KR20240045319A - Sizing agent for reinforcing fiber and its uses - Google Patents

Abstract

We provide sizing agents with excellent high-temperature stability even at high concentrations, reinforced fiber strands and fiber-reinforced composite materials using them. A sizing agent for reinforced fibers containing a compound (A) and a compound (B) represented by the formula (1), wherein the compound (A) is an aromatic polyester resin (A1) and a compound (A2) having an ethylenically unsaturated group. The aromatic polyester resin (A1) is a polyester resin containing structural units (I) and (II) as structural units, and the ethylenically unsaturated group is a vinyl ester group or an acrylic group. A sizing agent for reinforced fibers, which is at least one selected from a rate group and a methacrylate group, and wherein the weight ratio of the compound (A) to the non-volatile content of the sizing agent for reinforced fibers is 10% by weight or more.

Description

Sizing agent for reinforcing fiber and its uses

The present invention relates to a sizing agent for reinforcing fibers and its use. In detail, it relates to sizing agents for reinforcing fibers used to reinforce matrix resins, reinforcing fiber strands using the same, and fiber-reinforced composite materials.

Fiber-reinforced composite materials, in which plastic materials (called matrix resins) are reinforced with various synthetic fibers, are widely used for automotive applications, aviation/space applications, sports/leisure applications, and general industrial applications. Fibers used in these composite materials include various inorganic fibers such as carbon fiber, glass fiber, and ceramic fiber, and various organic fibers such as aramid fiber, polyamide fiber, and polyethylene fiber. Typically, these various synthetic fibers are manufactured into a filament shape and then processed into a sheet-like intermediate material called unidirectional prepreg by a hot melt method or drum winding method, or processed by a filament winding method, or In some cases, it is used as a reinforcing fiber through various advanced processing processes, such as being processed into a fabric or chopped fiber shape.

Epoxy resin is widely used as a matrix resin for reinforced fiber composite materials. In addition to epoxy resins, unsaturated polyester resins, vinyl ester resins, acrylic resins, etc. are used as matrix resins in radical polymerization systems.

In order to improve the mechanical strength of a reinforced fiber composite material, the wettability and adhesion of the matrix resin and the reinforcing fibers are important, and a sizing agent ( For example, patent documents 1 and 2, etc.) have been proposed.

However, the sizing agent disclosed in Patent Document 1 and Patent Document 2 shows a phenomenon in which sizing agent performance, such as wettability and adhesiveness, deteriorates over time.

Patent Document 1: Japanese Patent Application Laid-Open No. 53-52796 Patent Document 2: Japanese Patent Laid-Open No. 06-173170

As a result of investigating the cause of the deterioration of the performance of the sizing agent over time, it was found that the performance of the sizing agent deteriorates over time under high temperatures. Additionally, it has been found that when exposed to high temperatures for a long period of time, such as when transported to a high temperature area or stored in a place where high temperatures are inevitable, the sizing agent becomes unstable, deteriorates, and separates.

Therefore, the purpose of the present invention is to provide a sizing agent with excellent high-temperature stability even at high concentrations, a reinforced fiber strand using the same, and a fiber-reinforced composite material.

As a result of intensive studies to solve the above problems, the present inventors found that the above problems can be solved with a sizing agent for reinforcing fibers containing a specific resin and a specific compound.

That is, the sizing agent for reinforcing fibers of the present invention contains a compound (A) and a compound (B) represented by the following general formula (1), and the compound (A) is an aromatic polyester resin (A1) and an ethylenic It contains at least one type selected from compounds (A2) having an unsaturated group, and the aromatic polyester resin (A1) is a polyester resin containing the following structural units (I) and (II) as structural units, and the ethylene The sexually unsaturated group is at least one selected from a vinyl ester group, an acrylate group, and a methacrylate group, and the weight ratio of the compound (A) to the non-volatile content of the sizing agent for reinforcing fiber is 10% by weight or more.

Constituent unit (I): selected from isophthalic acid, ester-forming derivatives of isophthalic acid, terephthalic acid, ester-forming derivatives of terephthalic acid, sulfoisophthalic acid, ester-forming derivatives of sulfoisophthalic acid and alkali metal salts of sulfoisophthalic acid. A structural unit formed of at least one type.

Constituent unit (II): Constituent unit formed from polyalkylene glycol.

(In formula (1), R ¹ and R ² are each independently a hydrogen atom or an alkyl group. AO is an oxyalkylene group having 2 to 4 carbon atoms. m and n are each independently a number of 1 or more. )

It is preferable that the weight ratio (A/B) of the compound (A) and the compound (B) is 0.1 to 9.0.

It is preferable that the sum (m+n) of m and n is 8 to 60.

The reinforcing fiber strand of the present invention is formed by attaching the sizing agent for reinforcing fiber to the raw reinforcing fiber strand.

The fiber-reinforced composite material of the present invention includes a matrix resin and the reinforcing fiber strand.

The sizing agent for reinforced fiber of the present invention has excellent high temperature stability even at high concentrations. The sizing agent for reinforcing fibers of the present invention can provide excellent binding properties to the reinforcing fibers and also provide excellent adhesion to the matrix resin.

Since the reinforcing fiber strand of the present invention has no or little change in the sizing agent over time, it can suppress the generation of fluff due to abrasion and the decrease in adhesion to the matrix resin even when stored at high temperature for a long period of time. By using the reinforcing fiber strand of the present invention, a reinforcing fiber composite material with excellent physical properties can be obtained.

Each component of the sizing agent for reinforcing fibers of the present invention will be described in detail.

[Compound (A)]

Compound (A) contains at least one type selected from aromatic polyester resin (A1) described later and compound (A2) having an ethylenically unsaturated group described later. Compound (A) is a component that contributes to the high temperature stability at high concentration of the sizing agent for reinforced fiber of the present invention when used in combination with compound (B), which will be described later. In addition, it also functions as a cohesion and adhesion improvement component.

It is preferable that the compound (A) contains an aromatic polyester resin (A1) in that it exhibits the effects of the present application.

The reason why the sizing agent for reinforcing fibers of the present invention has excellent high-temperature stability even at high concentrations is not clear. However, since compound (A) and compound (B) are used simultaneously, they become compatible and emulsibility increases, so high-temperature stability is achieved even at high concentrations. I think it's excellent. When compound (B) is not included, it is thought that emulsibility tends to be insufficient and therefore high temperature stability at high concentrations is poor.

[Aromatic polyester resin (A1)]

The aromatic polyester resin (A1) is a component that contributes to the high temperature stability at high concentration of the sizing agent for reinforced fibers of the present invention when used in combination with the compound (B) described later. In addition, it also functions as a cohesion and adhesion improvement component.

The aromatic polyester resin (A1) is a copolymer of polycarboxylic acid or its anhydride and polyol, and is a polymer in which at least one of the polycarboxylic acid or its anhydride and polyol contains an aromatic compound, and has a vinyl ester group and an acrylic group in the molecule. It is a polymer that does not have a late group or a methacrylate group. The method for producing the aromatic polyester resin (A1) is not particularly limited, and a known method can be adopted. You may use 1 type or 2 or more types of aromatic polyester resin (A1).

The aromatic polyester resin (A1) contains the following structural units (I) and (II) as structural units.

Constituent unit (I): selected from isophthalic acid, ester-forming derivatives of isophthalic acid, terephthalic acid, ester-forming derivatives of terephthalic acid, sulfoisophthalic acid, ester-forming derivatives of sulfoisophthalic acid, alkali metal salts of sulfoisophthalic acid. A structural unit formed by one or two or more units.

Constituent unit (II): Constituent unit formed from polyalkylene glycol.

〈Constitutive unit (I)〉

The ester-forming derivative of isophthalic acid is a derivative of isophthalic acid and is a derivative that can form isophthalic acid ester through an esterification reaction or transesterification reaction. Specific examples of ester-forming derivatives of isophthalic acid include esters, acid anhydrides, and amides of isophthalic acid.

