Resin composition for prepregs and prepregs
A resin composition for prepregs, featuring a urethane (meth)acrylate resin and dicyclopentanyl methacrylate, addresses impregnation and resistance issues, resulting in high-quality molded articles with improved heat and impact resistance.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- DIC CORP
- Filing Date
- 2025-05-29
- Publication Date
- 2026-06-05
Smart Images
Figure 2026092648000001 
Figure 2026092648000002
Abstract
Description
Technical Field
[0001] The present invention relates to a resin composition for prepreg and a prepreg.
Background Art
[0002] Fiber reinforced resin composite materials obtained by impregnating reinforcing fibers such as carbon fibers and glass fibers with a resin are lightweight and excellent in heat resistance and mechanical strength, and are therefore used in various applications such as automotive parts, aircraft parts, housing equipment parts, and sports parts. Conventionally, as a method for molding a fiber reinforced resin composite material, a method of curing and molding using an intermediate material called a prepreg in which a thermosetting resin is impregnated into reinforcing fibers by autoclave molding, press molding, sheet winding molding, pultrusion molding, etc. is known. For example, Patent Document 1 discloses that a resin composition for prepreg containing a urethane (meth) acrylate resin, a polymerization initiator, and a thermoplastic polyurethane resin is prepared, and a prepreg obtained by impregnating the resin composition for prepreg into reinforcing fibers is press-molded to produce a molded body excellent in flexibility, impact resistance, and heat resistance.
[0003] On the other hand, high-pressure tanks for storing natural gas, hydrogen gas, etc. are required to have particularly excellent durability and impact resistance. As a method for manufacturing the high-pressure tank, for example, Patent Document 2 discloses a manufacturing method using a tow prepreg in which a resin is impregnated into a reinforcing fiber bundle (tow) such as carbon fiber and glass fiber. According to Patent Document 2, it is said that a lightweight and high-strength high-pressure tank can be manufactured.
[0004] Therefore, as a molding material for manufacturing a high-pressure tank, a tow prepreg obtained by impregnating a tow with the resin composition for prepreg disclosed in Patent Document 1 can be considered.
[0005] However, the resin composition for prepregs disclosed in Patent Document 1 has the disadvantage of being difficult to impregnate into tow due to its high viscosity. Furthermore, the resin composition for prepregs disclosed in Patent Document 1 also has the disadvantage of being difficult to further improve heat resistance because it contains about 20% by mass of thermoplastic polyurethane resin.
[0006] Therefore, in order to improve impregnation and heat resistance, it is conceivable to prepare the prepreg resin composition disclosed in Patent Document 1 using methyl methacrylate monomer instead of the thermoplastic resin. However, if a high-pressure tank is manufactured using a tow prepreg impregnated with the obtained resin composition, a large amount of methyl methacrylate may volatilize during manufacturing, which may reduce the quality stability of the high-pressure tank. [Prior art documents] [Patent Documents]
[0007] [Patent Document 1] Patent No. 6610982 [Patent Document 2] Japanese Patent Publication No. 2022-22548 [Overview of the project] [Problems that the invention aims to solve]
[0008] The problem that the present invention aims to solve is to provide a resin composition for prepregs that has excellent impregnation properties into reinforcing fibers and can realize molded articles with excellent impact resistance and heat resistance. Furthermore, the problem that the present invention aims to solve is to provide a prepreg that can realize molded articles with excellent impact resistance and heat resistance. [Means for solving the problem]
[0009] The inventors have discovered that by using a specific (meth)acrylate monomer in a specific content range, it is possible to obtain a resin composition for prepregs that exhibits excellent impregnation into reinforcing fibers and can produce molded articles with excellent impact resistance and heat resistance, thus completing the present invention.
[0010] In other words, the present invention has the following aspects.
[0011] (1) A resin composition for prepregs containing a urethane (meth)acrylate resin (A), a (meth)acrylate monomer (B), and a polymerization initiator (C), A resin composition for prepregs in which the urethane (meth)acrylate resin (A) is a reaction product of polyisocyanate (a1), a polyol having an aromatic skeleton (a2), and hydroxyalkyl (meth)acrylate (a3), and the (meth)acrylate monomer (B) contains at least dicyclopentanyl methacrylate, the content of dicyclopentanyl methacrylate is 50% by mass or more of the total content of the (meth)acrylate monomer (B), and the total content of the (meth)acrylate monomer (B) is 25% by mass or more and 50% by mass or less of the total mass of the urethane (meth)acrylate (A) and the (meth)acrylate monomer (B).
[0012] (2) The resin composition for prepreg according to (1), further comprising a (meth)acrylate monomer (B) having a weight loss rate of less than 3% when heated at normal pressure, 50°C, and for 1 hour.
[0013] (3) The prepreg resin composition according to (1) or (2), further comprising a (meth)acrylate monomer (B) having an aromatic skeleton and / or an alicyclic skeleton in the molecule and having one or two (meth)acrylate groups.
[0014] (4) The resin composition for prepreg according to claim 1 or claim 2 of any one of (1) to (3), further comprising a (meth)acrylate monomer (B) having a (meth)acrylate group equivalent of 150 or more and 400 or less.
[0015] (5) The resin composition for prepregs according to any one of (1) to (4) above, wherein the polyol (a2) is an oxyalkylene adduct of a bisphenol compound.
[0016] (6) A prepreg comprising the resin composition for prepregs described in any one of items (1) to (5) above, and reinforcing fibers, wherein the resin composition for prepregs is impregnated into the reinforcing fibers. [Effects of the Invention]
[0017] According to the present invention, a resin composition for prepregs is available that exhibits excellent impregnation properties into reinforcing fibers and enables the creation of molded articles with excellent impact resistance and heat resistance. Furthermore, according to the present invention, a prepreg is available that enables the creation of molded articles with excellent impact resistance and heat resistance. [Modes for carrying out the invention]
[0018] The resin composition for prepreg according to an embodiment of the present invention is a resin composition for prepreg containing a urethane (meth)acrylate resin (A), a (meth)acrylate monomer (B), and a polymerization initiator (C), wherein 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) contains at least dicyclopentanyl methacrylate (B-1), the content of the dicyclopentanyl methacrylate (B-1) is 50% by mass or more based on the total content of the (meth)acrylate monomer (B), and the total content of the (meth)acrylate monomer (B) is 25% by mass or more and 50% by mass or less based on the total mass of the urethane (meth)acrylate (A) and the (meth)acrylate monomer (B).
[0019] 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).
[0020] Since the heat resistance of the molded product is further improved, the polyisocyanate (a1) preferably contains a polyisocyanate having an aromatic skeleton or an alicyclic skeleton. These polyisocyanates (a1) can be used alone or in combination of two or more.
[0021] The polyisocyanate (a1) is, for example, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, a carbodiimide-modified product of 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, a nurate-modified product of diphenylmethane diisocyanate, a burette-modified product, a urethane imine-modified product, a polyol-modified product modified with a polyol having a number average molecular weight of 1,000 or less such as diethylene glycol or dipropylene glycol, tolylene diisocyanate (TDI), tolidine diisocyanate, xylylene diisocyanate, 1,5-naphthalene diisocyanate, tetramethylxylylene diisocyanate and other aromatic polyisocyanates; alicyclic polyisocyanates such as isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, norbornene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate, a nurate-modified product of hexamethylene diisocyanate, a burette-modified product, an adduct product, dimer acid diisocyanate, and the like.
