Prepreg and fiber-reinforced plastic

Abstract

Provided is a prepreg that suppresses odor and can suppress deterioration in physical properties during molding of fiber-reinforced plastic.　A prepreg 10 is obtained by impregnating a resin 20 with a resin composition 30, wherein the resin composition 30 contains a (meth)acrylate resin and a fragrance component which masks odor of the (meth)acrylate resin.

Description

Prepreg and Fiber Reinforced Plastic

[0001] The present invention relates to a prepreg in which fibers are impregnated with a resin, and a fiber reinforced plastic using the prepreg.

[0002] Conventionally, a sheet-like prepreg in which fibers such as carbon fibers are impregnated with a resin is laminated to obtain a fiber reinforced plastic which is a laminate (see Patent Document 1). The prepreg before use (during storage) usually has carrier films (release films) laminated on both sides. When in use, the prepreg with the carrier film is cut into an arbitrary size, the carrier film is peeled off, and then the prepreg is laminated. After lamination, it is molded into a desired shape to obtain a fiber reinforced plastic (FRP). The lamination of the prepreg may be performed by hand by an operator or by a machine.

[0003] When manufacturing a fiber reinforced plastic by laminating prepregs, the resin impregnated in the prepregs may scatter and adhere to devices and work clothes around the workplace. In addition, among the resins contained in the prepregs, the odor of (meth)acrylate resins in particular is an odor recognized as an unpleasant odor. Therefore, even after the work is completed and the prepregs are removed from the workplace, if the resin adheres to the devices and work clothes, the odor (unpleasant odor) derived from the resin remains at the site. Further, even when there are no prepregs or resins in the workplace after the work is completed, the causative components (odor components) of the odor volatilized from the resin may stay in the factory, and there is a possibility that the odor remains in the factory for about two to three days.

[0004] In order to suppress such an odor, conventionally, local odor countermeasures have been taken, such as sealing the location where the odor is generated, connecting an exhaust duct to the sealed location, and exhausting the odor outdoors from the exhaust port of the exhaust duct by an exhaust fan or the like. However, when there are residential areas or the like around the factory, the odor discharged outside the factory becomes a problem in the vicinity. Therefore, in order to solve such a problem, deodorization and odor elimination treatment for capturing odor components in the vicinity of the exhaust port in the exhaust duct have been performed to prevent odor leakage to the surroundings.

[0005] The exhaust systems described above require space and a suitable environment for installation, thus limiting their use to specific locations and environments. Furthermore, in the case of prepregs, if the resin adheres to equipment or work clothes, it will travel outside the factory along with these items, generating odors at each destination. Installing such exhaust systems at each destination is difficult.

[0006] Therefore, in order to suppress the above-mentioned odor, it is necessary to improve the odor of the resin composition itself. Furthermore, in order to improve the odor, it is also necessary to suppress the deterioration of physical properties when molding fiber-reinforced plastics using prepregs.

[0007] Japanese Patent Publication No. 2023-158535

[0008] In view of the above circumstances, the present invention aims to provide a prepreg that suppresses odor and reduces the deterioration of physical properties when molding fiber-reinforced plastics, and a fiber-reinforced plastic using said prepreg.

[0009] The characteristic configuration of the prepreg according to the present invention for solving the above problems is a prepreg in which fibers are impregnated with a resin composition, wherein the resin composition contains a (meth)acrylate resin and a fragrance component that masks the odor of the (meth)acrylate resin.

[0010] With this prepreg configuration, the odor volatilized from the (meth)acrylate resin can be masked by the fragrance volatilized from the fragrance components, thus suppressing the odor. Furthermore, when molding fiber-reinforced plastic, the generation of gases caused by the above-mentioned fragrance components is suppressed, thus preventing a deterioration in the physical properties of the fiber-reinforced plastic.

[0011] In the prepreg with this configuration, the content of the fragrance component is preferably 0.1 to 2% by mass.

[0012] With this prepreg configuration, by setting the fragrance component content in the prepreg within the above range, the odor volatilized from the (meth)acrylate resin can be better masked by the fragrance volatilized from the fragrance component, resulting in a more suppressed odor. Furthermore, when molding fiber-reinforced plastic, the generation of gases caused by the fragrance component is further suppressed, thus further suppressing the deterioration of the physical properties of the fiber-reinforced plastic.

