Resin composition for tow prepreg, and tow prepreg

Abstract

Provided are: a resin composition for tow prepregs, which enables the achievement of a tow prepreg having excellent impregnability, reelability, fracture toughness, and heat resistance; and a tow prepreg. This unsaturated resin composition for prepregs is characterized by containing (A) a urethane (meth) acrylate resin, (B) a (meth) acrylate monomer having a molecular weight of 200-500, (C) a thermoplastic polyurethane resin, (D) a polytetramethylene ether compound having an acryloyl group or a methacryloyl group at a terminal, and (E) a polymerization initiator. The (meth) acrylic acid ester monomer (B) contains a first (meth) acrylic acid ester monomer (b1) having an aromatic skeleton and a second (meth) acrylic acid ester monomer (b2) having an alicyclic skeleton, the weight loss rate (%) of the first (meth) acrylic acid ester monomer (b1) being less than 3 when heated at normal pressure at 50 DEG C for 1 hour, and the molecular weight of the polyether segment of the polytetramethylene ether compound (D) is 1000-3000.

Description

Technical Field

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

[0002] The fiber-reinforced resin composite material formed by impregnating the resin in the reinforcing fibers such as carbon fiber and glass fiber is lightweight and has excellent heat resistance and mechanical strength, so it can be used for various purposes such as automobile components, aerospace components, residential equipment components, and motion components. In the past, as a forming method of fiber-reinforced resin composite materials, it is known to use an intermediate material called prepreg formed by impregnating the reinforcing fibers with a thermosetting resin, and a method of curing and forming by autoclave forming, press forming, filament winding forming, drawing forming, etc. For example, in patent document 1, a prepreg resin composition comprising carbamate (methyl) acrylate, a polymerization initiator and a thermoplastic polyurethane resin is disclosed, and the prepreg formed by impregnating the prepreg resin composition with the reinforcing fibers is pressed and formed, thereby being able to make a molded body with excellent softness, impact resistance and heat resistance.

[0003] On the other hand, high-pressure tanks for storing natural gas, hydrogen, etc. require further excellent durability and impact resistance. As a manufacturing method for the above-mentioned high-pressure tank, for example, Patent Document 2 discloses a manufacturing method using a tow prepreg made by impregnating a resin into a reinforcing fiber bundle (tow) such as carbon fiber and glass fiber. According to Patent Document 2, a lightweight and high-strength high-pressure tank can be manufactured.

[0004] Therefore, as a molding material for producing a high-pressure tank, a tow prepreg disclosed in Patent Document 1, in which a tow is impregnated with a prepreg resin composition, can be considered.

[0005] However, in this case, since the viscosity of the prepreg resin composition disclosed in Patent Document 1 is high, there is a disadvantage that not only the impregnation into the tow is low, but also the unreleasability from the bobbin is low. If the above-mentioned unreleasability is low, the productivity is reduced, and the quality stability of the high-pressure tank is reduced. Therefore, in order to reduce the viscosity, it is considered to add a (meth)acrylate monomer to the above-mentioned prepreg resin composition, but there is a disadvantage that the fracture toughness of the above-mentioned prepreg resin composition is sometimes reduced. In this case, with respect to the high-pressure tank, sufficient durability and impact resistance cannot be ensured. In addition, it is considered to use methyl methacrylate monomer as the above-mentioned (meth)acrylate monomer, but there is a disadvantage that methyl methacrylate volatilizes during the manufacture of the high-pressure tank. Accompanied by the above-mentioned volatilization, the quality stability of the high-pressure tank is reduced or there is a risk of fire.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 6610982

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2022-22548 Summary of the invention

[0010] Problems to be solved by the invention

[0011] The problem to be solved by the present invention is to provide a resin composition for a tow prepreg that can realize a tow prepreg having excellent impregnation, decompression, fracture toughness and heat resistance. In addition, the problem to be solved by the present invention is to provide a tow prepreg having excellent impregnation, decompression, fracture toughness and heat resistance.

[0012] Means for solving problems

[0013] The resin composition for tow prepreg of the present invention is characterized by comprising: 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 acryloyl group or a methacryloyl group at a terminal, and a polymerization initiator (E), wherein the urethane (meth) acrylate resin (A) is a polyisocyanate (a1), a polyol (a2) having an aromatic skeleton, and a (meth) The reaction product of a hydroxyalkyl acrylate (a3), wherein the (meth)acrylate monomer (B) comprises a first (meth)acrylate monomer (b1) having an aromatic skeleton and a weight loss rate (%) of less than 3 when heated at 50°C for 1 hour at normal pressure, 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 for 1 hour at normal pressure, and the molecular weight of the polyether segment of the polytetramethylene ether compound (D) is 1000 or more and 3000 or less.

[0014] The strand prepreg of the present invention is characterized by comprising the above-mentioned strand prepreg resin composition and a reinforcing fiber bundle, wherein the reinforcing fiber bundle is impregnated with the above-mentioned strand prepreg resin composition.

[0015] Effects of the Invention

[0016] According to the present invention, a resin composition for a tow prepreg can be provided that can realize a tow prepreg having excellent impregnation, decompression, fracture toughness and heat resistance. In addition, according to the present invention, a tow prepreg having excellent impregnation, decompression, fracture toughness and heat resistance can be provided. DETAILED DESCRIPTION

[0017] The unsaturated resin composition for prepreg of the present invention is characterized by comprising: 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 acryloyl group or a methacryloyl group at a terminal, and a polymerization initiator (E), wherein the urethane (meth) acrylate resin (A) is a polyisocyanate (a1), a polyol (a2) having an aromatic skeleton, and a (meth) The reaction product of a hydroxyalkyl acrylate (a3), wherein the (meth)acrylate monomer (B) comprises a first (meth)acrylate monomer (b1) having an aromatic skeleton and a weight loss rate (%) of less than 3 when heated at 50°C for 1 hour at normal pressure, 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 for 1 hour at normal pressure, and the molecular weight of the polyether segment of the polytetramethylene ether compound (D) is 1000 or more and 3000 or less.

[0018] The urethane (meth)acrylate resin (A) is a reaction product of a polyisocyanate (a1), a polyol (a2) having an aromatic skeleton, and a hydroxyalkyl (meth)acrylate (a3).

[0019] From the viewpoint of further improving the heat resistance of the molded article, the polyisocyanate (a1) preferably contains a polyisocyanate having an aromatic skeleton or an alicyclic skeleton. These polyisocyanates (a1) may be used alone or in combination of two or more.