[0022] Among these, since the heat resistance of the molded product is further improved, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, a carbodiimide-modified product of 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, norbornene diisocyanate, xylylene diisocyanate, and isophorone diisocyanate (IPDI) are preferable. These polyisocyanates (a1) can be used alone or in combination of two or more.
[0023] The polyol (a2) has an aromatic skeleton. Examples include alkylene oxide adducts of bisphenol compounds such as alkylene oxide adducts of bisphenol A, bisphenol S, and 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, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, etc. Among these, alkylene oxide adducts of bisphenol compounds are preferred from the viewpoint of balancing compatibility, heat resistance, water resistance, and strength properties. More preferably, ethylene oxide adducts of bisphenol compounds are used, with an average number of added moles of 2 to 10 moles.
[0024] 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 due to the balance of strength and physical properties. These hydroxyalkyl (meth)acrylates (a3) can be used individually or in combination of two or more.
[0025] Furthermore, if necessary, other polyols other than the polyols (a2) to (a3) can be used as raw materials for the urethane (meth)acrylate (A). Examples of other polyols include polyester polyols, acrylic polyols, polyether polyols, polycarbonate polyols, and polyalkylene polyols. These other polyols can be used within a range that ensures the heat resistance of the resulting molded article.
[0026] The molar ratio (a2 / a3) of the polyol (a2) to the hydroxyalkyl (meth)acrylate (a3) is preferably 60 / 40 to 20 / 80, and more preferably 50 / 50 to 30 / 70, as this improves heat resistance and curability. The molar ratio is calculated based on hydroxyl group equivalents (g / eq).
[0027] The molar ratio (NCO / OH) of the isocyanate group (NCO) of the isocyanate compound that serves as the raw material for the urethane (meth)acrylate (A) to the hydroxyl group (OH) of the compound having a hydroxyl group is preferably 0.7 or more and 1.1 or less, and more preferably 0.9 or more and 1.0 or less, in terms of the balance between heat resistance and strength properties.
[0028] The prepreg resin composition according to this embodiment essentially contains dicyclopentanyl methacrylate (B-1) as the (meth)acrylate monomer (B). Dicyclopentanyl methacrylate is also known as tricyclo[5.2.1.0(2,6)]decane-8-yl-methacrylate.
[0029] The prepreg resin composition according to this embodiment is characterized in that the content of dicyclopentanyl methacrylate (B-1) is 50% by mass or more relative to the total content of (meth)acrylate monomer (B), and the total content of (meth)acrylate monomer (B) is 25% by mass or more and 50% by mass or less relative to the total mass of urethane (meth)acrylate (A) and (meth)acrylate monomer (B).
[0030] The resin composition for prepregs of this embodiment provides a prepreg resin composition that exhibits excellent impregnation into reinforcing fibers and enables the creation of molded articles with excellent impact resistance and heat resistance. Furthermore, since cyclopentanyl methacrylate (B-1) is a low-volatility compound, it suppresses volatilization during the production of molded articles from prepregs, thereby ensuring the quality stability of the molded articles.
[0031] If the resin composition for the prepreg does not contain dicyclopentanyl methacrylate (B-1), or if its content is less than 50% by mass of the total content of the (meth)acrylate monomer (B), then excellent impregnation into the reinforcing fibers cannot be ensured, or the impact resistance or heat resistance of the resulting molded article cannot be ensured.
[0032] Furthermore, in the prepreg resin composition of this embodiment, the content of dicyclopentanyl methacrylate (B-1) is more preferably 20% by mass or more relative to the total mass of the urethane (meth)acrylate (A) and the (meth)acrylate monomer (B) from the viewpoint of ensuring heat resistance, and is preferably 45% by mass or less from the viewpoint of compatibility with urethane (meth)acrylate (A).
[0033] In a prepreg resin composition, if the total content of (meth)acrylate monomer (B) is less than 25% by mass relative to the total mass of urethane (meth)acrylate (A) and (meth)acrylate monomer (B), the viscosity of the prepreg resin composition increases, impregnation into reinforcing fibers decreases, and the heat resistance of the molded article produced from the prepreg using the prepreg resin composition decreases. On the other hand, if the total content of (meth)acrylate monomer (B) exceeds 50% by mass relative to the total mass of urethane (meth)acrylate (A) and (meth)acrylate monomer (B), the impact resistance of the molded article produced from the prepreg resin composition decreases.
[0034] Furthermore, in the resin composition for prepregs of this embodiment, the balance between resin impregnation, productivity, and molded product quality is further improved, so it is more preferable that the content of the (meth)acrylate monomer (B) in the resin composition for prepregs be 30% by mass or more and 45% by mass or less, based on the total mass of the urethane (meth)acrylate (A) and the (meth)acrylate monomer (B).
[0035] The prepreg resin composition of this embodiment may contain a (meth)acrylate monomer (B-2) other than dicyclopentanyl methacrylate (B-1). It is preferable to use a (meth)acrylate monomer (B-2) that exhibits a weight loss rate of less than 3% when heated at 50°C for 1 hour under normal pressure. Since the (meth)acrylate monomer is a low-volatility compound, it suppresses volatilization during the production of molded articles from the prepreg, ensuring the quality stability of the molded articles. Examples of the (meth)acrylate monomer include phenoxyethyl methacrylate, di(meth)acrylate of an ethylene oxide adduct of bisphenol A, and tricyclodecanedimethanol di(meth)acrylate. From the viewpoint of balancing volatility and heat resistance, di(meth)acrylate of an ethylene oxide adduct of bisphenol A and tricyclodecanedimethanol di(meth)acrylate are preferred.
[0036] The aforementioned weight loss rate (%) can be measured, for example, as follows: 2.0 to 2.1 g of (meth)acrylate monomer at room temperature is weighed into a tin petri dish with an inner diameter of approximately 64 mm, left to stand for 1 minute, and then placed on a hot plate with a surface temperature of 50°C under normal pressure for 1 hour. After 1 hour, the petri dish is retrieved, and after 10 to 20 seconds at room temperature, its weight is measured to four decimal places using a precision balance, and the heat loss (%) is calculated to one decimal place. The sample size N should be 2 or more, and the average value should be taken.
[0037] As the (meth)acrylate monomer (B-2), it is also possible to use a methacrylate monomer with a weight loss rate of 3% or more, but in that case, the content should be adjusted considering the amount of volatilization during the manufacture of the molded product. For example, when using methyl methacrylate, it is preferable that its content be 5% by mass or less of the total content of (meth)acrylate monomer (B).
[0038] Furthermore, it is preferable to use a (meth)acrylate monomer (B-2) other than dicyclopentanyl methacrylate (B-1) that has an aromatic skeleton and / or an alicyclic skeleton in its molecule and also has one or two (meth)acrylate groups.
[0039] (Meth)acrylate monomers having an aromatic or alicyclic skeleton in their molecule tend to exhibit both heat resistance and impact resistance more easily than (meth)acrylate monomers having an aliphatic skeleton in their molecule. Furthermore, (meth)acrylate monomers having one (meth)acrylate group in their molecule exhibit excellent dilution effects on the urethane (meth)acrylate resin (A), contributing to viscosity reduction in the prepreg resin composition and improved fracture toughness of the molded article. In addition, (meth)acrylate monomers having two (meth)acrylate groups in their molecule exhibit inferior dilution effects compared to (meth)acrylate monomers having one (meth)acrylate group, but contribute to improved heat resistance of the molded article. Based on the above, the resin composition for prepregs according to this embodiment is more preferably a combination of dicyclopentanyl methacrylate, a (meth)acrylate monomer having an aromatic or alicyclic skeleton in its molecule and one (meth)acrylate group, and a (meth)acrylate monomer having an aromatic or alicyclic skeleton in its molecule and two (meth)acrylate groups. By using both, the impregnation into reinforcing fibers can be further improved, and the impact resistance and heat resistance of the resulting molded article can be further improved. When using both, the content ratio (mass ratio) of the two is preferably in the range of 100:0 to 60:40, and more preferably in the range of 90:10 to 65:35, taking into consideration the balance between viscosity and heat resistance.
