TW202506846A - Prepreg and molded products - Google Patents

Abstract

The present invention addresses the problem of providing: a prepreg capable of achieving excellent flame retardancy even without containing a halogen-containing compound; and a molded article thereof. A prepreg according to the present invention contains a urethane (meth)acrylate (A), an ethylenically unsaturated monomer (B) other than the urethane (meth)acrylate (A), a polymerization initiator (C), a reinforcing fiber (D), and a flame retardant (E). The urethane (meth)acrylate (A) is a reaction product of a polyisocyanate (a1) and a polyol (a2) having an ethylenically unsaturated group and an aromatic skeleton, and/or a reaction product of a polyisocyanate (a1), a polyol (a3) having an aromatic skeleton without having an ethylenically unsaturated group, and a hydroxyalkyl (meth)acrylate (a4), and the flame retardant (E) contains at least one halogen-free phosphorus compound.

Description

Prepreg and molded products

The present invention relates to a prepreg and a molded product thereof.

Fiber-reinforced resin composites reinforced with reinforcing fibers such as carbon fibers and glass fibers have attracted much attention for their light weight and excellent heat resistance and mechanical strength, and are being used in a variety of structural applications, such as automobile and aircraft frames and various components. As a molding method for the fiber-reinforced resin composite, for example, a method is used in which an intermediate material called a prepreg impregnated with a thermosetting resin in the reinforcing fibers is used, and the prepreg is hardened and molded by autoclave molding or press molding.

Prepregs are required to be flame retardant depending on their intended use. For example, they may be used in construction or in battery boxes for automobiles. In particular, lithium-ion secondary batteries, which are often used as batteries for electric vehicles, may catch fire because they contain organic solvents. In order to ensure safety in use, prepregs used to form battery boxes for housing the lithium-ion secondary batteries are required to meet the flame retardancy standards specified by Underwriters Laboratories, Inc. (UL).

Previously, as a flame-retardant prepreg, a prepreg containing a halogen-containing compound such as brominated phenol as a flame retardant is known (for example, refer to Patent Document 1). However, the halogen-containing compound has a disadvantageous condition that causes concern about the impact on the environment. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Publication No. 2009-521666

[The problem that the invention wants to solve]

The problem to be solved by the present invention is to provide a prepreg and a molded product thereof, which can achieve excellent flame retardancy even without containing a halogen-containing compound. [Means for solving the problem]

The inventors of the present invention have found that a prepreg containing a specific urethane (meth)acrylate, a specific ethylenically unsaturated monomer, a polymerization initiator, a reinforcing fiber and a specific flame retardant solves the above-mentioned problems, thereby completing the present invention.

That is, it is related to a prepreg, which is characterized by containing: urethane (meth) acrylate (A), ethylenically unsaturated monomers (B) other than the urethane (meth) acrylate (A), a polymerization initiator (C), a reinforcing fiber (D), and a flame retardant (E), wherein the urethane (meth) acrylate (A) is a reaction product of polyisocyanate (a1) and a polyol (a2) having an ethylenically unsaturated group and an aromatic skeleton, and/or a reaction product of polyisocyanate (a1) and a polyol (a3) having no ethylenically unsaturated group but an aromatic skeleton and a hydroxyalkyl (meth) acrylate (a4), and the flame retardant (E) contains one or more halogen-free phosphorus compounds. [Effect of the invention]

Even if the prepreg of the present invention does not contain a halogen-containing compound, the molded product obtained from the prepreg can achieve excellent flame retardancy.

The prepreg of the present invention is characterized in that it contains: urethane (meth) acrylate (A), ethylenically unsaturated monomers (B) other than the urethane (meth) acrylate (A), a polymerization initiator (C), a reinforcing fiber (D), and a flame retardant (E), wherein the urethane (meth) acrylate (A) is a reaction product of polyisocyanate (a1) and a polyol (a2) having an ethylenically unsaturated group and an aromatic skeleton, and/or a reaction product of polyisocyanate (a1) and a polyol (a3) having no ethylenically unsaturated group but an aromatic skeleton and a hydroxyalkyl (meth) acrylate (a4), and the flame retardant (E) contains one or more halogen-free phosphorus compounds.

In order to further improve the heat resistance of the molded article, the polyisocyanate (a1) preferably includes a polyisocyanate having a cyclic skeleton. These polyisocyanates (a1) may be used alone or in combination of two or more.

