Sizing agent for fibers and application thereof

Abstract

Provided are: a sizing agent for fibers, which is capable of imparting excellent adhesion to a matrix resin to a fiber precursor for reinforcing the matrix resin; a fiber precursor using the sizing agent for fibers; and a fiber-reinforced composite material. This sizing agent for fibers contains a compound (A) and a compound (B) having a five-membered ring structure containing a sulfur atom and a nitrogen atom, wherein the compound (A) is at least one type selected from the group consisting of thermosetting resins (A1), thermoplastic resins (A2), and rubbers (A3).

Description

Technical Field

[0001] The present invention relates to a sizing agent for fibers and its uses. More specifically, it relates to a sizing agent for fibers, a method for manufacturing fibers coated with the sizing agent, a fiber filament coated with the sizing agent, and a fiber-reinforced composite material. Background Art

[0002] Fiber-reinforced composite materials in which plastic materials (also referred to as matrix resins) are reinforced with various synthetic fibers are widely used in motor vehicle applications, aerospace applications, sports and leisure applications, general industrial applications, etc. Examples of 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 manufactured in the form of filaments, and then processed through, for example, a hot melt method, a roller winding method, etc. into a sheet-like intermediate material called a unidirectional prepreg, or processed through a filament winding molding method, or processed into various higher-order processed forms such as a fabric or a chopped fiber shape as appropriate, and are used as reinforcing fibers, for example.

[0003] Thermosetting resins, thermoplastic resins, etc. are widely used as the matrix resins of fiber-reinforced composite materials.

[0004] In order to improve the mechanical strength of fiber-reinforced composite materials, the adhesiveness between the matrix resin and the fiber is very important, and sizing agents that can improve the adhesiveness of fibers with respect to matrix resins such as thermosetting resins and thermoplastic resins have been proposed (for example, Patent Documents 1, 2, etc.).

[0005] However, when using conventional sizing agents, the adhesiveness between the matrix resin and the fiber is insufficient, and there are cases where the properties of the obtained composite material do not reach a satisfactory level. There is a strong desire for a sizing agent that can impart excellent adhesiveness with the matrix resin to the fiber.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Laid-Open No. 53-52796

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

[0010] Problems to be Solved by the Invention

[0011] An object of the present invention is to provide a sizing agent for fibers, a fiber filament, and a fiber-reinforced composite material that can impart excellent adhesiveness with a matrix resin to a fiber filament for reinforcing a matrix resin.

[0012] Means for Solving the Problems

[0013] The inventors of the present invention have conducted in-depth studies to solve the above problems, and as a result, it has been found that a sizing agent for fibers containing a specific compound (A) and a specific compound (B) can solve the above problems.

[0014] That is, the sizing agent for fibers of the present invention includes the following embodiments.

[0015] <1>A sizing agent for fibers, which contains a compound (A) and a compound (B) having a 5-membered ring structure containing a sulfur atom and a nitrogen atom, and the above compound (A) is at least one selected from a thermosetting resin (A1), a thermoplastic resin (A2), and a rubber (A3).

[0016] <2>The sizing agent for fibers according to <1>, wherein the above compound (B) includes at least one selected from the compounds represented by the following general formula (1) and the compounds represented by the following general formula (2).

[0017]

[0018] (In formula (1), R 1 is an alkyl group, an aralkyl group, or a hydrogen atom having 1 to 12 carbon atoms, and X and Y are independently a hydrogen atom or a halogen atom)

[0019]

[0020] (In formula (2), R 2 is an alkyl group having 1 to 8 carbon atoms or a hydrogen atom)

[0021] <3>The sizing agent for fibers according to <1> or <2>, wherein the weight ratio of the above compound (B) in the non-volatile components of the above sizing agent is 5 ppm to 10,000 ppm.

[0022] <4>The sizing agent for fibers according to any one of <1> to <3>, wherein the above thermosetting resin (A1) is at least one selected from an epoxy resin, a vinyl ester resin, an unsaturated polyester resin, and a phenolic resin, and the above thermoplastic resin (A2) is at least one selected from a polyurethane resin, a saturated polyester resin, a polyolefin resin, a polyamide resin, a polyether ether ketone resin, a fluororesin, a phenoxy resin, a polybismaleimide resin, a polyimide resin, a polyethersulfone resin, and a polyether ester resin.

[0023] <5>The sizing agent for fibers according to any one of <1> to <4>, which further contains a surfactant (C).

[0024] <6>The sizing agent for fibers according to <5>, wherein the weight ratio of the above surfactant (C) in the non-volatile components of the above sizing agent is 1 wt% to 50 wt%.

[0025] <7>The sizing agent for fibers according to any one of <1> to <6>, wherein the weight ratio of the above compound (A) in the non-volatile components of the sizing agent for fibers is 50% by weight to 99% by weight.

[0026] <8>A method for manufacturing a fiber with a sizing agent attached thereto, which includes a step of attaching the sizing agent for fibers according to any one of <1> to <7> to the fibers.

[0027] <9>A fiber roving with a sizing agent attached thereto, to which the sizing agent for fibers according to any one of <1> to <7> is attached.

[0028] <10>A fiber-reinforced composite material, which contains a matrix resin and the fiber roving with a sizing agent attached thereto as described in <9>.

[0029] Advantages of the Invention

[0030] The sizing agent for fibers of the present invention can impart excellent adhesiveness to the matrix resin to the fibers. The adhesiveness between the fiber roving of the present invention and the matrix resin is excellent. By using the fiber roving of the present invention, a fiber-reinforced composite material having excellent physical properties can be obtained. Detailed Description of the Invention

[0031] Each component of the sizing agent for fibers of the present invention will be described in detail.

[0032] [Compound (A)]

[0033] The sizing agent for fibers of the present invention contains compound (A). Compound (A) is at least one selected from a thermosetting resin (A1), a thermoplastic resin (A2), and a rubber (A3). One kind of compound (A) can be used, or two or more kinds can be used in combination.

[0034] The reason for the sizing agent for fibers of the present invention to improve the adhesiveness to the matrix resin by containing at least one selected from a curable resin (A1), a thermoplastic resin (A2), and a rubber (A3) is considered as follows. That is, by uniformly covering the fiber surface with compound (A), an appropriate polarity can be imparted to the entire fiber surface, and the affinity with the matrix resin can be improved.

[0035] When the matrix resin of the fiber-reinforced composite material is a thermosetting resin, if compound (A) contains a thermosetting resin (A1), it is preferable in terms of further improving the adhesiveness to the matrix resin. When the matrix resin of the fiber-reinforced composite material is a thermoplastic resin, if compound (A) contains a thermoplastic resin (A2), it is preferable in terms of further improving the adhesiveness to the matrix resin.

[0036] Examples of the thermosetting resin (A1) include epoxy resins, vinyl ester resins, unsaturated polyester resins, and phenolic resins. Among these, at least one selected from epoxy resins, vinyl ester resins, and unsaturated polyester resins is preferred, and from the aspect of further exerting the effects of the present application, at least one selected from epoxy resins and unsaturated polyester resins is more preferred. These resins may be used singly or in combination of two or more. These thermosetting resins (A1) may be those known in the art.

[0037] The thermoplastic resin (A2) is preferably at least one selected from polyurethane resins, saturated polyester resins, polyolefin resins, polyamide resins, polyetheretherketone resins, fluororesins, phenoxy resins, polybismaleimide resins, polyimide resins, polyethersulfone resins, and polyetherester resins, more preferably at least one selected from aromatic polyurethane resins, saturated polyester resins, and polyolefin resins, and from the aspect of further exerting the effects of the present application, at least one selected from saturated polyester resins and polyolefin resins is further preferred. These resins may be used in combination of two or more. These thermoplastic resins (A2) may be those known in the art.

[0038] The rubber (A3) is preferably at least one selected from silicone rubbers and diene rubbers, and from the aspect of further exerting the effects of the present application, diene rubbers are more preferred among these. These resins may be used in combination of two or more. These rubbers (A3) may be those known in the art.

[0039] 〔Epoxy resin〕

[0040] Epoxy resin refers to a compound having two or more reactive epoxy groups in its molecular structure. As representatives of epoxy resins, glycidyl ether type obtained from epichlorohydrin and active hydrogen compounds can be cited. In addition, glycidyl ester type, glycidyl amine type, alicyclic type, etc. can be cited. Epoxy resins may be used singly or in combination of two or more.

