CN117795153A - Sizing agent for reinforcing fibers and use thereof - Google Patents

Abstract

The invention provides a sizing agent with excellent high-temperature stability under high-concentration conditions, a reinforced fiber strand and a fiber reinforced composite material using the sizing agent. The present invention provides a sizing agent for reinforcing fibers, which contains a compound (A) and a compound (B) represented by the following general formula (1), wherein the compound (A) contains at least 1 selected from an aromatic polyester resin (A1) and a compound (A2) having an ethylenically unsaturated group, the aromatic polyester resin (A1) is a polyester resin containing the following structural unit (I) and structural unit (II) as structural units, the ethylenically unsaturated group is at least 1 selected from a vinyl ester group, an acrylate group and a methacrylate group, and the weight ratio of the compound (A) in a nonvolatile component of the sizing agent for reinforcing fibers is more than 10 wt%.

Description

Sizing agent for reinforcing fibers and use thereof

Technical Field

The present invention relates to a sizing agent for reinforcing fibers and use thereof. More specifically, the present invention relates to a sizing agent for reinforcing fibers used for reinforcing a matrix resin, a reinforcing fiber strand using the sizing agent for reinforcing fibers, and a fiber-reinforced composite material.

Background

Fiber-reinforced composite materials in which plastic materials (called matrix resins) are reinforced with various synthetic fibers are widely used in automotive applications, aerospace applications, sports and leisure applications, general industrial applications, and the like. The fibers used in these composite materials include various inorganic fibers such as carbon fibers, glass fibers, and ceramic fibers, and various organic fibers such as aramid fibers, polyamide fibers, and polyethylene fibers. These various synthetic fibers are usually produced in the form of filaments, and then processed into a sheet-like intermediate material called unidirectional prepreg by a hot melt method, a roll winding method, or the like, processed by a filament winding method, or processed into a fabric, a chopped fiber shape, or the like as the case may be, and then subjected to various high-precision processing steps to be used as reinforcing fibers.

Epoxy resins are widely used as matrix resins for reinforced fiber composites. In addition to epoxy resins, unsaturated polyester resins, vinyl ester resins, acrylic resins, and the like are also used as radical-polymerizable matrix resins.

In order to improve the mechanical strength of the reinforcing fiber composite material, it is important to improve the wettability and adhesion between the matrix resin and the reinforcing fibers, and sizing agents for improving the wettability and adhesion of the reinforcing fibers have been proposed for the epoxy resins and the radical polymerization matrix resins (for example, patent documents 1 and 2).

However, in the sizing agents described in patent document 1 and patent document 2, the performance of the sizing agent such as wettability and adhesion is reduced with time.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 53-52796

Patent document 2: japanese patent laid-open No. H06-173170

Disclosure of Invention

Problems to be solved by the invention

The reason why the performance of the sizing agent was lowered with time was examined, and as a result, it was found that the performance of the sizing agent was lowered with time at high temperature. It has been found that when the sizing agent is exposed to high temperatures for a long period of time, for example, by transportation to a high temperature region or storage in a place where the sizing agent has to be at a high temperature, the sizing agent becomes unstable and deteriorates and separates.

Accordingly, an object of the present invention is to provide a sizing agent excellent in high-temperature stability even under high-concentration conditions, and a reinforcing fiber strand and a fiber-reinforced composite material using the sizing agent.

Means for solving the problems

The present inventors have made intensive studies to solve the above problems, and as a result, have found that the above problems can be solved by providing a sizing agent for reinforcing fibers comprising a specific resin and a specific compound.

Specifically, 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), wherein the compound (a) contains at least 1 selected from the group consisting of an aromatic polyester resin (A1) and a 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 1 selected from the group consisting of a vinyl ester group, an acrylate group and a methacrylate group, and the weight ratio of the compound (a) to the nonvolatile component of the sizing agent for reinforcing fibers is 10% by weight or more.

Structural unit (I): a structural unit formed from at least 1 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;

structural unit (II): structural units formed from polyalkylene glycols.

[ chemical 1]

(in the formula (1), R ¹ R is R ² Each independently is 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. )

The ratio (A/B) of the weight ratio of the compound (A) to the compound (B) is preferably 0.1 to 9.0.

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

The reinforcing fiber strand of the present invention is produced by adhering the reinforcing fiber sizing agent to a raw material reinforcing fiber strand.

The fiber-reinforced composite material of the present invention comprises a matrix resin and the reinforcing fiber strands described above.

Effects of the invention

The sizing agent for reinforcing fibers of the present invention is excellent in high-temperature stability even at high concentrations. The sizing agent for reinforcing fibers of the present invention can impart excellent bundling properties to reinforcing fibers and can also impart excellent adhesion properties to matrix resins.

The reinforcing fiber strand of the present invention is free from aged deterioration of the sizing agent or less aged deterioration of the sizing agent, and therefore can suppress deterioration of the scratch fuzziness and the 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 having excellent physical properties can be obtained.

Detailed Description

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

[ Compound (A) ]

The compound (a) contains at least 1 selected from the group consisting of an aromatic polyester resin (A1) described later and a compound (A2) having an ethylenically unsaturated group described later. The compound (a) is a component that contributes to high-temperature stability at a high concentration of the sizing agent for reinforcing fibers of the present invention by being used in combination with the compound (B) described later. In addition, the polymer also functions as a component for improving bundling and adhesion.

When the compound (a) contains the aromatic polyester resin (A1), it is preferable in view of the effect of the present application.

The reason why the sizing agent for reinforcing fibers of the present invention is excellent in high-temperature stability even at high concentrations is not certain, however, it is considered that the use of the compound (a) and the compound (B) together is compatible with each other and improves the emulsifying property, and therefore the sizing agent is excellent in high-temperature stability even at high concentrations. It is considered that, when the compound (B) is not contained, insufficient emulsifying property is liable to occur, and therefore high-temperature stability at a high concentration is poor.

[ aromatic polyester resin (A1) ]

The aromatic polyester resin (A1) is a component contributing to the high-temperature stability at a high concentration of the sizing agent for reinforcing fibers of the present invention by being used in combination with a compound (B) described later. In addition, the polymer also functions as a component for improving bundling and adhesion.

The aromatic polyester resin (A1) is a copolymer of a polycarboxylic acid or an anhydride thereof and a polyol, is a polymer containing at least 1 aromatic compound of the polycarboxylic acid or an anhydride thereof and the polyol, and is a polymer having no vinyl ester group, acrylate group and methacrylate group in the molecule. The method for producing the aromatic polyester resin (A1) is not particularly limited, and a known method can be used. The aromatic polyester resin (A1) may be used in an amount of 1 or 2 or more.

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

Structural unit (I): a structural unit formed of one or more 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;

structural unit (II): structural units formed from polyalkylene glycols.

< structural Unit (I) >

The ester-forming derivative of isophthalic acid is a derivative of isophthalic acid, and is a derivative capable of forming an isophthalate ester by an esterification reaction or an ester exchange reaction. Specific examples of the ester-forming derivative of isophthalic acid include esters, anhydrides, and amides of isophthalic acid.

The ester-forming derivative of terephthalic acid is a derivative of terephthalic acid, and is a derivative capable of forming a terephthalic acid ester by an esterification reaction or an ester exchange reaction. Specific examples of the ester-forming derivative of terephthalic acid include esters, anhydrides, and amides of terephthalic acid.