[0020] Examples of the polyisocyanate (a1) include 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, carbodiimide-modified 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, urate-modified diphenylmethane diisocyanate, biuret-modified diphenylmethane diisocyanate, urethane-imide-modified diphenylmethane diisocyanate, polyol-modified diphenylmethane diisocyanate having a number average molecular weight of 1,000 or less, such as diethylene glycol and dipropylene glycol, and toluene diisocyanate (TDI). , dimethyl diphenyl diisocyanate, xylylene diisocyanate, 1,5-naphthalene diisocyanate, tetramethylxylylene diisocyanate and other aromatic polyisocyanates; isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, norbornene diisocyanate and other alicyclic polyisocyanates; hexamethylene diisocyanate, hexamethylene diisocyanate urate modified body, biuret modified body, adduct, dimer acid diisocyanate and other aliphatic polyisocyanates, etc.

[0021] Among these, from the aspect of further improving the heat resistance of the molded product, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, carbodiimide modified body of 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, norbornene diisocyanate, xylylene diisocyanate, isophorone diisocyanate (IPDI) are preferred. It should be noted that these polyisocyanates (a1) can be used alone or in combination of two or more.

[0022] The polyol (a2) has an aromatic skeleton. For example, 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 can be cited; 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, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, etc. 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 addition mole number of 2 to 10 moles.

[0023] As the above-mentioned hydroxyalkyl (meth)acrylate (a3), for example, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxy-n-butyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-n-butyl (meth)acrylate, 3-hydroxy-n-butyl (meth)acrylate, etc. can be mentioned. Among these, 2-hydroxyethyl (meth)acrylate is preferred from the balance of strength and physical properties. It should be noted that these hydroxyalkyl (meth)acrylates (a3) ​​can be used alone or in combination of two or more.

[0024] In addition, as required, other polyols other than the above-mentioned polyols (a2) to (a3) ​​may be used as raw materials of the above-mentioned urethane (meth)acrylate resin (A). As other polyols, polyester polyols, acrylic polyols, polyether polyols, polycarbonate polyols, polyalkylene polyols, etc. may be used.

[0025] From the viewpoint of further improving heat resistance and curability, the molar ratio (a2 / a3) of the polyol (a2) to the hydroxyalkyl (meth)acrylate (a3) ​​is preferably 60 / 40 to 20 / 80, more preferably 50 / 50 to 30 / 70.

[0026] From the perspective of the balance between heat resistance and strength properties, the molar ratio (NCO / OH) of the isocyanate group (NCO) of the isocyanate compound as a raw material of the above-mentioned urethane (meth)acrylate resin (A) to the hydroxyl group (OH) of the compound having a hydroxyl group is preferably 0.7 to 1.3, more preferably 0.8 to 1.1, and even more preferably 0.8 to 1.0.

[0027] The resin composition for tow prepreg contains a (meth)acrylate monomer (B) having a molecular weight of 200 to 500. The (meth)acrylate monomer (B) must contain a first (meth)acrylate monomer (b1) having an aromatic skeleton and a weight loss rate (%) of less than 3 when heated at 50°C for 1 hour at normal pressure, 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 for 1 hour at normal pressure.

[0028] The (meth)acrylate monomer (B) has a molecular weight in the above range, so that the dilutability of the urethane (meth)acrylate resin (A) and the thermoplastic polyurethane resin (C) is excellent, and it is suitable for adjusting the viscosity of the resin composition for tow prepreg. In addition, for the (meth)acrylate monomer (B), due to the above molecular weight, the (meth)acrylate monomer (B) itself is not easy to volatilize, thereby preventing the viscosity of the resin composition for tow prepreg from increasing, and obtaining a tow prepreg with excellent impregnation and relaxation properties. In addition, when the obtained tow prepreg is used to manufacture a molded body, the volatilization of the (meth)acrylate monomer (B) from the tow prepreg is suppressed, so the quality stability of the tow prepreg can be ensured, thereby stably manufacturing the molded body, and preventing the volatile components from igniting. 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 prepreg increases. If the molecular weight of the (meth)acrylate monomer (B) exceeds 500, the viscosity of the resin composition for tow prepreg becomes high. From the viewpoint of heat resistance, the (meth)acrylate monomer (B) is more preferably a methacrylate monomer. In addition, considering 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.

[0029] The (meth)acrylate monomer (B) contains both a first (meth)acrylate monomer (b1) and a second (meth)acrylate monomer (b2) having a weight reduction rate (%) of less than 3 when heated at 50°C for 1 hour under normal pressure. The first (meth)acrylate monomer (b1) and the second (meth)acrylate monomer (b2) satisfy the above molecular weight range, and the above weight reduction rate is less than 3, and the volatility is low, so that the viscosity of the resin composition for tow prepreg can be prevented from increasing. The (meth)acrylate monomer having a weight reduction rate exceeding 3 volatilizes, causing the viscosity of the resin composition for tow prepreg to increase, so it is not preferred. However, as long as it is within the range that does not cause the viscosity of the resin composition for tow prepreg to increase, the (meth)acrylate monomer having a weight reduction rate exceeding 3 may also be added.

[0030] The above-mentioned weight reduction rate (%) can be measured, for example, as follows. 2.0 to 2.1 g of (meth)acrylate monomer (B) at room temperature is weighed into a shallow bottom plate made of tinplate with an inner diameter of about 64 mm, and after standing for 1 minute, the shallow bottom plate is placed on a hot plate with a surface temperature of 50°C at normal pressure for 1 hour. After 1 hour, the shallow bottom plate is recovered, and after 10 to 20 seconds at room temperature, the weight is measured to 4 decimal places using a precision balance, and the heating reduction (%) is calculated to the first decimal place. The number of samples N is set to 2 or more, and the average value is taken.

[0031] The (meth)acrylate monomer (B) contains both the first (meth)acrylate monomer (b1) having an aromatic skeleton and the second (meth)acrylate (b2) having an alicyclic skeleton. Since the first (meth)acrylate monomer (b1) has an aromatic skeleton, the dilution effect of the urethane (meth)acrylate resin (A) is excellent, which helps to reduce the viscosity of the resin composition for tow prepreg. The second (meth)acrylate monomer (b2) has an alicyclic skeleton. The alicyclic skeleton is a bulky structure compared to the aromatic skeleton, so compared with the first (meth)acrylate monomer (b1), the dilution effect is poor, but the effect of improving heat resistance is excellent. It is believed that by using the first (meth)acrylate monomer (b1) and the second (meth)acrylate monomer (b2) in combination, a resin composition for tow prepreg with excellent impregnation, relaxation and heat resistance can be obtained. In consideration of the balance between viscosity and heat resistance, the content ratio (mass ratio) of the first (meth)acrylate monomer (b1) to the second (meth)acrylate monomer (b2) is preferably in the range of 20:80 to 60:40.

[0032] 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 a tow prepreg having excellent heat resistance cannot be achieved. 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 a tow prepreg having excellent impregnation properties and unwinding properties cannot be achieved.

