is 3 to 60% by mass, preferably 5 to 55% by mass, and more preferably 10 to 50% by mass. In this disclosure, "regenerated cellulose fiber" refers to cellulose fiber that has been artificially spun using natural cellulose fibers (plant-derived cellulose fibers, animal-derived cellulose fibers (such as sea squirt cellulose), or bacterial-derived cellulose fibers).

[0025] Methods for obtaining regenerated cellulose fibers from natural cellulose fibers include, for example, the viscose method, the copper ammonia method, and the solvent spinning method (a method of directly spinning cellulose without first chemically converting it; hereinafter referred to as the "solvent method"). Examples of regenerated cellulose fibers obtained by the viscose method include viscose rayon, polynosic, and modal. Examples of regenerated cellulose fibers obtained by the copper ammonia method include cupro. Furthermore, examples of regenerated cellulose fibers obtained by the solvent method include lyocell and regenerated cellulose fibers obtained by the ionic liquid method. For regenerated cellulose fiber (B), one type of regenerated cellulose fiber obtained by these methods may be used alone, or two or more types may be used in combination. Alternatively, spun fibers obtained by twisting short regenerated cellulose fibers together into a long thread may be used. In one embodiment, the regenerated cellulose fiber (B) may include one or more selected from viscose-processed regenerated cellulose fibers, copper ammonia-processed regenerated cellulose fibers, and solvent-processed regenerated cellulose fibers.

[0026] From the viewpoint of easily suppressing discoloration of molded products, it is preferable to include solvent-processed regenerated cellulose fibers as regenerated cellulose fibers (B). As solvent-processed regenerated cellulose fibers, the aforementioned lyocell, regenerated cellulose fibers obtained by the ionic liquid method, etc., may be used individually or in combination of two or more types.

[0027] • Average fiber length In one embodiment, the average fiber length of the regenerated cellulose fibers (B) in the resin composition is preferably 100 μm or more. Including regenerated cellulose fibers (B) with an average fiber length of 100 μm or more in the resin composition makes it easier to obtain molded articles with superior mechanical properties. From the viewpoint of manufacturability, the upper limit of the average fiber length of the regenerated cellulose fibers (B) in the resin composition is preferably 5,000 μm or less. In one embodiment, the average fiber length of the regenerated cellulose fibers (B) in the resin composition is preferably 100 to 5,000 μm, more preferably 120 to 1,500 μm, and even more preferably 150 to 500 μm. It should be noted that "the average fiber length of the regenerated cellulose fibers (B) in the resin composition is 100 μm or more" can be easily achieved by incorporating raw material regenerated cellulose fibers (B) with an average fiber length of 1 mm or more into the resin composition.

[0028] The average fiber length of the regenerated cellulose fibers (B) in the resin composition can be calculated as the average value of the fiber lengths (length of a single fiber) measured by dissolving and removing the resin components in the resin composition with an organic solvent (such as xylene), dispersing the regenerated cellulose fibers (B) in a medium, and then image processing the fibers (B). Alternatively, if the resin composition is a thermoplastic resin-impregnated regenerated cellulose fiber bundle (B-1) described later, the average fiber length can be calculated by measuring the length of the long axis of approximately 100 pellets of the fiber bundle (B-1) using a caliper or the like, and taking the average value.

[0029] • Average fiber diameter In one embodiment, the average fiber diameter of the regenerated cellulose fibers (B) is preferably 5 to 30 μm, and the X-ray orientation is preferably 86% or higher. Having such an average fiber diameter and X-ray orientation makes it easier for the resin (A) to impregnate the regenerated cellulose fibers (B) when preparing the thermoplastic resin-impregnated regenerated cellulose fiber bundle (B-1) described later. It also makes it easier to improve the mechanical strength of the resulting molded product. The average fiber diameter is more preferably 6 to 20 μm, even more preferably 7 to 15 μm, and most preferably 10 to 14 μm. The average fiber diameter of the regenerated cellulose fiber (B) can be calculated from the average value obtained by observing the diameter (longest axis) of multiple fibers using SEM or the like. Furthermore, it is more preferable that the X-ray orientation degree is 90% or higher. The X-ray orientation degree of the regenerated cellulose fiber (B) can be determined from the formulas described in Japanese Patent Publication No. 9-31744 and Japanese Patent Publication No. 9-256216.

[0030] (Thermoplastic resin-impregnated regenerated cellulose fiber bundle (B-1)) The resin composition according to the first embodiment preferably contains a thermoplastic resin-impregnated regenerated cellulose fiber bundle (B-1) (hereinafter referred to as "fiber bundle (B-1)"), in which a fiber bundle of regenerated cellulose fibers (B) aligned in the length direction is impregnated with a resin (A) containing an additive (C) described later. The method for preparing the fiber bundle (B-1) will be described later, but the additive (C) contained in the fiber bundle (B-1) may be contained in the resin (A) or attached to the regenerated cellulose fibers (B). In either case, the additive (C) is contained in the impregnating resin (A), so in the description of the fiber bundle (B-1), it will be described as "a fiber bundle (B-1) impregnated with resin (A) containing additive (C)". By including the fiber bundle (B-1) in the resin composition according to the first embodiment, a molded article with superior mechanical properties can be obtained. In one embodiment, the resin composition may contain the fiber bundle (B-1) and any thermoplastic resin (for example, the aforementioned resin (a2)), or it may contain only the fiber bundle (B-1).