Examples of the polyisocyanate (a1) include 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, carbodiimide modified products of 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, urate modified products of diphenylmethane diisocyanate, biuret modified products, urethane imide modified products, polyol modified products modified with a polyol having a number average molecular weight of 1,000 or less such as diethylene glycol or dipropylene glycol, toluene diisocyanate (tolylene diisocyanate), poly ... diisocyanate (TDI), tolidine diisocyanate, xylene diisocyanate, 1,5-naphthalene diisocyanate, tetramethylxylene diisocyanate and other aromatic polyisocyanates; isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, norbornene diisocyanate and other aliphatic polyisocyanates; hexamethylene diisocyanate, urate modified product of hexamethylene diisocyanate, biuret modified product, adduct, dimer acid diisocyanate and other aliphatic polyisocyanates, etc. Among these, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, carbodiimide modified 4,4'-diphenylmethane diisocyanate, and polymethylene polyphenyl polyisocyanate are preferred in terms of further improving the heat resistance of the molded article. These polyisocyanates (a1) may be used alone or in combination of two or more.

The polyol (a2) has an ethylenically unsaturated group and an aromatic skeleton. In terms of further improving heat resistance, a polyfunctional epoxy (meth) acrylate is preferred. For example, it is a reaction product of a bisphenol-type epoxy resin such as bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, bisphenol fluorene-type epoxy resin, biscresol fluorene-type epoxy resin, a phenol novolac-type epoxy resin, a cresol novolac-type epoxy resin, and (meth) acrylic acid. Preferably, it is obtained by reacting an epoxy resin having an epoxy equivalent in the range of 180 to 500 with (meth) acrylic acid. The number of functional groups is preferably 1.5 to 3.0 in terms of the balance between heat resistance and strength properties.

The polyol (a3) does not have an ethylenically unsaturated group but has an aromatic skeleton. Examples thereof include oxirane adducts of bisphenol compounds such as oxirane adducts of bisphenol A, oxirane adducts of bisphenol S, and oxirane adducts of bisphenol F; oxirane adducts of dihydroxybenzene compounds such as 1,3-bis(2-hydroxyethoxy)benzene and 1,4-bis(2-hydroxyethoxy)benzene; oxirane adducts of biphenol compounds such as 2'-[(1,1'-biphenyl-4,4'-diyl)bis(oxy)]bisethanol; oxirane adducts of dihydroxynaphthalene compounds, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, and the like. Among these, alkylene oxide adducts of bisphenol compounds are preferred from the viewpoint of the balance of compatibility, heat resistance, water resistance and strength properties, and ethylene oxide adducts of bisphenol compounds are more preferred, with the average addition molar number being 2 mol to 10 mol.

Examples of the hydroxyalkyl (meth)acrylate (a4) 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 in terms of the balance of strength and physical properties. These hydroxyalkyl (meth)acrylates (a4) may be used alone or in combination of two or more.

In addition, other polyols other than the polyols (a2) to (a3) may be used as raw materials of the urethane (meth)acrylate (A) as necessary. As other polyols, polyester polyols, acrylic polyols, polyether polyols, polycarbonate polyols, polyalkylene polyols, etc. may be used.

In order to further improve heat resistance and curability, the molar ratio (a3/a4) of the polyol (a3) to the hydroxyalkyl (meth)acrylate (a4) is preferably 60/40 to 20/80, more preferably 50/50 to 30/70.

In terms of the balance between heat resistance and strength properties, the molar ratio (NCO/OH) of the isocyanate group (NCO) of the isocyanate compound serving as the raw material of the urethane (meth)acrylate (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.

Examples of the ethylenically unsaturated monomer (B) include dimethacrylate of ethylene oxide adduct of bisphenol A, tricyclodecanedimethanol dimethacrylate, 1,12-dodecanediol dimethacrylate, hydrogenated bisphenol A dimethacrylate, polytetramethylene glycol dimethacrylate, 9,9-bis[4-(2-methacryloyloxyethoxy)phenyl]fluorene, dimethacrylate of ethylene oxide adduct of isosorbide, dimethacrylate of ethylene oxide adduct of hydrogenated bisphenol A, trimethacrylate of ethylene oxide adduct of trihydroxymethylpropane, tetramethacrylate of ethylene oxide adduct of pentaerythritol, hexamethacrylate of ethylene oxide adduct of dipentaerythritol, and the like. In terms of the balance between curability, heat resistance and strength, the molecular weight is preferably 320 to 2,000, and the (meth)acrylic acid group equivalent is preferably 150 to 1,000, more preferably 150 to 500. Similarly, in terms of the balance between curability, heat resistance and strength, the number of functional groups is preferably 2 to 4, more preferably 2.

In terms of preventing contamination of the working environment and further improving the balance between prepreg handling properties, molded product quality, and productivity, the content of the ethylenic unsaturated monomer (B) in the total of the urethane (meth)acrylate (A) and the ethylenic unsaturated monomer (B) (hereinafter referred to as "content (B)") is preferably 5% by mass to 50% by mass, and more preferably 10% by mass to 40% by mass.