An ester-forming derivative of terephthalic acid is a derivative of terephthalic acid, and is a derivative that can form a terephthalic acid ester through an esterification reaction or transesterification reaction. Specific examples of ester-forming derivatives of terephthalic acid include esters, acid anhydrides, and amides of terephthalic acid.

An ester-forming derivative of sulfoisophthalic acid is a derivative of sulfoisophthalic acid, and is a derivative that can form a sulfoisophthalic acid ester through an esterification reaction or transesterification reaction. Specific examples of ester-forming derivatives of sulfoisophthalic acid include esters, acid anhydrides, and amides of sulfoisophthalic acid.

Alkali metal salts of sulfoisophthalate include sodium 5-sulfoisophthalate, potassium 5-sulfoisophthalate, lithium 5-sulfoisophthalate, and sodium 1,3-dimethyl-5-sulfoisophthalate. salt, 1,3-dimethyl-5-sulfoisophthalic acid potassium salt, and 1,3-dimethyl-5-sulfoisophthalic acid lithium salt.

It is preferable that the structural unit (I) contains isophthalic acid and sodium salt of sulfoisophthalic acid, and more preferably, it consists only of isophthalic acid and sodium salt of sulfoisophthalic acid.

〈Constitutive unit (II)〉

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

Examples of polyalkylene glycol include diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, dibutylene glycol, and tributylene glycol. It is preferable that structural unit (II) contains diethylene glycol, and it is more preferable that it consists only of diethylene glycol.

The aromatic polyester resin (A1) is not limited as long as it contains structural units (I) and (II) as structural units, but is formed of aliphatic dicarboxylic acid as structural units other than structural units (I) and (II). Units may be included.

In producing the aromatic polyester resin (A1), at least one of the polycarboxylic acid or its anhydride (also referred to as the total polycarboxylic acid component) and the polyol may contain an aromatic compound. It is preferable that 100 mol% is aromatic dicarboxylic acid, and it is more preferable that it is 80 to 99 mol%.

Additionally, from the viewpoint of emulsion stability when using the aromatic polyester resin (A1) as an aqueous solution, it is preferable that 1 to 10 mol% of the total polycarboxylic acid component is a sulfonate-containing aromatic dicarboxylic acid. Therefore, among the polycarboxylic acids and polyols exemplified above, polycarboxylic acids include phthalic acid, terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, and diphenoxy acid. Ethane dicarboxylic acid, phthalic anhydride, sulfoterephthalate, and 5-sulfoisophthalate are preferable, and as the polyol, aliphatic diol is preferable, and ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, tetramethylene glycol, and neoglycol are preferred. Pentyl glycol is particularly preferred.

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 from the viewpoint of exhibiting the effects of the present application.

[Compound (A2) having an ethylenically unsaturated group]

Compound (A2) having an ethylenically unsaturated group (hereinafter sometimes referred to as compound (A2)) is used in combination with compound (B), which will be described later, to improve the high temperature stability at high concentration of the sizing agent for reinforced fiber of the present invention. It is a contributing ingredient. In addition, it also functions as a cohesion and adhesion improvement component.

Compound (A2) is a compound having at least one type selected from a vinyl ester group, an acrylate group, and a methacrylate group. Compound (A2) may be used singly or in combination of two or more. Meanwhile, the vinyl ester group represents the group represented by "CH2=CHOCO-", the acrylate group represents the group represented by "CH2=CHCOO-", and the methacrylate group represents the group represented by "CH2=CCH3COO-".

Compound (A2) includes, for example, alkyl (meth)acrylic acid ester, alkoxy polyalkylene glycol (meth)acrylic acid ester, benzyl (meth)acrylic acid ester, phenoxy ethyl (meth)acrylate, and 2-hydroxy alkyl (meth)acrylic acid ester. ) Acrylic acid ester, dialkyl aminoethyl (meth)acrylic acid ester, glycidyl (meth)acrylate, 2-methacryloyloxyethyl 2-hydroxypropyl phthalate, polyalkylene glycol di(meth)acrylate, alkane Diol di(meth)acrylate, glycerin di(meth)acrylate, 2-hydroxy-3-acryloyloxy propyl(meth)acrylate, dimethylol-tricyclodecane di(meth)acrylate, bisphenol A ( Meth)acrylic acid ester, alkylene oxide added bisphenol A (meth)acrylic acid ester, bisphenol A diglycidyl ether (meth)acrylic acid adduct, alkylene oxide added bisphenol A diglycidyl ether (meth)acrylic acid adduct, trimethyl Allpropane tri(meth)acrylate, glycidyl(meth)acrylate, phenoxy alkyl(meth)acrylic acid ester, phenoxy polyalkylene glycol(meth)acrylic acid ester, 2-hydroxy-3 phenoxy propanol (meth) ) Acrylic acid ester, polyalkylene glycol nonylphenyl ether (meth)acrylic acid ester, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl phthalic acid, 2-(meth)acryloyloxy Ethyl-2-hydroxyethyl-phthalic acid, neopentyl glycol (meth)acrylic acid benzoic acid ester, alkylene oxide addition trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylic acid ester, pentaerythritol tetra(meth)acrylate ) Acrylic acid ester, dipentaerythritol hexa(meth)acrylic acid ester, pentaerythritol tri(meth)acrylate hexamethylene diisocyanate urethane prepolymer, etc.

Among these, the compound (A2) preferably has at least one selected from an oxyalkylene group and an aryl group because it has excellent adhesion to the matrix resin, and it is more preferable that it contains an aryl group. Specifically, 2-methacryloyloxyethyl 2-hydroxypropyl phthalate, polyalkylene glycol di(meth)acrylate, 2-(meth)acryloyloxyethyl phthalic acid, 2-(meth)acryloyl. Oxyethyl-2-hydroxyethyl-phthalic acid, neopentyl glycol (meth)acrylic acid benzoic acid ester, bisphenol A (meth)acrylic acid ester, alkylene oxide added bisphenol A (meth)acrylic acid ester, bisphenol A diglycidyl ether (meth) ) Acrylic acid adduct, alkylene oxide added bisphenol A diglycidyl ether (meth)acrylic acid adduct is preferred, polyalkylene glycol di(meth)acrylate, bisphenol A(meth)acrylic acid ester, alkylene oxide added bisphenol A(meth)acrylic acid ester, bisphenol A diglycidyl ether(meth)acrylic acid adduct, and alkylene oxide-adducted bisphenol A diglycidyl ether(meth)acrylic acid adduct are more preferred, and bisphenol A(meth)acrylic acid ester is more preferred. , alkylene oxide added bisphenol A (meth)acrylic acid ester, bisphenol A diglycidyl ether (meth)acrylic acid adduct, and alkylene oxide added bisphenol A diglycidyl ether (meth)acrylic acid adduct are particularly preferred.

[Compound (B)]

Compound (B) used in the sizing agent for reinforcing fibers of the present invention is represented by the above general formula (1), and has a structure in which alkylene oxide is added to both ends of a central portion composed of a bisphenol-type skeleton.

In this way, by using compound (B) in combination with the above-mentioned compound (A), high temperature stability at high concentration can be improved.

In the above formula (1), R ¹ and R ² are each independently a hydrogen atom or an alkyl group. The number of carbon atoms in the alkyl group is preferably 1 to 2, and more preferably 1. AO is an oxyalkylene group having 2 to 4 carbon atoms, preferably an oxyalkylene group (oxyethylene group, oxypropylene group) having 2 to 3 carbon atoms, and more preferably an oxyethylene 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 still more preferably 4 to 10. In addition, in order to further demonstrate the effect of the present invention, it is preferable that m and n are numbers satisfying m+n=8 to 60. As for m+n, 8-40 is more preferable, 8-30 are still more preferable, 8-20 are especially preferable, and 10-20 are most preferable.

From the viewpoint of exhibiting the effects of the present application, the compound (B) preferably has a molecular weight distribution (Mw/Mn) of 1.01 to 1.50, more preferably 1.01 to 1.30, and still more preferably 1.02 to 1.20.