[0040] Examples of (meth)acrylate monomers having an aromatic or alicyclic skeleton and one (meth)acrylate group in the molecule include phenoxyethyl methacrylate, 2-methylphenoxyethyl methacrylate, tricyclo[5.2.1.0(2,6)]decane-8-yl acrylate (commonly known as "dicyclopentanyl acrylate"), bornyl methacrylate, isobornyl methacrylate, adamantyl (meth)acrylate, 4-t-butylcyclohexyl methacrylate, glycerol carbonate methacrylate, etc. From the viewpoint of compatibility with urethane (meth)acrylate (A), phenoxyethyl acrylate and 2-methylphenoxyethyl methacrylate are preferred.
[0041] Examples of (meth)acrylate monomers having an aromatic or alicyclic skeleton and two (meth)acrylate groups in the molecule include dimethacrylate, an ethylene oxide adduct of bisphenol A, dimethacrylate, an ethylene oxide adduct of bisphenol F, and 9,9-bis[4-(2-methacryloyloxyethoxy)phenyl]fluorene. Other examples include hydrogenated bisphenol A dimethacrylate, tricyclodecane dimethanol di(meth)acrylate, dimethacrylate, an ethylene oxide adduct of isosorbide, and an ethylene oxide adduct of hydrogenated bisphenol A. Among these, tricyclodecane dimethanol di(meth)acrylate and di(meth)acrylate, an ethylene oxide adduct of bisphenol A, are preferred. In this case, it is more preferable that the average number of moles of ethylene oxide added is 2 to 10 moles.
[0042] Furthermore, from the viewpoint of improving heat resistance, it is preferable to use a (meth)acrylate monomer (B-2) having a (meth)acrylate group equivalent of 150 to 400. Examples of the (meth)acrylate monomer include tricyclodecanedimethanol di(meth)acrylate, dimethacrylate, an ethylene oxide adduct of bisphenol A (2 to 6 moles), and 9,9-bis[4-(2-methacryloyloxyethoxy)phenyl]fluorene. From the viewpoint of achieving both compatibility with urethane (meth)acrylate (A) and heat resistance, tricyclodecanedimethanol di(meth)acrylate and dimethacrylate, an ethylene oxide adduct of bisphenol A (2 to 6 moles), are preferred.
[0043] It is preferable to use a (meth)acrylate monomer (B-2) having a molecular weight of 200 to 800. The (meth)acrylate monomer (B-2) has excellent dilution properties for urethane (meth)acrylate resin (A), making it suitable for viscosity adjustment in prepreg resin compositions. Furthermore, because it is not easily volatilized, it can suppress the increase in viscosity of the prepreg resin composition during prepreg production, and it can prevent volatilization during the production of molded articles using the obtained prepreg, thereby preventing a decrease in the quality stability of the resulting molded articles. Examples of the (meth)acrylate monomer include phenoxyethyl methacrylate, 2-methylphenoxyethyl methacrylate, tricyclodecanedimethanol di(meth)acrylate, and dimethacrylate, which is a 2-6 molar adduct of bisphenol A to ethylene oxide. From the viewpoint of balancing volatility and heat resistance, tricyclodecanedimethanol di(meth)acrylate and dimethacrylate, which is a 2-6 molar adduct of bisphenol A to ethylene oxide, are preferred.
[0044] The polymerization initiator (C) is not particularly limited, but organic peroxides are preferred, and examples include diacyl peroxide compounds, peroxyester compounds, hydroperoxide compounds, ketone peroxide compounds, alkyl perester compounds, parkerized compounds, peroxyketals, etc., which can be appropriately selected depending on the molding conditions. These polymerization initiators (C) can be used alone or in combination of two or more. A photopolymerization initiator may also be used in combination.
[0045] Furthermore, as the polymerization initiator (C), it is preferable to use one that has a temperature of 60°C to 110°C to obtain a half-life of 10 hours, in order to shorten the molding time. The polymerization initiator (C) can extend the life of the prepreg at room temperature and can be cured in a short time by heating; for example, the prepreg can be cured by heating at 170°C for 5 minutes. Moreover, it is more preferable that the polymerization initiator (C) has a temperature of 70°C to 105°C to obtain a half-life of 10 hours. 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-butyl4,4-di(t-butylperoxy)valerate. The optimal organic peroxide is selected and used according to the molding conditions.
[0046] The amount of polymerization initiator (C) added is preferably in the range of 0.5 to 5 parts by mass per 100 parts by mass of the total of the urethane (meth)acrylate resin (A) and the (meth)acrylate monomer (B), since both curing properties and storage stability are excellent.
[0047] The prepreg resin composition of this embodiment may contain other components besides those described above. Other components may include, for example, thermosetting resins, thermoplastic resins, polymerization inhibitors, curing accelerators, fillers, low-shrinkage agents, mold release agents, thickeners, devisers, pigments, antioxidants, plasticizers, flame retardants, antibacterial agents, UV stabilizers, reinforcing materials, photopolymerization initiators, and the like.
[0048] Examples of the thermosetting resins include vinyl ester resins, unsaturated polyester resins, epoxy resins, and bismaleimide resins. These thermosetting resins can be used individually or in combination of two or more types.
[0049] Examples of the thermoplastic resins include polyamide resins, polycarbonate resins, polyurethane resins, polypropylene resins, polyethylene resins, polystyrene resins, acrylic resins, polybutadiene resins, polyisoprene resins, and those modified by copolymerization or the like. Among these, polyamide resins and polyurethane resins are preferred due to their high effectiveness in improving brittleness. These thermoplastic resins can be used individually or in combination of two or more. The thermoplastic resin can also be added in particulate form or melted and mixed in. When using particulate thermoplastic resin, the particle size is preferably 30 μm or less, and more preferably 5 to 20 μm, from the viewpoint of dispersibility in fibers. The content of the thermoplastic resin is preferably 5% by mass or less relative to the total prepreg resin composition in order to ensure heat resistance.
[0050] Examples of polymerization inhibitors include hydroquinone, trimethylhydroquinone, pt-butylcatechol, t-butylhydroquinone, toluhydroquinone, p-benzoquinone, naphthoquinone, hydroquinone monomethyl ether, phenothiazine, bis(2,2,6,6-tetramethyl-4-piperidyl-1-oxyl) sebacate, copper naphthenate, and copper chloride. These polymerization inhibitors can be used individually or in combination of two or more.
[0051] The aforementioned fillers include inorganic compounds and organic compounds, and can be used to adjust the physical properties of molded products, such as strength, elastic modulus, impact strength, and fatigue durability.
[0052] Examples of the inorganic compounds include calcium carbonate, magnesium carbonate, barium sulfate, mica, talc, kaolin, clay, celite, barite, baryta, silica, silica sand, dolomite limestone, gypsum, aluminum powder, hollow balloons, alumina, glass powder, aluminum hydroxide, granite, zirconium oxide, titanium oxide, molybdenum dioxide, and iron powder.
