Sizing agent for reinforcement fiber and reinforcement fiber

Abstract

To provide a sizing agent for a reinforcement fiber which can reduce fuzzing, and a reinforcement fiber obtained from the same.SOLUTION: A sizing agent for a reinforcement fiber contains a resin (A), and a non-ionic surface active agent (B), wherein the non-ionic surface active agent (B) contains the following (poly)oxyalkylene derivative (B1). The (poly)oxyalkylene derivative (B1) represents a compound obtained by adding a total of 1 mol or more and 100 mol or less of at least one alkylene oxide selected from an ethylene oxide and a propylene oxide to 1 mol of alcohol represented by the following general formula (1). In the general formula (1), R1 represents a hydrocarbon group having one or more double bonds and 10 or more and 20 or less carbon atoms.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a sizing agent for reinforcing fibers capable of reducing fuzz, and to reinforcing fibers obtained therefrom. [Background technology]

[0002] In general, fiber-reinforced resin composite materials are known as materials containing reinforcing fibers such as carbon fibers and a matrix resin such as a thermoplastic resin or a thermosetting resin as a base material, and are widely used in various fields such as building materials and transportation equipment. In order to improve the adhesiveness at the interface between the reinforcing fibers such as carbon fibers and the matrix resin, a treatment of attaching a sizing agent to the reinforcing fibers may be performed.

[0003] Conventionally known sizing compositions for carbon fibers are disclosed, for example, in Patent Document 1. Patent Document 1 discloses a sizing composition for carbon fibers that contains a bundling agent such as an epoxy resin, and an alkylene oxide adduct of distyrenated phenol and an alkylene oxide adduct of tristyrenated phenol as nonionic surfactants. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-099942 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional sizing agents for reinforcing fibers have a problem in that they are insufficient in reducing the fuzz of the reinforcing fibers to which the sizing agent for reinforcing fibers is applied. [Means for solving the problem]

[0006] As a result of research aimed at solving the above problems, the present inventors have found that a sizing agent for reinforcing fibers containing a (poly)oxyalkylene derivative of a specified aromatic alcohol as a nonionic surfactant is precisely suitable.

[0007] Various aspects for solving the above problems will be described below. The sizing agent for reinforcing fibers of aspect 1 is a sizing agent for reinforcing fibers containing a resin (A) and a nonionic surfactant (B), characterized in that the nonionic surfactant (B) contains the following (poly)oxyalkylene derivative (B1).

[0008] (Poly)oxyalkylene derivative (B1): A compound in which a total of 1 mole or more and 100 moles or less of at least one alkylene oxide selected from ethylene oxide and propylene oxide is added to 1 mole of an alcohol represented by the following general formula (1).

[0009] [ka] (In Chemical Formula 1, R 1 : A hydrocarbon group having 10 to 20 carbon atoms and one or more double bonds. A second aspect is the sizing agent for reinforcing fibers according to the first aspect, wherein the resin (A) includes an epoxy resin (A1).

[0010] Aspect 3 is the sizing agent for reinforcing fibers according to Aspect 1 or 2, in which the content of the (poly)oxyalkylene derivative (B1) in the non-volatile content of the sizing agent for reinforcing fibers is 1% by mass or more and 50% by mass or less.

[0011] A fourth aspect is the sizing agent for reinforcing fibers according to any one of the first to third aspects, in which the nonionic surfactant (B) contains the following (poly)oxyalkylene derivative (B2).

[0012] (Poly)oxyalkylene derivative (B2): A compound obtained by adding at least one alkylene oxide selected from ethylene oxide and propylene oxide to an aromatic alcohol other than the alcohol represented by the above general formula (1).

[0013] The reinforcing fiber of the fifth aspect is characterized in that the sizing agent for reinforcing fibers according to any one of the first to fourth aspects is adhered thereto. A sixth aspect is the reinforcing fiber according to the fifth aspect, wherein the reinforcing fiber is a carbon fiber or a glass fiber. Effect of the Invention

[0014] According to the present invention, it is possible to reduce fluff in reinforcing fibers to which a sizing agent for reinforcing fibers has been applied. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 shows a schematic diagram of the composite interface property evaluation device used to evaluate the adhesion in the Examples section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] First Embodiment Hereinafter, a first embodiment of the sizing agent for reinforcing fibers (hereinafter, simply referred to as the sizing agent) of the present invention will be described. The sizing agent of this embodiment contains a resin (A) and a nonionic surfactant (B) described later.

[0017] (Resin (A)) The resin (A) used in the sizing agent of this embodiment is appropriately selected from known resins depending on the application of the reinforcing fiber to which the sizing agent is applied. Specific examples of the resin include epoxy resin, vinyl ester resin, polyamide resin, polyolefin resin, polyurethane resin, polycarbonate resin, polyester resin, PEEK resin, fluororesin, phenoxy resin, phenol resin, BMI resin, polyimide resin, polyimide resin precursor, polyethersulfone resin, polyetherester resin, polyacrylic resin, etc. These resins may be used alone or in combination of two or more. Among these, when applied to a fiber-reinforced resin composite material, epoxy resin is preferred from the viewpoint of improving the adhesion between the reinforcing fiber to which the sizing agent is applied and the resin.