The ester-forming derivative of sulfoisophthalic acid is a derivative of sulfoisophthalic acid, and is a derivative capable of forming a sulfoisophthalic acid ester by an esterification reaction or a transesterification reaction. Specific examples of the ester-forming derivative of sulfoisophthalic acid include esters, anhydrides, and amides of sulfoisophthalic acid.

Examples of the alkali metal salt of sulfoisophthalic acid include sodium 5-sulfoisophthalic acid, potassium 5-sulfoisophthalic acid, lithium 5-sulfoisophthalic acid, sodium 1, 3-dimethyl-5-sulfoisophthalic acid, potassium 1, 3-dimethyl-5-sulfoisophthalic acid and lithium 1, 3-dimethyl-5-sulfoisophthalic acid.

The structural unit (I) preferably contains isophthalic acid and sodium sulfoisophthalic acid salts, more preferably is formed only from isophthalic acid and sodium sulfoisophthalic acid salts.

< structural Unit (II) >

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

Examples of the polyalkylene glycol include diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, dibutylene glycol, and tributylene glycol. The structural unit (II) preferably contains diethylene glycol, more preferably is formed only from diethylene glycol.

The aromatic polyester resin (A1) is not limited as long as it contains the structural units (I) and (II) as the structural units, and may contain a structural unit formed of an aliphatic dicarboxylic acid as a structural unit other than the structural units (I) and (II).

In the production of the aromatic polyester resin (A1), at least 1 of the polycarboxylic acid or its anhydride (sometimes referred to as the whole polycarboxylic acid component) and the polyhydric alcohol may contain an aromatic compound, and it is preferable that 40 to 100 mol% of the whole polycarboxylic acid component is an aromatic dicarboxylic acid, and more preferable that 80 to 99 mol%.

In addition, from the viewpoint of emulsion stability when the aromatic polyester resin (A1) is prepared into an aqueous liquid, it is preferable that 1 to 10 mol% of the total polycarboxylic acid component is an aromatic dicarboxylic acid containing a sulfonate. Among the above-exemplified polycarboxylic acids and polyols, phthalic acid (japanese: febrile acid), terephthalic acid, isophthalic acid, phthalic acid (japanese: behent's acid), 1, 5-naphthalene dicarboxylic acid, 2, 6-naphthalene dicarboxylic acid, diphthalic acid, diphenoxyethane dicarboxylic acid, phthalic anhydride, sulfoterephthalate, 5-sulfoisophthalate are preferred, and aliphatic diols are preferred, and ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, 1, 4-butanediol, neopentyl glycol are particularly preferred as the polyol.

The weight average molecular weight of the aromatic polyester resin (A1) is preferably 3000 to 100000, more preferably 5000 to 30000 from the viewpoint of exhibiting the effects of the present application.

[ Compound having an ethylenically unsaturated group (A2) ]

The compound (A2) having an ethylenically unsaturated group (hereinafter, sometimes referred to as compound (A2)) is a component that contributes to the high-temperature stability at a high concentration of the sizing agent for a reinforcing fiber of the present invention by being used in combination with the compound (B) described later. In addition, the polymer also functions as a component for improving bundling and adhesion.

The compound (A2) is a compound having at least 1 selected from a vinyl ester group, an acrylate group and a methacrylate group. The compound (A2) may be used in an amount of 1 or 2 or more. 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-".

Examples of the compound (A2) include alkyl (meth) acrylates, alkoxypolyalkylene glycol (meth) acrylates, benzyl (meth) acrylates, phenoxyethyl (meth) acrylates, 2-hydroxyalkyl (meth) acrylates, dialkylaminoethyl (meth) acrylates, glycidyl (meth) acrylates, 2-methacryloyloxyethyl 2-hydroxypropyl phthalate, polyalkylene glycol di (meth) acrylates, alkylene glycol di (meth) acrylates, glycerol di (meth) acrylates, 2-hydroxy-3-acryloxypropyl (meth) acrylates, dimethylol-tricyclodecane di (meth) acrylates, bisphenol A (meth) acrylates, alkylene oxide addition bisphenol A (meth) acrylates, bisphenol A diglycidyl ether (meth) acrylic acid adducts, alkylene oxide addition bisphenol A diglycidyl ether (meth) acrylic acid adducts, trimethylolpropane tri (meth) acrylates, glycidyl (meth) acrylates, phenoxyalkyl (meth) acrylates, phenoxypolyalkylene glycol (meth) acrylates, 2-hydroxy-3-phenoxysuccinic (meth) acrylates, polyoxyethylene (meth) acrylates, and polyoxyethylene (2- (meth) acrylates, 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl-2-hydroxyethyl-phthalate, neopentyl glycol (meth) acrylate benzoate, alkylene oxide addition trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol tri (meth) acrylate hexamethylene diisocyanate urethane prepolymer, and the like.

Among them, the compound (A2) preferably has at least 1 selected from the group consisting of an oxyalkylene group and an aryl group, and more preferably contains an aryl group, from the viewpoint of excellent adhesion to a matrix resin. Specifically, 2-methacryloyloxyethyl 2-hydroxypropyl phthalate, polyalkylene glycol di (meth) acrylate, 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl-2-hydroxyethyl-phthalate, neopentyl glycol (meth) acrylate, bisphenol a (meth) acrylate, alkylene oxide addition bisphenol a (meth) acrylate, bisphenol a diglycidyl ether (meth) acrylic acid adduct, alkylene oxide addition bisphenol a diglycidyl ether (meth) acrylic acid adduct, more preferably polyalkylene glycol di (meth) acrylate, bisphenol a (meth) acrylate, alkylene oxide addition bisphenol a (meth) acrylate, bisphenol a diglycidyl ether (meth) acrylate, bisphenol a diglycidyl ether (meth) acrylate, and particularly preferably bisphenol a (meth) acrylate, alkylene oxide addition bisphenol a (meth) acrylate, bisphenol a diglycidyl ether (meth) acrylic acid adduct, alkylene oxide addition bisphenol a diglycidyl ether (meth) acrylic acid adduct.

[ Compound (B) ]

The compound (B) used in the sizing agent for reinforcing fibers of the present invention is a compound 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 skeleton.

By combining the compound (B) with the compound (a) in this manner, the high-temperature stability at a high concentration can be improved.

In the general formula (1), R ¹ R is R ² Each independently is a hydrogen atom or an alkyl group. The carbon number of the alkyl group is preferably 1 to 2, 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, 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 even more preferably 4 to 10. In order to further exhibit 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, still more preferably 8 to 30, particularly preferably 8 to 20, and most preferably 10 to 20.

From the viewpoint of exerting the effects of the present application, the molecular weight distribution (Mw/Mn) of the 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.

The molecular weight distribution of the compound (B) can be determined by GPC using the compound (B) as a test sample. The compound (B) is not a monodisperse compound, but a compound having a broad distribution state of a given molecular weight distribution is used, whereby high-temperature stability is excellent also at a high concentration. In the present specification, the term "high concentration" preferably means a concentration of 30 wt% or more, and the effects of the present application are exhibited in the order of more than 30 wt%, 35 wt% or more, 40 wt% or more, 50 wt% or more, and 60 wt% or more (the higher the concentration is, the more the effects of the present application are exhibited).

