Prepreg, fiber-reinforced composite material, tubular body made of fiber-reinforced composite material, golf club shaft, fishing rod, automotive structural member, and exterior member

Abstract

To provide a prepreg composed of a resin composition which is superior in strength, elastic modulus, and heat resistance, as well as in weather resistance, and to provide a fiber-reinforced composite material, a tubular body made of fiber-reinforced composite material, a golf club shaft, a fishing rod, an automotive structural member, and an exterior member, each of which employs the prepreg and is superior in mechanical properties, heat resistance, and weather resistance.SOLUTION: A prepreg comprises reinforcing fibers and a resin composition, wherein the resin composition contains the following components [A] and [B], and fulfills the following conditions (1) and (2). Component [A]: xylene diamine-based epoxy resin. Component [B]: dicyandiamide. Condition (1): the content of component [A] is 15 pts.mass or more based on 100 pts.mass of the total epoxy resin. Condition (2): component [C] defined below is not contained, or if present, its content is 10 pts.mass or less based on 100 pts.mass of the total epoxy resin. Component [C]: amine-based epoxy resin having a glycidylamino group linked to an aromatic ring.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to prepregs, fiber-reinforced composite materials, and tubular bodies made of fiber-reinforced composite materials, which are suitably used for fiber-reinforced composite materials for aerospace applications, general industrial applications, and sports applications. The present invention also relates to golf club shafts and fishing rods using the tubular bodies made of the fiber-reinforced composite materials, and automotive structural members and exterior members using the fiber-reinforced composite materials.

Background Art

[0002] Fiber-reinforced composite materials using carbon fibers, aramid fibers, etc. as reinforcing fibers are widely used for structural materials such as aircraft and automobiles, and for sports and general industrial applications such as tennis rackets, golf club shafts, fishing rods, bicycles, and housings, by taking advantage of their high specific strength and specific modulus of elasticity. As the resin composition used for this fiber-reinforced composite material, thermosetting resins are mainly used from the viewpoints of heat resistance and productivity. Among them, epoxy resins are preferably used from the viewpoint of mechanical properties such as adhesiveness to reinforcing fibers.

[0003] In recent years, in order to apply fiber-reinforced composite materials to applications such as golf club shafts, fishing rods, and bicycles that require further weight reduction, improvements in various physical properties have been demanded. For example, in order to exhibit excellent bending strength in tubular bodies such as golf club shafts and fishing rods, high fiber-direction strength and non-fiber-direction strength are required for the fiber-reinforced composite material used, and these are greatly affected by the strength and modulus of elasticity of the epoxy resin itself used as the matrix resin. In addition, when processing the fiber-reinforced composite material into a final product, high heat resistance to withstand the processing heat is also required. Furthermore, the case of using the cross pattern of reinforcing fibers as a design by applying a clear coating to the surface of the fiber-reinforced composite material is increasing. Therefore, in addition to the cured product of the epoxy resin used as the matrix resin exhibiting excellent mechanical properties and heat resistance, the weather resistance of the cured product has also come to be regarded as important.

[0004] In Patent Document 1, since it is possible to achieve both mechanical properties and weather resistance, a composition has been studied in which an isocyanuric acid type epoxy resin and a novolac type epoxy resin are blended, and the blending amount of the glycidylamine type epoxy resin is limited to a certain amount or less.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the technology of Patent Document 1, it was considered that an epoxy resin having a glycidylamino group generally has an adverse effect on weather resistance when used in an amount of a certain amount or more. On the other hand, it has been required to achieve both mechanical properties and weather resistance in a higher region.

[0007] Therefore, an object of the present invention is to provide a prepreg composed of a resin composition excellent in strength, elastic modulus, heat resistance, and weather resistance, and a fiber-reinforced composite material, a tubular body made of a fiber-reinforced composite material, a golf club shaft, a fishing rod, an automobile structural member, and an exterior member using the prepreg, which are excellent in mechanical properties, heat resistance, and weather resistance.

Means for Solving the Problems

[0008] 1. A prepreg containing reinforcing fibers and a resin composition, wherein the resin composition contains the following components [A] to [B] and satisfies the following conditions (1) to (2). Component [A]: Xylylenediamine type epoxy resin Component [B]: Dicyandiamide Condition (1): The content of Component [A] is 15 parts by mass or more with respect to 100 parts by mass of the total epoxy resin. Condition (2): It does not contain component [C], or if it contains component [C], the content thereof is 10 parts by mass or less with respect to 100 parts by mass of the total epoxy resin. Component [C]: An amine-type epoxy resin in which a glycidylamino group is bonded to an aromatic ring 2. Component [D]: The prepreg according to 1 above, which contains 10 to 50 parts by mass of a novolak-type epoxy resin with respect to 100 parts by mass of the total epoxy resin. 3. The prepreg according to 1 or 2 above, wherein the content of component [A] in condition (1) is 25 parts by mass or more with respect to 100 parts by mass of the total epoxy resin, and component [D]: the prepreg contains 20 to 50 parts by mass of a novolak-type epoxy resin. 4. The prepreg according to any one of 1 to 3 above, which does not contain the above component [C]. 5. The prepreg according to any one of 1 to 4 above, wherein the resin cured product having a thickness of 1 mm obtained from the above resin composition is subjected to UV irradiation with a radiation exposure amount of 16 MJ / m 2 and the amount of change in color tone (color difference ΔE) of the resin cured product before and after UV irradiation is 10 or less. 6. A fiber-reinforced composite material formed by molding the prepreg according to any one of 1 to 5 above. 7. A tubular body made of a fiber-reinforced composite material formed by molding the prepreg according to any one of 1 to 5 above. 8. A golf club shaft using the tubular body made of the fiber-reinforced composite material according to 7 above. 9. A fishing rod using the tubular body made of the fiber-reinforced composite material according to 7 above. 10. An automobile structural member using the fiber-reinforced composite material according to 6 above. 11. An exterior member using the fiber-reinforced composite material according to 6 above.