The polymerization initiator (C) is not particularly limited, but is preferably an organic peroxide, for example, diacyl peroxide compounds, peroxyester compounds, hydroperoxide compounds, ketone peroxide compounds, alkyl perester compounds, percarbonate compounds, peroxyketal compounds, etc., which can be appropriately selected according to the molding conditions. Furthermore, these polymerization initiators (C) can be used alone or in combination of two or more.

In addition, among these, 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 it can be cured in a short time (within 5 minutes) by heating, so it is preferred, and by using it in the prepreg of the present invention, the curability and molding properties are more excellent. 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. According to the molding conditions, select and use the most suitable organic peroxide.

The amount of the polymerization initiator (C) added is preferably in the range of 0.5 to 3 parts by mass based on 100 parts by mass of the total of the urethane (meth)acrylate (A) and the ethylenically unsaturated monomer (B) in terms of excellent curing characteristics and storage stability.

Examples of the reinforcing fiber (D) include organic fibers such as carbon fiber, glass fiber, silicon carbide fiber, alumina fiber, boron fiber, metal fiber, aromatic polyamide fiber, vinyl fiber, and tetoron fiber. In terms of obtaining a molded product with higher strength and higher elasticity, carbon fiber or glass fiber is preferred, and carbon fiber is more preferred. These reinforcing fibers (D) may be used alone or in combination of two or more.

As the carbon fiber, various types of carbon fibers such as polyacrylonitrile-based, asphalt-based, and rayon-based can be used. Among these, polyacrylonitrile-based carbon fibers are preferred because high-strength carbon fibers can be easily obtained.

The shape of the reinforcing fiber (D) is not particularly limited, and examples thereof include: a reinforcing fiber bundle obtained by bundling reinforcing fiber filaments, or a unidirectional material obtained by straightening a reinforcing fiber bundle in one direction, a woven fabric or short reinforcing fibers, or a non-woven fabric or paper containing short reinforcing fibers. By using a unidirectional material as the reinforcing fiber and laminating and forming it, high mechanical properties can be obtained, so it is preferred.

When using short reinforced fibers, it is preferable to use carbon fibers cut into 2.5 mm to 50 mm in terms of further improving the fluidity in the mold during molding and the appearance of the molded product.

In the case of fabrics, there can be mentioned sheets in which fiber bundles are aligned in one direction, such as plain weave, twill weave, satin weave or non-woven weave, or sewed sheets in which sheets stacked at different angles are sewed tightly.

The weight per unit area of the reinforcing fiber (weight of fiber per 1 m ² ) is not particularly limited, but is preferably 10 g/m ² to 650 g/m ² . If the weight per unit area is 10 g/m ² or more, the fiber width is less uneven and the mechanical properties are good, which is preferred. If the weight per unit area is 650 g/m ² or less, the resin impregnation is good, which is preferred. The weight per unit area is further preferably 50 g/m ² to 500 g/m ² , and particularly preferably 50 g/m ² to 300 g/m ² .

In order to further improve the mechanical strength of the obtained molded product, the content of the reinforcing fiber (D) in the prepreg of the present invention is preferably in the range of 20 mass % to 85 mass %, more preferably in the range of 40 mass % to 80 mass %.

The flame retardant (E) contains one or more halogen-free phosphorus compounds. The so-called halogen-free phosphorus compound refers to a compound that does not contain halogens but contains phosphorus. The prepreg of the present invention can obtain excellent flame retardancy in the molded product obtained from the prepreg by containing the flame retardant (E). In addition, since the flame retardant (E) does not contain halogens (halogen-free), the impact on the environment caused by the release of halogens can be prevented during the manufacturing process of the prepreg or the molded product. Here, in the case of using a compound that does not contain phosphorus on a halogen-free basis as the flame retardant, the molded product cannot obtain excellent flame retardancy.

Examples of the halogen-free phosphorus compound include red phosphorus, phosphonates, ammonium polyphosphates, phosphates, aromatic phosphates, aromatic condensed phosphates, phosphazenes, etc. Examples of commercially available products include Nova Excel 140, Nonnen 73, FCP-770, DAIGUARD-880, TPP, TCP, CDP, PX-110, CR-733S, CR-741, PX-200, DAIGUARD-580, DAIGUARD-850, Rabitle FP-110, and Rabitle FP-100.

When the prepreg is heated, free radicals generated by the decomposition of the polymerization initiator (C) are added to the ethylenically unsaturated monomer (B), thereby causing a polymerization reaction. The polymerization heat generated by the polymerization reaction can shorten the time until the desired peak temperature is reached in the prepreg being heated, and the prepreg can obtain rapid curing properties. However, in the case of a compound containing active hydrogen in the halogen-free phosphorus compound, the active hydrogen deactivates the free radicals and hinders the polymerization reaction. As a result, the time until the desired peak temperature is reached in the prepreg being heated is delayed, or the peak temperature may not be reached. Therefore, it is preferable to use a compound containing no active hydrogen as the halogen-free phosphorus compound.

