Sizing agent for reinforcing fibers and use thereof

Abstract

The present application provides a sizing agent which is excellent in high-temperature stability under high concentration conditions, a fiber-reinforced composite material, and a fiber bundle. The present application provides a sizing agent for a reinforcing fiber, which contains a compound (A) and a compound (B) represented by the following general formula (1), the compound (A) containing at least one selected from the group consisting of an aromatic polyester resin (A1) and a compound (A2) having an ethylenic unsaturated group, the aromatic polyester resin (A1) being a polyester resin containing the following structural unit (I) and structural unit (II) as structural units, the ethylenic unsaturated group being at least one selected from the group consisting of a vinyl ester group, an acrylic ester group, and a methacrylic ester group, the compound (A) being contained in the non-volatile component of the sizing agent for the reinforcing fiber in a proportion of 10% by weight or more.

Description

Technical Field

[0001] This invention relates to sizing agents for reinforcing fibers and their uses. Specifically, it relates to sizing agents for reinforcing fibers used to reinforce matrix resins, reinforcing fiber bundles using the sizing agents, and fiber-reinforced composite materials. Background Technology

[0002] Fiber-reinforced composite materials, incorporating various synthetic fibers to reinforce plastic materials (called matrix resins), are widely used in automotive, aerospace, sports and leisure, and general industrial applications. Examples of fibers used in these composites include various inorganic fibers such as carbon fiber, glass fiber, and ceramic fiber, as well as various organic fibers such as aramid fiber, polyamide fiber, and polyethylene fiber. These synthetic fibers are typically manufactured in filament form and then processed into sheet-like intermediate materials called unidirectional prepregs using methods such as hot-melt and roller winding, or processed using filament winding, or, depending on the situation, into fabrics or chopped fiber shapes, and then used as reinforcing fibers after various high-precision processing steps.

[0003] Epoxy resins are widely used as matrix resins for reinforcing fiber composites. Besides epoxy resins, unsaturated polyester resins, vinyl ester resins, and acrylic resins are also used as matrix resins for free radical polymerization systems.

[0004] In order to improve the mechanical strength of reinforced fiber composites, the wettability and adhesion between the matrix resin and the reinforcing fiber become important. For the aforementioned epoxy resin and free radical polymer matrix resin, sizing agents that improve the wettability and adhesion of the reinforcing fiber have been proposed (e.g., Patent Documents 1 and 2).

[0005] However, in the sizing agents described in Patent Documents 1 and 2, it was observed that the properties of the sizing agents, such as wettability and adhesion, decreased over time.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 53-52796

[0009] Patent Document 2: Japanese Patent Application Publication No. 06-173170 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] An investigation was conducted into the reasons for the decline in the performance of sizing agents over time. The results showed that the performance of sizing agents decreases over time at high temperatures. Furthermore, it was determined that when sizing agents are exposed to high temperatures for extended periods due to transportation to high-temperature regions or storage in unavoidable high-temperature environments, they become unstable, leading to deterioration and separation.

[0012] Therefore, the object of the present invention is to provide a sizing agent with excellent high-temperature stability under high concentration conditions, a reinforced fiber bundle using the sizing agent, and a fiber-reinforced composite material.

[0013] Methods for solving problems

[0014] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that the above-mentioned problems can be solved by using a sizing agent for reinforcing fibers containing a specific resin and a specific compound.

[0015] That is, the sizing agent for reinforcing fibers of the present invention contains compound (A) and compound (B) represented by the following general formula (1). The compound (A) contains at least one selected from aromatic polyester resin (A1) and compound (A2) having olefin unsaturated groups. The aromatic polyester resin (A1) is a polyester resin containing the following structural units (I) and (II) as structural units. The olefin unsaturated groups are at least one selected from vinyl ester group, acrylate group and methacrylate group. The compound (A) accounts for 10% by weight or more of the non-volatile components in the sizing agent for reinforcing fibers.

[0016] Structural unit (I): a structural unit formed from at least one selected from isophthalic acid, ester-forming derivatives of isophthalic acid, terephthalic acid, ester-forming derivatives of terephthalic acid, sulfonated isophthalic acid, ester-forming derivatives of sulfonated isophthalic acid and alkali metal salts of sulfonated isophthalic acid.

[0017] Structural unit (II): Structural unit formed from polyalkylene glycol.

[0018] [Chemistry 1]

[0019]

[0020] (In equation (1), R) 1 and R 2 Each atom is independently a hydrogen atom or an alkyl group. AO is an oxoalkylene group having 2 to 4 carbon atoms. m and n are each independently a number of 1 or more.

[0021] The weight ratio (A / B) of the above-mentioned compound (A) and the above-mentioned compound (B) is preferably 0.1 to 9.0.

[0022] The sum of m and n (m+n) is preferably 8 to 60.

[0023] The reinforced fiber bundle of the present invention is formed by attaching the above-mentioned reinforced fibers to the raw material reinforced fiber bundle with a sizing agent.

[0024] The fiber-reinforced composite material of the present invention comprises a matrix resin and the aforementioned reinforcing fiber bundles.

[0025] Invention Effects

[0026] The sizing agent for reinforcing fibers of the present invention exhibits excellent high-temperature stability even at high concentrations. The sizing agent for reinforcing fibers of the present invention can impart excellent bundle properties to the reinforcing fibers, and further imparts excellent adhesion to the matrix resin.

[0027] The reinforcing fiber bundles of the present invention exhibit minimal or no change over time due to the absence of sizing agents, thus suppressing fuzzing and reduced adhesion to the matrix resin even during prolonged storage at high temperatures. By using the reinforcing fiber bundles of the present invention, reinforcing fiber composite materials with excellent physical properties can be obtained. Detailed Implementation

[0028] The components of the sizing agent for reinforcing fibers of the present invention will be described in detail.

[0029] [Compound (A)]

[0030] Compound (A) comprises at least one selected from the aromatic polyester resins (A1) described later and the compound having olefinic unsaturated groups (A2) described later. Compound (A) is a component that contributes to the high-temperature stability of the sizing agent for reinforcing fibers of the present invention at high concentrations when used in combination with compound (B) described later. In addition, it also functions as a component that improves bundle adhesion and cohesion.

[0031] When compound (A) contains an aromatic polyester resin (A1), it is preferred from the perspective of achieving the effects of this application.

[0032] The reason why the sizing agent for reinforcing fibers of the present invention exhibits excellent high-temperature stability even at high concentrations is uncertain. However, it is believed that by using compounds (A) and (B) simultaneously, their compatibility and emulsification are improved, thus resulting in excellent high-temperature stability even at high concentrations. It is also believed that without compound (B), insufficient emulsification is likely to occur, leading to poor high-temperature stability at high concentrations.

[0033] [Aromatic polyester resin (A1)]

[0034] The aromatic polyester resin (A1) is a component that contributes to the high-temperature stability of the sizing agent for reinforcing fibers of the present invention at high concentrations when used in combination with the compound (B) described later. It also functions as a component that improves bundle bonding and adhesion.

[0035] Aromatic polyester resin (A1) is a copolymer of a polycarboxylic acid or its anhydride and a polyol. It is a polymer containing at least one aromatic compound among the aforementioned polycarboxylic acid or its anhydride and the polyol, and is a polymer that does not contain vinyl ester, acrylate, or methacrylate groups within its molecule. There are no particular limitations on the manufacturing method of aromatic polyester resin (A1), and known methods can be used. One or more aromatic polyester resins (A1) can be used.

[0036] Aromatic polyester resin (A1) comprises the following structural units (I) and (II) as structural units.

[0037] Structural unit (I): a structural unit formed from one or more of the following: isophthalic acid, ester-forming derivatives of isophthalic acid, terephthalic acid, ester-forming derivatives of terephthalic acid, sulfonated isophthalic acid, ester-forming derivatives of sulfonated isophthalic acid, and alkali metal salts of sulfonated isophthalic acid.

[0038] Structural unit (II): Structural unit formed from polyalkylene glycol.

[0039] <Structural Unit (I)>

[0040] So-called ester-forming derivatives of isophthalic acid are derivatives of isophthalic acid, and specifically, derivatives that can form isophthalic esters through esterification or transesterification reactions. Specific examples of ester-forming derivatives of isophthalic acid include esters, anhydrides, and amides of isophthalic acid.

