JP5028903B2 - Pultruded fiber reinforced composite material - Google Patents

Description

  The present invention relates to an epoxy resin composition and a fiber-reinforced composite material molded article that are suitably used in an epoxy resin pultruded molded article.

  Fiber reinforced composite materials composed of reinforced fibers and matrix resins can be designed using the advantages of reinforced fibers and matrix resins, so the applications have been expanded widely in aerospace, sports, general industrial fields, etc. Yes.

  As the reinforcing fiber, glass fiber, aramid fiber, carbon fiber, boron fiber or the like is used. As the matrix resin, either a thermosetting resin or a thermoplastic resin is used, but a thermosetting resin that can be easily impregnated into the reinforcing fiber is often used. As the thermosetting resin, epoxy resin, unsaturated polyester resin, vinyl ester resin, phenol resin, maleimide resin, cyanate resin and the like are used.

  Methods such as a prepreg method, a hand lay-up method, a filament winding method, a pultrusion method (pulling molding method), and an RTM (Resin Transfer Molding) method are applied to the production of a fiber reinforced composite material.

  Among them, the pultrusion molding method is such that a reinforcing fiber is continuously passed through an impregnation tank filled with a liquid thermosetting resin composition, impregnated with the thermosetting resin composition, and pulled through a squeeze die and a heating die. This is a molding method in which the fiber-reinforced composite material can be continuously molded while being drawn and cured continuously.

  In the pultrusion molding, the resin composition needs to have a sufficiently low viscosity so that the reinforcing fibers can be quickly impregnated in the impregnation tank, and the stability of the viscosity is important from the viewpoint of long-term continuous productivity. In addition, in order to enable high-speed production, it is also necessary to achieve both high curability and rapid curing of the resin in the mold.

  As a resin composition for pultrusion molding, a composition comprising an epoxy resin, an acid anhydride, and imidazole is known. (For example, patent document 1) However, since the viscosity of the epoxy resin to be used is high viscosity, since the viscosity of a resin composition becomes high and the impregnation property to a reinforced fiber worsens, it is hard to express mechanical characteristics. There is a drawback that the surface quality of the molded product may be deteriorated.

In order to solve this problem, an example in which a low-viscosity epoxy resin is used for pultrusion molding is also known. (For example, Patent Document 2) In this example, the epoxy resin to be used has a low viscosity but is multifunctional, so that there is a problem that the reactivity is high, the viscosity stability is lowered, and the continuous productivity is lowered. is there.
JP 2005-343112 A Japanese Patent No. 5-1174125

  The subject of the present invention is a viscosity that allows the epoxy resin composition for pultrusion molding to be sufficiently impregnated in pultrusion molding, and has excellent quick-curing properties while having small changes in viscosity during pultrusion molding, as well as mechanical properties and adhesiveness. It is to provide a resin composition for a molded article and a pultruded molded article excellent in the above.

  As a result of various studies to solve the above problems, the present inventor has found a resin composition for a pultruded product shown below.

Specifically, (1) (a) an epoxy resin, (b) an acid anhydride, (c) an imidazole derivative, and (d) a pultrusion-type epoxy resin composition containing a release agent that is liquid at 25 ° C. a) An epoxy resin is an epoxy resin containing 60 to 100 parts by weight of a bifunctional epoxy resin having a viscosity at 25 ° C. of 3000 mPa · s or less in 100 parts by weight of all epoxy resins, and (c) an imidazole derivative is 1-benzyl 2-methylimidazole, containing 0.1 to 5 parts by weight in 100 parts by weight of the total epoxy resin, and the bifunctional epoxy resin is composed of bisphenol F type epoxy resin, diglycidylaniline, diglycidyl o-toluidine An epoxy resin composition for a pultruded product, which is at least one selected from the above .

( 2 ) A pultruded product comprising a matrix resin obtained by curing the resin composition according to (1 ) and a reinforcing fiber.

( 3 ) The pultruded product according to ( 2 ), wherein the reinforcing fiber is a carbon fiber.

( 4 ) A building structure in which the pultruded product according to ( 2) or (3 ) is attached and reinforced.

  The epoxy resin composition for pultrusion molding of the present invention has a viscosity that can be sufficiently impregnated in the pultrusion molding method, has excellent quick curability, has a small viscosity change during pultrusion molding, and is excellent in mechanical properties and adhesiveness. To provide molded products.