[0041] The epoxy equivalent of the epoxy resin is not particularly limited, and is preferably 100 to 1500 g / eq. If the epoxy equivalent is within the above range, the change over time of the fiber tow can be suppressed while taking into account the adhesiveness to the matrix resin. The upper limit of the epoxy equivalent is more preferably 1000 g / eq, further preferably 800 g / eq, and particularly preferably 700 g / eq. On the other hand, the lower limit of the epoxy equivalent is more preferably 120 g / eq, further preferably 150 g / eq, and particularly preferably 170 g / eq. In addition, the epoxy equivalent refers to the epoxy equivalent according to JIS-K7236.

[0042] The weight-average molecular weight of the epoxy resin is not particularly limited, and is preferably 100 to 10,000 from the viewpoint of good heat resistance. The lower limit of the average molecular weight is more preferably 150, and further preferably 200. On the other hand, the upper limit of the average molecular weight is more preferably 8,000, and further preferably 7,000.

[0043] Examples of the epoxy resin include aliphatic epoxy resins and aromatic epoxy resins. From the viewpoint of improving the wettability of the matrix resin, aromatic epoxy resins having an aromatic ring in the molecular structure are preferred.

[0044] Examples of the above aromatic epoxy resins include polyglycidyl ether compounds of mononuclear polyphenol compounds such as hydroquinone, resorcinol, and catechol; polyglycidyl ether compounds of polynuclear polyphenol compounds such as dihydroxynaphthalene, biphenol, bisphenol F, bisphenol A, phenol novolac, o-cresol novolac, resorcinol novolac, bisphenol F novolac, bisphenol A novolac, dicyclopentadiene-modified phenol, triphenylmethane, and tetraphenylethane.

[0045] Among these aromatic epoxy resins, compounds represented by the following general formula (3) are preferred from the viewpoint of the effects of this application.

[0046]

[0047] (In formula (3), R 3 , R 4 , R 5 and R 6 are each independently a hydrogen atom or a methyl group)

[0048] p is an integer of 0 to 30, and is preferably 0 to 20, more preferably 0 to 10, from the viewpoint of improving the wettability of the matrix resin.

[0049] The method for producing the above epoxy resin is not particularly limited, and a known method can be adopted. In addition, the above epoxy resin is usually commercially available, and these commercially available epoxy resins can be used in the sizing agent for carbon fiber of the present invention.

[0050] [Vinyl ester resin]

[0051] The vinyl ester resin is a compound having at least one selected from a vinyl ester group, an acrylate group, and a methacrylate group. One kind or two or more kinds of vinyl ester resins can be used. In addition, 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-".

[0052] Examples of the vinyl ester resin include, for example, alkyl (meth)acrylate, alkoxy polyalkylene glycol (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-hydroxyalkyl (meth)acrylate, dialkylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2-methacryloyloxyethyl 2-hydroxypropyl phthalate, polyalkylene glycol di(meth)acrylate, alkanediol di(meth)acrylate, glycerol di(meth)acrylate, 2-hydroxy-3-acryloyloxypropyl (meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, bisphenol A (meth)acrylate, alkylene oxide adduct bisphenol A (meth)acrylate, bisphenol A diglycidyl ether (meth)acrylate adduct, alkylene oxide adduct bisphenol A diglycidyl ether (meth)acrylate adduct, trimethylolpropane tri(meth)acrylate, glycidyl (meth)acrylate, phenoxyalkyl (meth)acrylate, phenoxy polyalkylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, polyalkylene glycol nonylphenyl ether (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, neopentyl glycol (meth)acrylate benzoate, alkylene oxide adduct trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, pentaerythritol tri(meth)acrylate hexamethylene diisocyanate urethane prepolymer, and the like.

[0053] Among these, from the viewpoint of excellent adhesiveness to the matrix resin, the vinyl ester resin preferably has at least one selected from oxyalkylene and aryl, and more preferably contains aryl. 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 benzoate, bisphenol A (meth)acrylate, alkylene oxide adduct bisphenol A (meth)acrylate, bisphenol A diglycidyl ether (meth)acrylate adduct, alkylene oxide adduct bisphenol A diglycidyl ether (meth)acrylate adduct are preferred, polyalkylene glycol di(meth)acrylate, bisphenol A (meth)acrylate, alkylene oxide adduct bisphenol A (meth)acrylate, bisphenol A diglycidyl ether (meth)acrylate adduct, alkylene oxide adduct bisphenol A diglycidyl ether (meth)acrylate adduct are more preferred, and bisphenol A (meth)acrylate, alkylene oxide adduct bisphenol A (meth)acrylate, bisphenol A diglycidyl ether (meth)acrylate adduct, alkylene oxide adduct bisphenol A diglycidyl ether (meth)acrylate adduct are particularly preferred.

[0054] [Unsaturated polyester resin]

[0055] The unsaturated polyester resin is not particularly limited as long as it is a polyester resin having a carbon-carbon double bond and is a resin other than the above-mentioned vinyl ester resin. Examples thereof include unsaturated polyesters obtained by reacting an acid component containing an α,β-unsaturated dicarboxylic acid with an alcohol. Examples of the α,β-unsaturated dicarboxylic acid include maleic acid, fumaric acid, itaconic acid, etc., and derivatives such as acid anhydrides thereof, and two or more of these can be used in combination. In addition, according to need, an α,β-unsaturated dicarboxylic acid can be used in combination with saturated dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, adipic acid, sebacic acid, etc., which are acid components other than the α,β-unsaturated dicarboxylic acid, and derivatives such as acid anhydrides thereof. Examples of the alcohol include aliphatic diols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,2-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, etc., alicyclic diols such as cyclopentanediol, cyclohexanediol, etc., aromatic diols such as hydrogenated bisphenol A, bisphenol A propylene oxide (1 to 100 moles) adduct, xylene glycol, etc., polyhydric alcohols such as trimethylolpropane, pentaerythritol, etc., and two or more of these can be used in combination.

[0056] Among the unsaturated polyester resins, aromatic unsaturated polyester resins are preferred because of their excellent adhesiveness to the matrix resin. Among the aromatic unsaturated polyester resins, condensates of fumaric acid or maleic acid with ethylene oxide (hereinafter simply referred to as EO) adducts of bisphenol A, condensates of fumaric acid or maleic acid with propylene oxide (hereinafter simply referred to as PO) adducts of bisphenol A, and condensates of fumaric acid or maleic acid with EO and PO adducts of bisphenol A (the addition of EO and PO can be random or block) are more preferred.

[0057] From the aspect of good heat resistance, the weight average molecular weight of the unsaturated polyester resin is preferably 1000 to 12000. The upper limit of the weight average molecular weight is more preferably 8000, and further preferably 7000. On the other hand, the lower limit of the weight average molecular weight is more preferably 1500, and further preferably 2000. The acid value is preferably 5 KOHmg / g or less, and preferably 0 KOHmg / g or more.

[0058] [Phenolic resin]

[0059] Examples of phenolic resins include resins obtained by condensation of phenolic compounds such as phenol, cresol, xylenol, tert-butylphenol, nonylphenol, cashew nut oil, lignin, resorcinol, catechol, etc. with aldehydes such as formaldehyde, acetaldehyde, furfural, etc. Examples also include novolac resins, resol resins, etc. Novolac resins can be obtained by reacting phenol and aldehyde in the presence of an acid catalyst such as oxalic acid under conditions where the amounts are the same or phenol is in excess. Resol resins can be obtained by reacting phenol and aldehyde in the presence of a base catalyst such as sodium hydroxide, ammonia, or an organic amine under conditions where the amounts are the same or aldehyde is in excess.

[0060] 〔Polyurethane resin〕

[0061] Urethane-based resins can be obtained by the reaction of polyisocyanates, polyols, and, if necessary, chain extenders.

[0062] Examples of polyisocyanates include aliphatic diisocyanates such as hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, etc.; alicyclic diisocyanates such as 1,4-cyclohexane diisocyanate, isophorone diisocyanate, etc.; aromatic diisocyanates such as phenylene diisocyanate, toluene diisocyanate, diphenylmethane-4,4'-diisocyanate, etc.; and araliphatic diisocyanates such as xylene diisocyanate, etc. As polyisocyanates, compounds in which an alkyl group (e.g., methyl) is substituted in the main chain or the ring can be used.

