JP2008088342A - Epoxy resin composition and method for producing fiber-reinforced composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition excellent in molding property and usable in filament winding and pultrusion method and to provide a fiber-reinforced composite material excellent in mechanical property at a high temperature. <P>SOLUTION: The invention relates to the liquid epoxy resin composition for forming fiber-reinforced composite material comprising an epoxy resin (A) comprising a compound selected from cycloaliphatic epoxy compounds and triglycidyl aminophenol, a hardening agent for epoxy resin (B) comprising at least one compound selected from the group consisting of nadic acid anhydrides and a polycarboxylic acid anhydride containing two or more anhydride groups in the molecule, and (C) a hardening accelerator including an imidazole derivative, wherein the composition has 50-500 mPa s of viscosity at 50°C. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an epoxy resin composition and a fiber-reinforced composite material that can be widely used in the fields of aviation / space, transportation equipment / industrial machinery, civil engineering / architecture, sports / leisure.

  Fiber reinforced composite materials consisting of glass fibers, carbon fibers and aramid fibers and other matrix resins such as unsaturated polyester resins, vinyl ester resins, epoxy resins, phenol resins, cyanate resins and bismaleimide resins are lightweight. However, because of its excellent mechanical properties such as strength and rigidity, it has been widely applied in the aerospace field, transportation equipment / industrial machinery field, civil engineering / architecture field, sports / leisure field and the like. Among these, epoxy resins having excellent heat resistance, elastic modulus and chemical resistance and having a small curing shrinkage are most often used as matrix resins for fiber reinforced composite materials.

  Various methods such as a prepreg method, a hand lay-up method, a filament wiping method, a pultrusion method, and an RTM method (resin transfer molding method) are applied to the production of the fiber reinforced composite material. Among these, the filament winding method and the pultrusion method are useful as methods capable of producing a fiber-reinforced composite material in a large amount at a relatively low cost, although the shapes that can be produced are limited.

Conventionally, as an epoxy resin used for the filament winding method and the pultrusion method, there are many examples of curing a low-viscosity liquid epoxy resin with an acid anhydride curing agent or an amine curing agent, and in recent years, heat resistance has been improved in each application field. Responding to demands, polyfunctional epoxy resins and resins using aromatic amine curing agents are being studied, but it is difficult to achieve both heat resistance and moldability, and both the filament winding method and the pultrusion method are used. It was not a usable resin. (For example, Patent Document 1 and Patent Document 2)
Japanese Patent No. 3531845 Japanese Patent Laid-Open No. 5-117212

  An object of the present invention is to provide an epoxy resin composition that is excellent in moldability and can be used for both the filament winding method and the pultrusion method, and a fiber-reinforced composite material having excellent mechanical properties at high temperatures using the same. It is.

In order to solve this problem, the present invention employs the following means.
That is,
(1) (A) epoxy resin containing a compound selected from cycloaliphatic epoxy compounds and triglycidylaminophenol, (B) nadic acid anhydrides and polyhydric acid anhydrides having two or more acid anhydride groups in one molecule An epoxy resin curing agent containing at least one compound selected from the group consisting of a product, (C) a curing accelerator containing an imidazole derivative, and a viscosity at 50 ° C. of 50 mPa · s to 500 mPa · s. A liquid epoxy resin composition for molding a fiber-reinforced composite material.
(2) The aligned reinforcing fiber bundle is continuously passed through the impregnation tank of the liquid epoxy resin composition for molding a fiber reinforced composite material described in (1), and the fiber epoxy resin composition is impregnated into the fiber bundle. And then winding the mandrel, then curing the resin on the mandrel, and then drawing out the mandrel.
(3) The aligned reinforcing fiber bundle is continuously passed through the impregnation tank of the liquid epoxy resin composition for molding a fiber reinforced composite material as described in (1) above, and continuously with a squeeze die and a heating die by a tension machine. The manufacturing method of the fiber reinforced composite material which has the process of making it harden | cure while performing pultrusion.