[0013] In the prepreg of this configuration, the content of the fragrance component is preferably 0.2 to 3 parts by mass per 100 parts by mass of the (meth)acrylate resin.

[0014] With this prepreg configuration, by setting the fragrance component content to the above range relative to 100 parts by mass of (meth)acrylate resin, the odor volatilized from the (meth)acrylate resin can be better masked by the fragrance volatilized from the fragrance component, resulting in a more suppressed odor. Furthermore, when molding fiber-reinforced plastic, the generation of gases caused by the fragrance component is further suppressed, thus further suppressing the deterioration of the physical properties of the fiber-reinforced plastic.

[0015] In the prepreg of this configuration, when plotting the viscoelasticity among the dynamic mechanical properties measured in accordance with JIS K7244-4:1999, it is preferable that the minimum melt viscosity, which is shown as the lowest value of the viscoelastic properties, is 0.01 to 30 Pa·s.

[0016] With this prepreg configuration, by setting the minimum melt viscosity within the above range, the flow state of the (meth)acrylate resin becomes appropriate when molding fiber-reinforced plastic using the prepreg, thereby suppressing voids and, as a result, further suppressing the deterioration of the physical properties of the fiber-reinforced plastic.

[0017] In the prepreg of this configuration, the content of the resin composition is preferably 20 to 60% by mass.

[0018] With this prepreg configuration, by setting the resin composition content within the above range, the mechanical properties of the fiber-reinforced plastic manufactured from the prepreg can be further enhanced.

[0019] In the prepreg of this configuration, the content of (meth)acrylate resin in the resin composition is preferably 88 to 98.9% by weight.

[0020] With this prepreg configuration, the strength of the fiber-reinforced plastic produced from the prepreg can be increased by setting the (meth)acrylate resin content within the above range.

[0021] In the prepreg with this configuration, it is preferable that the amount of the fragrance component that volatilizes at 160°C is 20 to 80% of the initial content.

[0022] With this prepreg configuration, by setting the volatilization rate of the fragrance component at 160°C within the above range, the odor volatilized from the (meth)acrylate resin can be better masked by the fragrance volatilized from the fragrance component, resulting in a more suppressed odor. Furthermore, when molding fiber-reinforced plastic, the generation of gases caused by the fragrance component is further suppressed, thus further suppressing the deterioration of the physical properties of the fiber-reinforced plastic.

[0023] In the prepreg with this configuration, the fibers are preferably bundled in quantities of 1,000 to 30,000.

[0024] With this prepreg configuration, the tensile strength of the fibers can be made appropriate by setting the fiber bundles within the above range.

[0025] In the prepreg of this configuration, the fineness of the fibers is preferably 66 to 1800 tex.

[0026] With this prepreg configuration, the tensile strength of the fibers can be made appropriate by setting the fineness of the fibers within the above range.

[0027] Another characteristic feature of the fiber-reinforced plastic according to the present invention, which solves the above problems, is that the prepregs are laminated.

[0028] With this fiber-reinforced plastic configuration, using the above-mentioned prepreg suppresses odor and prevents deterioration of physical properties.

[0029] In the fiber-reinforced plastic of this configuration, the void ratio is preferably 0.01 to 6%.

[0030] With this fiber-reinforced plastic configuration, setting the void ratio within the above range further suppresses the deterioration of physical properties.

[0031] Figure 1 is a schematic perspective view showing a prepreg according to one embodiment of the present invention. Figure 2 is a schematic cross-sectional view showing a fiber-reinforced plastic according to one embodiment of the present invention. Figure 3 is a diagram showing an overview of the method for evaluating spatial odor in the examples and comparative examples. Figure 4 is a graph plotting an example of the viscoelastic properties of the prepreg.

[0032] The prepreg and fiber-reinforced plastic of the present invention will be described with reference to the drawings. However, the layer structure shown in the drawings has been exaggerated or simplified as appropriate for the sake of clarity, and the relative thicknesses and scales of each layer do not necessarily accurately reflect the actual prepreg and fiber-reinforced plastic.

[0033] [Prepreg] Figure 1 is a schematic perspective view of a prepreg according to one embodiment of the present invention. The prepreg 10 is made by impregnating fibers 20 with a resin composition 30. The resin composition 30 contains a (meth)acrylate resin and a fragrance component that masks the odor of the (meth)acrylate resin.