[0031] Resin compositions containing fiber bundles (B-1) make it easier to obtain molded articles with superior mechanical properties. One particularly preferred embodiment is a fiber bundle (B-1) in which solvent-regenerated cellulose fibers are bundled together aligned in the length direction and impregnated with a resin (a1) containing an additive (C) described later.

[0032] The resin (A) contained in the fiber bundle (B-1) can be exemplified in the same manner as the above-mentioned resin (A), and the preferred examples are also the same. That is, the proportion of resin (a1) in resin (A) is preferably more than 50% by mass and 100% by mass or less, more preferably 70 to 100% by mass, and even more preferably 90 to 100% by mass. The proportion of resin (a1) in the impregnating resin (A) may be 100% by mass.

[0033] Furthermore, the proportions of resin (A), regenerated cellulose fibers (B), and additives (C) described later in the fiber bundle (B-1) can be within the same range as the proportions of each component in the resin composition. That is, relative to the total mass of the fiber bundle (B-1), the proportions can be 40-97% by mass of resin (A), 3-60% by mass of regenerated cellulose fibers (B), and 0.01% by mass or more of one or more additives (C) selected from maleic anhydride copolymer, blocked polyisocyanate resin, epoxy resin, epoxysilane compound, isocyanatesilane compound, and polyamide epichlorohydrin resin (provided that the sum of (A) to (C) does not exceed 100% by mass). The proportions of each component in the fiber bundle (B-1) can be set within the above range or within the range described later, to any preferred range, the same as that of the resin composition.

[0034] The number of regenerated cellulose fibers (B) in the fiber bundle (B-1) is preferably adjusted to a range of 100 to 30,000. In one embodiment, the number of regenerated cellulose fibers (B) is preferably 2,000 to 30,000, more preferably 3,000 to 25,000, and even more preferably 5,000 to 25,000.

[0035] (Method for producing thermoplastic resin-impregnated regenerated cellulose fiber bundles (B-1)) In one embodiment, the fiber bundle (B-1) can be manufactured by a well-known manufacturing method using a die. Specifically, the manufacturing methods described in Japanese Patent Publication No. 6-313050, Japanese Patent Publication No. 2007-176227, Japanese Patent Publication No. 6-2344, etc., can be applied. Details of the manufacturing method of the resin composition, including the preparation of the fiber bundle (B-1), will be described later.

[0036] <Additive (C)> The resin composition according to the first embodiment is characterized by comprising the above-mentioned resin (A) and regenerated cellulose fibers (B), and one or more additives (C) selected from maleic anhydride copolymer, blocked polyisocyanate resin, epoxy resin, epoxysilane compound, isocyanatesilane compound, and polyamide epichlorohydrin resin. The inventors of the present invention have found that by adding a specific amount of additive (C) to the resin (a1) and regenerated cellulose fibers (B), a molded article with improved mechanical properties can be obtained compared to a formulation without additive (C), although the exact reason is unclear.

[0037] Additive (C) is one or more resin components selected from maleic anhydride copolymers, block polyisocyanate resins, epoxy resins, epoxysilane compounds, isocyanatesilane compounds, and polyamide epichlorohydrin resins.

[0038] (Maleic anhydride copolymer) Maleic anhydride copolymers are copolymers of maleic anhydride and monomers having functional groups copolymerizable with maleic anhydride (hereinafter referred to as "other monomers"). Examples of other monomers include (meth)acrylic acid or its derivatives; unsaturated dicarboxylic acid monomers; glycidyl group-containing monomers such as allyl glycidyl ether; silyl group-containing monomers such as vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane and its hydrochloride salts; oxazoline group-containing monomers such as 2-isopropenyl-2-oxazoline and 2-vinyl-2-oxazoline; carbonyl group-containing monomers such as acrolein; vinyl sulfonic acid, Examples include vinyl sulfonic acid monomers such as styrene sulfonic acid; vinyl ester monomers such as vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl versatate; vinyl ether monomers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, amyl vinyl ether, and hexyl vinyl ether; aromatic vinyl compound monomers such as styrene, α-methylstyrene, vinyltoluene, vinylanisole, α-halostyrene, vinylnaphthalene, and divinylstyrene; diene monomers such as isoprene, chloroprene, and butadiene; olefin monomers such as ethylene, propylene, and butene; tetrafluoroethylene; vinylidene fluoride; and N-vinylpyrrolidone. These other monomers may be used individually or in combination of two or more.

[0039] From the viewpoint of easily improving tensile fracture strength, the maleic anhydride copolymer is preferably a copolymer of maleic anhydride and one or more other monomers selected from vinyl ether monomers, unsaturated dicarboxylic acid monomers, and olefin monomers, and more preferably a copolymer of maleic anhydride and one or more other monomers selected from vinyl ether monomers and olefin monomers.

[0040] Furthermore, from the viewpoint of easily improving tensile fracture strength, the number-average molecular weight (Mn) of the maleic anhydride copolymer is preferably 50,000 to 800,000, more preferably 100,000 to 800,000, and even more preferably 100,000 to 750,000. In one embodiment, the Mn may be 130,000 to 690,000. Also, from the viewpoint of easily obtaining molded products with greater tensile fracture strain, the Mn of the maleic anhydride copolymer may be 100,000 or more and less than 690,000, and may be 120,000 to 690,000.