The addition amounts of alkylene oxide added to both ends of the center portion of the bisphenol-based skeleton in the compound (B) do not need to be uniform to the left and right of the center portion, but since the compound (B) is usually a compound obtained by adding alkylene oxide to bisphenol compounds, the addition amounts of alkylene oxide added to both ends of the center portion of the bisphenol-based skeleton often differ little.

[ alkyne-based surfactant (C) ]

From the viewpoint of exerting the effects of the present application, the sizing agent for reinforcing fibers of the present invention preferably contains an alkyne-based surfactant (C). The use of the compound (a) and the alkyne-based surfactant (C) in combination can also reduce the surface tension and improve the uniform adhesion to the reinforcing fiber bundles.

The alkyne-based surfactant is a compound having hydrophilic groups such as an alkynyl group and a hydroxyl group in its molecular structure. The alkyne-based surfactant (C) may be used singly or in combination.

The alkyne-based surfactant (C) is preferably at least 1 selected from the group consisting of an alkynol (C1), an alkyndiol (C2), a compound (C3) obtained by adding an alkylene oxide to an alkynol, and a compound (C4) obtained by adding an alkylene oxide to an alkyndiol. Among them, the compound (C3) obtained by adding an alkylene oxide to an alkynol and the compound (C4) obtained by adding an alkylene oxide to an alkynediol are preferable, and the compound (C4) obtained by adding an alkylene oxide to an alkynediol is more preferable.

The alkynol (C1) is a compound having an alkynyl group and 1 hydroxyl group in the molecular structure.

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

The alkynediol (C2) is a compound having an alkynyl group and 2 hydroxyl groups in the molecular structure.

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

The compound (C3) obtained by adding an alkylene oxide to an alkynol is a compound obtained by adding an alkylene oxide to a hydroxyl group of an alkynol.

The compound (C3) obtained by adding an alkylene oxide to an alkynol is preferably a compound represented by the following general formula (4).

The compound (C4) obtained by adding an alkylene oxide to an acetylenic diol is a compound obtained by adding an alkylene oxide to at least 1 hydroxyl group of an acetylenic diol.

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

[ chemical 2]

(in the formula (2), R ³ R is R ⁴ Each independently represents an alkyl group having 1 to 8 carbon atoms. )

[ chemical 3]

(in the formula (3), R ⁵ 、R ⁶ 、R ⁷ R is R ⁸ Each independently represents an alkyl group having 1 to 8 carbon atoms. )

[ chemical 4]

(in the formula (4), R ³ R is R ⁴ Each independently represents an alkyl group having 1 to 8 carbon atoms. R is R ⁹ Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. AO represents an oxyalkylene group having 2 to 4 carbon atoms. p is a number of 1 to 50. )

[ chemical 5]

(in the formula (5), R ⁵ 、R ⁶ 、R ⁷ R is R ⁸ Each independently represents an alkyl group having 1 to 8 carbon atoms. R is R ⁹ Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. In the formula (5), R is plural 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 of 1 to 50. )

In the formula (2) and the formula (4), R ³ R is R ⁴ Each independently represents an alkyl group having 1 to 8 carbon atoms. The alkyl group may be linear or branched. 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 the formulas (3) and (5), R ⁵ 、R ⁶ 、R ⁷ R is R ⁸ Each independently represents an alkyl group having 1 to 8 carbon atoms. The alkyl group may be linear or branched. 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 the formula (4) and the formula (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 the formula (4) and the formula (5), AO independently represents an oxyalkylene group having 2 to 4 carbon atoms. Namely, represents an oxyethylene group, oxypropylene group or oxybutylene group. As the oxyalkylene group, an oxyethylene group and an oxypropylene group are preferable, and an oxyethylene group is more preferable. Composition (AO) _p Or (AO) _q The AO of (2) may be 1 or 2 or more. In the case of 2 or more kinds, the polymer may be any of block adducts, alternating adducts, and random adducts.

In the formula (4), p is a number of 1 to 50. p is preferably 1 to 45, more preferably 1 to 40, and still more preferably 1 to 35.

In the formula (5), p and q are each independently a number of 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.

From the viewpoint of exerting the effects of the present application, the HLB of the alkyne-based surfactant (C) is preferably 4 to 25, more preferably 5 to 20, and even more preferably 6 to 18. HLB of the present invention can be experimentally determined by the Atlas method proposed by Griffin et al.

The alkyne-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 a raptor reaction in which a ketone or aldehyde is reacted with an alkyne under pressure in the presence of a catalyst such as an alkali or metal compound.

The compound (C3) or the compound (C4) can be obtained by addition polymerization of an alkylene oxide (e.g., ethylene oxide and/or propylene oxide) in the presence of a catalyst such as an alkali or a metal compound, in the presence of an alkynol (C1) or an alkyndiol (C2).

(resin (D) other than Compound (A))

The resin (D) other than the compound (a) may be at least 1 selected from polyurethane resins, epoxy resins, polyamide resins, polyolefin resins, and phenolic resins.

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.

Examples of the aromatic polyisocyanate compound include toluene-2, 4-diisocyanate, toluene-2, 6-diisocyanate, xylene diisocyanate, naphthalene-1, 5-diisocyanate, mono-or dichlorophenyl-2, 4-diisocyanate, diphenylmethane-4, 4 '-diisocyanate, 3' -dimethyldiphenylmethane-4, 4 '-diisocyanate, 3-methyldiphenylmethane-4, 4' -diisocyanate, m-phenylene-diisocyanate, p-phenylene-diisocyanate, and triphenylmethane triisocyanate.

Examples of the aliphatic polyisocyanate compound include 1, 6-hexamethylene diisocyanate, propyl diisocyanate, and butyl diisocyanate. As the polyisocyanate compound, 1 or 2 or more of the above-exemplified polyisocyanate compounds may be used in combination.

Examples of the polyhydric alcohol include polyether polyols such as polyethylene glycol, polypropylene glycol, and ethylene oxide and/or propylene oxide adducts of bisphenol a, polyester polyols as condensates of polyhydric alcohols with polybasic acids such as succinic acid, adipic acid, and phthalic acid, polyhydric alcohols having carboxyl groups and 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.

The epoxy resin is a compound having 2 or more reactive epoxy groups in the molecular structure. The epoxy resin is typically a glycidyl ether type obtained from epichlorohydrin and an active hydrogen compound, and examples thereof include a glycidyl ester type, a glycidylamine type, and an alicyclic type. The epoxy resin may be 1 kind, or 2 or more kinds may be used in combination.

The epoxy resin is not particularly limited as long as it has a hydroxyl group, and examples thereof include various modified epoxy resins such as bisphenol a type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, alkylphenol novolac type epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, and amine modified aromatic epoxy resin.

The polyamide resin is not particularly limited as long as it is a resin in which a main chain is formed by repeating an amide bond, and examples thereof include polyamide 6 (obtained by ring-opening polymerization of epsilon-caprolactam), polyamide 66 (obtained by polycondensation of hexamethylenediamine and adipic acid), and a polyamide resin in which a hydrophilic group is introduced into a main chain to be water-soluble.