[0033] Examples of the first (meth)acrylate monomer (b1) include phenoxyethyl methacrylate, 2-methylphenoxyethyl methacrylate, dimethacrylate of ethylene oxide adduct of bisphenol A, dimethacrylate of ethylene oxide adduct of bisphenol F, and 9,9-bis[4-(2-methacryloyloxyethoxy)phenyl]fluorene, and phenoxyethyl methacrylate is preferred. Examples of the second (meth)acrylate monomer (b2) include tricyclo[5.2.1.0(2,6)]dec-8-yl(meth)acrylate (commonly known as "dicyclopentyl(meth)acrylate"), bornyl methacrylate, isobornyl methacrylate, adamantyl(meth)acrylate, 4-tert-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. Preferred are tricyclo[5.2.1.0(2,6)]dec-8-yl(meth)acrylate (commonly known as "dicyclopentyl(meth)acrylate") and isobornyl methacrylate.

[0034] In addition, from the perspective of further improving the balance between resin impregnation, productivity, and quality of molded products when producing tow prepregs, the total content of the first (meth)acrylate monomer (b1) and the second (meth)acrylate monomer (b2) in the resin composition for tow prepreg is preferably 30 to 60% by mass relative to the total mass of the urethane (meth)acrylate resin (A), the (meth)acrylate monomer (B), and the thermoplastic polyurethane resin (C), and is more preferably 35 to 55% by mass, and even more preferably 35 to 50% by mass from the perspective of the balance between the resin viscosity and the fracture toughness during impregnation.

[0035] As the above-mentioned thermoplastic polyurethane resin (C), a thermoplastic polyurethane with polyalkylene ether polyol as the main raw material is more preferred. These thermoplastic polyurethane resins can be used alone or in combination of two or more. From the perspective of obtaining a molded product with higher strength and high toughness, a thermoplastic polyurethane resin with polytetramethylene ether glycol as the main component is more preferred. The molecular weight of the thermoplastic polyurethane resin (C) is preferably 10,000 to 100,000 on a weight average basis.

[0036] The amount of the thermoplastic polyurethane resin (C) added is preferably in the range of 2 to 10 parts by mass relative to 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), from the perspective of the balance between fracture toughness and liquid stability of the resin solution.

[0037] The resin composition for tow prepreg contains a polytetramethylene ether compound (D) having an acryloyl group or a methacryloyl group at a terminal, wherein the molecular weight of the polyether segment of the polytetramethylene ether compound (D) is 1000 to 3000. The molecular weight is more preferably 1500 to 2500.

[0038] Here, 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.

[0039] Molecular weight of polyether segment = (hydroxyl equivalent of polytetramethylene ether glycol) × 2 Formula (1)

[0040] By using the polytetramethylene ether compound (D) having a molecular weight within the above range, a tow prepreg resin composition having excellent fracture toughness and heat resistance can be obtained. When the molecular weight of the above segment is less than 1000, the heat resistance cannot be improved, and when the molecular weight of the above segment exceeds 3000, the fracture toughness cannot be improved.

[0041] Examples of the polytetramethylene ether compound (D) include di(meth)acrylates obtained by reacting polytetramethylene ether glycol with (meth)acrylic acid, (meth)acrylate esters, or (meth)acrylic anhydride and purifying the reacted compounds; urethane (meth)acrylates obtained by reacting polytetramethylene ether glycol with a diisocyanate compound and 2-hydroxyethyl (meth)acrylate; and di(meth)acrylates obtained by reacting polytetramethylene ether glycol with 2-isocyanatoethyl (meth)acrylate. Among these, polytetramethylene ether glycol di(meth)acrylate is preferred from the perspective of obtaining a cured resin having a higher fracture toughness and being able to 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.

[0042] 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, more preferably 3 to 18 parts by mass, relative to 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).

[0043] As the above-mentioned polymerization initiator (E), there is no particular limitation, and organic peroxides are preferred, for example, diacyl peroxide compounds, peroxyester compounds, hydroperoxide compounds, ketone peroxide compounds, alkyl perester compounds, percarbonate compounds, peroxyketals, etc. can be mentioned, and they can be appropriately selected according to the molding conditions. It should be noted that these polymerization initiators (E) can be used alone or in combination of two or more. In addition, photopolymerization initiators can also be used in combination.

[0044] In addition, as the polymerization initiator (E), for the purpose of shortening the molding time, it is preferred to use a polymerization initiator having a temperature of 60°C or higher and 110°C or lower for obtaining a half-life of 10 hours. If it is 70°C or higher and 105°C or lower, the life of the prepreg at room temperature is long, and curing can be performed in a short time (within 5 minutes) by heating, so it is preferred that the curing property and molding property are further improved by using it in the prepreg of the present invention. Examples of such polymerization initiators include 1,6-bis(tert-butylperoxycarbonyloxy)hexane, 1,1-bis(tert-butylperoxy)cyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 1,1-bis(tert-hexylperoxy)cyclohexane, tert-butyl peroxydiethylacetate, tert-butyl peroxyisopropylcarbonate, tert-butyl peroxy-2-ethylhexylcarbonate, tert-amyl peroxyisopropylcarbonate, tert-amyl peroxy-2-ethylhexylcarbonate, tert-hexyl peroxyisopropylcarbonate, di-tert-butyl peroxyhexahydroterephthalate, tert-amyl peroxytrimethylhexanoate, tert-amyl peroxyisononanoate, tert-hexyl peroxy-2-ethylhexanoate, and n-butyl 4,4-di(tert-butylperoxy)valerate. An optimal organic peroxide is selected and used according to molding conditions.

[0045] The amount of the polymerization initiator (E) added is preferably in the range of 0.5 to 4 parts by mass relative to 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), from the viewpoint of excellent curing characteristics and storage stability.

[0046] The heating temperature when impregnating the strands with the strand prepreg resin composition depends on the capacity of the strand prepreg manufacturing equipment, and is preferably about 30 to 60°C. From the viewpoint of both preventing abnormal decomposition of peroxides and reducing viscosity, it is more preferably around 40 to 50°C. In addition, from the viewpoint of productivity when manufacturing strand prepregs, the viscosity of the strand prepreg resin composition is preferably in the range of 0.1 to 5 Pa·S in the temperature range of 30 to 60°C. The resin composition is finely adjusted so that the viscosity of the strand prepreg resin composition is within the above range.

[0047] As components of the resin composition for the tow prepreg of the present invention, components other than the above-mentioned can be used, for example, it can contain thermosetting resins, thermoplastic resins, inhibitors, curing accelerators, fillers, low shrinkage agents, release agents, thickeners, thickeners, pigments, antioxidants, plasticizers, flame retardants, antibacterial agents, ultraviolet stabilizers, reinforcing materials, photopolymerization initiators, etc.