[0018] Specific examples of the resin include epoxy resins (manufactured by Mitsubishi Chemical Corporation: trade names: jER828, jER1002, jER1001, and manufactured by Nagase ChemteX Corporation: trade name: Denacol EX-421), vinyl ester resins (bisphenol A diglycidyl ether methacrylic acid adduct, 2 mol ethylene oxide-added bisphenol A acrylic acid adduct, 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid), polyurethane resins (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.: trade name: Superflex 740, Daiichi Kogyo Seiyaku Co., Ltd.: Superflex 650, ADEKA Co., Ltd.: Adekabon Lighter HUX-564, Toyo Polymer Co., Ltd.: MELUSI 6900), modified polypropylene resin (Maruyoshi Chemical Co., Ltd.: MGP-1650), modified polypropylene resin (Toho Chemical Industry Co., Ltd.: Hi-Tec P-9018), polyester resin (Toyobo Co., Ltd.: Vylonal MD-1480, Sanyo Chemical Industries Co., Ltd.), polyester resin (Sanyo Chemical Industries Co., Ltd.), Polyester resin (manufactured by Sanyo Chemical Industries, Ltd.) Product name: Polyester resin esterified with Newpol BPE-20 (a 2-mol adduct of ethylene oxide with bisphenol A) and maleic acid to give a molar ratio of hydroxyl value / acid value of 4 / 3), polyester resin (manufactured by Sanyo Chemical Industries, Ltd. Product name: Polyester resin esterified with Newpol BPE-40 (a 4-mol adduct of ethylene oxide with bisphenol A) and fumaric acid to give a molar ratio of hydroxyl value / acid value of 5 / 4), polyester resin (manufactured by Sanyo Chemical Industries, Ltd.) : Trade name: Newpol BPE-100 (polyester resin esterified with 10 moles of ethylene oxide adduct of bisphenol A) and adipic acid in a molar ratio of hydroxyl value / acid value = 6 / 5), polyacrylic resin (ammonia neutralized copolymer of maleic anhydride and n-butyl methacrylate, sodium neutralized copolymer of acrylic acid and 2-hydroxyethylacrylamide), phenoxy resin (Nippon Steel Chemical & Material Co., Ltd.: Trade name: YP-50S), 3,3',4,Examples of such resins include a polyimide resin precursor of 4'-biphenyltetracarboxylic anhydride and diaminodiphenyl ether, a polyamide resin (manufactured by Toray Industries, Inc.: product name: AQ nylon P-95), a polyether ester resin of an ethylene oxide 2-mol adduct of bisphenol A and fumaric acid, an epoxy resin and a vinyl ester resin of methacrylic acid, and a copolymer (polyether ester resin) of polyethylene glycol with an average molecular weight of 2000, dimethyl terephthalate, and lauryl alcohol.

[0019] When the reinforcing fibers are applied to a fiber-reinforced resin composite material, the type of resin to be blended into the sizing agent may be selected in consideration of the type of base material constituting the fiber-reinforced resin composite material from the standpoint of improving adhesion, improving recyclability, etc.

[0020] The lower limit of the content of the resin (A) in the non-volatile content of the sizing agent is set appropriately, but is preferably 10% by mass or more, more preferably 20% by mass or more. When the content is 10% by mass or more, the adhesion between the reinforcing fiber to which the sizing agent is applied and the resin can be improved. The upper limit of the content of the resin (A) is set appropriately, but is preferably 90% by mass or less, more preferably 80% by mass or less. When the content is 90% by mass or less, the stability of the sizing agent can be improved. Note that a range in which the above upper and lower limits are arbitrarily combined is also envisaged.

[0021] The non-volatile content of the sizing agent refers to the residue after the measurement sample is heat-treated at 105° C. for 2 hours (the same applies below). (Nonionic Surfactant (B)) The nonionic surfactant (B) used in this embodiment contains the following (poly)oxyalkylene derivative (B1). The (poly)oxyalkylene derivative (B1) can reduce fluff in the reinforcing fiber to which a sizing agent has been applied. It can also improve adhesion between the reinforcing fiber to which a sizing agent has been applied and the resin.

[0022] ((Poly)oxyalkylene derivative (B1)) The (poly)oxyalkylene derivative (B1) is a compound in which a total of 1 to 100 moles of at least one alkylene oxide selected from ethylene oxide and propylene oxide is added to 1 mole of an aromatic alcohol represented by the following general formula (1).