ADVANTAGE OF THE INVENTION According to this invention, the epoxy resin composition which is excellent in a moldability and can be used for both a filament winding method and a pultrusion method, and the fiber reinforced composite material excellent in the mechanical property at high temperature using the same are obtained.

  The epoxy resin composition of the present invention comprises (A) an epoxy resin containing a compound selected from cycloaliphatic epoxy compounds and triglycidylaminophenol, (B) nadic acid anhydrides, and two acid anhydride groups in one molecule. An epoxy resin curing agent containing at least one compound selected from the group consisting of polyhydric acid anhydrides, and (C) a curing accelerator containing an imidazole derivative, and having a viscosity at 50 ° C. of 50 mPa · s or more. The liquid epoxy resin composition for fiber-reinforced composite materials is 500 mPa · s or less.

  The component (A) in the present invention is an epoxy resin containing a compound selected from a cycloaliphatic epoxy compound and triglycidylaminophenol. By using a compound selected from these cycloaliphatic epoxy compounds and triglycidylaminophenol, a cured product having low viscosity, excellent moldability, and high heat resistance can be obtained.

  As long as the component (A) in the present invention contains a compound selected from a cycloaliphatic epoxy compound and triglycidylaminophenol, the amount thereof is not limited, but it is contained in the epoxy resin by 15% by weight or more. It is more preferable that it is contained in an amount of 25% by weight or more. Increasing the content is preferable because the heat resistance can be further improved.

  Here, the cycloaliphatic epoxy compound means an epoxy resin having 1,2-epoxycycloalkane as a partial structure. Specific examples include vinylcyclohexane diepoxide (ERL-4206, manufactured by Dow Chemical Co., Ltd.), 3,4-epoxycyclohexylmethyl-3,4-epoxy-cyclohexanecarboxylate (“Celoxide, manufactured by Daicel Chemical Industries, Ltd.) (Registered trademark 2021P), 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-m-dioxane (ERL-4234 manufactured by Dow Chemical Co., Ltd.), bis ( 3,4-epoxycyclohexyl) adipate (ERL-4299 manufactured by Dow Chemical Co., Ltd.) and the like, but are not limited thereto.

  As triglycidylaminophenol, triglycidyl-p-aminophenol (“jER” (registered trademark) 630 manufactured by Japan Epoxy Resin Co., Ltd.), triglycidyl-m-aminophenol (Huntsman Advanced Materials ( "Araldite" (registered trademark) MY0600) manufactured by Co., Ltd., but not limited thereto.

  Moreover, you may mix | blend the epoxy resin other than the above with the structural component (A) in this invention. Specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, diglycidyl anilines, tetraglycidyl diaminodiphenyl methane, Glycidylamine type epoxy resins such as tetraglycidyl-m-xylenediamine can be used, but are not limited thereto.

  Component (B) in the present invention is a cured epoxy resin containing at least one compound selected from the group consisting of nadic acid anhydrides and polyhydric acid anhydrides having two or more acid anhydride groups in one molecule. It is an agent. By using at least one compound selected from the group consisting of these acid anhydrides and polyhydric acid anhydrides having two or more acid anhydride groups in one molecule, low viscosity and excellent moldability, A cured product having high heat resistance is obtained.

  The component (B) in the present invention includes at least one compound selected from the group consisting of nadic acid anhydrides and polyhydric acid anhydrides having two or more acid anhydride groups in one molecule. The amount thereof is not limited, but it is preferably 15% by weight or more, more preferably 25% by weight or more in the epoxy resin curing agent. Increasing the content can further improve the heat resistance.

  Here, nadic acid anhydride means an acid anhydride having norbornene or norbornane as a partial structure. Specific examples include nadic acid anhydride (“Kayahard” (registered trademark) CD manufactured by Nippon Kayaku Co., Ltd.), methyl nadic acid anhydride (“Kayahard” (registered trademark) MCD manufactured by Nippon Kayaku), norbornane-2,3. -Dicarboxylic acid anhydride, methylnorbornane-2,3-dicarboxylic acid anhydride, etc. are mentioned, but it is not limited to these.