[0048] Examples of the thermosetting resin include vinyl ester resins, unsaturated polyester resins, epoxy resins, bismaleimide resins, etc. These thermosetting resins may be used alone or in combination of two or more.

[0049] As the above-mentioned thermoplastic resin, for example, 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 resins modified by copolymerization, etc. can be cited. Among these, polyamide resin and polyurethane resin are preferred from the aspect of high improvement effect of brittleness. In addition, these thermoplastic resins can be used alone or in combination of two or more. In addition, the thermoplastic resin can be added in the form of particles and used, or it can be melt-mixed and used. When using a thermoplastic resin in the form of particles, from the viewpoint of dispersibility in the fiber, the particle system is preferably 30 μm or less, and more preferably 5 to 20 μm.

[0050] Examples of the polymerization inhibitor include hydroquinone, trimethylhydroquinone, p-tert-butylcatechol, tert-butylhydroquinone, toluhydroquinone, p-benzoquinone, naphthoquinone, hydroquinone monomethyl ether, phenothiazine, copper naphthenate, copper chloride, etc. These polymerization inhibitors may be used alone or in combination of two or more.

[0051] The filler includes 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.

[0052] Examples of the inorganic compound include calcium carbonate, magnesium carbonate, barium sulfate, mica, talc, kaolin, clay, diatomaceous earth, asbestos, barite, barium oxide, silicon dioxide, silica sand, dolomite, limestone, gypsum, aluminum powder, hollow spheres, aluminum oxide, glass powder, aluminum hydroxide, calcite, zirconium oxide, antimony trioxide, titanium oxide, molybdenum dioxide, and iron powder.

[0053] As the above-mentioned organic compound, there are natural polysaccharide powders such as cellulose and chitin, synthetic resin powders, etc., and as synthetic resin powders, organic powders composed of hard resins, soft rubbers, elastomers or polymers (copolymers), etc., particles with multilayer structures such as core-shell types can be used. Specifically, acrylic particles, polyamide particles, particles formed by butadiene rubber and / or acrylic rubber, urethane rubber, silicone rubber, etc., polyimide resin powders, fluororesin powders, phenolic resin powders, etc. can be cited. These fillers can be used alone or in combination of two or more.

[0054] Examples of the release agent include zinc stearate, calcium stearate, paraffin wax, polyethylene wax, carnauba wax, etc. Preferably, paraffin wax, polyethylene wax, carnauba wax, etc. These release agents may be used alone or in combination of two or more.

[0055] Examples of the thickener include polyisocyanate compounds and acrylic resin microparticles, and the thickener can be appropriately selected according to the handling properties of the tow prepreg of the present invention. These thickeners may be used alone or in combination of two or more.

[0056] The photopolymerization initiator is a polymerization initiator that generates free radicals by light irradiation, and any known photopolymerization initiator can be used without particular limitation. As the photopolymerization initiator, alkylphenone-based free radical initiators, benzophenone-based free radical initiators, benzoin-based free radical initiators, acylphosphine oxide-based free radical initiators, etc. are preferred from the perspective of easy availability.

[0057] The resin composition for tow prepreg is prepared by mixing a urethane (meth) acrylate resin (A), the above-mentioned (meth) acrylate monomer (B), a thermoplastic polyurethane resin (C), a polytetramethylene ether compound (D) having an acryloyl group or a methacryloyl group at the end, and a polymerization initiator (E). For example, when manufacturing the urethane (meth) acrylate resin (A), a method in which a polyol (a2) having an aromatic skeleton is pre-mixed with a thermoplastic polyurethane resin (C) and a hydroxyalkyl (meth) acrylate (a3), and then a polyisocyanate (a1) is added and reacted to obtain a mixture of the urethane (meth) acrylate resin (A) and the thermoplastic polyurethane resin (C) is excellent in mass productivity and is desirable.

[0058] The strand prepreg resin composition is impregnated into a reinforcing fiber bundle and used as a strand prepreg. That is, the strand prepreg of the present invention is characterized by containing the strand prepreg resin composition and a reinforcing fiber bundle, and the strand prepreg resin composition is impregnated into the reinforcing fiber bundle.

[0059] As the fiber of the above-mentioned reinforcing fiber bundle, organic fibers such as carbon fiber, glass fiber, silicon carbide fiber, aluminum oxide fiber, boron fiber, metal fiber, aramid fiber, vinylon fiber, Teflon fiber, etc. can be enumerated. From the aspect of the molded product that can obtain higher strength and high elasticity, preferably carbon fiber or glass fiber, aramid fiber, in order to manufacture the high-pressure tank for storing natural gas, hydrogen, etc., more preferably carbon fiber. These reinforcing fibers can be used alone, and two or more kinds can also be used in combination.

[0060] As the carbon fiber, various carbon fibers such as polyacrylonitrile-based, pitch-based, and rayon-based carbon fibers can be used. Among these, polyacrylonitrile-based carbon fibers are preferred because high-strength carbon fibers can be easily obtained.

[0061] The shape of the reinforcing fibers is not particularly limited, and examples thereof include reinforcing fiber bundles in which reinforcing fiber filaments are bundled, unidirectional materials in which reinforcing fiber bundles are paralleled in one direction, and woven fabric-like reinforcing fibers. In the case of bundle prepregs, high mechanical properties can be obtained by using reinforcing fiber bundles and stacking them, which is preferred.

[0062] The content of the reinforcing fiber bundle 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, from the viewpoint of further improving the mechanical strength of the obtained molded article.

[0063] The tow prepreg of the present invention can be produced by various known methods, but a production method that does not use a diluting solvent, etc. is desirable. Specifically, the following production method is desirable: the unsaturated resin composition of the present invention is heated to reduce the viscosity, and is brought into contact with a reinforcing fiber bundle paralleled in one direction using a resin bath or a coating machine, and then impregnated with resin while being pressed and bonded using a rotating roller, and then wound on a bobbin, etc.

[0064] As a method for obtaining a molded product from the obtained tow prepreg, for example, the tow prepreg wound on a bobbin is unwound, and after being wound on a resin or metal liner, a shrink film is wound on the surface, and then heated and cured by an oven, etc., thereby a molded product such as a gas tank can be made. In addition, after the tow prepreg is wound on a metal rod, a tube, etc., the same treatment is performed to heat and cure it, thereby making a fiber-reinforced metal component. A spindle, a rotating roller, a power transmission shaft, etc. can be cited. The combination and composition can be appropriately selected according to the product. The tow prepreg using the resin composition for tow prepreg of the present invention has excellent unwinding properties when unwinding from a bobbin, etc., so the productivity is high, and the quality stability of the molded product can be ensured. In addition, the tow prepreg using the resin composition for tow prepreg of the present invention does not have the worry of volatilization of the (meth) acrylate monomer (B) contained in the above-mentioned resin composition, so the quality stability of the tow prepreg can be ensured, thereby the molded body can be stably manufactured, and the volatile components can be prevented from igniting.