[0023] [ka] (In Chemical Formula 2, R 1 : A hydrocarbon group having 10 to 20 carbon atoms and one or more double bonds. R 1 The hydrocarbon group having one or more double bonds may be an alkenyl group having one double bond, or an alkadienyl group or an alkatrienyl group having two or more double bonds. The hydrocarbon group may have a linear or branched chain structure. The number of carbon atoms in the hydrocarbon group is 10 to 20, preferably 12 to 18, more preferably 14 to 16. Any combination of the upper and lower limits above is also contemplated.

[0024] Specific examples of unsaturated hydrocarbon groups having one double bond in the hydrocarbon group include a decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, a heptadecenyl group, an octadecenyl group, and an icocenyl group.

[0025] Specific examples of unsaturated hydrocarbon groups having two double bonds in the hydrocarbon group include decadienyl, undecadienyl, dodecadienyl, tridecadienyl, tetradecadienyl, pentadecadienyl, hexadecadienyl, heptadecadienyl, octadecadienyl, and icosadienyl groups.

[0026] Specific examples of unsaturated hydrocarbon groups having three double bonds in the hydrocarbon group include, for example, a decatrienyl group, an undecatrienyl group, a dodecatrienyl group, a tridecatrienyl group, a tetradecatrienyl group, a pentadecatrienyl group, a hexadecatrienyl group, a heptadecatrienyl group, an octadecatrienyl group, and an icosatrienyl group.

[0027] The ethylene oxide and propylene oxide added to the aromatic alcohol may be ethylene oxide alone, propylene oxide alone, or both ethylene oxide and propylene oxide. When two types of alkylene oxide are used, the addition form may be any of block addition, random addition, and a combination of block addition and random addition, and is not particularly limited. In addition to ethylene oxide or propylene oxide, butylene oxide, etc. may be added as the alkylene oxide.

[0028] The number of moles of alkylene oxide added is 1 mole or more and 100 moles or less, preferably 2 moles or more and 60 moles or less. Any combination of the upper and lower limits above is also possible. The number of moles of alkylene oxide added indicates the number of moles of alkylene oxide per mole of aromatic alcohol in the raw material.

[0029] Specific examples of the (poly)oxyalkylene derivative (B1) include compounds in which alkylene oxide is added to cardanol, 3-[(8Z,11Z)-8,11,14-pentadecatrienyl]phenol, etc. The aromatic monoalcohol used as the raw material may be a chemically synthesized product, or may be a naturally derived mixture such as cardanol obtained from cashew nut shell liquid.

[0030] These (poly)oxyalkylene derivatives (B1) may be used alone or in appropriate combination of two or more. ((Poly)oxyalkylene derivative (B2)) The nonionic surfactant (B) used in this embodiment preferably contains the following (poly)oxyalkylene derivative (B2). The (poly)oxyalkylene derivative (B2) is a compound obtained by adding at least one alkylene oxide selected from ethylene oxide and propylene oxide to an aromatic alcohol other than the alcohol represented by the general formula (1). When the sizing agent contains the (poly)oxyalkylene derivative (B2), the adhesion between the reinforcing fiber to which the sizing agent is applied and the resin can be improved.

[0031] Specific examples of aromatic alcohols other than the alcohol represented by the general formula (1) include phenol, nonylphenol, benzyl alcohol, monostyrenated phenol, distyrenated phenol, and tristyrenated phenol.

[0032] Examples of alkylene oxides used as raw materials for forming the (poly)oxyalkylene structure of the (poly)oxyalkylene derivative (B2) include ethylene oxide and propylene oxide. The number of moles of alkylene oxide added is appropriately set, but is preferably 1 mole or more and 60 moles or less, more preferably 2 moles or more and 50 moles or less. Any combination of the upper and lower limits above is also possible. The number of moles of alkylene oxide added indicates the number of moles of alkylene oxide per mole of aromatic alcohol in the charged raw material. The alkylene oxide may be one type of alkylene oxide used alone, or two types of alkylene oxides may be used in appropriate combination. When two types of alkylene oxides are used, the addition form may be any of block addition, random addition, and a combination of block addition and random addition, and is not particularly limited.

[0033] Specific examples of the (poly)oxyalkylene derivative (B2) include a compound in which an alkylene oxide is added to tristyrenated phenol, a compound in which an alkylene oxide is added to distyrenated phenol, and a compound in which an alkylene oxide is added to nonylphenol.

[0034] These (poly)oxyalkylene derivatives (B2) may be used alone or in appropriate combination of two or more. (Other nonionic surfactants (B3)) Furthermore, a nonionic surfactant (B3) other than the above-mentioned (poly)oxyalkylene derivative (B1) and (poly)oxyalkylene derivative (B2) may be blended.