[0034] <Fibers> Examples of fibers 20 include carbon fibers, glass fibers, aramid fibers, alumina fibers, silicon carbide fibers, boron fibers, metal fibers, natural fibers, mineral fibers, synthetic fibers, and chemical fibers. Of these, carbon fibers are preferred. The fibers 20 are arranged in one direction within the prepreg 10.

[0035] Examples of carbon fibers include polyacrylonitrile (PAN) carbon fibers and pitch carbon fibers. By selecting carbon fibers as fiber 20, the physical properties (mechanical properties, etc.) of the fiber-reinforced plastic 1 (see Figure 2) can be further enhanced. Fiber 20 can be used alone, but it can also be used as a composite fiber or blended yarn of two or more types.

[0036] Multiple fibers 20 are bundled together to form a fiber bundle. The fiber bundle of fiber 20 preferably contains 1,000 to 30,000 fibers, and more preferably 3,000 to 24,000 fibers. By setting the fiber bundle of fiber 20 within the above range, the tensile strength of fiber 20 can be made appropriate.

[0037] The fineness (mass in grams per 1000 meters) of the fiber 20 is preferably 66 to 1800 tex, and more preferably 200 to 1650 tex. By setting the fineness of the fiber 20 within the above range, the tensile strength of the fiber 20 can be made appropriate.

[0038] <Resin Composition> Resin composition 30 is a resin composition for prepregs and contains a (meth)acrylate resin and a fragrance component that masks the odor of the (meth)acrylate resin. In this specification, (meth)acrylate resin means acrylate resin and / or methacrylate resin.

[0039] The (meth)acrylate resin can be any resin having (meth)acrylate groups and is not particularly limited. The (meth)acrylate resin is volatile and, upon volatilization, generates an odor (unpleasant odor) due to the (meth)acrylate groups. Therefore, it is necessary to mask the odor of the (meth)acrylate resin. Examples of such (meth)acrylate resins include urethane (meth)acrylate, urethane-modified vinyl ester, and unsaturated polyester having (meth)acrylate groups.

[0040] The (meth)acrylate resin content in the resin composition 30 is preferably 88 to 98.9% by mass. By setting the (meth)acrylate resin content within the above range, the strength of the fiber-reinforced plastic 1 manufactured from the prepreg 10 can be increased.

[0041] <Fragrance Components> The fragrance components are intended to mask the odor of the (meth)acrylate resin. The fragrance components are not particularly limited, as long as they are capable of masking the odor of the (meth)acrylate resin.Fragrance components include, for example, camphor, 3-(4-tert-butylphenyl)-2-methylpropanal, benzyl alcohol, 2-phenoxyethyl isobutyrate, 3-(4-isopropylphenyl)-2-methylpropanal, 5-heptyloxolan-2-one, (2E)-3,7-dimethylocta-2,6-dienyl acetate, oxacyclohexadecane-2-one, (E)-3,7-dimethylocta-2,6-dien-1-ol, 3,7-dimethylocta-1,6-dien-3-yl acetate, 7 -Methyl-3-methyleneocta-1,6-diene, 2,6-di-tert-butyl-4-cresol, 4,6,6,7,8,8-hexamethyl-1,3,4,6,7,8-hexahydrocyclopenta[g]isochromene (HHCB), hexyl-2-hydroxybenzoate, methyl-2-(3-oxo-2-pentylcyclopentyl)acetate, 2-hydroxybenzoate (Z)-3-hexenyl, 2-tert-butylcyclohexyl acetate, 3,7-dimethyl-6-octennitrile, 2-benzylidene octanol, (E) -4-(2,6,6-trimethylcyclohexa-1-en-1-yl)buta-3-en-2-one, phenethyl acetate, d-limonene, alkanol (1-octanol, etc.), 2-methyl-1-phenyl-2-propyl acetate, lemon flavor, β-damascone, orange flavor, geranyl acetate, 2-isobutyl-4-methyltetrahydrobilan-4-ol, coumarin, 2-benzylidene octanal, ethyl vanillin, damascone, cyclamenaldehyde, bourgeonal, linalool, 2,4,6-trimethyl-4-phenyl-1,3-di Examples include oxane, decanal, hexyl acetate, terpineol, ethyl hexanoate, ethyl butyrate, styraryl acetate, ethyl β-methyl β-phenylglycidate, geraniol, 2,4-dimethyl-3-cyclohexenylcarbaldehyde, dodecanal, nerol, neryl acetate, phenethyl alcohol, citronellol, dihydromyrcenolate, piperonal, γ-undecalactone, benzyl acetate, allylheptanoate, methyldihydrojasmonate, benzyl benzoate, ethylhexanoate, and ethyl butyrate.Among these compounds, linalool, oxacyclohexadecane-2-one, ethyl vanillin, 2,4,6-trimethyl-4-phenyl-1,3-dioxane, alkanol (such as 1-octanol), decanal, hexyl acetate, terpineol, ethyl hexanoate, ethyl butyrate, styrallyl acetate, ethyl β-methyl-β-phenylglycidate, geraniol, 2,4-dimethyl-3-cyclohexenyl carbaldehyde, dodecanal, nerol, neryl acetate, phenethyl alcohol, citronellol, dihydromyrcenol, 4,6,6,7,8,8-hexamethyl-1,3,4,6,7,8-hexahydrocyclopenta[g]isochromene (HHCB), piperonal, γ-undecalactone, benzyl acetate, allyl heptanoate, methyl dihydrojasmonate, benzyl benzoate, ethyl hexanoate, ethyl butyrate are preferred. The fragrance component can be used alone or as a mixture of two or more kinds.