[0065] The molded article obtained from the prepreg of the present invention has excellent fracture toughness and heat resistance, and therefore can be suitably used in automobile parts, railway vehicle parts, aerospace 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, etc.

[0066] [Example]

[0067] Hereinafter, the present invention will be described in more detail with reference to specific examples.

[0068] (Synthesis Example 1: Production of Thermoplastic Polyurethane Resin (C-1))

[0069] 710 g of PTMG1000 (Mitsubishi Chemical Co., Ltd., 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 pot, cast onto a stainless steel plate, 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.

[0070] (Synthesis Example 2: Production of a polytetramethylene ether compound (D-1) having an acryloyl group or a methacryloyl group at a terminal)

[0071] In a 0.5L flask equipped with a thermometer, nitrogen and air inlet tubes, and a stirrer, 100g of PTMG1000 (Mitsubishi Chemical Co., Ltd., polytetramethylene ether glycol, hydroxyl equivalent: 505g / eq), 33g of methacrylic anhydride, 0.03g of tert-butyl hydroquinone, and 0.5g of dimethylaminopyridine were added and mixed, and then heated to 100°C under a gas flow of nitrogen and air mixed in a ratio of 1:1. After being kept at 100°C for 4 hours, the mixture was cooled to 80°C, and 200g of toluene was added to form a uniform solution, and then 100g of a 10% by weight sodium bicarbonate aqueous solution was slowly added and stirred for 1 hour. All the contents were transferred to a separatory funnel, and the aqueous phase was separated from the organic phase, and the aqueous phase was removed. 100g of a 10% by weight sodium bicarbonate aqueous solution was slowly added to the obtained organic phase again, and the mixture was shaken and stirred. The aqueous phase was separated from the organic phase, and the residual organic phase from which the aqueous phase was removed was transferred again to a 0.5 L flask, and the solvent was removed under reduced pressure at 95° C. for 2 hours, and the pressure was restored to normal, and the contents were taken out. The obtained contents contained a polytetramethylene ether compound (D-1) having a methacryloyl group at the end. The molecular weight of the above compound (D-1) as a polyether segment was calculated based on the hydroxyl equivalent of the raw material and using formula (1), and was 1010. The hydroxyl value of the above compound (D-1) was 2 mgKOH / g.

[0072] (Synthesis Example 3: Production of a polytetramethylene ether compound (D-2) having an acryloyl group or a methacryloyl group at a terminal)

[0073] 100 g of PTMG2000 (Mitsubishi Chemical Co., Ltd., polytetramethylene ether glycol, hydroxyl equivalent: 975 g / eq), 17 g of methacrylic anhydride, 0.03 g of tert-butyl hydroquinone and 0.4 g of dimethylaminopyridine were added to the above 0.5 L flask and mixed, and then heated to 100° C. under a gas flow of nitrogen and air mixed in a ratio of 1:1. After being kept at 100° C. for 4 hours, the mixture was cooled to 80° C., 200 g of toluene was added to form a uniform solution, and 100 g of a 10 wt % sodium bicarbonate aqueous solution was slowly added and stirred for 1 hour. All the contents were transferred to a separatory funnel, the aqueous phase was separated from the organic phase, and the aqueous phase was removed. The remaining organic phase was transferred to a 0.5 L flask again, and a decompression desolventizing treatment was performed at 95° C. for 2 hours, and the pressure was restored to normal pressure, and the contents were taken out. The obtained contents contained a polytetramethylene ether compound (D-2) having a methacryloyl group at the end. The molecular weight of the diol as a chain segment of the compound (D-2) was 1950. The hydroxyl value of the compound (D-2) was 1 mgKOH / g.

[0074] (Synthesis Example 4: Production of a polytetramethylene ether compound (D-3) having an acryloyl group or a methacryloyl group at a terminal)

[0075] 100 g of PTMG3000 (manufactured by Mitsubishi Chemical Co., Ltd., polytetramethylene ether glycol, hydroxyl equivalent: 1435 g / eq), 12 g of methacrylic anhydride, 0.03 g of tert-butyl hydroquinone and 0.4 g of dimethylaminopyridine were added to the above-mentioned 0.5 L flask and mixed, and then heated to 100° C. under the flow of a gas mixture of nitrogen and air in a ratio of 1:1. After being kept at 100° C. for 4 hours, the mixture was cooled to 80° C., 200 g of toluene was added to form a uniform solution, and 100 g of a 7 wt % aqueous sodium bicarbonate solution was slowly added and stirred for 1 hour. All the contents were transferred to a separatory funnel, the aqueous phase and the organic phase were separated, and the aqueous phase was removed. The remaining organic phase was transferred to a 0.5 L flask again, and a decompression desolventizing treatment was performed at 95° C. for 2 hours, and the pressure was restored to normal pressure, and the contents were taken out. The obtained contents contained a polytetramethylene ether compound (D-3) having a methacryloyl group at the end. The molecular weight of the diol as a chain segment of the compound (D-3) was 2870. The hydroxyl value of the compound (D-3) was 0 mgKOH / g.

[0076] (Synthesis Example 5: Production of a polytetramethylene ether compound (D-4) having an acryloyl group or a methacryloyl group at a terminal)

[0077] 100 g of PTMG20000 (Mitsubishi Chemical Co., Ltd., polytetramethylene ether glycol, hydroxyl equivalent: 975 g / eq), 23 g of isophorone diisocyanate, 0.03 g of tert-butyl hydroquinone and 0.1 g of 1,4-diazabicyclo[2.2.2]octane were added to the above 0.5 L flask and mixed, and then heated to 60° C. under the flow of a gas mixture of nitrogen and air in a ratio of 1:1. After maintaining at 60° C. for 1 hour, 13.5 g of hydroxyethyl methacrylate was added, and the temperature was raised to 80° C. over 30 minutes. After maintaining at 80° C. for 4 hours, the mixture was cooled to 60° C. and the contents were taken out. The obtained contents contained a polytetramethylene ether compound (D-4) having a methacryloyl group at the end. The molecular weight of the diol as a chain segment of the above compound (D-4) was 1950. The hydroxyl value of the above compound (D-4) was 0 mgKOH / g.