[0041] Ester-forming derivatives of terephthalic acid are derivatives of terephthalic acid that can form terephthalic esters through esterification or transesterification. Specific examples of ester-forming derivatives of terephthalic acid include esters, anhydrides, and amides of terephthalic acid.

[0042] So-called ester-forming derivatives of sulfoisophthalic acid are derivatives of sulfoisophthalic acid, and are derivatives that can form sulfoisophthalic acid esters through esterification or transesterification reactions. Specific examples of ester-forming derivatives of sulfoisophthalic acid include esters, anhydrides, and amides of sulfoisophthalic acid.

[0043] Examples of alkali metal salts of sulfoisophthalic acid include sodium 5-sulfoisophthalate, potassium 5-sulfoisophthalate, lithium 5-sulfoisophthalate, sodium 1,3-dimethyl-5-sulfoisophthalate, potassium 1,3-dimethyl-5-sulfoisophthalate, and lithium 1,3-dimethyl-5-sulfoisophthalate.

[0044] The structural unit (I) preferably comprises isophthalic acid and sodium sulfoisophthalate, more preferably formed only of isophthalic acid and sodium sulfoisophthalate.

[0045] <Structural Unit (II)>

[0046] Structural unit (II) is a structural unit formed from polyalkylene glycol.

[0047] Examples of polyalkylene glycols include diethylene glycol, triethylene glycol, dipropylene glycol, dibutylene glycol, and tributylene glycol. Structural unit (II) preferably contains diethylene glycol, and more preferably is formed solely from diethylene glycol.

[0048] There are no limitations on aromatic polyester resins (A1) as long as they contain structural units (I) and (II) as structural units. They may also contain structural units formed by aliphatic dicarboxylic acids as structural units other than structural units (I) and (II).

[0049] When manufacturing aromatic polyester resin (A1), it is sufficient that at least one of the above-mentioned polycarboxylic acid or its anhydride (sometimes referred to as all polycarboxylic acid components) and polyol contains an aromatic compound, wherein preferably 40 to 100 mol% of the all polycarboxylic acid components is an aromatic dicarboxylic acid, more preferably 80 to 99 mol%.

[0050] Furthermore, from the viewpoint of emulsification stability when aromatic polyester resin (A1) is formulated into an aqueous solution, it is preferable that 1 to 10 mol% of the total polycarboxylic acid component is an aromatic dicarboxylic acid containing sulfonate. Therefore, among the polycarboxylic acids and polyols exemplified above, phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyl dicarboxylic acid, diphenoxyethanedicarboxylic acid, phthalic anhydride, sulfoterephthalate, and 5-sulfoisophthalate are preferred as polycarboxylic acids. As for polyols, aliphatic diols are preferred, and ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, 1,4-butanediol, and neopentyl glycol are particularly preferred.

[0051] From the viewpoint of maximizing the effects of this application, the weight-average molecular weight of the aromatic polyester resin (A1) is preferably 3,000 to 100,000, and more preferably 5,000 to 30,000.

[0052] [Compounds containing olefinic unsaturated groups (A2)]

[0053] Compound (A2) having an olefinic unsaturated group (hereinafter sometimes referred to as compound (A2)) is a component that contributes to the high-temperature stability of the reinforcing fiber sizing agent of the present invention at high concentrations by being used in combination with compound (B) described later. It also functions as a component that improves bundle bonding and adhesion.

[0054] Compound (A2) is a compound having at least one group selected from vinyl ester, acrylate, and methacrylate groups. Compound (A2) may use one or more of these groups. It should be noted that the vinyl ester group represents a group represented by "CH2=CHOCO-", the acrylate group represents a group represented by "CH2=CHCOO-", and the methacrylate group represents a group represented by "CH2=CCH3COO-".

[0055] Examples of compounds (A2) include alkyl (meth)acrylates, alkoxy polyalkylene glycol (meth)acrylates, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-hydroxyalkyl (meth)acrylate, dialkylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2-methacryloyloxyethyl 2-hydroxypropyl phthalate, polyalkylene glycol di(meth)acrylate, alkylene glycol di(meth)acrylate, glycerol di(meth)acrylate, 2-hydroxy-3-acryloyloxypropyl (meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, bisphenol A (meth)acrylate, epoxyalkane addition bisphenol A (meth)acrylate, bisphenol A diglycidyl ether (meth)acrylate adduct, and epoxyalkane addition bisphenol A diglycidyl ether (meth)acrylate. Acrylic acid adducts, trimethylolpropane tri(meth)acrylate, glycidyl methacrylate, phenoxyalkyl methacrylate, phenoxypolyalkylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropanol (meth)acrylate, polyalkylene glycol nonylphenyl ether (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl-phthalate, neopentyl glycol (meth)acrylate benzoate, epoxy alkane addition trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, pentaerythritol tri(meth)acrylate hexamethylene diisocyanate urethane prepolymers, etc.

[0056] Among these, compound (A2), considering its excellent adhesion to the matrix resin, preferably contains at least one group selected from alkylene and aryl groups, more preferably containing an aryl group. Specifically, preferably 2-methacryloyloxyethyl 2-hydroxypropyl phthalate, polyalkylene glycol di(meth)acrylate, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl-phthalate, neopentyl glycol (meth)acrylate benzoate, bisphenol A (meth)acrylate, epoxyalkane addition bisphenol A (meth)acrylate, bisphenol A diglycidyl ether (meth)acrylate adduct, epoxyalkane addition bisphenol A diglycidyl ether (meth)acrylate adduct, etc. Acrylic acid adducts, more preferably polyalkylene glycol di(meth)acrylate, bisphenol A (meth)acrylate, epoxy alkane-added bisphenol A (meth)acrylate, bisphenol A diglycidyl ether (meth)acrylate adduct, epoxy alkane-added bisphenol A diglycidyl ether (meth)acrylate adduct, particularly preferably bisphenol A (meth)acrylate, epoxy alkane-added bisphenol A (meth)acrylate, bisphenol A diglycidyl ether (meth)acrylate adduct, epoxy alkane-added bisphenol A diglycidyl ether (meth)acrylate adduct.

[0057] [Compound (B)]

[0058] The compound (B) used in the sizing agent for reinforcing fibers of the present invention is the compound shown in the above general formula (1), and has a structure in which epoxides are added to both ends of the central portion which is composed of a bisphenol-type backbone.

[0059] By combining compound (B) with the aforementioned compound (A) in this way, high-temperature stability at high concentrations can be improved.

[0060] In the above general formula (1), R 1 and R 2 Each atom is independently a hydrogen atom or an alkyl group. The alkyl group preferably has 1 to 2 carbon atoms, more preferably 1. AO is an oxoalkylene group having 2 to 4 carbon atoms, preferably an oxoalkylene group having 2 to 3 carbon atoms (oxoethylene, oxopropylene), more preferably an oxoethylene group having 2 carbon atoms. m and n are each independently a number of 1 or more, preferably 4 to 20, more preferably 4 to 15, and even more preferably 4 to 10. Furthermore, from the viewpoint of further enhancing the effects of the present invention, m and n are preferably numbers satisfying m+n = 8 to 60. m+n is more preferably 8 to 40, even more preferably 8 to 30, particularly preferably 8 to 20, and most preferably 10 to 20.

[0061] From the viewpoint of maximizing the effects of this application, the molecular weight distribution (Mw / Mn) of compound (B) is preferably 1.01 to 1.50, more preferably 1.01 to 1.30, and even more preferably 1.02 to 1.20.

[0062] The molecular weight distribution of compound (B) can be determined using GPC with compound (B) as the test sample. Compound (B) is not a monodisperse compound, but rather a compound with a broad distribution having a given molecular weight distribution, thus exhibiting excellent high-temperature stability at high concentrations. It should be noted that "high concentration" in this specification preferably refers to a concentration of 30% by weight or higher, with the effects of this application exhibiting in the order of greater than 30% by weight, 35% by weight or higher, 40% by weight or higher, 50% by weight or higher, and 60% by weight or higher (the higher the concentration, the greater the effect of this application).

[0063] In compound (B), the amount of alkyl epoxides added to both ends of the central portion consisting of a bisphenol-type skeleton does not need to be consistent on the left and right sides of the central portion. However, since the above-mentioned compound (B) is usually a compound obtained by adding alkyl epoxides to a bisphenol compound, in most cases the amount of alkyl epoxides added to both ends of the central portion consisting of a bisphenol-type skeleton is not significantly different on the left and right sides of the central portion.

