Water-based epoxy resin composition, fiber bundling agent, fiber bundle, molding material, and molded article

Abstract

Provided is an aqueous epoxy resin composition, which is characterized by containing an epoxy resin (A), a polyester resin (B) having a sulfonate group, an aromatic nonionic surfactant (C), and an aqueous medium, wherein the content of the above epoxy resin (A) is 75 to 95% by mass in the total solid content. This aqueous epoxy resin composition can be used to manufacture a fiber bundle capable of imparting excellent strength to a molded article, and has excellent long-term storage stability and compounding stability, and thus is suitable for use as a fiber bundling agent.

Description

Technical Field

[0001] The present invention relates to an aqueous epoxy resin composition, a fiber bundling agent, a fiber bundle, a molding material, and a molded article. Background Art

[0002] For automotive components, aircraft components, etc. that require high strength and excellent durability, for example, fiber-reinforced plastics containing matrix resins such as epoxy resins and vinyl ester resins, and fibers such as glass fibers and carbon fibers are used.

[0003] As the glass fibers and carbon fibers used in the above fiber-reinforced plastics, from the viewpoint of imparting high strength, fiber materials that are bundled into approximately several thousand to several tens of thousands by a fiber bundling agent are mostly used.

[0004] As the above fiber bundling agent, a fiber bundling agent is known, which is characterized by containing an epoxy resin, a urethane resin having an alkoxy polyoxyalkylene structure and an epoxy group, a polyester resin having a sulfonate group, and an aqueous medium (for example, refer to Patent Document 1).

[0005] However, this fiber bundling agent sometimes has insufficient adhesiveness to the matrix resin, and sometimes the mechanical strength of the obtained molded article is poor. In addition, for the fiber bundling agent, compatibility stability when a silane coupling agent is blended is required, and thus a material having excellent compatibility stability, long-term storage stability, and adhesiveness to the matrix resin is required.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-160567 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] The problem to be solved by the present invention is to provide an aqueous resin composition that can be used to manufacture a fiber bundle capable of imparting excellent strength to a molded article, and has excellent long-term storage stability and compatibility stability.

[0011] Means for Solving the Problems

[0012] The present inventors conducted research to solve the above problems, and as a result, found that an aqueous epoxy resin composition containing an epoxy resin, a polyester resin having a sulfonate group, an aromatic nonionic surfactant, and an aqueous medium can solve the above problems, and thus completed the present invention.

[0013] That is, the present invention relates to an aqueous epoxy resin composition, which is characterized by containing an epoxy resin (A), a polyester resin (B) having a sulfonate group, an aromatic nonionic surfactant (C), and an aqueous medium, and the content of the above epoxy resin (A) is 75 to 95% by mass in the total solid content.

[0014] Advantages of the Invention

[0015] The aqueous epoxy resin composition of the present invention can be used to manufacture a fiber bundle capable of imparting excellent strength to a molded article, and has excellent long-term storage stability and compounding stability, and thus can be suitably used as a sizing agent for glass fibers and carbon fibers. Detailed Embodiments

[0016] The aqueous epoxy resin composition of the present invention contains an epoxy resin (A), a polyester resin (B) having a sulfonate group, an aromatic nonionic surfactant (C), and an aqueous medium, and the content of the above epoxy resin (A) is 75 to 95% by mass in the total solid content.

[0017] The above epoxy resin (A) will be described. As the above epoxy resin (A), for example, cresol novolac type epoxy resins such as o-cresol novolac type epoxy resin can be mentioned; phenol novolac type epoxy resins such as phenol novolac type epoxy resin, ethylphenol novolac type epoxy resin, butylphenol novolac type epoxy resin, octylphenol novolac type epoxy resin; bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, bisphenol AD novolac type epoxy resin, bisphenol S novolac type epoxy resin, etc. Among these, from the aspect of further improving the heat resistance and mechanical strength of the obtained molded article, cresol novolac type epoxy resin, phenol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol A novolac type epoxy resin, and dicyclopentadiene type epoxy resin are preferred. These epoxy resins (A) can be used alone or in combination of two or more.

[0018] In addition, from the aspect of further improving the strength of the obtained molded article, the epoxy equivalent of the above epoxy resin (A) is preferably in the range of 100 to 3000 g / equivalent, more preferably in the range of 100 to 1000 g / equivalent.

[0019] As the above polyester resin (B) having a sulfonate group, for example, an aromatic polyester resin, an aliphatic polyester resin, etc. can be used. From the aspect of further improving the adhesion strength to the matrix resin and the storage stability, an aromatic polyester resin is preferably used.

[0020] Since the above-mentioned polyester resin (B) has a sulfonate group, it can also function as a dispersant in water.

[0021] From the aspect of further improving the long-term storage stability, the sulfonate group possessed by the above-mentioned polyester resin (B) preferably exists in the above-mentioned polyester resin (C) in the range of 0.1 to 1.0 mol / kg, more preferably in the range of 0.2 to 0.6 mol / kg.

[0022] As the above-mentioned polyester resin (B), from the aspect of further improving the mechanical strength and storage stability of the obtained molded article, a polyester resin having a weight-average molecular weight of 5,000 to 30,000 is preferred, and more preferably in the range of 5,000 to 15,000.

[0023] As the above-mentioned polyester resin (B), from the aspect of further improving the mechanical strength of the obtained molded article, a polyester resin having a glass transition temperature of -20 to 80 °C is preferably used.