[0078] (Synthesis Example 6: Production of a polytetramethylene ether compound (D'-1) having an acryloyl group or a methacryloyl group at a terminal)

[0079] 100 g of PTMG4000 (Mitsubishi Chemical Co., Ltd., polytetramethylene ether glycol, hydroxyl equivalent: 1915 g / eq), 9 g of methacrylic anhydride, 0.03 g of tert-butyl hydroquinone and 0.4 g of dimethylaminopyridine were added to the above 0.5 L flask and mixed, and then heated to 100° C. under a gas flow of nitrogen and air mixed in a ratio of 1:1. After being kept at 100° C. for 4 hours, the mixture was cooled to 80° C., 200 g of toluene was added to form a uniform solution, and 100 g of a 3 wt % sodium bicarbonate aqueous solution was slowly added and stirred for 1 hour. All the contents were transferred to a separatory funnel, the aqueous phase and the organic phase were separated, and the aqueous phase was removed. The remaining organic phase was transferred to a 0.5 L flask again, and a decompression desolventizing treatment was performed at 95° C. for 2 hours, and the pressure was restored to normal pressure, and the contents were taken out.

[0080] The obtained content contained a polytetramethylene ether compound (D'-1) having a methacryloyl group at the terminal. The molecular weight of the diol as a chain segment of the compound (D'-1) was 3830. The hydroxyl value of the compound (D'-1) was 0 mgKOH / g.

[0081] (Synthesis Example 7: Production of a Resin Mixture (AC-1) of a Urethane (Meth) Acrylate Resin (A-1) and a Thermoplastic Urethane Resin (C-1))

[0082] In a 5 L flask equipped with a thermometer, nitrogen and air inlet tubes, and a stirrer, 423 g of NEWPOL BPE-20 (manufactured by Sanyo Chemical Industry Co., Ltd., EO adduct of bisphenol A, hydroxyl equivalent: 161 g / eq) and 534 g of NEWPOL BPE-40 (manufactured by Sanyo Chemical Industry Co., Ltd., EO adduct of bisphenol A, hydroxyl equivalent: 203 g / eq) were added, and uniformly mixed at 100°C. After heating to 140°C, 379 g of the above-mentioned thermoplastic resin (C-1) was added in three portions, and stirred and mixed for 6 hours. After confirming uniform dissolution, the mixture was cooled to 120°C, 1025 g of hydroxyethyl methacrylate and 0.9 g of tert-butyl hydroquinone were added, and after stirring at 90°C for 1 hour, the mixture was cooled to 40°C. Next, 492 g of 4,4'-diphenylmethane diisocyanate was added in two portions, and after one hour, 984 g of 2,4'-diphenylmethane diisocyanate was added in four portions, and the temperature was raised to 80°C while paying attention to the heat generation. After 4 hours at 80°C, the contents were taken out from the reaction vessel. Through the above, a resin mixture (AC-1) of a urethane (meth) acrylate resin (A-1) and a thermoplastic urethane resin (C-1) was obtained. The above resin mixture (AC-1) contains 90.2 parts by mass of the above urethane (meth) acrylate resin (A-1) and 9.8 parts by mass of the above thermoplastic urethane resin (C-1) in 100 parts by mass.

[0083] (Example 1: Preparation and evaluation of resin composition for tow prepreg (X-1))

[0084] 15 parts by mass of NK ESTER PEM-100 (manufactured by Shin-Nakamura Chemical Co., Ltd., phenoxyethyl methacrylate, molecular weight 206, weight loss rate when heated at 50°C at normal pressure for 1 hour: 0.7%) as the first (meth)acrylate monomer (b1-1) having an aromatic skeleton, 25 parts by mass of FA-513M (manufactured by Resonac Co., Ltd., dicyclopentyl methacrylate, molecular weight 220, purity 98.3%, weight loss rate when heated at 50°C at normal pressure for 1 hour: 1.7%) as the second (meth)acrylate monomer (b2-1) having an alicyclic skeleton, 60 parts by mass of the above-mentioned resin mixture (AC-1), 4 parts by mass of the above-mentioned polytetramethylene ether compound (D-1), 0.02 parts by mass of p-benzoquinone, and a polymerization initiator (E-1) ("Trigonox 122-C80", and 1.1 parts by mass of an organic peroxide) were mixed to obtain a resin composition (X-1) for a tow prepreg. It should be noted that the first (meth)acrylate monomer (b1-1) and the second (meth)acrylate monomer (b2-1) are both equivalent to a (meth)acrylate monomer (B) having a molecular weight of 200 or more and 500 or less.

[0085] 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% by mass relative to 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 relative to 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.

[0086] [Evaluation of Impact Resistance of Cured Resin Plate]

[0087] The obtained resin composition (X-1) was cast between glass plates with a gap of 6 mm. The temperature was raised from room temperature to 150°C in 1.5 hours using a heating furnace. After being kept at 150°C for 1 hour, it was cooled to 80°C in 30 minutes and then allowed to cool at room temperature to obtain a cured product of the prepreg resin with a thickness of 6 mm. The cured product was cut into pieces with a width of 12.7 mm and a length of 55 mm using a diamond cutter to introduce a precrack. Then, according to ASTM D5045-99, the number of samples was set to n = 10, and the fracture toughness value (K IC ) and evaluated according to the following criteria.

[0088] ○:1.8(MPa·m 0.5 )above

[0089] △: 1.5 or more and less than 1.8 (MPa·m 0.5 )

[0090] ×: less than 1.5 (MPa·m 0.5 )

[0091] [Evaluation of Heat Resistance of Cured Resin Plate]

[0092] The resin composition (X-1) was cast between glass plates with a gap of 4 mm, and the temperature was raised from room temperature to 150°C in 1.5 hours using a heating furnace. After being kept at 150°C for 1 hour, it was cooled to 80°C in 30 minutes and allowed to cool at room temperature to obtain a cured product of the prepreg resin with a thickness of 4 mm. The cured product was cut into pieces with a width of 10 mm and a length of 45 mm using a diamond cutter, and the dynamic viscoelasticity was measured using the "RSA-G2" manufactured by TA Instruments at a measurement frequency of 1 Hz, a heating rate of 5°C / min, and a 3-point bending mode in a temperature range of 10 to 200°C. In the obtained storage modulus E', the intersection of the approximate straight line of the glass region and the tangent of the transition region was taken as the glass transition temperature (Tg), and the heat resistance was evaluated according to the following criteria.

[0093] ○:115℃ or above

[0094] △: 105℃ or above and less than 115℃

[0095] ×: less than 105℃

[0096] [Production of tow prepreg]

[0097] A tow prepreg was prepared in the following manner using the obtained resin composition (X-1) and high-strength carbon fiber T700SC-12K (manufactured by Toray Industries, Inc.) as a reinforcing fiber bundle.

[0098] 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, a resin composition (X-1) adjusted to 50°C was applied to one side of a unidirectional reinforcing fiber bundle so that the content of the resin composition (X-1) in the tow prepreg became 24% by mass, and then the tow prepreg was passed through a nip roll to impregnate the interior of the reinforcing fiber bundle with the resin composition (X-1), and the tow prepreg (1) was obtained by running at 20 m / min for 1 hour.