[0042] The content of the fragrance component in the resin composition 30 is preferably 0.1 to 2% by mass, more preferably 0.2 to 0.6% by mass. Further, the content of the fragrance component is preferably 0.2 to 3 parts by mass, more preferably 0.2 to 0.6 parts by mass with respect to 100 parts by mass of the (meth)acrylate resin. By setting the content of the fragrance component within the above range, the odor volatilized from the (meth)acrylate resin can be more masked by the fragrance volatilized from the fragrance component, so that the odor is more suppressed. Further, when molding the fiber reinforced plastic 1 (see Figure 2), the generation of gas caused by the above fragrance component is more suppressed, so that the deterioration of the physical properties of the fiber reinforced plastic 1 can be more suppressed.

[0043] The content ratio (RC) of the resin composition 30 in the prepreg 10 is not particularly limited, but is preferably 20 to 60% by mass, more preferably 20 to 40% by mass. By setting the content (RC) of the resin composition 30 within the above range, the mechanical properties of the fiber reinforced plastic 1 produced from the prepreg 10 can be further enhanced.

[0044] In addition to the above (meth)acrylate resin and fragrance component, the resin composition 30 may appropriately contain conventionally known additives as long as the effects of the present invention are not impaired. For example, as a fixing agent for the fragrance of the fragrance component and a diluent, it may contain an organic solvent such as dipropylene glycol (DPG). In addition, polymerization initiators (thermal polymerization initiators that are peroxides such as peroxyketals, ketone peroxides, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxy esters, peroxydicarbonates, peroxycarbonates, etc.), polymerization inhibitors (piperidine derivatives, etc.), inorganic fine particles such as fine powder silica, pigments, elastomers, flame retardants (aluminum hydroxide, brominated compounds, phosphorus-based compounds, etc.), defoaming agents, and other additives may be contained in an appropriate amount. For example, when the resin composition 30 contains a polymerization initiator, the content of the polymerization initiator in the resin composition 30 is preferably 0.1 to 6% by mass, and more preferably 0.5 to 3% by mass.

[0045] The resin composition 30 can be produced by mixing and stirring the (meth)acrylate resin, the fragrance component, and other optional components with a conventionally known stirring device or the like, and heating as necessary.

[0046] The prepreg 10 can be produced by impregnating the fiber 20 with the resin composition 30. Examples of the method for impregnating the fiber 20 with the resin composition 30 include a method in which the uncured resin composition 30 is previously applied to a release sheet (not shown), the fiber 20 aligned in one direction is placed on the applied uncured resin composition 30, and impregnation is performed by passing it between a pair of rollers (not shown); a method in which the uncured resin composition 30 is applied to the fiber 20 aligned in one direction and then impregnation is performed by passing it between a pair of rollers. In these cases, the thickness of the prepreg 10 can be adjusted by adjusting the nip pressure of the pair of rollers. Further, the pair of rollers may be heated to lower the viscosity of the resin composition 30 while performing impregnation.