[0064] [Alkyne surfactant (C)]

[0065] From the viewpoint of maximizing the effects of this application, the sizing agent for reinforcing fibers of the present invention preferably contains an alkyne surfactant (C). By combining compound (A) and alkyne surfactant (C), it is also possible to reduce surface tension and improve the uniform adhesion to the reinforcing fiber bundles.

[0066] It should be noted that so-called alkyne surfactants refer to compounds that have hydrophilic groups such as alkynyl and hydroxyl groups in their molecular structure. Alkyne surfactants (C) can be used alone or in combination of two or more.

[0067] The alkynyl surfactant (C) is preferably selected from at least one of alkynyl alcohol (C1), alkynyldiol (C2), a compound obtained by adding an epoxide to an alkynyl alcohol (C3), and a compound obtained by adding an epoxide to an alkynyldiol (C4). Among these, the compound obtained by adding an epoxide to an alkynyl alcohol (C3) and the compound obtained by adding an epoxide to an alkynyldiol (C4) are preferred, and the compound obtained by adding an epoxide to an alkynyldiol (C4) is more preferred.

[0068] Alkynes (C1) are compounds that have an alkynyl group and one hydroxyl group in their molecular structure.

[0069] The alkynol (C1) is preferably a compound represented by the following general formula (2).

[0070] Alkyne diol (C2) is a compound that has an alkynyl group and two hydroxyl groups in its molecular structure.

[0071] The acetylenic diol (C2) is preferably a compound represented by the following general formula (3).

[0072] The compound (C3) obtained by the addition of epoxides to alkynols is a compound obtained by the addition of epoxides to the hydroxyl groups of alkynols.

[0073] The compound (C3) obtained by the addition of alkynol to epoxide is preferably the compound shown in the following general formula (4).

[0074] The so-called compound (C4) obtained by adding an epoxide to an alkene glycol is a compound obtained by adding an epoxide to at least one of the hydroxyl groups of an alkene glycol.

[0075] The compound (C4) obtained by the addition of alkynyl diol to an epoxide is preferably a compound represented by the following general formula (5).

[0076] [Chemistry 2]

[0077]

[0078] (In equation (2), R) 3 and R 4 Each is an alkyl group having 1 to 8 carbon atoms.

[0079] [Chemistry 3]

[0080]

[0081] (In equation (3), R) 5 R 6 R 7 and R 8 Each is an alkyl group having 1 to 8 carbon atoms.

[0082] [Chemistry 4]

[0083]

[0084] (In equation (4), R) 3 and R 4 Each is an alkyl group having 1 to 8 carbon atoms. R 9 It consists of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. AO represents an oxoalkylene group having 2 to 4 carbon atoms. p is a number from 1 to 50.

[0085] [Chemistry 5]

[0086]

[0087] (In equation (5), R) 5 R 6 R 7 and R 8 Each is an alkyl group having 1 to 8 carbon atoms. R9 It is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. It should be noted that the multiple R atoms in formula (5) 9 They can be the same or different. AO represents an alkylene group with 2 to 4 carbon atoms. p and q are each independent numbers from 1 to 50.

[0088] In equations (2) and (4), R 3 and R 4 Each alkyl group is independently an alkyl group having 1 to 8 carbon atoms. The alkyl group can be straight-chain or branched. The alkyl group preferably has 1 to 7 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 5 carbon atoms.

[0089] In equations (3) and (5), R 5 R 6 R 7 and R 8 Each alkyl group is independently an alkyl group having 1 to 8 carbon atoms. The alkyl group can be straight-chain or branched. The alkyl group preferably has 1 to 7 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 5 carbon atoms.

[0090] In equations (4) and (5), R 9 Each of the atoms is independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. The alkyl group preferably has 1 to 4 carbon atoms, more preferably 1 to 3 carbon atoms, and even more preferably 1 to 2 carbon atoms.

[0091] In formulas (4) and (5), AO independently represents an oxoalkylene group having 2 to 4 carbon atoms. That is, it represents oxoethylene, oxopropylene, or oxobutylene. Oxoethylene and oxopropylene are preferred as oxoalkylene groups, and oxoethylene is more preferred. (AO) p Or (AO) q The AO can be one type or two or more types. In the case of two or more types, it can be any of the following: block adduct, alternating adduct, or random adduct.

[0092] In formula (4), p is a number from 1 to 50. p is preferably from 1 to 45, more preferably from 1 to 40, and even more preferably from 1 to 35.

[0093] In equation (5), p and q are each independently a number from 1 to 50. Preferably, p and q are each independently a number from 1 to 45, more preferably a number from 1 to 40, and even more preferably a number from 1 to 35.

[0094] From the viewpoint of maximizing the effects of this application, the HLB of the alkyne surfactant (C) is preferably 4 to 25, more preferably 5 to 20, and even more preferably 6 to 18. The HLB of this invention can be experimentally determined using the Atlas method proposed by Griffin et al.

[0095] Alkyne surfactants (C) are known compounds that can be readily manufactured using known methods. For example, such compounds can be obtained by reacting ketones or aldehydes with alkynes under pressure in the presence of catalysts such as bases or metal compounds, in a process known as the Rip reaction.

[0096] In addition, the above-mentioned compounds (C3) or (C4) can be obtained by addition polymerization of alkylene alcohols (C1) or alkylene diols (C2) in the presence of catalysts such as bases or metal compounds to alkylene oxides (C1) or alkylene diols (C2) to alkylene oxides (e.g., ethylene oxide and / or propylene oxide).

[0097] (Resin (D) other than compound (A))

[0098] As a resin (D) other than compound (A), at least one selected from polyurethane resin, epoxy resin, polyamide resin, polyolefin resin and phenolic resin can be cited.

[0099] As a polyurethane resin, there are no particular limitations as long as it is a reaction product with known polyisocyanates and known polyols as the main components.

[0100] As a polyisocyanate, it can be an aromatic polyisocyanate compound or an aliphatic polyisocyanate compound.

[0101] Examples of aromatic polyisocyanate compounds include toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene diisocyanate, naphthalene-1,5-diisocyanate, mono- or dichlorophenylene-2,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 3-methyldiphenylmethane-4,4'-diisocyanate, m-phenylene-diisocyanate, p-phenylene-diisocyanate, and triphenylmethane triisocyanate.

[0102] In addition, examples of aliphatic polyisocyanate compounds include 1,6-hexamethylene diisocyanate, propyl diisocyanate, and butyl diisocyanate. One or more of the polyisocyanate compounds exemplified above may be used as polyisocyanate compounds, either individually or in combination.

[0103] Examples of polyols include polyethylene glycol, polypropylene glycol, ethylene oxide and / or propylene oxide adducts of bisphenol A, polyether polyols, polyester polyols as condensates of polyols with polyacids such as succinic acid, adipic acid, and phthalic acid, polyols having carboxyl or sulfonic acid groups such as 2,2-dimethylolpropionic acid and 1,4-butanediol-2-sulfonic acid, and polyol compounds exemplified as constituent components of polyester resins.

[0104] Epoxy resins are compounds with two or more reactive epoxy groups in their molecular structure. A representative example of an epoxy resin is the glycidyl ether type obtained from epichlorohydrin and an active hydrogen compound. Other examples include glycidyl ester, glycidyl amine, and alicyclic types. An epoxy resin can be a single type or a combination of two or more types.

[0105] As for epoxy resins, there are no particular limitations as long as they contain hydroxyl groups. Examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol linear phenolic epoxy resin, cresol linear phenolic epoxy resin, alkylphenol linear phenolic epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, amine modified aromatic epoxy resin, and various other modified epoxy resins.

[0106] As for polyamide resins, there are no particular limitations as long as the main chain is formed by repeating amide bonds. Examples include polyamide 6 (obtained by ring-opening polymerization of ε-caprolactam), polyamide 66 (obtained by condensation polymerization of hexamethylenediamine and adipic acid), and polyamide resins that are water-soluble by introducing hydrophilic groups into the main chain.