[0024] As the above-mentioned polyester resin (B), a polyester resin obtained by reacting a polyol (b1) with a polycarboxylic acid (b2) can be used.

[0025] In addition, the sulfonate group possessed by the above-mentioned polyester resin (B) can be introduced into the above-mentioned polyester resin (B) by using a sulfonate-containing compound such as a polyol having a sulfonate group or a polycarboxylic acid having a sulfonate group in a part of the above-mentioned polyol (b1) and the above-mentioned polycarboxylic acid (b2).

[0026] As the above-mentioned polyol (b1), for example, aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butylpropanediol, diethylene glycol, triethylene glycol, dipropylene glycol, etc.; diols having an aliphatic cyclic structure such as 1,4-cyclohexanedimethanol; polyols having 3 or more hydroxyl groups such as glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, etc. can be used.

[0027] In addition, as the above-mentioned polyol (b1), a polyol having a sulfonate group as a sulfonate-containing compound can also be used in a part or all of it. For example, a polyol having a sulfonate group obtained by sulfonating a polyol having an unsaturated group such as 2-butene-1,4-diol can be used.

[0028] As the above-mentioned polycarboxylic acid (b2), for example, aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, etc.; saturated or unsaturated aliphatic polycarboxylic acids such as oxalic acid, succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, hydrogenated dimer acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, dimer acid, etc.; polycarboxylic acids having an aliphatic cyclic structure such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornenedicarboxylic acid and its anhydride, tetrahydrophthalic acid and its anhydride, etc. Among these, from the aspect of further improving the storage stability, aromatic polycarboxylic acids are preferably used, and terephthalic acid and isophthalic acid are more preferably used.

[0029] In addition, as the above-mentioned polycarboxylic acid (b2), in addition to the above-mentioned polycarboxylic acids, polycarboxylic acids having 3 or more carboxyl groups such as trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, trimellitic acid, ethylene glycol bis(anhydrotrimellitate), glycerol tris(anhydrotrimellitate), 1,2,3,4-butane tetracarboxylic acid, etc. can also be used.

[0030] As the above-mentioned polycarboxylic acid (b2), polycarboxylic acids having a sulfonate group can be used in part or all of it. For example, metal salts such as 4-sulfoisophthalic acid, 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfo-2,7-naphthalenedicarboxylic acid, etc. can be cited. Among these, from the aspect of further improving the storage stability, esterified products of sodium 5-sulfoisophthalate such as sodium 5-sulfoisophthalate and dimethyl sodium 5-sulfoisophthalate are preferably used, and dimethyl sodium 5-sulfoisophthalate is more preferably used.

[0031] The above-mentioned polyester resin (B) can be produced by subjecting the above-mentioned polyol (b1) and the above-mentioned polycarboxylic acid (b2) to an esterification reaction in the absence of a solvent or in an organic solvent by a conventionally known method.

[0032] Specifically, the above-mentioned esterification reaction can be carried out by the following method: in an inert gas atmosphere, with or without a catalyst, heating the above-mentioned polyol (b1) and the above-mentioned polycarboxylic acid (b2) to 180 to 300 °C to carry out an esterification or transesterification reaction, and then carrying out polycondensation under reduced pressure.

[0033] In addition, from the aspect of further improving the storage stability, the compound having a sulfonate group used in the production of the above-mentioned polyester resin (B) is preferably used in the range of 3 to 30% by mass of the total of the above-mentioned polyol (b1) and the above-mentioned polycarboxylic acid (b2).

[0034] As the above-mentioned aromatic nonionic surfactant (C), for example, polyoxyalkylene alkyl phenyl ethers such as polyoxyethylene nonyl phenyl ether can be cited; polyoxyethylene styrenated phenyl ethers such as polyoxyethylene monostyrenated phenyl ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tristyrenated phenyl ether; polyoxyalkylene styrenated phenyl ethers such as polyoxyethylene polyoxypropylene tristyrenated phenyl ether; polyoxyalkylene benzyl phenyl ethers such as polyoxyethylene benzyl phenyl ether; polyoxyalkylene cumyl phenyl ethers such as polyoxyethylene cumyl phenyl ether; polyoxyalkylene naphthyl phenyl ethers such as polyoxyethylene naphthyl phenyl ether; polyoxyalkylene styrenated (alkyl phenyl ether) such as polyoxyethylene styrenated (methyl phenyl ether), etc. Among these, from the aspect of further improving the storage stability and the compatibility stability with the silane coupling agent, polyoxyethylene styrenated phenyl ether having 40 or more oxyethylene units is preferred, and polyoxyethylene styrenated phenyl ether having 40 or more oxyethylene units is more preferred. These aromatic nonionic surfactants (C) can be used alone or in combination of two or more.

[0035] In addition, other surfactants other than the above-mentioned aromatic nonionic surfactant (C) can be used in combination in the aqueous epoxy resin composition of the present invention. From the aspect of further improving the storage stability and the compatibility stability with the silane coupling agent, the other surfactants in the surfactant are preferably less than 10%.