[0035] Other examples of the nonionic surfactant (B3) include compounds having a (poly)oxyalkylene structure in which alkylene oxide is added to alcohols or carboxylic acids, ether / ester compounds having a (poly)oxyalkylene structure in which alkylene oxide is added to an ester compound of carboxylic acids and polyhydric alcohols, amine compounds having a (poly)oxyalkylene structure in which alkylene oxide is added to a primary organic amine, partial ester compounds of carboxylic acids and polyhydric alcohols, amide compounds in which amine compounds and carboxylic acids are condensed, compounds having a (poly)oxyalkylene structure in which alkylene oxide is added to fatty acid amides, and compounds having a polyoxyalkylene structure such as block copolymers having a polyoxyethylene chain and a polyoxypropylene chain.

[0036] Specific examples of alcohols that can be used as raw materials for the other nonionic surfactants (B3) include, for example, (1) linear alkyl alcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, heneicosanol, docosanol, tricosanol, tetracosanol, pentacosanol, hexacosanol, heptacosanol, octacosanol, nonacosanol, and triacontanol; (2) isopropanol, isobutanol, isohexanol, 2-ethylhexanol, isononanol, isodecanol, isododecanol, isotridecanol, isotetradecanol, and isotriacontanol; Examples of the branched alkyl alcohols include isohexadecanol, isoheptadecanol, isooctadecanol, isonadecanol, isoeicosanol, isoheneicosanol, isodocosanol, isotricosanol, isotetracosanol, isopentacosanol, isohexacosanol, isoheptacosanol, isooctacosanol, isononacosanol, and isopentadecanol; (3) linear alkenyl alcohols such as tetradecenol, hexadecenol, heptadecenol, octadecenol, and nonadecenol; (4) branched alkenyl alcohols such as isohexadecenol and isooctadecenol; (5) cyclic alkyl alcohols such as cyclopentanol and cyclohexanol; and (6) aromatic alcohols such as phenol, nonylphenol, benzyl alcohol, monostyrenated phenol, distyrenated phenol, and tristyrenated phenol.

[0037] Specific examples of carboxylic acids used as raw materials for the other nonionic surfactants (B3) include, for example, (1) linear alkyl carboxylic acids such as octylic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, heneicosanoic acid, and docosanoic acid; (2) branched alkyl carboxylic acids such as 2-ethylhexanoic acid, isododecanoic acid, isotridecanoic acid, isotetradecanoic acid, isohexadecanoic acid, and isooctadecanoic acid; (3) linear alkenyl carboxylic acids such as octadecenoic acid, octadecadienoic acid, and octadecatrienoic acid; (4) aromatic carboxylic acids such as benzoic acid; and (5) hydroxycarboxylic acids such as ricinoleic acid.

[0038] The alkylene oxide used as a raw material for forming the (poly)oxyalkylene structure of the other nonionic surfactant (B3) is preferably an alkylene oxide having 2 to 4 carbon atoms. Specific examples of alkylene oxide include, for example, ethylene oxide, propylene oxide, butylene oxide, etc. The number of moles of alkylene oxide added is appropriately set, but is preferably 0.1 to 60 moles, more preferably 1 to 40 moles. Any combination of the above upper and lower limits is also possible. The number of moles of alkylene oxide added indicates the number of moles of alkylene oxide per mole of the compound to be added in the charged raw material. The alkylene oxide may be one type of alkylene oxide used alone, or two or more types of alkylene oxides may be used in appropriate combination. When two or more types of alkylene oxides are used, the addition form may be any of block addition, random addition, and a combination of block addition and random addition, and is not particularly limited.

[0039] Specific examples of polyhydric alcohols used as raw materials for the other nonionic surfactants (B3) include ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,2-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 2,3-dimethyl-2,3-butanediol, glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, trimethylolpropane, sorbitan, pentaerythritol, and sorbitol.

[0040] Specific examples of the aliphatic amines used as raw materials for the other nonionic surfactants (B3) include methylamine, ethylamine, butylamine, octylamine, laurylamine, octadecylamine, octadecenylamine, and coconut amine.

[0041] Specific examples of fatty acid amides used as raw materials for the other nonionic surfactants (B3) include octyl acid amide, lauric acid amide, palmitic acid amide, stearic acid amide, oleic acid amide, behenic acid amide, and lignoceric acid amide.

[0042] The block copolymer of polyoxyethylene chain and polyoxypropylene chain is not particularly limited as long as it has a polyoxypropylene chain with low hydrophilicity and a polyoxyethylene chain with high hydrophilicity and has a surfactant effect. The number of polyoxyethylene chains and polyoxypropylene chains in the molecule is not particularly limited, and may be, for example, a block copolymer consisting of one polyoxypropylene chain and one polyoxyethylene chain, or a poloxamer surfactant consisting of a polyoxypropylene chain and two polyoxyethylene chains sandwiching it. The number of moles of ethylene oxide added to form the polyoxyethylene chain is not particularly limited, and may be, for example, 5 moles or more and 200 moles or less. The number of moles of propylene oxide added to form the polyoxypropylene chain is not particularly limited, and may be, for example, 5 moles or more and 100 moles or less.