[0063] Examples of polyols include polyester diols (aliphatic dicarboxylic acid components having 4 to 12 carbon atoms such as fumaric acid, maleic acid, itaconic acid, succinic acid, adipic acid, azelaic acid, sebacic acid; aromatic dicarboxylic acid components such as phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, phthalic anhydride; C2-12 aliphatic diol components such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol; polyester diols obtained from lactone components having 4 to 12 carbon atoms such as ε-caprolactone, etc.), polyether diols (polyethylene glycol, polypropylene glycol, polyoxyethylene / polyoxypropylene block copolymer, polyoxytetramethylene glycol, bisphenol A-alkylene oxide adduct, etc.), polyester ether diols (polyester diols using the above polyether diols as part of the diol components), etc.

[0064] In addition, as a chain extender, in addition to alkylene diols having 2 to 10 carbon atoms such as ethylene glycol and propylene glycol, diamines and the like can be cited. As diamines, for example, straight-chain or branched alkylene diamines having about 2 to 10 carbon atoms such as ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, trimethylhexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, etc., aliphatic diamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenetriamine and other straight-chain or branched polyalkylene polyamines; alicyclic diamines such as isophoronediamine, bis(4-amino-3-methylcyclohexyl)methane, bis(aminomethyl)cyclohexane; aromatic diamines such as phenylenediamine, xylenediamine, diaminodiphenylmethane, etc.

[0065] Among polyurethane resins, from the aspect of being able to balance heat resistance and adhesion to the matrix resin, aromatic polyurethane resins are preferred, and aromatic polyester-based polyurethane resins are more preferred.

[0066] [Saturated polyester resin]

[0067] As saturated polyester resins, for example, aliphatic polyester resins, aromatic polyester resins, etc. can be cited. As saturated polyester resins, since heat resistance and adhesion to the matrix resin can be balanced, polyalkylene arylate resins or aromatic polyester resins are preferred, and aromatic polyester resins are more preferred.

[0068] As aromatic polyester resins, for example, alkylene di-esters of terephthalic acid having 2 to 4 carbon atoms such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), etc.; alkylene di-esters of naphthalenedicarboxylic acid having 2 to 4 carbon atoms corresponding to the above-mentioned dialkyl terephthalates (for example, polyethylene naphthalate, etc.); 1,4-cyclohexanedimethanol terephthalate (PCT), etc. The aromatic polyester resin can be a copolyester containing alkylene arylate units as the main component (for example, 50% by weight or more), and the copolymerization components can include alkylene diols having 2 to 6 carbon atoms such as ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, etc., polyalkylene diols having 2 to 4 carbon atoms, asymmetric aromatic dicarboxylic acids such as phthalic acid, isophthalic acid or their acid anhydrides, aliphatic dicarboxylic acids such as adipic acid, etc. In addition, a small amount of polyol and / or polycarboxylic acid can also be used to introduce a branched structure into the linear polyester.

[0069] In addition, a modified polyester resin modified with a modifying compound (for example, an aromatic polyester resin having at least one selected from amino groups and oxyalkylene groups) can also be used. Examples of the modifying compound include polyamines (such as aliphatic diamines such as straight-chain or branched alkylene diamines having about 2 to 10 carbon atoms such as ethylenediamine, trimethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, trimethylhexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane; alicyclic diamines such as isophoronediamine, bis(4-amino-3-methylcyclohexyl)methane, bis(aminomethyl)cyclohexane; aromatic diamines such as phenylenediamine, xylenediamine, diaminodiphenylmethane, etc.), polyols (such as (poly)oxyethylene glycol, (poly)oxytrimethylene glycol, (poly)oxypropylene glycol, (poly)oxytetramethylene glycol, etc., (poly)oxyalkylene glycols having 2 to 4 carbon atoms), etc. Modification can be carried out, for example, by heating and mixing the polyester resin with the modifying compound and using amidation, esterification or transesterification reactions.

[0070] From the aspect of good heat resistance, the weight average molecular weight of the saturated polyester resin is preferably 3000 to 20000. The upper limit of this weight average molecular weight is more preferably 19000, and further preferably 18000. On the other hand, the lower limit of this weight average molecular weight is more preferably 6000, and further preferably 7000.

[0071] [Polyolefin resin]

[0072] As the polyolefin resin, for example, a copolymer of an olefin monomer and a monomer such as an unsaturated carboxylic acid copolymerizable with the olefin monomer can be mentioned, and it can be produced by a known method. The polyolefin resin can be a random copolymer of an olefin monomer and an unsaturated carboxylic acid, or a graft copolymer of an unsaturated carboxylic acid grafted onto an olefin monomer. One kind of polyolefin resin can be used, or two or more kinds can be used.

[0073] Examples of the olefin monomer include ethylene, propylene, 1-butene, etc. These can be used alone or in combination of two or more. Examples of the monomer copolymerizable with the olefin monomer include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, etc. These can be used alone or in combination of two or more.

[0074] Regarding the copolymerization ratio of the above-mentioned olefin monomer and the monomer copolymerizable with the olefin monomer, from the aspect of good adhesiveness to the matrix resin, when the total weight of the copolymer is set to 100% by weight, the olefin monomer is preferably 80 to 99.5% by weight, and the monomer copolymerizable with the olefin monomer is 5 to 20% by weight. More preferably, the olefin monomer is 90 to 99% by weight, and the monomer copolymerizable with the olefin monomer is 1 to 10% by weight. Particularly preferably, the olefin monomer is 95 to 98% by weight, and the monomer copolymerizable with the olefin monomer is 2 to 5% by weight.

[0075] In addition, in the polyolefin resin, from the viewpoint of good storage stability of the emulsion, it is preferable to neutralize modified groups such as carboxyl groups introduced by copolymerization with a basic compound. Examples of the basic compound include metal salts such as sodium hydroxide and potassium hydroxide; ammonia; amines such as laurylamine, ethylenediamine, trimethylamine, dimethylethanolamine, dibutylethanolamine, monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine, and monobutanolamine. Among these, amines are further preferred, and diethanolamine is particularly preferred.

[0076] From the viewpoint of good heat resistance, the weight average molecular weight of the polyolefin resin is preferably 5,000 to 200,000. The upper limit of the weight average molecular weight is more preferably 150,000, and further preferably 130,000. On the other hand, the lower limit of the weight average molecular weight is more preferably 6,000, and further preferably 7,000.

[0077] 〔Silicone rubber〕

[0078] Examples of the silicone rubber include addition-curable silicone resins, self-crosslinking silicone resins, silicone rubber film-forming silicone resin components, and silicone rubber powders. Silicone rubbers that preferably form a film by heating, reaction, etc. are preferred. One kind or two or more kinds of silicone rubbers can be used.

[0079] Examples of the addition-curable silicone resin include room temperature curable silicone rubber (RTV silicone rubber), low temperature curable silicone rubber (LTV silicone rubber), and silicone resin components of an O / W type emulsion obtained by emulsifying a reactive silicone with an emulsifier. Among these, in order to further exhibit the effects of the present invention, a room temperature curable silicone rubber (RTV silicone rubber) or an aqueous dispersion of a silicone resin obtained by emulsifying a reactive silicone is preferred, and those that can form a silicone rubber film by drying the aqueous dispersion are more preferred.

[0080] 〔Diene rubber〕

[0081] The diene rubber is not particularly limited as long as it is a polymer containing a polymerizable monomer having a conjugated diene structure as a constituent unit. Examples of the polymerizable monomer having a conjugated diene structure include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, and 1,3-pentadiene.

[0082] As specific examples of the diene rubber, butadiene polymers, isoprene polymers, styrene / butadiene copolymers, acrylonitrile / butadiene copolymers, acrylonitrile / isoprene copolymers, acrylonitrile / butadiene / isoprene copolymers, methacrylonitrile / butadiene copolymers, methacrylonitrile / isoprene copolymers, methacrylonitrile / butadiene / isoprene copolymers, acrylonitrile / methacrylonitrile / butadiene copolymers, acrylonitrile / butadiene / methyl acrylate copolymers, acrylonitrile / butadiene / acrylic acid copolymers, acrylonitrile / butadiene / methacrylic acid copolymers, acrylonitrile / butadiene / n-butyl acrylate copolymers, acrylonitrile / butadiene / n-butyl acrylate / mono-n-butyl itaconate copolymers, etc. can be cited. Among them, from the aspect of excellent heat resistance, styrene / butadiene copolymers are preferred. The diene rubber can be a water dispersion or can form a film by drying the water dispersion.

[0083] [Compound (B) having a 5-membered ring structure containing a sulfur atom and a nitrogen atom]

[0084] The sizing agent of the present invention contains a compound (B) having a 5-membered ring structure containing a sulfur atom and a nitrogen atom (hereinafter referred to as compound (B)).