The molecular weight distribution of compound (B) is determined by GPC method using compound (B) as a test sample. Compound (B) is not monodisperse, but is in a broad state with a predetermined molecular weight distribution, thereby providing excellent high-temperature stability even at high concentrations. Meanwhile, high concentration in the present specification preferably means a concentration of 30% by weight or more, in the order of more than 30% by weight, more than 35% by weight, more than 40% by weight, more than 50% by weight, and more than 60% by weight. (The higher the concentration, the more effective it is.)

In compound (B), the amount of alkylene oxide added to both ends of the center consisting of a bisphenol-type skeleton does not need to be the same on the left and right sides of the center, but the compound (B) is generally an alkylene oxide added to the bisphenol compound. Since it is obtained by adding oxide, the amount of alkylene oxide added to both ends of the center consisting of a bisphenol-type skeleton is often not very different from the amount on the left and right of the center.

[Acetylene-based surfactant (C)]

The sizing agent for reinforcing fibers of the present invention preferably contains an acetylene-based surfactant (C) from the viewpoint of exhibiting the effects of the present invention. By using the compound (A) and the acetylenic surfactant (C) together, there is also the effect of lowering the surface tension and improving uniform adhesion to the reinforcing fiber bundle.

On the other hand, acetylene-based surfactant refers to a compound that has hydrophilic groups such as acetylene group and hydroxyl group in its molecular structure. Acetylene-based surfactant (C) may be used individually or in combination of two or more types.

Acetylene-based surfactant (C) is selected from acetylene alcohol (C1), acetylene diol (C2), compound (C3) obtained by adding alkylene oxide to acetylene alcohol, and compound (C4) obtained by adding alkylene oxide to acetylene diol. It is preferable that at least one type is selected. Among these, compound (C3) obtained by adding alkylene oxide to acetylene alcohol and compound (C4) obtained by adding alkylene oxide to acetylene diol are preferable, and compound (C4) obtained by adding alkylene oxide to acetylene diol is more preferable. do.

Acetylene alcohol (C1) is a compound that has an acetylene group and one hydroxyl group in its molecular structure.

Acetylene alcohol (C1) is preferably a compound represented by the following general formula (2).

Acetylene diol (C2) is a compound that has an acetylene group and two hydroxyl groups in its molecular structure.

Acetylene diol (C2) is preferably a compound represented by the following general formula (3).

Compound (C3) obtained by adding alkylene oxide to acetylene alcohol is a compound obtained by adding alkylene oxide to the hydroxyl group of acetylene alcohol.

Compound (C3) obtained by adding alkylene oxide to acetylene alcohol is preferably a compound represented by the following formula (4).

Compound (C4) obtained by adding alkylene oxide to acetylene diol is a compound obtained by adding alkylene oxide to at least one hydroxyl group of acetylene diol.

Compound (C4) obtained by adding alkylene oxide to acetylene diol is preferably a compound represented by the following general formula (5).

(In formula (2), R ³ and R ⁴ are each independently an alkyl group having 1 to 8 carbon atoms.)

(In formula (3), R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently an alkyl group having 1 to 8 carbon atoms.)

(In formula (4), R ³ and R ⁴ are each independently an alkyl group having 1 to 8 carbon atoms. R ⁹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. AO is an oxy alkylene group having 2 to 4 carbon atoms. Indicates that p is a number from 1 to 50.)

(In formula (5), R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently an alkyl group having 1 to 8 carbon atoms. R ⁹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Meanwhile, formula (5 ) A plurality of R ⁹ may be the same or different. AO represents an oxyalkylene group having 2 to 4 carbon atoms. p and q are each independently a number from 1 to 50.)

In formulas (2) and (4), R ³ and R ⁴ are each independently an alkyl group having 1 to 8 carbon atoms. The alkyl group may be straight chain or may have a branched structure. The carbon number of the alkyl group is preferably 1 to 7, more preferably 1 to 6, and still more preferably 1 to 5.

In formulas (3) and (5), R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently an alkyl group having 1 to 8 carbon atoms. The alkyl group may be straight chain or may have a branched structure. The carbon number of the alkyl group is preferably 1 to 7, more preferably 1 to 6, and still more preferably 1 to 5.

In formulas (4) and (5), R ⁹ each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. The carbon number of the alkyl group is preferably 1 to 4, more preferably 1 to 3, and still more preferably 1 to 2.

In formulas (4) and (5), AO each independently represents an oxyalkylene group having 2 to 4 carbon atoms. That is, it represents an oxyethylene group, oxypropylene group, or oxybutylene group. As an oxyalkylene group, an oxyethylene group and an oxypropylene group are preferable, and an oxyethylene group is more preferable. There may be one type of AO constituting (AO) _p or (AO) _q , and two or more types may be used. In the case of two or more types, it may be any of block adducts, alternate adducts, or random adducts.

In formula (4), p is a number from 1 to 50. As for p, 1-45 are preferable, 1-40 are more preferable, and 1-35 are still more preferable.

In equation (5), p and q are each independently numbers from 1 to 50. p and q are each independently preferably 1 to 45, more preferably 1 to 40, and still more preferably 1 to 35.

The HLB of the acetylene-based surfactant (C) is preferably 4 to 25, more preferably 5 to 20, and still more preferably 6 to 18 from the viewpoint of exhibiting the effects of the present application. HLB in the present invention can be experimentally determined using the atlas method proposed by Griffin et al.

Acetylene-based surfactant (C) is a known compound and can be easily produced by a known method. For example, such compounds can be obtained by a method called the Reppe reaction, in which acetylene is reacted with a ketone or aldehyde under pressure in the presence of a catalyst such as an alkali or a metal compound.

In addition, the compound (C3) or compound (C4) is an alkali or metal compound in which alkylene oxide (e.g., ethylene oxide and/or propylene oxide) is added to acetylene alcohol (C1) or acetylene diol (C2), respectively. It can be obtained by addition polymerization in the presence of a catalyst.

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

Resin (D) other than compound (A) includes at least one selected from the group consisting of polyurethane resin, epoxy resin, polyamide resin, polyolefin resin, and phenol resin.

The polyurethane resin is not particularly limited as long as it is a reaction product containing a known polyisocyanate and a known polyol as main components.

The polyisocyanate may be an aromatic polyisocyanate compound or an aliphatic polyisocyanate compound.

Aromatic polyisocyanate compounds include, for example, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, xylene diisocyanate, naphthylene-1,5-diisocyanate, mono- or dichlorophenylene. -2,4-diisocyanate, diphenyl methane-4,4'-diisocyanate, 3,3'-dimethyl diphenyl methane-4,4'-diisocyanate, 3-methyl diphenyl methane-4,4'- Diisocyanate, metaphenylene-diisocyanate, paraphenylene-diisocyanate, triphenylmethane triisocyanate, etc. are mentioned.

Additionally, examples of aliphatic polyisocyanate compounds include 1,6-hexamethylene-diisocyanate, propyl diisocyanate, and butyl diisocyanate. As a polyisocyanate compound, you may use the polyisocyanate compounds illustrated above 1 type or in combination of 2 or more types.

Examples of polyols include polyether polyols such as polyethylene glycol, polypropylene glycol, ethylene oxide and/or propylene oxide adducts of bisphenol A, and polyester polyols which are condensates of polyols and polybasic acids such as succinic acid, adipic acid, and phthalic acid. , polyols having a carboxyl group or sulfonic acid group such as 2,2-dimethylol propionic acid, 1,4-butanediol-2-sulfonic acid, and polyol compounds exemplified as constituents of polyester resins.

An epoxy resin is a compound that has two or more reactive epoxy groups in its molecular structure. Representative epoxy resins include the glycidyl ether type obtained from epichlorohydrin and an active hydrogen compound, and other examples include glycidyl ester type, glycidyl amine type, and alicyclic type. One type of epoxy resin may be used, or two or more types may be used in combination.