[0041] In one embodiment, from the viewpoint of easily improving the affinity between the regenerated cellulose fiber (B) and the resin (a1), it is preferable to use a water-soluble maleic anhydride copolymer.

[0042] (Blocked polyisocyanate resin) Blocked polyisocyanate resin is an addition reaction product of polyisocyanate and a blocking agent, in which the blocking component is released by heating and the isocyanate groups are regenerated. In this case, it is preferable that there are two or more isocyanate groups at the ends. As the polyisocyanate, polyisocyanate compounds such as tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, and triphenylmethane triisocyanate are preferred, or urethane prepolymers (urethane resins containing terminal isocyanate groups) obtained by reacting the above polyisocyanate compounds with a compound having one or more active hydrogen atoms in a molar ratio of isocyanate groups (-NCO) to hydroxyl groups (-OH) (NCO / OH) greater than 1 are preferred because they tend to exhibit excellent performance. Examples of blocking agents include phenols such as phenol, thiophenol, cresol, and resorcinol; aromatic secondary amines such as diphenylamine and xylidine; phthalimides; lactams such as caprolactam and valerolactam; oximes such as acetoxime, methyl ethyl ketoxime, and cyclohexanone oxime; and acidic sodium sulfite. In one embodiment, the blocked polyisocyanate resin is preferably a reaction product of a polyisocyanate compound and a blocking agent, and more preferably a reaction product of diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), or hexamethylene diisocyanate (HDI) with methyl ethyl ketoxime. From the viewpoint of easily improving tensile fracture strength, a blocked polyisocyanate resin containing MDI or HDI is preferred. Furthermore, from the viewpoint of easily improving tensile fracture strain, a blocked polyisocyanate resin containing TDI may also be used. Commercially available products may be used as such blocked polyisocyanate resins, for example, products from Meisei Chemical Industry Co., Ltd., such as "Meikanate® DM-6700," "Meikanate TP-10," and "Meikanate NBP211," can be used.

[0043] (Epoxy resin) From the viewpoint of wettability with regenerated cellulose fibers (B), the epoxy resin is preferably water-soluble or water-dispersible. A polyfunctional epoxy resin is even more preferable.

[0044] Examples of epoxy resins include aromatic epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin; aliphatic epoxy resins such as diglycidyl ether epoxy resin and polyglycidyl ether epoxy resin; alicyclic epoxy resins; heterocyclic epoxy resins; and hydroxyl group-containing epoxy resins.

[0045] The epoxy equivalent of the epoxy resin may be 100 to 5,000 g / eq, 100 to 3,000 g / eq, 100 to 1,000 g / eq, or 100 to 500 g / eq. If the epoxy equivalent is within the above range, the water dispersibility of the epoxy resin when attached to the regenerated cellulose fiber (B) tends to be good. The epoxy equivalent represents the solid content epoxy equivalent and can be measured by a method in accordance with JIS K 7236.

[0046] Among the epoxy resins mentioned above, aromatic epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin are preferred.

[0047] In one embodiment, the number-average molecular weight (Mn) of the epoxy resin is preferably 200 to 20,000, and more preferably 300 to 10,000. Being within this range makes it easier to achieve good water dispersibility of the epoxy resin, and thus to achieve both good mechanical properties and moldability. The Mn of the epoxy resin can be determined by polystyrene equivalent using GPC (Gross Producing Control).

[0048] Commercially available epoxy resins may be used. Examples of commercially available products include the "BECKOPOX® series" from Daicel Ornex Co., Ltd., the "jER series" from Mitsubishi Chemical Corporation, and the "ADEKA Resin® EM series" from ADEKA Corporation.

[0049] When epoxy resin is used as additive (C), it is preferable to use a curing agent in combination. A polyamine compound having two or more amino groups in one molecule is preferably used as the curing agent. Examples of polyamine compounds include aliphatic polyamines, alicyclic polyamines, aromatic polyamines, polyoxyalkylene group-containing polyamines, polyoxyalkylene group-containing aromatic polyamines, and polyamidoamine compounds. These may be used individually or in combination of two or more. In one embodiment, the polyamine compound is preferably one with an active hydrogen equivalent of 100 to 350 g / eq, more preferably 100 to 250 g / eq, and even more preferably 150 to 250 g / eq. The active hydrogen equivalent of the polyamine compound represents the solid content active hydrogen equivalent and can be measured by a method compliant with JIS K 7237:1995.

[0050] (Epoxysilane compound) Epoxysilane compounds are silane compounds having an epoxy group (glycidyl group) as a functional group. Preferably, the epoxysilane compound is an alkoxysilane compound having one or more epoxy groups (glycidyl groups) in its molecule (preferably an alkoxysilane compound having 1 to 10 carbon atoms). Examples of epoxysilane compounds include 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropyltrimethoxysilane. These may be used individually or in combination of two or more.

[0051] (Isocyanate silane compounds) An isocyanate silane compound is a silane compound having an isocyanate group as a functional group. The isocyanate silane compound is preferably an alkoxysilane compound (preferably an alkoxysilane compound with 1 to 10 carbon atoms) having one or more isocyanate groups (glycidyl groups) in its molecule. Examples of isocyanate silane compounds include 3-isocyanate-propyltriethoxysilane and 3-isocyanate-propyltrimethoxysilane. These may be used individually or in combination of two or more.