[0085] As long as compound (B) is a compound having a 5-membered ring structure containing a sulfur atom and a nitrogen atom, there is no particular limitation. From the viewpoint of improving the adhesiveness to the matrix resin, if there is a bond between heteroatoms in the 5-membered ring, the adhesiveness at the interface between compound (A) and the matrix resin can be improved, and the physical properties of the composite material can be improved. Therefore, it is preferred. If there is a nitrogen-sulfur bond in the 5-membered ring, the adhesiveness can be further improved, and the physical properties of the composite material can be improved. Therefore, it is preferred. If it contains at least one selected from the compounds represented by the following general formula (1) and the following general formula (2), the adhesiveness can be further improved, and the physical properties of the composite material can be improved. Therefore, it is particularly preferred.

[0086] Regarding the reason for improving the adhesiveness by compound (B), it is considered that compound (B) exists at the interface between the sizing agent and the matrix resin, improving the compatibility and reactivity between the sizing agent components and the matrix resin. That is, by improving the compatibility, the matrix resin can be sufficiently infiltrated into the fiber bundle, and by improving the reactivity, the sizing agent components and the matrix resin can be firmly chemically bonded. Through these effects, the adhesiveness to the matrix resin is improved. Moreover, if there is a nitrogen-sulfur bond, this effect is further promoted, and if it is a compound represented by the following general formula (1) and the following general formula (2), this effect is particularly promoted.

[0087] Compound (B) can contain one kind or two or more kinds. From the aspect of excellent adhesiveness to the matrix resin, it is more preferably contained in two or more kinds.

[0088]

[0089] In formula (1), from the aspect of achieving the effects of the present application, R is preferably 1 an alkyl group, aralkyl group having 1 to 12 carbon atoms or a hydrogen atom, and X and Y are each independently a hydrogen atom or a halogen atom.

[0090] R 1 is more preferably an alkyl group, aralkyl group having 1 to 10 carbon atoms or a hydrogen atom, and particularly preferably an alkyl group having 1 to 8 carbon atoms or a hydrogen atom.

[0091] As specific examples of R 1 there may be mentioned, for example, methyl, ethyl, isopropyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, phenyl and hydrogen atom. From the viewpoint of compatibility with compound (A), methyl, ethyl, isopropyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl and hydrogen atom are more preferable, and methyl, ethyl, isopropyl, propyl, butyl, pentyl, hexyl, heptyl, octyl and hydrogen atom are particularly preferable.

[0092] In formula (1), X and Y are more preferably each independently a hydrogen atom, a chlorine atom or a bromine atom, and still more preferably a hydrogen atom or a chlorine atom.

[0093] When at least one of X and Y is a hydrogen atom, from the viewpoint of compatibility with compound (A), R 1 is more preferably methyl, ethyl, isopropyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl and hydrogen atom, and still more preferably methyl, ethyl, isopropyl, propyl, butyl, pentyl, hexyl, heptyl, octyl and hydrogen atom.

[0094]

[0095] In formula (2), from the aspect of achieving the effects of the present application, R 2 is preferably an alkyl group having 1 to 8 carbon atoms or a hydrogen atom, more preferably an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and particularly preferably an alkyl group having 1 to 4 carbon atoms.

[0096] As specific examples of R 2 there may be mentioned, for example, methyl, ethyl, isopropyl, propyl, butyl, pentyl, hexyl, heptyl, octyl and hydrogen atom. From the viewpoint of compatibility with compound (A), methyl, ethyl, isopropyl, propyl, butyl, pentyl, hexyl and hydrogen atom are more preferable, and methyl, ethyl, isopropyl, propyl, butyl and hydrogen atom are particularly preferable.

[0097] As compound (B), in addition to the compounds represented by general formula (1) and general formula (2), thiazoles, thiadiazoles and the like can be mentioned.

[0098] As thiazoles, 4-bromothiazole, 4-methylthiazole, 2,4-dichlorothiazole, 2-methyl-4-methylthiazole, 2-isopropyl-4-methylthiazole, 2-methyl-4-methylthiazole, 2-mercaptothiazole, 2-aminothiazole, 2-methylthiazole, 2-ethylthiazole, 2-propionylthiazole, 2-acetylthiazole, 5-methylthiazole, 2,5-dibromothiazole, and 5-(2-hydroxyethyl)-4-methylthiazole can be mentioned.

[0099] As thiadiazoles, 2-amino-1,3,4-thiadiazole, 1,3,4-thiadiazole-2-thiol, 1,3,4-thiadiazole-2,5-diamine, 2-amino-5-mercapto-1,3,4-thiadiazole, and 5-methyl-1,3,4-thiadiazole-2-thiol can be mentioned.

[0100] The sizing agent for fibers of the present invention may further contain a derivative of compound (B) as other components. As the derivative of compound (B), reaction products of compound (B) with nucleophilic compounds, etc. can be mentioned.

[0101] As the nucleophilic compound, for example, a compound having at least one selected from a thiol group, an amino group, and an alkoxy group can be mentioned. Specifically, organic thiol compounds, organic amine compounds, organic alcohol compounds, and amino acid compounds, etc. can be mentioned. As the organic groups thereof, alkyl groups, alkenyl groups, aryl groups, etc. can be mentioned.

[0102] [Surfactant (C)]

[0103] From the aspect of improving the wettability of the matrix resin, the sizing agent for fibers of the present invention preferably contains surfactant (C). Surfactant (C) is not particularly limited as long as it is at least one selected from nonionic surfactants, anionic surfactants, and cationic surfactants. It preferably contains at least one selected from nonionic surfactants and anionic surfactants, and more preferably contains a nonionic surfactant.

[0104] As nonionic surfactants, for example, ether-type nonionic surfactants, polyol fatty acid ester-type nonionic surfactants, polyoxyalkylene polyol fatty acid ester-type nonionic surfactants, alkylamide-type nonionic surfactants, polyoxyalkylene fatty acid amide-type nonionic surfactants, etc. can be mentioned.

[0105] Examples of the ether-type nonionic surfactants include polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether, and 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 triphenylethylene phenyl ether, polyoxyethylene stilbene phenyl ether, polyoxyethylene styrene phenyl ether, polyoxyethylene tribenzyl phenyl ether, polyoxyethylene dibenzyl phenyl ether, and polyoxyethylene benzyl phenyl ether; ethylene oxide / propylene oxide block or random copolymers; terminal sucrose etherified products of ethylene oxide / propylene oxide block or random copolymers; polyoxyethylene and / or polyoxypropylene adducts of bisphenol A, etc.

[0106] Examples of the polyol fatty acid ester-type nonionic surfactants include sorbitan esters such as sorbitan monopalmitate and sorbitan monooleate; glycerol fatty acid esters such as glycerol monostearate, glycerol monolaurate, and glycerol monopalmitate; sucrose fatty acid esters, etc.

[0107] Examples of the polyoxyalkylene polyol fatty acid ester-type nonionic surfactants include polyoxyalkylene fatty acid esters such as polyoxyethylene monolaurate, polyoxyethylene monooleate, polyoxyethylene monostearate, polyoxyethylene monomyristate, polyoxyethylene dilaurate, polyoxyethylene dioleate, polyoxyethylene dimyristate, and polyoxyethylene distearate; polyoxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monostearate and polyoxyethylene sorbitan monooleate; polyoxyalkylene sorbitol fatty acid esters; polyoxyalkylene castor oil ethers such as polyoxyethylene castor oil ether; polyoxyalkylene hydrogenated castor oil ethers such as polyoxyethylene hydrogenated castor oil ether, etc.

[0108] Examples of the alkylamide-type nonionic surfactants include diethanolamine monolauramide, etc.

[0109] Examples of the polyoxyalkylene fatty acid amide-type nonionic surfactants include polyoxyethylene diethanolamine monooleylamide, polyoxyethylene laurylamine, polyoxyethylene tallow amine, etc.

[0110] As the nonionic surfactant, one kind of nonionic surfactant can be used alone, or two or more kinds of nonionic surfactants can be appropriately combined and used. Since the effects of the present invention are excellent, ether-type nonionic surfactants are preferably used among these nonionic surfactants.

[0111] From the viewpoint of exerting the effects of the present application, the weight-average molecular weight of the nonionic surfactant is preferably 1000 to 20000. The upper limit of the weight-average molecular weight is more preferably 18000, further preferably 17000, and particularly preferably 16000. On the other hand, the lower limit of the weight-average molecular weight is more preferably 1500, further preferably 1800, and particularly preferably 2000.