The epoxy resin composition of the present invention is a pultrusion epoxy resin composition containing (a) an epoxy resin, (b) an acid anhydride, (c) an imidazole derivative, and (d) a mold release agent that is liquid at 25 ° C. (A) The epoxy resin is an epoxy resin containing 60 to 100 parts by weight of a bifunctional epoxy resin having a viscosity at 25 ° C. of 3000 mPa · s or less in 100 parts by weight of the total epoxy resin, and (c) an imidazole derivative is 1-benzyl-2-methylimidazole, containing 0.1 to 5 parts by weight in 100 parts by weight of the total epoxy resin, and the bifunctional epoxy resin is bisphenol F type epoxy resin, diglycidyl aniline, diglycidyl o- An epoxy resin composition for a pultruded product, which is at least one selected from the group consisting of toluidine .

  The (a) epoxy resin used in the present invention is an epoxy resin containing a bifunctional epoxy resin having a viscosity at 25 ° C. of 3000 mPa · s or less in an amount of 60 to 100 parts by weight in 100 parts by weight of all epoxy resins. The term “bifunctional” as used herein refers to a substance having two epoxy groups in the molecule. By including 60 parts by weight or more and 100 parts by weight or less of the bifunctional epoxy resin in 100 parts by weight of the total epoxy resin, a product having excellent mechanical properties is obtained when formed into a molded product.

  In addition, the bifunctional epoxy resin having a viscosity at 25 ° C. of 3000 mPa · s or less is preferably included in 100 parts by weight of the total epoxy resin from the viewpoint of improvement of mechanical properties, adhesion, and drawability by sufficiently reducing the resin viscosity. 70 to 100 parts by weight, more preferably 80 to 100 parts by weight, and most preferably 90 to 100 parts by weight is preferably used.

  A bifunctional epoxy resin having a viscosity at 25 ° C. of 3000 mPa · s or less preferably has a viscosity at 25 ° C. of 5 mPa · s or more and 3000 mPa · s or less. More preferably, they are 5 mPa * s or more and 2500 mPa * s or less. When it is 5 mPa · s or less, when it is finally combined with (b) acid anhydride or (c) imidazole derivative to form an epoxy resin composition, the initial viscosity is too low. As a result, the amount of adhesion of the surface may deteriorate and the surface quality and the like may deteriorate. When it is 3000 mPa · s or more, the final viscosity of the epoxy resin composition becomes high, so that the resin is not impregnated in the reinforcing fiber bundle at the time of pultrusion and may cause voids. .

The bifunctional epoxy resin viscosity is less than 3000 mPa · s at 25 ° C., bisphenol F type epoxy resin, diglycidyl aniline, should be at least one selected from the group consisting of diglycidyl o- toluidine. Such a bifunctional epoxy resin is required in terms of mechanical properties and adhesiveness when used as a reinforcing agent for buildings. Commercially available bifunctional epoxy resins having a viscosity at 25 ° C. of 3000 mPa · s or less include “jER (registered trademark)” 806 (viscosity: 2000 mPa · s) and “jER (registered trademark)”. “1750 (viscosity: 1300 mPa · s) (above, manufactured by Japan Epoxy Resin Co., Ltd.), GY285 (viscosity: 2500 mPa · s), PY306 (viscosity: 1400 mPa · s) (above, manufactured by Huntsman Advanced Materials) and the like.

  A commercially available product of diglycidyl aniline is GAN (viscosity: 120 mPa · s, manufactured by Nippon Kayaku Co., Ltd.).

  A commercially available product of diglycidyl o-toluidine is GOT (viscosity: 70 mPa · s, manufactured by Nippon Kayaku Co., Ltd.).

  Moreover, (a) As a viscosity at 25 degrees C of an epoxy resin, it is preferable that they are 5.0 mPa * s or more and 3000 mPa * s or less. More preferably, it is 5.0 mPa · s or more and 2500 mPa · s or less. If it is less than 5.0 mPa · s, the amount of adhesion to the reinforcing fiber may be reduced during pultrusion molding, which is not preferable because it may cause voids. If the viscosity is higher than 3000 mPa · s, the final Since the initial viscosity of the resin composition becomes too high, the impregnation property may deteriorate, which is not preferable. The viscosity mentioned here is determined by a measurement method using a cone-plate type rotational viscometer in ISO 2884-1 at 25 ° C. Moreover, initial viscosity refers to the viscosity immediately after mixing all the components with the ratio described in the preparation table.