Advantages of the Invention

[0009] According to the present invention, it is possible to obtain a prepreg made of a resin composition excellent in strength, elastic modulus, heat resistance, and also excellent in weather resistance, and a fiber-reinforced composite material, a tubular body made of a fiber-reinforced composite material, a golf club shaft, a fishing rod, an automobile structural member, and an exterior member, which are excellent in mechanical properties, heat resistance, and weather resistance, using the prepreg.

Best Mode for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described in detail.

[0011] The prepreg of the present invention contains a resin composition and reinforcing fibers. It is preferably composed of a resin composition and reinforcing fibers. The resin composition contains component [A] and component [B].

[0012] Component [A] in the present invention is a xylenediamine type epoxy resin. By including component [A], the strength, elastic modulus, and heat resistance of the resin cured product can be improved without deteriorating the weather resistance, and it becomes possible to obtain a fiber-reinforced composite material having excellent mechanical properties, heat resistance, and weather resistance.

[0013] Based on 100 parts by mass of the total epoxy resin contained in the resin composition, component [A] is contained in an amount of 15 parts by mass or more. The lower limit is preferably 20 parts by mass or more, and more preferably 25 parts by mass or more. The upper limit is preferably 80 parts by mass or less, and more preferably 60 parts by mass or less. By including component [A] within this range, the balance of the mechanical properties, heat resistance, and weather resistance of the resin cured product becomes good.

[0014] Examples of component [A] include metaxylenediamine type epoxy resin, paraxylenediamine type epoxy resin, orthoxylenediamine type epoxy resin, etc., and it is more preferable to use metaxylenediamine type epoxy resin. Different from component [C]: an amine type epoxy resin in which a glycidylamino group is directly bonded to an aromatic ring, such as diaminodiphenylmethane type epoxy resin, diaminodiphenylsulfone type epoxy resin, and aminophenol type epoxy resin, component [A] can exhibit the above-described effects.

[0015] Examples of commercially available products of metaxylenediamine type epoxy resin include "TETRAD (registered trademark)"-X (manufactured by Mitsubishi Gas Chemical Company, Inc.).

[0016] As the condition (2) in the present invention, it is necessary that the amine-type epoxy resin in which a glycidylamino group is bonded to the aromatic ring as component [C] is not contained, or even if it is contained, its content is 10 parts by mass or less with respect to 100 parts by mass of the total epoxy resin. Further, even if component [C] is contained, it is more preferably 5 parts by mass or less, and even more preferably 1 part by mass or less. That is, regarding the epoxy resin in which the glycidylamino group is bonded to the aromatic ring among the amine-type epoxy resins having a glycidylamino group, by setting the blending amount thereof to 10 parts by mass or less, a fiber-reinforced composite material having excellent weather resistance can be obtained without impairing the weather resistance of the cured resin. Among the amine-type epoxy resins having a glycidylamino group, even if it is a compound having an aromatic ring like component [A], it does not fall under component [C] unless it is a compound having an aromatic ring to which the glycidylamino group is directly bonded.

[0017] Examples of the amine-type epoxy resin in which a glycidylamino group is bonded to the aromatic ring of component [C] include a diaminodiphenylmethane-type epoxy resin, a diaminodiphenylsulfone-type epoxy resin, and an aminophenol-type epoxy resin.

[0018] Examples of commercially available products of the diaminodiphenylmethane-type epoxy resin include ELM434 (manufactured by Sumitomo Chemical Co., Ltd.), "Araldite (registered trademark)" MY720, MY721, MY9512, MY9663 (manufactured by Huntsman Advanced Materials Co., Ltd. above), "Epotoate (registered trademark)" YH-434 (manufactured by Nippon Steel Chemical & Materials Co., Ltd.), "jER (registered trademark)" 604 (manufactured by Mitsubishi Chemical Corporation), and the like.

[0019] Examples of commercially available products of the diaminodiphenylsulfone-type epoxy resin include TG3DAS (manufactured by Mitsui Chemicals Fine Co., Ltd.).

[0020] Examples of commercially available aminophenol type epoxy resins include ELM120, ELM100 (both manufactured by Sumitomo Chemical Co., Ltd.), "jER (registered trademark)" 630 (manufactured by Mitsubishi Chemical Corporation), "Araldite (registered trademark)" MY0500, MY0510, MY0600, MY0610 (all manufactured by Huntsman Advanced Materials Co., Ltd.), and the like.

[0021] In the present invention, it is preferable to contain component [D] novolac type epoxy resin. When component [D] is contained, the elastic modulus and heat resistance of the resin cured product are improved without impairing the weather resistance of the resin cured product, and a fiber-reinforced composite material having excellent mechanical properties, heat resistance, and weather resistance can be obtained.

[0022] It is preferable to contain 10 to 50 parts by mass of component [D] with respect to 100 parts by mass of the total epoxy resin contained in the resin composition. The lower limit is preferably 20 parts by mass or more, more preferably 25 parts by mass or more. The upper limit is preferably 45 parts by mass or less, more preferably 40 parts by mass or less. By containing component [D] within this range, the balance of the mechanical properties, heat resistance, and weather resistance of the resin cured product becomes good.

