JPS60199023A - Epoxy resin composition for carbon fiber reinforcement - Google Patents

Abstract

PURPOSE:To provide the titled composition composed of phloroglucinol triglycidyl ehter, its condensation product, and a curing agent, and suitable for a prepreg resin of a carbon fiber-reinforced composite material having excellent mechanical characteristics, heat resistance and water resistance. CONSTITUTION:The objective resin composition for prepreg is produced by adding a curing agent such as 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, dicyandiamide, boron trifluoride complex, etc. to phloroglucinol triglycidyl ether and/or its condensation product, and if necessary, compounding the mixture with <=50wt% cure accelerator and an additive such as epoxy resin, thermoplastic resin, elastomer, etc. The obtained resin composition is impregnated as a prepreg into a reinforcing fiber comprising a carbon fiber prepared from polyacrylonitrile, pitch, rayon, etc. and, if necessary, blended with glass fiber. The amount of the prepreg is preferably 20-45wt%.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to an epoxy resin for producing a carbon fiber reinforced composite material l11 (hereinafter abbreviated as CFRP) having excellent physical properties and good heat resistance and water resistance. Regarding the composition. More specifically, it is an epoxy resin suitable as a prepreg resin for producing CFRP, which has high performance mechanical properties necessary as a structural material, especially high interlaminar shear strength and compressive strength, and has excellent heat resistance and water resistance. The present invention relates to a resin composition.

[Prior art]

CFRP is widely used as premium sporting goods due to its excellent specific strength and specific modulus, but in recent years it has also begun to be used as a structural material for aerospace equipment, automatic 11s, etc. Therefore, the performance improvement of CFRP is 1
! In particular, improving compression sclerosis and interlaminar shear strength in a water-absorbed state are important issues.

In other words, CFRP, which is used as an II structural material for circular aircraft, etc., requires heat resistance in addition to mechanical properties. (Commercially available products include Sumitomo Chemical 11! ELM434 manufactured by Co., Ltd.)
or triglycidylaminophenol (hereinafter abbreviated as TGAP) represented by the general formula (1).
Aromatic amine type epoxy resins such as ELM120 manufactured by Gyogyo Co., Ltd.) are mainly used.

Among current epoxy resins, U TGAP has high heat resistance and excellent mechanical properties, and has higher compressive strength and 1-shear strength than TGDDM, but because of its high water absorption, its strength when absorbed is low. In particular, there was a problem in that the strength at high temperatures during absorption of M was low. On the other hand, although TGDDM is superior to TGAP in heat resistance and water resistance, it is inferior in mechanical properties such as compressive strength and interlaminar shear strength, and is therefore inferior in strength at high temperatures when absorbing moisture. Therefore, improving mechanical properties under high-temperature moisture absorption has become the biggest challenge in improving the physical properties of CFRP.

(Objective of the Present Invention) The present inventors have conducted extensive research aimed at obtaining a CFRP with excellent mechanical properties and good heat resistance and water resistance, and as a result, have arrived at the present invention.

[Configuration of the present invention]

That is, the present invention relates to an epoxy resin composition for reinforcing carbon mm, which is characterized by containing 1.3.5-phloroglycine triglycidyl ether or/and its condensation product and a curing agent.

Like TGPA, PGTGE has a high crosslinking density of the cured product,
Moreover, since three epoxy groups are directly attached to the benzene ring, the cured product has a high To value and a high elastic modulus. Furthermore, G1-GE is TGPA or TG
Unlike DDM, it does not contain highly hydrophilic nitrogen atoms, so it has the characteristic that the cured product has low water absorption.

Moreover, unlike amine-type epoxy, PGTGE has epoxy groups that are not close to each other, so it has fewer structural defects such as steric hindrance, and therefore a cured product with excellent flexibility can be obtained. Therefore, CFRP having PGTGE as a matrix has excellent mechanical properties, heat resistance, and water resistance.

Next, in implementing the present invention, the current epoxy A411
Similarly, it is necessary to add a curing agent. Examples of curing agents for epoxy resins include 4.4'-diaminodiphenylsulfone, 3.3' diaminodiphenylsulfone, dicyandiamide, boron trifluoride complexes, and polyphenol compounds, which are commonly used as curing agents for epoxy resins. Either can be used. However, in order to most effectively achieve the objects of the present invention, aromatic diamines such as 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, or mixtures thereof, or dicyandiamide are preferred.

In particular, when diaminodiphenylsulfone is used, CFRP with the best heat resistance can be obtained.

In addition to these curing agents, if necessary, a curing accelerator may be used in combination to reduce the curing moisture content.

In carrying out the present invention, other additives such as epoxy resins, thermoplastic resins, and elastomers may be added as long as the effects of the present invention are not affected. In particular, bisphenol A diglycidyl ether such as Ep-828 and Eplool manufactured by Yuka Shell Epoxy Co., Ltd. and phenol novolak type epoxy resins such as Ep-152 and Eρ-154 manufactured by Yuka Shell Epoxy Co., Ltd. may be added. However, from the viewpoint of heat resistance, it is preferable that PGTGE be contained in an amount of at least 50% by weight in the total amount of the epoxy resin excluding the curing agent.