On the other hand, even if the halogen-free phosphorus compound contains active hydrogen, in the case of a salt compound, since the solubility of the salt in the resin component in the prepreg is low, it is difficult for the active hydrogen to deactivate the free radicals, and thus the interference of the active hydrogen on the polymerization reaction can be suppressed. As a result, it is possible to prevent the time delay until the desired peak temperature is reached in the prepreg being heated, or to prevent the peak temperature from being reached, and the prepreg can obtain rapid curing properties. That is, as the halogen-free phosphorus compound, it is preferred to use a salt compound. The salt compound may contain active hydrogen or may not contain active hydrogen. Moreover, if flame retardancy, ease of acquisition, price, etc. are taken into consideration, ammonium phosphate is more preferred as the halogen-free salt compound.

That is, the halogen-free phosphorus compound is preferably a phosphorus compound containing no active hydrogen or ammonium phosphate. The ammonium phosphate may contain active hydrogen or may not contain active hydrogen. However, in this specification, the phosphorus compound containing no active hydrogen does not include ammonium phosphate containing no active hydrogen.

Examples of the phosphorus compound not containing active hydrogen include ammonium polyphosphate, phosphoric acid, phosphate, polyphosphoric acid, polyphosphate, etc. Examples of commercially available products include FCP-770, FCP-790, phosphoric acid, sodium phosphate, polyphosphoric acid, sodium polyphosphate, etc.

Commercially available products of the ammonium phosphate include FCP-770, FCP-790, and the like.

As components of the prepreg of the present invention, components other than the above components may be used, for example, it may contain: thermosetting resin, thermoplastic resin, polymerization inhibitor, curing accelerator, filler, low shrinkage agent, mold release agent, thickener, viscosity reducer, pigment, antioxidant, plasticizer, antibacterial agent, ultraviolet stabilizer, reinforcing agent, photocuring agent, etc.

Examples of the thermosetting resin include vinyl ester resin, unsaturated polyester resin, phenol resin, melamine resin, furan resin, dimaleimide resin, etc. These thermosetting resins may be used alone or in combination of two or more.

Examples of the thermoplastic resin include polyamide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polycarbonate resin, polyurethane resin, polypropylene resin, polyethylene resin, polystyrene resin, acrylic resin, polybutadiene resin, polyisoprene resin, and those obtained by copolymerization or the like. Among these, polyamide resin and polyurethane resin are preferred in terms of their high effect of improving brittleness. In addition, these thermoplastic resins may be used alone or in combination of two or more. In addition, the thermoplastic resin may be added and used in the form of particles, or may be used after melt mixing. When a thermoplastic resin in a particle form is used, the particle size is preferably 30 μm or less, more preferably 5 μm to 20 μm, from the viewpoint of dispersibility in the fiber.

Examples of the polymerization inhibitor include hydroquinone, trimethylhydroquinone, p-tert-butylo-o-catechol, tert-butylhydroquinone, toluhydroquinone, p-benzoquinone, naphthoquinone, hydroquinone monomethyl ether, phenothiazine, copper cycloalkanoate, copper chloride, etc. These polymerization inhibitors may be used alone or in combination of two or more.

Examples of the hardening accelerator include metal soaps such as cobalt cycloalkanoate, cobalt octenate, vanadium octenate, copper cycloalkanoate, and barium cycloalkanoate; and metal chelate compounds such as vanadium acetoacetate, cobalt acetoacetate, and iron acetopyruvate. Examples of the amine include N,N-dimethylamino-p-benzaldehyde, N,N-dimethylaniline, N,N-diethylaniline, N,N-dimethyl-p-toluidine, N-ethyl-m-toluidine, triethanolamine, m-toluidine, diethylenetriamine, pyridine, phenylmorpholine, piperidine, and diethanolaniline. These hardening accelerators may be used alone or in combination of two or more.

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

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, iron powder, and the like.

As the organic compound, there are natural polysaccharide powders such as cellulose and chitin, or synthetic resin powders, etc. As the synthetic resin powder, there can be used: powders of organic substances including hard resins, soft rubbers, elastomers or polymers (copolymers), or particles having a multilayer structure such as a core-shell type. Specifically, there can be listed: acrylic particles, polyamide particles, particles including butadiene rubber and/or acrylic rubber, urethane rubber, silicone rubber, etc., polyimide resin powder, fluororesin powder, phenol resin powder, etc. These fillers can be used alone or in combination of two or more.