  Specific examples of the compound selected from polyhydric acid anhydrides having two or more acid anhydride groups in one molecule include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic acid dioxygen. Examples thereof include, but are not limited to, anhydrides, glycerol bis (anhydrotrimellitate) monoacetate, ethylene glycol bis (anhydrotrimellitate), butanetetracarboxylic dianhydride, and the like.

  Moreover, you may mix | blend the epoxy resin hardening | curing agent other than the above with the structural component (B) in this invention. The curing agent that can be blended is not limited as long as it is a compound that cures an epoxy resin, such as an amine curing agent, a phenol curing agent, and an acid anhydride curing agent. A curing agent is preferred. Specific examples include, but are not limited to, phthalic anhydride, succinic anhydride, maleic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and the like. It is not a thing.

  The component (C) in the present invention is a curing accelerator containing an imidazole derivative. By using these imidazole derivatives, the balance between curability and viscosity stability can be achieved, and excellent heat resistance and moldability can be obtained.

  Here, the imidazole derivative means a compound having an imidazole ring in the molecule. Specifically, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, Examples include 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-aminoethyl-2-methylimidazole, and the like. However, it is not limited to these. Among the imidazole derivatives, imidazole derivatives having a substituent at the 1-position are excellent in viscosity stability and are particularly preferably used. 1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1 -Cyanoethyl-2-methylimidazole, 1-aminoethyl-2-methylimidazole and the like are preferable.

  The compounding quantity of the component (C) in this invention is 0.1-10 weight part normally with respect to 100 weight part of component (A), Preferably it exists in the range of 0.2-5 weight part. When the amount is less than 0.1 parts by weight, curing may be insufficient. When the amount is more than 10 parts by weight, the pot life may be reduced or the mechanical properties may be deteriorated.

  Moreover, the epoxy resin composition of this invention can also contain surfactant, an internal mold release agent, a pigment | dye, a flame retardant, antioxidant, a ultraviolet absorber etc. in additives other than the said component.

  The epoxy resin composition in the present invention has a viscosity at 50 ° C. of 50 mPa · s or more and 500 mPa · s or less in order to be usable for both the filament winding method and the pultrusion method. If the viscosity is lower than 50 mPa · s, the resin is not sufficiently retained in the reinforcing fiber bundle at the time of molding, and if the viscosity is higher than 500 mPa · s, the resin is not sufficiently impregnated in the reinforcing fiber bundle at the time of molding. To do.

  The viscosity of the epoxy resin composition in the present invention is determined according to a measuring method using a cone-plate type rotational viscometer in ISO 2884-1.

  As the reinforcing fiber used for the fiber-reinforced composite material in the present invention, glass fiber, aramid fiber, carbon fiber, boron fiber, basalt fiber, Tyranno fiber, PBO fiber, etc. are preferable, but particularly excellent in strength and elastic modulus. Therefore, it is preferable to use carbon fiber. The carbon fiber can be used regardless of whether it is PAN-based or pitch-based, and preferably has a tensile elastic modulus of 150 GPa or more and 950 GPa or less in a strand tensile test according to the method described in JIS R7601 (1986).

  The liquid epoxy resin composition for molding a fiber reinforced composite material according to the present invention has a viscosity in a region excellent in impregnation with respect to a fiber bundle in the filament winding molding method, and its change with time is small, so a general filament winding molding method is used. It can be preferably used in a molding method in which a fiber-reinforced composite material is obtained by heating and curing after molding.

  As a general filament winding molding method, first, a bundle of reinforcing fibers is arranged, and this is continuously passed through an impregnation tank of an epoxy resin composition, so that the fiber bundle is impregnated with a resin, and a mandrel is made in the axial direction. And spirally wound at various angles. Next, after wrapping the surface with a surface layer material or the like to squeeze out excess resin, the resin is cured on a mandrel using a curing furnace or the like, and a molded product is extracted from the mandrel to obtain a fiber-reinforced composite material.