[0023] Among these, those in which the content of component [A] is 25 parts by mass or more and component [D] is contained in an amount of 20 to 50 parts by mass with respect to 100 parts by mass of the total epoxy resin contained in the resin composition are excellent in the mechanical properties of the resin cured product and have a good balance of heat resistance and weather resistance.

[0024] Further, in order to improve the balance between the flexural elastic modulus and heat resistance of the resin cured product, the softening point of component [D] novolac type epoxy resin is preferably 50°C or higher, more preferably 60°C or higher for the lower limit. The upper limit of the above softening point is preferably 120°C or lower, more preferably 110°C or lower.

[0025] Examples of component [D] include phenol novolac type epoxy resin and cresol novolac type epoxy resin.

[0026] Examples of commercially available phenol novolac type epoxy resins include "jER (registered trademark)" 152, 154 (both manufactured by Mitsubishi Chemical Corporation), EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.), "EPICLON (registered trademark)" N-740, N-770 (softening point: 70 °C), N-775 (softening point: 75 °C, both manufactured by DIC Corporation), and the like.

[0027] Examples of commercially available cresol novolac type epoxy resins include "EPICLON (registered trademark)" N-660 (softening point: 66 °C), N-665 (softening point: 70 °C), N-670 (softening point: 73 °C), N-673 (softening point: 78 °C), N-680 (softening point: 87 °C), N-690 (softening point: 93 °C), N-695 (softening point: 95 °C, all manufactured by DIC Corporation), and the like.

[0028] In the resin composition used in the present invention, epoxy resins other than those described above can be appropriately blended within a range that does not impair the effects of the present invention. Specifically, examples include bisphenol type, isocyanuric acid type, oxazolidone type, dicyclopentadiene type, hydantoin type, sorbitol type, glycerol type, trimethylolpropane type, pentaerythritol type, trishydroxyphenylmethane type, and tetraphenylol ethane type epoxy resins.

[0029] Among them, examples of commercially available bisphenol A type epoxy resins include "jER (registered trademark)" 825, 828, 834, 1001, 1002, 1003, 1003F, 1004, 1004AF, 1005F, 1006FS, 1007, 1009, 1010 (all manufactured by Mitsubishi Chemical Corporation), "EPICLON (registered trademark)" 850 (manufactured by DIC Corporation), "Epotoate (registered trademark)" YD-128 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), and "D.E.R. (registered trademark)" -331, 332 (both manufactured by Dow Chemical Company), and the like.

[0030] Examples of commercially available bisphenol F type epoxy resins include "Araldite (registered trademark)" GY282 (manufactured by Huntsman Advanced Materials Co., Ltd.), "jER (registered trademark)" 806, 807, 4005P, 4007P, 4010P (all of the above are manufactured by Mitsubishi Chemical Corporation), "EPICLON (registered trademark)" 830 (manufactured by DIC Corporation), and "Epotoate (registered trademark)" YD-170, YDF2001 (manufactured by Nippon Steel Chemical & Materials Co., Ltd.).

[0031] Examples of commercially available isocyanuric acid type epoxy resins include "TEPIC (registered trademark)" -G, -S, -L, -VL, -PAS B22 (all of the above are manufactured by Nissan Chemical Industries, Ltd.), "Araldite (registered trademark)" PT9810 (manufactured by Huntsman Advanced Materials Co., Ltd.).

[0032] Examples of commercially available oxazolidone type epoxy resins include AER4152, AER4151 (both are manufactured by Asahi Kasei E-Materials Corporation), "D.E.R. (registered trademark)" 852, 858 (both are manufactured by The Dow Chemical Company), TSR-400 (manufactured by DIC Corporation), ACR1348 (manufactured by ADEKA Corporation).

[0033] Component [B] in the present invention is dicyandiamide. Dicyandiamide is excellent in imparting high mechanical properties and heat resistance to the cured product of epoxy resin and is widely used as a curing agent for various epoxy resins. Also, since it is excellent in the weather resistance and storage stability of the epoxy resin composition, it can be preferably used. Examples of commercially available dicyandiamide include DICY7, DICY15 (both are manufactured by Mitsubishi Chemical Corporation).

[0034] In the present invention, since the balance of the mechanical properties, heat resistance, and weather resistance of the resin cured product is excellent, the content of component [B] is preferably 2 to 12 parts by mass with respect to 100 parts by mass of the total epoxy resin. More preferably, the lower limit is 4 parts by mass or more, and more preferably, the upper limit is 10 parts by mass or less.

[0035] In the resin composition used for the prepreg of the present invention, a curing accelerator may be blended from the viewpoint of controlling the curing rate. Examples of the curing accelerator include urea compounds and imidazole compounds, and urea compounds can be preferably used particularly from the viewpoint of the storage stability of the resin composition.

[0036] Examples of the urea compound include 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, phenyldimethylurea, toluene bisdimethylurea, and the like. Also, as commercially available products of aromatic urea compounds, DCMU99 (manufactured by Hodogaya Chemical Co., Ltd.) and "Omicure (registered trademark)" 24 (manufactured by PTI Japan Co., Ltd.) can be used.

[0037] In the resin composition used for the prepreg of the present invention, a specific low molecular compound may be blended as an additive within a range that does not impair the effects of the present invention. The specific low molecular compound here is a compound having a boiling point of 130°C or higher and a molecular weight m of 50 or more and 250 or less, having no epoxy group in the molecule, and having no curing ability for epoxy resin. Compounds such as amines, phenols that can undergo an addition reaction with epoxy resin, acid anhydrides that can copolymerize with epoxy resin, imidazoles that can be initiators for the self-polymerization reaction of epoxy resin, aromatic urea compounds, and tertiary amine compounds are compounds having curing ability for epoxy resin and are not included in the low molecular compounds here. Here, "having no curing ability for epoxy resin" means a property of not undergoing a chemical reaction with epoxy resin and not participating in the self-polymerization of epoxy resin.