The epoxy resin is not particularly limited as long as it has a hydroxyl group, but examples include bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, bisphenol S-type epoxy resin, phenol novolak-type epoxy resin, cresol novolak-type epoxy resin, and alkyl epoxy resin. Various modified epoxy resins such as phenol novolak-type epoxy resin, biphenyl-type epoxy resin, dicyclopentadiene-type epoxy resin, naphthalene-type epoxy resin, and amine-modified aromatic epoxy resin can be mentioned.

The polyamide resin is not particularly limited as long as it is a resin that forms the main chain by repeating amide bonds, and examples include polyamide 6 (via ring-opening polymerization of ε-caprolactam) and polyamide 66 (a combination of hexamethylenediamine and adipic acid). (by condensation polymerization), and polyamide resins made water-soluble by introducing a hydrophilic group into the main chain.

Polyolefins include, for example, polyethylene, polypropylene, ethylene-propylene copolymer, poly(methylpentene-1) and other olefins alone or copolymers, and copolymers of olefins and copolymerizable monomers (ethylene-vinyl acetate copolymer, ethylene -(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, etc.). These polyolefin resins can be used individually or in combination of two or more types. Polyolefin-based resins include polypropylene-based resins having a propylene content of 50% by weight or more (particularly 75 to 100% by weight), such as polypropylene, propylene-ethylene copolymer, propylene-butene copolymer, and propylene-ethylene-butene. Includes copolymers, etc.

Phenolic resins include, for example, phenols such as phenol, cresol, xylenol, t-butyl phenol, nonyl phenol, cashew oil, lignin, resorcin, and catechol. , resins obtained by condensation of aldehydes such as formaldehyde, acetaldehyde, and furfural, and examples include novolac resins and resol resins. Novolac resin can be obtained by reacting phenol and formaldehyde in the presence of an acid catalyst such as oxalic acid in equal amounts or under conditions with an excess of phenol. A resol resin can be obtained by reacting phenol and formaldehyde in the presence of a base catalyst such as sodium hydroxide, ammonia, or an organic amine in equal amounts or under conditions with an excess of formaldehyde.

The sizing agent for reinforcing fibers of the present invention may contain surfactants other than the acetylene-based surfactant (C) (hereinafter simply referred to as other surfactants).

Other surfactants can efficiently perform water-based emulsification by using them as emulsifiers when the sizing agent contains a water-insoluble or poorly soluble resin.

Other surfactants are not particularly limited, and known surfactants other than the above-mentioned acetylenic surfactant (C) can be appropriately selected and used from nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. . Surfactants may be used alone or in combination of two or more types.

Nonionic surfactants include, for example, alkylene oxide addition nonionic surfactants (higher alcohols, higher fatty acids, alkyl phenols, styrenated phenols, benzyl phenol, glycerin, pentaerythritol, sorbitol, sorbitan, sorbitan esters, Castor oil, hydrogenated castor oil, higher aliphatic amines, fatty acid amides, alkylene oxides such as ethylene oxide and propylene oxide (two or more types can be used in combination) added to fats and oils), and higher fatty acids added to polyalkylene glycol. , ethylene oxide/propylene oxide copolymer, ester of polyhydric alcohol and fatty acid, aliphatic alkanol amide, etc.

More specifically, nonionic surfactants include polyoxyalkylene straight-chain alkyl such as polyoxyethylene hexyl ether, polyoxyethylene octyl ether, polyoxyethylene decyl ether, polyoxyethylene lauryl ether, and polyoxyethylene cetyl ether. ether; polyoxy alkylene branched primary alkyl ethers such as polyoxy ethylene 2-ethyl hexyl ether, polyoxy ethylene isocetyl ether, and polyoxy ethylene isostearyl ether; Polyoxy alkylene such as polyoxy ethylene 1-hexyl hexyl ether, polyoxy ethylene 1-octyl hexyl ether, polyoxy ethylene 1-hexyl octyl ether, polyoxy ethylene 1-pentyl heptyl ether, polyoxy ethylene 1-heptyl pentyl ether, etc. branched secondary alkyl ether; polyoxy alkylene alkenyl ethers such as polyoxy ethylene oleyl ether; polyoxy alkylene alkyl phenyl ethers such as polyoxy ethylene octyl phenyl ether, polyoxy ethylene nonyl phenyl ether, and polyoxy ethylene dodecyl phenyl ether; Polyoxyethylene tristyrylphenyl ether, polyoxyethylene distyrylphenyl ether, polyoxyethylene styrylphenyl ether, polyoxyethylene tristyrylmethyl phenyl ether, polyoxyethylene distyrylmethyl phenyl ether, polyoxyethylene styrylmethyl polyoxyalkylene alkyl aryl phenyl ethers such as phenyl ether, polyoxyethylene tribenzyl phenyl ether, polyoxyethylene dibenzyl phenyl ether, and polyoxyethylene benzyl phenyl ether; Polyoxy ethylene monolaurate, polyoxy ethylene monooleate, polyoxy ethylene monostearate, polyoxy ethylene monomyristylate, polyoxy ethylene dilaurate, polyoxy ethylene dioleate, polyoxy ethylene dimyristylate, polyoxy alkylene fatty acid esters such as polyoxy ethylene distearate; Sorbitan esters such as sorbitan monopalmitate and sorbitan monooleate; polyoxy alkylene sorbitan fatty acid esters such as polyoxy ethylene sorbitan monostearate and polyoxy ethylene sorbitan monooleate; Glycerol fatty acid esters such as glycerol monostearate, glycerol monolaurate, and glycerol monopalmitate; polyoxy alkylene sorbitol fatty acid ester; Sucrose fatty acid ester; polyoxy alkylene castor oil ethers such as polyoxy ethylene castor oil ether; polyoxy alkylene hydrogenated castor oil ethers such as polyoxy ethylene hydrogenated castor oil ether; polyoxy alkylene alkyl amino ethers such as polyoxy ethylene lauryl amino ether and polyoxy ethylene stearyl amino ether; oxyethylene-oxypropylene block or random copolymers; terminal alkyl ethers of oxyethylene-oxypropylene block or random copolymers; sucrose terminal etherifications of oxyethylene-oxypropylene block or random copolymers; etc. can be mentioned.

Examples of anionic surfactants include carboxylic acids (salts), sulfuric acid ester salts of higher alcohols and higher alcohol ethers, sulfonates, and phosphoric acid ester salts of higher alcohols and higher alcohol ethers.

More specifically, the anionic surfactant includes fatty acids (salts) such as oleic acid, palmitic acid, sodium salt of oleic acid, potassium salt of palmitic acid, and triethanolamine salt of oleic acid; hydroxyl group-containing carboxylic acids (salts) such as hydroxy acetic acid, hydroxy acetic acid potassium salt, lactic acid, and lactic acid potassium salt; polyoxy alkylene alkyl ether acetic acid (salt) such as polyoxy ethylene tridecyl ether acetic acid (sodium salt); Salts of polysubstituted aromatic compounds with carboxyl groups, such as potassium trimellitate and potassium pyromellitate; Alkyl benzene sulfonic acid (salt) such as dodecyl benzene sulfonic acid (sodium salt); polyoxy alkylene alkyl ether sulfonic acids (salts) such as polyoxy ethylene 2-ethyl hexyl ether sulfonic acid (potassium salt); Higher fatty acid amide sulfonic acids (salts) such as stearoyl methyltaurine (sodium), lauroyl methyltaurine (sodium), myristoyl methyltaurine (sodium), and palmitoyl methyltaurine (sodium); N-acyl sarcosic acid (salt) such as lauroyl sarcosic acid (sodium); Alkyl phosphonic acids (salts) such as octyl phosphonate (potassium salt); Aromatic phosphonic acids (salts) such as phenyl phosphonate (potassium salt); Alkyl phosphonic acids (salts) such as 2-ethylhexyl phosphonate (potassium salt); Nitrogen-containing alkyl phosphonic acids (salts) such as amino ethyl phosphonic acid (diethanol amine salt); Alkyl sulfuric acid esters (salts) such as 2-ethyl hexyl sulfate (sodium salt); Polyoxy alkylene sulfuric acid esters (salts) such as polyoxy ethylene 2-ethyl hexyl ether sulfate (sodium salt); Long-chain sulfosuccinates such as sodium di-2-ethylhexyl sulfosuccinate and sodium dioctyl sulfosuccinate, long-chain N-acyl glutamates such as sodium N-lauroyl glutamate and disodium N-stearoyl-L-glutamate ; etc. can be mentioned.