[0052] (Polyamide epichlorohydrin resin) Polyamide epichlorohydrin resins are produced by reacting an epihalohydrin, such as epichlorohydrin, with the nitrogen in the main chain formed by condensing a polyhydric acid with a polyalkyl polyamine or urea. They contain a cationic quaternary amine and reactive functional groups. Polyamide epichlorohydrin resins also include polyamide polyamine epichlorohydrin resins. As the cationic quaternary amine, cyclic amino groups with four or fewer members, such as aziridinium groups and azetidinium groups, are preferred, and azetidinium groups, which combine the properties of a quaternary amine with those of a reactive functional group, are more preferred. In one embodiment, the polyamide epichlorohydrin resin preferably contains azetidinium groups and / or aziridinyl groups.

[0053] As the polyamide epichlorohydrin resin, for example, one with a viscosity of 5 to 1,000 mPa·s in a 25% aqueous solution at 25°C can be preferably used. Commercially available polyamide epichlorohydrin resins can also be used. Examples of commercially available products include the Sumirez® Resin series from Taoka Chemical Industries, Ltd. (e.g., "Sumirez Resin SLX-1") and the Arafix® series from Arakawa Chemical Industries, Ltd. (e.g., "Arafix 2550P" (polyamide polyamine epichlorohydrin resin)).

[0054] Additive (C) is one or more resin components selected from the above-mentioned maleic anhydride copolymer, blocked polyisocyanate resin, epoxy resin, epoxysilane compound, isocyanatesilane compound, and polyamide epichlorohydrin resin. Of these, from the viewpoint of obtaining molded articles with superior mechanical properties, it is preferable to include one or more selected from maleic anhydride copolymer, blocked polyisocyanate resin, and isocyanatesilane compound, more preferably to include maleic anhydride copolymer or blocked polyisocyanate resin, and even more preferably to include maleic anhydride copolymer.

[0055] The content of additive (C) in the resin composition according to the first embodiment is 0.01% by mass or more with respect to the total mass of the resin composition. If the content of additive (C) is 0.01% by mass or more, a molded article with superior mechanical properties can be obtained. The upper limit of the content of additive (C) is not particularly limited as long as the effects of this disclosure are achieved, but if the content of additive (C) is too high, the mechanical properties of the molded article may decrease, so it is preferably 10% by mass or less, and more preferably 5% by mass or less. In one embodiment, the content of additive (C) in the resin composition may be 0.01 to 5% by mass, or 0.05 to 1% by mass, with respect to the total mass of the resin composition. In one embodiment, when additive (C) contains a maleic anhydride copolymer, the content of additive (C) relative to the total mass of the resin composition is preferably 0.1 to 10% by mass, and more preferably 1 to 5% by mass.

[0056] In one embodiment, the ratio of additive (C) to 100 parts by mass of resin (A) is preferably 0.01 to 1.25 parts by mass, more preferably 0.05 to 1.20 parts by mass, and even more preferably 0.1 to 1.05 parts by mass. In one embodiment, if additive (C) contains a maleic anhydride copolymer, the ratio of additive (C) to 100 parts by mass of resin (A) may be 1.1 to 12.6 parts by mass, or 1.1 to 7.7 parts by mass.

[0057] In one embodiment, the ratio of additive (C) to 100 parts by mass of regenerated cellulose fiber (B) is preferably 0.1 to 7 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.3 to 4 parts by mass. In one embodiment, if additive (C) contains maleic anhydride copolymer, the ratio of additive (C) to 100 parts by mass of regenerated cellulose fiber (B) may be 10 to 100 parts by mass, or 10 to 50 parts by mass.

[0058] <Other ingredients (D)> The resin composition according to the first embodiment may contain components other than resin (A), regenerated cellulose fiber (B), and additive (C) (other components (D)) within a range that does not impede the effects of the present invention. Examples of other components include additives such as softeners, surface lubricants, leveling agents, antioxidants, surfactants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, heat stabilizers, polymerization inhibitors, lubricants, plasticizers, crystallization accelerators, hydrolysis inhibitors, inorganic fillers, colorants, mold release agents, antistatic agents, organic fillers other than regenerated cellulose fiber (B), metal powders, pigments, epoxy compounds, and binder resins (excluding resin (A) and additive (C)). These additives may be used individually or in combination of two or more.

[0059] Furthermore, if the resin composition contains the aforementioned other component (D), its amount may be 1% by mass or less relative to the total mass of the resin composition. Note that the other component (D) may be blended during the production of the fiber bundle (B-1), or it may be attached to at least a portion of the surface of the pellets of the resin composition described later.

[0060] [Method for producing resin compositions] A second embodiment of this disclosure relates to a method for producing a resin composition according to the first embodiment. The production method according to the second embodiment includes preparing a precursor (hereinafter sometimes referred to as "step (1)") and obtaining the resin composition from the precursor (hereinafter sometimes referred to as "step (2)"), wherein preparing the precursor includes obtaining a mixture containing the thermoplastic resin (A) and the additive (C) (hereinafter sometimes referred to as "step (1-1)"), or obtaining the regenerated cellulose fibers (B) to which the additive (C) is attached (hereinafter sometimes referred to as "step (1-2)"). Details of each step will be described below.