  Here, the impregnation tank is preferably kept at 10 to 80 ° C. More preferably, it is 20-60 degreeC. When the temperature of the impregnation tank is 80 ° C. or higher, the viscosity stability of the epoxy resin composition may be deteriorated. Further, when the temperature of the impregnation tank is 10 ° C. or less, the impregnation of the fibers may be deteriorated.

  Note that the above shows an example of the filament winding method, and the present invention is not limited to this.

  Here, Wf of the obtained fiber reinforced composite material can be obtained by measuring the weight before and after combustion based on the combustion method described in JIS K7075 (1991).

  The fiber reinforced composite material molded by the filament winding molding method of the present invention is lightweight, has excellent mechanical properties such as strength and elastic modulus, and is excellent in heat resistance. Therefore, a propeller shaft for an automobile, a CNG tank, a fly It is suitable for sports and leisure products such as various industrial machine parts such as wheels, golf shafts and fishing rods.

  The liquid epoxy resin composition for molding a fiber reinforced composite material according to the present invention has a viscosity in a region excellent in impregnation with respect to a fiber bundle in the pultrusion molding method, and since its change with time is small, a general pultrusion molding method is performed. It can be preferably used in a molding method in which a fiber reinforced composite material is obtained by heat-curing in parallel with pultrusion or after pultrusion.

  As a general pultrusion method, reinforcing fibers are continuously passed through an impregnation tank of an epoxy resin composition, and are cured while being continuously pultruded by a tension machine through a squeeze die and a heating mold. Further, it is cured in an after cure oven to obtain a fiber reinforced composite material. The above shows an example of the pultrusion method, and the present invention is not limited to this.

  The impregnation tank is preferably maintained at 10 to 80 ° C. More preferably, it is 20-60 degreeC. When the temperature of the impregnation tank is 80 ° C. or higher, the viscosity stability of the epoxy resin composition may be deteriorated. Further, when the temperature of the impregnation tank is 10 ° C. or less, the impregnation of the fibers may be deteriorated.

  The temperature of the mold is preferably 100 to 250 ° C. More preferably, it is 120-220 degreeC. If it is 100 ° C. or lower, curing failure in the mold may occur, and if it is 250 ° C. or higher, the decomposition reaction of the epoxy resin composition may occur.

  The residence time in the mold is preferably 30 seconds to 5 minutes. If the residence time is 30 seconds or less, curing in the mold is insufficient and the appearance may be deteriorated. If it is 5 minutes or longer, it may be completely cured in the mold and may not be pulled out.

  After-curing may be performed to improve heat resistance or complete the reaction of the epoxy group. After curing, after passing through the mold, after-curing oven may be installed and cured online, or after winding, it may be cured in the oven. The after-curing temperature is preferably 130 to 220 ° C. from the viewpoint of heat resistance and physical properties. More preferably, it is 140-200 degreeC. If it is 130 ° C. or lower, the glass transition temperature of the resin is not exceeded, so that the reaction may not proceed easily, and it may take a long time for after-curing and productivity may be lowered. On the other hand, if it is 220 ° C. or higher, it may be deformed by heat. The after-curing time is preferably 5 minutes to 10 hours depending on the curing temperature. When the time is shorter than 5 minutes, the reaction may not be completed sufficiently. When the time is longer than 10 hours, the productivity is deteriorated.

  The weight content (Wf) of the carbon fiber of the pultruded product of the present invention is preferably 50 to 90% in order to sufficiently draw out the characteristics of light weight, high strength and high elastic modulus. More preferably, it is 60 to 85%. When it is 50% or less, it is difficult to obtain the light weight, high strength, and high modulus characteristics of the present invention, and when it is 90% or more, the resin is not sufficiently impregnated into the reinforcing fiber bundle and voids are generated inside. Sometimes.

  Here, Wf of the obtained fiber reinforced composite material can be obtained by measuring the weight before and after combustion based on the combustion method described in JIS K7075 (1991).