[0107] Examples of polyolefins include homopolymers or copolymers of olefins such as polyethylene, polypropylene, ethylene-propylene copolymers, and poly(methylpentene-1), as well as copolymers of olefins and comonomers (ethylene-vinyl acetate copolymers, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid copolymers, etc.). These polyolefin resins can be used alone or in combination of two or more. Among polyolefin resins are polypropylene resins with a propylene content of 50% by weight or more (especially 75% to 100% by weight), such as polypropylene, propylene-ethylene copolymers, propylene-butene copolymers, and propylene-ethylene-butene copolymers.

[0108] Examples of phenolic resins include those obtained by condensing phenols such as phenol, cresol, xylenol, tert-butylphenol, nonylphenol, cashew nut oil, lignin, resorcinol, and catechol with aldehydes such as formaldehyde, acetaldehyde, and furfural. Examples include linear phenolic resins and methyl phenolic resins. Linear phenolic resins can be obtained by reacting phenol and formaldehyde in equal or excess amounts in the presence of an acid catalyst such as oxalic acid. methyl phenolic resins can be obtained by reacting phenol and formaldehyde in equal or excess amounts in the presence of an alkaline catalyst such as sodium hydroxide, ammonia, or organic amines.

[0109] The sizing agent for reinforcing fibers of the present invention may contain surfactants other than the alkyne surfactant (C) mentioned above (hereinafter referred to as other surfactants).

[0110] Regarding other surfactants, when the sizing agent contains resins that are insoluble or poorly soluble in water, they can be used as emulsifiers to efficiently perform aqueous emulsification.

[0111] As for other surfactants, there are no particular limitations; a known surfactant may be appropriately selected from nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants other than the alkyne surfactants (C) mentioned above. One surfactant or two or more surfactants may be used.

[0112] Examples of nonionic surfactants include alkylene oxide addition nonionic surfactants (surfactants obtained by adding alkylene oxides such as ethylene oxide and propylene oxide to higher alcohols, higher fatty acids, alkylphenols, styrenated phenols, benzylphenols, glycerol, pentaerythritol, sorbitol, sorbitol dehydrated, sorbitol esters, castor oil, hydrogenated castor oil, higher aliphatic amines, fatty acid amides, and oils), surfactants obtained by adding higher fatty acids to polyalkylene glycols, ethylene oxide / propylene oxide copolymers, esters of polyols and fatty acids, and aliphatic alkanolamides.

[0113] More specifically, examples of nonionic surfactants include linear alkyl ethers of polyoxyethylene such as polyoxyethylene hexyl ether, polyoxyethylene octyl ether, polyoxyethylene decyl ether, polyoxyethylene lauryl ether, and polyoxyethylene cetyl ether; branched primary alkyl ethers of polyoxyethylene such as polyoxyethylene 2-ethylhexyl ether, polyoxyethylene isocetyl ether, and polyoxyethylene isostearyl ether; branched secondary alkyl ethers of polyoxyethylene such as polyoxyethylene 1-hexylhexyl ether, polyoxyethylene 1-octylhexyl ether, polyoxyethylene 1-hexyloctyl ether, polyoxyethylene 1-pentylheptyl ether, and polyoxyethylene 1-heptylpentyl ether; and polyoxyethylene... Polyoxyethylene oil-based ethers and other polyoxyethylene alkenyl ethers; polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecylphenyl ether and other polyoxyethylene alkenyl phenyl ethers; polyoxyethylene tristyrene phenyl ether, polyoxyethylene stilbene phenyl ether, polyoxyethylene styrene phenyl ether, polyoxyethylene tristyrene methyl phenyl ether, polyoxyethylene stilbene methyl phenyl ether, polyoxyethylene styrene methyl phenyl ether, polyoxyethylene tribenzyl phenyl ether, polyoxyethylene dibenzyl phenyl ether, polyoxyethylene benzyl phenyl ether and other polyoxyethylene alkenyl ethers. arylphenyl ethers; polyoxyethylene monolaurate, polyoxyethylene monooleate, polyoxyethylene monostearate, polyoxyethylene monomyristate, polyoxyethylene dilaurate, polyoxyethylene dioleate, polyoxyethylene dimyristate, polyoxyethylene distearate, and other polyoxyethylene fatty acid esters; sorbitan monopalmitate, sorbitan monooleate, and other sorbitan esters; polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, and other polyoxyethylene sorbitan fatty acid esters; glyceryl monostearate, glyceryl monostearate, etc. Glyceryl fatty acid esters such as glyceryl monolaurate and glyceryl monopalmitate; polyoxyethylene sorbitan fatty acid esters; sucrose fatty acid esters; polyoxyethylene castor oil ethers such as polyoxyethylene castor oil ether; polyoxyethylene hydrogenated castor oil ethers such as polyoxyethylene hydrogenated castor oil ether; polyoxyethylene alkyl amino ethers such as polyoxyethylene lauryl amino ether and polyoxyethylene stearyl amino ether; ethylene oxide-propylene block or random copolymers; terminal alkyl ethers of ethylene oxide-propylene block or random copolymers; terminal sucrose ethers of ethylene oxide-propylene block or random copolymers; etc.

[0114] Examples of anionic surfactants include carboxylic acid (salts), sulfate salts of higher alcohols / higher alcohol ethers, sulfonates, and phosphate salts of higher alcohols / higher alcohol ethers.

[0115] More specifically, examples of anionic surfactants include fatty acids (salts) such as oleic acid, palmitic acid, sodium oleate, potassium palmitate, and triethanolamine oleate; carboxylic acids (salts) containing hydroxyl groups such as glycolic acid, potassium glycolate, lactic acid, and potassium lactate; polyoxyethylene alkyl ether acetic acids (salts) such as polyoxyethylene tridecyl ether acetic acid (sodium salt); salts of carboxyl-modified aromatic compounds such as potassium trimellitate and potassium pyromellitic acid; alkylbenzene sulfonic acids (salts) such as sodium dodecylbenzene sulfonic acid; polyoxyethylene alkyl ether sulfonic acids (salts) such as potassium 2-ethylhexyl ether sulfonic acid; stearoyl methyl taurate (sodium), lauroyl methyl taurate (sodium), myristoyl methyl taurate (sodium), and palmitoyl methyl taurate (sodium). Higher fatty acid amide sulfonic acids (salts) such as α-carboxylic acid; N-acylcarboxylic acid (salts) such as lauroyl sarcosine (sodium); alkyl phosphonates (potassium salts) such as octylphosphonate; aromatic phosphonates (potassium salts) such as phenylphosphonates; alkyl phosphonates (potassium salts) such as 2-ethylhexyl phosphonate; nitrogen-containing alkyl phosphonates (salts) such as aminoethylphosphonic acid (diethanolamine salt); alkyl sulfates (salts) such as 2-ethylhexyl sulfate (sodium salt); polyoxyethylene sulfates (salts) such as polyoxyethylene 2-ethylhexyl ether sulfate (sodium salt); long-chain sulfosuccinates such as sodium di-2-ethylhexyl sulfosuccinate and sodium dioctyl sulfosuccinate; long-chain N-acyl glutamate salts such as sodium N-lauroyl glutamate and disodium N-stearoyl-L-glutamate; etc.