Cationic surfactants include, for example, lauryl trimethyl ammonium chloride, myristyl trimethyl ammonium chloride, palmityl trimethyl ammonium chloride, stearyl trimethyl ammonium chloride, oleyl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride, behenyl trimethyl ammonium chloride. , palm oil alkyl trimethyl ammonium chloride, tallow alkyl trimethyl ammonium chloride, stearyl trimethyl ammonium bromide, palm oil alkyl trimethyl ammonium bromide, cetyl trimethyl ammonium methosulfate, oleyl dimethyl ethyl ammonium ethosulfate, dioctyl dimethyl ammonium chloride, dilauryl. Alkyl quaternary ammonium salts such as dimethyl ammonium chloride, distearyl dimethyl ammonium chloride, and octadecyl diethyl methyl ammonium sulfate; (Polyoxyethylene)lauryl amino ether lactate, stearyl amino ether lactate, di(polyoxyethylene)lauryl methyl amino ether dimethyl phosphate, oleyl methyl ethyl ammonium ethosulfate, di(polyoxyethylene)lauryl ethyl (polyoxy alkylene) such as ammonium ethosulfate, di(polyoxyethylene)cured tallow alkyl ethyl amine ethosulfate, di(polyoxyethylene)lauryl methyl ammonium dimethyl phosphate, di(polyoxyethylene)stearyl amine lactate, etc. Alkylamino ether salt; N-(2-hydroxy ethyl)-N,N-dimethyl-N-stearoyl amide propyl ammonium nitrate, lanolin fatty acid amide propyl ethyl dimethyl ammonium ethosulfate, lauroyl amide ethyl methyl diethylammonium methosulfate, etc. Acyl amide alkyl quaternary ammonium salt; Alkylethenoxy quaternary ammonium salts such as dipalmityl polyethenoxy ethyl ammonium chloride and distearyl polyethenoxy methyl ammonium chloride; Alkyl isoquinolinium salts such as lauryl isoquinolinium chloride; Benzalkonium salts such as lauryl dimethyl benzyl ammonium chloride and stearyl dimethyl benzyl ammonium chloride; Benzethonium salts such as benzyl dimethyl{2-[2-(p-1,1,3,3-tetramethylbutyl phenoxy)ethoxy]ethyl}ammonium chloride; Pyridinium salts such as cetyl pyridinium chloride; imidazolinium salts such as oleyl hydroxyethylimidazolinium ethosulfate and lauryl hydroxyethylimidazolinium ethosulfate; Acyl basic amino acid alkyl ester salts such as N-cocoyl arginine ethyl ester pyrrolidone carboxylate and N-lauroyl lysine ethyl ethyl ester chloride; primary amine salts such as lauryl amine chloride, stearyl amine bromide, hardened tallow alkyl amine chloride, and rosin amine acetate; secondary amine salts such as cetyl methyl amine sulfate, lauryl methyl amine chloride, dilauryl amine acetate, stearyl ethylamine bromide, lauryl propyl amine acetate, dioctyl amine chloride, and octadecyl ethylamine hydroxide; Tertiary products such as dilauryl methyl amine sulfate, lauryl diethyl amine chloride, lauryl ethyl methyl amine bromide, diethanol stearyl amide ethylamine trihydroxy ethyl phosphate salt, stearyl amide ethyl ethanol amine urea polycondensate acetate, etc. Amine salt; fatty acid amide guanidinium salt; and alkyl trialkylene glycol ammonium salts such as lauryl triethylene glycol ammonium hydroxide.

Amphoteric surfactants include, for example, 2-undecyl-N,N-(hydroxyethyl carboxymethyl)-2-imidazoline sodium, 2-cocoyl-2-imidazolinium hydroxide-1- imidazoline-based amphoteric surfactants such as carboxy ethyloxy disodium salt; 2-Heptadecyl-N-carboxymethyl-N-hydroxy ethyl imidazolium betaine, stearyl dimethyl betaine, lauryl dihydroxy ethyl betaine, lauryl dimethyl amino acetic acid betaine, alkyl betaine, amide betaine Betaine-based amphoteric surfactants such as phosphorus and sulfobetaine; and amino acid-type amphoteric surfactants such as N-lauryl glycine, N-lauryl beta-alanine, N-stearyl beta-alanine, and sodium lauryl amino propionate.

The sizing agent for reinforcing fibers of the present invention may contain a leveling agent E. Examples of the leveling agent include esters of higher fatty acids and higher alcohols, natural fats and oils (palm oil, tallow, olive oil, and rapeseed oil, etc.), liquid paraffin, and wax. Examples of higher fatty acids are as described above. Examples of the alkyl group of the higher alcohol are as described above as the alkyl group constituting the hydrophobic group. Examples of the wax include polyethylene, polypropylene, polyethylene oxide, polypropylene oxide, modified polyethylene, modified polypropylene, paraffin wax, cantellilla wax, carnauba wax, rice bran wax, and beeswax.

The leveling agent is preferably 0.1 to 20% by weight, more preferably 1 to 10% by weight, based on the non-volatile content of the sizing agent for reinforcing fibers.

Among the leveling agents, those containing fatty acids and/or alcohols having 30 or more carbon atoms and esterified products thereof are preferred from the viewpoint of preventing fluffing due to abrasion. Examples include cantellilla wax and carnauba wax.

[Sizing agent for reinforced fiber]

In the sizing agent for reinforcing fibers of the present invention, the weight ratio of compound (A) to the non-volatile content of the sizing agent for reinforcing fibers is 10% by weight or more, preferably 10 to 90% by weight. The upper limit of the weight ratio is more preferably 85 weight%, more preferably 80 weight%, particularly preferably 75 weight%, and most preferably 70 weight%. Meanwhile, the lower limit of the weight ratio is more preferably 15% by weight, more preferably 20% by weight, particularly preferably 22% by weight, and most preferably 24% by weight.

From the viewpoint of long-term storage stability, the sizing agent for reinforced fiber of the present invention preferably has a weight ratio (A/B) of the compound (A) and the compound (B) of 0.1 to 9.0. As for the upper limit of this ratio, 5.0 is more preferable, 4.0 is more preferable, 3.0 is especially preferable, and 2.5 is most preferable. On the other hand, the lower limit of the ratio is more preferably 0.5, more preferably 1.0, especially preferably 1.5, and most preferably 2.0.

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

When compound (A) contains compound (A2), from the viewpoint of long-term storage stability, the weight ratio (A2/B) of compound (A2) and compound (B) is preferably 0.1 to 9.0. As for the upper limit of this ratio, 5.0 is more preferable, 4.0 is more preferable, 3.0 is especially preferable, and 2.5 is most preferable. On the other hand, the lower limit of the ratio is more preferably 0.5, more preferably 1.0, especially preferably 1.5, and most preferably 2.0.

When the sizing agent for reinforcing fibers of the present invention contains an acetylenic surfactant (C), from the viewpoint of long-term storage stability, the acetylenic surfactant (C) relative to the sum of the compound (A) and the compound (B) It is preferable that the weight ratio ((C)/(A)+(B)) is 0.001 to 0.15.