  Carbon fiber reinforced composite materials formed by pultrusion molding are lightweight, have excellent mechanical properties such as strength and elastic modulus, and have excellent heat resistance. It is suitable for such as.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.
<Resin raw material>
Epoxy resin “Celoxide” (registered trademark) 2021P: 3,4-epoxycyclohexylmethyl-3,4-epoxy-cyclohexanecarboxylate, ERL4299 manufactured by Daicel Chemical Industries, Ltd .: bis (3,4-epoxycyclohexyl) adipate, "JER" (registered trademark) 630 manufactured by Dow Chemical Co., Ltd .: triglycidyl-p-aminophenol, "jER" (registered trademark) 828 manufactured by Japan Epoxy Resin Co., Ltd .: bisphenol A type epoxy resin, Japan Epoxy Resin Co., Ltd. Acid anhydride curing agent “Kayahard” (registered trademark) MCD: Methyl nadic acid anhydride, “Rikacid” (registered trademark) MTA-15 manufactured by Nippon Kayaku Co., Ltd .: “glycerol bisanhydro trimellitate /“ Rikacid "(registered trademark) MH700 = 33/67 (heavy Ratio), Shinnippon Rika Co., Ltd. pyromellitic dianhydride: Sigma Aldrich Japan Co., Ltd. “Rikacid” (registered trademark) MH700: methylhexahydrophthalic anhydride / hexahydrophthalic anhydride = 70 / 30 (weight ratio) mixture, manufactured by Shin Nippon Rika Co., Ltd., curing accelerator “jER Cure” (registered trademark) EMI24: 2-ethyl-4-methylimidazole, “JER Cure” manufactured by Japan Epoxy Resin Co., Ltd. (Registered Trademark) BMI12: 1-benzyl-2-methylimidazole, Japan Epoxy Resin Co., Ltd. TPP: Triphenylphosphine, Hokuko Chemical Industries Co., Ltd. <Reinforced fiber>
“Torayca” (registered trademark) T700SC-24K: carbon fiber, manufactured by Toray Industries, Inc.

(1) Preparation of resin composition A curing accelerator was added to the curing agent shown in Table 1, and the mixture was heated to 50 ° C and dissolved. Next, this solution was kept at 50 ° C., and an epoxy resin heated to 50 ° C. was added to prepare an epoxy resin composition.

(2) Viscosity measurement of resin composition According to a measurement method using a cone-plate type rotational viscometer in ISO 2884-1, an epoxy resin composition was prepared, and adjusted for 4 hours immediately after adjustment and in a thermostat at 50 ° C. The viscosities that were allowed to stand were each measured at 50 ° C. As the apparatus, TVE-30H type manufactured by Toki Sangyo Co., Ltd. was used. Here, the rotor was 1 ° 34 ′ × R24, and the sample amount was 1 cm ³ .

(3) Fabrication of filament winding molded product (propeller shaft) This will be described with reference to FIGS. Three filaments of Toray Industries, Inc., “Torayca (registered trademark)” T700SC-24K are aligned, and the resin composition prepared in (1) is heated to 50 ° C. and impregnated in an impregnation tank, and then subjected to a filament winding method. After forming a spiral wound layer 2a 0.2mm of 85 ° on the inner layer with respect to its axial direction on a φ70mm mandrel, the main layer 2b is spirally wound with a thickness of 1mm at ± 12 ° and then at a thickness of ± 45 °. After spirally winding 0.5 mm and a thickness of 1 mm at ± 12 °, a spirally wound layer 2c of 0.2 mm having an outermost layer of 85 ° was implemented. The main layer is composed of a total of 2.9 mm. In addition, in a portion corresponding to a length of 110 mm at both ends of the main body cylinder, which is a fitting portion, a thickness constituted by ± 83 ° with respect to the axial direction is provided in order to improve the joint strength with the joint. A reinforcing layer 2d of 2.5 mm was formed. The reinforcing layer 2d is formed of a straight portion having a thickness of 2.5 mm and an axial length of 60 mm and a tapered portion having a length of 50 mm toward the axial center.