  In addition, (a) epoxy resin can be blended with epoxy resin other than bifunctional epoxy resin having a viscosity at 25 ° C. of 3000 mPa · s or less in a range of 0 to 40 parts by weight in 100 parts by weight of all epoxy resins. . In this case, an epoxy resin other than a bifunctional epoxy resin having a viscosity at 25 ° C. of 3000 mPa · s or less needs to be blended within a viscosity range used for pultrusion molding. Specifically, the viscosity range used for pultrusion means that the viscosity is 200 to 1000 mPa · s when an epoxy resin composition for pultrusion products is used. It can be prepared in this area by addition / mixing. Examples of the epoxy resin other than the bifunctional epoxy resin having a viscosity at 25 ° C. of 3000 mPa · s or less include, for example, tetraglycidyldiaminodiphenylmethane, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, triglycidyl- Glycidylamine type epoxy such as p-aminophenol and triglycidyl-m-aminophenol, glycidyl ester phthalate, glycidyl ester type epoxy such as glycidyl hydrophthalate, bisphenol S type epoxy resin, bisphenol A type epoxy resin, etc. It is done. When more heat resistance is required, it is preferable to add a glycidylamine type epoxy resin.

  (B) is an acid anhydride. Although there is no restriction | limiting in particular as an acid anhydride, Since the viscosity of the resin composition obtained by mixing with (a) and (c) becomes low, what is a liquid at 25 degreeC is preferable, and especially the viscosity of 25 degreeC Is preferably 20 mPa · s or more and 1000 mPa · s or less. More preferably, it is 20 mPa · s or more and 200 mPa · s or less, and most preferably 20 mPa · s or more and 150 mPa · s or less. When a low-viscosity epoxy resin of 200 mPa · s or less is used when the viscosity is 20 mPa · s or less, the viscosity of the resin composition becomes too low, and the amount of the resin adhering to the reinforcing fibers may be reduced during pultrusion molding. is there. Specific examples include tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl nadic anhydride, trialkyltetrahydrophthalic anhydride, dodecyl succinic anhydride, and the like. In particular, hexahydrophthalic anhydride and methylhexahydrophthalic anhydride are preferred because of low viscosity of about 40 to 70 mPa · s and excellent heat resistance of the resulting cured product. Moreover, you may mix and use 2 or more types as needed.

  A commercially available product of methyltetrahydrophthalic anhydride is “Licacid (registered trademark)” MT500 (viscosity: 50 mPa · s) (manufactured by Shin Nippon Rika Co., Ltd.).

  Commercially available products of hexahydrophthalic anhydride include “Licacid (registered trademark)” HH (melting point: 34 ° C.) (manufactured by Shin Nippon Rika Co., Ltd.), HHPA (melting point: 35 ° C.) (Maruzen Petrochemical Co., Ltd.) can give.

  As commercial products of methylhexahydrophthalic anhydride, EPICLON “(registered trademark)” B-570 (viscosity: 40 mPa · s), EPICLON “(registered trademark)” B-650 (viscosity: 65 mPa · s) (larger than above) Nippon Ink Co., Ltd.).

  As a commercial product of a mixture of hexahydrophthalic anhydride and methylhexahydrophthalic acid, “Rikacid (registered trademark)” MH700 (viscosity: 60 mPa · s) (manufactured by Shin Nippon Rika Co., Ltd.).

  A commercially available product of methyl nadic anhydride is Kayahard “(registered trademark)” MCD (viscosity: 200 mPa · s) (manufactured by Nippon Kayaku Co., Ltd.). A commercially available product of trialkyltetrahydrophthalic anhydride is “jER Cure (registered trademark)” YH-306 (viscosity: 130 mPa · s) (manufactured by Japan Epoxy Resins Co., Ltd.).

  (B) Since the acid anhydride has a good balance between the initial viscosity of the epoxy resin composition and the obtained heat resistance, (a) the active hydrogen of the acid anhydride with respect to 1 equivalent of active hydrogen of the epoxy group contained in the epoxy resin It is preferable to determine the blending amount so that the equivalent (the molecular weight of the acid anhydride divided by the number of reaction points) is in the range of 0.5 to 1.5 equivalents. More preferably, it is 0.7-1.2 equivalent. When the amount is less than 0.5 equivalent, the initial viscosity may be increased and curing may be insufficient. When the amount is more than 1.5 equivalent, the mechanical properties of the cured product may be deteriorated.