[0043] Specific examples of other nonionic surfactants (B3) include, for example, a compound in which an alkylene oxide is added to tetradecyl alcohol, a compound in which an alkylene oxide is added to dodecyl alcohol, a compound in which an alkylene oxide is added to isotridecyl alcohol, a compound in which an alkylene oxide is added to hydrogenated castor oil, an ester obtained by reacting polyethylene glycol with oleic acid, and sorbitan monooleate.

[0044] These other nonionic surfactants (B3) may be used alone or in appropriate combination of two or more kinds. The lower limit of the content of the nonionic surfactant (B) in the nonvolatile content of the sizing agent is set appropriately, but is preferably 10% by mass or more, more preferably 15% by mass or more. When the content is 10% by mass or more, the stability of the sizing agent can be improved. The upper limit of the content of the nonionic surfactant (B) is set appropriately, but is preferably 90% by mass or less, more preferably 80% by mass or less. When the content is 90% by mass or less, the adhesion between the reinforcing fiber to which the sizing agent is applied and the resin can be improved by increasing the blending amount of the resin (A). Note that ranges in which the above upper and lower limits are arbitrarily combined are also envisioned.

[0045] The lower limit of the content of the (poly)oxyalkylene derivative (B1) in the non-volatile content of the sizing agent is appropriately set, but is preferably 0.5 mass% or more, more preferably 1 mass% or more. When the content is 0.5 mass% or more, the fuzz of the reinforcing fiber to which the sizing agent is applied can be reduced. The upper limit of the content of the (poly)oxyalkylene derivative (B1) is appropriately set, but is preferably 55 mass% or less, more preferably 50 mass% or less. When the content is 55 mass% or less, the fuzz of the reinforcing fiber to which the sizing agent is applied can be reduced. Note that ranges in which the above upper and lower limits are arbitrarily combined are also envisioned.

[0046] The lower limit of the content ratio (B1 / B) of the (poly)oxyalkylene derivative (B1) in the total nonionic surfactant (B) blended in the sizing agent is appropriately set, but is preferably 1 mass% or more, more preferably 5 mass% or more. When the content ratio is 1 mass% or more, the fuzz of the reinforcing fiber to which the sizing agent is applied can be reduced. The upper limit of the content ratio (B1 / B) of the (poly)oxyalkylene derivative (B1) in the total nonionic surfactant (B) blended in the sizing agent is appropriately set, but is preferably 90 mass% or less, more preferably 85 mass% or less. When the content ratio is 90 mass% or less, the fuzz of the reinforcing fiber to which the sizing agent is applied can be reduced. Note that ranges in which the above upper and lower limits are arbitrarily combined are also envisaged.

[0047] The lower limit of the content of the (poly)oxyalkylene derivative (B2) in the non-volatile content of the sizing agent is appropriately set, but is preferably 1 mass% or more, more preferably 2 mass% or more. When the content is 1 mass% or more, the adhesion between the reinforcing fiber to which the sizing agent is applied and the resin can be improved. The upper limit of the content of the (poly)oxyalkylene derivative (B2) is appropriately set, but is preferably 40 mass% or less, more preferably 30 mass% or less. When the content is 40 mass% or less, the adhesion between the reinforcing fiber to which the sizing agent is applied and the resin can be efficiently improved. Note that a range in which the above upper and lower limits are arbitrarily combined is also envisaged.

[0048] According to the sizing agent of the first embodiment, the following effects can be obtained. (1-1) The sizing agent of the first embodiment is configured to contain a resin (A) and a nonionic surfactant (B) containing the above-mentioned (poly)oxyalkylene derivative (B1). Therefore, it is possible to reduce the fluff of the reinforcing fiber to which the sizing agent is applied. In addition, it is possible to improve the adhesion between the reinforcing fiber to which the sizing agent is applied and the resin.

[0049] (1-2) When the sizing agent contains the above-mentioned (poly)oxyalkylene derivative (B2), the adhesion between the reinforcing fiber to which the sizing agent is applied and the resin can be further improved. <Second embodiment> Next, a second embodiment of the reinforcing fiber according to the present invention will be described. The second embodiment has the same configuration as the first embodiment, except for the following description.

[0050] The reinforcing fiber of this embodiment is obtained by attaching the sizing agent of the first embodiment to the reinforcing fiber. There is no particular restriction on the amount of attachment (excluding the solvent), but it is preferable that the sizing agent is attached to the reinforcing fiber in an amount of 0.01 mass% to 10 mass%. By specifying the amount within this numerical range, the adhesion unevenness to the reinforcing fiber can be reduced, and the function of the sizing agent described above can be fully exerted.