[0038] It is considered that the above low molecular compound exists in the voids without being incorporated into the crosslinked structure formed by the reaction of epoxy resin and dicyandiamide, and this state is maintained even after the curing of the epoxy resin. As a result, it is considered that the elastic modulus of the obtained cured epoxy resin product becomes high. Also, by blending the above low molecular compound, not only a high elastic modulus but also a cured epoxy resin product with high elongation and high strength can be obtained.

[0039] Examples of such low-molecular compounds include amides such as N-methylformamide, N-methylacetamide, 2-pyrrolidone, N-methylpropionamide, N-ethylacetamide, N-methylacetanilide, and N,N'-diphenylacetamide, and diols such as ethanediol, propanediol, butanediol, pentanediol, hexanediol, and heptanediol. These compounds may be used alone or in appropriate combinations.

[0040] The resin composition used in the prepreg of the present invention may contain a thermoplastic resin as long as the effects of the present invention are not impaired. By incorporating a thermoplastic resin into the resin composition, it is possible to control the viscosity of the resin composition, the tackiness of the prepreg, and the fluidity of the resin composition when the prepreg is heat-cured, without impairing the heat resistance of the fiber-reinforced composite material. As such a thermoplastic resin, a thermoplastic resin having compatibility with an epoxy resin and having a hydrogen-bonding functional group capable of improving the adhesion between the resin and the reinforcing fiber is preferably used, and a phenoxy resin is more preferably used from the viewpoint of excellent weather resistance.

[0041] Commercially available phenoxy resins include "Phenotote (registered trademark)" YP-50, YP-50S, YP-70 (manufactured by Nippon Steel Chemical & Material Co., Ltd., etc.).

[0042] After producing a resin cured product with a thickness of 1 mm under the curing conditions of 90°C × 1 hour (heating rate to 90°C: 1.7°C / min) + 135°C × 2 hours (heating rate from 90°C to 135°C: 2.0°C / min), the resin composition in the prepreg of the present invention preferably has a color change amount (color difference ΔE) of 10 or less, more preferably 9 or less, when UV irradiation with a radiation exposure dose of 16 MJ / m 2 is performed. By setting the color difference ΔE of the resin cured product before and after UV irradiation at the above radiation exposure dose within such a range, a fiber-reinforced composite material having excellent weather resistance can be obtained. Here, when the radiation exposure dose is 16 MJ / m 2The UV irradiation refers to irradiation using an accelerated weathering tester (for example, Super Xenon Weather Meter SX-75, manufactured by Suga Test Instruments Co., Ltd.) under the conditions of an intensity of 180 W / m 2 , a black panel temperature of 63°C, a humidity of 50% RH, and irradiation for 102 minutes without water injection, and an intensity of 180 W / m 2 , a tank temperature of 28°C, a humidity of 99% RH, and irradiation for 18 minutes while injecting water, with one cycle being defined as such, and the irradiation being repeated 12 times (i.e., 24 hours). A weather resistance test is conducted under such irradiation conditions to examine the amount of change in the color tone (color difference ΔE) of the cured resin product. Also, the color difference ΔE of the cured resin product refers to the tristimulus values (L * , a * , b * ) obtained by the reflection method under the optical conditions of a D65 light source, a 10° field of view, and d / 8 excluding regular reflection light using a multi-light-source spectrophotometer (for example, MSC-P, manufactured by Suga Test Instruments Co., Ltd.), and is calculated by the following formula (I) using the differences in tristimulus values (ΔL * , Δa * , Δb * ) before and after the weather resistance test.

[0043] ΔE = {(ΔL * ) 2 +(Δa * ) 2 +(Δb * ) 2} 1 / 2 ···(I) The flexural modulus of the cured resin product obtained by curing the resin composition in the prepreg of the present invention is preferably 3.6 GPa or more, more preferably 4.0 GPa or more. There is no particular upper limit to the flexural modulus, but it is preferably 6.0 GPa or less. It is preferable that the flexural modulus is within the above range because the mechanical properties of the fiber-reinforced composite material are excellent.

[0044] The viscosity of the resin composition in the prepreg of the present invention at 50°C is preferably 1 Pa·s or more, preferably 10 Pa·s or more, and more preferably 100 Pa·s or more in producing the prepreg. Regarding the upper limit, it is preferably 10,000 Pa·s or less, and more preferably 1,000 Pa·s or less. By setting the viscosity of the resin composition at 50°C within the above range, it is preferable because a prepreg with excellent quality can be obtained. Such viscosity is measured using a dynamic viscoelasticity apparatus. As for the detailed conditions, the conditions described in the examples can be referred to. As the reinforcing fibers used in the prepreg and the fiber-reinforced composite material of the present invention, carbon fibers, graphite fibers, aramid fibers, glass fibers, etc. can be preferably mentioned, and carbon fibers are particularly preferable. The form and arrangement of the reinforcing fibers are not limited. For example, long fibers aligned in one direction, single tows, woven fabrics, knits, and fiber structures such as braided cords are used. As the reinforcing fibers, two or more types of carbon fibers, glass fibers, aramid fibers, boron fibers, PBO fibers, high-strength polyethylene fibers, alumina fibers, and silicon carbide fibers may be used in combination.

[0045] Specific examples of the carbon fibers include acrylic-based, pitch-based, and rayon-based carbon fibers, and acrylic-based carbon fibers with particularly high tensile strength are preferably used.