[0061] <Process (1)> Step (1) is to prepare the precursor. Here, "precursor" refers to a mixture containing resin (A) and additive (C), or regenerated cellulose fibers (B) to which additive (C) is attached. Step (1) includes step (1-1) or step (1-2).

[0062] (Process (1-1) Step (1-1) is to obtain a mixture containing resin (A) and additive (C). Step (1-1) adjusts the amount of additive (C) added so that the proportion of additive (C) in the final resin composition is 0.01% by mass or more. In one embodiment, additive (C) may be added in amounts of 0.01 to 1.25 parts by mass, 0.05 to 1.20 parts by mass, or 0.1 to 1.05 parts by mass per 100 parts by mass of resin (A). In one embodiment, if additive (C) contains a maleic anhydride copolymer, the proportion of additive (C) per 100 parts by mass of resin (A) may be 1.1 to 12.6 parts by mass or 1.1 to 7.7 parts by mass. Methods for adding additives (C) to resin (A) include, for example, pre-blending using a coil screw or a locking mixer.

[0063] <Process (1-2)> Step (1-2) is to obtain regenerated cellulose fibers (B) to which additive (C) is attached. In one embodiment, step (1-2) preferably includes attaching additive (C) to at least a portion of the surface of the regenerated cellulose fibers (B) using a sizing machine. Specifically, this could be done by attaching additive (C) to at least a portion of the surface of a fiber bundle of regenerated cellulose fibers (B) bundled in the length direction using a sizing machine, and then cutting it to a predetermined length with a cutting machine (Method 1), or by attaching additive (C) to at least a portion of the surface of a monofilament of regenerated cellulose using a sizing machine to obtain a monofilament to which additive (C) is attached, and then bundling a predetermined amount of the monofilament to form a fiber bundle (Method 2). In the case of Method 1, a fiber bundle of regenerated cellulose fibers (B) to which additive (C) is attached can be obtained to at least a portion of the surface of the fiber bundle. In the case of Method 2, a fiber bundle to which additive (C) is attached can be obtained to at least a portion of the surface and / or at least a portion of the spaces between the fibers.

[0064] Step (1-2) adjusts the amount of additive (C) attached so that the proportion of additive (C) in the final resin composition is 0.01% by mass or more. In one embodiment, 0.1 to 7 parts by mass of additive (C) may be attached to 100 parts by mass of regenerated cellulose fiber (B), or 0.1 to 5 parts by mass, or 0.3 to 4 parts by mass. In one embodiment, if additive (C) contains a maleic anhydride copolymer, the ratio of additive (C) to 100 parts by mass of regenerated cellulose fiber (B) may be 10 to 100 parts by mass, or 10 to 50 parts by mass.

[0065] <Process (2)> Step (2) is to obtain a resin composition from the precursor obtained in step (1). Step (2) may include the following steps (2-1) or (2-2).

[0066] (Process (2-1)) Step (2-1) is to add regenerated cellulose fibers (B) to the mixture obtained in step (1-1), or to add regenerated cellulose fibers (B) to which additive (C) obtained in step (1-2) is attached to the resin (A). When carrying out step (2-1), the amount of regenerated cellulose fibers (B) added is adjusted so that the proportion of regenerated cellulose fibers (B) in the final resin composition is 3 to 60% by mass. In one embodiment, regenerated cellulose fibers (B) may be added so that the mass ratio of the mixture to the regenerated cellulose fibers (B) (mixture: regenerated cellulose fibers (B)), or the mass ratio of the resin (A) to the regenerated cellulose fibers (B) to which additive (C) is attached (resin (A): regenerated cellulose fibers (B) with additive (C) attached) is 50:50 to 95:5.

[0067] In one embodiment, step (2-1) is preferably performed when short fibers (average fiber length of 1 to 3 mm) are used as the regenerated cellulose fibers (B) (short fiber formulation). In this case, chopped strands are preferably used as the regenerated cellulose fibers (B) added to the mixture or resin (A). In the resin composition obtained by the manufacturing method comprising step (1-1) and step (2-1), the average fiber length of the regenerated cellulose fibers (B) in the resin composition may be 100 to 5,000 μm, 120 to 1,500 μm, or 150 to 500 μm.

[0068] (Process (2-2)) Step (2-2) is to impregnate the fiber bundle of regenerated cellulose fibers (B) with the mixture obtained in step (1-1) as an impregnation resin, or to impregnate the fiber bundle of regenerated cellulose fibers (B) to which the additive (C) obtained in step (1-2) is attached with resin (A). Step (2-2) is preferably performed when obtaining the aforementioned fiber bundle (B-1) as a resin composition. That is, step (2-2) includes impregnating the fiber bundle, which is made by bundling regenerated cellulose fibers (B) (or regenerated cellulose fibers (B) to which the additive (C) is attached) aligned in the length direction, with the mixture or resin (A). As a method for impregnating with the mixture or resin (A), the embodiment described in the method for producing the fiber bundle (B-1) above can be adopted.

[0069] In one embodiment, step (2-2) is preferably performed when continuous fibers of regenerated cellulose fiber (B) (long fiber) are used (long fiber formulation). In the resin composition prepared by the manufacturing method including step (2-2) (for example, the fiber bundle (B-1) described above), the average fiber length of the regenerated cellulose fiber (B) in the resin composition may be 100 to 5,000 μm or 1,000 to 4,000 μm. If the manufacturing method according to the second embodiment is a long fiber formulation, for example, regenerated cellulose fibers (B) (or regenerated cellulose fibers (B) with additive (C) attached) passed through a crosshead die may be aligned in the length direction, impregnated with the mixture or resin (A) to integrate them, and then cut to any length to obtain the resin composition as the above-mentioned fiber bundle (B-1).