[0099] The obtained tow prepreg (1) was packaged with an oxygen barrier film, placed in a bag of the oxygen barrier film, purged with nitrogen, sealed, and left to stand at room temperature.

[0100] [Evaluation of Resin Impregnation of Tow Prepreg]

[0101] The obtained tow prepreg (1) was taken out 7 days after the production and evaluated by visual observation.

[0102] ○: Both sides of the reinforcing fiber bundle are uniformly impregnated.

[0103] Δ: A small amount of unimpregnated fibers were observed on both sides of the reinforcing fiber bundle.

[0104] ×: Both surfaces of the reinforcing fiber bundle are not homogeneous, and unimpregnated fibers exist.

[0105] [Evaluation of the Relaxation of Tow Prepreg]

[0106] The tow prepreg (1) obtained above was taken out 7 days after the production, fixed to a creel, and the leading end of the tow prepreg was wound around an empty bobbin and unwound at a speed of 30 m / min. The unwinding state at this time was evaluated.

[0107] ○: The tow prepreg can be pulled out to the end, and the rotation speed of the bobbin is stable from the beginning to the end.

[0108] △: The tow prepreg can be pulled out to the end, but the rotation speed of the bobbin is unstable.

[0109] ×: The tow prepreg adheres strongly to the bobbin, and the tow prepreg cannot be stably unwound.

[0110] (Example 2: Preparation and evaluation of resin composition for tow prepreg (X-2))

[0111] The same procedure as in Example 1 was followed except that the amount of the polytetramethylene ether compound (D-1) added was changed to 8 parts by mass to obtain a resin composition (X-2) for a tow prepreg. A resin molded plate and a tow prepreg (2) were prepared in the same manner as in Example 1 except that the obtained resin composition (X-2) was used, and various evaluations were performed.

[0112] (Example 3: Preparation and evaluation of resin composition for tow prepreg (X-3))

[0113] The same procedure as in Example 1 was followed except that the amount of the polytetramethylene ether compound (D-1) added was changed to 14 parts by mass to obtain a resin composition (X-3) for a tow prepreg. A resin molded plate and a tow prepreg (3) were prepared in the same manner as in Example 1 except that the obtained resin composition (X-3) was used, and various evaluations were performed.

[0114] (Example 4: Preparation and evaluation of resin composition for tow prepreg (X-4))

[0115] 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 prepared in the same manner as in Example 1 except that the obtained resin composition (X-4) was used, and various evaluations were performed.

[0116] (Example 5: Preparation and evaluation of resin composition for tow prepreg (X-5))

[0117] 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 prepared in the same manner as in Example 1 except that the obtained resin composition (X-5) was used, and various evaluations were performed.

[0118] (Example 6: Preparation and evaluation of resin composition for tow prepreg (X-6))

[0119] 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 prepared in the same manner as in Example 1 except that the obtained resin composition (X-6) was used, and various evaluations were performed.

[0120] (Example 7: Preparation and evaluation of resin composition for tow prepreg (X-7))

[0121] 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 prepared in the same manner as in Example 1 except that the obtained resin composition (X-7) was used, and various evaluations were performed.

[0122] (Example 8: Preparation and evaluation of resin composition for tow prepreg (X-8))

[0123] 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 prepared in the same manner as in Example 1 except that the obtained resin composition (X-8) was used, and various evaluations were performed.

[0124] (Example 9: Preparation and evaluation of resin composition for tow prepreg (X-9))

[0125] The addition amount of the first (meth)acrylate monomer (b1-1) was changed to 10 parts by mass, and the addition amount of the second (meth)acrylate monomer (b2-1) was changed to 30 parts by mass. The same operation as in Example 5 was performed except that the above was changed to obtain a resin composition (X-9) for tow prepreg. Using the obtained resin composition (X-9), the same operation as in Example 1 was performed except that the above was changed to obtain a resin molded plate and a tow prepreg (9), and each evaluation was performed.

[0126] (Example 10: Preparation and evaluation of resin composition for tow prepreg (X-10))

[0127] The addition amount of the first (meth) acrylate monomer (b1-1) was changed to 20 parts by mass, and the addition amount of the second (meth) acrylate monomer (b2-1) was changed to 20 parts by mass. The same operation as in Example 5 was performed except that the above was changed to 20 parts by mass, to obtain a resin composition for tow prepreg (X-10). Using the obtained resin composition (X-10), the same operation as in Example 1 was performed except that the above was changed to 20 parts by mass, to produce a resin molded plate and a tow prepreg (10), and each evaluation was performed.

[0128] (Example 11: Preparation and evaluation of resin composition for tow prepreg (X-11))

[0129] The addition amount of the first (meth)acrylate monomer (b1-1) was changed to 20 parts by mass, and 20 parts by mass of acrylate IBX (manufactured by Mitsubishi Chemical Co., Ltd., isobornyl methacrylate, molecular weight 222, weight loss rate of 1.5% when heated at 50°C for 1 hour under normal pressure) was added as the second (meth)acrylate monomer (b2-2) instead of the second (meth)acrylate monomer (b2-1). The same operation as in Example 5 was performed except for the above, to obtain a resin composition (X-11) for tow prepreg. Using the obtained resin composition (X-11), the same operation as in Example 1 was performed except for the above, to produce a resin molded plate and a tow prepreg (11), and various evaluations were performed.

[0130] (Example 12: Preparation and evaluation of resin composition for tow prepreg (X-12))

[0131] The addition amount of the first (meth) acrylate monomer (b1-1) 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). The same operation as in Example 5 was performed except for the above, to obtain a resin composition (X-12) for tow prepreg. Using the obtained resin composition (X-12), the same operation as in Example 1 was performed except for this, to produce a resin molded plate and a tow prepreg (12), and various evaluations were performed.

[0132] (Example 13: Preparation and evaluation of resin composition for tow prepreg (X-13))

[0133] The addition amount of the first (meth) acrylate monomer (b1-1) was changed to 20 parts by mass, the addition amount of the second (meth) acrylate monomer (b2-1) was changed to 10 parts by mass, and 10 parts by mass of the second (meth) acrylate monomer (b2-2) was further added. The same operation as in Example 5 was performed except for the above, to obtain a resin composition (X-13) for tow prepreg. Using the obtained resin composition (X-13), the same operation as in Example 1 was performed except for this, to produce a resin molded plate and a tow prepreg (13), and various evaluations were performed.

[0134] (Example 14: Preparation and evaluation of resin composition for tow prepreg (X-14))

[0135] The resin composition (X-14) for tow prepreg was obtained in the same manner as in Example 5 except that 60 parts by mass of the resin mixture (AC-1) was changed to 50 parts by mass, 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 30 parts by mass. Using the obtained resin composition (X-14), a resin molded plate and a tow prepreg (14) were prepared in the same manner as in Example 1, and various evaluations were performed.