[0046] As the form of the carbon fibers, twisted yarns, untwisted yarns, and non-twisted yarns can be used. However, in the case of twisted yarns, since the orientation of the filaments constituting the carbon fibers is not parallel, it causes a decrease in the mechanical properties of the resulting carbon fiber-reinforced composite material. Therefore, untwisted yarns or non-twisted yarns with a good balance between the moldability and strength characteristics of the carbon fiber-reinforced composite material are preferably used.

[0047] The carbon fiber preferably has a tensile elastic modulus in the range of 200 to 440 GPa. The tensile elastic modulus of the carbon fiber is affected by the crystallinity of the graphite structure constituting the carbon fiber, and the higher the crystallinity, the higher the elastic modulus. This range is preferable because all of the rigidity and strength of the carbon fiber reinforced composite material are balanced at a high level. A more preferable tensile elastic modulus is in the range of 230 to 400 GPa, and even more preferably in the range of 260 to 370 GPa. Here, the tensile elastic modulus of the carbon fiber is a value measured according to JIS R7601 (2006).

[0048] The prepreg of the present invention can be manufactured by various known methods. For example, the prepreg can be manufactured by a hot melt method in which the resin composition is made low-viscosity by heating without using an organic solvent and is impregnated into the reinforcing fiber.

[0049] In the hot melt method, a method of directly impregnating the reinforcing fiber with the resin composition made low-viscosity by heating, or a method of first producing a release paper sheet with a resin film in which the resin composition is once coated on a release paper or the like, and then overlapping the resin film from both sides or one side of the reinforcing fiber onto the reinforcing fiber side and heating and pressing to impregnate the reinforcing fiber with the resin composition can be used.

[0050] The content of the reinforcing fiber in the prepreg is preferably 30 to 90% by mass, more preferably 35 to 85% by mass, and still more preferably 65 to 85% by mass. If such a fiber mass content is small, the amount of resin is too large, and it is difficult to obtain the advantages of a fiber-reinforced composite material having excellent specific strength and specific elastic modulus. Also, when forming the fiber-reinforced composite material, the heat generation amount during curing may become too high. On the other hand, if the fiber mass content is too large, poor impregnation of the resin may occur, and the resulting composite material may have many voids. Also, there is a risk of impairing the tackiness of the prepreg.

[0051] The fiber-reinforced composite material of the present invention, or the tubular body made of the fiber-reinforced composite material, can be manufactured, for example, by laminating the prepreg of the present invention described above in a predetermined form and applying pressure and heat to cure the resin. Here, as the method of applying heat and pressure, a press molding method, an autoclave molding method, a bagging molding method, a wrapping tape method, an internal pressure molding method, etc. are adopted.

[0052] In the method for forming a tubular body made of a fiber-reinforced composite material, the wrapping tape method is particularly preferably used. The wrapping tape method is a method of winding a prepreg around a mandrel or the like to obtain a cylindrical molded body. Specifically, it is a method of winding a prepreg around a mandrel, winding a wrapping tape made of a thermoplastic resin film around the outer periphery thereof for fixing the prepreg and applying pressure, heating and curing the resin in an oven, and then removing the mandrel to obtain a cylindrical molded body, which is suitable for producing tubular bodies such as golf club shafts and fishing rods.

[0053] When the resin composition according to the present invention is used, the cured product can exhibit excellent mechanical properties, heat resistance, and weather resistance. Therefore, the tubular body made of the fiber-reinforced composite material of the present invention can exhibit excellent bending strength, heat resistance, and weather resistance.

[0054] The fiber-reinforced composite material of the present invention, or the tubular body made of the fiber-reinforced composite material, can be widely used in aerospace applications, general industrial applications, and sports applications. More specifically, in general industrial applications, it is preferably used for structural members such as automobiles, ships, and railway vehicles, and exterior members for automobiles, ships, railways, and buildings. In sports applications, it is preferably used for golf club shafts, fishing rods, and rackets for tennis and badminton. Among them, the tubular body made of the fiber-reinforced composite material of the present invention can be preferably used for golf club shafts and fishing rods.

[0055] The upper and lower limits of the numerical ranges described above can be arbitrarily combined unless otherwise specified.

Examples

[0056] Hereinafter, the present invention will be described in detail with reference to examples. However, the scope of the present invention should not be construed as being limited to these examples. The unit "part" of the composition ratio means parts by mass unless otherwise noted. In addition, the measurement of various properties (physical properties) was carried out under an environment of a temperature of 23°C and a relative humidity of 50% unless otherwise noted. Also, the unit of the amount of each component in the table is parts by mass in all cases.