[0116] Examples of cationic surfactants include lauryltrimethylammonium chloride, myristyltrimethylammonium chloride, palmityltrimethylammonium chloride, stearyltrimethylammonium chloride, oleyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, docosyltrimethylammonium chloride, coconut oil alkyltrimethylammonium chloride, tallow alkyltrimethylammonium chloride, stearyltrimethylammonium bromide, coconut oil alkyltrimethylammonium bromide, hexadecyltrimethylammonium methyl sulfate, oleyldimethylethylammonium ethyl sulfate, dioctyldimethylammonium chloride, dilauryldimethylammonium chloride, distearateldimethylammonium chloride, octadecyldiethylmethylammonium sulfate, and other alkyl quaternary ammonium salts; (polyoxyethylene) laurylamino Ether lactate, stearyl amino ether lactate, di(polyoxyethylene) lauryl methyl amino ether dimethyl phosphate, oleyl methyl ethyl ammonium ethyl sulfate, di(polyoxyethylene) lauryl ethyl ammonium ethyl sulfate, di(polyoxyethylene) hydrogenated tallow alkyl ethyl amino ethyl sulfate, di(polyoxyethylene) lauryl methyl ammonium dimethyl phosphate, di(polyoxyethylene) stearyl amino lactate, etc. (polyoxyethylene) alkyl amino ether salts; N-(2-hydroxyethyl)-N,N-dimethyl-N-stearamidopropyl ammonium nitrate, lanolin fatty acid amide propyl ethyl dimethyl ammonium ethyl sulfate, lauramide ethyl methyl diethyl ammonium methyl sulfate, etc. acylamide alkyl quaternary ammonium salts; dipalmitoyl polyethylene Alkylvinyloxy quaternary ammonium salts such as oxyethyl ammonium chloride and distearate polyvinyloxymethyl ammonium chloride; alkylisoquinoline onion salts such as lauryl isoquinoline onion chloride; benzalkonium salts such as lauryl dimethyl benzyl ammonium chloride and stearyl dimethyl benzyl ammonium chloride; benzyl ammonium salts such as benzyl dimethyl {2-[2-(p-1,1,3,3-tetramethylbutylphenoxy)ethoxy]ethyl} ammonium chloride; pyridinium salts such as hexadecylpyridinium chloride; imidazoline onion salts such as oleyl hydroxyethyl imidazoline onion ethyl sulfate and lauryl hydroxyethyl imidazoline onion ethyl sulfate; acyl basic ammonium salts such as N-cocoyl arginine ethyl ester pyrrolidone carboxylate and N-lauroyl lysine ethyl ester chloride. Alkyl ester salts of basic acids; primary amine salts such as laurylamine chloride, stearylamine bromide, hydrogenated tallow alkylamine chloride, and rosinamine acetate; secondary salts such as hexadecylmethylamine sulfate, laurylmethylamine chloride, dilaurylamine acetate, stearylethylamine bromide, laurylpropylamine acetate, dioctylamine chloride, and octadecylethylamine hydroxide; tertiary amine salts such as dilaurylmethylamine sulfate, lauryl diethylamine chloride, lauryl ethylmethylamine bromide, diethanolstearylamide ethylamine trihydroxyethyl phosphate, and stearylamide ethylethanolamine urea condensate acetate; fatty acid amide guanidine salts; and alkyltriethylene glycol ammonium salts such as lauryl triethylene glycol ammonium hydroxide.

[0117] Examples of amphoteric surfactants include imidazoline-based amphoteric surfactants such as sodium 2-undecyl-N,N-(hydroxyethylcarboxymethyl)-2-imidazoline and 2-cocoyl-2-imidazoline hydroxide-1-carboxyethoxy2-sodium salt; betaine-based amphoteric surfactants such as 2-heptadecyl-N-carboxymethyl-N-hydroxyethylimidazoline betaine, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, lauryl dimethylaminoacetic acid betaine, alkyl betaine, amide betaine, and sulfobetaine; and amino acid-type amphoteric surfactants such as N-lauryl glycine, N-lauryl β-alanine, N-stearyl β-alanine, and sodium lauryl aminopropionate.

[0118] The sizing agent for reinforcing fibers of the present invention may include a smoothing agent (E). Examples of smoothing agents include esters of higher fatty acids and higher alcohols, natural oils (coconut oil, tallow, olive oil, and rapeseed oil, etc.), liquid paraffin, and waxes. Examples of higher fatty acids are described above. Examples of alkyl groups of higher alcohols are described above as alkyl groups constituting hydrophobic groups. Examples of waxes include polyethylene, polypropylene, oxidized polyethylene, modified polyethylene, modified polypropylene, paraffin wax, candelilla wax, carnauba wax, rice bran wax, and beeswax.

[0119] The non-volatile component of the smoothing agent relative to the sizing agent for reinforcing fibers is preferably 0.1 to 20% by weight, more preferably 1 to 10% by weight.

[0120] From the viewpoint of resistance to rubbing and fuzzing, smoothing agents preferably contain fatty acids and / or alcohols with more than 30 carbon atoms, as well as their esters. Examples include candelilla wax and carnauba wax.

[0121] (Sizing agent for reinforcing fibers)

[0122] In the sizing agent for reinforcing fibers of the present invention, compound (A) accounts for 10% or more by weight of the non-volatile components of the sizing agent for reinforcing fibers, preferably 10 to 90% by weight. The upper limit of this weight percentage is more preferably 85% by weight, further preferably 80% by weight, particularly preferably 75% by weight, and most preferably 70% by weight. On the other hand, the lower limit of this weight percentage is more preferably 15% by weight, further preferably 20% by weight, particularly preferably 22% by weight, and most preferably 24% by weight.

[0123] In the sizing agent for reinforcing fibers of the present invention, from the viewpoint of long-term storage stability, the weight ratio (A / B) of the above-mentioned compound (A) and the above-mentioned compound (B) is preferably 0.1 to 9.0. The upper limit of this ratio is more preferably 5.0, further preferably 4.0, particularly preferably 3.0, and most preferably 2.5. On the other hand, the lower limit of this ratio is more preferably 0.5, further preferably 1.0, particularly preferably 1.5, and most preferably 2.0.

[0124] When compound (A) contains an aromatic polyester resin (A1), from the viewpoint of long-term storage stability, the weight ratio (A1 / B) of the aromatic polyester resin (A1) and compound (B) is preferably 0.1 to 9.0. The upper limit of this ratio is more preferably 5.0, further preferably 4.0, particularly preferably 3.0, and most preferably 2.5. On the other hand, the lower limit of this ratio is more preferably 0.5, further preferably 1.0, particularly preferably 1.5, and most preferably 2.0.

[0125] When compound (A) contains compound (A2), from the viewpoint of long-term storage stability, the weight ratio (A2 / B) of the above-mentioned compound (A2) and the above-mentioned compound (B) is preferably 0.1 to 9.0. The upper limit of this ratio is more preferably 5.0, further preferably 4.0, particularly preferably 3.0, and most preferably 2.5. On the other hand, the lower limit of this ratio is more preferably 0.5, further preferably 1.0, particularly preferably 1.5, and most preferably 2.0.

[0126] In the case where the sizing agent for reinforcing fibers of the present invention contains an alkyne surfactant (C), from the viewpoint of long-term storage stability, the weight ratio of the alkyne surfactant (C) to the total weight of the above-mentioned compound (A) and the above-mentioned compound (B) ((C) / (A)+(B)) is preferably 0.001 to 0.15.

[0127] There are no particular limitations on the method for manufacturing the sizing agent of the present invention, and known methods can be used. Examples include: a method of preparing an aqueous solution, emulsion, or aqueous dispersion by adding the components constituting the sizing agent to water under stirring; a method of preparing an aqueous solution, emulsion, or aqueous dispersion when manufacturing the components constituting the sizing agent; a method of adding the components constituting the sizing agent to water containing a surfactant under stirring and emulsifying or dispersing them; a method of mixing the components constituting the sizing agent in an emulsion dispersion that has been pre-emulsified and dispersed; a method of mixing the components constituting the sizing agent and heating the resulting mixture above its softening point, then slowly adding water while applying mechanical shear force using a homogenizer, homogenizer, ball mill, etc., to perform phase inversion emulsification; and a method of mixing an emulsion dispersion that has been emulsified and dispersed with water in an oil bath for applying the sizing agent, etc.

[0128] The sizing agent of the present invention is preferably prepared by self-emulsification and / or emulsification dispersion in water. The average particle size of the sizing agent prepared by self-emulsification and / or emulsification dispersion in water is not particularly limited; however, from the viewpoint of storage stability, it is preferably 10 μm or less, more preferably 0.01 to 1 μm, and even more preferably 0.01 to 0.5 μm. If the average particle size is greater than 10 μm, the sizing agent itself may separate within several days, resulting in poor storage stability and impracticality. It should be noted that the so-called average particle size referred to in the present invention refers to the average value calculated based on the particle size distribution measured using a laser diffraction / scattering particle size distribution measuring device (Horiba LA-920).

[0129] There is no particular limitation on the concentration of the non-volatile component in the sizing agent of the present invention. From the viewpoint of maximizing the excellent high-temperature stability of the present application at high concentrations, the lower limit of the weight percentage of the non-volatile component in the total sizing agent is preferably in the following order: 1) 10% by weight or more, 2) 30% by weight or more, 3) greater than 30% by weight, 4) 35% by weight or more, 5) 40% by weight or more, 6) 50% by weight or more, 7) 60% by weight or more.