[0051] (Reinforced Fiber) The type of reinforcing fiber applied in this embodiment is not particularly limited, and examples thereof include inorganic fibers such as glass fiber, carbon fiber, ceramic fiber, metal fiber, mineral fiber, rock fiber, and slag fiber. Among these, glass fiber and carbon fiber are preferred from the viewpoint of more effectively exerting the effects of the present invention. Examples of the types of carbon fiber include PAN-based carbon fiber obtained from acrylic fiber as a raw material, pitch-based carbon fiber obtained from pitch as a raw material, recycled carbon fiber, polyester fiber, and carbon fibers obtained from polyethylene resin, phenolic resin, cellulose resin, lignin resin, etc. as raw materials.

[0052] To apply the sizing agent of the first embodiment to the reinforcing fiber, a method generally used industrially can be applied. For example, a roller immersion method, a roller contact method, a spray method, a papermaking method, etc. can be mentioned. The reinforcing fiber to which the sizing agent is applied may be subsequently dried using a known method.

[0053] (Fiber reinforced plastic composite materials) The reinforcing fibers to which the sizing agent is attached obtained as described above are mainly used for fiber-reinforced resin composite materials obtained by impregnating the fibers with a matrix resin as a base material. When producing a fiber-reinforced resin composite material, the shape of the reinforcing fibers is not particularly limited, and for example, long fiber, short fiber, nonwoven fabric, and the like can be used.

[0054] The matrix resin is appropriately selected from known resins depending on the purpose, use, etc. of the fiber-reinforced resin composite material. Specific examples of the matrix resin include epoxy resin, vinyl ester resin, polyamide resin, polyolefin resin, polyurethane resin, polycarbonate resin, polyester resin, PEEK resin, fluororesin, phenoxy resin, phenol resin, BMI resin, polyimide resin, polyimide resin precursor, polyethersulfone resin, polyacrylic resin, etc. Specific examples of the polyolefin resin include polypropylene resin, polyethylene, etc.

[0055] The matrix resin may be selected in consideration of the type of resin contained in the sizing agent from the standpoint of improving adhesiveness, improving recyclability, and the like. According to the reinforcing fiber of this embodiment, in addition to the effects of the first embodiment, the following effects can be obtained.

[0056] (2-1) In the reinforcing fiber of this embodiment, a sizing agent containing the resin (A) and the above-mentioned nonionic surfactant (B) is attached to the reinforcing fiber. Therefore, a reinforcing fiber with reduced fuzz can be obtained. This improves the manufacturing characteristics of the reinforcing fiber. In addition, a reinforcing fiber with improved adhesion to the resin can be obtained. Therefore, a fiber-reinforced resin composite material with excellent properties, particularly mechanical properties, can be obtained due to the excellent adhesion between the reinforcing fiber and the matrix resin.

[0057] The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs. The sizing agent of the above embodiment does not preclude the addition of other ingredients such as water or an organic solvent, a smoothing agent, an antioxidant, and a preservative, from the viewpoint of maintaining the performance of the sizing agent and improving the applicability to the reinforcing fibers, within the scope that does not impair the effects of the present invention.

[0058] The fields in which the sizing agent of the above embodiment is applied are not particularly limited. For example, the sizing agent may be applied to carbon fiber composite materials (CFRP) impregnated with matrix resin, as well as concrete reinforcing fibers. EXAMPLES

[0059] In the following, examples will be given to more specifically describe the configuration and effects of the present invention, but the present invention is not limited to these examples. In the following examples and comparative examples, parts means parts by mass, and % means % by mass.

[0060] Test section 1 (preparation of sizing agent) Example 1 The sizing agent of Example 1 was prepared by adding 48 parts of Mitsubishi Chemical Corporation's product name: jER828 (epoxy resin (A1-1)) as the resin (A), 40 parts of a compound (B1-1) in which 5 moles of ethylene oxide (hereinafter referred to as EO) are added to 1 mole of cardanol A as the nonionic surfactant (B), 6 parts of a compound (B2-1) in which 30 moles of EO and 5 moles of propylene oxide (hereinafter referred to as PO) are randomly added to 1 mole of tristyrenated phenol, and 6 parts of a compound (B3-1) in which 10 moles of EO and 5 moles of PO are randomly added to 1 mole of tetradecyl alcohol, to a beaker and mixing them well.

[0061] (Examples 2 to 43, Comparative Examples 1 to 4) Each of the sizing agents of Examples 2 to 43 and Comparative Examples 1 to 4 was prepared in the same manner as in Example 1 using the components shown in Tables 1 and 2.

[0062] The type and content of resin (A) and the type and content of nonionic surfactant (B) in the sizing agent of each example are as shown in the "Resin (A)" and "Nonionic Surfactant (B)" columns of Tables 1 and 2, respectively.

[0063] [Table 1]

[0064] [Table 2] Details of the resin (A) and the nonionic surfactant (B) shown in Tables 1 and 2 are as follows.

[0065] <Resin (A)> The resins used are listed in Table 3 below.

[0066] [Table 3] The content of resin (A) in Tables 1 and 2 indicates the content of the active ingredient in the resin raw material.