[0047] <Characteristics of the prepreg> The prepreg 10 preferably has a void ratio of 0.01 to 6% in the fiber-reinforced plastic 1 obtained by curing the prepreg 10, as described later. By setting the void ratio of the fiber-reinforced plastic 1 within the above range, the deterioration of the physical properties of the fiber-reinforced plastic 1 is further suppressed. The void ratio of the fiber-reinforced plastic 1 can be obtained by the method described later. The void ratio of the fiber-reinforced plastic 1 can be adjusted by adjusting the content of the fragrance component in the prepreg 10.

[0048] The prepreg 10 preferably has a fragrance component volatilization rate of 20-80% of its initial content at 160°C, more preferably 30-75%, and even more preferably 35-75%. For example, if the initial content of the fragrance component in the prepreg 10 is 1% by mass, heating the prepreg 10 to 160°C will cause 0.2-0.8% by mass of the fragrance component to volatilize. Furthermore, the amount of fragrance component volatilized at 160°C is preferably 0.02-1.6% by mass relative to the mass (100% by mass) of the resin composition 30 in the prepreg 10 before volatilization (i.e., before heating). By setting the amount of fragrance component volatilization at 160°C within the above range, the odor volatilized from the (meth)acrylate resin can be better masked by the fragrance volatilized from the fragrance component, resulting in a more suppressed odor. Furthermore, when molding the fiber-reinforced plastic 1, the generation of gases caused by the fragrance components is further suppressed, thus further suppressing the deterioration of the physical properties of the fiber-reinforced plastic 1. The amount of volatilization of the fragrance components can be measured by the measurement method described later. The amount of volatilization of the fragrance components can be adjusted by adjusting the amount of fragrance components.

[0049] When plotting the viscoelasticity of the viscoelastic curve, which is one of the dynamic mechanical properties of prepreg 10 measured in accordance with JIS K7244-4:1999, the minimum melt viscosity, which is shown as the lowest value of the viscoelastic curve, is preferably 0.01 to 30 Pa·s. Figure 4 is a graph plotting an example of the viscoelastic properties of prepreg 10. According to the graph in Figure 4, the minimum melt viscosity, which is shown as the lowest value of the viscoelastic curve, is 0.25 Pa·s. When molding fiber-reinforced plastic 1 using prepreg 10 having the viscoelastic properties of Figure 4, it has been confirmed that the flow state of the (meth)acrylate resin is good (data omitted). In this way, by setting the minimum melt viscosity to 0.01 to 30 Pa·s, when molding fiber-reinforced plastic 1 using prepreg 10, the flow state of the (meth)acrylate resin becomes appropriate, voids are suppressed, and as a result, the deterioration of the physical properties of fiber-reinforced plastic 1 can be further suppressed. The minimum melt viscosity can be adjusted by adjusting the content of the fragrance component.

[0050] [Fiber-reinforced plastic] Figure 2 is a schematic cross-sectional view showing a fiber-reinforced plastic according to one embodiment of the present invention. The fiber-reinforced plastic 1 of this embodiment is made up of multiple layers of prepregs 10.

[0051] According to the fiber-reinforced plastic 1 of this embodiment, by using the prepreg 10 described above, odor is suppressed and the deterioration of physical properties is suppressed.

[0052] The fiber-reinforced plastic 1 preferably has a void ratio of 0.01 to 6%. By setting the void ratio within this range, the deterioration of physical properties is further suppressed. As described above, the void ratio of the fiber-reinforced plastic 1 can be obtained by the method described later.

[0053] The fiber-reinforced plastic 1 can be manufactured by stacking multiple prepregs 10 and then applying heat pressing (heating and pressure). The pressure in the heat pressing is preferably set to 1 to 5 MPa, the heating temperature is preferably set to 110 to 150°C, and the holding temperature (the time for which the pressurized and heated state is maintained) is preferably set to 100 to 140 minutes. Figure 2 shows an example of a state in which three prepregs 10 are stacked, but the number of prepregs 10 to be stacked is not particularly limited and can be set appropriately depending on the application, etc. Carbon fiber reinforced plastic is preferred as the fiber-reinforced plastic 1. The physical properties can be improved by using carbon fiber reinforced plastic for the fiber-reinforced plastic 1.