[0036] As the above-mentioned aqueous medium, water, an organic solvent miscible with water, and a mixture thereof can be cited. As the organic solvent miscible with water, for example, alcohol compounds such as methanol, ethanol, n-propanol, and isopropanol can be cited; ketone compounds such as acetone and methyl ethyl ketone; polyalkylene glycol compounds such as ethylene glycol, diethylene glycol, and propylene glycol; alkyl ether compounds of polyalkylene glycol; lactam compounds such as N-methyl-2-pyrrolidone, etc. In the present invention, only water can be used. In addition, a mixture of water and an organic solvent miscible with water can also be used, and only an organic solvent miscible with water can also be used. From the aspects of safety and environmental load, only water or a mixture of water and an organic solvent miscible with water is preferred, and only water is particularly preferred.

[0037] The aqueous epoxy resin composition of the present invention can be obtained, for example, by the following method: mixing and stirring the above-mentioned epoxy resin (A), the above-mentioned polyester resin (B), the aromatic nonionic surfactant (C), and the solvent, and then mixing their mixture with the aqueous medium and removing the solvent as needed.

[0038] In the solid content of the aqueous epoxy resin composition of the present invention, the above-mentioned epoxy resin (A) is 75 to 95% by mass, and from the aspect of further improving the interlaminar shear strength of the obtained molded product, it is preferably 80 to 95% by mass.

[0039] From the aspect of further improving the dispersion stability and the compounding stability, the above polyester resin (B) in the solid content of the aqueous epoxy resin composition of the present invention is preferably 0.5 to 10% by mass, more preferably 0.5 to 5% by mass.

[0040] From the aspect of further improving the compounding stability and the mechanical strength of the molded article, the above aromatic nonionic surfactant (C) in the solid content of the aqueous epoxy resin composition of the present invention is preferably 1 to 25% by mass, more preferably 2 to 20% by mass.

[0041] In addition, from the aspect of further improving the compounding stability and the durability of the molded article, the mass ratio (B / C) of the above polyester resin (B) to the above aromatic nonionic surfactant (C) in the solid content of the fiber bundling agent of the present invention is preferably 0.1 to 0.75.

[0042] From the viewpoints of storage stability and economy, the solid content in the aqueous epoxy resin composition of the present invention is preferably 40 to 70% by mass, more preferably 45 to 65% by mass.

[0043] From the viewpoints of storage stability and economy, the above aqueous medium in the aqueous epoxy resin composition of the present invention is preferably 30 to 60% by mass, more preferably 35 to 55% by mass.

[0044] From the aspect of facilitating operations such as taking out from the container during use, the viscosity of the aqueous epoxy resin composition of the present invention is preferably 1000 mPa·s or less, more preferably 500 mPa·s or less. It should be noted that the viscosity is the value measured at 25°C of the aqueous epoxy resin composition using a rotational viscometer.

[0045] From the aspect of reducing the sedimentation rate of particles during storage, maintaining long-term uniformity, and making the attachment of particles to fibers uniform, the volume average particle diameter of the aqueous epoxy resin composition of the present invention is preferably 0.1 to 1.0 μm, more preferably 0.1 to 0.5 μm. It should be noted that the volume average particle diameter is the value measured using a laser diffraction particle size distribution analyzer.

[0046] In addition, the aqueous epoxy resin composition of the present invention may, as needed, be used in combination with additives such as silane coupling agents, curing catalysts, lubricants, fillers, thixotropy imparting agents, tackifiers, waxes, heat stabilizers, light stabilizers, fluorescent brighteners, foaming agents, pH regulators, leveling agents, anti-gelation agents, dispersion stabilizers, antioxidants, radical scavengers, heat resistance imparting agents, inorganic fillers, organic fillers, plasticizers, reinforcing agents, catalysts, antibacterial agents, mildewproofing agents, rust inhibitors, thermoplastic resins, thermosetting resins, pigments, dyes, conductivity imparting agents, antistatic agents, moisture permeability improvers, water repellents, oil repellents, hollow foams, compounds containing crystal water, flame retardants, water absorbents, moisture absorbents, deodorants, foam regulators, defoamers, anti-mildew agents, preservatives, anti-algae agents, pigment dispersants, anti-blocking agents, and hydrolysis inhibitors.

[0047] When the aqueous epoxy resin composition of the present invention is used as a sizing agent for glass fibers, in terms of further improving the adhesion strength of the sizing agent to glass fibers, it is preferable to use a silane coupling agent in combination.

[0048] As the above-mentioned silane coupling agent, for example, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-hydroxyethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, γ-(2-hydroxyethyl)aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, γ-(2-hydroxyethyl)aminopropylmethyldimethoxysilane, γ-(2-hydroxyethyl)aminopropylmethyldiethoxysilane or γ-(N,N-di-2-hydroxyethyl)aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane or γ-(N-phenyl)aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptophenyltrimethoxysilane, etc. can be used.

[0049] The above-mentioned silane coupling agent is preferably used in the range of 1 to 30 parts by mass based on 100 parts by mass of the solid content of the aqueous epoxy resin composition of the present invention.

[0050] In addition, the aqueous epoxy resin composition of the present invention can also be used in combination with emulsions such as vinyl acetate-based, ethylene-vinyl acetate-based, acrylic-based, epoxy-based, urethane-based, polyester-based, polyamide-based, etc.; latexes such as styrene-butadiene-based, acrylonitrile-butadiene-based, acrylic-butadiene-based, etc., and water-soluble resins such as polyvinyl alcohol and cellulose.

[0051] The fiber sizing agent of the present invention contains the aqueous epoxy resin composition of the present invention. For example, for the purpose of preventing filament breakage, fuzzing, etc. of glass fibers, carbon fibers, etc., it can be used for the sizing and surface treatment of multiple fibers.