The method for producing the sizing agent of the present invention is not particularly limited, and known methods can be adopted. A method of adding each component of the sizing agent into water while stirring to form an aqueous solution, emulsion, or aqueous product; a method of preparing each component of the sizing agent into an aqueous solution, emulsion, or aqueous product; A method of emulsifying or dispersing each component constituting the sizing agent by adding it under stirring, a method of mixing each component constituting the sizing agent with an emulsion dispersion in which each component constituting the sizing agent has been emulsified and dispersed in advance, and mixing each component constituting the sizing agent to obtain the obtained product. A method of emulsifying the mixture by heating it above the softening point and then slowly adding water while applying mechanical shear force using a homogenizer, homomixer, ball mill, etc., emulsifying in an oil bath where a sizing agent is applied. A method of mixing the dispersed emulsion dispersion and water may be mentioned.

The sizing agent of the present invention is preferably self-emulsifying and/or emulsifyingly dispersed in water. The average particle diameter when the sizing agent is self-emulsifying and/or emulsifyingly dispersed in water is not particularly limited, but is preferably 10 μm or less, more preferably 0.01 to 1 μm, and 0.01 to 0.5 μm from the viewpoint of storage stability. is more preferable. If the average particle diameter is more than 10 μm, the sizing agent itself may separate in a few days, and storage stability may be poor, making it impractical. Meanwhile, the average particle size referred to in the present invention refers to the average value calculated from the particle size distribution measured with a laser diffraction/scattering type particle size distribution measuring device (LA-920 manufactured by Horiba).

There is no particular limitation on the concentration of non-volatile components of the sizing agent of the present invention. From the viewpoint of demonstrating the effect of the present application, which is excellent high temperature stability at high concentrations, the lower limit of the weight ratio of the non-volatile content in the entire sizing agent is preferably in the following order. 1) 10% by weight or more, 2) 30% by weight or more, 3) more 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.

The upper limit of the weight percentage of non-volatile matter in the entire sizing agent is preferably 100% by weight.

[Reinforced fiber strand]

The reinforcing fiber strand of the present invention is obtained by attaching the sizing agent for reinforcing fiber to a raw synthetic fiber strand, and is a reinforcing fiber for reinforcing a thermosetting resin or thermoplastic matrix resin.

The manufacturing method of the reinforcing fiber strand of the present invention is a manufacturing method including a sizing treatment step of attaching the above-described sizing agent for reinforcing fiber to the raw synthetic fiber strand and drying the obtained adhesion.

The method of attaching the sizing agent for reinforcing fiber to the raw synthetic fiber strand to obtain an attachment is not particularly limited, but the sizing agent for reinforcing fiber can be synthesized as a raw material by a kiss roller method, roller dipping method, spray method, or other known methods. Any method of attaching it to a fiber strand is sufficient. Among these methods, the roller dipping method is preferable because it can uniformly adhere the sizing agent for reinforcing fiber to the raw synthetic fiber strand.

There is no particular limitation on the drying method of the obtained deposit, and for example, it can be dried by heating using a heating roller, hot air, or a hot plate.

On the other hand, when attaching the sizing agent for reinforced fibers of the present invention to the raw synthetic fiber strand, all the components of the sizing agent for reinforced fibers may be mixed and then attached, or the components may be attached separately in two or more steps. do. In addition, to the extent that the effect of the present invention is not impaired, thermosetting resins such as epoxy resins and phenol resins and/or polyolefin resins other than the polymer components of the present invention, nylon resins, polycarbonate resins, polyester resins, and polyacetal resins , thermoplastic resins such as ABS resin, phenoxy resin, polymethyl methacrylate resin, polyphenylene sulfide resin, polyether imide resin, and polyether ketone resin may be attached to the raw synthetic fiber strand.

The reinforcing fiber strand of the present invention is used as a reinforcing fiber for composite materials containing various thermosetting resins or various thermoplastic resins as matrix resins, and may be used as a continuous fiber or cut to a predetermined length.

The amount of non-volatile content of the sizing agent for reinforcing fibers adhering to the raw synthetic fiber strand can be appropriately selected, and may be the amount necessary for the synthetic fiber strand to have the desired function. However, the adhesion amount is 0.1 to 20% by weight relative to the raw synthetic fiber strand. It is desirable to be For synthetic fiber strands in a continuous fiber state, the adhesion amount is more preferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight, based on the raw synthetic fiber strand. Moreover, in the strand cut to a predetermined length, 0.5 to 20% by weight is more preferable, and 1 to 10% by weight is more preferable.

If the amount of sizing agent for reinforcing fibers adhered is small, the cohesion of the synthetic fiber strands may be insufficient, which may result in poor handling. Additionally, if the amount of the sizing agent for reinforcing fibers applied is too large, the synthetic fiber strand becomes too stiff, which is not desirable, as the resin impregnation property deteriorates during composite molding.

Synthetic fibers of the (raw material) synthetic fiber strand to which the sizing agent for reinforcing fiber of the present invention can be applied include various inorganic fibers such as carbon fiber, glass fiber, and ceramic fiber, aramid fiber, polyethylene fiber, polyethylene terephthalate fiber, Various organic fibers such as polybutylene terephthalate fiber, polyethylene naphthalate fiber, polyarylate fiber, polyacetal fiber, PBO fiber, polyphenylene sulfide fiber, and polyketone fiber can be mentioned. In terms of physical properties as a fiber-reinforced composite material obtained, carbon fiber, aramid fiber, polyethylene fiber, polyethylene terephthalate fiber, polybutylene terephthalate fiber, polyethylene naphthalate fiber, polyarylate fiber, polyacetal fiber, PBO fiber, poly At least one selected from phenylene sulfide fibers and polyketone fibers is preferred. More preferably, it is carbon fiber.

[Fiber reinforced composite material]

The fiber-reinforced composite material of the present invention contains a thermosetting matrix resin or a thermoplastic matrix resin and the above-described reinforcing fiber strand. Since the reinforcing fiber strand is treated with the sizing agent for reinforcing fiber of the present invention, the affinity between the reinforcing fiber strand and the thermoplastic matrix resin becomes good, resulting in a fiber-reinforced composite material with excellent adhesiveness.

The fiber-reinforced composite material of the present invention contains a matrix resin and the above-described reinforcing fiber strand. The reinforcing fiber strand is treated with the sizing agent of the present invention, and the sizing agent adheres uniformly, resulting in good affinity between the reinforcing fiber strand and the matrix resin, resulting in a fiber-reinforced composite material with excellent adhesiveness. In addition, thermal decomposition of the sizing agent during high temperature treatment can be suppressed, and inhibition of adhesion to the matrix resin due to thermal decomposition can be suppressed. Here, the matrix resin refers to a matrix resin made of a thermosetting resin or a thermoplastic resin, and may be included one type or two or more types. There is no particular limitation on the thermosetting resin, and examples include epoxy resin, phenol resin, unsaturated polyester resin, vinyl ester resin, cyanate ester resin, and polyimide resin. The thermoplastic resin is not particularly limited and includes polyolefin resin, polyamide resin, polycarbonate resin, polyester resin, polyacetal resin, ABS resin, phenoxy resin, polymethyl methacrylate resin, and polyphenylene sulfide resin. , polyether imide resin, polyether ketone resin, etc. Among these, thermosetting resins are preferable, and epoxy resins and vinyl ester resins are more preferable in that the adhesion improvement effect of the sizing agent of the present invention is higher.

These matrix resins may be partially or entirely modified for the purpose of further improving adhesion to the reinforcing fiber strands.

The manufacturing method of fiber-reinforced composite materials is not particularly limited and includes compound injection molding using chopped fibers, long fiber pellets, etc., press molding using UD (unidirectional) sheets, fabric sheets, etc., and other filament winding moldings. Known methods may be adopted.

The content of synthetic fiber strands in the fiber-reinforced composite material is not particularly limited, and may be appropriately selected depending on the type and shape of the fiber, the type of thermoplastic matrix resin, etc., but 5 to 70% by weight is preferable for the resulting fiber-reinforced composite material. , 20 to 60% by weight is more preferable.

《Example》

Hereinafter, the present invention will be described in detail with reference to examples, but it is not limited to the examples described herein. Meanwhile, percentages (%) and parts shown in the examples below indicate 'weight%' and 'parts by weight', unless otherwise specified. Measurement of each characteristic value was performed based on the method shown below.