[0070] <Other forms> The resin composition according to the first embodiment may be produced by a manufacturing method that includes feeding resin (A) and regenerated cellulose fibers (B) into an extruder, and then feeding additive (C) through a side feeder to obtain the resin composition. Alternatively, the resin composition may be obtained by mixing each of the components (A) to (C).

[0071] [pellet] A third embodiment in this disclosure relates to pellets comprising a resin composition according to the first embodiment. The pellets according to the third embodiment can be obtained by manufacturing the resin composition by the manufacturing method according to the second embodiment.

[0072] [Molded articles and methods for manufacturing the same] A fourth embodiment in this disclosure relates to a molded article comprising a resin composition according to the first embodiment. The molded article according to the fourth embodiment is obtained by molding the resin composition according to the first embodiment (or the pellets according to the third embodiment). The molded article according to the fourth embodiment may also be obtained by injection molding the resin composition according to the first embodiment (or the pellets according to the third embodiment). The molded article according to the fourth embodiment has superior mechanical properties.

[0073] In one embodiment, when the resin composition is a short fiber formulation, the tensile breaking strength (measured in accordance with ISO 527) of the molded article is preferably 50 MPa or higher. In another embodiment, the tensile breaking strength is preferably 55 MPa or higher, and more preferably 60 MPa or higher. Molded articles with such excellent mechanical properties are easily obtained in resin compositions in which the proportion of regenerated cellulose fibers (B) is 10% by mass or more (preferably 30% by mass or more). Through the inventors' studies, it was found that even if the proportion of regenerated cellulose fibers (B) in the resin composition is increased, as shown in Comparative Examples 1 to 4, the desired mechanical properties cannot be obtained. On the other hand, it was found that molded articles obtained from the resin composition according to the first embodiment tend to have high mechanical properties even when the proportion of regenerated cellulose fibers (B) is as low as 5 to 10% by mass, and that further increasing the proportion of regenerated cellulose fibers (B) can result in molded articles with even better mechanical properties.

[0074] In one embodiment, when the resin composition is a long fiber formulation, the tensile fracture strength of the molded article (measured in accordance with ISO 527) is preferably 66 MPa or higher, and preferably 70 MPa or higher.

[0075] [Application] The molded article according to the fourth embodiment exhibits superior mechanical properties. Such molded articles can be suitably used in applications such as shoe soles and bicycle parts.

[0076] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of this disclosure is provided below. [1] A resin composition, With respect to the total mass of the resin composition, A thermoplastic resin (A) containing polyamide resin (a1) in a mass of 40-97%, Regenerated cellulose fiber (B) 3-60% by mass, A resin composition comprising one or more additives (C) selected from maleic anhydride copolymers, blocked polyisocyanate resins, epoxy resins, epoxysilane compounds, isocyanatesilane compounds, and polyamide epichlorohydrin resins, in an amount of 0.01% by mass or more (provided that the sum of (A) to (C) does not exceed 100% by mass). [2] The resin composition according to [1], wherein the melting point of the polyamide resin (a1) is 100 to 280°C. [3] The resin composition according to [1] or [2], wherein the polyamide resin (a1) comprises one or more selected from a polyamide resin (a11) having repeating units represented by the following formula (I), a polyamide resin (a12) having repeating units represented by the following formula (II), and a polyamide resin (a13) having repeating units represented by the following formula (III). [ka] (In equation (I), m1 represents a number between 3 and 11, and n1 represents a number greater than or equal to 10.) [ka] (In equation (II), m2 represents a number between 4 and 10, m3 represents a number between 4 and 10, and n2 represents a number greater than or equal to 10.) [ka] (In equation (III), m4 and m5 represent numbers from 1 to 3, m6 represents numbers from 4 to 18, and n3 represents numbers greater than or equal to 10.) [4] The resin composition according to any one of [1] to [3], wherein the additive (C) comprises one or more selected from the maleic anhydride copolymer, the block polyisocyanate resin, and the isocyanate silane compound. [5] The resin composition according to any one of [1] to [4], wherein the regenerated cellulose fiber (B) comprises a solvent-regenerated cellulose fiber. [6] The resin composition according to any one of [1] to [5], wherein the resin composition comprises a thermoplastic resin-impregnated regenerated cellulose fiber bundle (B-1) in which the regenerated cellulose fibers (B) are aligned in the longitudinal direction and the thermoplastic resin (A) containing the additive (C) is impregnated into the fiber bundle. A pellet comprising the resin composition described in any of [7], [1], to [6]. A molded article comprising the resin composition described in any of [8], [1] to [6]. A method for producing a resin composition according to any one of [9], [1] to [6], The manufacturing method includes preparing a precursor and obtaining the resin composition from the precursor. A method for producing a resin composition, comprising preparing the precursor to obtain a mixture containing the thermoplastic resin (A) and the additive (C), or to obtain the regenerated cellulose fiber (B) to which the additive (C) is attached. [Examples]

[0077] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following description.