[0057] <Materials Used in Examples and Comparative Examples> (1) Reinforcing Fiber CO6347G (a two-directional cross made by Toray Industries, Inc., using "TORAYCA (registered trademark)" T300 (tensile modulus of elasticity: 230 GPa), basis weight 198 g / m 2 ) (2) Epoxy Resin · Component [A]: Xylylenediamine-type epoxy resin [A]-1 “TETRAD (registered trademark)”-X (meta-xylylenediamine-type epoxy resin, epoxy equivalent: 90, manufactured by Mitsubishi Gas Chemical Company, Inc.) · Component [C]: Amine-type epoxy resin in which a glycidylamino group is bonded to an aromatic ring [C]-1 “ARALDITE (registered trademark)” MY0600 (aminophenol-type epoxy resin, epoxy equivalent: 106, manufactured by Huntsman Advanced Materials (Japan) Ltd.) [C]-2 “SUMIEPOXY (registered trademark)” ELM434 (diaminodiphenylmethane-type epoxy resin, epoxy equivalent: 120, manufactured by Sumitomo Chemical Co., Ltd.) · Component [D]: Novolac-type epoxy resin [D]-1 “EPICLON (registered trademark)” N-695 (cresol novolac-type epoxy resin, epoxy equivalent: 214, manufactured by DIC Corporation) [D]-2 “EPICLON (registered trademark)” N-775 (phenol novolac-type epoxy resin, epoxy equivalent: 189, manufactured by DIC Corporation) · Component [E]: Other epoxy resins [E]-1 “EPICLON (registered trademark)” 830 (bisphenol F-type epoxy resin, epoxy equivalent: 172, manufactured by DIC Corporation) [E]-2 "Epoto (Registered Trademark)" YDF2001 (Bisphenol F type epoxy resin, epoxy equivalent: 485, manufactured by Nippon Steel Chemical & Material Co., Ltd.) [E]-3 "jER (Registered Trademark)" 828 (Bisphenol A type epoxy resin, epoxy equivalent: 189, manufactured by Mitsubishi Chemical Corporation) [E]-4 "TEPIC (Registered Trademark)"-S (Isocyanuric acid type epoxy resin, epoxy equivalent: 100, manufactured by Nissan Chemical Industries, Ltd.) [E]-5 "D.E.R. (Registered Trademark)" 858 (Oxazolidone type epoxy resin, epoxy equivalent: 400, manufactured by Dow Chemical Company) (3) Component [B]: Dicyandiamide [B]-1 DICY7 (Dicyandiamide, manufactured by Mitsubishi Chemical Corporation) (4) Other curing agents "Seikacure (Registered Trademark)"-S (4,4'-Diaminodiphenyl sulfone, manufactured by Wakayama Seika Co., Ltd.) "Cureduct (Registered Trademark)" P-0505 (Epoxy-imidazole adduct, manufactured by Shikoku Kasei Kogyo Co., Ltd.) "ANCAMINE (Registered Trademark)" 2049 (Bis(4-amino-3-methylcyclohexyl)methane, manufactured by Evonik Corporation) (5) Curing accelerators DCMU99 (3-(3,4-Dichlorophenyl)-1,1-dimethylurea, manufactured by Hodogaya Chemical Co., Ltd.) (6) Additives "Cureduct (Registered Trademark)" L-07N (Composition containing 5 parts by mass of boric acid ester compound, manufactured by Shikoku Kasei Kogyo Co., Ltd.) (Preparation method of resin composition) Table 1 shows the compositions of each example and comparative example. (1) Preparation of curing agent masterbatch In each of the examples and comparative examples, among the components of each example shown in the table, 10 parts by mass of an epoxy resin that is liquid at room temperature (any one of [A]-1, [C]-1, [C]-2, [E]-1, [E]-3) was prepared (10 parts by mass with respect to 100 parts by mass of all the epoxy resins contained in the resin composition). To this, component [B]: dicyandiamide was added in the amounts shown in the table, and kneaded at room temperature. The curing agent master was prepared by passing the mixture through a three-roll mill twice.

[0058] (2) Preparation of resin composition Among the components of each example shown in the table, excluding the amounts contained in the 10 parts by mass of the liquid epoxy resin used in (1) above, the epoxy resins related to component [C], component [D], and component [E] were put into a beaker, and the temperature was raised to 150 °C with kneading to dissolve them. Then, the temperature was lowered to 120 °C, and among the components of each example shown in the table, component [A] excluding the amount contained in the curing agent master prepared in (1) above was added and dissolved with kneading. Next, while continuing the kneading, the temperature was lowered to 55 - 65 °C, and then the curing agent master prepared in (1) above and the curing accelerator in the amounts and components of each example shown in the table were added, and kneaded at the same temperature for 30 minutes to obtain a resin composition. However, for Comparative Examples 4, 5, and 6, instead of using the above curing agent master, "SEIKACURE (registered trademark)"-S, "CUREDUCT (registered trademark)" P-0505, or "ANCAMINE (registered trademark)" 2049 was used as the curing agent respectively. For Comparative Example 5, after the temperature was lowered to 55 - 65 °C, "CUREDUCT (registered trademark)" L-07N was additionally blended.

[0059] <Method for producing resin cured product> After degassing the resin composition prepared according to the above <Method for preparing resin composition> in a vacuum, in a mold set to a thickness of 2 mm with a 2 mm thick "TEFLON (registered trademark)" spacer, the temperature was raised from 30 °C at a rate of 1.7 °C / min, and after reaching a temperature of 90 °C, held for 1 hour, then the temperature was raised at a rate of 2.0 °C / min, and after reaching a temperature of 135 °C, cured for 2 hours to obtain a plate-shaped resin cured product with a thickness of 2 mm.

[0060] For weather resistance test evaluation, the above-mentioned curing reaction was carried out in a mold set to a thickness of 1 mm with a 1-mm-thick spacer made of "Teflon (registered trademark)", and a plate-shaped resin cured product with a thickness of 1 mm was obtained. <Method for preparing prepreg> The resin composition prepared according to the above <Method for preparing resin composition> was applied onto a release paper using a knife coater to prepare a resin film having a resin basis weight of 66 g / m 2 . Next, a two-directional cross (the above-mentioned CO6347G) using carbon fiber "Torayca (registered trademark)" T300 (manufactured by Toray Industries, Inc.) was prepared. After laminating one resin film on each side of this, it was impregnated with heat and pressure from both sides using a prepreg forming apparatus to obtain a woven fabric prepreg. The resin content of the prepreg was 40% by mass.