[0053] The aforementioned organic compounds include natural polysaccharide powders such as cellulose and chitin, and synthetic resin powders. The synthetic resin powders can include powders of organic materials composed of hard resins, soft rubbers, elastomers, or polymers (copolymers), or particles having a multilayer structure such as a core-shell type. Specifically, examples include acrylic particles, polyamide particles, particles made of butadiene rubber and / or acrylic rubber, urethane rubber, silicone rubber, polyimide resin powder, fluororesin powder, and phenolic resin powder. These fillers can be used individually or in combination of two or more types.
[0054] Examples of the mold release agent include zinc stearate, calcium stearate, paraffin wax, polyethylene wax, and carnauba wax. Preferably, paraffin wax, polyethylene wax, and carnauba wax are used. These mold release agents can be used individually or in combination of two or more.
[0055] Examples of the thickening agents include polyisocyanate compounds and acrylic resin-based fine particles, which can be appropriately selected depending on the handling requirements of the prepreg. These thickening agents can be used individually or in combination of two or more types.
[0056] The photopolymerization initiator is a polymerization initiator that generates radicals upon light irradiation, and any known photopolymerization initiator can be used without particular limitation. As the photopolymerization initiator, alkylphenone-based radical initiators, benzophenone-based radical initiators, benzoin-based radical initiators, acylphosphine oxide-based radical initiators, etc., are preferred because they are readily available.
[0057] The resin composition for prepregs is produced by mixing a urethane (meth)acrylate resin (A), the (meth)acrylate monomer (B), and a polymerization initiator (C). For example, one method involves pre-mixing an aromatic polyol (a2), a hydroxyalkyl (meth)acrylate (a3), and a (meth)acrylate monomer (B), then adding and reacting a polyisocyanate (a1) to obtain a urethane (meth)acrylate resin (A), and then obtaining a mixture of the urethane (meth)acrylate resin (A), (meth)acrylate monomer (B), and polymerization initiator (C). Another method involves partially dividing the polyisocyanate (a1) and adding and reacting the remainder during prepreg production. A method with excellent mass productivity is appropriately selected.
[0058] The resin composition for prepregs described above is impregnated into reinforcing fibers and used as a prepreg. That is, the prepreg of this embodiment contains the resin composition for prepregs described above and reinforcing fibers, and is characterized in that the resin composition for prepregs is impregnated into the reinforcing fibers. According to the prepreg of this embodiment, a molded article with excellent impact resistance and heat resistance can be provided.
[0059] When impregnating reinforcing fibers with a prepreg resin composition, the temperature of the prepreg resin composition is preferably around 20 to 60°C, and more preferably around 30 to 50°C from the viewpoint of preventing abnormal decomposition of peroxides and achieving low viscosity.
[0060] Examples of the reinforcing fibers include carbon fibers, glass fibers, silicon carbide fibers, alumina fibers, boron fibers, metal fibers, aramid fibers, and organic fibers such as Tetron fibers. Carbon fibers, glass fibers, and aramid fibers are preferred because they yield molded products with higher strength and elasticity, and carbon fibers are even more preferred for manufacturing high-pressure tanks for storing natural gas or hydrogen gas. These reinforcing fibers can be used individually or in combination of two or more types.
[0061] Various types of carbon fibers can be used, such as polyacrylonitrile-based, pitch-based, and rayon-based fibers. Among these, polyacrylonitrile-based fibers are preferred because they allow for easy acquisition of high-strength carbon fibers.
[0062] When manufacturing tow prepregs, it is preferable to use tow or braided cords, which are formed by converging reinforcing fiber filaments, as the shape of the reinforcing fibers.
[0063] When manufacturing sheet prepregs, unidirectional materials made of reinforcing fibers, woven fabrics, knitted fabrics, etc., made from the unidirectional material are preferred. Unidirectional materials obtained by defibrating the reinforcing fiber tow and aligning them in one direction may also be used.
[0064] In this embodiment, the content of the reinforcing fiber bundle in the prepreg is preferably in the range of 50 to 85% by mass, and more preferably in the range of 60 to 80% by mass, since this further improves the mechanical strength of the resulting molded product.
[0065] The prepreg of this embodiment can be manufactured by various known methods, but a manufacturing method that does not use any diluent solvents is preferable.
[0066] When manufacturing tow prepregs, it is desirable to heat the prepreg resin composition to reduce its viscosity, bring it into contact with reinforcing fiber bundles aligned in one direction using a resin bath or coater, and then impregnate the reinforcing fiber bundles with the prepreg resin composition while applying pressure with a rotating roll, before winding it onto a bobbin, roll, etc. At this time, from the viewpoint of productivity, the viscosity of the prepreg resin composition is preferably in the range of 0.1 to 5 Pa·S at a temperature range of 30 to 60°C. Fine adjustments are made to the resin composition so that the viscosity of the prepreg resin composition falls within the above range.
[0067] In the case of manufacturing a sheet prepreg, it is preferable to heat the prepreg resin composition to reduce its viscosity, then coat it onto one side of a release PET film, bring it into contact with a reinforcing fiber fabric, sandwich it with another release PET film, and then impregnate the reinforcing fiber fabric with the prepreg resin composition while applying pressure with a rotating roll, before winding it onto a paper tube or the like. At this time, from the viewpoint of productivity, the viscosity of the prepreg resin composition is preferably in the range of 0.5 to 10 Pa·s at a temperature range of 30 to 60°C.
[0068] One method for obtaining molded products from the obtained tow prepreg is to unwind the tow prepreg from a bobbin or the like, wrap it around a resin or metal liner, then wrap a shrink film or the like around the surface, and then heat-cure it in an oven to produce molded products such as gas tanks and pipes. Alternatively, by wrapping the tow prepreg around a metal rod or pipe and then performing a similar process and heat-curing it, fiber-reinforced metal components can be produced. Examples include spindle shafts, rotary rolls, and power transmission shafts. The combination and configuration can be appropriately selected depending on the product.
[0069] One method for obtaining molded products from the resulting sheet prepreg involves cutting it to the required size, stacking multiple sheets according to the desired molded product, and then creating a three-dimensional molded product using an autoclave or hot mold.
[0070] The molded articles obtained from the prepreg of this embodiment have excellent impact resistance and heat resistance, and can therefore be suitably used in automotive components, railway vehicle components, aerospace components, ship components, housing equipment components, sports components, light vehicle components, building and civil engineering components, and in particular high-pressure tanks for storing natural gas and hydrogen gas, automobile drive shafts, aircraft skeletal components, and the like. [Examples]
[0071] The present invention will be described in more detail below with reference to specific examples.
[0072] (Synthesis Example 1: Preparation of urethane (meth)acrylate resin (A-1) and resin mixture (AM-1)) In a 5L flask equipped with a thermometer, nitrogen and air inlet tubes, and a stirrer, 366g of Nieuport BPE-20 (manufactured by Sanyo Chemical Industries, Ltd.: EO adduct of bisphenol A, hydroxyl group equivalent: 161g / eq) and 483g of Nieuport BPE-40 (manufactured by Sanyo Chemical Industries, Ltd.: EO adduct of bisphenol A, hydroxyl group equivalent: 203g / eq) were added. Stirring was started at 60°C, then the temperature was raised to 100°C and the mixture was stirred for 1 hour. After confirming that the mixture was uniformly dissolved, it was cooled to 100°C, and 936g of hydroxyethyl methacrylate and 3.2g of t-butyl hydroquinone were added. The mixture was stirred at 60°C for 1 hour, and then stirring was continued while cooling to 30°C. Next, 720 g of 4,4'-diphenylmethane diisocyanate was added in three equal parts, and after 0.5 hours, 720 g of 2,4'-diphenylmethane diisocyanate was added in three equal parts, and the temperature was raised to 70°C while taking care to avoid exothermic reactions. After holding at 70°C for 6 hours, the contents were removed from the reaction vessel. As a result, a resin mixture (AM-1) containing a urethane (meth)acrylate resin (A), which is a reaction product of a polyisocyanate, a polyol having an aromatic skeleton, and a hydroxyalkyl (meth)acrylate, was obtained. The resin mixture (AM-1) contains 99.9% by mass of the urethane (meth)acrylate resin (A-1) and 0.1% by mass of the t-butyl hydroquinone.