Examples of the polyolefin include homopolymers and copolymers of olefins such as polyethylene, polypropylene, ethylene-propylene copolymers and poly (methylpentene-1), and copolymers of olefins and copolymerizable monomers (ethylene-vinyl acetate copolymers, ethylene- (meth) acrylic acid ester copolymers, and the like). These polyolefin resins may be used singly or in combination of two or more. The polyolefin resin includes polypropylene resins having a propylene content of 50 wt% or more (particularly 75 to 100 wt%), for example, polypropylene, propylene-ethylene copolymers, propylene-butene copolymers, propylene-ethylene-butene copolymers, and the like.

Examples of the phenolic resin include resins obtained by condensing phenols such as phenol, cresol, xylenol, t-butylphenol, nonylphenol, cashew oil, lignin, resorcinol, catechol and the like with aldehydes such as formaldehyde, acetaldehyde, furfural and the like, and examples thereof include linear phenolic resins and resol resins. The novolac resin can be obtained by reacting phenol with formaldehyde in the presence of an acid catalyst such as oxalic acid or the like in the same amount or in an excess of phenol. Resol resins can be obtained by reacting phenol with formaldehyde in the presence of a base catalyst such as sodium hydroxide, ammonia, or an organic amine in the presence of the same amount or in excess of formaldehyde.

The sizing agent for reinforcing fibers of the present invention may contain a surfactant other than the above-mentioned alkyne-based surfactant (C) (hereinafter, simply referred to as other surfactant).

In the case where the sizing agent contains a water-insoluble or poorly water-soluble resin, the water-based emulsification can be efficiently performed by using the sizing agent as an emulsifier.

The other surfactant is not particularly limited, and a known surfactant may be appropriately selected from nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants other than the above-mentioned alkyne-based surfactant (C). The surfactant may be used in an amount of 1 or 2 or more.

Examples of the nonionic surfactant include nonionic surfactants such as alkylene oxide-added surfactants (surfactants obtained by adding alkylene oxides (2 or more kinds may be used in combination) such as ethylene oxide and propylene oxide to higher alcohols, higher fatty acids, alkylphenols, styrenated phenols, benzyl phenols, glycerin, pentaerythritol, sorbitol, sorbitan esters, castor oil, hydrogenated castor oil, higher aliphatic amines, fatty acid amides, oils and fats), surfactants obtained by adding higher fatty acids to polyalkylene glycols, ethylene oxide/propylene oxide copolymers, esters of polyhydric alcohols and fatty acids, and aliphatic alkanolamides.

More specifically, examples of the nonionic surfactant include polyoxyalkylene linear alkyl ethers such as polyoxyethylene hexyl ether, polyoxyethylene octyl ether, polyoxyethylene decyl ether, polyoxyethylene lauryl ether, and polyoxyethylene cetyl ether; polyoxyalkylene branched primary alkyl ethers such as polyoxyethylene 2-ethylhexyl ether, polyoxyethylene isocetyl ether and polyoxyethylene isostearyl ether; polyoxyalkylene branched secondary alkyl ethers such as polyoxyethylene 1-hexyl ether, polyoxyethylene 1-octyl hexyl ether, polyoxyethylene 1-hexyl octyl ether, polyoxyethylene 1-pentyl heptyl ether, and polyoxyethylene 1-heptyl pentyl ether; polyoxyalkylene alkenyl ethers such as polyoxyethylene oleyl ether; polyoxyalkylene alkylphenyl ethers such as polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether and polyoxyethylene dodecylphenyl ether; polyoxyalkylene alkylaryl phenyl ethers such as polyoxyethylene tristyrylphenyl ether, polyoxyethylene distyrylphenyl ether, polyoxyethylene styrylphenyl ether, polyoxyethylene tristyrylmethyl phenyl ether, polyoxyethylene distyrylmethyl phenyl ether, polyoxyethylene tribenzylphenyl ether, polyoxyethylene dibenzylphenyl ether, and polyoxyethylene benzyl phenyl ether; polyoxyalkylene fatty acid esters such as polyoxyethylene monolaurate, polyoxyethylene monooleate, polyoxyethylene monostearate, polyoxyethylene monomyristate, polyoxyethylene dilaurate, polyoxyethylene dioleate, polyoxyethylene dimyristate and polyoxyethylene distearate; sorbitan esters such as sorbitan monopalmitate and sorbitan monooleate; polyoxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monostearate and polyoxyethylene sorbitan monooleate; glycerol fatty acid esters such as glycerol monostearate, glycerol monolaurate and glycerol monopalmitate; polyoxyalkylene sorbitol fatty acid esters; sucrose fatty acid ester; polyoxyalkylene castor oil ethers such as polyoxyethylene castor oil ether; polyoxyalkylene hydrogenated castor oil ether such as polyoxyethylene hydrogenated castor oil ether; polyoxyalkylene alkyl amino ethers such as polyoxyethylene lauryl Gui Jian ether and polyoxyethylene stearyl amino ether; ethylene oxide-propylene oxide block or random copolymers; terminal alkyl etherate of ethylene oxide-propylene oxide block or random copolymer; a terminal sucrose etherate of an ethylene oxide-propylene oxide block or random copolymer; etc.

Examples of the anionic surfactant include carboxylic acid (salt), sulfuric acid ester salt of higher alcohol/higher alcohol ether, sulfonic acid salt, phosphoric acid ester salt of higher alcohol/higher alcohol ether, and the like.

More specifically, examples of the anionic surfactant include fatty acids (salts) such as oleic acid, palmitic acid, oleic acid sodium salt, palmitic acid potassium salt, and oleic acid triethanolamine salt; hydroxy group-containing carboxylic acids (salts) such as glycolic acid, potassium glycolate, lactic acid, and potassium lactate; polyoxyalkylene alkyl ether acetic acid (salts) such as polyoxyethylene tridecyl ether acetic acid (sodium salt); salts of carboxyl-polysubstituted aromatic compounds such as potassium trimellitate and potassium pyromellitate; alkylbenzenesulfonic acids (salts) such as dodecylbenzenesulfonic acid (sodium salt); polyoxyalkylene alkyl ether sulfonic acid (salts) such as polyoxyethylene 2-ethylhexyl ether sulfonic acid (potassium salt); higher fatty acid amide sulfonic acids (salts) such as stearoyl methyl taurate (sodium), lauroyl methyl taurate (sodium), myristoyl methyl taurate (sodium), palmitoyl methyl taurate (sodium); n-acyl sarcosinates such as lauroyl sarcosinate (sodium); alkyl phosphonic acids (salts) such as octyl phosphonate (potassium salt); aromatic phosphonic acids (salts) such as phenylphosphonates (potassium salts); alkyl phosphonic acids (salts) such as 2-ethylhexyl phosphonate (potassium salt); nitrogen-containing alkyl phosphonic acids (salts) such as aminoethyl phosphonic acid (diethanolamine salts); alkyl sulfates (salts) such as 2-ethylhexyl sulfate (sodium salt); polyoxyalkylene sulfate esters (salts) such as polyoxyethylene 2-ethylhexyl ether sulfate (sodium salt); long-chain N-acyl glutamate such as sodium di-2-ethylhexyl sulfosuccinate, sodium dioctyl sulfosuccinate, etc., long-chain sulfosuccinate such as sodium N-lauroyl glutamate, disodium N-stearoyl-L-glutamate, etc.; etc.