(C) The imidazole derivative is 1-benzyl-2-methylimidazole . The reason why 1-benzyl-2-methylimidazole is an essential component is lower than that of an imidazole derivative having an active hydrogen at the 1-position because the substituent at the 1-position has a low activity as an anionic polymerization initiator. Although the viscosity stability of the epoxy resin composition is significantly improved, the gel time of the epoxy resin composition under molding conditions is not different from that of an imidazole derivative having no substituent at the 1-position .

  As a commercially available product of 1-benzyl-2-methylimidazole, “jER Cure (registered trademark)” BMI12 (viscosity: 2300 mPa · s, manufactured by Japan Epoxy Resins Co., Ltd.) can be mentioned.

( C) An imidazole derivative that does not have a substituent at the 1-position of the imidazole ring may be added to the imidazole derivative as long as the viscosity stability is not adversely affected. When specific commercial products of imidazole derivatives having no substituent at the 1-position of the imidazole ring are listed, “Cuazole (registered trademark)” 2MZ (manufactured by Shikoku Kasei Co., Ltd.) is a commercially available product of 2-methylimidazole. can give.

  Examples of 2-ethyl-4-methylimidazole include “Curazole (registered trademark)” 2E4MZ (manufactured by Shikoku Kasei Co., Ltd.) and “jER Cure (registered trademark)” EMI24 (manufactured by Japan Epoxy Resin Co., Ltd.).

(C) imidazole derivatives with respect to 100 parts by weight of total epoxy resin, Ru 0.1-5 parts by der. When the amount is less than 0.1 part by weight, slow curing rate of the resin composition, have such used in high-speed molding. Further, when it is more than 5 parts by weight, greater increase in the viscosity of the resin composition, that can not be stable production in continuous production. In particular, the amount is preferably 0.5 to 4 parts by weight.

The epoxy resin composition of the present invention includes a release agent liquid at 25 ℃ (d). Since the release agent is in a liquid state, even a low viscosity composition can be mixed uniformly. Moreover, pultrusion moldability improves by mixing a mold release agent in resin. This improves the orientation of the fibers in the molded product, so that the mechanical properties such as the compressive strength of the molded product and the adhesion to the adhesive due to the smooth surface increases the concrete reinforcement to the building. Adhesiveness when pasting as an agent is improved.

(D) It is preferable that the compounding quantity of a liquid mold release agent at 25 degreeC is 0.1-8 weight part with respect to 100 weight part of all the epoxies. More preferably, it is 0.1 to 6 parts by weight. If it is 0.1 parts by weight or less, sufficient releasability may not be obtained. Moreover, when 8 weight part or more is added, the intensity | strength of a molded product falls or adhesiveness with the adhesive agent at the time of affixing on a building may fall.

  Such a liquid mold release agent is not particularly limited as long as it does not phase separate from the epoxy resin composition and does not evaporate or decompose at the mold temperature. Especially, in order to suppress the influence on the viscosity of a resin composition, the thing of the viscosity of 50 mPa * s or more and 1000 mPa * s or less of a liquid mold release agent at 25 degreeC is used preferably.

  Specific examples of commercially available products include MOLDWIZ INT-1846 (viscosity: 425 mPa · s), MOLDWIZ INT-1836, MOLDWIZ INT-1850 (viscosity: 350 mPa · s), and MOLDWIZ INT-1854 obtained by polycondensation of an organic acid or glyced. Can be given. Further, as a silicone oil type, dimethyl silicone oil KF-96 (manufactured by Shin-Etsu Chemical Co., Ltd.) can be mentioned.

  In the epoxy resin composition of the present invention, (a) an epoxy resin, (b) an acid anhydride, and (c) an imidazole derivative are stirred with a stirring rod and mixed. Although heating and pressurization may be performed as necessary, long-time heating is not preferable because it increases the viscosity of the resin composition. The mixed epoxy resin composition needs to be dissolved uniformly. Even if some of them are solid or liquid, they form a separated phase, which is not preferable because it may cause local non-uniformity of components in the impregnation process. In addition, (d) a release agent that is liquid at 25 ° C. may be added at any stage of the mixing process, but in order to disperse it uniformly, (b) an acid anhydride and (c) an imidazole derivative are mixed. Before (a) it is preferable to mix with an epoxy resin, stir well and disperse.

