Resin composition for tow prepreg and tow prepreg

Abstract

To provide a resin composition for a tow prepreg, that achieves a tow prepreg having excellent impregnability, unwindability, fracture toughness, and heat resistance.SOLUTION: An unsaturated resin composition for a prepreg according to the present invention contains a urethane (meth)acrylate resin (A), a (meth)acrylate monomer (B) having a molecular weight of 200 or more and 500 or less, a thermoplastic polyurethane resin (C), a polytetramethylene ether compound (D) having an acryl group or a methacryl group at a terminal, and a polymerization initiator (E). The (meth)acrylate monomer (B) includes a first (meth)acrylate monomer (b1) with an aromatic skeleton and a second (meth)acrylate monomer (b2) with an alicyclic skeleton, exhibiting a weight loss rate (%) of less than 3 after heating at 50°C for 1 hour under atmospheric pressure. The molecular weight of the polyether segment of the polytetramethylene ether compound (D) is 1000 or more and 3000 or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resin composition for a tow prepreg and a tow prepreg. [Background technology]

[0002] Fiber-reinforced resin composite materials, in which reinforcing fibers such as carbon fibers and glass fibers are impregnated with resin, are lightweight yet excellent in heat resistance and mechanical strength, and are therefore used in a variety of applications, such as automobile parts, aerospace parts, housing equipment parts, and sports parts. Conventionally, as a molding method for fiber-reinforced resin composite materials, a method has been known in which an intermediate material called a prepreg, in which reinforcing fibers are impregnated with a thermosetting resin, is cured and molded by autoclave molding, press molding, filament winding molding, pultrusion molding, or the like. For example, Patent Document 1 discloses that a molded body having excellent flexibility, impact resistance, and heat resistance can be produced by preparing a resin composition for prepreg containing a urethane (meth)acrylate, a polymerization initiator, and a thermoplastic polyurethane resin, and press-molding the prepreg in which the resin composition for prepreg is impregnated into reinforcing fibers.

[0003] On the other hand, high-pressure tanks for storing natural gas, hydrogen gas, etc., are required to have even better durability and impact resistance. For example, Patent Document 2 discloses a manufacturing method for the high-pressure tank, which uses a tow prepreg in which a bundle of reinforced fibers (tows) such as carbon fibers and glass fibers is impregnated with a resin. According to Patent Document 2, it is said that a lightweight and high-strength high-pressure tank can be manufactured.

[0004] In view of this, a tow prepreg in which the resin composition for prepregs disclosed in Patent Document 1 is impregnated into a tow may be considered as a molding material for producing a high-pressure tank.

[0005] However, in this case, since the viscosity of the resin composition for prepreg disclosed in Patent Document 1 is high, there is a disadvantage that the impregnation into the tow is low and the unwinding from the bobbin is low. When the unwinding is low, the productivity is reduced and the quality stability of the high-pressure tank is reduced. Therefore, it is considered to add a (meth)acrylate monomer to the resin composition for prepreg in order to reduce the viscosity, but there is a disadvantage that the fracture toughness of the resin composition for prepreg may be reduced. In that case, sufficient durability and impact resistance as a high-pressure tank cannot be ensured. Furthermore, it is considered to use a methyl methacrylate monomer as the (meth)acrylate monomer, but there is a disadvantage that the methyl methacrylate volatilizes during the manufacture of the high-pressure tank. The volatilization reduces the quality stability of the high-pressure tank and there is a risk of ignition. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6610982 [Patent Document 2] Patent Publication No. 2022-22548 Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to provide a resin composition for a tow prepreg capable of realizing a tow prepreg having excellent impregnation property, unwinding property, fracture toughness and heat resistance. Another problem to be solved by the present invention is to provide a tow prepreg having excellent impregnation property, unwinding property, fracture toughness and heat resistance. [Means for solving the problem]

[0008] The resin composition for tow prepreg of the present invention contains a urethane (meth)acrylate resin (A), a (meth)acrylate monomer (B) having a molecular weight of 200 or more and 500 or less, a thermoplastic polyurethane resin (C), a polytetramethylene ether compound (D) having an acrylic or methacrylic group at its terminal, and a polymerization initiator (E), wherein the urethane (meth)acrylate (A) is a reaction product of a polyisocyanate (a1), a polyol (a2) having an aromatic skeleton, and a hydroxyalkyl (meth)acrylate (a3), the (meth)acrylate monomer (B) has a weight loss rate (%) of less than 3 when heated at 50°C under normal pressure for 1 hour, and contains a first (meth)acrylate monomer (b1) having an aromatic skeleton and a second (meth)acrylate monomer (b2) having an alicyclic skeleton, and the molecular weight of the polyether segment of the polytetramethylene ether compound (D) is 1,000 or more and 3,000 or less.

[0009] The tow prepreg of the present invention is characterized in that it contains the above-mentioned resin composition for a tow prepreg and reinforcing fiber bundles, and the reinforcing fiber bundles are impregnated with the resin composition for a tow prepreg. Effect of the Invention

[0010] According to the present invention, there is provided a resin composition for a tow prepreg capable of realizing a tow prepreg having excellent impregnation property, unwinding property, fracture toughness and heat resistance. Furthermore, according to the present invention, there is provided a tow prepreg having excellent impregnation property, unwinding property, fracture toughness and heat resistance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The unsaturated resin composition for prepreg of the present invention contains a urethane (meth)acrylate resin (A), a (meth)acrylate monomer (B) having a molecular weight of 200 or more and 500 or less, a thermoplastic polyurethane resin (C), a polytetramethylene ether compound (D) having an acrylic group or a methacrylic group at its terminal, and a polymerization initiator (E), wherein the urethane (meth)acrylate (A) is a reaction product of a polyisocyanate (a1), a polyol (a2) having an aromatic skeleton, and a hydroxyalkyl (meth)acrylate (a3), the (meth)acrylate monomer (B) has a weight loss rate (%) of less than 3 when heated at 50°C for 1 hour under normal pressure, and contains a first (meth)acrylate monomer (b1) having an aromatic skeleton and a second (meth)acrylate monomer (b2) having an alicyclic skeleton, and the molecular weight of the polyether segment of the polytetramethylene ether compound (D) is 1,000 or more and 3,000 or less.

[0012] The urethane (meth)acrylate resin (A) is a reaction product of a polyisocyanate (a1), a polyol having an aromatic skeleton (a2), and a hydroxyalkyl (meth)acrylate (a3).

[0013] The polyisocyanate (a1) preferably contains a polyisocyanate having an aromatic skeleton or an alicyclic skeleton, since this further improves the heat resistance of the molded article. These polyisocyanates (a1) may be used alone or in combination of two or more kinds.

[0014] Examples of the polyisocyanate (a1) include 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, carbodiimide modified products of 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, nurate modified products, biuret modified products, and urethane imine modified products of diphenylmethane diisocyanate, polyol modified products modified with polyols having a number average molecular weight of 1,000 or less, such as diethylene glycol and dipropylene glycol, tolylene diisocyanate (TDI), tolidin diisocyanate, and the like. aromatic polyisocyanates such as isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, norbornene diisocyanate, and the like; alicyclic polyisocyanates such as hexamethylene diisocyanate, nurate-modified hexamethylene diisocyanate, biuret-modified hexamethylene diisocyanate, adduct, dimer acid diisocyanate, and the like;

[0015] Among these, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, carbodiimide modified products of 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, norbornene diisocyanate, xylylene diisocyanate, and isophorone diisocyanate (IPDI) are preferred because they further improve the heat resistance of molded articles. These polyisocyanates (a1) can be used alone or in combination of two or more kinds.