[0054] The prepreg and fiber-reinforced plastic of the present invention will be described in more detail below with reference to examples.

[0055] [Raw Materials Used] <Fibers> Type: Carbon fiber Product name: Torayca T700-SC-12000, manufactured by Toray Industries, Inc. Specific gravity (D): 1.8 <(Meth)acrylate resins> ・Resin 1 Product name: EBECYL8409 (aliphatic urethane acrylate, bifunctional), manufactured by Daicel Ornex Co., Ltd. Specific gravity (E): 1.2 ・Resin 2 Product name: Epoxy ester 3000MK (bisphenol A diglycidyl ether methacrylate adduct), manufactured by Kyoeisha Chemical Co., Ltd. Specific gravity (E): 1.2 <Fragrance components> ・Fragrance 1 Component: Linalool Product name: SQUASH T14019459, manufactured by Takasago International Corporation ・Fragrance 2 Component: Oxacyclohexadecane-2-one Product name: SAVON F 12677, manufactured by Inoue Fragrance Manufacturing Co., Ltd. ・Fragrance 3 Ingredients: Ethyl vanillin Product name: THP25444, manufactured by Hasegawa Fragrance Co., Ltd. <Polymerization initiator> ・Polymerization initiator 1 (thermal polymerization initiator which is a peroxide) Ingredients: Peroxyketal Product name: Luperox® 531M80, manufactured by Sigma-Aldrich Japan G. K. Specific gravity (E): 0.9

[0056] [Examples 1-5] Resin 1 as a (meth)acrylate resin, fragrance 1 containing linalool as a fragrance component, and polymerization initiator 1 were mixed to obtain the prepreg resin compositions of Examples 1-5, so as to have the fragrance component content shown in Table 1.

[0057] [Examples 6-7] Resin 1 as a (meth)acrylate resin, fragrance 2 containing oxacyclohexadecane-2-one as a fragrance component, and polymerization initiator 1 were mixed to obtain the prepreg resin compositions of Examples 6-7, so as to have the fragrance component content shown in Table 1.

[0058] [Example 8] The resin 2 as a (meth)acrylate resin, the fragrance 3 containing ethyl vanillin as a fragrance component, and the polymerization initiator 1 were mixed to obtain the prepreg resin composition of Example 8, so as to have the fragrance component content shown in Table 1.

[0059] [Comparative Example 1] A resin composition for prepreg of Comparative Example 1 was obtained in the same manner as in Example 1, except that no fragrance components were included (the content was set to 0% by mass).

[0060] [Comparative Example 2] A resin composition for prepreg of Comparative Example 2 was obtained in the same manner as in Example 8, except that no fragrance components were included (the content was set to 0% by mass).

[0061] The obtained prepreg resin compositions were evaluated for product odor (masking properties) and spatial odor (comfort) using the evaluation methods described below. The minimum melt viscosity of the prepreg, the amount of volatilization of fragrance components, and the void ratio of the fiber-reinforced plastic using the prepreg were measured using the measurement methods described below. A comprehensive evaluation was then performed using the evaluation method described below. The results are shown in Table 1.

[0062] <Product Odor (Masking Properties)> Uncured prepreg resin compositions of Examples 1-8 and Comparative Examples 1-2 were applied to a release sheet (carrier film) in advance. Fibers aligned in one direction were placed on the applied uncured prepreg resin composition and impregnated by passing them between a pair of rollers to obtain a rectangular prepreg measuring 300 mm x 200 mm x 0.2 mm. The carrier film was peeled off, and the odor was smelled immediately after peeling, one day after peeling, and two days after peeling to check for the presence or absence of odor (resin odor) derived from (meth)acrylate resin, and evaluated according to the following criteria. (Criteria) A: No resin odor is detected immediately after peeling, one day after peeling, and two days after peeling. B: No resin odor is detected immediately after peeling, but a resin odor is detected one day after peeling. C: A resin odor is detected immediately after peeling.