[0073] (Synthesis Example 2: Preparation of urethane (meth)acrylate resin intermediate (A-2a) and resin mixture (AM-2)) In a 5L flask equipped with a thermometer, nitrogen and air inlet tubes, and a stirrer, 305g of Nieuport BPE-20 (manufactured by Sanyo Chemical Industries, Ltd.: EO adduct of bisphenol A, hydroxyl equivalent: 161g / eq) and 422g of Nieuport BPE-40 (manufactured by Sanyo Chemical Industries, Ltd.: EO adduct of bisphenol A, hydroxyl equivalent: 203g / eq) were added. Stirring was started at 60°C, then the temperature was raised to 100°C and the mixture was stirred for 1 hour. After confirming that the mixture was uniformly dissolved, it was cooled to 100°C, and 1131g of hydroxyethyl methacrylate and 3.0g of t-butyl hydroquinone were added. The mixture was stirred at 60°C for 1 hour, and then stirring was continued while cooling to 30°C. Next, 1207g of 4,4'-diphenylmethane diisocyanate was added in 6 portions, and the temperature was raised to 60°C while taking care to avoid exothermic reactions. After being held at 60°C for 6 hours, the contents were removed from the reaction vessel. This yielded a resin mixture (AM-2) containing a urethane (meth)acrylate resin intermediate (A'-2), which is a reaction product of polyisocyanate, a polyol having an aromatic skeleton, and hydroxyalkyl (meth)acrylate. The resin mixture (AM-2) contained 99% by mass of the urethane (meth)acrylate resin intermediate (A'-2) and 0.1% by mass of the t-butyl hydroquinone. The hydroxyl equivalent of the resin mixture (AM-2) was 963 g / eq.
[0074] (Synthesis Example 3: Preparation of Polyisocyanate Mixture (a1-1) for Post-Addition) A mixture of polymethylene polyphenyl polyisocyanate and MDI (Tosoh Corporation's "Millionate MR-200", with a polymethylene polyphenyl polyisocyanate content of 56%) of 500 g and 4,4'-diphenylmethane diisocyanate, which was heated and dissolved at 60°C, were placed in a 1 kg metal can heated at 60°C, purged with nitrogen, and then quickly shaken to prepare a polyisocyanate mixture for post-addition (a1-1). The isocyanate equivalent of the polyisocyanate mixture (a1-1) was 131 g / eq.
[0075] (Example 1: Resin composition for tow prepreg (X-1)) [Preparation and evaluation of resin composition for tow prepreg (X-1)] The product contains 24.5 parts by mass of FA-513M (manufactured by Resonaq Corporation, dicyclopentanyl methacrylate, molecular weight 220, purity 98.3%, weight loss rate 1.7% when heated at 50°C for 1 hour under normal pressure) as dicyclopentanyl methacrylate (B-1), 6.1 parts by mass of NK ester PEM-100 (manufactured by Shin Nakamura Chemical Co., Ltd., phenoxyethyl methacrylate, molecular weight 206, weight loss rate 0.7% when heated at 50°C for 1 hour under normal pressure) as (meth)acrylate monomer (B-2a), and NK ester as (meth)acrylate monomer (B-2b). 13.0 parts by mass of DCP (manufactured by Shin Nakamura Chemical Co., Ltd., tricyclodecanedimethanol dimethacrylate, molecular weight 332, (meth)acrylic group equivalent 166, weight loss rate 0.3% when heated at 50°C for 1 hour under normal pressure) and 56.46 parts by mass of the resin mixture (AM-1) obtained in Synthesis Example 1 and 0.02 parts by mass of parabenzoquinone were placed in a stainless steel container and heated in a 50°C drying oven for 2 hours. After confirming that it had dissolved, it was stirred and mixed. Next, 2.0 parts by mass of polymerization initiator (C-1) (manufactured by Kayaku Nurion Co., Ltd., "Triganox 122-C80", organic peroxide) were mixed in to prepare a resin composition (X-1) for tow prepreg.
[0076] The resin composition (X-1) contains dicyclopentanyl methacrylate (B-1) as (meth)acrylate monomer (B), and (meth)acrylate monomers (B-1), (B-2a), and (B-2b). In the resin composition (X-1), the total content of (meth)acrylate monomer (B) is 43.6% by mass relative to the total mass of the urethane (meth)acrylate resin (A-1) and the (meth)acrylate monomer (B), and the content of dicyclopentanyl methacrylate (B-1) is 56.2% by mass relative to the total content of (meth)acrylate monomer (B).
[0077] [Fabrication of resin molded plate A and evaluation of impact resistance] The obtained resin composition (X-1) was poured between two glass plates with a gap of 6 mm maintained between them. The plate was heated in a furnace from room temperature to 150°C in 1.5 hours, held at 150°C for 1 hour, then cooled from 150°C to 80°C in 30 minutes, and then allowed to cool at room temperature to produce a 6 mm thick resin molded plate A made of cured resin composition (X-1).
[0078] From the obtained resin molded plate A, test specimens measuring 12.7 mm in width and 55 mm in length were cut using a diamond cutter, and a predetermined pre-crack was made in each specimen. For the obtained test specimens (number of samples n=10), the fracture toughness value (K) was determined according to ASTM D5045-99. IC The impact resistance was evaluated based on the average value of the measured values according to the following criteria. ○:K IC 0.9 MPa·m 0.5 It exceeds ×:K IC 0.9 MPa·m 0.5 The following is
[0079] [Fabrication of resin molded board B and evaluation of heat resistance] The obtained resin composition (X-1) was poured between two glass plates with a gap of 4 mm maintained between them, and the temperature was raised in a heating furnace from room temperature to 150°C in 1.5 hours, held at 150°C for 1 hour, then cooled from 150°C to 80°C in 30 minutes, and then allowed to cool at room temperature to produce a 4 mm thick resin molded plate B made of cured resin composition (X-1).
[0080] From the obtained resin molded plate B, test pieces measuring 10 mm in width and 45 mm in length were cut using a diamond cutter. For the obtained test pieces (number of samples n=2), dynamic viscoelasticity was measured using the RSA-G2 dynamic viscoelasticity measuring device manufactured by TA Instruments Inc., at a measurement frequency of 1 Hz, a heating rate of 5 °C / min, and in a 3-point bending mode in the temperature range of 10 to 200 °C. In the obtained storage modulus E', the intersection point of the approximate straight line of the glass region and the tangent line of the transition region was defined as the glass transition temperature (Tg), and the heat resistance was evaluated from the average value according to the following criteria. ○: Tg is 130℃ or higher ×: Tg is less than 130°C
[0081] [Preparation of tow prepreg] A tow prepreg was prepared using the obtained resin composition (X-1) and reinforcing fibers in a prepreg manufacturing apparatus equipped with a creel, resin bath, resin coating roll, impregnation roll, nip roll, winder, and tension control machine, as follows. First, the resin composition (X-1), adjusted to a temperature of 50°C, was coated onto one side of a reinforcing fiber bundle of high-strength carbon fiber T700SC-12K (manufactured by Toray Industries, Inc.) so that the content of the resin composition (X-1) in the tow prepreg was 24% by mass. Subsequently, the tow prepreg (1) was prepared by passing the bundle through an impregnation roll and a nip roll to impregnate the inside of the reinforcing fiber bundle with the resin composition (X-1). The manufacturing apparatus was operated at 20 m / min for 1 hour. The obtained tow prepreg (1) was wound onto a bobbin, packaged in an oxygen barrier film, placed in an oxygen barrier film bag, purged with nitrogen, sealed, and left to stand at room temperature.