[0052] Examples of the fiber materials that can be treated with the fiber sizing agent of the present invention include glass fibers, carbon fibers, silicon carbide fibers, pulp, hemp, cotton, nylon, polyester, acrylic, polyurethane, polyimide, or polyamide fibers formed from aromatic polyamides such as Kevlar and Nomex. Among these, glass fibers and carbon fibers are of high strength, so they are preferably used.

[0053] As the glass fibers that can be treated with the above fiber sizing agent, for example, glass fibers obtained using alkali-containing glass, low-alkali glass, alkali-free glass, etc. as raw materials can be used. Particularly preferably, alkali-free glass (E glass) with less deterioration over time and stable mechanical properties is used.

[0054] In addition, as the carbon fibers that can be treated with the above fiber sizing agent, generally, carbon fibers such as polyacrylonitrile-based and pitch-based can be used. Among them, as the above carbon fibers, from the viewpoint of imparting excellent strength, polyacrylonitrile-based carbon fibers are preferably used.

[0055] In addition, as the above carbon fibers, from the viewpoint of imparting further excellent strength, etc., carbon fibers having a monofilament diameter of 0.5 to 20 μm are preferably used, and carbon fibers of 2 to 15 μm are more preferably used.

[0056] As the above carbon fibers, for example, carbon fibers that have been twisted, spun, textile processed, or non-woven processed can be used. In addition, as the above carbon fibers, carbon fibers such as filaments, yarns, rovings, raw yarns, chopped strands, felts, needled fabrics, fabrics, roving fabrics, and abrasive fibers can be used.

[0057] As a method of sizing the above glass fibers and carbon fibers using the fiber sizing agent of the present invention and forming a film on the surface of the above glass fiber bundle and carbon fiber bundle, for example, a method of uniformly coating the fiber sizing agent on the fiber surface by a kiss coating method, a roll method, an impregnation method, a spraying method, a brush, or other known methods can be cited. When the above fiber sizing agent contains an aqueous medium and an organic solvent as a solvent, it is preferably heated and dried using a heating roll, hot air, a hot plate, etc. after the above coating.

[0058] The adhesion amount of the film formed on the surface of the above fiber material is preferably 0.1 to 5% by mass, more preferably 0.3 to 1.5% by mass, based on the total mass of the sized and surface-treated fiber bundle.

[0059] The fiber material that has been bundled and surface-treated by the above method, especially glass fiber and carbon fiber, can be used in a molding material for manufacturing a high-strength molded article by being used in combination with a matrix resin (D) described later, etc.

[0060] In particular, when the fiber material surface-treated with the fiber bundling agent of the present invention is used in combination with the matrix resin (D) to form a molded article or the like, the adhesion of the above fiber to the interface of the matrix resin (D) can be significantly improved, so the strength of the molded article can be improved.

[0061] As the above matrix resin (D), for example, a thermosetting resin (D1) or a thermoplastic resin (D2) can be used. As the above thermosetting resin (D1), a phenolic resin, a polyimide resin, a bismaleimide resin, an unsaturated polyester resin, an epoxy resin, a vinyl ester resin, etc. can be used. As the above thermoplastic resin (D2), for example, saturated polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polypropylene, polystyrene, polycarbonate, polyphenylene sulfide, polyphenylene ether, polyamide resins such as 6-nylon and 6,6-nylon, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, polyacetal, polyetherimide, polyetheretherketone, etc. can be used.

[0062] From the aspect of obtaining a high-strength molded article, the fiber obtained by bundling etc. using the fiber bundling agent of the present invention is more preferably used in combination with a matrix resin such as epoxy resin, unsaturated polyester resin, polyamide resins such as 6-nylon and 6,6-nylon, polyphenylene sulfide, polybutylene terephthalate, polycarbonate, and polyetheretherketone.

[0063] As a molding material containing the above surface-treated fiber material, the above matrix resin (D) and, if necessary, a polymerizable monomer, etc., for example, prepreg, sheet molding compound (SMC), etc. can be cited.

[0064] The above prepreg can be manufactured, for example, by coating the above matrix resin (D) on a release paper, placing the surface-treated fiber material on its coating surface, and pressing and impregnating it with a roller or the like if necessary.

[0065] When manufacturing the above prepreg, as the above matrix resin (D), epoxy resins such as bisphenol A type epoxy resin, glycidylamine type epoxy resins such as tetraglycidylamino diphenylmethane, and linear phenolic type epoxy resins are preferably used.

[0066] In addition, the above-mentioned sheet molding compound can be manufactured, for example, by sufficiently impregnating a mixture of the above-mentioned matrix resin (D1) and a polymerizable unsaturated monomer such as styrene into the above-mentioned surface-treated fiber material and processing it into a sheet shape. When manufacturing the above-mentioned sheet molding compound, as the above-mentioned matrix resin (D1), an unsaturated polyester resin or a vinyl ester resin is preferably used.

[0067] The curing of the above-mentioned molding material is carried out, for example, by radical polymerization under pressure or normal pressure, with heating or light irradiation. In this case, known thermal curing agents, photo-curing agents, etc. can be used in combination.

[0068] In addition, as the above-mentioned molding material, for example, a material obtained by kneading the above-mentioned thermoplastic resin (D2) and the above-mentioned surface-treated fiber material under heating can be cited. This molding material can be used for secondary processing such as by injection molding.