[0016] The polyol (a2) has an aromatic skeleton. Examples of the polyol include alkylene oxide adducts of bisphenol compounds such as alkylene oxide adducts of bisphenol A, alkylene oxide adducts of bisphenol S, and alkylene oxide adducts of bisphenol F; alkylene oxide adducts of dihydroxybenzene compounds such as 1,3-bis(2-hydroxyethoxy)benzene and 1,4-bis(2-hydroxyethoxy)benzene; alkylene oxide adducts of biphenol compounds such as 2'-[(1,1'-biphenyl-4,4'-diyl)bisoxy]bisethanol; alkylene oxide adducts of dihydroxynaphthalene compounds, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene. Among these, alkylene oxide adducts of bisphenol compounds are preferred from the viewpoint of compatibility, heat resistance, water resistance, and balance of strength properties. More preferred are ethylene oxide adducts of bisphenol compounds, with an average number of moles added being 2 to 10 moles.

[0017] Examples of the hydroxyalkyl (meth)acrylate (a3) ​​include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxy-n-butyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-n-butyl (meth)acrylate, and 3-hydroxy-n-butyl (meth)acrylate. Among these, 2-hydroxyethyl (meth)acrylate is preferred from the viewpoint of the balance of strength properties. These hydroxyalkyl (meth)acrylates (a3) ​​can be used alone or in combination of two or more kinds.

[0018] If necessary, polyols other than the polyols (a2) to (a3) ​​can be used in combination as raw materials for the urethane (meth)acrylate (A). Examples of the other polyols that can be used include polyester polyols, acrylic polyols, polyether polyols, polycarbonate polyols, and polyalkylene polyols.

[0019] The molar ratio (a2 / a3) of the polyol (a2) to the hydroxyalkyl (meth)acrylate (a3) ​​is preferably from 60 / 40 to 20 / 80, and more preferably from 50 / 50 to 30 / 70, in order to further improve heat resistance and curability.

[0020] The molar ratio (NCO / OH) of the isocyanate group (NCO) of the isocyanate compound to the hydroxyl group (OH) of the compound having a hydroxyl group, which are raw materials for the urethane (meth)acrylate (A), is preferably 0.7 to 1.3, more preferably 0.8 to 1.1, and even more preferably 0.8 to 1.0, in view of the balance between heat resistance and strength properties.

[0021] The resin composition for tow prepreg contains a (meth)acrylate monomer (B) having a molecular weight of 200 or more and 500 or less. The (meth)acrylate monomer (B) essentially contains a first (meth)acrylate monomer (b1) having an aromatic skeleton and a weight loss rate (%) of less than 3 when heated at 50°C under normal pressure for 1 hour, and a second (meth)acrylate monomer (b2) having an alicyclic skeleton and a weight loss rate (%) of less than 3 when heated at 50°C under normal pressure for 1 hour.

[0022] The (meth)acrylate monomer (B) has an excellent dilution property for the urethane (meth)acrylate resin (A) and the thermoplastic polyurethane resin (C) due to the molecular weight in the above range, and is suitable for adjusting the viscosity of the resin composition for tow prepregs. In addition, the (meth)acrylate monomer (B) itself is difficult to volatilize due to the molecular weight, so that the viscosity of the resin composition for tow prepregs can be prevented from increasing, and a tow prepreg having excellent impregnation and unwinding properties can be obtained. In addition, when a molded article is produced using the obtained tow prepreg, the volatilization of the (meth)acrylate monomer (B) from the tow prepreg is suppressed, so that the quality stability of the tow prepreg can be ensured, and molded articles can be stably produced, and ignition of the volatile components can be prevented. If the molecular weight of the (meth)acrylate monomer (B) is less than 200, the volatility is high, and the viscosity of the resin composition for tow prepregs can be increased. If the molecular weight of the (meth)acrylate monomer (B) exceeds 500, the viscosity of the resin composition for tow prepregs becomes high. From the viewpoint of heat resistance, the (meth)acrylate monomer (B) is preferably a methacrylate monomer. Furthermore, in consideration of the balance between heat resistance and fracture toughness, the number of functional groups of the unsaturated group in the (meth)acrylate compound is preferably 1 to 2, more preferably 1.

[0023] The (meth)acrylate monomer (B) includes both a first (meth)acrylate monomer (b1) and a second (meth)acrylate monomer (b2) each having a weight loss rate (%) of less than 3 when heated at 50°C under normal pressure for 1 hour. The first (meth)acrylate monomer (b1) and the second (meth)acrylate monomer (b2) satisfy the above molecular weight range and have a weight loss rate of less than 3 and low volatility, so that the viscosity of the resin composition for tow prepregs can be prevented from increasing. A (meth)acrylate monomer having a weight loss rate of more than 3 is undesirable because it volatilizes and causes an increase in the viscosity of the resin composition for tow prepregs. However, it is also possible to add a (meth)acrylate monomer having a weight loss rate of more than 3 within a range that does not cause an increase in the viscosity of the resin composition for tow prepregs.

[0024] The weight loss rate (%) can be measured, for example, as follows. 2.0 to 2.1 g of the (meth)acrylate monomer (B) at room temperature is weighed out and placed in a tinplate petri dish having an inner diameter of about 64 mm, and after leaving it to stand for 1 minute, the petri dish is left to stand on a hot plate with a surface temperature of 50°C under normal pressure for 1 hour. After 1 hour has passed, the petri dish is collected, and after 10 to 20 seconds at room temperature, the weight is measured to four decimal places using a precision balance, and the amount of loss due to heating (%) is calculated to one decimal place. The number of samples N is 2 or more, and the average value is calculated.

[0025] The (meth)acrylate monomer (B) contains both a first (meth)acrylate monomer (b1) having an aromatic skeleton and a second (meth)acrylate monomer (b2) having an alicyclic skeleton. The first (meth)acrylate monomer (b1) has an aromatic skeleton, and therefore has an excellent diluting effect for the urethane (meth)acrylate resin (A), and contributes to a reduction in the viscosity of the resin composition for tow prepregs. The second (meth)acrylate monomer (b2) has an alicyclic skeleton. The alicyclic skeleton has a bulkier structure than the aromatic skeleton, and therefore has a poorer diluting effect than the first (meth)acrylate monomer (b1), but has an excellent effect of improving heat resistance. From these facts, it is believed that a resin composition for tow prepregs having excellent impregnation properties, unwinding properties, and heat resistance can be obtained by using the first (meth)acrylate monomer (b1) and the second (meth)acrylate monomer (b2) in combination. The content ratio (mass ratio) of the first (meth)acrylate (b1) to the second (meth)acrylate monomer is preferably in the range of 20:80 to 60:40, taking into consideration the balance between viscosity and heat resistance.

[0026] When the (meth)acrylate monomer (B) contains the first (meth)acrylate monomer (b1) but does not contain the second (meth)acrylate (b2), a resin composition for tow prepregs having excellent heat resistance cannot be realized.When the (meth)acrylate monomer (B) contains the second (meth)acrylate monomer (b2) but does not contain the first (meth)acrylate (b1), a resin composition for tow prepregs having excellent impregnation and unwinding properties cannot be realized.