[0112] From the viewpoint of achieving the effects of the present application, the oxyethylene / oxypropylene block or random copolymer is preferably a block copolymer.

[0113] From the viewpoint of achieving the effects of the present application, the average number of moles of ethylene oxide added to the oxyethylene / oxypropylene block or random copolymer is preferably 10 to 500. The upper limit of this average number of moles of addition is more preferably 450, and further preferably 400. On the other hand, the lower limit of this average number of moles of addition is more preferably 30, and further preferably 50.

[0114] From the viewpoint of achieving the effects of the present application, the average number of moles of propylene oxide added to the oxyethylene / oxypropylene block or random copolymer is preferably 1 to 100. The upper limit of this average number of moles of addition is more preferably 80, further preferably 70, and particularly preferably 60. On the other hand, the lower limit of this average number of moles of addition is more preferably 5, further preferably 10, and particularly preferably 15.

[0115] Examples of the anionic surfactant include ether carboxylic acid (salt), ether sulfate ester salt, sulfosuccinate ester salt, (poly)oxyethylene coconut fatty acid monoethanolamide sodium sulfate, sulfonate having an alkyl group, phosphate ester salt having an alkyl group, fatty acid salt, acylated amino acid salt, amine neutralized product of fatty acid, etc.

[0116] Examples of the cationic surfactant include quaternary ammonium salt type and amine salt type cationic surfactants, etc.

[0117] 〔Hydrophilic solvent (D)〕

[0118] From the aspect of improving the compatibility between compound (A) and compound (B), the sizing agent for fibers of the present invention preferably contains a hydrophilic solvent (D).

[0119] The hydrophilic solvent (D) is not particularly limited as long as its solubility in water at 25°C is 0.05 g / ml or more, and it further preferably contains at least one selected from the compounds represented by the following general formula (4) and aprotic nitrogen-containing organic compounds. The hydrophilic solvent (D) can be used singly or in combination of two or more.

[0120]

[0121] In formula (4), AO is an oxyalkylene group having 2 to 4 carbon atoms, and n is an integer of 1 to 3.

[0122] From the aspect of improving the compatibility between compound (A) and compound (B) and making it easier to achieve the effects of the present application, the compound represented by the general formula (4) is preferably selected from at least one of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol, and more preferably selected from at least one of ethylene glycol, diethylene glycol, and propylene glycol. One kind or two or more kinds of the compounds represented by the general formula (4) can be used.

[0123] From the perspective of improving the compatibility between compound (A) and compound (B), the aprotic nitrogen-containing organic compound is preferably selected from at least one of N,N-dimethylformamide, 1-methyl-2-pyrrolidone, N,N-dimethylacetamide, and acetonitrile, and more preferably selected from at least one of 1-methyl-2-pyrrolidone and N,N-dimethylformamide. One kind or two or more kinds of the aprotic nitrogen-containing organic compound can be used.

[0124] 〔Sizing agent for fibers〕

[0125] The sizing agent for fibers of the present invention contains the above-mentioned compound (A) and compound (B).

[0126] From the perspective of improving the adhesiveness to the matrix resin, the weight ratio of compound (A) in the non-volatile components of the sizing agent of the present invention is preferably 20% by weight to 99% by weight. The upper limit of this weight ratio is more preferably 98% by weight, further preferably 97% by weight, and particularly preferably 95% by weight. On the other hand, the lower limit of this weight ratio is more preferably 25% by weight, further preferably 30% by weight, particularly preferably 40% by weight, and optimally 50% by weight. Additionally, for example, it is more preferably 40% by weight to 97% by weight, and further preferably 50% by weight to 95% by weight.

[0127] In addition, the non-volatile components in the present invention are those obtained by the method described in the examples.

[0128] From the perspective of improving the adhesiveness to the matrix resin, the weight ratio of compound (B) in the non-volatile components of the sizing agent of the present invention is preferably 5 ppm to 10,000 ppm. The upper limit of this weight ratio is more preferably 9,000 ppm, further preferably 8,000 ppm, and particularly preferably 7,000 ppm. On the other hand, the lower limit of this weight ratio is more preferably 10 ppm, further preferably 15 ppm, and particularly preferably 17 ppm. Additionally, for example, it is more preferably 15 ppm to 8,000 ppm, and further preferably 17 ppm to 7,000 ppm.

[0129] From the viewpoint of improving the adhesiveness to the matrix resin, the weight ratio of the compound (B) contained in the sizing agent of the present invention to 10,000 parts by weight of the compound (A) is preferably 1 part by weight to 500 parts by weight. In addition, the weights of the compound (A) and the compound (B) refer to the weights of the respective components in the non-volatile components contained in the sizing agent of the present invention. The upper limit of this weight ratio is more preferably 350 parts by weight, further preferably 400 parts by weight, and particularly preferably 450 parts by weight. On the other hand, the lower limit of this weight ratio is more preferably 3 parts by weight, further preferably 4 parts by weight, and particularly preferably 5 parts by weight. In addition, for example, it is more preferably 4 parts by weight to 400 parts by weight, and further preferably 5 parts by weight to 450 parts by weight.

[0130] When the sizing agent for fibers of the present invention contains the surfactant (C), from the viewpoint of improving the adhesiveness to the matrix resin, the weight ratio of the surfactant (C) in the non-volatile components of the sizing agent of the present invention is preferably 1 wt% to 50 wt%. The upper limit of this weight ratio is more preferably 45 wt%, further preferably 40 wt%, and particularly preferably 35 wt%. On the other hand, the lower limit of this weight ratio is more preferably 1 wt%, further preferably 3 wt%, and particularly preferably 5 wt%. In addition, for example, it is more preferably 3 wt% to 40 wt%, and further preferably 5 wt% to 35 wt%.

[0131] When the sizing agent for fibers of the present invention contains the surfactant (C), from the viewpoint of the adhesiveness to the matrix resin, the weight ratio of the compound (A) in the non-volatile components of the sizing agent of the present invention is preferably 1 wt% to 50 wt%. The upper limit of this weight ratio is more preferably 45 wt%, further preferably 40 wt%, and particularly preferably 35 wt%. On the other hand, the lower limit of this weight ratio is more preferably 1 wt%, further preferably 3 wt%, and particularly preferably 5 wt%. In addition, for example, it is more preferably 3 wt% to 40 wt%, and further preferably 5 wt% to 35 wt%.

[0132] When the sizing agent for fibers of the present invention contains the surfactant (C), from the viewpoint of the adhesiveness to the matrix resin, the weight ratio of the surfactant (C) to the total of the compound (A) and the surfactant (C) ((C) / ((A)+(C))) is preferably 0.05 to 0.5. In addition, the weights of the compound (A) and the surfactant (C) refer to the weights of the respective components in the non-volatile components contained in the sizing agent of the present invention. The upper limit of this weight ratio is more preferably 0.45, further preferably 0.4, and particularly preferably 0.3. On the other hand, the lower limit of this weight ratio is more preferably 0.07, further preferably 0.08, and particularly preferably 0.1. In addition, for example, it is more preferably 0.08 to 0.4, and further preferably 0.1 to 0.3.

[0133] When the sizing agent for fibers of the present invention contains a hydrophilic solvent (D), from the viewpoint of improving the adhesion to the matrix resin, the weight ratio of the hydrophilic solvent (D) of the sizing agent of the present invention to 10,000 parts by weight of the non-volatile components is preferably 10 to 1000 parts by weight. The upper limit of this weight ratio is more preferably 900 parts by weight, further preferably 800 parts by weight, and particularly preferably 700 parts by weight. On the other hand, the lower limit of this weight ratio is more preferably 15 parts by weight, further preferably 20 parts by weight, and particularly preferably 30 parts by weight. In addition, for example, it is more preferably 20 to 800 parts by weight, and further preferably 30 to 700 parts by weight.

[0134] The manufacturing method of the sizing agent of the present invention is not particularly limited, and known methods can be adopted. Examples include: a method of putting each component constituting the sizing agent into water under stirring to form an aqueous solution, an emulsion, or a water dispersion; a method of forming an aqueous solution, an emulsion, or a water dispersion when manufacturing each component constituting the sizing agent; a method of putting each component constituting the sizing agent into water containing a surfactant under stirring and emulsifying or dispersing; a method of mixing each component constituting the sizing agent with a pre-emulsified and dispersed emulsion dispersion; a method of mixing each component constituting the sizing agent, heating the obtained mixture to above the softening point, and then applying mechanical shear force using a homogenizer, a homogenizing mixer, a ball mill, etc., and gradually adding water to perform phase inversion emulsification; a method of mixing and emulsifying and dispersing an emulsion dispersion in an oiling bath for imparting the sizing agent, etc.