[0130] The upper limit of the weight percentage of non-volatile components in the total sizing agent is preferably 100% by weight.

[0131] [Reinforced fiber bundles]

[0132] The reinforcing fiber bundle of the present invention is formed by attaching the above-mentioned reinforcing fiber to the raw material synthetic fiber bundle with a sizing agent, and is a reinforcing fiber used to reinforce thermosetting resin or thermoplastic matrix resin.

[0133] The manufacturing method of the reinforcing fiber bundle of the present invention includes a sizing process in which the aforementioned reinforcing fiber sizing agent is attached to the raw material synthetic fiber bundle and the resulting attached material is dried.

[0134] The method for attaching a sizing agent for reinforcing fibers to the raw synthetic fiber bundle to obtain an attachment is not particularly limited, as long as it utilizes a kissing roller method, roller dipping method, spraying method, or other known methods to attach the sizing agent for reinforcing fibers to the raw synthetic fiber bundle. Among these methods, the roller dipping method is preferred because it allows the sizing agent for reinforcing fibers to adhere evenly to the raw synthetic fiber bundle.

[0135] There are no particular limitations on the drying method for the resulting deposits; for example, heating rollers, hot air, hot plates, etc., can be used for heating and drying.

[0136] It should be noted that when the reinforcing fiber sizing agent of the present invention is applied to the raw material synthetic fiber bundle, all components of the reinforcing fiber sizing agent can be applied after mixing, or the components can be applied separately in two or more stages. Furthermore, without impairing the effects of the present invention, thermosetting resins such as epoxy resin and phenolic resin, and / or thermoplastic resins other than the polymer components of the present invention, such as polyolefin resins, nylon resins, polycarbonate resins, polyester resins, polyacetal resins, ABS resins, phenoxy resins, polymethyl methacrylate resins, polyphenylene sulfide resins, polyetherimide resins, and polyetherketone resins, can be applied to the raw material synthetic fiber bundle.

[0137] The reinforcing fiber bundle of the present invention is used as a reinforcing fiber for composite materials with various thermosetting resins or various thermoplastic resins as the matrix resin. As a form of use, it can be in the form of continuous fiber or in the form of cut to a given length.

[0138] The amount of non-volatile components of the sizing agent for reinforcing fibers adhering to the raw synthetic fiber bundle can be appropriately selected, as long as it is set to the necessary amount to give the synthetic fiber bundle the desired function. The amount of adhesion is preferably 0.1 to 20% by weight relative to the raw synthetic fiber bundle. In the case of a continuous fiber synthetic fiber bundle, the amount of adhesion is more preferably 0.1 to 10% by weight relative to the raw synthetic fiber bundle, and even more preferably 0.5 to 5% by weight. Furthermore, in the case of a bundle cut to a given length, it is more preferably 0.5 to 20% by weight, and even more preferably 1 to 10% by weight.

[0139] If the amount of sizing agent applied to the reinforcing fibers is insufficient, the synthetic fiber bundles will lack cohesion, resulting in poor workability. Conversely, if the amount of sizing agent applied to the reinforcing fibers is excessive, the synthetic fiber bundles will become too rigid, leading to poor resin penetration during compounding, which is therefore not preferable.

[0140] Synthetic fibers that can be used as raw materials for the reinforcing fiber sizing agent of the present invention include various inorganic fibers such as carbon fiber, glass fiber, and ceramic fiber, as well as various organic fibers such as aramid fiber, polyethylene fiber, polyethylene terephthalate fiber, polybutylene terephthalate fiber, polyethylene naphthalate fiber, polyaryl fiber, polyacetal fiber, PBO fiber, polyphenylene sulfide fiber, and polyketone fiber. From the viewpoint of the physical properties of the resulting fiber-reinforced composite material, at least one selected from carbon fiber, aramid fiber, polyethylene fiber, polyethylene terephthalate fiber, polybutylene terephthalate fiber, polyethylene naphthalate fiber, polyaryl fiber, polyacetal fiber, PBO fiber, polyphenylene sulfide fiber, and polyketone fiber is preferred. Carbon fiber is more preferred.

[0141] [Fiber-reinforced composite materials]

[0142] The fiber-reinforced composite material of the present invention comprises a thermosetting matrix resin or a thermoplastic matrix resin and the aforementioned reinforcing fiber bundles. Since the reinforcing fiber bundles are treated with the reinforcing fiber sizing agent of the present invention, the affinity between the reinforcing fiber bundles and the thermoplastic matrix resin becomes good, resulting in a fiber-reinforced composite material with excellent adhesion.

[0143] The fiber-reinforced composite material of the present invention comprises a matrix resin and the aforementioned reinforcing fiber bundles. The reinforcing fiber bundles are treated with the sizing agent of the present invention, the sizing agent adheres uniformly, and the affinity between the reinforcing fiber bundles and the matrix resin becomes good, resulting in a fiber-reinforced composite material with excellent adhesion. Furthermore, the thermal decomposition of the sizing agent during high-temperature treatment can be suppressed, and adhesion obstacles to the matrix resin caused by thermal decomposition can be suppressed. Here, the matrix resin refers to a matrix resin comprising a thermosetting resin or a thermoplastic resin, and may comprise one or more types. As a thermosetting resin, there are no particular limitations, and examples include epoxy resin, phenolic resin, unsaturated polyester resin, vinyl ester resin, cyanate ester resin, polyimide resin, etc. As a thermoplastic resin, there are no particular limitations, and examples include polyolefin resins, polyamide resins, polycarbonate resins, polyester resins, polyacetal resins, ABS resins, phenoxy resins, polymethyl methacrylate resins, polyphenylene sulfide resins, polyetherimide resins, polyetherketone resins, etc. Among them, thermosetting resins are preferred, and epoxy resins and vinyl ester resins are more preferred, considering the greater improvement in adhesion brought about by the sizing agent of the present invention.

[0144] For purposes such as further improving and reinforcing the adhesion of fiber bundles, these matrix resins may be partially or wholly modified resins.

[0145] There are no particular limitations on the manufacturing method of fiber-reinforced composite materials. Known methods such as composite injection molding based on chopped fibers, long fiber particles, compression molding based on UD sheets, fabric sheets, etc., as well as fiber winding molding, can be used.

[0146] There is no particular limitation on the content of synthetic fiber bundles in fiber-reinforced composite materials. It can be appropriately selected according to the type, morphology of the fiber, and the type of thermoplastic matrix resin. However, it is preferred to be 5 to 70% by weight, more preferably 20 to 60% by weight, relative to the resulting fiber-reinforced composite material.

[0147] Example

[0148] The present invention will now be specifically described using examples, but is not limited to the examples described herein. It should be noted that percentages (%) and parts shown in the following examples, unless otherwise specified, refer to "weight %" or "parts by weight". The determination of each characteristic value was performed based on the methods described below.

[0149] The mixture was stirred to obtain the non-volatile component composition shown in the table below, and then diluted with water to prepare a sizing agent with a non-volatile component concentration of 20% by weight. Subsequently, the obtained sizing agent was diluted with water to prepare a sizing agent dilution with a non-volatile component concentration of 3% by weight. It should be noted that the values ​​in the table represent the weight percentage of each component (in the case of an aqueous dispersion, its non-volatile component) in the non-volatile component of the sizing agent.

[0150] Then, untreated carbon fiber bundles (800 tex fineness, 12,000 filaments) were impregnated and infiltrated into the prepared sizing agent dilution using the Dip Nip method, and then dried with hot air at 105°C for 15 minutes to obtain sizing agent-treated carbon fiber bundles. The obtained sizing agent-treated carbon fiber bundles were then used to evaluate their bundle cohesion, adhesion, abrasion resistance, storage stability, and uniform adhesion using the methods shown below.

[0151] <Adhesion rate of the treatment agent>

[0152] Approximately 10g of fiber coated with the sizing agent composition was added to a Soxhlet extractor and extracted with methyl ethyl ketone for 2 hours. The weight difference of the fiber before and after extraction was calculated.

[0153] <Clustering>

[0154] Various sizing agents (diluted with water to 3%, target adhesion rate 1%) were applied to the carbon fiber. The resulting material was then cut into 10 strands, each 5 mm long, using a cutting tool. Whether loosening occurred was visually evaluated. Based on the following evaluation criteria, ◎ and ○ were marked as acceptable.