[0027] Examples of the first (meth)acrylate monomer (b1) include phenoxyethyl methacrylate, 2-methylphenoxyethyl methacrylate, dimethacrylate of an ethylene oxide adduct of bisphenol A, dimethacrylate of an ethylene oxide adduct of bisphenol F, and 9,9-bis[4-(2-methacryloyloxyethoxy)phenyl]fluorene, with phenoxyethyl methacrylate being preferred. Examples of the second (meth)acrylate monomer (b2) include tricyclo[5.2.1.0(2,6)]decan-8-yl-(meth)acrylate (commonly known as "dicyclopentanyl (meth)acrylate"), bornyl methacrylate, isobornyl methacrylate, adamantyl (meth)acrylate, 4-t-butylcyclohexyl methacrylate, glycerol carbonate methacrylate, hydrogenated bisphenol A dimethacrylate, tricyclodecane dimethanol dimethacrylate, dimethacrylate of an ethylene oxide adduct of isosorbide, and an ethylene oxide adduct of hydrogenated bisphenol A. Of these, tricyclo[5.2.1.0(2,6)]decan-8-yl-methacrylate (commonly known as "dicyclopentanyl methacrylate") and isobornyl methacrylate are preferred.

[0028] In addition, the total content of the first (meth)acrylate monomer (b1) and the second (meth)acrylate monomer (b2) in the resin composition for tow prepregs is preferably 30 to 60 mass % based on the total mass of the urethane (meth)acrylate resin (A), the (meth)acrylate monomer (B) and the thermoplastic polyurethane resin (C) in order to further improve the balance between resin impregnation, productivity and quality of molded products during the production of tow prepregs, and is more preferably 35 to 55 mass %, and even more preferably 35 to 50 mass %, in view of the balance between resin viscosity during impregnation and fracture toughness.

[0029] The thermoplastic polyurethane resin (C) is preferably a thermoplastic polyurethane made mainly of polyalkylene ether polyol. These thermoplastic polyurethane resins can be used alone or in combination of two or more. A thermoplastic polyurethane resin made mainly of polytetramethylene ether glycol is more preferable because it can provide a molded product with higher strength and toughness. The molecular weight of the thermoplastic polyurethane resin (C) is preferably 10,000 to 100,000 in weight average.

[0030] The amount of the thermoplastic polyurethane resin (C) added is preferably within a range of 2 to 10 parts by mass per 100 parts by mass of the total of the urethane (meth)acrylate resin (A), the (meth)acrylate monomer (B), and the thermoplastic polyurethane resin (C), in terms of the balance between fracture toughness and liquid stability of the resin liquid.

[0031] The resin composition for tow prepregs contains a polytetramethylene ether compound (D) having an acrylic group or a methacrylic group at its terminal, and the molecular weight of the polyether segment of the polytetramethylene ether compound (D) is 1000 or more and 3000 or less. The molecular weight is more preferably 1500 or more and 2500 or less. The molecular weight of the polyether segment refers to the molecular weight of polytetramethylene ether glycol used as a raw material, and a value calculated from the following formula (1) is used. Molecular weight of polyether segment = (hydroxyl equivalent of polytetramethylene ether glycol) x 2 Formula (1)

[0032] By using the polytetramethylene ether compound (D) having a molecular weight within the above range, it is not possible to obtain a tow prepreg resin composition having excellent fracture toughness and heat resistance. If the molecular weight of the segment is less than 1,000, it is not possible to increase the heat resistance, and if the molecular weight of the segment is more than 3,000, it is not possible to increase the fracture toughness.

[0033] Examples of the polytetramethylene ether compound (D) include di(meth)acrylate obtained by reacting polytetramethylene ether glycol with (meth)acrylic acid, (meth)acrylic acid ester, or (meth)acrylic acid anhydride, and purifying the resulting mixture, urethane (meth)acrylate obtained by reacting polytetramethylene ether glycol with a diisocyanate compound and 2-hydroxyethyl (meth)acrylate, and di(meth)acrylate obtained by reacting polytetramethylene ether glycol with 2-isocyanatoethyl (meth)acrylate. Among these, polytetramethylene ether glycol di(meth)acrylate is preferred because it can provide a cured resin with higher fracture toughness and can reduce the viscosity of the resin composition before curing. The polytetramethylene ether compound (D) may be used alone or in combination of two or more.

[0034] From the viewpoint of the balance between fracture toughness and heat resistance (glass transition temperature Tg), the content of the polytetramethylene ether compound (D) in the resin composition for tow prepreg is preferably 1 to 20 parts by mass, and more preferably 3 to 18 parts by mass, per 100 parts by mass of the total of the urethane (meth)acrylate resin (A), the (meth)acrylate monomer (B), and the thermoplastic polyurethane resin (C).

[0035] The polymerization initiator (E) is not particularly limited, but is preferably an organic peroxide, such as a diacyl peroxide compound, a peroxy ester compound, a hydroperoxide compound, a ketone peroxide compound, an alkyl perester compound, a percarbonate compound, a peroxy ketal, etc., and can be appropriately selected according to the molding conditions. These polymerization initiators (E) can be used alone or in combination of two or more kinds. A photopolymerization initiator may also be used in combination.

[0036] For the purpose of shortening the molding time, it is preferable to use, as the polymerization initiator (E), a polymerization initiator having a temperature for obtaining a 10-hour half-life of 60° C. or more and 110° C. or less. If the temperature is 70° C. or more and 105° C. or less, the prepreg has a long life at room temperature and can be cured in a short time (within 5 minutes) by heating, which is preferable, and by using it in the prepreg of the present invention, the curability and moldability are more excellent. Examples of such polymerization initiators include 1,6-bis(t-butylperoxycarbonyloxy)hexane, 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-amylperoxy)cyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, t-butylperoxydiethyl acetate, t-butylperoxyisopropyl carbonate, t-butylperoxy2-ethylhexyl carbonate, t-amylperoxyisopropyl carbonate, t-amylperoxy2-ethylhexyl carbonate, t-hexylperoxyisopropyl carbonate, di-tert-butylperoxyhexahydroterephthalate, t-amylperoxytrimethylhexanoate, t-amylperoxyisononaate, t-hexylperoxy-2-ethylhexanoate, and n-butyl 4,4-di(t-butylperoxy)valerate. The most suitable organic peroxide is selected and used according to the molding conditions.

[0037] The amount of the polymerization initiator (E) added is preferably within a range of 0.5 to 4 parts by mass per 100 parts by mass of the total of the urethane (meth)acrylate resin (A), the (meth)acrylate monomer (B), and the thermoplastic polyurethane resin (C), since this provides excellent curing characteristics and storage stability.

[0038] The heating temperature when the resin composition for tow prepregs is impregnated into the tow depends on the capacity of the tow prepreg manufacturing equipment, but is preferably about 30 to 60°C, and from the viewpoint of preventing abnormal decomposition of the peroxide and reducing the viscosity at the same time, it is more preferably about 40 to 50°C. From the viewpoint of productivity during towpreg manufacturing, the viscosity of the resin composition for tow prepregs is preferably in the range of 0.1 to 5 Pa·S at a temperature range of 30 to 60°C. The resin composition is finely adjusted so that the viscosity of the resin composition for tow prepregs falls within the above range.

[0039] The resin composition for tow prepregs of the present invention may contain components other than those mentioned above. For example, the resin composition may contain a thermosetting resin, a thermoplastic resin, a polymerization inhibitor, a curing accelerator, a filler, a low shrinkage agent, a release agent, a thickener, a viscosity reducer, a pigment, an antioxidant, a plasticizer, a flame retardant, an antibacterial agent, an ultraviolet stabilizer, a reinforcing material, a photopolymerization initiator, etc.