Examples of the release agent include zinc stearate, calcium stearate, wax, polyethylene wax, and carnauba wax. Preferably, wax, polyethylene wax, and carnauba wax are used. These release agents may be used alone or in combination of two or more.

Examples of the thickener include metal oxides or metal hydroxides such as magnesium oxide, magnesium hydroxide, calcium oxide, and calcium hydroxide, and acrylic resin particles, which can be appropriately selected according to the handling properties of the prepreg of the present invention. These thickeners can be used alone or in combination of two or more.

The prepreg of the present invention can be obtained, for example, by the following steps 1 and 2: the step 1: using a planetary mixer, a kneader or other known mixer to mix the polyisocyanate (a1), the polyol (a2) and/or the polyol (a3), the (meth)acrylate hydroxyalkyl ester (a4), the ethylenic unsaturated monomer (B), the polymerization initiator (C) and the flame retardant (E), the reinforcing fiber (D) is impregnated in a resin solution, and then the reinforcing fiber (D) is impregnated from the upper surface by using a demolding polyethylene terephthalate (PET) The step 2 is to place the sheet at room temperature to 50° C. to allow the isocyanate group of the polyisocyanate (a1) to react with the hydroxyl group of the polyol (a2) and/or the polyol (a3) and the hydroxyl alkyl (meth)acrylate (a4). In addition, in step 1, a resin solution obtained by partially reacting the polyisocyanate (a1), the polyol (a2) and/or the polyol (a3) and the hydroxyl alkyl (meth)acrylate (a4) may be used within a range that does not impair the impregnation property of the fiber.

The thickness of the prepreg of the present invention is preferably 0.02 mm to 1.0 mm. A thickness of 0.02 mm or more is preferred because lamination processing becomes easy, and a thickness of 1 mm or less is preferred because resin impregnation becomes good. Further preferably, it is 0.05 mm to 0.5 mm.

As a method for obtaining a molded product from the obtained prepreg, for example, the following method can be used: the mold release PET film is peeled off from the prepreg, 8 to 30 prepreg volume layers are then put into a mold preheated to 110°C to 160°C, the prepreg is molded by closing the mold using a compression molding machine, a molding pressure of 0.1 MPa to 10 MPa is maintained to harden the prepreg, and then the molded product is taken out to obtain a molded product.

The molded product obtained from the prepreg of the present invention has excellent bending strength, interlaminar shear strength, etc., and can therefore be suitably used in automobile components, railway vehicle components, aerospace components, ship components, housing equipment components, sports equipment components, light vehicle components, building and civil engineering components, frames of office automation (OA) machines, etc. [Example]

The present invention is described in more detail with the following specific examples. [Example 1]

(1) Preparation of prepreg resin composition 29.0 parts by weight of a mixture of polymethylene polyphenyl polyisocyanate and diphenylmethane diisocyanate ("Millionate MR-200" manufactured by Tosoh Co., Ltd.), 9.9 parts by weight of 4,4'-diphenylmethane diisocyanate (hereinafter referred to as "MDI"), 26.9 parts by weight of hydroxyethyl methacrylate (hereinafter referred to as "HEMA"), and Newpol BPE-20 (manufactured by Sanyo Chemical Co., Ltd.: ethylene oxide (EO) adduct of bisphenol A, hydroxyl equivalent: 164 g/eq) 6.3 parts by mass, Newpol BPE-40 (manufactured by Sanyo Chemical Co., Ltd.: EO adduct of bisphenol A, hydroxyl equivalent: 204 g/eq) 8.9 parts by mass, PEG-300 (manufactured by Sanyo Chemical Co., Ltd.: polyethylene glycol, hydroxyl equivalent: 150 g/eq) 0.7 parts by mass, the thermoplastic resin described below 6.3 parts by mass, MIRAMER M-245 (manufactured by Miwon Specialty Chemical Co., Ltd.: difunctional methacrylate monomer) as a polymerizable monomer 12.0 parts by mass, a polymerization initiator (KAYAKU Trigonox 122-C80 manufactured by NOURYON Co., Ltd., 1.0 parts by weight of organic peroxide, and 30.0 parts by weight of Fire Cut P-770 (ammonium polyphosphate system manufactured by Suzuyu Chemical Co., Ltd.) as a halogen-free flame retardant were mixed to obtain a prepreg resin composition (1). The ammonium polyphosphate contained in the halogen-free flame retardant is a halogen-free ammonium phosphate salt containing active hydrogen. The thermoplastic resin is synthesized by mixing 71 parts by mass of PTMG1000 (manufactured by Mitsubishi Chemical Co., Ltd.: polytetramethylene ether glycol), 3 parts by mass of 1,4-butanediol (hereinafter referred to as "1,4-BG"), and 26 parts by mass of MDI, casting them into a vat, and reacting them at 90°C for 24 hours. The weight average molecular weight of the obtained thermoplastic resin is 50,000.