[0155] ◎: Loosen if there are 2 or fewer roots;

[0156] ○: Loosen 3 to 4 strands;

[0157] △: Loosen 5 to 7 strands;

[0158] ×: Loosen more than 8 pieces.

[0159] <Adhesion>

[0160] The adhesion was evaluated using the HM410 composite material interface property evaluation device (manufactured by Toei Sangyo Co., Ltd.) via the droplet method.

[0161] Carbon fiber filaments were taken from the carbon fiber bundles obtained in the examples and comparative examples and placed in a sample holder. Droplets of each matrix resin were formed on the carbon fiber filaments to obtain a sample for testing. The test sample was placed in the device, and the droplets were held by the device blades. The carbon fiber filaments were moved on the device at a speed of 0.06 mm / min, and the maximum pull-out load F when the droplets were pulled out of the carbon fiber filaments was measured.

[0162] The interfacial shear strength τ was calculated using the following formula, and the adhesion between the carbon fiber filaments and each matrix resin was evaluated. The epoxy resin and vinyl ester resin described below were used as matrix resins. The curing methods for the matrix resins are as follows.

[0163] Interfacial shear strength τ (unit: MPa) = F / πdl

[0164] (F: Maximum pull-out load; d: Carbon fiber filament diameter; l: Droplet diameter in the pull-out direction.)

[0165] <Methods for curing droplets of matrix resin>

[0166] The matrix resins used are epoxy resin and vinyl ester resin.

[0167] Epoxy resin: The matrix resin, which is adjusted to 100 parts by weight of epoxy resin jER828 (manufactured by Mitsubishi Chemical Corporation) and 3 parts by weight of DICY (manufactured by Mitsubishi Chemical Corporation), is heated to 80°C for 1 hour and 150°C for 3 hours to cure.

[0168] Vinyl ester resin: The matrix resin, adjusted to 100 parts by weight of vinyl ester resin RIPOXY R-806 (manufactured by Showa Denko Co., Ltd.) and 2 parts by weight of PERCURE O (manufactured by Nippon Oil Co., Ltd.), was heated to 80°C for 1 hour and 150°C for 3 hours to cure.

[0169] Abrasion resistance

[0170] Using the TM-200 friction cohesion tester (manufactured by Daiei Scientific Instruments Co., Ltd.), the carbon fiber bundles obtained in the examples and comparative examples were rubbed 1000 times with a tension of 50g using three staggered mirror-plated stainless steel needles (reciprocating speed 300 times / minute). The fuzzing state of the carbon fiber bundles was visually judged based on the following criteria, and ◎ and ○ were marked as qualified.

[0171] ◎: Just like before rubbing, no fuzz is visible at all.

[0172] ○: Although a few fine hairs were observed, it was at a level that was perfectly functional.

[0173] △: A lot of fuzzing was observed, and some broken threads were also identified.

[0174] ×: It can be confirmed that there are a lot of fuzz and broken monofilaments.

[0175] High Temperature Stability

[0176] Each sizing agent diluted with water to achieve a non-volatile component concentration of 20% by weight will be stored in a constant temperature bath adjusted to 40°C. The appearance of the solution will be visually confirmed, and the stability of the solution will be judged based on the following evaluation criteria. ◎ and ○ will be marked as qualified.

[0177] ◎: We haven't been separated for 60 days.

[0178] ○: No separation within 30 days, separation within 60 days.

[0179] △: No separation for 7 days, separation within 30 days.

[0180] ×: Separation within 7 days.

[0181] Uniform adhesion

[0182] The uniform adhesion was evaluated using the following felt settling test.

[0183] Nikke S20 (No. 103) woven felt, cut into 2cm x 2cm pieces, was floated in 100mL of a sizing agent diluted with water to 1% of the active ingredient. The time (in seconds) until settling was measured to evaluate uniform adhesion. Temperature: 23℃. A shorter settling time indicates better uniform adhesion.

[0184] The indicators are shown below. Set ◎ and ○ as qualified.

[0185] Excellent (◎): Under 90 seconds;

[0186] Good (○): Greater than 90 seconds and less than 180 seconds;

[0187] Slightly unsatisfactory (△): greater than 180 seconds but less than 300 seconds;

[0188] Bad (×): More than 300 seconds.

[0189] The compounds used in the examples are shown below.

[0190] (A1-1): A copolymer of isophthalic acid, diethylene glycol, and sodium sulfoisophthalate;

[0191] (A1-2): A copolymer of isophthalic acid, terephthalic acid, diethylene glycol, and sodium sulfoisophthalate.

[0192] [Synthesis of Resin (A1)]

[0193] (Synthetic example resin (A1-1))

[0194] Under nitrogen-sealed conditions in the reactor, 950 parts of dimethyl isophthalate, 1000 parts of diethylene glycol, 0.5 parts of zinc acetate, and 0.5 parts of antimony trioxide were added, and a transesterification reaction was carried out at 140–220°C for 3 hours. Then, 30 parts of sodium isophthalate-5-sulfonate were added, and an esterification reaction was carried out at 220–260°C for 1 hour, followed by a polycondensation reaction at 240–270°C under reduced pressure for 2 hours.

[0195] Next, 200 parts of the obtained aromatic polyester resin and 100 parts of ethylene glycol monobutyl ether were added to an emulsifier and stirred at 150-170°C to homogenize them. Then, 700 parts of water were slowly added while stirring to obtain an aromatic polyester resin (A1-1) as an aqueous emulsion with 20% by weight of non-volatile components.

[0196] (Synthetic example resin (A1-2))

[0197] Under nitrogen-sealed conditions in the reactor, 475 parts of dimethyl isophthalate, 475 parts of dimethyl terephthalate, 1000 parts of diethylene glycol, 0.5 parts of zinc acetate, and 0.5 parts of antimony trioxide were added, and a transesterification reaction was carried out at 140–220°C for 3 hours. Then, 30 parts of sodium isophthalate-5-sulfonate were added, and an esterification reaction was carried out at 220–260°C for 1 hour, followed by a polycondensation reaction at 240–270°C under reduced pressure for 2 hours.

[0198] Next, 200 parts of the obtained aromatic polyester resin and 100 parts of ethylene glycol monobutyl ether were added to an emulsifier and stirred at 150-170°C to homogenize them. Then, 700 parts of water were slowly added while stirring to obtain an aromatic polyester resin (A1-2) as an aqueous emulsion with 20% by weight of non-volatile components.

[0199] The ingredients used in the comparative examples are shown below.

[0200] (A′3) An aqueous dispersion of an aliphatic polyester (a copolymer of polyoxyethylene glycol and adipic acid);

[0201] (A′4) An aqueous dispersion of a bisphenol A-based polyester (a copolymer of maleic anhydride and the EO4 molar adduct of bisphenol A).

[0202] (Synthetic Example A′3)

[0203] Under nitrogen-sealed conditions in a reactor, 1.0 mol of polyoxyethylene glycol (10 mol) and 2.0 mol of adipic acid were added, and the mixture underwent a dehydration condensation reaction at 190 °C for 3 hours to obtain the ester compound (A-3). The weight-average molecular weight (Mw) was 2840, and the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) (Mw / Mn) was 1.7.

[0204] Ester compound (A-3), POE (150) hydrogenated castor oil ether, and PO / EO (25 / 75) polyether (molecular weight 16000) were added to an emulsification device. Water was slowly added under stirring and the mixture was allowed to undergo phase inversion emulsification to obtain a sizing agent aqueous dispersion with a non-volatile component concentration of 30% by weight.

[0205] (Synthetic Example A′4)

[0206] Maleic anhydride (0.9 mol) was reacted with bisphenol A (4 mol) ethylene oxide adduct (1.0 mol) at 140 °C for 5 hours to obtain an unsaturated polyester (A-4) with an acid value of 2.5. The weight-average molecular weight (Mw) was 3051, and the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) (Mw / Mn) was 1.6.

[0207] Unsaturated polyester (A-4), POE (150) hydrogenated castor oil ether, and PO / EO (25 / 75) polyether (molecular weight 16000) were added to an emulsification device. Water was slowly added under stirring and the mixture was allowed to undergo phase inversion emulsification to obtain a sizing agent aqueous dispersion with a non-volatile component concentration of 30% by weight.