[0040] Examples of the thermosetting resin include vinyl ester resin, unsaturated polyester resin, epoxy resin, bismaleimide resin, etc. These thermosetting resins can be used alone or in combination of two or more kinds.

[0041] Examples of the thermoplastic resin include polyamide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polycarbonate resin, polyurethane resin, polypropylene resin, polyethylene resin, polystyrene resin, acrylic resin, polybutadiene resin, polyisoprene resin, and those modified by copolymerization. Among these, polyamide resin and polyurethane resin are preferred because they have a high effect of improving brittleness. These thermoplastic resins can be used alone or in combination of two or more. Thermoplastic resins can be added in particulate form or melted and mixed. When particulate thermoplastic resins are used, the particle size is preferably 30 μm or less, more preferably 5 to 20 μm, from the viewpoint of dispersibility in fibers.

[0042] Examples of the polymerization inhibitor include hydroquinone, trimethylhydroquinone, pt-butylcatechol, t-butylhydroquinone, toluhydroquinone, p-benzoquinone, naphthoquinone, hydroquinone monomethyl ether, phenothiazine, copper naphthenate, copper chloride, etc. These polymerization inhibitors can be used alone or in combination of two or more kinds.

[0043] The fillers include inorganic compounds and organic compounds, and can be used to adjust the physical properties of the molded product, such as strength, elastic modulus, impact strength, and fatigue durability.

[0044] Examples of the inorganic compound include calcium carbonate, magnesium carbonate, barium sulfate, mica, talc, kaolin, clay, celite, asbestos, barite, baryta, silica, silica sand, dolomite limestone, gypsum, aluminum fine powder, hollow balloons, alumina, glass powder, aluminum hydroxide, kansuiite, zirconium oxide, antimony trioxide, titanium oxide, molybdenum dioxide, and iron powder.

[0045] The organic compounds include natural polysaccharide powders such as cellulose and chitin, and synthetic resin powders. As the synthetic resin powders, organic powders composed of hard resins, soft rubbers, elastomers, polymers (copolymers), and particles having a multilayer structure such as a core-shell type can be used. Specific examples include acrylic particles, polyamide particles, particles composed of butadiene rubber and / or acrylic rubber, urethane rubber, silicone rubber, polyimide resin powders, fluororesin powders, and phenolic resin powders. These fillers can be used alone or in combination of two or more.

[0046] Examples of the release agent include zinc stearate, calcium stearate, paraffin wax, polyethylene wax, carnauba wax, etc. Preferred are paraffin wax, polyethylene wax, carnauba wax, etc. These release agents can be used alone or in combination of two or more kinds.

[0047] The thickener may be, for example, a polyisocyanate compound, an acrylic resin-based fine particle, etc., and may be appropriately selected depending on the handling property of the tow prepreg of the present invention. These thickeners may be used alone or in combination of two or more kinds.

[0048] The photopolymerization initiator is a polymerization initiator that generates radicals by irradiation with light, and any known photopolymerization initiator can be used without particular limitation. As the photopolymerization initiator, an alkylphenone radical initiator, a benzophenone radical initiator, a benzoin radical initiator, an acylphosphine oxide radical initiator, or the like is preferred because it is easily available.

[0049] The resin composition for tow prepreg is prepared by mixing the urethane (meth)acrylate resin (A), the (meth)acrylate monomer (B), the thermoplastic polyurethane resin (C), the polytetramethylene ether compound (D) having an acrylic or methacrylic group at the end, and the polymerization initiator (E). For example, when producing the urethane (meth)acrylate (A), a method in which the polyol (a2) having an aromatic skeleton, the thermoplastic polyurethane resin (C), and the hydroxyalkyl (meth)acrylate (a3) ​​are mixed in advance, and then the polyisocyanate (a1) is added and reacted to obtain a mixture of the urethane (meth)acrylate resin (A) and the thermoplastic polyurethane resin (C) is desirable because of its excellent mass productivity.

[0050] The above-mentioned resin composition for a tow prepreg is impregnated into a reinforcing fiber bundle and used as a tow prepreg. That is, the tow prepreg of the present invention is characterized in that it contains the above-mentioned resin composition for a tow prepreg and a reinforcing fiber bundle, and the reinforcing fiber bundle is impregnated with the resin composition for a tow prepreg.

[0051] Examples of the fibers of the reinforcing fiber bundle include carbon fibers, glass fibers, silicon carbide fibers, alumina fibers, boron fibers, metal fibers, and organic fibers such as aramid fibers, vinylon fibers, and tetron fibers. Carbon fibers, glass fibers, and aramid fibers are preferred because they provide molded products with higher strength and elasticity, and carbon fibers are more preferred for producing high-pressure tanks for storing natural gas, hydrogen gas, etc. These reinforcing fibers can be used alone or in combination of two or more types.

[0052] As the carbon fiber, various types of fibers such as polyacrylonitrile, pitch, and rayon can be used. Among these, polyacrylonitrile-based fibers are preferred because they can easily produce high-strength carbon fibers.

[0053] The shape of the reinforcing fibers is not particularly limited, and examples thereof include reinforcing fiber tows in which reinforcing fiber filaments are bundled, unidirectional materials in which reinforcing fiber tows are aligned in one direction, and reinforcing fibers woven into a woven fabric. As a tow prepreg, the use of reinforcing fiber tows, lamination and molding, is preferable because high mechanical properties can be obtained.

[0054] The content of the reinforcing fiber bundles in the tow prepreg of the present invention is preferably in the range of 50 to 85% by mass, more preferably in the range of 60 to 80% by mass, since this further improves the mechanical strength of the resulting molded article.

[0055] The tow prepreg of the present invention can be produced by various known methods, but a production method that does not use any diluting solvent is preferable. Specifically, the unsaturated resin composition of the present invention is heated to reduce its viscosity, contacted with a reinforcing fiber bundle aligned in one direction in a resin bath or coater, and further impregnated with the resin while being pressed and bonded by a rotating roll, and then wound up on a bobbin or the like.

[0056] As a method for obtaining a molded product from the obtained tow prepreg, for example, the tow prepreg wound around a bobbin or the like is unwound, wound around a resin or metal liner, and then a shrink film or the like is wound on the surface, followed by heating and curing in an oven or the like, to produce a molded product such as a gas tank. Also, a fiber-reinforced metal member can be produced by winding the tow prepreg around a metal rod, a pipe, or the like, and then performing a similar process and heating and curing. Examples of such materials include spindle shafts, rotating rolls, and power transmission shafts. The combination and configuration can be appropriately selected depending on the product. The tow prepreg using the resin composition for tow prepreg of the present invention has excellent unwinding properties when unwound from a bobbin or the like, and therefore has high productivity and can ensure the quality stability of the molded product. In addition, the tow prepreg using the resin composition for tow prepreg of the present invention has no risk of volatilization of the (meth)acrylate monomer (B) contained in the resin composition, and therefore the quality stability of the tow prepreg can be ensured, and thus molded products can be stably produced, and ignition of the volatile components can be prevented.

[0057] Molded articles obtained from the prepreg of the present invention have excellent fracture toughness and heat resistance, and therefore can be suitably used for automobile parts, railway car parts, aerospace aircraft parts, ship parts, housing equipment parts, sports parts, light vehicle parts, building and civil engineering parts, and in particular, high-pressure tanks for storing natural gas, hydrogen gas, etc. EXAMPLES

[0058] The present invention will now be described in more detail with reference to specific examples.