Examples of the cationic surfactant include alkyl quaternary ammonium salts such as 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, coco-alkyl trimethyl ammonium chloride, tallow alkyl trimethyl ammonium chloride, stearyl trimethyl ammonium bromide, coco-alkyl trimethyl ammonium bromide, cetyl trimethyl ammonium methyl sulfate, oleyl dimethyl ethyl ammonium ethyl sulfate, dioctyl dimethyl ammonium chloride, dilauryl dimethyl ammonium chloride, distearyl dimethyl ammonium chloride, and stearyl diethyl methyl ammonium sulfate; (polyoxyalkylene) alkyl amino ether salts such as (polyoxyethylene) lauryl amino 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 amine ethyl sulfate, di (polyoxyethylene) lauryl methyl ammonium dimethyl phosphate, di (polyoxyethylene) stearyl amine lactate, and the like; acyl amide alkyl quaternary ammonium salts such as N- (2-hydroxyethyl) -N, N-dimethyl-N-stearamide propyl ammonium nitrate, lanolin fatty acid amide propyl ethyl dimethyl ammonium ethyl sulfate, lauramide ethyl methyl diethyl ammonium methyl sulfate; alkyl ethyleneoxy quaternary ammonium salts such as dipalmityl polyethylene ethyleneoxy ethyl ammonium chloride and distearyl polyethylene oxy methyl ammonium chloride; alkyl isoquinolinium salts such as lauryl isoquinolinium chloride; benzalkonium salts such as lauryldimethylbenzyl ammonium chloride and stearyldimethylbenzyl ammonium chloride; benzethonium salts such as benzyl dimethyl {2- [2- (p-1, 3-tetramethylbutylphenoxy) ethoxy ] ethyl } ammonium chloride; pyridinium salts such as cetyl pyridinium chloride; imidazolinium salts such as oleyl hydroxyethyl imidazolinium ethyl sulfate and lauryl hydroxyethyl imidazolinium ethyl sulfate; acyl basic amino acid alkyl ester salts such as N-cocoyl arginine ethyl ester pyrrolidone carboxylate and N-lauroyl lysine ethyl ester chloride; primary amine salts such as laurylamine chloride, stearylamine bromide, hydrogenated tallow alkyl amine chloride, and rosin amine acetate; secondary salts such as cetyl methyl amine sulfate, lauryl methyl amine chloride, dilauryl amine acetate, stearyl ethyl amine bromide, lauryl propyl amine acetate, dioctyl amine chloride, and stearyl ethyl amine hydroxide; tertiary amine salts such as dilaurylmethylamine sulfate, lauryl diethyl amine chloride, lauryl ethyl methyl amine bromide, diethanol stearyl amide ethyl amine trihydroxyethyl phosphate, stearyl amide ethyl ethanolamine urea polycondensate acetate; fatty acid amide guanidinium salts; alkyl trialkylene glycol ammonium salts such as lauryl triethylene glycol ammonium hydroxide.

Examples of the amphoteric surfactant include imidazoline-based amphoteric surfactants such as 2-undecyl-N, N- (hydroxyethylcarboxymethyl) -2-imidazoline sodium salt, 2-cocoyl-2-imidazolinium hydroxide-1-carboxyethoxy 2 sodium salt; betaine amphoteric surfactants such as 2-heptadecyl-N-carboxymethyl-N-hydroxyethyl imidazolium 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-laurylglycine, N-laurylβ -alanine, N-stearyl β -alanine, sodium laurylaminopropionate, and the like.

The sizing agent for reinforcing fibers of the present invention may contain a smoothing agent (E). Examples of the smoothing agent include esters of higher fatty acids and higher alcohols, natural oils and fats (coconut oil, tallow, olive oil, rapeseed oil, etc.), liquid paraffin, wax, and the like. Examples of higher fatty acids are 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, oxidized polyethylene, oxidized polypropylene, modified polyethylene, modified polypropylene, paraffin wax, candelilla wax, carnauba wax, rice bran wax, and beeswax.

The amount of the smoothing agent is preferably 0.1 to 20% by weight, more preferably 1 to 10% by weight, based on the nonvolatile content of the sizing agent for reinforcing fibers.

The smoothing agent preferably contains fatty acids and/or alcohols having 30 or more carbon atoms and esters thereof from the viewpoint of scratch resistance and fuzziness. Examples thereof include candelilla wax and carnauba wax.

(sizing agent for reinforcing fibers ]

In the sizing agent for reinforcing fibers of the present invention, the weight proportion of the compound (a) in the nonvolatile component 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% by weight, still more preferably 80% by weight, particularly preferably 75% by weight, and most preferably 70% by weight. On the other hand, the lower limit of the weight ratio is more preferably 15% by weight, still more preferably 20% by weight, particularly preferably 22% by weight, and most preferably 24% by weight.

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

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

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

When the sizing agent for reinforcing fibers of the present invention contains the alkyne-based surfactant (C), the weight ratio ((C)/(a) + (B)) of the alkyne-based surfactant (C) to the total weight of the compound (a) and the compound (B) is preferably 0.001 to 0.15 from the viewpoint of long-term storage stability.

The method for producing the sizing agent of the present invention is not particularly limited, and a known method can be used. Examples of the method include: a method of adding each component constituting the sizing agent to water under stirring to prepare an aqueous solution, an emulsion or a water-dispersed product; a method for producing an aqueous solution, an emulsion or a water-dispersible product in the production of each component constituting the sizing agent; a method of adding each component constituting the sizing agent to water to which a surfactant is added with stirring, and emulsifying or dispersing the mixture; a method in which the components constituting the sizing agent are mixed in an emulsified dispersion in which emulsification and dispersion are performed in advance; a method in which the components constituting the sizing agent are mixed and the resulting mixture is heated to a softening point or higher, and then water is slowly added to the mixture while applying mechanical shearing force using a homogenizer, a homomixer, a ball mill, or the like, thereby performing phase inversion emulsification; and a method in which the emulsified dispersion liquid, which has been emulsified and dispersed, is mixed with water in an oil-feeding bath to which a sizing agent is added.

The sizing agent of the present invention is preferably self-emulsified and/or emulsified and dispersed in water. The average particle diameter of the sizing agent when self-emulsifying and/or emulsion-dispersing in water is not particularly limited, but is preferably 10 μm or less, more preferably 0.01 to 1 μm, and still more preferably 0.01 to 0.5 μm from the viewpoint of storage stability. If the average particle diameter is larger than 10 μm, the sizing agent itself may separate within several days, and the storage stability may be poor and may not be practical. The average particle diameter in the present invention refers to an average value calculated from a particle size distribution measured by a laser diffraction/scattering particle size distribution measuring apparatus (horiba LA-920).

The concentration of the nonvolatile component of the sizing agent of the present invention is not particularly limited. From the viewpoint of exhibiting the effect of the present application of excellent high-temperature stability at high concentrations, the lower limit of the weight ratio of the nonvolatile components in the entire sizing agent is preferable 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 ratio of the nonvolatile components in the entire sizing agent is preferably 100% by weight.