[0069] In addition, a prepreg using the above-mentioned thermoplastic resin (D2) can be manufactured, for example, by placing the surface-treated fiber material in a sheet form and impregnating it with the above-mentioned molten thermoplastic resin (D2).

[0070] The prepreg using the above-mentioned thermoplastic resin (D2) can be used for secondary processing such as by laminating one or more sheets and then heating under pressure or normal pressure for molding.

[0071] The molded product obtained using the above-mentioned molding material has high strength, and thus can be used for, for example, automotive components, aircraft components, industrial components, etc.

[0072] Examples

[0073] Hereinafter, the present invention will be described more specifically by way of examples. It should be noted that the average molecular weight of the resin was measured under the following GPC measurement conditions.

[0074] [GPC Measurement Conditions]

[0075] Measurement device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)

[0076] Columns: The following columns manufactured by Tosoh Corporation were connected in series and used.

[0077] "TSKgel G5000" (7.8 mm I.D. × 30 cm) × 1 piece

[0078] "TSKgel G4000" (7.8 mm I.D. × 30 cm) × 1 piece

[0079] "TSKgel G3000" (7.8 mm I.D. × 30 cm) × 1 piece

[0080] “TSKgel G2000” (7.8 mm I.D. × 30 cm) × 1 column

[0081] Detector: RI (Differential Refractometer)

[0082] Column temperature: 40 °C

[0083] Eluent: Tetrahydrofuran (THF)

[0084] Flow rate: 1.0 mL / min

[0085] Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 4 mg / mL)

[0086] Standard sample: A calibration curve was prepared using the following monodisperse polystyrene.

[0087] (Monodisperse polystyrene)

[0088] “TSKgel Standard Polystyrene A-500” manufactured by Tosoh Corporation

[0089] “TSKgel Standard Polystyrene A-1000” manufactured by Tosoh Corporation

[0090] “TSKgel Standard Polystyrene A-2500” manufactured by Tosoh Corporation

[0091] “TSKgel Standard Polystyrene A-5000” manufactured by Tosoh Corporation

[0092] “TSKgel Standard Polystyrene F-1” manufactured by Tosoh Corporation

[0093] “TSKgel Standard Polystyrene F-2” manufactured by Tosoh Corporation

[0094] “TSKgel Standard Polystyrene F-4” manufactured by Tosoh Corporation

[0095] “TSKgel Standard Polystyrene F-10” manufactured by Tosoh Corporation

[0096] “TSKgel Standard Polystyrene F-20” manufactured by Tosoh Corporation

[0097] “TSKgel Standard Polystyrene F-40” manufactured by Tosoh Corporation

[0098] “TSKgel Standard Polystyrene F-80” manufactured by Tosoh Corporation

[0099] “TSKgel Standard Polystyrene F-128” manufactured by Tosoh Corporation

[0100] “TSKgel Standard Polystyrene F-288” manufactured by Tosoh Corporation

[0101] "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

[0102] (Production Example 1: Production of Polyester Resin (B-1))

[0103] Into a reaction vessel adjusted to 180°C, 558 parts by mass of ethylene glycol, 478 parts by mass of diethylene glycol, 896 parts by mass of terephthalic acid, 478 parts by mass of isophthalic acid, and 0.5 part by mass of butyltin hydroxyoxide were charged, and the temperature was raised to 240°C over 4 hours, and then the reaction was continued at 240°C, and about 260 parts by mass of the distillate was collected. Next, after cooling to 180°C, 213 parts by mass of sodium 5-sulfoisophthalate dimethyl ester and 0.5 part by mass of tetraisopropyl titanate were charged, and the temperature was further raised to 260°C, and a polycondensation reaction was carried out under a reduced pressure of 2.0 mm of mercury column for 1 hour, whereby a polyester resin (B-1) having a weight average molecular weight of 8900 and a glass transition temperature of 44°C was obtained. The sulfonate group concentration of this polyester (B-1) was 0.31 mol / kg, and the carboxyl group concentration was 0.05 mmol / g.

[0104] (Production Example 2: Production of Polyester Resin (RB-1))

[0105] Using 53 parts by mass of trimellitic acid in place of the total amount of sodium 5-sulfoisophthalate dimethyl ester used in Production Example 1, a polycondensation reaction was carried out in the same manner as in Production Example 1, whereby a polyester resin (RB-1) was obtained. The weight average molecular weight of this polyester (RB-1) was 11,000, and the carboxyl group concentration was 0.31 mmol / g.

[0106] (Example 1: Production and Evaluation of Aqueous Epoxy Resin Composition (1))

[0107] In a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 180 parts by mass of cresol novolak type epoxy resin (epoxy equivalent 209 g / equivalent, softening point 75°C; hereinafter simply referred to as "epoxy resin (A-1)"), 4 parts by mass of polyester resin (B-1), 8 parts by mass of polyoxyethylene styrenated phenyl ether (average number of moles of ethylene oxide added: 40; hereinafter simply referred to as "aromatic nonionic surfactant (C-1)"), 8 parts by mass of polyoxyethylene distyrenated phenyl ether (average number of moles of ethylene oxide added: 18; hereinafter simply referred to as "aromatic nonionic surfactant (C-2)"), and 77 parts by mass of methyl ethyl ketone were added, dissolved at 75°C, and then cooled to 40°C. Next, while stirring with a homogenizer, 530 parts by mass of ion-exchanged water was slowly added to obtain an aqueous dispersion. The solvent was removed from this aqueous dispersion by distillation under reduced pressure and concentrated to 60% of the non-volatile components, whereby an aqueous epoxy resin composition (1) was obtained.