[0067] <Nonionic surfactant (B)> ((Poly)oxyalkylene derivative (B1)) B1-1: A compound in which 5 moles of EO are added to 1 mole of cardanol A. B1-2: A compound in which 15 moles of EO are added to 1 mole of cardanol B. B1-3: A compound in which 30 moles of EO are added to 1 mole of Cardanol A. B1-4: A compound in which 45 moles of EO are added to 1 mole of cardanol B. B1-5: A compound obtained by adding 15 moles of PO to 1 mole of cardanol A, and then adding 25 moles of EO to the resulting mixture. B1-6: A compound in which 1 mole of cardanol A is randomly added with 10 moles of EO and 15 moles of PO, and then 1 mole of PO is added. B1-7: A compound in which 20 moles of EO and 20 moles of PO are randomly added to 1 mole of cardanol B. B1-8: A compound in which 300 parts of EO are added to 100 parts of cashew nut shell liquid (the number of moles of EO added per mole of alcohol represented by the above general formula (1) is about 10 moles) *Cardanol A used was LB-7000 (a mixture of 90% cardanol and 10% cardol by mass) manufactured by Tohoku Kako Co., Ltd. The hydrocarbon groups in the side chains of cardanol are 5% by mass of pentadecyl groups with 0 unsaturated bonds, 35% by mass of pentadecenyl groups with 1 unsaturated bond, 20% by mass of pentadecadienyl groups with 2 unsaturated bonds, and 40% by mass of pentadecatrienyl groups with 3 unsaturated bonds. The content of (poly)oxyalkylene derivative (B1) listed in Tables 1 and 2 indicates the content ratio of the compound derived from the above general formula (1).

[0068] Cardanol B was LB-7250 (a mixture of 95% by mass of cardanol and 5% by mass of cardol) manufactured by Tohoku Kako Co., Ltd. The hydrocarbon groups in the side chains of cardanol are 5% by mass of pentadecyl groups with 0 unsaturated bonds, 35% by mass of pentadecenyl groups with 1 unsaturated bond, 20% by mass of pentadecadienyl groups with 2 unsaturated bonds, and 40% by mass of pentadecatrienyl groups with 3 unsaturated bonds. The content of (poly)oxyalkylene derivative (B1) shown in Tables 1 and 2 indicates the content ratio of the compound derived from the above general formula (1).

[0069] The cashew nut shell liquid used was CNSL (a mixture of 82% by mass of cardanol and 18% by mass of cardol in the monomer) manufactured by Tohoku Kako Co., Ltd. The hydrocarbon groups in the side chains of cardanol are 5% by mass of pentadecyl groups with 0 unsaturated bonds, 35% by mass of pentadecenyl groups with 1 unsaturated bond, 20% by mass of pentadecadienyl groups with 2 unsaturated bonds, and 40% by mass of pentadecatrienyl groups with 3 unsaturated bonds. The content of (poly)oxyalkylene derivative (B1) listed in Tables 1 and 2 indicates the content ratio of the compound derived from the above general formula (1).

[0070] ((Poly)oxyalkylene derivative (B2)) B2-1: A compound in which 30 moles of EO and 5 moles of PO are randomly added to 1 mole of tristyrenated phenol. B2-2: A compound in which 30 moles of EO and 6 moles of PO are randomly added to 1 mole of tristyrenated phenol. B2-3: A compound obtained by adding 10 moles of PO to 1 mole of tristyrenated phenol and then adding 30 moles of EO to the resulting mixture. B2-4: A compound in which 27 moles of EO and 3 moles of PO are randomly added to 1 mole of distyrenated phenol. B2-5: A compound in which 27 moles of EO and 4 moles of PO are randomly added to 1 mole of distyrenated phenol. B2-6: A compound obtained by adding 5 moles of PO to 1 mole of tristyrenated phenol and then adding 20 moles of EO. B2-7: A compound in which 10 moles of EO are added to 1 mole of nonylphenol (Other nonionic surfactants (B3)) B3-1: A compound in which 10 moles of EO and 5 moles of PO are randomly added to 1 mole of tetradecyl alcohol. B3-2: A compound in which 10 moles of EO are added to 1 mole of dodecyl alcohol. B3-3: A compound obtained by adding 20 moles of PO to 1 mole of isotridecyl alcohol, and then adding 20 moles of EO to the resulting mixture. B3-4: Compound in which 25 moles of EO are added to 1 mole of hydrogenated castor oil B3-5: Ester obtained by reacting 1 mole of polyethylene glycol (number average molecular weight 600) with 1.5 moles of oleic acid B3-6: Sorbitan monooleate Test Category 2 (Evaluation) (Fluff) The prepared sizing agent of each example was diluted with water to prepare an aqueous solution with a solid content of 2%. This aqueous solution was applied to strand-shaped carbon fiber or glass fiber by a dipping method so that 2% of the non-volatile content was applied, thereby preparing strand-shaped fiber to which the sizing agent of each example was applied.