  Thereafter, curing was performed in a curing furnace. The curing temperature was 100 ° C. × 2 hr + 200 ° C. × 4 hr, and an FRP cylinder 2 was obtained.

(4) Glass transition temperature of filament winding molded product The glass transition temperature of the cured product of the molded product is measured by using a differential calorimeter (DSC) to determine the intermediate temperature determined based on JIS K7121 (1987). It was.

(5) Measurement of torsional strength of filament wound molded article This will be described with reference to FIGS. The metal joint 3 to be joined to both ends of the FRP cylindrical body 2 has a serration portion 3a. The serration used was a serration with a pitch of about 2 mm, a tooth height of 0.9 mm, a tip R of 0.04 mm, and a tooth tip angle of 90 degrees, and the outer diameter was processed to 74.45 mm. Therefore, it has a press-fitting allowance of 0.40 mm in diameter. The metal joint 3 was press-fitted and joined to the FRP cylindrical body 2 to form a propeller shaft 1 and then evaluated by a torsion tester.
FIG. 5 shows an overview of the torsion test. The torsion test FRP main body cylinder 4 in which the torsion test joints 4a and 4b are press-fitted at both ends is fixed to the flange portion of the torsion tester. At this time, one of the movable part flanges 5a has a rotational drive part by hydraulic pressure, and a torque load can be applied to the specimen. The other fixed portion flange 5b is fixed to the tester base, and torque can be detected from the load cell 5c connected to the flange portion. In addition, since the test temperature is important in the present invention, the torsion test was carried out after adjusting and holding at a predetermined temperature using the thermostatic bath 6 shown in FIG. The ambient temperature was detected from the thermometer 6a in the figure. The test speed and temperature setting during the torsion test are set by the control device shown in FIG.

(6) Void observation molded product of filament winding molded product was cut, and the cross-section was appropriately polished with water-resistant paper # 240, 400, 800, and photographed with a digital microscope (CCD) at a magnification of 50 times. Measure the area ratio of the normal part and void (gap part) of the photographed cross section, ◎ for those with a void ratio of less than 1%, ○ for 1-3%, △ 5% for 3-5% The thing exceeding was judged as x.

(7) Production of pultruded product The resin composition prepared in (1) was allowed to stay in an impregnation tank at 25 ° C. for 2 hours. 112 carbon fibers “Torayca (registered trademark)” T700SC-24K manufactured by Toray Industries, Inc. are passed through the impregnation tank containing the resin composition as impregnated resin, and then impregnated with the resin. And cured at 150 ° C. for 15 minutes to obtain a fiber-reinforced composite material having a width of 100 mm and a thickness of 1.4 mm.

(8) Glass transition temperature of pultruded molded product The glass transition temperature of the cured product of the molded product is measured by using a differential calorimeter (DSC) to determine the intermediate temperature determined based on JIS K7121 (1987) as the glass transition temperature. did.

(9) Tensile strength measurement of pultruded molded product A test piece having a length of 200 mm and a width of 12.5 mm is cut out from the molded product produced in (7) in a fiber direction, and a constant temperature bath is used according to JIS K7073 (1988). After adjusting the temperature to 150 ° C., a tensile test was performed at a crosshead speed of 1 mm / min to calculate the tensile strength. The tensile strength was normalized to 80% Wf (fiber weight content).

(10) Void observation molded product of pultruded product was cut, and the cross section was appropriately polished with water-resistant paper # 240, 400, 800, and photographed with a digital microscope (CCD) at a magnification of 50 times. Measure the area ratio of the normal part and void (gap part) of the photographed cross section, ◎ for those with a void ratio of less than 1%, ○ for 1-3%, △ 5% for 3-5% The thing exceeding was judged as x.

(11) Fiber weight content of pultruded product By measuring the weight before and after combustion of the carbon fiber reinforced composite material prepared by the method of (5) above using the combustion method described in JIS K7075 (1991). The weight content was determined.