[0108] (Example 2: Manufacture and Evaluation of Aqueous Epoxy Resin Composition (2))

[0109] In a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 184 parts by mass of phenol novolac epoxy resin (epoxy equivalent 182 g / equivalent, semi-solid type; hereinafter simply referred to as "epoxy resin (A-2)"), 2 parts by mass of polyester resin (B-1), 10 parts by mass of polyoxyethylene diphenyl ether (average number of moles of ethylene oxide added 60; hereinafter simply referred to as "aromatic nonionic surfactant (C-3)"), 4 parts by mass of polyoxyethylene polyoxypropylene triphenyl ether (average number of moles of ethylene oxide added 21, average number of moles of propylene oxide added 4; hereinafter simply referred to as "aromatic nonionic surfactant (C-4)"), and 79 parts by mass of methyl ethyl ketone were added. After dissolving at 75°C, it was cooled to 40°C. Next, 530 parts by mass of ion-exchanged water was slowly added while stirring with a homogenizer to obtain an aqueous dispersion. The solvent was removed by distillation under reduced pressure from this aqueous dispersion and concentrated to a non-volatile content of 50% by mass, thereby obtaining an aqueous epoxy resin composition (2).

[0110] (Example 3: Manufacture and Evaluation of Aqueous Epoxy Resin Composition (3))

[0111] In a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 188 parts by mass of bisphenol A epoxy resin (epoxy equivalent 475 g / equivalent, softening point 70°C; hereinafter simply referred to as "epoxy resin (A-3)"), 4 parts by mass of polyester resin (B-1), 8 parts by mass of polyoxyethylene triphenyl ether (average number of moles of ethylene oxide added 40; hereinafter simply referred to as "aromatic nonionic surfactant (C-5)"), and 81 parts by mass of methyl ethyl ketone were added. After dissolving at 75°C, it was cooled to 40°C. Next, 520 parts by mass of ion-exchanged water was slowly added while stirring with a homogenizer to obtain an aqueous dispersion. The solvent was removed by distillation under reduced pressure from this aqueous dispersion and concentrated to a non-volatile content of 55% by mass, thereby obtaining an aqueous epoxy resin composition (3).

[0112] (Example 4: Manufacture and Evaluation of Aqueous Epoxy Resin Composition (4))

[0113] In a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 180 parts by mass of bisphenol A linear phenolic epoxy resin (epoxy equivalent 210 g / equivalent, softening point 85°C; hereinafter simply referred to as "epoxy resin (A-4)"), 6 parts by mass of polyester resin (B-1), 8 parts by mass of aromatic nonionic surfactant (C-3), 4 parts by mass of aromatic nonionic surfactant (C-4), 2 parts by mass of polyoxyethylene-polyoxypropylene block polymer (weight-average molecular weight 17,000, oxyethylene component 80 mass%), and 77 parts by mass of methyl ethyl ketone were added. After dissolving at 75°C, it was cooled to 40°C. Next, 511 parts by mass of ion-exchanged water was slowly added while stirring with a homogenizer to obtain an aqueous dispersion. The solvent was removed by distillation under reduced pressure from this aqueous dispersion and concentrated to 50 mass% of the non-volatile components, thereby obtaining an aqueous epoxy resin composition (4).

[0114] (Comparative Example 1: Preparation and Evaluation of Aqueous Epoxy Resin Composition (R1))

[0115] In a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 200 parts by mass of epoxy resin (A-1), 200 parts by mass of polyester resin (B-1), 130 parts by mass of N-methyl-2-pyrrolidone, and 50 parts by mass of methyl ethyl ketone were added. After dissolving at 75°C, it was cooled to 60°C. Next, 1000 parts by mass of ion-exchanged water was slowly added while stirring with a homogenizer to obtain an aqueous dispersion. Methyl ethyl ketone was removed by distillation under reduced pressure from this aqueous dispersion and concentrated to 35 mass% of the non-volatile components, thereby obtaining an aqueous epoxy resin composition (R1).

[0116] (Comparative Example 2: Preparation and Evaluation of Aqueous Epoxy Resin Composition (R2))

[0117] In a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 70 parts by mass of epoxy resin (A-2), 6 parts by mass of polyester (B-1), 60 parts by mass of aromatic nonionic surfactant (C-3), 64 parts by mass of aromatic nonionic surfactant (C-2), and 30 parts by mass of methyl ethyl ketone were added. After dissolving at 75°C, it was cooled to 40°C. Next, 570 parts by mass of ion-exchanged water was slowly added while stirring with a homogenizer to obtain an aqueous dispersion. The solvent was removed by distillation under reduced pressure from this aqueous dispersion and concentrated to 35 mass% of the non-volatile components, thereby obtaining an aqueous epoxy resin composition (R2).