The initial viscosity at 25 ° C. immediately after mixing of the epoxy resin composition of the present invention is preferably 50 to 2000 mPa · s, more preferably 100 to 1000 mPa · s, in order to sufficiently impregnate the reinforcing fibers. If it is less than 50 mPa · s, the amount of resin impregnated into the reinforcing fibers may be reduced. On the other hand, if the viscosity is higher than 2000 mPa · s, it may be difficult to penetrate into the reinforcing fiber, resulting in insufficient impregnation and voids. Furthermore, in order to maintain productivity in continuous molding, the viscosity at 25 ° C. after leaving the epoxy resin composition at 25 ° C. for 8 hours is preferably 1.0 to 3.0 times the initial viscosity. . More preferably, it is 1.0 to 2.5 times. Gel time, curing agents, particularly large effect of Blend of imidazole, if thickening magnification is large, it is possible to suppress the thickening by the scores reduce the amount.

In order to achieve high-speed molding, it is preferable that the gel time at 150 ° C. of the epoxy resin composition is within 120 seconds and the gel time at 190 ° C. is within 60 seconds. More preferable gel time is within 90 seconds at 150 ° C. and within 30 seconds at 190 ° C. Gel time, greatly affected by Blend of imidazole, if insufficient, it is possible to further reduce the amount to the Fuyasuko.

  In the present invention, the gel time of the epoxy resin composition is measured using a curast meter device, and the time when the torque exceeds 0.001 N · m after the start of measurement is defined as the gel time.

  The Tg of the cured product obtained by heating the epoxy resin composition at 150 ° C. for 15 minutes is the equivalent ratio of the curing agent to the active hydrogen equivalent of the epoxy resin, such as changing the type of epoxy resin such as blending a polyfunctional epoxy resin ( The heat resistance is increased by setting it to 1 and the heat resistance is lowered by shifting it up and down from 1), but it is preferably 80 to 150 ° C. More preferably, it is 90 to 140 ° C. When Tg is lower than 80 ° C., the heat resistance is insufficient, and when it exceeds 150 ° C., the crosslink density is too high and the resin may become brittle.

  In the present invention, the glass transition temperature of the cured epoxy resin is a value measured using a dynamic thermomechanical measurement (DMA) apparatus at a heating rate of 5 ° C./min. Further, the glass transition temperature is the intersection of the base line on the lower temperature side of the step change portion due to the glass transition of G ′ and the tangent drawn at the point where the gradient of the step change portion is maximum, that is, the extrapolated glass transition start temperature. Was the glass transition temperature.

  As the reinforcing fiber, glass fiber, aramid fiber, carbon fiber, boron fiber and the like are preferable, but it is preferable to use carbon fiber because it is particularly excellent in strength. The tensile modulus of carbon fiber is preferably 200 to 500 GPa for civil engineering / architecture applications. The tensile elastic modulus of carbon fiber refers to the strand elastic modulus measured according to JIS R 7601 (1986).

  Moreover, it is preferable that the cross-sectional shape of the single fiber of carbon fiber is substantially circular. Here, the fact that the cross-sectional shape of the single fiber is substantially a perfect circle means that the ratio R / r between the radius R of the circle circumscribing the cross-sectional shape of the single fiber and the radius r of the inscribed circle is 1.0 to 1.1, preferably in the range of 1.0 to 1.05. When the cross-sectional shape of the single fiber is a perfect circle, the strength of the single fiber breaks due to abrasion between the single yarns or bundles of the carbon fiber at the time of pultrusion, reduction in strength, fluff generation, yarn breakage, etc. Trouble is unlikely to occur. Moreover, when the cross-sectional shape of the single fiber is an ellipse, an egg, a bean, or a three-leaf, the mechanical properties of the resulting composite material may be deteriorated. Examples of the carbon fiber having a perfect circular cross section include “Torayca (registered trademark)” T700S and “Torayca” (registered trademark) “M30S”.