[0208] [Preparation of an aqueous dispersion of compound (A2)]

[0209] (Manufacturing Example A2-1)

[0210] A composition comprising bisphenol A diglycidyl ether acrylate adduct and 150 mol of ethylene oxide hydrogenated castor oil ether in a weight ratio of 80 / 20 was added to an emulsifying apparatus. Water was slowly added under stirring and the mixture was allowed to undergo phase inversion emulsification to obtain a homogeneous aqueous dispersion A2-1 of the bisphenol A diglycidyl ether acrylate adduct. The non-volatile component of aqueous dispersion A2-1 was 40% by weight.

[0211] The average particle size of the aqueous dispersion A2-1 was measured to be 0.19 μm. Furthermore, even after being placed at 50°C for one month, no aggregation or flotation separation was observed in the aqueous dispersion A2-1, demonstrating excellent static stability.

[0212] (Manufacturing Example A2-2)

[0213] Except that in Manufacturing Example A2-1, 4 mol of ethylene oxide was used to add 4 mol of bisphenol A to acrylate instead of bisphenol A diglycidyl ether acrylate, an aqueous dispersion A2-2 of 4 mol of ethylene oxide added bisphenol A to acrylate was obtained in the same manner as in Manufacturing Example A2-1. The non-volatile component of aqueous dispersion A2-2 was 40% by weight.

[0214] The average particle size of the aqueous dispersion A2-2 was measured to be 0.25 μm. Furthermore, even after being placed at 50°C for one month, no aggregation or flotation separation was observed in the aqueous dispersion A2-2, demonstrating excellent static stability.

[0215] (Manufacturing Example A2-3)

[0216] A composition comprising 150 mol of 2-acryloyloxyethyl-2-hydroxyethyl-phthalate / ethylene oxide addition hydrogenated castor oil ether / oxyethylene-oxypropylene block polymer (weight average molecular weight 15000, oxypropylene / oxyethylene = 20 / 80 (weight ratio)) = 70 / 20 / 10 (weight ratio) was added to an emulsifying apparatus. Water was slowly added under stirring and allowed to undergo phase inversion emulsification to obtain a homogeneous aqueous dispersion A2-3 of 2-acryloyloxyethyl-2-hydroxyethyl-phthalate. The non-volatile component of aqueous dispersion A2-3 was 40% by weight.

[0217] The average particle size of the aqueous dispersion A2-3 was measured to be 0.29 μm. Furthermore, even after being placed at 50°C for one month, no aggregation or flotation separation was observed in the aqueous dispersion A2-3, demonstrating excellent static stability.

[0218] (Manufacturing Example A2-4)

[0219] A composition comprising trimethylolpropane trimethacrylate / ethylene oxide-propylene oxide block polymer (weight average molecular weight 15000, propylene oxide / ethylene oxide = 20 / 80 (weight ratio)) / ethylene oxide-propylene oxide block polymer (weight average molecular weight 2000, propylene oxide / ethylene oxide = 60 / 40 (weight ratio)) = 70 / 15 / 15 (weight ratio) was added to an emulsifying apparatus. Water was slowly added under stirring and the mixture was allowed to undergo phase inversion emulsification to obtain a homogeneous aqueous dispersion of trimethylolpropane trimethacrylate, A2-4. The non-volatile component of aqueous dispersion A2-4 was 40% by weight.

[0220] The average particle size of the aqueous dispersion A2-4 was measured to be 0.21 μm. Furthermore, even after being placed at 50°C for one month, no aggregation or flotation separation was observed in the aqueous dispersion A2-4, demonstrating excellent static stability.

[0221] The ingredients used in the examples or comparative examples are shown below.

[0222] (B1): POE(8) Bisphenol A ether (BA-8glycol: manufactured by Japan Emulsifier Co., Ltd.);

[0223] (B2): POE(10) Bisphenol A ether (BA-10glycol: manufactured by Japan Emulsifier Co., Ltd.);

[0224] (B3): POE(17.5) Bisphenol A ether (Blaunon (registered trademark) BEO-17.5: manufactured by Aoki Oils & Fats Co., Ltd.);

[0225] (B′4)POE stilbene phenyl ether (Emulgen (registered trademark) A-500).

[0226] The ingredients used in the examples or comparative examples are shown below.

[0227] (C1): 20 molar adduct of ethylene oxide from 2,4,7,9-tetramethyl-5-decyn-4,7-diol;

[0228] (C2): 2,4,7,9-Tetramethyl-5-decyn-4,7-diol in ethylene oxide 5 molar adduct;

[0229] (C3): 3,6-Dimethyl-4-octyne-3,6-diol;

[0230] (C4): 2,4,7,9-Tetramethyl-5-decyn-4,7-diol.

[0231] The ingredients used in the examples or comparative examples are shown below.

[0232] (D1): Aqueous dispersion of epoxy resin.

[0233] (Manufacturing Example D1)

[0234] A composition comprising jER1001 (manufactured by Mitsubishi Chemical Corporation, solid bisphenol A type epoxy resin, epoxy equivalent 450-500) / jER828 (manufactured by Mitsubishi Chemical Corporation, liquid bisphenol A type epoxy resin, epoxy equivalent: 184-194) / POE(150) hydrogenated castor oil ether = 40 / 40 / 20 (by weight) was added to an emulsifying apparatus. Water was slowly added under stirring and the mixture was allowed to undergo phase inversion emulsification to obtain an aqueous dispersion (D1) of epoxy resin containing 30% by weight of non-volatile components.

[0235] (E1): A mixed wax emulsion (40%) of oxidized polyethylene wax, beeswax, carnauba wax, and paraffin wax.

[0236] [Table 1]

[0237]

[0238] [Table 2]

[0239]

[0240] [Table 3]

[0241]

[0242] [Table 4]

[0243]

[0244] [Table 5]

[0245]

[0246] As can be clearly seen from Tables 1 to 4, the sizing agent of the embodiments contains compound (A) and compound (B) represented by the above general formula (1). The compound (A) contains at least one selected from a specific aromatic polyester resin (A1) and a specific compound (A2) having an olefinic unsaturated group, and contains a specific amount of compound (A), thus solving the problem of this application.

[0247] In particular, in Examples 15-18, which contain acetylene surfactant (C), the uniform adhesion is especially excellent.

[0248] On the other hand, as shown in Table 5, the problem cannot be solved in cases where compound (B) is not included (Comparative Examples 1, 2, 3, 7, 8), in cases where it is an aromatic surfactant but not compound (B) as shown in general formula (1) (Comparative Example 3), in cases where it is an aliphatic polyester but not an aromatic polyester resin (A1) (Comparative Example 4), and in cases where it is an aromatic polyester resin but the structural units are different (Comparative Examples 5, 6).

[0249] Industrial availability

[0250] Fiber-reinforced composites, which use reinforcing fibers to strengthen the matrix resin, are used in automotive, aerospace, sports and leisure, and general industrial applications. Examples of reinforcing fibers include various inorganic fibers such as carbon fiber, glass fiber, and ceramic fiber, as well as various organic fibers such as aramid fiber, polyamide fiber, and polyethylene fiber.

Claims

1. A sizing agent for reinforcing fibers, comprising compound A and compound B represented by the following general formula (1), Compound A is an aromatic polyester resin A1. The aromatic polyester resin A1 is a polyester resin comprising structural unit I and structural unit II as structural units. The compound A accounts for more than 10% by weight of the non-volatile components in the sizing agent for reinforcing fibers; Structural unit I: a structural unit formed from at least one selected from sulfoisophthalic acid, ester-forming derivatives of sulfoisophthalic acid, and alkali metal salts of sulfoisophthalic acid. Structural unit II: A structural unit formed from polyalkylene glycol. In equation (1), R 1 and R 2 Each is independently a hydrogen atom or an alkyl group; AO is oxyethylidene; m and n are each independently a number greater than 1.

2. The sizing agent for reinforcing fibers according to claim 1, wherein, The weight ratio of compound A to compound B, A / B, is 0.1 to 9.

0.

3. The sizing agent for reinforcing fibers according to claim 1 or 2, wherein, The sum of m and n, m+n, is 8 to 60.

4. A reinforced fiber bundle, which is formed by attaching the reinforced fiber according to any one of claims 1 to 3 to the raw material reinforced fiber bundle with a sizing agent.

5. A fiber-reinforced composite material comprising a matrix resin and the reinforcing fiber bundle of claim 4.

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