[0063] <Space Odor (Comfort)> A prepreg was obtained in the same manner as described above for "Product Odor (Masking Properties)". The carrier film of the prepreg was peeled off, and as shown in Figure 3, 1 m ３ The prepreg was placed in a (1m x 1m x 1m) container, the lid was closed to seal the container, and the odor was diffused inside the container. Five evaluators were randomly selected, and after 3 hours, they opened the lid and smelled the odor inside the container to check for the presence or absence of an unpleasant odor, and evaluated it according to the following criteria: (Evaluation Criteria) A: None of the five evaluators detected an unpleasant odor. B: Three or four of the five evaluators detected an unpleasant odor. C: One or two of the five evaluators detected an unpleasant odor. D: None of the five evaluators detected an unpleasant odor.

[0064] <Volatility of Fragrance Components> A prepreg was obtained in the same manner as described above for "Product Odor (Masking Properties)". Test pieces were prepared by cutting the prepreg into 100 mm x 100 mm squares, and their mass (a) was measured. After measuring the mass (a), the test pieces were immersed in acetone (purity 99% or higher) for 10 minutes and then removed. This immersion in acetone and removal was repeated three times to dissolve the resin composition (resin composition for prepreg) in acetone. Next, the fibers remaining after dissolution were dried at 60°C for 1 hour, and the mass (b) after drying was measured. Using masses (a) and (b), the resin content (c) [mass %], which is the content of the resin composition in the prepreg, was calculated according to the following formula (I). Resin content (c) = (a - b) / a × 100 ... (I) Next, a test specimen was prepared by cutting the prepreg into a 100 mm × 100 mm square in the same manner as above, and its mass (d) was measured. Furthermore, the test specimen after measuring the mass (d) was heat-treated at 160°C for 1 hour to cure it and obtain a 0.2 mm thick plate-shaped fiber-reinforced plastic (FRP, in this case carbon fiber reinforced plastic (CFRP)). The mass (e) of this fiber-reinforced plastic was measured. Then, using the mass (d), (e), and resin content (c), the amount of volatilization (f) [mass %] of the fragrance component relative to the resin composition in the prepreg at 160°C was calculated according to the following formula (II). Volatilization amount (f) = {(d - e) / (d × c)} × 100 ... (II)

[0065] <Minimum Melt Viscosity> A prepreg was obtained in the same manner as described above for "Product Odor (Masking Properties)". Dynamic viscoelasticity of the prepreg was measured in accordance with JIS K7244-4:1999 using a dynamic viscoelasticity measuring device (model: Rheogel-E4000, manufactured by UBM Co., Ltd.). Using the measured values, viscosity was calculated according to the following formula (A), and a viscoelasticity curve (with temperature on the horizontal axis and viscosity on the vertical axis, showing the relationship between temperature and viscosity) was plotted as shown in Figure 4, and the minimum melt viscosity, indicated by the lowest value, was determined.

[0066] η ＋ : Viscosity G ＊ : Complex modulus of elasticity G′: Storage modulus of elasticity G″: Loss modulus of elasticity ω: Angular frequency f: Frequency