[0082] [Evaluation of resin impregnation properties of tow prepreg] The obtained tow prepreg (1) was removed from the bag 7 days after manufacturing, and its resin impregnation properties were evaluated by visual observation. ○: The resin is uniformly impregnated on both sides of the reinforcing fiber bundle. △: A small amount of resin-unimpregnated fibers are present on both sides of the reinforcing fiber bundle. ×: Both sides of the reinforcing fiber bundle are not homogeneous, and there are many fibers that are not impregnated with resin.
[0083] [Evaluation of the comfort-relieving properties of touplipreg] The tow prepreg (1) obtained as described above was removed from the bag seven days after manufacturing, fixed to a creel, and the tip of the tow prepreg was wound onto an empty bobbin and unwound at a speed of 30 m / min. The unwinding state at that time was evaluated. ○: The tow prepreg could be pulled out completely, and the bobbin rotation speed remained stable from start to finish. △: The tow prepreg could be pulled out completely, but the bobbin rotation speed was unstable. ×: The tow prepreg stuck too strongly to the bobbin, making it impossible to wind the tow prepreg reliably.
[0084] (Example 2: Resin composition for tow prepreg (X-2)) Resin composition (X-2) for tow prepreg was prepared in the same manner as in Example 1, except that the above (meth)acrylate monomer (B-2b) was replaced with 13.0 parts by mass of Miramer M245 (manufactured by Mion Co., Ltd., South Korea; methacrylate of an ethylene oxide adduct of bisphenol A; molecular weight 496; (meth)acrylic group equivalent 248; weight loss rate less than 0.1% when heated at 50°C for 60 minutes under normal pressure) as (meth)acrylate monomer (B-2c). Resin molded plates A and B and tow prepreg (2) were prepared in the same manner as in Example 1, except that resin composition (X-2) was used instead of resin composition (X-1), and each was evaluated.
[0085] (Example 3: Resin composition for tow prepreg (X-3)) A resin composition for tow prepreg (X-3) was prepared in the same manner as in Example 1, except that 13.0 parts by mass of FA-326M (manufactured by Resonaq Corporation, methacrylate of ethylene oxide adduct of bisphenol A, molecular weight 628, equivalent weight of (meth)acrylic group 314, weight loss rate of less than 0.1% when heated at 50°C for 1 hour under normal pressure) was used as the (meth)acrylate monomer (B-2d) in place of the above (meth)acrylate monomer (B-2b). Resin molded plates A and B and tow prepreg (3) were prepared in the same manner as in Example 1, except that resin composition (X-3) was used in place of the above resin composition (X-1), and each was evaluated.
[0086] (Example 4: Resin composition for tow prepreg (X-4)) Resin composition (X-4) for tow prepreg was prepared in the same manner as in Example 1, except that the amount of the above resin mixture (AM-1) used was changed to 64.86 parts by mass, the amount of the above (meth)acrylate monomer (B-1) used was changed to 30.2 parts by mass, the amount of the above (meth)acrylate monomer (B-2a) used was changed to 5.0 parts by mass, and the above (meth)acrylate monomer (B-2b) was not used at all. Resin molded plates A and B and tow prepreg (4) were prepared in the same manner as in Example 1, except that resin composition (X-4) was used instead of resin composition (X-1), and each was evaluated.
[0087] (Example 5: Resin composition for tow prepreg (X-5)) A resin composition for tow prepreg (X-5) was prepared in the same manner as in Example 1, except that the amount of the above resin mixture (AM-1) used was changed to 52.05 parts by mass, the amount of dicyclopentanyl methacrylate (B-1) used was changed to 41.9 parts by mass, and the above (meth)acrylate monomer (B-2b) was not used at all. Resin molded plates A and B and tow prepreg (5) were prepared in the same manner as in Example 1, except that resin composition (X-5) was used instead of resin composition (X-1), and each was evaluated.
[0088] (Comparative Example 1: Resin composition for tow prepreg (RX-1)) A resin composition for tow prepreg (RX-1) was prepared in the same manner as in Example 1, except that the amount of the above resin mixture (AM-1) used was changed to 77.08 parts by mass, the amount of dicyclopentanyl methacrylate (B-1) used was changed to 17.0 parts by mass, the amount of the above (meth)acrylate monomer (B-2a) used was changed to 6.0 parts by mass, and the above (meth)acrylate monomer (B-2b) was not used at all. Resin molded plates A and B and tow prepreg (R1) were prepared in the same manner as in Example 1, except that the obtained resin composition (RX-1) was used, and each was evaluated.
[0089] (Comparative Example 2: Preparation and Evaluation of Resin Composition for Tow Prepreg (RX-2)) A resin composition for tow prepreg (RX-2) was prepared in the same manner as in Example 1, except that the amount of the above resin mixture (AM-1) used was changed to 45.45 parts by mass, the amount of dicyclopentanyl methacrylate (B-1) used was changed to 44.6 parts by mass, the amount of the above (meth)acrylate monomer (B-2a) used was changed to 10.0 parts by mass, and the above (meth)acrylate monomer (B-2b) was not used at all. A resin composition for tow prepreg (RX-2) was prepared in the same manner as in Example 1, except that the obtained resin composition (RX-2) was used, and a resin molded plate A, B and a tow prepreg (R2) were produced and evaluated.
[0090] (Comparative Example 3: Resin composition for tow prepreg (RX-3)) A resin composition for tow prepreg (RX-3) was prepared in the same manner as in Example 1, except that 24.5 parts by mass of methyl methacrylate (molecular weight 100, weight loss rate 100% when heated at atmospheric pressure, 50°C, for 1 hour) was used as a (meth)acrylate monomer (B-2e) instead of dicyclopentanyl methacrylate (B-1). Resin molded plates A and B and tow prepreg (R2) were prepared in the same manner as in Example 1, except that the obtained resin composition (RX-3) was used, and each was evaluated.
[0091] (Comparative Example 4: Resin composition for tow prepreg (RX-4)) A resin composition for tow prepreg (RX-4) was prepared in the same manner as in Example 1, except that the amount of dicyclopentanyl methacrylate (B-1) used was changed to 19.0 parts by mass and the amount of (meth)acrylate monomer (B-2b) used was changed to 18.0 parts by mass. Resin molded plates A and B and 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 was evaluated.
[0092] (Example 6: Resin composition for sheet prepreg (S-1)) [Preparation of resin intermediate composition (SM-1)] 21.0 parts by mass of dicyclopentanyl methacrylate (B-1), 2.6 parts by mass of the above (meth)acrylate monomer (B-2a), 6.5 parts by mass of the above (meth)acrylate monomer (B-2b), 61.86 parts by mass of the resin mixture (AM-2) obtained in Synthesis Example 2, and 0.02 parts by mass of parabenzoquinone were placed in a stainless steel container and heated in a 50°C drying oven for 2 hours. After confirming that the mixture was dissolved, it was stirred and mixed. Next, 2.0 parts by mass of polymerization initiator (C-1) ("Trigonox 122-C80" manufactured by Kayaku Nurion Co., Ltd., an organic peroxide) was mixed in to prepare a resin intermediate composition (SM-1).