[0061] <Various evaluation methods> (1) Three-point bending measurement of resin cured product From the resin cured product with a thickness of 2 mm prepared according to the above <Method for preparing resin cured product>, test pieces with a width of 10 mm and a length of 60 mm were cut out. Using an Instron universal testing machine (manufactured by Instron Corporation), with a span of 32 mm, a crosshead speed of 2.5 mm / min, and the number of samples n = 6, the average values of the strength and modulus of elasticity when performing three-point bending according to JIS K7171 (1994) were taken as the flexural strength and flexural modulus of elasticity of the resin cured product, respectively.

[0062] (2) Glass transition temperature measurement of resin cured product From the resin cured product with a thickness of 2 mm prepared according to the above <Method for preparing resin cured product>, test pieces with a width of 12.7 mm and a length of 55 mm were cut out. For this test piece, using a viscoelasticity measuring device (ARES, manufactured by TA Instruments), DMA measurement was carried out in the temperature range of 40 to 250 °C under the conditions of a torsional vibration frequency of 1.0 Hz and a heating rate of 5.0 °C / min, and the glass transition temperature was read. The glass transition temperature was the temperature at the intersection of the tangent line of the curve showing the transition of the storage modulus G' with respect to temperature in the region where the target cured product is in a glass state and the tangent line of the curve in the region where the target cured product is in a transition state.

[0063] (3) Weather resistance test of the resin cured product From the resin cured product with a thickness of 1 mm prepared according to the above <Method for Producing Resin Cured Product>, a test piece with a width of 37 mm and a length of 68 mm was cut out. Using an accelerated weather resistance tester (Super Xenon Weather Meter SX-75, manufactured by Suga Test Instruments Co., Ltd.) for this test piece, the intensity was 180 W / m 2 , with a black panel temperature of 63°C, a humidity of 50% RH, and irradiation for 102 minutes without water injection, and an intensity of 180 W / m 2 , with a tank temperature of 28°C, a humidity of 99% RH, and irradiation for 18 minutes while injecting water, were used as one cycle, and a weather resistance test was repeated 12 times (i.e., 24 hours).

[0064] The evaluation of weather resistance was performed by measuring the color difference (ΔE) of the cured product before and after the weather resistance test using a multi-light source spectrophotometer (MSC-P, manufactured by Suga Test Instruments Co., Ltd.). The tristimulus values (L * , a * , b * ) were obtained by the reflection method under the optical conditions of D65 light source, 10° field of view, and d / 8 excluding regular reflection light, and the color difference (ΔE) was calculated by the above formula (I) using the differences in tristimulus values (ΔL * , Δa * , Δb * ) before and after the weather resistance test.

[0065] (4) Viscosity measurement of the epoxy resin composition The viscosity of the epoxy resin composition was measured using a dynamic viscoelasticity apparatus (ARES-2KFRTN1-FCO-STD, manufactured by TA Instruments). Using parallel plates with a diameter of 25 mm for the upper measurement jig and a diameter of 40 mm for the lower measurement jig, after setting the epoxy resin composition so that the distance between the upper and lower jigs was 1 mm, it was measured in torsion mode (measurement frequency: 0.5 Hz). The temperature was raised from 40°C to 60°C at a rate of 1°C / min, and when the viscosity at 50°C was 1 to 10,000 Pa·s, it was marked as "〇", and when it was less than 1 Pa·s or greater than 10,000 Pa·s, it was marked as "×" and entered in the column of "Properties of Uncured Resin" in the table.

[0066] (5) Weather resistance test of fiber-reinforced composite materials Align the fiber directions of the prepregs produced by the above <Method for producing prepreg>, stack 4 plies, heat in an autoclave under a pressure of 0.7 MPa from 30 °C at a rate of 1.7 °C / min to 90 °C, hold at 90 °C for 60 minutes, then heat to 135 °C at a rate of 2.0 °C / min and mold at 135 °C for 120 minutes to produce a woven CFRP plate with a thickness of 1 mm. Cut out test pieces with a width of 37 mm and a length of 68 mm from the woven CFRP plate. After conducting a weather resistance test on this test piece under the same conditions as in <Various evaluation methods> "(3) Weather resistance test of resin cured product", arrange the test pieces before and after the weather resistance test side by side and conduct a hearing on the color difference for 10 subjects. When 8 or more of the 10 subjects answered "There is no color change" or "I can't tell the color change", it was marked as "〇", and when 3 or more subjects answered "There is a color change", it was marked as "×".

[0067] <Example 1> Among the epoxy resins, 50 parts by mass of "TETRAD (registered trademark)"-X as component [A], 30 parts by mass of "EPICLON (registered trademark)" N-695 as component [D], 20 parts by mass of "EPICLON (registered trademark)" 830 as other epoxy resin (component [E]), 9.7 parts by mass of DICY7 as component [B]: dicyandiamide, and 1 part by mass of DCMU99 as a curing accelerator were used, and a resin composition was prepared according to the above <Method for preparing resin composition>.

[0068] From the obtained resin composition, a resin cured product was prepared according to <Method for producing resin cured product>. When the flexural strength, flexural modulus, glass transition temperature, and weather resistance (color difference ΔE) of this resin cured product were measured according to <Various evaluation methods>, the flexural strength was 190 MPa, the flexural modulus was 4.2 GPa, the glass transition temperature was 151 °C, and the color difference ΔE was 8.1. The physical properties and weather resistance of the resin cured product were good.

[0069] When the obtained resin composition was measured according to "(4) Viscosity measurement of epoxy resin composition" in <Various evaluation methods>, the viscosity of the resin composition was good.

[0070] In addition, a prepreg was prepared from the obtained resin composition according to the <Method for Producing Prepreg>, and when measured according to the “(5) Weather Resistance of Fiber Reinforced Composite Material” of the <Various Evaluation Methods>, the weather resistance of the fiber reinforced composite material was good.