[0078] The following were used as raw materials for the resin composition. <Thermoplastic resin (A)> (a1): Resin (a11) Polyamide 12 (manufactured by Polypla Evonik Co., Ltd., product name "Diamide® L1600", melting point: 178℃, melt flow rate (190℃, 2.16kg load): 84g / 10min).

[0079] <Regenerated cellulose fiber (B)> (B1): Chopped strands of solvent-regenerated cellulose fiber (Lenzing, product name "Lyocell® dull", fiber length: 2 mm, average fiber diameter (longest diameter): 13 μm). (B2): Continuous fibers of solvent-regenerated cellulose (manufactured by Biomid Fiber, product name "Biomid Fiber®", average fiber diameter (longest diameter): 11 μm).

[0080] <Additive (C)> (C1): Water-soluble maleic anhydride copolymer (polymer of methyl vinyl ether and maleic anhydride (manufactured by Ashland Japan Co., Ltd., product name "GANTREZ® AN-119", number average molecular weight: 130,000)). (C2): Water-soluble maleic anhydride copolymer (polymer of methyl vinyl ether and maleic anhydride (manufactured by Ashland Japan Co., Ltd., product name "GANTREZ AN-139", number average molecular weight: 690,000)). (C3): Blocked polyisocyanate resin (reaction product of MDI and methyl ethyl ketoxime, manufactured by Meisei Chemical Industry Co., Ltd., product name "DM-6400"). (C4): Epoxy resin (bisphenol A / F type epoxy resin that can be emulsified in water, epoxy equivalent: 194 g / eq, solids content: 100% by mass, manufactured by Daicel Ornex Co., Ltd., product name "BECKOPOX EP 147w"). (C5): Epoxy resin curing agent (polyamine compound, active hydrogen equivalent 210 g / eq, manufactured by T&K TOKA Corporation, product name "Tomide (registered trademark) TXS-53-C"). (C6): Polyamide epichlorohydrin (manufactured by Taoka Chemical Co., Ltd., product name "SLX-1"). (C7): 3-Glycidoxypropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KBE-403"). (C8): 3-Isocyanate-propyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KBE-9007N"). (C9): Maleic anhydride-modified HDPE (manufactured by BIC Chemie Japan Co., Ltd., product name "SCONA® TPPE 1212 PAHD"). (C'1): Water-based polyurethane resin (manufactured by Meisei Chemical Industry Co., Ltd., product name "V-400"). (C'2):3-Aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KBE-903").

[0081] <Other ingredients (D)> (D1): Hindered phenol antioxidant (manufactured by BASF Japan Ltd., product name "Irganox® 1010").

[0082] [Example 1] Steps (1-2) and (2-1) were carried out to prepare the resin composition of Example 1. Specifically, regenerated cellulose fibers (B1), 10 times the amount of pure water as regenerated cellulose fibers (B1), and additive (C1) were placed in a container and stirred at 300 rpm for 30 minutes using a three-blade stirrer. After that, the mixture was heated to 80°C to evaporate the water, and then dried at 120°C for 7 hours to adhere the additive (C1) to the surface of the regenerated cellulose fibers (B1). The amount of additive (C1) attached to 100 parts by mass of regenerated cellulose fibers (B1) was 1 part by mass (solid content). Subsequently, the regenerated cellulose fibers (B1) with additive (C1) attached, along with resin (A1) and antioxidant (D1), were fed into a 30mmφ twin-screw extruder (TEX30α, manufactured by Japan Steel Works Ltd.). The cylinder temperatures at the raw material supply section and the die tip were set to 200°C, with the temperature between them set to 180-200°C. The mixture was melt-kneaded and extruded at a discharge rate of 20kg / h and a screw rotation speed of 200rpm. The mixture was then cut into 5mm lengths using a pelletizer to obtain resin compositions (pellets) having the composition shown in Table 1. In Table 1, the additive (C) value represents the percentage of solid content in the resin composition.

[0083] Next, the resin composition (pellets) of Example 1 was injection molded under the following conditions to obtain molded articles (ISO tensile test specimens). Various mechanical properties of the obtained molded articles were measured under the following conditions. (Molding conditions) Molding machine: Manufactured by Sumitomo Heavy Industries, Ltd., product name "SE100EV-A". Test specimen: ISO tensile test specimen. Molding temperature: 200℃. Mold temperature: 90℃.

[0084] <Evaluation of mechanical properties> • Measurement of tensile fracture strength and tensile fracture strain The obtained ISO tensile test specimens were measured in accordance with ISO 527. Specifically, a tensile testing machine (manufactured by Shimadzu Corporation, product name "Autograph® AG-20kNXDplus") was used, with the following conditions: temperature: 23°C, test speed: 5 mm / min, and chuck distance (span): 115 mm.

[0085] [Examples 2-17] A resin composition was obtained in the same manner as in Example 1, except that the proportion of regenerated cellulose fibers (B1) in the resin composition and the type and amount of additive (C) were as shown in Table 1. A molded article was prepared from the obtained resin composition in the same manner as in Example 1, and various mechanical properties of the molded article were measured. The results are shown in Table 1.