[0071] Next, five chrome-plated stainless steel rods with a diameter of 2 mm were placed in a zigzag pattern at 15 mm intervals so that the fiber bundle passed over their surfaces while contacting them at a contact angle of 120°. The fiber bundle was placed between the stainless steel rods in a zigzag pattern and a tension of 1 kg was applied. Just before the take-up roll, the fiber bundle was sandwiched between two 10 cm x 10 cm sheets of urethane foam with a load of 1 kg applied, and rubbed for 5 minutes at a speed of 1 m / min. The mass of fluff adhering to the sponge during this time was measured and evaluated according to the following criteria. The results are shown in the "Fluff" column in Tables 1 and 2.

[0072] -Fuzziness evaluation criteria ◎ (Good): Less than 0.10 mg / m ○(Acceptable): 0.10mg / m or more, less than 0.20mg / m ×(Not allowed): 0.20mg / m or more (Adhesiveness) The adhesiveness was evaluated by the stress (interfacial shear strength) measured by the microdroplet method using a commercially available composite interface property evaluation device. Figure 1 shows a schematic diagram of the composite interface property evaluation device 10.

[0073] One fiber was taken out of the fiber bundle prepared for the evaluation, and both ends of this fiber 12 were fixed in a taut state to a plate-like rectangular frame-shaped holder 11 with adhesive 14. Next, epoxy resin (trade name jER828 and triethylenetetramine, manufactured by Mitsubishi Chemical Corporation) was attached to the fiber 12 so as to form resin droplets 13 with a diameter of about 100 μm, and the resin was fixed by heating in an atmosphere of 150° C. for 15 minutes.

[0074] Two plate-like blades 17, 18, each having a tapered vertical cross section on one side, are attached to an apparatus main body (not shown) in a position where their tips 17a and 18a face each other.

[0075] The holder 11 was attached to the substrate 16 fixed to the device body at a position where the fiber 12 to which the resin droplet 13 was fixed was sandwiched between the tips 17a, 18a of the two blades 17, 18. A load cell 15 was connected to the substrate 16, and the load applied to the substrate 16 was measured.

[0076] When the holder 11 was moved in the fiber axis direction at a speed of 5 mm / min, the maximum load F generated when the resin droplet 13 was peeled off from the fiber 12 by the tips 17a, 18a of the blades 17, 18 was measured by the load cell 15.

[0077] Using the measured values, the interfacial shear strength τ was calculated according to the following formula 1. The same procedure was repeated 20 times to calculate the average interfacial shear strength. From the average value, the adhesion was evaluated according to the following criteria. The results are shown in the "Adhesion" column of Tables 1 and 2.

[0078]

number

[0079] Adhesion evaluation ◎ (Good): Interfacial shear strength is 50 MPa or more ○(Acceptable):Interfacial shear strength is 40MPa or more and less than 50MPa × (Not acceptable): Interfacial shear strength is less than 40 MPa From the results in Tables 1 and 2, according to the present invention, it is possible to improve the effect of reducing the fluff of reinforcing fibers to which a sizing agent has been applied, and also to improve the adhesion between the reinforcing fibers to which a sizing agent has been applied and the resin. [Explanation of symbols]

[0080] 10…Composite interface characteristic evaluation device 11…Holder 12…Fiber 13…Resin Droplet 14…Glue 15…Load cell 16...Substrate 17,18…Blade

Claims

1. A sizing agent for reinforcing fibers containing a resin (A) and a nonionic surfactant (B), A sizing agent for reinforcing fibers, characterized in that the nonionic surfactant (B) contains the following (poly)oxyalkylene derivative (B1): (Poly)oxyalkylene derivative (B1): A compound in which at least one alkylene oxide selected from ethylene oxide and propylene oxide is added in a total amount of 1 mol to 100 mol to 1 mol of an alcohol represented by the following general formula (1): 【Chemistry 1】 (In Chemical Formula 1, R １ : a hydrocarbon group having 10 to 20 carbon atoms and one or more double bonds.

2. The sizing agent for reinforcing fibers according to claim 1, wherein the resin (A) contains an epoxy resin (A1).

3. The sizing agent for reinforcing fibers according to claim 1, wherein the content of the (poly)oxyalkylene derivative (B1) in the non-volatile content of the sizing agent for reinforcing fibers is 1 mass% or more and 50 mass% or less.

4. The sizing agent for reinforcing fibers according to claim 1, wherein the nonionic surfactant (B) contains the following (poly)oxyalkylene derivative (B2): (Poly)oxyalkylene derivative (B2): A compound obtained by adding at least one alkylene oxide selected from ethylene oxide and propylene oxide to an aromatic alcohol other than the alcohol represented by the above general formula (1).

5. A reinforcing fiber having the sizing agent for reinforcing fibers according to any one of claims 1 to 4 attached thereto.

6. The reinforcing fiber according to claim 5 , wherein the reinforcing fiber is a carbon fiber or a glass fiber.

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