(2) Preparation of prepreg The obtained prepreg was coated with a resin composition on one side of a release PET film, and then impregnated with carbon fiber ("TRK979PQRW" manufactured by Mitsubishi Chemical Co., Ltd.) by hand lay-up to a carbon fiber volume content of 55%. After covering with the same release PET film, the prepreg was aged at 45°C for 24 hours to prepare a prepreg (1).

(3) Evaluation of prepreg The obtained prepreg was cut and layered to obtain a test piece A with a length of 50 mm × a width of 50 mm × a thickness of 2.2 mm. The obtained test piece A was subjected to a rapid curing evaluation test. A thermocouple was inserted between two test pieces A, and the test pieces were pressed using upper and lower hot plates (pressing pressure was 0.5 MPa). The temperature of the upper and lower hot plates was set to 135°C when the polymerization initiator contained in the prepreg resin composition was Trigonox 122-C80, and to 105°C when it was Trigonox 421-70 described later. At this time, the cure time (hereinafter referred to as "CT"), which is the time from the temperature of the thermocouple reaching the peak temperature from 30°C, was measured. The temperature of the test environment was 23±3°C. ＜Evaluation＞ ０: CT is within 60 seconds. ×: CT exceeds 60 seconds.

(4) Evaluation of molded body The obtained prepreg was layered so that the overall thickness was 2 mm. The obtained layered material was filled into the center of a flat plate mold coated with a mold release agent, and was compression molded using a compression molding machine under the conditions of a pressure of 4 MPa, an upper mold temperature of 140°C, a lower mold temperature of 135°C, and a molding time of 3 minutes. Then, it was cut into strips of 125 mm in length and 13 mm in width to produce a test piece B as a molded body. A vertical combustion test was performed in accordance with UL94V. The upper end of the test piece B was vertically mounted on a clamping plate, and cotton was placed 300 mm below the test piece B. Using a gas burner, a blue flame of methane gas (height 20 mm) was brought into contact with the lower end of the test piece B for 10 seconds, and the burning time was measured. When the burning time was within 30 seconds, the flame was brought into contact for another 10 seconds, and the burning time was measured. Observe whether the cotton was ignited by the falling of the dripping material, and whether the burning reached the clip mounting part. These operations were performed on 5 test pieces B. The judgment criteria are shown in Table 1.

[Table 1] ＜UL94 Criteria＞ Determination items V-0 V-1 V-2 V is not suitable Flaming time after each flame contact (seconds) ≦10 ≦30 ≦30 Other than V-0, V-1, V-2 Total flaming time of 5 test pieces B (seconds) ≦50 ≦250 ≦250 Total of flaming burning time and flameless burning time after second flame contact (seconds) ≦30 ≦60 ≦60 Does combustion reach the clip installation area? without without without Is there any fire in cotton? without without have [Example 2]

In this embodiment, Rabitle FP-110 (Mitsui Fine Chemical Co., Ltd.: phosphazene series) is used instead of Fire Cut P-770 as a halogen-free flame retardant, and the resin composition for prepreg is prepared in the same manner as in Example 1. The phosphazene compound contained in the halogen-free flame retardant is a phosphorus compound that does not contain halogen and active hydrogen. Furthermore, the phosphazene compound is not equivalent to ammonium phosphate. Using the obtained resin composition for prepreg, a prepreg is prepared in the same manner as in Example 1. From the obtained prepreg, a test piece A is prepared in the same manner as in Example 1 and evaluated. Furthermore, a test piece B as a molded body was prepared from the obtained prepreg in the same manner as in Example 1 and evaluated. [Example 3]

In this embodiment, 20.0 parts by mass of CR-733S (manufactured by Daihachi Chemical Industry Co., Ltd.: aromatic condensed phosphate) was used as a halogen-free flame retardant instead of 30.0 parts by mass of Fire Cut P-770. The resin composition for prepreg was prepared in the same manner as in Example 1. Using the obtained resin composition for prepreg, a prepreg was prepared in the same manner as in Example 1. Test piece A was prepared from the obtained prepreg in the same manner as in Example 1 and evaluated. Furthermore, test piece B as a molded body was prepared from the obtained prepreg in the same manner as in Example 1 and evaluated. [Example 4]

In this embodiment, 2.0 parts by mass of "Trigonox 421-70" (organic peroxide) manufactured by KAYAKU NOURYON Co., Ltd. was used as a polymerization initiator instead of 1.0 parts by mass of Trigonox 122-C80. The resin composition for prepreg was prepared in the same manner as in Example 1. Using the obtained resin composition for prepreg, a prepreg was prepared in the same manner as in Example 1. Test piece A was prepared from the obtained prepreg in the same manner as in Example 1 and evaluated. Furthermore, using the obtained prepreg, the molding conditions were changed to pressure 4 MPa, upper mold temperature 110°C, lower mold temperature 105°C, and molding time 8 minutes. In addition, the test piece B as a molded body was prepared and evaluated in the same manner as in Example 1. [Example 5]