[0118] (Comparative Example 3: Preparation and Evaluation of Aqueous Epoxy Resin Composition (R3))

[0119] In a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 180 parts by mass of epoxy resin (A-2), 4 parts by mass of polyester (RB-1), 8 parts by mass of aromatic nonionic surfactant (C-3), 8 parts by mass of aromatic nonionic surfactant (C-2), and 77 parts by mass of methyl ethyl ketone were added. After dissolving at 75°C, it was cooled to 40°C. Next, 6.2 parts by mass of triethylamine was added, and it was stirred and mixed until homogeneous. Next, 530 parts by mass of ion-exchanged water was slowly added to obtain an aqueous dispersion. The solvent was removed by distillation under reduced pressure from this aqueous dispersion and concentrated to a non-volatile content of 35% by mass, thereby obtaining an aqueous epoxy resin composition (R3).

[0120] (Comparative Example 4: Production and Evaluation of Aqueous Epoxy Resin Composition (R4))

[0121] In a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 180 parts by mass of epoxy resin (A-1), 10 parts by mass of aromatic nonionic surfactant (C-1), 10 parts by mass of aromatic nonionic surfactant (C-2), and 77 parts by mass of methyl ethyl ketone were added. After dissolving at 75°C, it was cooled to 40°C. Next, while stirring with a homogenizer, 530 parts by mass of ion-exchanged water was slowly added to obtain an aqueous dispersion. The solvent was removed by distillation under reduced pressure from this aqueous dispersion and concentrated to a non-volatile content of 40% by mass, thereby obtaining an aqueous epoxy resin composition (R4).

[0122] [Method for Measuring Non-Volatile Content]

[0123] In a metal petri dish (inner diameter 65 mm, depth 14 mm) whose tare weight had been accurately weighed to the fourth decimal place in advance, approximately 1 g of the above-obtained aqueous epoxy resin composition was accurately weighed to the fourth decimal place, and 5 ml of ion-exchanged water was added. The non-volatile content was determined from the remaining amount of the sample after drying at 107°C for 1.5 hours in a hot air circulation dryer. The following shows the calculation formula for the non-volatile content.

[0124] Non-volatile content (mass%) = [(W3 - W1) / (W2 - W1)] × 100

[0125] W1: Mass of the metal petri dish (g)

[0126] W2: Mass of the metal petri dish + Mass of the weighed sample (g)

[0127] W3: Mass of the metal petri dish + Mass of the dried sample (g)

[0128] [Method for Measuring Viscosity]

[0129] For the above-obtained freshly produced aqueous epoxy resin composition, the following measuring equipment was used for measurement.

[0130] Measuring equipment: VISCOMETER MODEL RB100L (manufactured by Toki Sangyo Co., Ltd.), measuring temperature: 25°C, rotor speed: 60 rpm, measuring time: 60 seconds

[0131] [Method for measuring average particle size]

[0132] For the above-mentioned freshly manufactured aqueous epoxy resin composition, ion-exchanged water is used for dilution so that the concentration of the epoxy resin is in the range of several tens to several hundreds of ppm, and the resulting solution is used as the measurement solution. The volume average particle size is measured using the following measuring equipment.

[0133] Measuring equipment: SALD-2300 (manufactured by Shimadzu Corporation), measuring temperature: 23°C

[0134] [Evaluation of storage stability (appearance)]

[0135] The above-mentioned aqueous epoxy resin composition is stored at 40°C for 30 days, and the presence or absence of precipitation and solidification of the liquid is visually confirmed, and the storage stability is evaluated according to the following criteria.

[0136] ○: No change

[0137] △: There are some precipitates

[0138] ×: Severe precipitation or solidification

[0139] [Evaluation of storage stability (residual rate of epoxy group)]

[0140] The above-mentioned aqueous epoxy resin composition is stored at 40°C for 30 days, and the epoxy equivalent before and after storage is measured by the pyridine hydrochloride method, and the residual rate of the epoxy group is calculated.

[0141] "Residual rate of epoxy group (%)" = "Epoxy equivalent before storage (g / equivalent)" / "Epoxy equivalent after storage (g / equivalent)" × 100

[0142] [Evaluation of compatibility stability]

[0143] Ion-exchanged water and γ-aminopropyltriethoxysilane are added to the above-mentioned aqueous epoxy resin composition to prepare a 20% by mass aqueous dilution of the non-volatile component with an epoxy resin / γ-aminopropyltriethoxysilane = 10 / 1 (solid content ratio). Next, it is allowed to stand at 40°C for 3 days, and the presence or absence of agglomerates and solidification of the liquid is visually confirmed, and the compatibility stability is evaluated according to the following criteria.

[0144] ○: No change

[0145] △: There are some precipitates

[0146] ×: Vigorous precipitation or solidification of the precipitate

[0147] [Treatment of carbon fiber sizing agent]

[0148] The unsized filaments of polyacrylonitrile-based carbon fibers (diameter 7 μm / 7000 filaments) were bundled, and the substance obtained by diluting the above-mentioned aqueous epoxy resin composition with ion-exchanged water to a non-volatile component of 5% by mass was impregnated by an impregnation method, and then extruded with a roller, thereby adjusting the adhesion amount of the active ingredient to 1% by mass. Next, heat treatment was performed at 150 °C for 30 minutes to obtain a carbon fiber bundle surface-treated with the aqueous epoxy resin composition.