[0059] (Synthesis Example 1: Production of Thermoplastic Polyurethane Resin (C-1)) 710 g of PTMG1000 (Mitsubishi Chemical Corporation: polytetramethylene ether glycol, hydroxyl equivalent: 505 g / eq), 30 g of 1,4-butanediol, and 260 g of 4,4'-diphenylmethane diisocyanate were mixed in a round can, then cast onto a stainless steel tray and reacted at 90°C for 24 hours to produce a thermoplastic polyurethane resin (C-1). The weight average molecular weight of the thermoplastic polyurethane resin (C-1) was 50,000.

[0060] (Synthesis Example 2: Production of polytetramethylene ether compound (D-1) having an acrylic or methacrylic group at the end) In a 0.5L flask equipped with a thermometer, nitrogen and air inlet tubes, and a stirrer, 100g of PTMG1000 (manufactured by Mitsubishi Chemical Corporation: polytetramethylene ether glycol, hydroxyl equivalent: 505g / eq), 33g of methacrylic anhydride, 0.03g of t-butyl hydroquinone, and 0.5g of dimethylaminopyridine were added and mixed, and the temperature was raised to 100°C under a gas flow of a 1:1 mixture of nitrogen and air. After holding at 100°C for 4 hours, the mixture was cooled to 80°C, and 200g of toluene was added to make a homogeneous solution, and then 100g of 10% by weight aqueous sodium hydrogen carbonate solution was gradually added and stirred for 1 hour. The entire contents were transferred to a separatory funnel, the aqueous phase and the organic phase were separated, and the aqueous phase was removed. 100g of 10% by weight aqueous sodium hydrogen carbonate solution was gradually added to the obtained organic phase again, and the mixture was shaken and stirred. The aqueous phase and the organic phase were separated, and the remaining organic phase after removing the aqueous phase was transferred to a 0.5 L flask again, and subjected to reduced pressure desolvation treatment at 95°C for 2 hours, and the pressure was returned to normal pressure and the contents were taken out. The obtained contents contain a polytetramethylene ether compound (D-1) having a methacryl group at the end. The molecular weight of the polyether segment of the compound (D-1) was calculated from the hydroxyl group equivalent of the raw material using formula (1) and was 1010. The hydroxyl value of the compound (D-1) was 2 mgKOH / g.

[0061] (Synthesis Example 3: Production of polytetramethylene ether compound (D-2) having an acrylic or methacrylic group at the end) In the 0.5L flask, 100g of PTMG2000 (manufactured by Mitsubishi Chemical Corporation: polytetramethylene ether glycol, hydroxyl equivalent: 975g / eq), 17g of methacrylic anhydride, 0.03g of t-butyl hydroquinone, and 0.4g of dimethylaminopyridine were added and mixed, and the temperature was raised to 100°C under a gas flow of a 1:1 mixture of nitrogen and air. After holding at 100°C for 4 hours, the mixture was cooled to 80°C, and 200g of toluene was added to make a homogeneous solution, and then 100g of a 10% by weight aqueous solution of sodium bicarbonate was gradually added and stirred for 1 hour. The entire contents were transferred to a separatory funnel, and the aqueous phase and organic phase were separated, and the aqueous phase was removed. The remaining organic phase was transferred again to a 0.5L flask, and a reduced pressure desolvation treatment was performed at 95°C for 2 hours, and the pressure was returned to normal pressure, and the contents were removed. The obtained contents contained a polytetramethylene ether compound (D-2) having a methacryl group at its end. The molecular weight of the glycol as a segment of the compound (D-2) was 1950. The hydroxyl value of the compound (D-2) was 1 mgKOH / g.

[0062] (Synthesis Example 4: Production of polytetramethylene ether compound (D-3) having an acrylic or methacrylic group at the end) In the 0.5L flask, 100g of PTMG3000 (manufactured by Mitsubishi Chemical Corporation: polytetramethylene ether glycol, hydroxyl equivalent: 1435g / eq), 12g of methacrylic anhydride, 0.03g of t-butyl hydroquinone, and 0.4g of dimethylaminopyridine were added and mixed, and the temperature was raised to 100°C under a gas flow of a 1:1 mixture of nitrogen and air. After holding at 100°C for 4 hours, the mixture was cooled to 80°C, and 200g of toluene was added to make a homogeneous solution, and then 100g of a 7% by weight aqueous sodium hydrogen carbonate solution was gradually added and stirred for 1 hour. The entire contents were transferred to a separatory funnel, and the aqueous phase and organic phase were separated, and the aqueous phase was removed. The remaining organic phase was transferred again to a 0.5L flask, and a reduced pressure desolvation treatment was performed at 95°C for 2 hours, and the pressure was returned to normal pressure, and the contents were removed. The obtained contents contained a polytetramethylene ether compound (D-3) having a methacryl group at its end. The molecular weight of the glycol as a segment of the compound (D-3) was 2870. The hydroxyl value of the compound (D-3) was 0 mgKOH / g.

[0063] (Synthesis Example 5: Production of polytetramethylene ether compound (D-4) having an acrylic or methacrylic group at the end) In the 0.5L flask, 100g of PTMG20000 (manufactured by Mitsubishi Chemical Corporation: polytetramethylene ether glycol, hydroxyl equivalent: 975g / eq), 23g of isophorone diisocyanate, 0.03g of t-butyl hydroquinone, and 0.1g of 1,4-diazabicyclo[2.2.2]octane were added and mixed, and the temperature was raised to 60°C under a gas flow of a 1:1 mixture of nitrogen and air. After holding at 60°C for 1 hour, 13.5g of hydroxyethyl methacrylate was charged and the temperature was raised to 80°C in 30 minutes. After holding at 80°C for 4 hours, the mixture was cooled to 60°C and the contents were removed. The obtained contents contained a polytetramethylene ether compound (D-4) having a methacryl group at its end. The molecular weight of the glycol as a segment of the compound (D-4) was 1950. The compound (D-4) had a hydroxyl value of 0 mgKOH / g.

[0064] (Synthesis Example 6: Production of polytetramethylene ether compound (D'-1) having an acrylic or methacrylic group at its terminal) In the 0.5L flask, 100g of PTMG4000 (manufactured by Mitsubishi Chemical Corporation: polytetramethylene ether glycol, hydroxyl equivalent: 1915g / eq), 9g of methacrylic anhydride, 0.03g of t-butyl hydroquinone, and 0.4g of dimethylaminopyridine were added and mixed, and the temperature was raised to 100°C under a gas flow of a 1:1 mixture of nitrogen and air. After holding at 100°C for 4 hours, the mixture was cooled to 80°C, and 200g of toluene was added to make a homogeneous solution, and then 100g of a 3% by weight aqueous solution of sodium bicarbonate was gradually added and stirred for 1 hour. The entire contents were transferred to a separatory funnel, and the aqueous phase and organic phase were separated, and the aqueous phase was removed. The remaining organic phase was transferred again to a 0.5L flask, and a reduced pressure desolvation treatment was performed at 95°C for 2 hours, and the pressure was returned to normal pressure, and the contents were removed. The obtained contents contained a polytetramethylene ether compound (D'-1) having a methacryl group at its end. The molecular weight of the glycol as a segment of the compound (D'-1) was 3830. The hydroxyl value of the compound (D'-1) was 0 mgKOH / g.