In this embodiment, 2.0 parts by mass of "Trigonox 421-70" (organic peroxide) manufactured by KAYAKU NOURYON Co., Ltd. was used as a polymerization initiator instead of 1.0 parts by mass of Trigonox 122-C80, and 30 parts by mass of Rabitle FP-110 was used as a halogen-free flame retardant instead of Fire Cut P-770. The resin composition for prepreg was used to prepare a prepreg in the same manner as in Example 1. Test piece A was prepared from the obtained prepreg in the same manner as in Example 1 and evaluated. Furthermore, using the obtained prepreg, the molding conditions were changed to pressure 4 MPa, upper mold temperature 110°C, lower mold temperature 105°C, and molding time 8 minutes. In addition, the test piece B as a molded body was prepared and evaluated in the same manner as in Example 1. [Example 6]

In this embodiment, 2.0 parts by mass of "Trigonox 421-70" (organic peroxide) manufactured by KAYAKU NOURYON Co., Ltd. was used as a polymerization initiator instead of 1.0 parts by mass of Trigonox 122-C80, and 20.0 parts by mass of CR-733S (aromatic condensed phosphate manufactured by Dahachi Chemical Industry Co., Ltd.) was used as a halogen-free flame retardant instead of 30.0 parts by mass of Fire Cut P-770. Using the obtained prepreg resin composition, a prepreg was prepared in the same manner as in Example 1. From the obtained prepreg, a test piece A was prepared and evaluated in the same manner as in Example 1. Furthermore, using the obtained prepreg, the molding conditions were changed to a pressure of 4 MPa, an upper mold temperature of 110°C, a lower mold temperature of 105°C, and a molding time of 8 minutes. In addition, a test piece B as a molded body was prepared and evaluated in the same manner as in Example 1.

[Comparative Example 1] In this comparative example, no flame retardant was added, and the resin composition for prepreg was prepared in the same manner as in Example 1. Using the obtained resin composition for prepreg, a prepreg was prepared in the same manner as in Example 1. Test piece A was prepared from the obtained prepreg in the same manner as in Example 1 and evaluated. Furthermore, test piece B as a molded body was prepared from the obtained prepreg in the same manner as in Example 1 and evaluated.

[Comparative Example 2] In this comparative example, 20.0 parts by mass of MC-6000 (manufactured by Nissan Chemical Co., Ltd.: melamine cyanurate series) was used as a halogen-free flame retardant instead of 30.0 parts by mass of Fire Cut P-770. The resin composition for prepreg was prepared in the same manner as in Example 1, except that the halogen-free flame retardant was used. Melamine cyanurate contained in the halogen-free flame retardant is a phosphorus-free compound. Using the obtained resin composition for prepreg, a prepreg was prepared in the same manner as in Example 1. From the obtained prepreg, a test piece A was prepared in the same manner as in Example 1 and evaluated. Furthermore, the obtained prepreg was used to prepare a test piece B as a molded body in the same manner as in Example 1 and evaluated.

[Comparative Example 3] In this comparative example, 2.0 parts by mass of "Trigonox 421-70" (organic peroxide) manufactured by KAYAKU NOURYON Co., Ltd. was used as a polymerization initiator instead of 1.0 parts by mass of Trigonox 122-C80, and no flame retardant was added. The resin composition for prepreg was prepared in the same manner as in Example 1. Using the obtained resin composition for prepreg, a prepreg was prepared in the same manner as in Example 1. From the obtained prepreg, a test piece A was prepared in the same manner as in Example 1 and evaluated. Furthermore, using the obtained prepreg, the molding conditions were changed to pressure 4 MPa, upper mold temperature 110°C, lower mold temperature 105°C, and molding time 8 minutes. In addition, the test piece B as a molded body was prepared and evaluated in the same manner as Example 1.

The formulation of the prepreg resin composition, the evaluation results of the prepreg, and the evaluation results of the molded article are shown in Tables 2 and 3 below.