  By comparing Examples 1 to 7 and Comparative Examples 1 to 3, the liquid epoxy resin composition for fiber-reinforced composite material of the present invention has low viscosity and excellent viscosity stability, and is suitable for filament winding molding and pultrusion molding. It can be seen that the fiber-reinforced composite material produced by these methods is excellent in mechanical properties at high temperatures.

  The resin compositions of Examples 1 to 7 each have a low viscosity at 50 ° C. both immediately after preparation and after standing for 4 hours, and are excellent in filament winding moldability and pultrusion moldability. Moreover, the filament winding molded products of Examples 1 to 7 have high Tg, excellent 150 ° C. torsional strength, and few voids. Furthermore, the pultruded molded products of Examples 1 to 7 have high Tg, excellent 150 ° C. tensile strength, and few voids. In addition, the resin compositions of Examples 2 to 7 using imidazole having a substituent at the 1-position as the curing accelerator have a small viscosity after standing for 4 hours and a rate of change in viscosity immediately after the preparation, and the moldability and each molding It is particularly excellent because of the small number of voids.

  On the other hand, in Comparative Example 1 which does not contain the epoxy resin corresponding to the component (A) of the present invention, the viscosity is high and the moldability is inferior, each molded product has a low Tg, and the 150 ° C. torsional strength and tensile strength are inferior. The amount generated is also large.

  In Comparative Example 2 not containing the curing agent corresponding to the component (B) of the present invention, the viscosity is low and the moldability is excellent, but the Tg of the molded product is low, and the torsional strength and tensile strength at 150 ° C. are low. Very inferior.

  Furthermore, Comparative Example 3 which does not contain a curing accelerator corresponding to the component (C) of the present invention has a large viscosity change rate, a high viscosity after being left for 4 hours, and a slightly poor moldability. Also, the Tg of the molded product is low, and the torsional strength and tensile strength at 150 ° C. are slightly inferior.

It is a schematic sectional drawing which shows the principal part of an example of the propeller shaft of this invention. It is a schematic sectional drawing which shows an example of a structure of the main body cylinder made from FRP of the propeller shaft of this invention. It is a perspective view which shows the mode of a twist test.

Explanation of symbols

1 Propeller shaft 2 FRP cylinder 2a Inner layer
2b Main layer 2c Outer layer
2d reinforcement layer 3 metal joint 3a serration part 4 torsion test FRP main body cylinder 4a, b torsion test joint 5 torsion tester 5a movable part flange 5b fixed part flange 5c load cell 5d rotating part 6 thermostatic chamber 6a temperature detection part 7 hydraulic pressure Pump 8 controller

  ADVANTAGE OF THE INVENTION According to this invention, the epoxy resin composition which is excellent in a moldability and can be used for both a filament winding method and a pultrusion method, and the fiber reinforced composite material excellent in the mechanical property at high temperature using the same are obtained. Among them, it is suitable for automobile parts such as propeller shafts, industrial machine parts such as robot arms, and repair / reinforcing agents for civil engineering buildings.

Claims (3)

  From the group consisting of epoxy resin (A) containing a compound selected from cycloaliphatic epoxy compounds and triglycidylaminophenol, nadic acid anhydrides and polyhydric acid anhydrides having two or more acid anhydride groups in one molecule A fiber reinforced composite comprising an epoxy resin curing agent (B) containing at least one selected compound and a curing accelerator (C) containing an imidazole derivative, and having a viscosity at 50 ° C. of 50 to 500 mPa · s. Liquid epoxy resin composition for material molding.   The aligned reinforcing fiber bundle is continuously passed through the impregnation tank of the liquid epoxy resin composition for molding a fiber reinforced composite material according to claim 1 to impregnate the fiber bundle with the liquid epoxy resin composition, A method for producing a fiber-reinforced composite material, after winding, curing a resin on a mandrel, and then extracting the mandrel.   The aligned reinforcing fiber bundle is continuously passed through the impregnation tank of the liquid epoxy resin composition for molding a fiber reinforced composite material according to claim 1, and continuously drawn by a pulling machine through a squeeze die and a heating die. The manufacturing method of the fiber reinforced composite material which has the process hardened while doing.

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