[ reinforcing fiber bundle ]

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

The method for producing a reinforcing fiber strand according to the present invention is a method for producing a reinforcing fiber strand comprising a sizing step of adhering the sizing agent for reinforcing fibers to a raw synthetic fiber strand and drying the obtained adhered substance.

The method for attaching the sizing agent for reinforcing fibers to the raw synthetic fiber strand to obtain an attached matter is not particularly limited as long as the sizing agent for reinforcing fibers is attached to the raw synthetic fiber strand by a kiss roll method, a roll dipping method, a spray method or other known methods. Among these methods, the roll impregnation method is preferable because the sizing agent for reinforcing fibers can be uniformly adhered to the raw material synthetic fiber strands.

The method for drying the obtained deposit is not particularly limited, and for example, the deposit may be dried by heating using a heating roller, hot air, a hot plate, or the like.

In the case of attaching the sizing agent for reinforcing fibers of the present invention to the raw material synthetic fiber strand, all the constituent components of the sizing agent for reinforcing fibers may be attached after mixing, or the constituent components may be attached separately in two or more stages. In addition, a thermosetting resin such as an epoxy resin or a phenol resin and/or a thermoplastic resin such as a polyolefin resin, a nylon resin, a polycarbonate resin, a polyester resin, a polyacetal resin, an ABS resin, a phenoxy resin, a polymethyl methacrylate resin, a polyphenylene sulfide resin, a polyetherimide resin, a polyether ketone resin other than the polymer component of the present invention may be attached to the raw material synthetic fiber bundle within a range that does not hinder the effect of the present invention.

The reinforcing fiber strand of the present invention is used as reinforcing fibers of a composite material comprising various thermosetting resins or various thermoplastic resins as matrix resins, and may be used in the form of continuous fibers or cut into a predetermined length.

The amount of the non-volatile component of the reinforcing fiber sizing agent to be attached to the raw synthetic fiber strand may be appropriately selected as long as the amount is set to be an amount necessary to provide the synthetic fiber strand with a desired function, and the amount of the non-volatile component to be attached is preferably 0.1 to 20% by weight relative to the raw synthetic fiber strand. In the synthetic fiber yarn bundle in the state of continuous fibers, the amount of the synthetic fiber yarn bundle attached is more preferably 0.1 to 10% by weight, still more preferably 0.5 to 5% by weight, relative to the raw synthetic fiber yarn bundle. The amount of the wire harness cut to a predetermined length is more preferably 0.5 to 20 wt%, and still more preferably 1 to 10 wt%.

If the amount of the sizing agent for reinforcing fibers is small, the bundling property of the synthetic fiber strands may be insufficient, and the workability may be deteriorated. In addition, if the amount of the sizing agent for reinforcing fibers is too large, the synthetic fiber strands become too rigid, and the resin impregnation property may be deteriorated during composite molding, which is not preferable.

Examples of the synthetic fibers of the synthetic fiber strands to which the sizing agent for reinforcing fibers of the present invention can be applied include various inorganic fibers such as carbon fibers, glass fibers and ceramic fibers, various organic fibers such as aramid fibers, polyethylene terephthalate fibers, polybutylene terephthalate fibers, polyethylene naphthalate fibers, polyarylate fibers, polyacetal fibers, PBO fibers, polyphenylene sulfide fibers and polyketone fibers. From the viewpoint of physical properties of the obtained fiber-reinforced composite material, at least 1 selected from the group consisting of carbon fibers, aramid fibers, polyethylene terephthalate fibers, polybutylene terephthalate fibers, polyethylene naphthalate fibers, polyarylate fibers, polyacetal fibers, PBO fibers, polyphenylene sulfide fibers, and polyketone fibers is preferable. More preferably carbon fibers.

[ fiber-reinforced composite material ]

The fiber-reinforced composite of the present invention comprises a thermosetting matrix resin or a thermoplastic matrix resin and the aforementioned strands of reinforcing fibers. Since the reinforcing fiber strands are treated with the sizing agent for reinforcing fibers of the present invention, the affinity between the reinforcing fiber strands and the thermoplastic matrix resin is good, and the fiber-reinforced composite material is excellent in adhesion.

The fiber-reinforced composite of the present invention comprises a matrix resin and the aforementioned bundles of reinforcing fibers. The fiber-reinforced composite material is obtained by treating a fiber-reinforced strand with the sizing agent of the present invention, wherein the sizing agent is uniformly adhered, and the affinity between the fiber-reinforced strand and the matrix resin is improved, thereby exhibiting excellent adhesion. In addition, thermal decomposition of the sizing agent during high-temperature treatment can be suppressed, and adhesion inhibition with the matrix resin due to thermal decomposition can be suppressed. The matrix resin herein means a matrix resin containing a thermosetting resin or a thermoplastic resin, and may contain 1 or 2 or more kinds. The thermosetting resin is not particularly limited, and examples thereof include epoxy resins, phenolic resins, unsaturated polyester resins, vinyl ester resins, cyanate ester resins, polyimide resins, and the like. The thermoplastic resin is not particularly limited, and examples thereof 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, and the like. Among them, thermosetting resins are preferable, and epoxy resins and vinyl ester resins are more preferable, because the effect of improving the adhesion by the sizing agent of the present invention is higher.

For the purpose of further improving the adhesion to the reinforcing fiber bundles, the matrix resin may be a resin in which a part or the whole of the matrix resin is modified.

The method for producing the fiber-reinforced composite material is not particularly limited, and known methods such as composite injection molding based on chopped fibers, long fiber particles, etc., compression molding based on UD sheets, fabric sheets, etc., and filament winding molding can be used.

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

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples described herein. The percentages (%) and parts shown in the following examples are not particularly limited, and are "wt%", and "parts by weight". The measurement of each characteristic value was performed by the method shown below.

The mixture was stirred to have a nonvolatile composition shown in the following table, and diluted with water to prepare a sizing agent having a nonvolatile concentration of 20 wt%. Then, the resulting sizing agent was diluted with water to prepare a sizing agent diluted solution having a nonvolatile content of 3% by weight. The numerical values in the table indicate the weight ratio of each component (in the case of the aqueous dispersion, the nonvolatile component thereof) to the nonvolatile component of the sizing agent.

Then, the prepared sizing agent diluent was impregnated with a sizing agent untreated carbon fiber bundle (fineness 800tex, filament number 12000) by Dip Nip method, and then dried with hot air at 105 ℃ for 15 minutes to obtain a sizing agent treated carbon fiber bundle. The carbon fiber strands were treated with the obtained sizing agent, and the bundling property, the adhesion property, the scratch resistance, the storage stability and the uniform adhesion were evaluated by the methods shown below.

< adhesion Rate of treatment agent >

About 10g of the fiber to which the sizing agent composition was applied was fed into a Soxhlet extractor, and extraction was performed with methyl ethyl ketone for 2 hours, and the weight difference between the fiber before and after extraction was calculated.

< bundling property >

Each sizing agent (diluted with water to 3% and target adhesion rate 1%) was applied to the carbon fiber, and 10 pieces of the obtained material were cut out with a cutter blade at a length of 5mm, and whether or not the loosening occurred was visually evaluated. The judgment was made based on the following evaluation criteria, and the excellent and o were regarded as acceptable.

And (3) the following materials: loosening less than 2;

o: 3-4 pieces of pine;

delta: 5-7 pieces of pine;

x: more than 8 pieces of the soybean milk are loosened.