Furthermore, when using the resin II # compound acid repreg resin composition according to the present invention, the resin is prepolymerized with a small amount of aromatic diamine before adding a curing agent for the purpose of adjusting the viscosity as necessary. It's okay to do that.

In addition, in carrying out the present invention, other fibers such as glass fibers and organic fibers may be mixed in addition to carbon fibers as the reinforcing fibers, and the reinforcing fibers may be in the form of unidirectional prepregs or cross-linked fibers. Prepreg is also acceptable. Furthermore, the carbon fiber used is polyacrylonitrile-based,
Any carbon fiber yarn, such as pitch yarn or rayon yarn, may be used. Furthermore, the proportion of the resin in the prepreg 'IF+ is usually in the range of 2011% to 45% by weight, more preferably in the range of 25 to 38% by weight.

c) Effects of the present invention) According to the present invention, a carbon fiber reinforced composite material having excellent mechanical properties and good heat resistance and water resistance can be obtained.

Hereinafter, the content of the present invention will be explained in more detail with reference to Examples.

Example 1 5 with stirring device, thermometer, dropping funnel, and separating funnel
Add 1,3,5-trihydroxybenzene () [cologlucin] dihydrate 243Q (1,
5 mol) and 1772 ml of 1-bichlorohydrin (22,5 mol)
mol>, heated and stirred at 50°C in an A-il bath,
Furo[]glucine was completely dissolved. After F[I D glucine was completely dissolved, the water in the reaction system was completely removed under reduced pressure, and after tJ, 14.80 (0.09 mol) of benzyltrimethylammonylamide was added and the mixture was heated at 50°C. The mixture was stirred for 24 hours.Then, purified water was used to separate and remove benzyltrimethylammonium chloride in the aspect ratio system, and the reaction system was then heated to reduce the evaporation to completely remove water in the system.Next, sodium hydroxide was added to the reaction system. 36% solution 500a of
The mixture was added dropwise while maintaining the reaction system at 80°C, 100rm, and 1100r. After the addition was completed, stirring was continued for an additional 310 minutes, and then excess 1-bichlorohydrin was removed. Next, 1Q of methyl isobutyl ketone and 1Q of water were added, the resulting salt was separated, and the resulting salt was washed with - amount of water, the first layer was separated, and the solvent was removed. Obtained ether. The epoxy equivalent weight measured by the hydrochloric acid-dioxane method was 135.

Example 2 4.4 per 100O of epoxy resin obtained in Example 1
A unidirectional prepreg was created by a hot melt method using a 11-fat composition containing 45.9 g of 1-diaminodiphenylsulfone and using Torayka'T400 manufactured by Toshi Co., Ltd. as a reinforcing fiber. . The resin content in the obtained prepreg was 34.21%, and the carbon all content was 145 g/'m'.

The obtained prepreg was cut into a size of 3σcm x 30C and laminated so that the fiber directions were in the same direction. The number of laminated prepreg sheets is 6 for tension and compression and 12 for others, both of which are autoclay 7 medium r and ff force 6.
kv/a+f, mtul A cured plate was prepared by curing at 80°C for 2 hours.

The volume content of carbon III in the hardened plate was 61.0%, and D
■9 measured by SC was 230°C.

A test piece was cut out from the obtained hardener, and ASTM, [')
-638, I') -790, D-2344, D-341
The physical properties of the composite were measured according to Example 0. The results obtained are summarized in Table 1. In the water absorption test, the test piece was immersed in warm water at 73°C for 14 days and then subjected to measurement.

Comparative Example 1 “Sumi Epoxy” manufactured by Sumitomo Chemical T-Gyo Co., Ltd. [1M120
A cured board was prepared in the same manner as in Example 2, except that a tree composition containing 430 parts of 4,4'-diaminodiphenylsulfone was mixed with 1000 parts of 4,4'-diaminodiphenylsulfone. The volume content of carbon fiber in the obtained cured plate was 6182%, and DSC
T9 measured at 212°C.

Next, the physical properties of the composite were measured in the same manner as in Example 2, and as shown in Table 2, the heat resistance, especially the heat resistance upon water absorption, was significantly inferior to that of Example 2.

Comparative Example 2 “Sumi Epoxy” E 1-M- manufactured by Sumitomo Chemical Co., Ltd.
A cured plate was prepared in the same manner as in Example 2, except that a resin composition containing 1 ooo of 434 and 42 CJ of 4,4'-diaminodiphenylsulfone was used.

The volume content of carbon lIH in the obtained cured plate was 60.7
%, and the Tg measured by DSC was 232°C.

Next, the physical properties of the composite measured in the same manner as in Example 2 are summarized in Table 3. Since the physical properties at room temperature were inferior to those of Example 2 and Comparative Example 1, the physical properties at high temperature water absorption were also inferior.

Claims (1)

[Claims] (1) An epoxy resin composition for reinforcing carbon fibers, comprising phloroglycin triglycidyl ether or/and its condensation product and a curing agent.