[0135] The sizing agent of the present invention is preferably self-emulsified and / or emulsified and dispersed in water. When the sizing agent is self-emulsified and / or emulsified and dispersed in water, the average particle size is not particularly limited. From the viewpoint of storage stability, it is preferably 10 μm or less, more preferably 0.01 to 1 μm, and further preferably 0.01 to 0.5 μm. In addition, the average particle size of the present invention is the arithmetic average diameter measured by a laser diffraction / scattering type particle size distribution measuring device (LA-920 manufactured by Horiba).

[0136] 〔Fiber filament and its manufacturing method〕

[0137] The fiber filament of the present invention is obtained by attaching the above-mentioned sizing agent for fibers to a raw material synthetic fiber filament, and can be suitably used as a reinforcing fiber for reinforcing a thermosetting matrix resin or a thermoplastic matrix resin.

[0138] The manufacturing method of the fiber filament of the present invention includes a sizing treatment step, which is a step of attaching the above-mentioned sizing agent for fibers to a raw material synthetic fiber filament and drying the obtained attachment.

[0139] The method for attaching the sizing agent to the raw synthetic fiber filament and obtaining the attachment is not particularly limited, and it can be a method of attaching the sizing agent to the raw synthetic fiber filament by a contact roller method, a roll dipping method, a spraying method, or other known methods. Among these methods, the roll dipping method can uniformly attach the sizing agent to the raw synthetic fiber filament, so it is preferred.

[0140] The drying method of the obtained attachment is not particularly limited. For example, it can be dried by heating with a heating roller, hot air, a hot plate, etc.

[0141] In addition, when the sizing agent for fibers of the present invention is attached to the raw synthetic fiber filament, all the components of the sizing agent for fibers can be mixed and then attached, or the components can be divided into two or more stages and attached. In addition, within the range that does not hinder the effects of the present invention, thermosetting resins such as epoxy resins, vinyl ester resins, unsaturated polyester resins, and phenolic resins, as well as thermoplastic resins such as polyolefin resins, nylon resins, polycarbonate resins, polyester resins, polyacetal resins, ABS resins, phenoxy resins, polymethyl methacrylate resins, polyphenylene sulfide resins, polyetherimide resins, and polyether ketone resins can be attached to the raw synthetic fiber filament.

[0142] The fiber filament of the present invention can be used as a reinforcing fiber for a composite material using various thermosetting resins or various thermoplastic resins as matrix resins, and the use form can be in a state of continuous fiber or in a state of being cut into a specific length.

[0143] The amount of the non-volatile component of the sizing agent for fibers attached to the raw synthetic fiber filament can be appropriately selected as long as it is the necessary amount for the synthetic fiber filament to have the desired function. The attachment amount is preferably 0.1 to 20% by weight based on the raw synthetic fiber filament. In the synthetic fiber filament in a state of continuous fiber, the attachment amount is more preferably 0.1 to 10% by weight, and further preferably 0.5 to 5% by weight based on the raw synthetic fiber filament. In addition, in the filament in a state of being cut into a specific length, it is more preferably 0.5 to 20% by weight, and further preferably 1 to 10% by weight.

[0144] As the synthetic fiber of the fiber sizing agent applicable to the present invention (raw material), various inorganic fibers such as carbon fiber, glass fiber, and ceramic fiber, aramid fiber, polyethylene fiber, polyethylene terephthalate fiber, polybutylene terephthalate fiber, polyethylene naphthalate fiber, polyarylate fiber, polyacetal fiber, PBO fiber, polyphenylene sulfide fiber, polyketone fiber and other various organic fibers can be cited. From the viewpoint of the physical properties of the obtained fiber reinforced composite material, at least 1 kind selected from carbon fiber, aramid fiber, polyethylene fiber, polyethylene terephthalate fiber, polybutylene terephthalate fiber, polyethylene naphthalate fiber, polyarylate fiber, polyacetal fiber, PBO fiber, polyphenylene sulfide fiber and polyketone fiber is preferred, and carbon fiber is further preferred.

[0145] 〔Fiber Reinforced Composite Material〕

[0146] The fiber reinforced composite material of the present invention contains a thermosetting matrix resin or a thermoplastic matrix resin, and the above-mentioned fiber roving. Since the fiber roving is treated with the fiber sizing agent of the present invention, it has good affinity with the fiber roving and the thermoplastic matrix resin, and a fiber reinforced composite material with excellent adhesiveness can be formed.

[0147] The fiber reinforced composite material of the present invention contains a matrix resin and the above-mentioned fiber roving. The fiber roving is treated with the sizing agent of the present invention, and the sizing agent is evenly attached, and has good affinity with the fiber roving and the matrix resin, and a fiber reinforced composite material with excellent adhesiveness can be formed. In addition, the thermal decomposition of the sizing agent during high-temperature treatment can be suppressed, and the adhesion hindrance to the matrix resin caused by thermal decomposition can be suppressed. Here, the matrix resin refers to a resin containing at least 1 kind selected from thermosetting resins and thermoplastic resins, and may contain 1 kind or 2 or more kinds, and there is no particular limitation. Examples include epoxy resin, phenolic resin, unsaturated polyester resin, vinyl ester resin, cyanate ester resin, polyimide resin, etc. As the thermoplastic resin, there is no particular limitation, and examples include polyolefin resins, polyamide resins, polycarbonate resins, polyester resins, polyacetal resins, ABS resins, phenoxy resins, polymethyl methacrylate resins, polyphenylene sulfide resins, polyetherimide resins, polyether ketone resins, etc. Among these, from the aspect of higher adhesion improvement effect of the sizing agent of the present invention, thermosetting resins are preferred, and epoxy resins and vinyl ester resins are further preferred.

[0148] For the purpose of further improving the adhesiveness with the fiber roving, etc., these matrix resins may also be matrix resins in which a part or all of them are modified.

[0149] The manufacturing method of the fiber reinforced composite material is not particularly limited, and known methods such as plastic injection molding using short fibers, long fiber pellets, etc., compression molding using UD sheets, fabric sheets, etc., and other filament winding molding can be adopted.

[0150] The content of the synthetic fiber filament in the fiber-reinforced composite material is not particularly limited and can be appropriately selected according to the type and form of the fiber, the type of the thermoplastic matrix resin, etc., but it is preferably 5 to 70% by weight, more preferably 20 to 60% by weight, based on the obtained fiber-reinforced composite material.

[0151] (Example)

[0152] The present invention will be specifically described below by way of examples, but the present invention is not limited to the described examples. In addition, %, parts shown in the following examples represent "wt%" and "parts by weight" unless otherwise specified. The measurement of each characteristic value is carried out according to the method shown below.

[0153] <Adhesion rate of sizing agent>

[0154] Weigh about 2 g of the sizing agent-coated carbon fiber bundle (W1) (read to the fourth decimal place), and then place it in an electric furnace (capacity 120 cm 3 ) set at a temperature of 450 °C in a nitrogen gas stream of 50 ml / min for 30 minutes to completely thermally decompose the sizing agent. Then transfer it to a container in a dry nitrogen gas stream of 20 l / min, cool for 15 minutes, and weigh the carbon fiber bundle (W2) (read to the fourth decimal place). The sizing agent adhesion amount is calculated by the following formula. In this example, the measurement is carried out 2 times, and the average value is taken as the adhesion rate of the sizing agent.

[0155] Sizing agent adhesion amount (wt%) = [W1 (g) - W2 (g)] / [W1 (g)] × 100

[0156] <Method for producing droplets of matrix resin>

[0157] Epoxy resin: Droplets of a matrix resin adjusted to 100 parts by weight of epoxy resin jER828 (manufactured by Mitsubishi Chemical Corporation) and 3 parts by weight of DICY (manufactured by Mitsubishi Chemical Corporation) are formed on the carbon fiber filaments and cured by heating at 80 °C for 1 hour and 150 °C for 3 hours.

[0158] Polyamide resin: The polyamide resin T-663 (manufactured by Toyobo Co., Ltd.) is melted on a composite material interface property evaluation device HM410 (manufactured by Toei Sangyo Co., Ltd.), and droplets are formed on the carbon fiber filaments

[0159] <Production of non-volatile component sample of fiber sizing agent>

[0160] Lay 2.0 to 3.0 g of the fiber sizing agent flat on an aluminum sheet and dry it at 110 °C under infrared lamp irradiation. The remaining part on the aluminum sheet when the variation range of the volatile component in 150 seconds becomes 0.15% is used as the non-volatile component of the fiber sizing agent.