  Further, 0.01 to 5% by weight of a component having at least one functional group selected from an epoxy group, a hydroxyl group, an acrylate group, a methacrylate group, an amide group, a carboxyl group, and a carboxylic acid anhydride as a sizing agent is attached to the carbon fiber. The resulting product is excellent in scratching during production and adhesion to the epoxy resin. In particular, those containing a component having an epoxy group or a hydroxyl group are preferred as the sizing agent. This is because an interaction such as a chemical bond or a hydrogen bond occurs between the functional group on the surface of the carbon fiber and the functional group in the polymer network of the resin cured product, thereby enhancing the adhesion between the carbon fiber and the resin cured product. . The amount of the sizing agent attached to the carbon fiber was determined by weighing the carbon fiber (W1) and then leaving it in an electric furnace set at a temperature of 450 ° C. for 15 minutes in a nitrogen stream of 50 liters / minute. Thermally decompose. Then, the carbon fiber after being transferred to a container in a dry nitrogen stream at 20 liters / minute and cooled for 15 minutes is weighed (W2), and the sizing agent adhesion amount is determined by the following equation.

Sizing adhesion amount (%) = [W1-W2] / W1 × 100
As the carbon fiber used in the present invention, one having 1000 to 200,000 filaments is preferably used. If the number is less than 1,000, the number of carbon fiber bobbins required to obtain a predetermined width and thickness is increased, which makes the operation complicated, and if it is 200,000 or more, the resin is not contained in the carbon fiber bundle. It may become difficult to impregnate and cause voids.

  The method for producing the epoxy resin pultruded product of the present invention will be described.

  In the present invention, a general pultrusion molding method is performed using an epoxy resin, and a pultrusion molded product can be obtained by heat-curing in parallel with pultrusion molding or after pultrusion molding. As a general pultrusion method, the reinforcing fiber is continuously passed through an impregnation tank of an epoxy resin composition, and is cured while being continuously pultruded by a tension machine through a squeeze die and a heating mold. Further, it is completely cured in an after cure oven. The above only shows an example of the pultrusion method, and is not limited.

  The impregnation tank is preferably maintained at 10 to 40 ° C. More preferably, it is 20-30 degreeC. When the temperature of the impregnation tank is 40 ° 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. When the temperature is 100 ° C. or lower, poor curing in the mold may occur, and when the temperature is 250 ° C. or higher, the runaway 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 increase the heat resistance or complete the reaction of the epoxy group. After curing, after passing through the mold and before winding, an 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 1 hour, although it depends on the curing temperature. A cure shorter than 5 minutes may be too short to complete the reaction. If it is longer than 1 hour, for example, when it is used online, there is a concern that the productivity is too long.

The carbon fiber weight content (Wf) of the pultruded product of the present invention is preferably 65 to 90% in order to sufficiently draw out the characteristics of light weight, high strength and high elastic modulus. More preferably, it is 70 to 85%. When it is 65% or less, it is difficult to obtain the light weight, high strength, and high elastic modulus characteristics of the present invention, and when it is 90% or more, voids may be generated inside.
Here, the Wf of the pultruded product 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 material molded by pultrusion is lightweight, has excellent mechanical properties such as strength and elastic modulus, excellent heat resistance, and excellent adhesiveness. Can be used as a reinforcing material.

  In addition, the pultrusion molding material in the present invention is excellent in elastic modulus, strength, and heat resistance, and also has excellent surface smoothness, so that it has excellent adhesion to an adhesive, and therefore has good adhesion to a building material. Excellent. For this reason. It can be optimally used as a reinforcing agent for building materials, and a building structure reinforced with a pultruded product of the present invention has improved resistance to bending stress.

  EXAMPLES Next, although an Example demonstrates this invention, this invention is not limited to these Examples.