It was mixed and stirred to obtain the non-volatile content composition shown in the table below, and diluted with water to adjust the sizing agent to have a non-volatile content concentration of 20% by weight. Additionally, the obtained sizing agent was diluted with water to prepare a sizing agent dilution solution with a non-volatile content concentration of 3% by weight. Meanwhile, the values in the table represent the weight ratio of each component (in the case of an aqueous dispersion, the non-volatile content) in the non-volatile content of the sizing agent.

Subsequently, the sizing agent-untreated carbon fiber strand (fineness 800 tex, number of filaments 12,000) is immersed and impregnated in the prepared sizing agent diluent by the Dip Nip method, and then hot air dried at 105°C for 15 minutes to produce sizing agent-treated carbon fiber. Got a strand. Using the obtained sizing agent-treated carbon fiber strand, cohesion, adhesiveness, abrasion resistance, storage stability, and uniform adhesion were evaluated by the methods shown below.

＜Treatment agent adhesion rate＞

Approximately 10 g of fiber to which the sizing agent composition was added was placed in a Soxhlet extractor, extracted with methyl ethyl ketone for 2 hours, and the weight difference of the fiber before and after extraction was calculated.

＜Solidarity＞

Each sizing agent (diluted to 3% with water, target adhesion rate of 1%) was sized on carbon fiber and visually evaluated whether it would loosen when cut into 10 pieces of 5 mm in length with a cutter knife. Judging by the following evaluation standards, ◎ and ○ were considered passing.

◎: 2 or less are loosened.

○: 3 to 4 pieces are loose.

△: 5 to 7 pieces are loose.

×: 8 or more are solved.

＜Adhesiveness＞

Adhesion was evaluated by the microdroplet method using a composite material interface property evaluation device HM410 (Toei Sankyo product).

Carbon fiber filaments are taken out from the carbon fiber strands obtained in Examples and Comparative Examples and set in a sample holder. A drop of each matrix resin was formed on a carbon fiber filament to obtain a sample for measurement. The measurement sample was set in the device, the drop was picked up by the device blade, the carbon fiber filament was run on the device at a speed of 0.06 mm/min, and the maximum pulling load F when the drop was pulled out from the carbon fiber filament was measured.

The interfacial shear strength τ was calculated using the following equation, and the adhesion between the carbon fiber filament and each matrix resin was evaluated. As the matrix resin, the following epoxy resin and vinyl ester resin were used. The method of curing the matrix resin is described later.

Interfacial shear strength τ (unit: MPa) = F/dl

(F: maximum pulling load, d: carbon fiber filament diameter, l: particle size in the pulling direction of the drop)

<Method for curing drops of matrix resin>

The matrix resin used was epoxy resin and vinyl ester resin.

Epoxy resin: A drop of matrix resin adjusted to 100 parts by weight of epoxy resin jER828 (manufactured by Mitsubishi Chemical) and 3 parts by weight of DICY (manufactured by Mitsubishi Chemical) was cured by heating at 80°C for 1 hour and 150°C for 3 hours.

Vinyl ester resin: drop of matrix resin adjusted to 100 parts by weight of vinyl ester resin Lipoxy R-806 (manufactured by Showa Denko) and 2 parts by weight of PERCURE-O (manufactured by NOF Corporation) at 80°C x 1 hour, 150°C x 3. It was cured by heating over time.

＜Abrasion resistance＞

Using a TM-type friction bonding force tester TM-200 (Daiei Kagaku Seiki MFG product), the carbon fiber strands obtained in Examples and Comparative Examples were tested 1,000 times at a tension of 50 g through three mirror-surface chrome-plated stainless steel needles arranged in a zigzag manner. After scraping (reciprocating speed of 300 times/min), the fluff condition of the carbon fiber strand was visually judged based on the following criteria, and ◎ and ○ were judged as passing.

◎: Like before abrasion, no fluff was observed.

○: A few fluffs were visible, but in practical terms it was no problem at all.

△: A lot of fluff was seen, and some strand breaks were also confirmed.

×: Very many fluffs and single yarn breaks were confirmed.

＜High temperature stability＞

Each sizing agent dilution solution diluted with water so that the non-volatile content concentration is 20% by weight is stored in a constant temperature bath adjusted to 40°C, the appearance of the solution is visually checked, and the solution stability is judged using the following evaluation criteria, and ◎ and ○ are indicated. I passed it.

◎: No separation for 60 days.

○: No separation for 30 days, separation within 60 days.

△: No separation for 7 days, separation within 30 days.

×: Separated within 7 days.

＜Uniform adhesion＞

Evaluation of uniform adhesion was performed by the following felt sedimentation test.

Nikke's woven felt S20 (No. 103) cut into 2cm was measured and evaluated for uniform adhesion. Temperature: 23℃. The shorter the time until settling, the better the uniform adhesion.

The indicators are as follows, and ◎ and ○ were considered passing.

Very good (◎): 90 seconds or less

Good (○): More than 90 seconds but less than 180 seconds

Slightly bad (△): More than 180 seconds but less than 300 seconds

Defective (×): Exceeding 300 seconds

The compounds used in the examples are as follows.

(A1-1): Copolymer of isophthalic acid, diethylene glycol, and sulfoisophthalic acid sodium salt

(A1-2): Copolymer of isophthalic acid, terephthalic acid, diethylene glycol, and sulfoisophthalic acid sodium salt

[Synthesis of Resin (A1)]

(Synthetic Resin (A1-1))

After nitrogen gas was sealed in the reactor, 950 parts of dimethyl isophthalate, 1,000 parts of diethylene glycol, 0.5 parts of zinc acetate, and 0.5 parts of antimony trioxide were added, and a transesterification reaction was performed at 140 to 220°C for 3 hours. Next, 30 parts of 5-sulfoisophthalic acid sodium salt was added, and an esterification reaction was performed at 220 to 260°C for 1 hour, followed by a polycondensation reaction at 240 to 270°C under reduced pressure for 2 hours.

Subsequently, 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 to 170°C to homogenize. Subsequently, 700 parts of water was gradually added while stirring to obtain an aromatic polyester resin (A1-1), which is an aqueous emulsifier with a non-volatile content of 20% by weight.

(Synthetic Resin (A1-2))

After nitrogen gas was sealed in the reactor, 475 parts of dimethyl isophthalate, 475 parts of dimethyl terephthalate, 1,000 parts of diethylene glycol, 0.5 parts of zinc acetate, and 0.5 parts of antimony trioxide were added, and transesterification reaction was carried out at 140-220°C for 3 hours. carried out. Next, 30 parts of 5-sulfoisophthalic acid sodium salt was added, and an esterification reaction was performed at 220 to 260°C for 1 hour, followed by a polycondensation reaction at 240 to 270°C under reduced pressure for 2 hours.

Subsequently, 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 to 170°C to homogenize. Subsequently, 700 parts of water was gradually added while stirring to obtain an aromatic polyester resin (A1-2), which is an aqueous emulsifier with a non-volatile content of 20% by weight.

The ingredients used in the comparative example are as follows.

(A-3) Aqueous dispersion of aliphatic polyester (copolymer of polyoxyethylene glycol and adipic acid)

(A-4) Aqueous dispersion of bisphenol A polyester (copolymer of 4 mole EO adduct of maleic anhydride and bisphenol A)

(Synthesis Example (A-3))

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

Ester compound (A-3), POE (150) hydrogenated castor oil ether, and PO/EO (25/75) polyether (molecular weight 16,000) were put into an emulsifier, and water was gradually added while stirring to emulsify the phase. An aqueous dispersion of the sizing agent with a volatile matter concentration of 30% by weight was obtained.

(Synthesis Example (A-4))

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

Unsaturated polyester (A-4), POE (150) hydrogenated castor oil ether, and PO/EO (25/75) polyether (molecular weight 16,000) are put into an emulsifier, and water is gradually added while stirring to emulsify the phase. An aqueous dispersion of the sizing agent with a non-volatile content of 30% by weight was obtained.