[0067] <Void Ratio> A prepreg was obtained in the same manner as described above for "Product Odor (Masking Properties)". Test specimens were prepared by cutting the prepreg into 100 mm x 100 mm squares, and their mass (A) was measured. After measuring the mass, the test specimens were immersed in acetone (purity 99% or higher) for 10 minutes and then removed. This immersion in acetone and removal process was repeated three times to dissolve the resin composition in acetone. Next, the remaining fibers after dissolution were dried at 60°C for 1 hour, and the mass (B) after drying was measured. Using masses (A) and (B), the resin content (C) [mass %], which is the content of the resin composition in the prepreg, was calculated according to the following formula (1). Resin content (C) = (A - B) / A × 100 ... (1) Next, using the specific gravity of the fibers (D) and the specific gravity of the (meth)acrylate resin (E), the fiber volume ratio (F) [volume %], which is the volume ratio of the fibers in the prepreg, was calculated according to the following formula (2). Fiber volume ratio (F) = {(100 - C) / D)} / [{(100 - C) / D} + (C / E)] × 100 ... (2) Next, using the fiber volume ratio (F), the resin volume ratio (G) [volume %], which is the volume ratio of the (meth)acrylate resin in the prepreg, was calculated according to the following formula (3). Resin volume fraction (G) = 100 - F ... (3) Next, using the specific gravity of the fibers (D), the specific gravity of the (meth)acrylate resin (E), the fiber volume fraction (F), and the resin volume fraction (G), the theoretical specific gravity (H) assuming a void ratio of 0% was calculated according to the following formula (4). Theoretical specific gravity (H) = D × F / 100 + E × G / 100 ... (4) Next, the prepreg was cut into 200 mm × 200 mm squares, and 10 pieces of prepreg were stacked (laminated) so that they all faced the same direction. Using an autoclave, the material was molded under the following molding conditions to obtain a 2 mm thick plate-shaped fiber-reinforced plastic (FRP, in this case carbon fiber reinforced plastic (CFRP)). (Molding conditions) - Heating rate: 3°C / min - Pressure: 0.5 MPa - Vacuum: -0.1 MPa - Holding temperature: 150°C - Holding time: 1 hour - Cooling rate: 10°C / min The specific gravity (I) of the fiber-reinforced plastic was measured using a hydrometer (product name: MDS300, manufactured by Alpha Mirage Co., Ltd.) in accordance with JIS K 7112:1999 (water test method).Then, using the theoretical specific gravity (H) and the specific gravity of the fiber-reinforced plastic (I), the void fraction (J) was calculated according to the following formula (5): Void fraction (J) = {1 - (I / H)} × 100 ... (5).

[0068] <Overall Evaluation> For Examples 1-8 and Comparative Examples 1-2, an overall evaluation was conducted based on the evaluation results of product odor and ambient odor according to the following criteria. (Evaluation Criteria) Excellent: Product odor is rated A and ambient odor is rated A Good: Product odor is rated A or B and ambient odor is rated B Fairly good: Product odor is rated A or B and ambient odor is rated C Poor: Product odor is rated C and ambient odor is rated D

[0069]

[0070] As shown in Table 1, prepregs containing the resin compositions for prepregs of Examples 1 to 8, which have (meth)acrylate resin and fragrance components, were shown to be superior in product odor (masking properties) and spatial odor (comfort) compared to prepregs containing the resin compositions for prepregs of Comparative Examples 1 to 2, which do not contain fragrance components. It was shown that when the fragrance component content was 0.1 to 2.0% by mass, the product odor (masking properties) and spatial odor (comfort) were even superior. It was also shown that the void ratio could be suppressed to 2.7 to 6.0.

[0071] The prepreg and fiber-reinforced plastic of the present invention can be suitably used, for example, as displays for laptops, tablets, and smartphones; sports equipment; reinforcing members for automobiles and electronic components; and tanks (containers) for holding liquids.

[0072] 1 Fiber-reinforced plastic 10 Prepreg 20 Fiber 30 Resin composition

Claims

1. A prepreg comprising fibers impregnated with a resin composition, wherein the resin composition comprises a (meth)acrylate resin and a fragrance component that masks the odor of the (meth)acrylate resin.

2. The prepreg according to claim 1, wherein the content of the fragrance component is 0.1 to 2% by mass.

3. The prepreg according to claim 1, wherein the content of the fragrance component is 0.2 to 3 parts by mass per 100 parts by mass of the (meth)acrylate resin.

4. The prepreg according to claim 1, wherein when the viscoelasticity among the dynamic mechanical properties measured in accordance with JIS K7244-4:1999 is plotted, the minimum melt viscosity shown as the lowest value of the viscoelastic curve is 0.01 to 30 Pa·s.

5. The prepreg according to claim 1, wherein the content of the resin composition is 20 to 60% by mass.

6. The prepreg according to claim 1, wherein the content of (meth)acrylate resin in the resin composition is 88 to 98.9% by weight.

7. The prepreg according to claim 1, wherein the amount of the fragrance component that volatilizes at 160°C is 20 to 80% of the initial content.

8. The prepreg according to claim 1, wherein the fibers are bundles of 1,000 to 30,000 strands.

9. The prepreg according to claim 1, wherein the fineness of the fiber is 66 to 1800 tex.

10. A fiber-reinforced plastic comprising a laminate of prepregs according to any one of claims 1 to 9.

11. The fiber-reinforced plastic according to claim 10, wherein the void ratio is 0.01 to 6%.

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