(Resin raw material)
[ Epoxy resin ]
"JER (registered trademark)" 1750 (bisphenol F type epoxy resin, viscosity: 1300 mPa · s, manufactured by Japan Epoxy Resins Co., Ltd.)
"JER (registered trademark)" 806 (bisphenol F type epoxy resin, viscosity: 2000 mPas, manufactured by Japan Epoxy Resins Co., Ltd.)
"JER (registered trademark)" 828 (bisphenol A type epoxy resin, viscosity: 13000 mPa.s, manufactured by Japan Epoxy Resins Co., Ltd.)
GAN (diglycidyl aniline, viscosity: 120 mPa · s, manufactured by Nippon Kayaku Co., Ltd.)
“TETRAD-X (registered trademark)” (tetraglycidyl-m-xylenediamine, viscosity: 2000 mPa · s, manufactured by Mitsubishi Gas Chemical Co., Inc.)
[ Acid anhydride ]
"Licacid (registered trademark)" MH700 (Methylhexahydrophthalic anhydride / hexahydrophthalic anhydride, 70/30 mixture, viscosity: 60 mPa · s, manufactured by Shin Nippon Rika Co., Ltd.)
[ Imidazole derivatives ]
< Imidazole having a substituent at the 1-position >
“JER Cure (registered trademark)” BMI12 (1-benzyl-2-methylimidazole, viscosity: 2300 mPa · s, manufactured by Japan Epoxy Resins Co., Ltd.)
< Imidazole with no substituent at the 1-position >
"JER Cure (registered trademark)" EMI24 (2-ethyl-4-methylimidazole, solid, manufactured by Japan Epoxy Resins Co., Ltd.)
[ Release agent ]
<Mold release agent at 25 ° C>
・ "MoldWiz INT1846 (registered trademark)" (viscosity: 425 mPas, manufactured by AXEL PLASTICS RESEARCH LABORATORIES IMC.)
<Releasing agent that is not liquid at 25 ° C.>
・ Carnauba wax No. 1 (solid, manufactured by Nippon Wax Co., Ltd.)
(Reinforced fiber)
"Torayca (registered trademark)" T700S-24K (carbon fiber, perfect circular cross section, 24,000 filaments, manufactured by Toray Industries, Inc.)
"Torayca (registered trademark)" T300B-3K (carbon fiber , empty bean-shaped cross section, 3000 filaments, manufactured by Toray Industries, Inc.).

(1) Preparation of resin composition According to the blending ratio shown in the table, an epoxy resin, an acid anhydride, an imidazole derivative, and a release agent were mixed at 25 ° C. to obtain a resin composition.

(2) Viscosity measurement of resin composition According to the measurement method using a cone-plate type rotational viscometer in ISO 2884-1, immediately after adjusting the epoxy resin composition and in an isothermal apparatus at 25 ° C., it is allowed to stand for 8 hours. The measured viscosities were each measured at 25 ° 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) Gel time measurement of resin composition The gel time immediately after adjusting an epoxy resin composition was measured at 150 degreeC and 190 degreeC. The apparatus used was a curast meter V type manufactured by Nichigo Corporation. The sample amount was 2 cm ³ . The time when the torque reached 0.001 N · m after the start of measurement was defined as the gel time.

(4) Measurement of glass transition temperature of cured resin After adjusting the epoxy resin composition, the cured resin cured by heating at 150 ° C. for 15 minutes was used at a frequency of 1 Hz and a temperature of 25 using a tester ARES manufactured by Rheometric Scientific. It measured by heating up at -200 degreeC and 5 degree-C / min. The glass transition temperature is the intersection of the base line on the lower temperature side of the step change portion due to the glass transition of G ′ and the tangent drawn at the point where the gradient of the step change portion is maximum, that is, the extrapolated glass transition start temperature The transition temperature was used.

(5) Creation of a pultruded product The resin compositions of Examples 1 to 6 and Comparative Examples 1 to 5 were retained in a raw material tank at 25 ° C. for 2 hours. The carbon fiber is passed through the raw material tank containing the resin composition, impregnated with the resin, then inserted into a mold material, heated and cured at 170 ° C. for 2 minutes, and aftercured at 150 ° C. for 15 minutes, A fiber reinforced composite material having a thickness of 2 mm was obtained.

(6) Surface quality of pultruded product The surface of the carbon fiber reinforced composite material prepared by the method of (5) above was observed, and the fiber reinforced fiber cross section was observed with SEM. , If there are voids with a diameter of 2 μm or more without resin, or if the surface has unevenness of 4 μm or more on the surface by observation with a surface roughness meter, × indicates that there are no voids or unevenness. It was judged.

  The equipment and conditions used here are shown below.

(6) -1 Cross-section observation ・ Device: S-4100 scanning electron microscope (manufactured by Hitachi, Ltd.)
・ Acceleration voltage: 3kV
・ Vapor deposition: Pt-Pd about 4μm
・ Magnification: 20,000 times or more
(6) -2 Surface roughness measurement ・ Device: Surfcorder SE3400 (manufactured by Kosaka Laboratory)
・ Measurement speed 2mm / s
・ Measurement distance 10mm
(7) Interlaminar shear strength measurement of pultruded product The carbon fiber reinforced composite material prepared by the method of (5) was cut into a width of 10 mm and a length of 15 mm to obtain a test piece. This test piece was measured for interlaminar shear strength according to the method described in JIS K7078 (1991).