[0093] [Preparation of resin composition (S-1) for sheet prepreg] A resin composition for sheet prepreg (S-1) was prepared by mixing 93.98 parts by mass of the obtained resin intermediate composition (SM-1) with 8.1 parts by mass of the post-addition polyisocyanate mixture (a1-1) obtained in Synthesis Example 3 at room temperature. Upon mixing, the urethane (meth)acrylate resin intermediate (A'-2) contained in the resin intermediate composition (SM-1) reacted with the post-addition polyisocyanate mixture (a1-1) to produce urethane (meth)acrylate resin (A-2).
[0094] [Fabrication of resin molded plate A and evaluation of impact resistance] A 6 mm thick resin molded plate A was prepared in the same manner as in Example 1, except that resin composition (S-1) was used instead of resin composition (X-1), and its impact resistance was evaluated.
[0095] [Evaluation of the heat resistance of cured resin sheet B, part 2] A 4 mm thick resin molded plate B was prepared in the same manner as in Example 1, except that the above resin composition (S-1) was used instead of the above resin composition (X-1), and its heat resistance was evaluated.
[0096] [Preparation of sheet prepreg] Using the obtained resin composition (S-1) and the above-mentioned reinforcing fiber bundles, a sheet prepreg was prepared using a prepreg manufacturing apparatus equipped with a creel, fiber defibration device, resin coater, impregnation roll, nip roll, winder, and tension control machine, as follows: First, the reinforcing fiber bundles of high-strength carbon fiber T700SC-12K (manufactured by Toray Industries, Inc.) were defibrated using a fiber defibration device, and then the multiple defibrated reinforcing fiber bundles were aligned in one direction to obtain a unit weight of 150 g / m². 2 The temperature was adjusted to the following. Next, the above resin composition (S-1), adjusted to a temperature of 30°C, was applied to one side of the release-treated PET film, at a unit weight of 58 g / m². 2 The PET film was coated in such a manner. The resin surface of the PET film coated with resin composition (S-1) was brought into contact with one side of a reinforcing fiber bundle aligned in one direction, and a release-treated PET film without resin coating was brought into contact with the opposite side of the reinforcing fiber bundle. The PET film was then passed through an impregnation roll and a nip roll to impregnate the reinforcing fiber bundle with resin composition (S-1), thereby producing a sheet prepreg (S1). The sheet prepreg (S1) had a resin composition (S-1) content of 27.8% by mass. The manufacturing apparatus was operated at 15 m / min for 0.5 hours. The obtained sheet prepreg (S1) was wound onto a 12-inch paper tube, packaged in an oxygen barrier film, placed in an oxygen barrier film bag, purged with nitrogen, sealed, and left to stand at room temperature.
[0097] [Evaluation of resin impregnation properties of sheet prepregs] The obtained sheet prepreg (S1) was removed from the bag seven days after production, and four 1m long sheet prepreg (S1) pieces were obtained by cutting 1m long pieces every 100m. The resin impregnation properties of each sheet prepreg (S1) were evaluated by visual observation. ○: The resin is uniformly impregnated on both sides of the reinforcing fiber bundle. △: A small amount of resin-unimpregnated fibers are present on both sides of the reinforcing fiber bundle. ×: Both sides of the reinforcing fiber bundle are not homogeneous, and there are many fibers that are not impregnated with resin.
[0098] [Evaluation of the mesh opening condition of sheet prepreg] The obtained 1m long sheet prepreg (S1) was placed on a light box, and the mesh opening state was evaluated by visual observation. Mesh opening refers to the gaps formed between adjacent reinforcing fibers when viewed from a planar direction. Mesh opening occurs when the reinforcing fibers move from their original positions while the sheet prepreg is stored. ○: There are no gaps throughout the entire sheet, or if there are gaps, their length is less than 10 mm and their width is less than 1 mm. △: There are openings with a length of 10mm or more but less than 20mm and a width of less than 1mm. ×: There are openings that are 20mm or longer in length and 1mm or wider.
[0099] (Example 7: Resin composition for sheet prepreg (S-2)) Resin intermediate composition (SM-2) was prepared in the same manner as in Example 6, except that the amount of dicyclopentanyl methacrylate (B-1) used was changed to 23.6 parts by mass, the (meth)acrylate monomer (B-2a) was not used at all, and 6.5 parts by mass of (meth)acrylate monomer (B-2c) was used in place of the (meth)acrylate monomer (B-2b). Subsequently, a resin composition for sheet prepreg (S-2) was prepared in the same manner as in Example 6, except that the obtained resin intermediate composition (SM-2) was used. Resin molded plates A and B and sheet prepreg (S2) were produced in the same manner as in Example 6, except that the obtained resin composition (S-2) was used, and each was evaluated.
[0100] (Example 8: Resin composition for sheet prepreg (S-3)) Resin intermediate composition (SM-3) was prepared in the same manner as in Example 6, except that the amount of dicyclopentanyl methacrylate (B-1) used was changed to 23.6 parts by mass, (meth)acrylate monomer (B-2a) was not used at all, and 6.5 parts by mass of (meth)acrylate monomer (B-2d) was used in place of (meth)acrylate monomer (B-2b). Subsequently, a resin composition for sheet prepreg (S-3) was prepared in the same manner as in Example 6, except that the obtained resin intermediate composition (SM-3) was used. Resin molded plates A and B and sheet prepreg (S3) were produced in the same manner as in Example 6, except that the obtained resin composition (S-3) was used, and each was evaluated.
[0101] (Example 9: Resin composition for sheet prepreg (S-4)) A resin intermediate composition (SM-4) was prepared in the same manner as in Example 6, except that the amount of dicyclopentanyl methacrylate (B-1) used was changed to 23.6 parts by mass, (meth)acrylate monomer (B-2a) was not used, and 3.0 parts by mass of (meth)acrylate monomer (B-2c) was used instead of (meth)acrylate monomer (B-2b), and the amount of the resin mixture (AM-2) used was changed to 64.96 parts by mass.
[0102] Next, a resin composition for sheet prepreg (S-4) was prepared by following the same procedure as in Example 6, except that 93.58 parts by mass of the resin intermediate composition (SM-4) obtained in this example was used, and the amount of polyisocyanate mixture (a1-1) used for post-addition was changed to 8.5 parts by mass. Resin molded plates A and B and a sheet prepreg (S4) were produced by following the same procedure as in Example 6, except that the obtained resin composition (S-4) was used, and each was evaluated.
[0103] (Example 10: Resin composition for sheet prepreg (S-5)) Resin intermediate composition (SM-5) was prepared in the same manner as in Example 6, except that the amount of dicyclopentanyl methacrylate (B-1) used was changed to 30.4 parts by mass, (meth)acrylate monomer (B-2a) was not used at all, 10.0 parts by mass of (meth)acrylate monomer (B-2c) was used in place of (meth)acrylate monomer (B-2b), and the amount of the resin mixture (AM-2) used was changed to 52.75 parts by mass.
[0104] Next, a resin composition for sheet prepreg (S-5) was prepared by following the same procedure as in Example 6, except that 95.17 parts by mass of the resin intermediate composition (SM-5) obtained in this example was used, and the amount of polyisocyanate mixture (a1-1) used for post-addition was changed to 6.9 parts by mass. Resin molded plates A and B and a sheet prepreg (S5) were produced by following the same procedure as in Example 6, except that the obtained resin composition (S-5) was used, and each was evaluated.