[0149] [Production of epoxy molded article]

[0150] 4 parts by mass of dicyandiamide and 4 parts by mass of N-(3,4-dichlorophenyl)-N',N'-dimethylurea were blended in 50 parts by mass of bisphenol A liquid epoxy resin (epoxy equivalent 188 g / equivalent), 20 parts by mass of bisphenol A solid epoxy resin (epoxy equivalent 475 g / equivalent, softening point 70 °C), and 30 parts by mass of cresol novolac epoxy resin (epoxy equivalent 209 g / equivalent, softening point 75 °C), and then coated on a release paper. After arranging the above-mentioned carbon fiber bundles in parallel at equal intervals in one direction on the coated resin film, heating was performed to impregnate the epoxy resin, and a prepreg with a carbon fiber content of 60% by volume was produced. The produced prepregs were laminated and treated under pressure at 150 °C for 1 hour, and then treated at 140 °C for 4 hours to obtain a molded article.

[0151] [Evaluation of interlaminar shear strength of epoxy molded article]

[0152] For a test plate with a thickness of 2.5 mm and a width of 6.0 mm of the molded article, the interlaminar shear strength was measured by the method according to ASTM D-2344. In addition, for a test plate obtained by boiling the same test plate in distilled water for 72 hours, the interlaminar shear strength was also measured in the same manner.

[0153] [Production of chopped carbon fiber rovings]

[0154] The unsized filaments of polyacrylonitrile-based carbon fibers (diameter 7 μm / 6000 filaments) were bundled, and the substance obtained by diluting the above-mentioned aqueous epoxy resin composition with ion-exchanged water to a non-volatile component of 5% by mass was impregnated by an impregnation method, and then extruded with a roller, thereby adjusting the adhesion amount of the active ingredient to 1% by mass. Next, the carbon fiber bundle was cut into lengths of about 4 mm, and heat treatment was performed at 150 °C for 30 minutes to obtain chopped carbon fiber rovings surface-treated with a carbon fiber sizing agent.

[0155] [Production of PPS molded article]

[0156] Mix 30 parts by mass of the obtained chopped carbon fiber filaments or 30 parts by mass of the chopped glass fiber filaments uniformly with 70 parts by mass of polyphenylene sulfide (PPS). Next, put the above-mentioned compounded materials into a twin-screw extruder with an outlet, and perform melt-kneading at a set resin temperature of 330 °C to obtain pellets of the resin composition. Using these pellets, perform molding with an injection molding machine to obtain a PPS molded product.

[0157] [Measurement of Tensile Strength of PPS Molded Product]

[0158] According to the measurement method of ISO527, measure the tensile strength of each test piece. The test piece used is a dumbbell-shaped tensile test piece with a total length of 170 mm, a length of the narrow parallel part of 80 mm, a width of the narrow parallel part of 10 mm, a distance between the wide parallel parts of 109 mm, a width of the wide parallel part of 20 mm, and a thickness of 4 mm.

[0159] [Measurement of Damp Heat Resistance of PPS Molded Product]

[0160] After immersing each test piece in an ethylene glycol aqueous solution (50% by mass) at a high temperature of 140 °C for 3000 hours, measure the tensile strength of each test piece according to the measurement method of ISO527.

[0161] Show the compositions and evaluation results of Examples 1 to 4 above in Table 1.

[0162] [Table 1]

[0163]

[0164] Show the compositions and evaluation results of Comparative Examples 1 to 4 above in Table 2.

[0165] [Table 2]

[0166]

[0167] It was confirmed that the storage stability and compounding stability of the aqueous epoxy resin compositions of Examples 1 to 4 as the aqueous epoxy resin composition of the present invention are excellent, and the interlaminar shear strength and tensile strength of the molded products obtained using them are excellent.

[0168] On the other hand, Comparative Example 1 is an example that does not contain the aromatic nonionic surfactant (C) which is an essential component of the present invention, and it was confirmed that the compounding stability is poor and the interlaminar shear strength of the molded product is also insufficient.

[0169] Comparative Example 2 is an example where the content of the epoxy resin (A) is less than the lower limit of the present application invention, and it was confirmed that the interlaminar shear strength and the tensile strength after the damp heat test of the molded product are insufficient.

[0170] Comparative Examples 3 and 4 are examples that do not contain the sulfonic acid group-containing polyester resin (B) which is an essential component of the present invention, and it was confirmed that the storage stability was insufficient.

Claims

1. An aqueous epoxy resin composition, characterized in that, It contains an epoxy resin (A), a polyester resin (B) having a sulfonate group, an aromatic nonionic surfactant (C), and an aqueous medium. The epoxy resin (A) is at least one selected from cresol novolak type epoxy resin, phenol novolak type epoxy resin, bisphenol A type epoxy resin, bisphenol A novolak type epoxy resin, and dicyclopentadiene type epoxy resin. The content of the epoxy resin (A) is 75% to 95% by mass in the total solid content. The content of the polyester resin (B) in the solid content of the aqueous epoxy resin composition is 0.5% to 10% by mass. The aromatic nonionic surfactant (C) contains a surfactant having 40 or more oxyethylene units. The content of the aromatic nonionic surfactant (C) in the solid content of the aqueous epoxy resin composition is 1% to 25% by mass.

2. The aqueous epoxy resin composition according to claim 1, wherein, The sulfonate group concentration of the polyester resin (B) is 0.2 mol / kg to 0.6 mol / kg.

3. A fiber bundling agent, characterized in that, It contains the aqueous epoxy resin composition according to claim 1 or 2.

4. A fiber bundle, characterized in that, It is bundled by the fiber bundling agent according to claim 3.

5. A forming material, characterized in that, It contains the fiber bundle according to claim 4 and a matrix resin.

6. A molded article, characterized in that, It is a cured product of the molding material according to claim 5.

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