[0071] <Examples 2 to 11> Resin compositions, resin cured products, and prepregs were produced in the same manner as in Example 1, except that the composition was changed as shown in Table 1. For each example, the flexural strength, flexural modulus, glass transition temperature, weather resistance (color difference ΔE) of the resin cured product, the viscosity of the resin composition, and the weather resistance of the fiber reinforced composite material measured according to the <Various Evaluation Methods> were as shown in Table 1, and all were good.

[0072] <Comparative Example 1> The composition shown in Table 1 was used, and resin compositions, resin cured products, and prepregs were produced in the same manner as in Example 1. The physical property evaluation results are shown together in Table 1 (the same applies to subsequent comparative examples). The weather resistance of the resin cured product, the viscosity of the resin composition, and the weather resistance of the fiber reinforced composite material were good. However, in the resin composition, the content of component [A] was less than 15 parts by mass in 100 parts by mass of the total epoxy resin and did not satisfy condition (1), so the flexural strength, flexural modulus, and glass transition temperature of the resin cured product were lower than those of Example 11.

[0073] <Comparative Example 2> The composition shown in Table 1 was used, and resin compositions, resin cured products, and prepregs were produced in the same manner as in Example 1. The flexural strength, flexural modulus, glass transition temperature, and viscosity of the resin composition of the resin cured product were good. However, in the resin composition, the content of component [C] exceeded 10 parts by mass in 100 parts by mass of the total epoxy resin and did not satisfy condition (2), so the weather resistance of the resin cured product and the weather resistance of the fiber reinforced composite material were inferior to those of Example 1 and Example 7.

[0074] <Comparative Example 3> Using the composition shown in Table 1, a resin composition, a cured resin, and a prepreg were prepared in the same manner as in Example 1. The flexural strength, flexural modulus, glass transition temperature of the cured resin, and the viscosity of the resin composition were good. However, in the resin composition, since the content of Component [C] exceeded 10 parts by mass per 100 parts by mass of the total epoxy resin and did not satisfy condition (2), the weather resistance of the cured resin and the weather resistance of the fiber-reinforced composite material were inferior to those of Example 1.

[0075] <Comparative Example 4> Using the composition shown in Table 1, a resin composition, a cured resin, and a prepreg were prepared in the same manner as in Example 1, except for the points shown in <Preparation method of resin composition>. The flexural strength, flexural modulus, glass transition temperature of the cured resin, and the viscosity of the resin composition were good. However, since "Seikacure (registered trademark)"-S was used as another curing agent without using Component [B], the weather resistance of the cured resin and the weather resistance of the fiber-reinforced composite material were inferior to those of Example 1.

[0076] <Comparative Example 5> Using the composition shown in Table 1, a resin composition, a cured resin, and a prepreg were prepared in the same manner as in Example 1, except for the points shown in <Preparation method of resin composition>. The weather resistance of the cured resin, the viscosity of the resin composition, and the weather resistance of the fiber-reinforced composite material were good. However, since "Cureduct (registered trademark)" P-0505 was used as another curing agent without using Component [B], the flexural strength, flexural modulus, and glass transition temperature of the cured resin were lower than those of Example 9. <Comparative Example 6> Using the composition shown in Table 1, a resin composition, a cured resin, and a prepreg were prepared in the same manner as in Example 1, except for the points shown in <Preparation method of resin composition>. The glass transition temperature, weather resistance of the cured resin, the viscosity of the resin composition, and the weather resistance of the fiber-reinforced composite material were good. However, since "ANCAMINE (registered trademark)" 2049 was used as another curing agent without using Component [B], the flexural strength and flexural modulus of the cured resin were lower than those of Example 9.

[0077]

Table 1

Claims

1. A prepreg comprising reinforcing fibers and a resin composition, The resin composition contains the following component [A] and component [B], And the prepreg satisfies the following conditions (1) and (2): Component [A]: Xylenediamine type epoxy resin Component [B]: Dicyandiamide Condition (1): The content of component [A] is 15 parts by mass or more based on 100 parts by mass of the total epoxy resin. Condition (2): The following component [C] is not contained, or if it is contained, its content is 10 parts by mass or less based on 100 parts by mass of the total epoxy resin. Component [C]: Amine-type epoxy resin in which a glycidylamino group is bonded to an aromatic ring

2. The prepreg according to claim 1, further comprising 10 to 50 parts by mass of a novolac-type epoxy resin, based on 100 parts by mass of the total epoxy resin.

3. 3. The prepreg according to claim 2, wherein the content of component [A] in condition (1) is 25 parts by mass or more, and component [D]: a novolac-type epoxy resin is contained in an amount of 20 to 50 parts by mass, relative to 100 parts by mass of the total epoxy resins.

4. The prepreg according to claim 1, which does not contain the component [C].

5. A 1 mm thick cured resin product obtained from the resin composition was exposed to radiation at a dose of 16 MJ / m ２ 2. The prepreg according to claim 1, wherein when the cured resin is irradiated with UV light, a change in color (color difference ΔE) between before and after the UV irradiation is 10 or less.

6. A fiber-reinforced composite material obtained by molding the prepreg according to any one of claims 1 to 5.

7. A tubular body made of a fiber-reinforced composite material, which is formed by molding the prepreg according to any one of claims 1 to 5.

8. A golf club shaft comprising the tubular body made of the fiber-reinforced composite material according to claim 7.

9. A fishing rod comprising the tubular body made of the fiber-reinforced composite material according to claim 7.

10. An automobile structural member, comprising the fiber-reinforced composite material according to claim 6.

11. An exterior member comprising the fiber-reinforced composite material according to claim 6.

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