< adhesion >

The adhesion was evaluated by the droplet method using a composite interface property evaluation device HM410 (manufactured by grong industries, ltd.).

From the carbon fiber bundles obtained in examples and comparative examples, carbon fiber filaments were taken out and set in a sample holder. Droplets of each matrix resin were formed on the carbon fiber filaments, and a sample for measurement was obtained. The measurement sample was set in the apparatus, the droplet was held by the apparatus blade, and the carbon fiber filament was allowed to travel on the apparatus at a speed of 0.06 mm/min, and the maximum pullout load F at the time of pulling out the droplet from the carbon fiber filament was measured.

The interfacial shear strength τ was calculated by the following formula, and the adhesiveness between the carbon fiber filaments and each matrix resin was evaluated. The following epoxy resins and vinyl ester resins were used as matrix resins. The curing method of the matrix resin is shown below.

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

( F: maximum pull-out load; d: carbon fiber filament diameter; l: particle diameter in the pull-out direction of the droplet. )

< method for solidifying droplets of matrix resin >

The matrix resin uses an epoxy resin and a vinyl ester resin.

Epoxy resin: a droplet of a matrix resin prepared by adjusting 100 parts by weight of epoxy resin jER828 (Mitsubishi chemical Co., ltd.) and 3 parts by weight of DICY (Mitsubishi chemical Co., ltd.) was heated at 80℃for 1 hour and 150℃for 3 hours, and cured.

Vinyl ester resin: a droplet of a matrix resin prepared by adjusting 100 parts by weight of RIPOXY R-806 (manufactured by Showa Denko Co., ltd.) and 2 parts by weight of PERCURE O (manufactured by Nikko Co., ltd.) was heated at 80℃for 1 hour and 150℃for 3 hours, and cured.

< scratch resistance >

The carbon fiber bundles obtained in examples and comparative examples were rubbed 1000 times (reciprocating speed 300 times/min) with 3 mirror-surface chrome-plated stainless steel needles arranged alternately at a tension of 50g using TM friction cohesion tester TM-200 (manufactured by glorious scientific finisher corporation), and the state of fuzzing of the carbon fiber bundles was visually determined based on the following criteria, and were regarded as good.

And (3) the following materials: the generation of fluff was not observed at all as before the rubbing.

O: although several fluff were observed, it was a level where there was no problem in practical use.

Delta: a large amount of fuzzing was observed, and some breakage was also confirmed.

X: it was confirmed that there were very much fuzzing and breakage of the monofilaments.

< high temperature stability >

Each sizing agent diluted with water so that the nonvolatile content was 20 wt% was stored in a constant temperature tank adjusted to 40 ℃, the appearance of the solution was visually confirmed, and the stability of the solution was judged based on the following evaluation criteria, and "excellent" and "o" were regarded as acceptable.

And (3) the following materials: there was no separation for 60 days.

O: there was no separation for 30 days, and separation was within 60 days.

Delta: no separation occurred for 7 days, and separation was performed within 30 days.

X: separation was performed within 7 days.

< uniform adhesion >

The following felt sedimentation test was used to evaluate the uniform adhesion.

A woven felt S20 (No. 103) made by Nikke corporation cut into 2cm by 2cm was floated on 100mL of each sizing agent dilution diluted with water to 1% of the active ingredient, and the time (seconds) until sedimentation was measured, and the uniform adhesion was evaluated. Temperature: 23 ℃. The shorter the time until sedimentation, the more excellent the uniform adhesion.

The index is defined as "good".

Very good (verygood): 90 seconds or less;

good (goodo): greater than 90 seconds and less than 180 seconds;

slight failure (Δ): more than 180 seconds and 300 seconds or less;

poor (×): greater than 300 seconds.

The compounds used in the examples are shown below.

(A1-1): copolymers of isophthalic acid, diethylene glycol, sodium sulfoisophthalic acid;

(A1-2): copolymers of isophthalic acid, terephthalic acid, diethylene glycol, sodium sulfoisophthalic acid.

[ Synthesis of resin (A1) ]

Synthesis example resin (A1-1)

Under the condition of sealing nitrogen in a reactor, 950 parts of dimethyl isophthalate, 1000 parts of diethylene glycol, 0.5 part of zinc acetate and 0.5 part of antimony trioxide are added, and transesterification reaction is carried out at 140-220 ℃ for 3 hours. Then, 30 parts of isophthalic acid-5-sodium sulfonate was added, and after esterification reaction was performed at 220 to 260℃for 1 hour, polycondensation reaction was performed at 240 to 270℃under reduced pressure for 2 hours.

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 to 170℃to homogenize the mixture. Then, 700 parts of water was gradually added with stirring to obtain an aromatic polyester resin (A1-1) as an aqueous emulsion having a nonvolatile content of 20 wt%.

Synthesis example resin (A1-2)

Under the condition that nitrogen is sealed in a reactor, 475 parts of dimethyl isophthalate, 475 parts of dimethyl terephthalate, 1000 parts of diethylene glycol, 0.5 part of zinc acetate and 0.5 part of antimony trioxide are added, and transesterification reaction is carried out at 140-220 ℃ for 3 hours. Then, 30 parts of isophthalic acid-5-sodium sulfonate was added, and after esterification reaction was performed at 220 to 260℃for 1 hour, polycondensation reaction was performed at 240 to 270℃under reduced pressure for 2 hours.

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 to 170℃to homogenize the mixture. Then, 700 parts of water was gradually added with stirring to obtain an aromatic polyester resin (A1-2) as an aqueous emulsion having a nonvolatile content of 20 wt%.

The components used in the comparative examples are shown below.

(a' 3) an aqueous dispersion of an aliphatic polyester (a copolymer of polyethylene oxide glycol (Polyoxyethylene Glycol) and adipic acid);

(A' 4) an aqueous dispersion of bisphenol A-based polyester (maleic anhydride, copolymer of EO4 molar adduct of bisphenol A).

Synthesis example A'3

Under the condition that nitrogen is enclosed in a reactor, 1.0 mol of polyoxyethylene (10 mol) glycol and 2.0 mol of adipic acid are added, and dehydration condensation reaction is carried out at 190 ℃ for 3 hours to obtain an ester compound (A-3). The weight average molecular weight (Mw) was 2840, and the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) was 1.7.

The ester compound (A-3), POE (150) hydrogenated castor oil ether, PO/EO (25/75) polyether (molecular weight 16000) were added to an emulsifying apparatus, and water was slowly added with stirring and phase inversion was performed to obtain an aqueous sizing agent dispersion having a nonvolatile content of 30% by weight.

Synthesis example A'4

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

Unsaturated polyester (A-4), POE (150) hydrogenated castor oil ether, PO/EO (25/75) polyether (molecular weight 16000) were added to an emulsifying apparatus, and water was slowly added with stirring and phase inversion was performed to obtain an aqueous sizing agent dispersion having a nonvolatile content of 30% by weight.

[ production of aqueous Dispersion of Compound (A2) ]

PREPARATION EXAMPLE A2-1

A composition comprising bisphenol a diglycidyl ether acrylic acid adduct/ethylene oxide 150mol addition hydrogenated castor oil ether=80/20 (weight ratio) was added to an emulsifying apparatus, water was slowly added with stirring and phase inversion emulsified to give a homogeneous aqueous dispersion A2-1 of bisphenol a diglycidyl ether acrylic acid adduct. The nonvolatile content of the aqueous dispersion A2-1 was 40% by weight.