[0105] (Comparative Example 5: Resin composition for sheet prepreg (RS-1)) A resin intermediate composition (RSM-1) was prepared in the same manner as in Example 6, except that the amount of dicyclopentanyl methacrylate (B-1) used was changed to 17.1 parts by mass, (meth)acrylate monomer (B-2b) was not used at all, and the amount of the resin mixture (AM-2) used was changed to 71.07 parts by mass.
[0106] Next, a resin composition for sheet prepreg (RS-1) was prepared by following the same procedure as in Example 6, except that 92.79 parts by mass of the resin intermediate composition (RSM-1) obtained in this comparative example was used, and the amount of the post-addition polyisocyanate mixture (a1-1) used was changed to 9.3 parts by mass. Resin molded plates A and B and a sheet prepreg (RS1) were prepared by following the same procedure as in Example 6, except that the obtained resin composition (RS-1) was used, and each was evaluated.
[0107] (Comparative Example 6: Preparation and Evaluation of Resin Composition for Sheet Prepreg (RS-2)) A resin intermediate composition (RSM-2) was prepared in the same manner as in Example 6, except that the amount of dicyclopentanyl methacrylate (B-1) used was changed to 45.0 parts by mass, (meth)acrylate monomer (B-2b) was not used at all, and 10.0 parts by mass of (meth)acrylate monomer (B-2c) was used in place of (meth)acrylate monomer (B-2b), and the amount of the resin mixture (AM-2) used was changed to 39.84 parts by mass. Subsequently, a resin composition for sheet prepreg (RS-2) was prepared in the same manner as in Example 6, except that 96.86 parts by mass of the resin intermediate composition (RSM-2) obtained in this comparative example was used, and the amount of the polyisocyanate mixture for post-addition (a1-1) was changed to 5.2 parts by mass. Resin molded plates A and B and a sheet prepreg (RS2) were prepared in the same manner as in Example 6, except that the obtained resin composition (RS-2) was used, and each was evaluated.
[0108] Table 1 shows the evaluation results for the resin compositions (X-1) to (X-5) and (RX-1) to (RX-4) for tow prepregs in Examples 1 to 5 and Comparative Examples 1 to 4. Table 2 shows the evaluation results for the resin compositions (S-1) to (S-5) and (RS-1) to (RS-2) for sheet prepregs in Examples 6 to 10 and Comparative Examples 5 to 6. In the table, "(A)" refers to urethane (meth)acrylate resins (A-1) and (A-2). In the table, "(B)" refers to dicyclopentanyl methacrylate (B-1) and (meth)acrylate monomers (B-2a) to (B-2e).
[0109] [Table 1]
[0110] [Table 2]
[0111] As shown in Table 1, the resin compositions (X-1) to (X-5) for tow prepregs in Examples 1 to 5 have excellent impregnation properties into reinforcing fibers, and the tow prepregs (1) to (5) made from the resin compositions (X-1) to (X-5) have excellent unwinding properties. Furthermore, since the resin molded sheets made from the resin compositions (X-1) to (X-5) all possess excellent fracture toughness and heat resistance, it is possible to produce molded articles with excellent fracture toughness and heat resistance using tow prepregs (1) to (5) made with the resin compositions (X-1) to (X-5). Furthermore, since the resin compositions (X-1) to (X-5) are compounds with low volatility, each (meth)acrylate monomer (B) exhibiting a weight loss rate of less than 3% when heated at atmospheric pressure at 50°C for 60 minutes, volatilization during the production of molded articles from tow prepregs (1) to (5) can be suppressed, ensuring the quality stability of the molded articles.
[0112] In contrast, the resin compositions (RX-1) and (RX-3) for tow prepregs in Comparative Examples 1 and 3 have poor impregnation properties into reinforcing fibers, and the tow prepregs (R1) and (R3) produced from these resin compositions (RX-1) and (RX-3) also have poor unwinding properties. Furthermore, the resin molded sheets produced from these resin compositions (RX-1) and (RX-3) have poor heat resistance, so the tow prepregs (R1) and (R3) produced using these resin compositions (RX-1) and (RX-3) cannot produce molded articles with excellent heat resistance. The resin molded sheets produced from the resin compositions (RX-2) and (R-4) for tow prepregs in Comparative Examples 2 and 4 have poor impact resistance, so the tow prepregs (R2) and (R4) produced using these resin compositions (RX-2) and (R-4) cannot produce molded articles with excellent impact resistance.
[0113] As shown in Table 2, the resin compositions (S-1) to (S-5) for sheet prepregs in Examples 6 to 10 have excellent impregnation properties into reinforcing fibers, and the sheet prepregs (S1) to (S5) made from these resin compositions (S-1) to (S-5) have excellent unwinding properties. Furthermore, since the resin molded plates made from these resin compositions (S-1) to (S-5) all possess excellent fracture toughness and heat resistance, it is possible to produce molded articles with excellent fracture toughness and heat resistance using the sheet prepregs (S1) to (S-5) made with these resin compositions (S-1) to (S-5). Furthermore, since the resin compositions (S-1) to (S-5) are compounds with low volatility, each (meth)acrylate monomer (B) exhibiting a weight loss rate of less than 3% when heated at atmospheric pressure, 50°C, and 60 minutes, volatilization during the production of molded articles from the sheet prepregs (S1) to (S5) can be suppressed, ensuring the quality stability of the molded articles.
[0114] In contrast, the resin molded plate made from the resin composition for sheet prepreg (RS-1) of Comparative Example 4 has poor heat resistance, and therefore, the sheet prepreg (RS1) made using the resin composition (RS-1) cannot produce a molded article with excellent heat resistance. The resin molded plate made from the resin composition for sheet prepreg (RS-2) of Comparative Example 5 has poor impact resistance, and therefore, the sheet prepreg (RS2) made using the resin composition (RS-2) cannot produce a molded article with excellent impact resistance.
Claims
1. A resin composition for prepregs containing a urethane (meth)acrylate resin (A), a (meth)acrylate monomer (B), and a polymerization initiator (C), The urethane (meth)acrylate resin (A) is a reaction product of polyisocyanate (a1), polyol having an aromatic skeleton (a2), and hydroxyalkyl (meth)acrylate (a3). The (meth)acrylate monomer (B) contains at least dicyclopentanyl methacrylate, and the content of dicyclopentanyl methacrylate is 50% by mass or more of the total content of the (meth)acrylate monomer (B). A resin composition for prepregs in which the total content of the (meth)acrylate monomer (B) is 25% by mass or more and 50% by mass or less with respect to the total mass of the urethane (meth)acrylate (A) and the (meth)acrylate monomer (B).
2. The resin composition for prepreg according to claim 1, further comprising a (meth)acrylate monomer (B) having a weight loss rate of less than 3% when heated at atmospheric pressure, 50°C, and for 1 hour.
3. The resin composition for prepregs according to claim 1 or 2, further comprising a (meth)acrylate monomer (B) having an aromatic skeleton and / or an alicyclic skeleton in the molecule and having one or two (meth)acrylate groups.
4. The resin composition for prepreg according to claim 1 or 2, further comprising a (meth)acrylate monomer (B) having a (meth)acrylate group equivalent of 150 or more and 400 or less.
5. The resin composition for prepregs according to claim 1 or claim 2, wherein the polyol (a2) is an oxyalkylene adduct of a bisphenol compound.
6. A prepreg comprising the prepreg resin composition according to claim 1 or claim 2 and reinforcing fibers, wherein the prepreg resin composition is impregnated into the reinforcing fibers.