[0065] (Synthesis Example 7: Production of resin mixture (AC-1) of urethane (meth)acrylate resin (A-1) and thermoplastic urethane resin (C-1)) In a 5L flask equipped with a thermometer, nitrogen and air inlet tubes, and a stirrer, 423g of Newpol BPE-20 (manufactured by Sanyo Chemical Industries, Ltd.: EO adduct of bisphenol A, hydroxyl equivalent: 161g / eq) and 534g of Newpol BPE-40 (manufactured by Sanyo Chemical Industries, Ltd.: EO adduct of bisphenol A, hydroxyl equivalent: 203g / eq) were added, and after uniform mixing at 100°C, the mixture was heated to 140°C, and 379g of the thermoplastic resin (C-1) was added in three portions and mixed with stirring for 6 hours. After confirming that the mixture was dissolved uniformly, the mixture was cooled to 120°C, and 1025g of hydroxyethyl methacrylate and 0.9g of t-butyl hydroquinone were added, and the mixture was stirred at 90°C for 1 hour, and then cooled to 40°C. Next, 492 g of 4,4'-diphenylmethane diisocyanate was added in two portions, and one hour later, 984 g of 2,4'-diphenylmethane diisocyanate was added in four portions, and the temperature was raised to 80°C while paying attention to heat generation. After 4 hours at 80°C, the contents were removed from the reaction vessel. As a result, a resin mixture (AC-1) of urethane (meth)acrylate resin (A-1) and thermoplastic urethane resin (C-1) was obtained. The resin mixture (AC-1) contains 90.2 parts by mass of the urethane (meth)acrylate resin (A-1) and 9.8 parts by mass of the thermoplastic urethane resin (C-1) per 100 parts by mass.

[0066] (Example 1: Preparation and evaluation of resin composition for tow prepreg (X-1)) NK ester as the first (meth)acrylate monomer (b1-1) having an aromatic backbone A resin composition for tow prepreg (X-1) was obtained by mixing 15 parts by mass of PEM-100 (manufactured by Shin-Nakamura Chemical Co., Ltd., phenoxyethyl methacrylate, molecular weight 206, weight loss rate when heated at normal pressure at 50°C for 1 hour 0.7%), 25 parts by mass of FA-513M (manufactured by Resonac Inc., dicyclopentanyl methacrylate, molecular weight 220, purity 98.3%, weight loss rate when heated at normal pressure at 50°C for 1 hour 1.7%) as a second (meth)acrylate monomer (b2-1) having an alicyclic skeleton, 60 parts by mass of the resin mixture (AC-1), 4 parts by mass of the polytetramethylene ether compound (D-1), 0.02 parts by mass of parabenzoquinone, and 1.1 parts by mass of a polymerization initiator (E-1) (manufactured by Nouryon Chemical Co., Ltd., "Trigonox 122-C80", organic peroxide). The first (meth)acrylate monomer (b1-1) and the second (meth)acrylate monomer (b2-1) each correspond to the (meth)acrylate monomer (B) having a molecular weight of 200 or more and 500 or less.

[0067] In the resin composition (X-1), the total content of the first (meth)acrylate monomer (b1-1) and the second (meth)acrylate monomer (b2-1) is 40 mass% based on the total mass of the urethane (meth)acrylate resin (A-1), the (meth)acrylate monomer (B) having a molecular weight of 200 to 500, and the thermoplastic urethane resin (C-1). In addition, in the resin composition (X-1), the content of the polytetramethylene ether compound (D-1) is 4 parts by mass based on 100 parts by mass of the total mass of the urethane (meth)acrylate resin (A-1), the thermoplastic urethane resin (C-1), and the (meth)acrylate monomer (B) having a molecular weight of 200 to 500.

[0068] [Evaluation of impact resistance of cured resin plate] The obtained resin composition (X-1) was poured between glass plates with a gap of 6 mm, heated from room temperature to 150°C in 1.5 hours in a heating furnace, held at 150°C for 1 hour, cooled to 80°C in 30 minutes, and then allowed to cool at room temperature to obtain a cured resin for prepreg with a thickness of 6 mm. The obtained cured product was cut into a width of 12.7 mm and a length of 55 mm with a diamond cutter, and a precrack was introduced. Thereafter, the number of samples n=10 was set according to ASTM D5045-99, and the fracture toughness value (K IC ) was measured and evaluated according to the following criteria. ○: 1.8 (MPa m 0.5 ) End △:1.5 or more, 1.8 (MPa m 0.5 )less than ×:1.5(MPa m 0.5 )less than

[0069] [Evaluation of heat resistance of cured resin plate] The resin composition (X-1) was poured between glass plates with a gap of 4 mm, heated from room temperature to 150°C in a heating furnace over 1.5 hours, held at 150°C for 1 hour, cooled to 80°C over 30 minutes, and allowed to cool at room temperature to obtain a cured resin for prepreg with a thickness of 4 mm. The obtained cured product was cut into a width of 10 mm and a length of 45 mm using a diamond cutter, and dynamic viscoelasticity was measured in a temperature range of 10 to 200°C using a TA Instruments "RSA-G2" at a measurement frequency of 1 Hz, a heating rate of 5°C / min, and a three-point bending mode. In the obtained storage modulus E', the intersection of the approximation line of the glass region and the tangent line of the transition region was taken as the glass transition temperature (Tg), and the heat resistance was evaluated according to the following criteria. ○: 115℃ or higher △: 105℃ or higher, less than 115℃ ×: Less than 105℃

[0070] [Production of tow prepreg] A tow prepreg was produced as follows using the obtained resin composition (X-1) and high-strength carbon fibers T700SC-12K (manufactured by Toray Industries, Inc.) as reinforcing fiber bundles. Using a tow prepreg manufacturing apparatus equipped with a creel, a resin bath, an impregnation roll, a nip roll, a winder, and a tension controller, resin composition (X-1) adjusted to a temperature of 50°C was applied to one side of a unidirectional reinforcing fiber bundle so that the content of resin composition (X-1) in the tow prepreg was 24 mass%, and the reinforcing fiber bundle was impregnated with the resin composition (X-1) to the inside by passing it through a nip roll. The apparatus was operated at 20 m / min for 1 hour, to obtain a tow prepreg (1). The obtained tow prepreg (1) was wrapped in an oxygen barrier film, placed in a bag made of oxygen barrier film, purged with nitrogen, sealed, and allowed to stand at room temperature.

[0071] [Evaluation of resin impregnation of tow prepreg] The obtained tow prepreg (1) was taken out 7 days after production and evaluated by visual observation. ◯: Both sides of the reinforcing fiber bundle are uniformly impregnated. △: A small amount of unimpregnated fibers are observed on both sides of the reinforcing fiber bundle. ×: Both sides of the reinforcing fiber bundle are not uniform, and unimpregnated fibers are present.

[0072] [Evaluation of the unwinding property of tow prepreg] The tow prepreg (1) obtained above was taken out 7 days after production, fixed to a creel, the tip of the tow prepreg was wound around an empty bobbin, and unwound at a speed of 30 m / min. The unwinding condition at that time was evaluated. ◯: The tow prepreg could be pulled out to the end, and the bobbin rotation speed was stable from start to finish. △: The tow prepreg could be pulled out to the end, but the bobbin rotation speed was unstable. ×: The tow prepreg was strongly attached to the bobbin, and the tow prepreg could not be stably unwound.

[0073] (Example 2: Preparation and evaluation of resin composition for tow prepreg (X-2)) A resin composition for tow prepreg (X-2) was obtained in the same manner as in Example 1, except that the amount of the polytetramethylene ether compound (D-1) added was changed to 8 parts by mass. A resin molded plate and a tow prepreg (2) were produced in the same manner as in Example 1, except that the resin composition (X-2) obtained was used, and each evaluation was performed.