[Preparation of aqueous dispersion of Compound (A2)]

(Production Example (A2-1))

A composition consisting of bisphenol A diglycidyl ether acrylic acid adduct/ethylene oxide 150 mol addition hardened castor oil ether = 80/20 (weight ratio) is placed in an emulsifier, and water is gradually added while stirring to invert phase emulsification to achieve uniform dispersion. An aqueous dispersion of bisphenol A diglycidyl ether acrylic acid adduct (A2-1) was obtained. The non-volatile content of the water dispersion (A2-1) was 40% by weight.

The average particle diameter of the water dispersion (A2-1) was measured and found to be 0.19 μm. In addition, the aqueous dispersion (A2-1) showed no coagulation or flotation separation even when left at 50°C for 1 month, and had excellent static stability.

(Production Example (A2-2))

In Preparation Example (A2-1), except that 4 mol of ethylene oxide added bisphenol A acrylic acid was used instead of the bisphenol A diglycidyl ether acrylic acid adduct, 4 mol of ethylene oxide added bisphenol was prepared in the same manner as in Preparation Example (A2-1). A water dispersion of acrylic acid adduct (A2-2) was obtained. The non-volatile content of the water dispersion (A2-2) was 40% by weight.

The average particle diameter of the water dispersion (A2-2) was measured and found to be 0.25 ㎛. In addition, the aqueous dispersion (A2-2) showed no coagulation or flotation separation even when left at 50°C for 1 month, and had excellent static stability.

(Production Example (A2-3))

2-Acryloyloxyethyl-2-hydroxyethyl-phthalic acid/ethylene oxide 150 mol addition hardened castor oil ether/oxyethylene-oxypropylene block aggregate (weight average molecular weight 15,000, oxypropylene/oxyethylene=20/80 (weight ratio) )) = 70/20/10 (weight ratio) is placed in an emulsifying device, water is gradually added under stirring to emulsify the phase, and uniform 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid is formed. An aqueous dispersion (A2-3) was obtained. The non-volatile content of the water dispersion (A2-3) was 40% by weight.

The average particle diameter of the water dispersion (A2-3) was measured and found to be 0.29 μm. In addition, the aqueous dispersion (A2-3) showed no aggregation or flotation separation even when left at 50°C for 1 month, and had excellent static stability.

(Production Example (A2-4))

Trimethylolpropane trimethacrylate/oxyethylene-oxypropylene block aggregate (weight average molecular weight 15,000, oxypropylene/oxyethylene=20/80 (weight ratio))/oxyethylene-oxypropylene block aggregate (weight average molecular weight 2,000, oxypropylene A composition consisting of /oxyethylene = 60/40 (weight ratio) = 70/15/15 (weight ratio) is put into an emulsifier, and water is gradually added while stirring to emulsify the phase to form uniform trimethylolpropane trimethacrylate. An aqueous dispersion (A2-4) was obtained. The non-volatile content of the water dispersion (A2-4) was 40% by weight.

The average particle diameter of the water dispersion (A2-4) was measured and found to be 0.21 μm. In addition, the aqueous dispersion (A2-4) showed no aggregation or flotation separation even when left at 50°C for 1 month, and had excellent static stability.

The components used in the examples or comparative examples are as follows.

(B1): POE(8) bisphenol A ether (BA-8 glycol: from Nippon Nyukazai)

(B2): POE(10) bisphenol A ether (BA-10 glycol: from Nippon Nyukazai)

(B3): POE (17.5) bisphenol A ether (BLAUNON (registered trademark) BEO-17.5: Aoki Oil Industrial product)

(B4) POE distyrenated phenyl ether (EMULGEN (registered trademark) A-500)

The components used in the examples or comparative examples are as follows.

(C1): 20 molar adduct of 2,4,7,9-tetramethyl-5-decyne-4,7-diol with ethylene oxide

(C2): 5 molar adduct of 2,4,7,9-tetramethyl-5-decyne-4,7-diol with ethylene oxide

(C3): 3,6-dimethyl-4-octyne-3,6-diol

(C4): 2,4,7,9-tetramethyl-5-decyne-4,7-diol

The components used in the examples or comparative examples are as follows.

(D1): Water dispersion of epoxy resin

(Production Example (D1))

jER1001 (manufactured by Mitsubishi Chemical Corporation, broken bisphenol A type epoxy resin, epoxy equivalent 450 to 500)/jER828 (manufactured by Mitsubishi Chemical Corporation, liquid bisphenol A type epoxy resin, epoxy equivalent weight: 184 to 194)/POE (150) hydrogenated castor oil. A composition consisting of ether = 40/40/20 (weight ratio) was put into an emulsifier, and water was gradually added while stirring to emulsify the phase, thereby obtaining an aqueous dispersion (D1) of an epoxy resin with a non-volatile content of 30% by weight.

(E1): Mixed wax emulsion of oxidized polyethylene wax, beeswax, carnauba wax, and paraffin wax (40%)

As is clear from Tables 1 to 4, the sizing agent of the examples contains compound (A) and compound (B) represented by the formula (1), and the compound (A) is a specific aromatic polyester resin (A1). ) and compound (A2) having a specific ethylenically unsaturated group, and a specific amount of compound (A), so that the problem of the present application could be solved.

In particular, Examples 15 to 18 containing an acetylene-based surfactant (C) were particularly excellent in uniform adhesion.

On the other hand, as shown in Table 5, when compound (B) is not contained (Comparative Examples 1, 2, 3, 7, and 8), compound (B), which is an aromatic surfactant but represented by the formula (1), is If not (Comparative Example 3), if it is an aliphatic polyester but not an aromatic polyester resin (A1) (Comparative Example 4), or if it is an aromatic polyester resin but the structural units are different (Comparative Examples 5 and 6), the problem is It wasn't resolved.

《Industrial Applicability》

Fiber-reinforced composite materials in which matrix resin is reinforced with reinforcing fibers are used for automotive applications, aviation/space applications, sports/leisure applications, and general industrial applications. Reinforcing fibers include various inorganic fibers such as carbon fiber, glass fiber, and ceramic fiber, and various organic fibers such as aramid fiber, polyamide fiber, and polyethylene fiber.

Claims (5)

A sizing agent for reinforced fibers containing compound (A) and compound (B) represented by the following formula (1),
The compound (A) contains at least one selected from aromatic polyester resin (A1) and compound (A2) having an ethylenically unsaturated group,
The aromatic polyester resin (A1) is a polyester resin containing the following structural units (I) and (II) as structural units,
The ethylenically unsaturated group is at least one selected from a vinyl ester group, an acrylate group, and a methacrylate group,
A sizing agent for reinforced fibers, wherein the weight ratio of the compound (A) to the non-volatile content of the sizing agent for reinforced fibers is 10% by weight or more.
Constituent unit (I): selected from isophthalic acid, ester-forming derivatives of isophthalic acid, terephthalic acid, ester-forming derivatives of terephthalic acid, sulfoisophthalic acid, ester-forming derivatives of sulfoisophthalic acid and alkali metal salts of sulfoisophthalic acid. A structural unit formed by at least one type of
Constituent unit (II): Constituent unit formed of polyalkylene glycol
[Formula 1]

(In formula (1), R ¹ and R ² are each independently a hydrogen atom or an alkyl group. AO is an oxyalkylene group having 2 to 4 carbon atoms. m and n are each independently a number of 1 or more. ) According to paragraph 1,
A sizing agent for reinforced fibers, wherein the weight ratio (A/B) of the compound (A) and the compound (B) is 0.1 to 9.0. According to claim 1 or 2,
A sizing agent for reinforced fibers wherein the sum of m and n (m+n) is 8 to 60. A reinforcing fiber strand to which the sizing agent for reinforcing fiber according to any one of claims 1 to 3 is attached to the raw material reinforcing fiber strand. A fiber-reinforced composite material comprising a matrix resin and the reinforcing fiber strand according to claim 4.