[0136] (Example 15: Preparation and evaluation of resin composition for tow prepreg (X-15))

[0137] 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. The same operation as in Example 5 was performed except for the above, to obtain a resin composition (X-15) for tow prepreg. The resin composition (X-15) obtained was used, and the same operation as in Example 1 was performed except for the above, to produce a resin molded plate and a tow prepreg (15), and each evaluation was performed.

[0138] (Example 16: Preparation and evaluation of resin composition for tow prepreg (X-16))

[0139] 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 prepared in the same manner as in Example 1 except that the obtained resin composition (X-16) was used, and various evaluations were performed.

[0140] (Example 17: Preparation and evaluation of resin composition for tow prepreg (X-17))

[0141] The resin composition (X-17) for tow prepreg was obtained in the same manner as in Example 5 except that 60 parts by mass of the resin mixture (AC-1) was changed to 40 parts by mass, the amount of the first (meth) acrylate monomer (b1-1) added was changed to 25 parts by mass, and the amount of the second (meth) acrylate monomer (b2-1) added was changed to 35 parts by mass. Using the obtained resin composition (X-17), a resin molded plate and a tow prepreg (17) were prepared in the same manner as in Example 1, and various evaluations were performed.

[0142] (Example 18: Preparation and evaluation of resin composition for tow prepreg (X-18))

[0143] 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. The same operation as in Example 5 was performed except for the above, to obtain a resin composition (X-18) for tow prepreg. A resin molded plate and a tow prepreg (18) were prepared in the same manner as in Example 1 using the obtained resin composition (X-18), and various evaluations were performed.

[0144] (Comparative Example 1: Preparation and Evaluation of Resin Composition for Tow Prepreg (RX-1))

[0145] 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 prepared in the same manner as in Example 1 except that the obtained resin composition (RX-1) was used, and various evaluations were performed.

[0146] (Comparative Example 2: Preparation and Evaluation of Resin Composition for Tow Prepreg (RX-2))

[0147] The same operation as in Example 5 was performed except that 4 parts by mass of the polytetramethylene ether compound (D'-1) was added instead of the polytetramethylene ether compound (D-1) to obtain a resin composition for tow prepreg (RX-2). A resin molded plate and a tow prepreg (R2) were prepared in the same manner as in Example 1 except that the obtained resin composition (RX-2) was used, and various evaluations were performed.

[0148] (Comparative Example 3: Preparation and Evaluation of Resin Composition for Tow Prepreg (RX-3))

[0149] 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 prepared in the same manner as in Example 1 except that the obtained resin composition (RX-3) was used, and various evaluations were performed.

[0150] (Comparative Example 4: Preparation and Evaluation of Resin Composition for Tow Prepreg (RX-4))

[0151] The addition amount of the first (meth) acrylate monomer (b1-1) was changed to 40 parts by mass, and the second (meth) acrylate monomer (b2-1) was not added at all. The same operation as in Example 5 was performed except for the above, to obtain a tow prepreg resin composition (RX-4). Using the obtained resin composition (RX-4), the same operation as in Example 1 was performed except for this, to produce a resin molded plate and a tow prepreg (R4), and various evaluations were performed.

[0152] (Comparative Example 5: Preparation and Evaluation of Resin Composition for Tow Prepreg (RX-5))

[0153] 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. The same operation as in Example 5 was performed except for the above, to obtain a resin composition for tow prepreg (RX-5). Using the obtained resin composition (RX-5), the same operation as in Example 1 was performed except for this, to produce a resin molded plate and a tow prepreg (R5), and each evaluation was performed.

[0154] (Comparative Example 6: Preparation and Evaluation of Resin Composition for Tow Prepreg (RX-6))

[0155] The above-mentioned second (meth)acrylate monomer (b2-1) was not added at all, and cyclohexyl methacrylate (molecular weight 168, weight loss rate of 11.5% when heated at 50°C for 1 hour under normal pressure) was further added as the (meth)acrylate monomer (B'-1). Except for the above, the same operation as in Example 5 was carried out to obtain a resin composition for tow prepreg (RX-6). Using the obtained resin composition (RX-6), the same operation as in Example 1 was carried out to produce a resin molded plate and a tow prepreg (R6), and various evaluations were performed.

[0156] The evaluation results of the resin compositions (1) to (16) and (R1) to (R8) for tow prepreg obtained above are shown in Tables 1 to 3. In addition, the "total content [mass %] of (b1) + (b2)" in the table represents the total mass of the first (meth)acrylate monomer (b1) and the second (meth)acrylate monomer (b2) relative to 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).

[0157] [Table 1]

[0158]

[0159] [Table 2]

[0160]

[0161] [Table 3]

[0162]

[0163] According to Tables 1 to 3, the strand prepreg resin compositions (X-1) to (X-16) of Examples 1 to 16 can produce cured resin sheets having excellent impact resistance and heat resistance, and thus can realize strand prepregs having excellent fracture toughness and heat resistance. It is also known that the strand prepregs (1) to (16) obtained from the strand prepreg resin compositions (X-1) to (X-16) of Examples 1 to 16 have excellent fracture toughness and heat resistance.

[0164] In contrast, the strand prepreg resin compositions (RX-1) to (RX-3) of Comparative Examples 1 to 3 could not produce cured resin sheets having excellent impact resistance, and the strand prepreg resin composition (RX-4) of Comparative Example 4 could not produce cured resin sheets having excellent heat resistance. In addition, it was found that the strand prepregs (R5) to (R6) obtained from the strand prepreg resin compositions (RX-5) to (RX-6) of Comparative Examples 5 to 6 had low impregnation and relaxation properties.

Claims

1. A resin composition for tow prepreg, characterized in that The invention comprises: 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 acryloyl group or a methacryloyl group at a terminal, and a polymerization initiator (E), The urethane (meth)acrylate resin (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) comprises a first (meth)acrylate monomer (b1) having an aromatic skeleton and a weight loss rate of less than 3% when heated at 50° C. for 1 hour at normal pressure, 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. for 1 hour at normal pressure, The molecular weight of the polyether segment of the polytetramethylene ether compound (D) is 1,000 or more and 3,000 or less.

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

3. The resin composition for tow prepreg according to claim 1 or 2, wherein The content of the polytetramethylene ether compound (D) is 1 to 20 parts by mass based on 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. The resin composition for tow prepreg according to claim 1 or 2, wherein The polyol (a2) is an alkylene oxide adduct of a bisphenol compound.

5. The resin composition for tow prepreg 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 prepreg according to claim 1 or 2 and a reinforcing fiber bundle, and The tow prepreg resin composition is impregnated into the reinforcing fiber bundle.

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