(8) 0 ° compressive strength of pultruded product The carbon fiber reinforced composite material prepared by the method of (5) was cut into a length of 100 mm and a width of 15 mm with the fiber direction as the length direction to obtain a test piece. Using this test piece, three-point bending was performed according to JIS K7074 (1988).

(9) 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.

(10) Alkali resistance test A sample of a carbon fiber reinforced composite material was immersed in an aqueous sodium hydroxide solution (pH = 14) according to JSE-E 549-2000. Changes in surface quality and changes in weight were evaluated. The change in the surface quality was evaluated as x when a change in the surface condition such as whitening was observed, and ◯ when there was no change. The weight increase / decrease was calculated from the difference in weight before and after immersion.

(11) Adhesive evaluation test Adhesiveness was evaluated according to JIS A6909 using a pultruded product produced according to (5) above and “Sikadur30 (registered trademark)” as an adhesive.

According to the comparison between Examples 1 to 6 and Comparative Examples 1 to 5 and the comparison between Example 4 and Reference Example 1, the epoxy resin composition for a pultruded product of the present invention has excellent viscosity stability, mechanical properties and resistance to resistance. It can be seen that an epoxy resin composition for pultrusion molding having excellent alkalinity and adhesive properties is obtained.

From the comparison between Examples 1 and 6 and Comparative Example 1 and Example 2 and Comparative Example 2, the initial viscosity is a viscosity that can be used for pultrusion molding due to the difference in imidazole derivatives, but the viscosity after 8 hours is large. It can be seen that imidazole having a substituent at the 1-position is superior in terms of stability. Further, the fiber reinforced composite materials of Examples 1 and 2 that are less affected by the progress of a partial curing reaction caused by being retained in the raw material tank for 2 hours and the minute gelation in the impregnation tank are It can be seen that the surface quality is improved, the Wf is increased, the interlaminar shear strength and the 0 ° bending strength are also increased as compared with 2. Moreover, it turns out that alkali resistance is also improving.

By comparing Examples 1 and 4 with Comparative Examples 3 and 6 from bisphenol F type epoxy resin having a viscosity at 25 ° C. of 3000 mPa · s or less to 13000 mPa · s bisphenol A type epoxy resin, the viscosity is stable. Although the properties do not change, it can be seen that the moldability and the molding quality are deteriorated by increasing the initial viscosity. Further, the alkali resistance is also lowered, and the surface quality is lowered and the weight is increased.

  A comparison between Example 5 and Comparative Example 4 shows that the absence of an acid anhydride has deteriorated moldability and the composite has a low Wf due to its high viscosity.

Furthermore, according to the comparison between Reference Example 1 and Comparative Example 5, by replacing 50 parts by weight of the bifunctional epoxy resin “jER (registered trademark)” 806 with the tetrafunctional epoxy resin TETRAD-X, It can be seen that the viscosity stability is lowered, and the surface quality and alkali resistance of the molded product are lowered.

  The epoxy resin composition for pultrusion molding of the present invention has a viscosity that can be sufficiently impregnated in the pultrusion molding method, has excellent fast curability and a long pot life, and can provide a molded product with excellent heat resistance. .

Claims (4)

(A) an epoxy resin, (b) an acid anhydride, (c) an imidazole derivative, and (d) an epoxy resin composition for pultrusion molding containing a release agent that is liquid at 25 ° C., wherein (a) the epoxy resin is , An epoxy resin containing 60 to 100 parts by weight of a bifunctional epoxy resin having a viscosity at 25 ° C. of 3000 mPa · s or less in 100 parts by weight of the total epoxy resin, and (c) an imidazole derivative is 1-benzyl-2-methylimidazole And at least 1 selected from the group consisting of bisphenol F type epoxy resin, diglycidyl aniline, and diglycidyl o-toluidine, containing 0.1 to 5 parts by weight in 100 parts by weight of the total epoxy resin. An epoxy resin composition for a pultruded product characterized by being a seed . A pultruded product comprising a matrix resin obtained by curing the resin composition according to claim 1 and reinforcing fibers. The pultruded product according to claim 2 , wherein the reinforcing fibers are carbon fibers. A building structure in which the pultruded product according to claim 2 is attached and reinforced.