[0086] [Comparative Examples 1-6] Comparative Examples 1 to 4 were prepared using the same method as in Example 1, except that the step of attaching additive (C) to the regenerated cellulose fibers (B1) was omitted. Comparative Example 5 was prepared using the same method as in Example 1, except that additive (C'1) was attached to the regenerated cellulose fibers (B1). Comparative Example 6 was prepared using the same method as in Example 1, except that additive (C'2) was attached to the regenerated cellulose fibers (B1). Molded articles were prepared from the obtained resin compositions in the same manner as in Example 1, and various mechanical properties of the molded articles were measured. The results are shown in Table 2.

[0087] [Example 18] A mixture of 69.6% by mass of resin (A1), 0.3% by mass of additive (C1), and 0.1% by mass of antioxidant (D1) was fed into a twin-screw extruder. The mixture was then melt-kneaded at a cylinder temperature of 220°C to obtain a molten mixture. This molten mixture was then impregnated into fiber bundles of regenerated cellulose fibers (B2) that had been passed through a crosshead die and aligned in the length direction, so that the regenerated cellulose fibers (B2) comprised 30% by mass. Subsequently, the bundles were shaped using a shaping nozzle at the crosshead die outlet, shaped with shaping rolls, and then cut into 7 mm lengths using a pelletizer to obtain the resin composition of Example 13, consisting of pellet-shaped fiber bundles (B-1). Molded articles were prepared from the obtained resin composition in the same manner as in Example 1, and various mechanical properties of the molded articles were measured. The results are shown in Table 3.

[0088] [Examples 19-23 and Comparative Example 7] The resin compositions for each example were obtained in the same manner as in Example 18, except that the content of resin (A) and additive (C), and the type of additive (C) were as shown in Table 3. Molded articles were prepared from the obtained resin compositions in the same manner as in Example 1, and various mechanical properties of the molded articles were measured. The results are shown in Table 3. [Table 1]

[0089] [Table 2]

[0090] [Table 3]

[0091] As shown in Tables 1-2, the molded articles of Examples 1-17 obtained from the resin composition according to the first embodiment exhibited superior mechanical properties compared to the molded articles of Comparative Examples 1-4 which did not contain additive (C). As shown in Comparative Examples 1-4, it can be seen that in formulations simply combining resin (a1) and regenerated cellulose fibers (B), increasing the proportion of regenerated cellulose fibers (B) did not improve mechanical properties. Furthermore, the molded articles of Comparative Examples 5-6, in which (C'1) or (C'2) was attached to the regenerated cellulose fibers (B1), had inferior mechanical properties compared to the molded articles of Examples 1-17. From these results, it was confirmed that by combining resin (a1), regenerated cellulose fibers (B), and additive (C), it is possible to obtain molded articles with superior mechanical properties. Also, as shown in Table 3, even in long-fiber formulations, the molded articles obtained from the resin composition according to the first embodiment exhibited better mechanical properties than the molded article of Comparative Example 7 which did not contain additive (C). From these results, it was found that the resin composition according to the first embodiment can provide molded articles with superior mechanical properties.

Claims

1. A resin composition, With respect to the total mass of the resin composition, A thermoplastic resin (A) containing polyamide resin (a1) in an amount of 40 to 97% by mass, Regenerated cellulose fiber (B) 3-60% by mass, A resin composition comprising: one or more additives (C) selected from maleic anhydride copolymers, block polyisocyanate resins, epoxy resins, epoxysilane compounds, isocyanatesilane compounds, and polyamide epichlorohydrin resins, in an amount of 0.01% by mass or more (provided that the sum of (A) to (C) does not exceed 100% by mass).

2. The resin composition according to claim 1, wherein the melting point of the polyamide resin (a1) is 100 to 280°C.

3. The resin composition according to claim 1 or 2, wherein the polyamide resin (a1) comprises one or more selected from a polyamide resin (a11) having repeating units represented by the following formula (I), a polyamide resin (a12) having repeating units represented by the following formula (II), and a polyamide resin (a13) having repeating units represented by the following formula (III). 【Chemistry 1】 (In equation (I), m1 represents a number between 3 and 11, and n1 represents a number greater than or equal to 10.) 【Chemistry 2】 (In equation (II), m² represents a number between 4 and 10, m³ represents a number between 4 and 10, and n² represents a number greater than or equal to 10.) 【Transformation 3】 (In formula (III), m4 and m5 represent numbers from 1 to 3, m6 represents numbers from 4 to 18, and n3 represents numbers of 10 or greater.)

4. The resin composition according to claim 1 or 2, wherein the additive (C) comprises one or more selected from the maleic anhydride copolymer, the block polyisocyanate resin, and the isocyanate silane compound.

5. The resin composition according to claim 1 or 2, wherein the regenerated cellulose fiber (B) includes solvent-regenerated cellulose fiber.

6. The resin composition according to claim 1 or 2, wherein the resin composition comprises a thermoplastic resin-impregnated regenerated cellulose fiber bundle (B-1), in which a fiber bundle of the regenerated cellulose fibers (B) aligned in the longitudinal direction is impregnated with the thermoplastic resin (A) containing the additive (C).

7. A pellet comprising the resin composition according to claim 1 or 2.

8. A molded article comprising the resin composition according to claim 1 or 2.

9. A method for producing the resin composition according to claim 1 or 2, The manufacturing method includes preparing a precursor and obtaining the resin composition from the precursor. A method for producing a resin composition, comprising preparing the precursor to obtain a mixture containing the thermoplastic resin (A) and the additive (C), or to obtain the regenerated cellulose fiber (B) to which the additive (C) is attached.

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