[0161] <Adhesiveness>

[0162] The adhesion was evaluated by the droplet method using the composite material interface property evaluation device HM410 (manufactured by Toei Sangyo Co., Ltd.).

[0163] Carbon fiber filaments were taken out from the carbon fiber tows obtained in the examples and comparative examples and mounted on a specimen holder. Droplets of each matrix resin were formed on the carbon fiber filaments to obtain test specimens for measurement. The test specimens for measurement were mounted on the device, the droplets were picked up by the device scraper, and the carbon fiber filaments were moved on the device at a speed of 0.06 mm / minute, and the maximum pulling-out load F when pulling out the droplets from the carbon fiber filaments was measured.

[0164] The interfacial shear strength τ was calculated by the following formula to evaluate the adhesion between the carbon fiber filaments and the matrix resin. As the matrix resin, the above-mentioned epoxy resin and polyamide resin were used. The production of each matrix resin droplet was carried out by the method shown above.

[0165] Interfacial shear strength τ (unit: MPa) = F / πdl

[0166] (F: maximum pulling-out load, d: diameter of carbon fiber filament, l: particle size in the pulling-out direction of the droplet)

[0167] Based on the evaluation results, the judgment was made according to the following criteria, and ◎ and 〇 were considered qualified.

[0168] ◎: The interfacial shear strength exceeds 60 Mpa

[0169] 〇: The interfacial shear strength is more than 50 MPa and 60 MPa or less

[0170] ×: The interfacial shear strength is 50 MPa or less

[0171] <Abrasion resistance>

[0172] Using the TM type friction entanglement force testing machine TM-200 (manufactured by Dae Young Scientific Instruments Co., Ltd.), the carbon fiber tows obtained in the examples and comparative examples were rubbed 1000 times (round-trip movement speed: 300 times / minute) with a tension of 50 g through 3 mirror chromium-plated stainless steel needles arranged in a zigzag pattern, and the fuzzing state of the carbon fiber tows was visually judged according to the following criteria, and ◎ and 〇 were considered qualified.

[0173] ◎: The same as before rubbing, and no fuzzing was observed at all.

[0174] 〇: A few fuzzes were observed, but it was a level that was completely okay in practice.

[0175] △: A lot of fuzzing was observed, and several broken wires were confirmed.

[0176] ×: A very large amount of fuzzing and single yarn breakage were confirmed.

[0177] <Bundle property>

[0178] For each sizing agent for sizing carbon fiber (diluted with water to 3%, target adhesion rate 1%), when 10 pieces are cut with a craft knife to a length of 5 mm, visually observe whether they are scattered. It is used for the following evaluation criteria judgment, and ◎ and ○ are qualified.

[0179] ◎: Scattered in 2 pieces or less

[0180] ○: Scattered in 3 - 4 pieces

[0181] △: Scattered in 5 - 7 pieces

[0182] ×: Scattered in 8 pieces or more

[0183] The compounds used in the examples are as follows.

[0184] a1 - 1: jER828 (epoxy resin manufactured by Mitsubishi Chemical Corporation) / Epotohto YD - 011 (epoxy resin manufactured by NIPPON STEEL Chemical & Material Co., Ltd.) = 50 / 50 (weight ratio)

[0185] a1 - 2: Vinyl ester resin (bisphenol A diglycidyl ether acrylic adduct)

[0186] a1 - 3: Unsaturated polyester resin (synthesis example a1 - 3 below)

[0187] a1 - 4: jER807 / jER4005P = 50 / 50 (weight ratio) (epoxy resin mixture manufactured by Mitsubishi Chemical Corporation)

[0188] a1 - 5: Vinyl ester resin (trimethylolpropane trimethacrylate)

[0189] a1 - 6: Unsaturated polyester resin (synthesis example a1 - 6 below)

[0190] a2 - 1: Aromatic polyurethane resin (synthesis example a2 - 1 below)

[0191] a2 - 2: Saturated polyester resin (synthesis example a2 - 2 below)

[0192] a2 - 3: Polyolefin resin (maleic anhydride - modified polypropylene resin (propylene / maleic anhydride graft copolymerization ratio (weight%): 95 / 5, weight - average molecular weight: 30000))

[0193] a2 - 4: Aromatic polyurethane resin (synthesis example a2 - 4 below)

[0194] a2 - 5: Saturated polyester resin (synthesis example a2 - 5 below)

[0195] a2-6: Polyolefin resin (Maleic anhydride modified polypropylene resin (Propylene / maleic anhydride graft copolymerization ratio (weight%): 85 / 15, weight average molecular weight: 37000))

[0196] a3-1: KM-9749 (Silicone emulsion manufactured by Shin-Etsu Chemical Co., Ltd.)

[0197] a3-2: SBL0533 (Latex manufactured by ENEOS Materials Co., Ltd.)

[0198] a3-3: KM-2002-L-1 (Silicone emulsion manufactured by Shin-Etsu Chemical Co., Ltd.)

[0199] a3-4: SBL0548 (Latex manufactured by ENEOS Materials Co., Ltd.)

[0200] a’4: Isooctyl stearate

[0201] b1: The compound in which R in formula (1) 1 is octyl and X and Y are hydrogen atoms

[0202] b2: The compound in which R in formula (1) 1 is methyl and X and Y are hydrogen atoms

[0203] b3: The compound in which R in formula (2) 1 is hydrogen atom

[0204] b4: 2-Amino-1,3,4-thiadiazole

[0205] b5: Reaction product of b1 and cysteine (molar ratio 1:1)

[0206] b’1: 1,4-Thiazine

[0207] b’2: Indole

[0208] c1: POEO block polyether (PO / EO = 20 / 80) (Mw 15500)

[0209] c2: POEO block polyether (PO / EO = 50 / 50) (Mw 4500)

[0210] d1: Diethylene glycol

[0211] d2: Propylene glycol

[0212] d3: 1-Methyl-2-pyrrolidone

[0213] In addition, a1-1, a1-2, a1-3, a1-4, a1-5, a1-6, a2-3, a2-6, a’4 are non-self-emulsifying components.

[0214] (Synthesis Example a1-3)

[0215] React 0.9 mol of maleic anhydride and 1.0 mol of the ethylene oxide 4-molar adduct of bisphenol A at 140 °C for 5 hours to obtain an unsaturated polyester resin (a1-3) with an acid value of 2.5. The weight-average molecular weight (Mw) is 5051, and the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) (Mw / Mn) is 1.6.

[0216] (Synthesis Example a1-6)

[0217] React 0.8 mol of maleic anhydride and 1.0 mol of the ethylene oxide 2-molar adduct of bisphenol A at 140 °C for 3 hours to obtain an unsaturated polyester (a1-6) with an acid value of 3.5. The weight-average molecular weight (Mw) is 1626, and the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) (Mw / Mn) is 1.7.

[0218] (Synthesis Example a2-1)

[0219] Under the condition of sealing nitrogen in the reactor, add 498 parts of terephthalic acid, 332 parts of isophthalic acid, 248 parts of ethylene glycol, 106 parts of diethylene glycol, 45 parts of tetramethylene glycol, and 0.2 part of dibutyltin oxide, and carry out an esterification reaction at 190 - 240 °C for 10 hours to obtain an aromatic polyester polyol. Then, dehydrate 1000 parts of the obtained aromatic polyester polyol under reduced pressure at 120 °C. After cooling to 80 °C, add 680 parts of methyl ethyl ketone and stir to dissolve. Then add 218 parts of isophorone diisocyanate and 67 parts of 2,2-dimethylolpropionic acid as a chain extender, and carry out an ethyl formate reaction at 70 °C for 12 hours. After the reaction is completed, cool to 40 °C, add 97 parts of 13.6% ammonia water to neutralize the reaction, and then carry out a reduced-pressure treatment at 65 °C to distill off methyl ethyl ketone to obtain an aromatic polyurethane resin (a2-1).