The average particle diameter of the aqueous dispersion A2-1 was measured and found to be 0.19. Mu.m. In addition, the aqueous dispersion A2-1 was not subjected to coagulation separation and floating separation at all even when left at 50℃for 1 month, and was excellent in the stability at rest.

PREPARATION EXAMPLE A2-2

An aqueous dispersion A2-2 of an ethylene oxide 4mol addition bisphenol A acrylic acid adduct was obtained in the same manner as in production example A2-1, except that in production example A2-1, an ethylene oxide 4mol addition bisphenol A acrylic acid adduct was used instead of the bisphenol A diglycidyl ether acrylic acid adduct. The nonvolatile content of aqueous dispersion A2-2 was 40% by weight.

The average particle diameter of the aqueous dispersion A2-2 was measured and found to be 0.25. Mu.m. In addition, the aqueous dispersion A2-2 was not subjected to coagulation separation and floating separation at all even when left at 50℃for 1 month, and was excellent in the stability at rest.

PREPARATION EXAMPLES A2-3

A composition comprising 150mol of 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) of 2-acryloyloxyethyl-2-hydroxyethyl-phthalate was added to an emulsifying device, water was slowly added with stirring and phase-inverted emulsified to give a homogeneous aqueous dispersion A2-3 of 2-acryloyloxyethyl-2-hydroxyethyl-phthalate. The nonvolatile content of aqueous dispersion A2-3 was 40% by weight.

The average particle diameter of the aqueous dispersion A2-3 was measured and found to be 0.29. Mu.m. In addition, the aqueous dispersion A2-3 was not subjected to coagulation separation and floating separation at all even when left at 50℃for 1 month, and was excellent in the stability at rest.

PREPARATION EXAMPLES A2-4

A composition comprising trimethylolpropane trimethacrylate/oxyethylene-oxypropylene block polymer (weight average molecular weight 15000, oxypropylene/oxyethylene=20/80 (weight ratio))/oxyethylene-oxypropylene block polymer (weight average molecular weight 2000, oxypropylene/oxyethylene=60/40 (weight ratio))=70/15/15 (weight ratio) was fed into an emulsifying device, and water was slowly added with stirring and phase-inverted emulsified to obtain a uniform aqueous dispersion A2-4 of trimethylolpropane trimethacrylate. The nonvolatile constituents of the aqueous dispersions A2 to 4 were 40% by weight.

The average particle diameter of the aqueous dispersion A2-4 was measured and found to be 0.21. Mu.m. In addition, the aqueous dispersions A2 to 4 were not subjected to coagulation separation and floating separation at all even when left at 50℃for 1 month, and were excellent in the stability at rest.

The components used in the examples or comparative examples are shown below.

(B1) The method comprises the following steps POE (8) bisphenol A ether (BA-8 glycidol: manufactured by Japanese emulsifier Co., ltd.);

(B2) The method comprises the following steps POE (10) bisphenol A ether (BA-10 glycidol: manufactured by Japanese emulsifier Co., ltd.);

(B3) The method comprises the following steps POE (17.5) bisphenol A ether (Blaunon (registered trademark) BEO-17.5: manufactured by Qinghai oil industries Co., ltd.);

(B' 4) POE distyrenated phenyl ether (Emulgen (registered trademark) A-500).

The components used in the examples or comparative examples are shown below.

(C1) The method comprises the following steps 20 molar adducts of ethylene oxide of 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol;

(C2) The method comprises the following steps Ethylene oxide 5 molar adduct of 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol;

(C3) The method comprises the following steps 3, 6-dimethyl-4-octyne-3, 6-diol;

(C4) The method comprises the following steps 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol.

The components used in the examples or comparative examples are shown below.

(D1) The method comprises the following steps An aqueous dispersion of an epoxy resin.

Production example D1

The composition containing jER1001 (Mitsubishi chemical corporation, solid bisphenol A type epoxy resin, epoxy equivalent 450-500)/jER 828 (Mitsubishi chemical corporation, liquid bisphenol A type epoxy resin, epoxy equivalent 184-194)/POE (150) hydrogenated castor oil ether=40/40/20 (weight ratio) was added to an emulsifying apparatus, and water was slowly added with stirring and phase inversion was performed to obtain an aqueous dispersion (D1) of an epoxy resin having a nonvolatile content of 30% by weight.

(E1) The method comprises the following steps Mixed wax emulsions (40%) of oxidized polyethylene wax, beeswax, carnauba wax, paraffin wax.

TABLE 1

TABLE 2

TABLE 3

TABLE 4

TABLE 5

As is clear from tables 1 to 4, the sizing agent of the examples contains the compound (A) and the compound (B) represented by the general formula (1), and the compound (A) contains at least 1 selected from the group consisting of the specific aromatic polyester resin (A1) and the specific compound (A2) having an ethylenically unsaturated group, and contains the compound (A) in a specific amount, so that the problems of the present application can be solved.

In particular, examples 15 to 18 containing the alkyne-based surfactant (C) were excellent in uniform adhesion.

On the other hand, as shown in table 5, the problems could not be solved in the case of not containing the compound (B) (comparative examples 1, 2, 3, 7, 8), in the case of not containing the compound (B) shown by the general formula (1) (comparative example 3) although being an aromatic surfactant, in the case of not containing the aromatic polyester resin (A1) (comparative example 4), and in the case of not containing the aromatic polyester resin but having different structural units (comparative examples 5, 6).

Industrial applicability

Fiber-reinforced composite materials in which matrix resins are reinforced with reinforcing fibers are used for automotive applications, aerospace applications, sports and leisure applications, general industrial applications, and the like. The reinforcing fibers include various inorganic fibers such as carbon fibers, glass fibers, and ceramic fibers, and various organic fibers such as aramid fibers, polyamide fibers, and polyethylene fibers.

Claims (5)

1. A sizing agent for reinforcing fibers comprising a compound A and a compound B represented by the following general formula (1),

the compound A contains at least 1 selected from aromatic polyester resin A1 and compound A2 with ethylenic unsaturated group,

the aromatic polyester resin A1 is a polyester resin comprising the following structural unit I and structural unit II as structural units,

the ethylenically unsaturated group is at least 1 selected from the group consisting of a vinyl ester group, an acrylate group and a methacrylate group,

the weight ratio of the compound A in the nonvolatile components of the sizing agent for the reinforced fiber is more than 10 percent;

structural unit I: structural units formed of at least 1 selected from the group consisting of 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,

structural unit II: structural units formed from polyalkylene glycols,

in the formula (1), R ¹ R is R ² Each independently is 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.

2. The sizing agent for reinforcing fibers according to claim 1, wherein,

the ratio A/B of the weight ratio of the compound A to the compound B is 0.1 to 9.0.

3. The sizing agent for reinforcing fibers according to claim 1 or 2, wherein,

and m and m+n are 8-60.

4. A reinforcing fiber strand obtained by adhering the sizing agent for reinforcing fibers according to any one of claims 1 to 3 to a raw reinforcing fiber strand.

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