[0074] (Example 3: Preparation and evaluation of resin composition for tow prepreg (X-3)) A resin composition for tow prepreg (X-3) was obtained in the same manner as in Example 1, except that the amount of the polytetramethylene ether compound (D-1) added was changed to 14 parts by mass. A resin molded plate and a tow prepreg (3) were produced in the same manner as in Example 1, except that the resin composition (X-3) obtained was used, and each evaluation was performed.

[0075] (Example 4: Preparation and evaluation of resin composition for tow prepreg (X-4)) A resin composition for tow prepreg (X-4) was obtained in the same manner as in Example 1, except that 4 parts by mass of the polytetramethylene ether compound (D-2) was used instead of the polytetramethylene ether compound (D-1). A resin molded plate and a tow prepreg (4) were produced in the same manner as in Example 1, except that the resin composition (X-4) obtained was used, and each evaluation was performed.

[0076] (Example 5: Preparation and evaluation of resin composition for tow prepreg (X-5)) A resin composition for tow prepreg (X-5) was obtained in the same manner as in Example 1, except that 8 parts by mass of the polytetramethylene ether compound (D-2) was used instead of the polytetramethylene ether compound (D-1). A resin molded plate and a tow prepreg (5) were produced in the same manner as in Example 1, except that the resin composition (X-5) obtained was used, and each evaluation was performed.

[0077] (Example 6: Preparation and evaluation of resin composition for tow prepreg (X-6)) A resin composition for tow prepreg (X-6) was obtained in the same manner as in Example 1, except that 14 parts by mass of the polytetramethylene ether compound (D-2) was used instead of the polytetramethylene ether compound (D-1). A resin molded plate and a tow prepreg (6) were produced in the same manner as in Example 1, except that the resin composition (X-6) obtained was used, and each evaluation was performed.

[0078] (Example 7: Preparation and evaluation of resin composition for tow prepreg (X-7)) A resin composition for tow prepreg (X-7) was obtained in the same manner as in Example 1, except that 8 parts by mass of the polytetramethylene ether compound (D-3) was used instead of the polytetramethylene ether compound (D-1). A resin molded plate and a tow prepreg (7) were produced in the same manner as in Example 1, except that the resin composition (X-7) obtained was used, and each evaluation was performed.

[0079] (Example 8: Preparation and evaluation of resin composition for tow prepreg (X-8)) A resin composition for tow prepreg (X-8) was obtained in the same manner as in Example 1, except that 14 parts by mass of the polytetramethylene ether compound (D-3) was used instead of the polytetramethylene ether compound (D-1). A resin molded plate and a tow prepreg (8) were produced in the same manner as in Example 1, except that the resin composition (X-8) obtained was used, and each evaluation was performed.

[0080] (Example 9: Preparation and evaluation of resin composition for tow prepreg (X-9)) A resin composition for tow prepreg (X-9) was obtained in the same manner as in Example 5, except that the amount of the first (meth)acrylate monomer (b1-1) added was changed to 10 parts by mass, and the amount of the second (meth)acrylate monomer (b2-1) added was changed to 30 parts by mass. A resin molded plate and a tow prepreg (9) were produced in the same manner as in Example 1, except that the resin composition (X-9) obtained was used, and each evaluation was performed.

[0081] (Example 10: Preparation and evaluation of resin composition for tow prepreg (X-10)) A resin composition for tow prepreg (X-10) was obtained in the same manner as in Example 5, except that the amount of the first (meth)acrylate monomer (b1-1) added was changed to 20 parts by mass, and the amount of the second (meth)acrylate monomer (b2-1) added was changed to 20 parts by mass. A resin molded plate and a tow prepreg (10) were produced in the same manner as in Example 1, except that the obtained resin composition (X-10) was used, and each evaluation was performed.

[0082] (Example 11: Preparation and evaluation of resin composition for tow prepreg (X-11)) The same procedure as in Example 5 was carried out to obtain a resin composition for tow prepreg (X-11), except that the amount of the first (meth)acrylate monomer (b1-1) added was changed to 20 parts by mass, and 20 parts by mass of acrylic ester IBX (manufactured by Mitsubishi Chemical Corporation, isobornyl methacrylate, molecular weight 222, weight loss rate when heated at 50°C for 1 hour under normal pressure: 1.5%) was added as the second (meth)acrylate monomer (b2-2) instead of the second (meth)acrylate monomer (b2-1). A resin molded plate and a tow prepreg (11) were produced and evaluated in the same manner as in Example 1, except that the resin composition (X-11) obtained was used.

[0083] (Example 12: Preparation and evaluation of resin composition for tow prepreg (X-12)) A resin composition for tow prepreg (X-12) was obtained in the same manner as in Example 5, except that the amount of the first (meth)acrylate monomer (b1-1) added was changed to 10 parts by mass, and 30 parts by mass of the second (meth)acrylate monomer (b2-2) was added instead of the second (meth)acrylate monomer (b2-1). A resin molded plate and a tow prepreg (12) were produced in the same manner as in Example 1, except that the resin composition (X-12) obtained was used, and each evaluation was performed.

[0084] (Example 13: Preparation and evaluation of resin composition for tow prepreg (X-13)) A resin composition for tow prepreg (X-13) was obtained in the same manner as in Example 5, except that the amount of the first (meth)acrylate monomer (b1-1) added was changed to 20 parts by mass, the amount of the second (meth)acrylate monomer (b2-1) added was changed to 10 parts by mass, and 10 parts by mass of the second (meth)acrylate monomer (b2-2) was further added. A resin molded plate and a tow prepreg (13) were produced in the same manner as in Example 1, except that the obtained resin composition (X-13) was used, and each evaluation was performed.

[0085] (Example 14: Preparation and evaluation of resin composition for tow prepreg (X-14)) A resin composition for tow prepreg (X-14) was obtained in the same manner as in Example 5, except that the amount of the resin mixture (AC-1) was changed from 60 parts by mass to 50 parts by mass, the amount of the first (meth)acrylate monomer (b1-1) was changed to 20 parts by mass, and the amount of the second (meth)acrylate monomer (b2-1) was changed to 30 parts by mass. A resin molded plate and a tow prepreg (14) were produced in the same manner as in Example 1, except that the resin composition (X-14) obtained was used, and each evaluation was performed.

[0086] (Example 15: Preparation and evaluation of resin composition for tow prepreg (X-15)) A resin composition for tow prepreg (X-15) was obtained in the same manner as in Example 5, except that the amount of the resin mixture (AC-1) was changed from 60 parts by mass to 65 parts by mass, and the amount of the second (meth)acrylate monomer (b2-1) added was changed to 20 parts by mass. A resin molded plate and a tow prepreg (15) were produced in the same manner as in Example 1, except that the resin composition (X-15) obtained was used, and each evaluation was performed.

[0087] (Example 16: Preparation and evaluation of resin composition for tow prepreg (X-16)) A resin composition for tow prepreg (X-16) was obtained in the same manner as in Example 5, except that 8 parts by mass of the polytetramethylene ether compound (D-4) was used instead of the polytetramethylene ether compound (D-1). A resin molded plate and a tow prepreg (16) were produced in the same manner as in Example 1, except that the resin composition (X-16) obtained was used, and each evaluation was performed.

[0088] (Example 17: Preparation and evaluation of resin composition for tow prepreg (X-17)) A resin composition for tow prepreg (X-17) was obtained in the same manner as in Example 5, except that the amount of the resin mixture (AC-1) was changed from 60 parts by mass to 40 parts by mass, the amount of the first (meth)acrylate monomer (b1-1) was changed to 25 parts by mass, and the amount of the second (meth)acrylate monomer (b2-1) was changed to 35 parts by mass. A resin molded plate and a tow prepreg (17) were produced in the same manner as in Example 1, except that the resin composition (X-17) obtained was used, and each evaluation was performed.