[0220] (Synthesis Example a2-4)

[0221] Under the condition of sealing nitrogen in the reactor, 332 parts of terephthalic acid, 332 parts of isophthalic acid, 146 parts of adipic acid, 258 parts of ethylene glycol, 106 parts of diethylene glycol, 52 parts of neopentyl glycol and 0.2 part of dibutyltin oxide were added, and an esterification reaction was carried out at 190 - 240 °C for 10 hours to obtain an aromatic polyester polyol. Then, 1000 parts of the obtained aromatic polyester polyol was dehydrated under reduced pressure at 120 °C, cooled to 80 °C, and 680 parts of methyl ethyl ketone was added and stirred to dissolve. Then, 160 parts of hexamethylene diisocyanate and 67 parts of 2,2 - dimethylolpropionic acid as a chain extender were added, and an ethyl formate reaction was carried out at 70 °C for 12 hours. After the reaction was completed, it was cooled to 40 °C, 97 parts of 13.6% ammonia water was added and a neutralization reaction was carried out, and then it was treated under reduced pressure at 65 °C to distill off methyl ethyl ketone to obtain an aromatic polyurethane resin (a2 - 4).

[0222] (Synthesis Example a2 - 2)

[0223] Under the condition of sealing nitrogen in the reactor, 950 parts of dimethyl isophthalate, 1000 parts of diethylene glycol, 0.5 part of zinc acetate and 0.5 part of antimony trioxide were added, and a transesterification reaction was carried out at 140 - 220 °C for 3 hours. Then, 30 parts of sodium 5 - sulfoisophthalate was added, an esterification reaction was carried out at 220 - 260 °C for 1 hour, and then a polycondensation reaction was carried out at 240 - 270 °C under reduced pressure for 2 hours to obtain a saturated polyester resin (a2 - 2).

[0224] (Synthesis Example a2 - 5)

[0225] Under the condition of sealing nitrogen in the 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 were added, and a transesterification reaction was carried out at 140 - 220 °C for 3 hours. Then, 30 parts of sodium 5 - sulfoisophthalate was added, an esterification reaction was carried out at 220 - 260 °C for 1 hour, and then a polycondensation reaction was carried out at 240 - 270 °C under reduced pressure for 2 hours, and then a polycondensation reaction was carried out at 240 - 270 °C under reduced pressure for 2 hours to obtain a saturated polyester resin (a2 - 5).

[0226] (Manufacture of Sizing Agent for Fibers)

[0227] (Production Example 1)

[0228] 80 parts by weight of an epoxy resin mixture a1 - 1 as a non - self - emulsifying component, 10 parts by weight of c1 as an emulsifier and 10 parts by weight of c2 were added to an emulsifying device, and water was slowly added with stirring for phase - inversion emulsification to obtain a water dispersion of a uniform non - self - emulsifying component (non - volatile component concentration 40% by weight).

[0229] (Production Examples 2 - 6, 9, 12, 17)

[0230] The components selected from a1-2, a1-3, a1-4, a1-5, a1-6, a2-3, a2-6 and a'4 of the non-self-emulsifying component and the components selected from c1 and c2 of the emulsifier are made to have the non-volatile component compositions described in Table 1 respectively. Except for this, an aqueous dispersion of the uniform non-self-emulsifying component (non-volatile component concentration: 40% by weight) is obtained in the same manner as in Example 1. In addition, the values described in the table represent the weight ratios of the respective components in the non-volatile components of the aqueous dispersion.

[0231] (Production Examples 7, 8, 10, 11, 13 to 16)

[0232] Water is added to the components selected from a2-1, a2-2, a2-4, a2-5 and a3-1 to a3-4 of the self-emulsifying component or the aqueous dispersion to obtain an aqueous dispersion having the non-volatile component composition described in Table 1 (non-volatile component concentration: 40% by weight).

[0233] (Production Example 18)

[0234] 50 parts by weight of the aqueous dispersion obtained in Production Example 1 and 50 parts by weight of the aqueous dispersion obtained in Production Example 8 are mixed to obtain an aqueous dispersion (non-volatile component concentration: 40% by weight).

[0235] (Production Examples 19 to 24)

[0236] In Production Example 18, the aqueous dispersions obtained in Production Examples 1 and 8 are made to have the non-volatile component compositions described in Table 2 respectively. Except for this, an aqueous dispersion (non-volatile component concentration: 40% by weight) is obtained in the same manner.

[0237] (Example 1)

[0238] In such a manner that the weight ratio of b1 in the non-volatile components of the sizing agent is 150 ppm, the weight ratio of b3 is 300 ppm, and the weight ratios of d1 and d2 relative to 10,000 parts by weight of the non-volatile components of the sizing agent are 1000 ppm and 100 ppm respectively, b1, b3, d1 and d2 are added to the aqueous dispersion obtained in Production Example 1 to obtain the sizing agent of Example 1.

[0239] (Examples 2 to 53 and Comparative Examples 1 to 8)

[0240] The weight ratios of b1 to b5, b'1 and b'2 in the non-volatile components of the sizing agent, the weight ratios of d1 to d3 relative to 10,000 parts by weight of the non-volatile components of the sizing agent, and the aqueous dispersions used are as described in Tables 3 to 5. Except for this, the sizing agents of Examples 2 to 53 and Comparative Examples 1 to 8 are obtained in the same manner as in Example 1.

[0241] (Manufacture of sized carbon fiber tows)

[0242] The obtained sizing agent was diluted with water to prepare a sizing agent dilution having a nonvolatile component concentration of 2% by weight.

[0243] Subsequently, carbon fiber tows (fineness: 800 tex, number of filaments: 3000) without sizing agent treatment were impregnated and infiltrated with the prepared sizing agent dilution by the Dip Nip method, and then dried in hot air at 105°C for 15 minutes to obtain sized carbon fiber tows. The obtained sized carbon fiber tows were used to evaluate the adhesion rate, adhesiveness, abrasion resistance, and bundling property of the sizing agent by the above method.

[0244] [Table 1]

[0245]

[0246] [Table 2]

[0247]

[0248] [Table 3]

[0249]

[0250] [Table 4]

[0251]

[0252] [Table 5]

[0253]

[0254] As can be seen from Tables 3 and 4, the sizing agents of the examples contain compound (A) and compound (B), and thus can impart excellent adhesiveness to the matrix resin to the fibers, and are suitable for use as sizing agents.

[0255] On the other hand, as shown in Table 5, the sizing agents of the comparative examples are cases where compound (B) is not contained (Comparative Examples 1 to 7) and cases where compound (A) is not contained (Comparative Example 8). From the evaluation results, the adhesiveness to the matrix resin in Comparative Examples 1 to 8 is insufficient, and the problems of the present application cannot be solved.

Claims

1. A sizing agent for fibers, which contains compound A and compound B having a 5-membered ring structure containing a sulfur atom and a nitrogen atom, and the compound A is at least one selected from a thermosetting resin A1, a thermoplastic resin A2, and a rubber A3.

2. The sizing agent for fibers according to claim 1, wherein, The compound B contains at least one selected from the compounds represented by the following general formula (1) and the compounds represented by the following general formula (2). In formula (1), R 1 is an alkyl group, aralkyl group or hydrogen atom having 1 to 12 carbon atoms, and X and Y are independently a hydrogen atom or a halogen atom, In formula (2), R 2 is an alkyl group having 1 to 8 carbon atoms or a hydrogen atom.

3. The sizing agent for fibers according to claim 1 or 2, wherein, The weight ratio of the compound B in the non-volatile components of the sizing agent for fibers is 5 ppm to 10,000 ppm.

4. The sizing agent for fibers according to any one of claims 1 to 3, wherein, The thermosetting resin A1 is at least one selected from an epoxy resin, a vinyl ester resin, an unsaturated polyester resin, and a phenolic resin. The thermoplastic resin A2 is at least one selected from a polyurethane resin, a saturated polyester resin, a polyolefin resin, a polyamide resin, a polyetheretherketone resin, a fluororesin, a phenoxy resin, a polybismaleimide resin, a polyimide resin, a polyethersulfone resin, and a polyetherester resin. The rubber A3 is at least one selected from a silicone rubber and a diene rubber.

5. The sizing agent for fibers according to any one of claims 1 to 4, which further contains a surfactant C.

6. The sizing agent for fibers according to claim 5, wherein, The weight ratio of the surfactant C in the non-volatile components of the sizing agent for fibers is 1 wt% to 50 wt%.

7. The sizing agent for fibers according to any one of claims 1 to 6, wherein, The weight ratio of the compound A in the non-volatile components of the sizing agent for fibers is 20 wt% to 99 wt%.

8. A method for manufacturing a fiber with a sizing agent attached thereto, which includes a step of attaching the sizing agent for fibers according to any one of claims 1 to 7 to the fibers.

9. A fiber roving with a sizing agent attached thereto, to which the sizing agent for fibers according to any one of claims 1 to 7 is attached.

10. A fiber-reinforced composite material, which contains a matrix resin and the fiber roving with a sizing agent attached thereto according to claim 9.

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