[Table 2] Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Polyisocyanate MR-200 29.0 29.0 29.0 29.0 MDI 9.9 9.9 9.9 9.9 Monool HEMA 26.9 26.9 26.9 26.9 Polyols BPE-20 6.3 6.3 6.3 6.3 BPE-40 8.9 8.9 8.9 8.9 PEG-300 0.7 0.7 0.7 0.7 Thermoplastic resin MDI/PTMG1000/1,4-BG 6.3 6.3 6.3 6.3 Polymerizable monomer M-245 12.0 12.0 12.0 12.0 Polymerization initiator 122-C80 1.0 1.0 1.0 421-70 2.0 Halogen-free flame retardant Fire Cut P-770 30.0 30.0 Rabitle FP-110 30.0 CR-733S 20.0 MC-6000 Evaluation of rapid curing properties of prepreg CT (seconds) until the temperature reaches 135℃ 52 49 46 - CT (seconds) until the temperature reaches 105℃ - - - 55 Quick hardening judgment (within 60 seconds) ○ ○ ○ ○ Forming conditions Pressure (MPa) 4 4 4 4 Upper mold temperature (℃) 140 140 140 110 Lower mold temperature (℃) 135 135 135 105 Forming time (minutes) 3 3 3 8 Flame retardant evaluation after molding UL94 determination V-0 V-1 V-1 V-0 Flame retardant determination ○ ○ ○ ○

[Table 3] Embodiment 5 Embodiment 6 Comparison Example 1 Comparison Example 2 Comparison Example 3 Polyisocyanate MR-200 29.0 29.0 29.0 29.0 29.0 MDI 9.9 9.9 9.9 9.9 9.9 Monoalcohol HEMA 26.9 26.9 26.9 26.9 26.9 Polyols BPE-20 6.3 6.3 6.3 6.3 6.3 BPE-40 8.9 8.9 8.9 8.9 8.9 PEG-300 0.7 0.7 0.7 0.7 0.7 Thermoplastic resin MDI/PTMG1000/1,4-BG 6.3 6.3 6.3 6.3 6.3 Polymerizable monomer M-245 12.0 12.0 12.0 12.0 12.0 Polymerization initiator 122-C80 1.0 1.0 421-70 2.0 2.0 2.0 Halogen-free flame retardant Fire Cut P-770 Rabitle FP-110 30.0 CR-733S 20.0 MC-6000 30.0 Evaluation of rapid curing properties of prepreg CT (seconds) until the temperature reaches 135℃ - - 40 90 - CT (seconds) until the temperature reaches 105℃ 51 49 - - 42 Quick hardening judgment (within 60 seconds) ○ ○ ○ × ○ Forming conditions Pressure (MPa) 4 4 4 4 4 Upper mold temperature (℃) 110 110 140 140 110 Lower mold temperature (℃) 105 105 135 135 105 Forming time (minutes) 8 8 3 3 8 Flame retardant evaluation after molding UL94 determination V-1 V-1 V is not suitable V is not suitable V is not suitable Flame retardant determination ○ ○ × × ×

The prepregs of Examples 1 to 6 contain a halogen-free phosphorus compound as a flame retardant. As shown in Tables 2 and 3, the molded bodies made from the prepregs of Examples 1 to 6 were all rated as V-0 or V-1 by UL94. Based on this, it was confirmed that the prepregs of Examples 1 to 6 can produce molded bodies with excellent flame retardancy. Furthermore, it was confirmed that the time until the peak temperature was reached in the prepregs of Examples 1 to 6 was short, and all had excellent rapid curing properties.

On the other hand, the prepregs of Comparative Examples 1 and 3 do not contain any flame retardant. In addition, the prepreg of Comparative Example 2 contains a halogen-free and phosphorus-free compound as a flame retardant. As shown in Table 3, in the molded bodies made from the prepregs of Comparative Examples 1 to 3, the UL94 judgment is not equivalent to any of V-0 to V-2. Based on this situation, it was confirmed that the prepregs of Comparative Examples 1 to 3 cannot produce molded bodies with excellent flame retardancy. Furthermore, it was confirmed that in the prepreg of Comparative Example 2, the time until the peak temperature is reached is long, and the rapid curing property is poor.

without

without

Claims (4)

A prepreg characterized by containing: urethane (meth) acrylate (A), ethylenically unsaturated monomers (B) other than the urethane (meth) acrylate (A), a polymerization initiator (C), a reinforcing fiber (D), and a flame retardant (E), The urethane (meth) acrylate (A) is a reaction product of polyisocyanate (a1) and a polyol (a2) having an ethylenically unsaturated group and an aromatic skeleton, and/or a reaction product of polyisocyanate (a1) and a polyol (a3) having no ethylenically unsaturated group but an aromatic skeleton and a hydroxyalkyl (meth) acrylate (a4), The flame retardant (E) contains one or more halogen-free phosphorus compounds. The prepreg as described in claim 1, wherein the halogen-free phosphorus compound is a phosphorus compound free of active hydrogen. The prepreg as described in claim 1, wherein the halogen-free phosphorus compound is ammonium phosphate. A molded product, characterized in that it is a cured product of the prepreg as described in any one of claims 1 to 3.