[0089] (Example 18: Preparation and evaluation of resin composition for tow prepreg (X-18)) A resin composition for tow prepreg (X-18) was obtained in the same manner as in Example 5, except that the amount of the resin mixture (AC-1) was changed from 60 parts by mass to 70 parts by mass, and the amount of the second (meth)acrylate monomer (b2-1) added was changed to 15 parts by mass. A resin molded plate and a tow prepreg (18) were produced in the same manner as in Example 1, except that the resin composition (X-18) obtained was used, and each evaluation was performed.

[0090] (Comparative Example 1: Preparation and Evaluation of Resin Composition for Tow Prepreg (RX-1)) A resin composition for tow prepreg (RX-1) was obtained in the same manner as in Example 5, except that the polytetramethylene ether compound (D-1) was not added at all. A resin molded plate and a tow prepreg (R1) were produced in the same manner as in Example 1, except that the obtained resin composition (RX-1) was used, and each evaluation was performed.

[0091] (Comparative Example 2: Preparation and Evaluation of Resin Composition for Tow Prepreg (RX-2)) A resin composition for tow prepreg (RX-2) was obtained in the same manner as in Example 5, except that 4 parts by mass of the polytetramethylene ether compound (D'-1) was added instead of the polytetramethylene ether compound (D-1). A resin molded plate and a tow prepreg (R2) were produced in the same manner as in Example 1, except that the resin composition (RX-2) obtained was used, and each evaluation was performed.

[0092] (Comparative Example 3: Preparation and Evaluation of Resin Composition for Tow Prepreg (RX-3)) A resin composition for tow prepreg (RX-3) was obtained in the same manner as in Example 5, except that 8 parts by mass of the polytetramethylene ether compound (D'-1) was added instead of the polytetramethylene ether compound (D-1). A resin molded plate and a tow prepreg (R3) were produced in the same manner as in Example 1, except that the resin composition (RX-3) obtained was used, and each evaluation was performed.

[0093] (Comparative Example 4: Preparation and Evaluation of Resin Composition for Tow Prepreg (RX-4)) A resin composition for tow prepreg (RX-4) was obtained in the same manner as in Example 5, except that the amount of the first (meth)acrylate monomer (b1-1) added was changed to 40 parts by mass, and that the second (meth)acrylate monomer (b2-1) was not added at all. A resin molded plate and a tow prepreg (R4) were produced in the same manner as in Example 1, except that the obtained resin composition (RX-4) was used, and each evaluation was performed.

[0094] (Comparative Example 5: Preparation and Evaluation of Resin Composition for Tow Prepreg (RX-5)) A resin composition for tow prepreg (RX-5) was obtained in the same manner as in Example 5, except that the first (meth)acrylate monomer (b1-1) was not added at all and the amount of the second (meth)acrylate monomer (b2-1) added was changed to 40 parts by mass. A resin molded plate and a tow prepreg (R5) were produced in the same manner as in Example 1, except that the obtained resin composition (RX-5) was used, and each evaluation was performed.

[0095] (Comparative Example 6: Preparation and Evaluation of Resin Composition for Tow Prepreg (RX-6)) A resin composition for tow prepreg (RX-6) was obtained in the same manner as in Example 5, except that the second (meth)acrylate monomer (b2-1) was not added at all and that cyclohexyl methacrylate (molecular weight 168, weight loss rate when heated at 50°C under normal pressure for 1 hour 11.5%) was further added as the (meth)acrylate monomer (B'-1). A resin molded plate and a tow prepreg (R6) were produced in the same manner as in Example 1, except that the resin composition (RX-6) obtained was used, and each evaluation was performed.

[0096] The evaluation results of the resin compositions for tow prepregs (1) to (16) and (R1) to (R8) obtained above are shown in Tables 1 to 3. In the tables, "ethylenically unsaturated monomer content (mass%)" indicates the total mass of the first (meth)acrylate monomer (b1-1) and the second (meth)acrylate monomer (b2-1) relative to the total mass of the urethane (meth)acrylate resin (A-1), the (meth)acrylate monomer (B) having a molecular weight of 200 or more and 500 or less, and the thermoplastic urethane resin (C-1).

[0097] [Table 1]

[0098] [Table 2]

[0099] [Table 3]

[0100] From Tables 1 to 3, it can be seen that the resin compositions for tow prepregs (X-1) to (X-16) of Examples 1 to 16 can all be used to produce cured resin plates with excellent impact resistance and heat resistance, and therefore it is possible to realize tow prepregs with excellent fracture toughness and heat resistance. It can also be seen that the tow prepregs (1) to (16) obtained from the resin compositions for tow prepregs (X-1) to (X-16) of Examples 1 to 16 have excellent fracture toughness and heat resistance.

[0101] In contrast, the resin compositions for tow prepregs (RX-1) to (RX-3) of Comparative Examples 1 to 3 cannot produce cured resin plates with excellent impact resistance, and the resin composition for tow prepregs (RX-4) of Comparative Example 4 cannot produce cured resin plates with excellent heat resistance. Also, it is found that the tow prepregs (R5) to (R6) obtained from the resin compositions for tow prepregs (RX-5) to (RX-6) of Comparative Examples 5 and 6 have low impregnation and unwinding properties.

Claims

1. The composition contains a urethane (meth)acrylate resin (A), a (meth)acrylate monomer (B) having a molecular weight of 200 or more and 500 or less, a thermoplastic polyurethane resin (C), a polytetramethylene ether compound (D) having an acrylic group or a methacrylic group at a terminal, and a polymerization initiator (E), the urethane (meth)acrylate (A) is a reaction product of a polyisocyanate (a1), a polyol having an aromatic skeleton (a2), and a hydroxyalkyl (meth)acrylate (a3); the (meth)acrylate monomer (B) has a weight loss rate (%) of less than 3 when heated at normal pressure and 50° C. for 1 hour, and contains a first (meth)acrylate monomer (b1) having an aromatic skeleton and a second (meth)acrylate monomer (b2) having an alicyclic skeleton, The polytetramethylene ether compound (D) has a polyether segment molecular weight of 1,000 or more and 3,000 or less.

2. 2. The resin composition for tow prepregs according to claim 1, wherein a total content of the first (meth)acrylate monomer (b1) and the second (meth)acrylate monomer (b2) is 30 to 60 mass % based on a total mass of the urethane (meth)acrylate resin (A), the (meth)acrylate monomer (B), and the thermoplastic polyurethane resin (C).

3. 3. The resin composition for tow prepregs according to claim 1 or 2, wherein a content of the polytetramethylene ether compound (D) is 1 to 20 parts by mass per 100 parts by mass of the total of the urethane (meth)acrylate resin (A), the (meth)acrylate monomer (B), and the thermoplastic polyurethane resin (C).

4. 3. The resin composition for a tow prepreg according to claim 1, wherein the polyol (a2) is an oxyalkylene adduct of a bisphenol compound.

5. 3. The resin composition for tow prepregs according to claim 1 or 2, wherein the thermoplastic polyurethane resin (C) is obtained from a resin composition containing polytetramethylene ether glycol as a main raw material.

6. A tow prepreg comprising the resin composition for tow prepregs according to claim 1 or 2 and reinforcing fiber bundles, A tow prepreg, comprising the reinforcing fiber bundles impregnated with the resin composition for a tow prepreg.

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