JPH03115331A - Epoxy resin composition for prepreg - Google Patents

Abstract

PURPOSE:To obtain the title composition which is curable at a low temperature and can be integrally molded with a lowly heat-resistant foam such as a urethane or acryl foam by using an epoxy resin and a mixture of three specified reaction products as the components. CONSTITUTION:The purpose composition consists of an epoxy resin (e.g. bisphenol A-derived epoxy resin) and a mixture comprising a first reaction product between a glycidyl ether (desirably phenyl glycidyl ether) and an imidazole (desirably 2-methylimidazole), a second reaction product among an imidazole having a substituent in the 1-position [desirably 1-(2-hydroxy-3- butoxypropyl)-2-methylimidazole], a compound having phenolic active hydrogen atoms (desirably bisphenol A) and an epoxy resin, and a third reaction product between a compound having active hydrogen atoms and a tert-amino in the molecule [desirably 2,4,6-tris(dimethylaminomethyl)phenol] and an epoxy resin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an epoxy resin composition for prepregs, and particularly provides an epoxy resin composition for prepregs that can be cured at low temperatures.

[Issue 8 to be solved by the prior art and the invention] Conventionally, epoxy resins used for prepregs are heated at relatively high temperatures (
For example, many products cure at temperatures between 120 and 180 degrees Celsius (120 to 180 degrees Celsius), and for this reason, when prepregs are bonded together using a foam material such as urethane or acrylic as a core material and are integrally molded, the curing temperature is too high, making it difficult to perform integral molding. There was a problem.

Furthermore, in applications such as tooling prepreg, conventional epoxy resins for prepregs cannot be used because of their high curing temperatures. Furthermore, in order to manufacture a composite material using polyethylene fibers or the like as a reinforcing material, there is a problem in that the curing temperature of conventional epoxy resins for prepregs is high.

Therefore, it has been desired to develop an epoxy resin for prepregs that cures at low temperatures and has excellent storage stability.

The present inventors have completed the present invention as a result of intensive research aimed at providing an epoxy resin composition that cures at a lower temperature and has superior storage stability compared to conventional epoxy resins for prepregs. Ta.

[Means for Solving the Problems] That is, the present invention provides: [A] an epoxy resin; [B] (1) a reaction product of glycidyl ethers and imidazoles; (2) an imidazole having a substituent at the 1-position. and (3) a mixture consisting of a reaction product of a compound having active hydrogen and a tertiary amino group in the molecule and an epoxy resin. Epoxy resin composition for prepreg.

As the epoxy resin used as component [A] in the present invention, any known epoxy resin can be used. For example, liquid or solid bisphenol A epoxy resin, brominated bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, cresol novolak epoxy resin, glycidylamine epoxy resin, alicyclic epoxy resin. Examples include resins, glycidyl ester type epoxy resins, heterocyclic epoxy resins, and other commercially available epoxy resins. Also, phenyl glycidyl ether,
Allyl glycidyl ether, which is used as a reactive diluent for epoxy resins, may be used in combination.

[The reaction product of glycidyl ethers and imidazoles used in component (1) of component B (hereinafter referred to as component [B]-(1)) is such that the amount of imidazole is 0.5 to 1 mole of glycidyl ether. 1.5 mol, preferably 0.8~
It is obtained by reacting at a ratio of 162 moles.

The reaction can be carried out in the presence or absence of a solvent, and optionally a catalyst may be used. As the solvent, aromatic solvents such as benzene, toluene, and xylene, polar solvents such as methyl ethyl ketone, methyl isobutyl ketone, dimethyl formamide, and dimethyl sulfoxide, etc. can be used. The reaction temperature is usually 50 to 150'C, preferably 70 to 120C, and the reaction time is arbitrarily determined, but is usually 1 to 20 hours.

Examples of glycidyl ethers include allyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and phenyl glycidyl ether is preferred.

Examples of imidazoles include imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-sebutadecanylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, l-benzyl-2-
Examples include methylimidazole, but 2-methylimidazole is preferred.

The reaction product of an imidazole having a substituent at the 1-position, a compound having a phenolic active hydrogen, and an epoxy resin used for the [B] acid component (2) (hereinafter referred to as the [B]-(2) component) is: It is obtained by reacting the three in the presence or absence of a solvent at a temperature of 15 to 150'C1, preferably 20 to 100C.

The reaction time is arbitrarily determined, but is usually 10 minutes to 5 hours. When the reaction is carried out in the presence of a solvent, the above [B]-(+
) can be used. The reaction ratio is 0.05 to 1.5 mol, preferably 0.1 mol of imidazoles having a substituent at the 1-position, per 1 mol of epoxy resin.
-1.0 mol, and 0.05 to 1 mol, preferably 0.1 to 0.5 mol of the compound having phenolic active hydrogen.

Examples of compounds having a substituent at the 1-position include 1-(2
-Hydroxy-3-phenoxyprobyl)2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-ethyl-4-methylimidazole, 1-
(2-hydroxy-3-butoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-butoxypropyl)-2-ethyl-4-methylimidazole, and in particular 1-(2-hydroxypropyl)-2-methylimidazole can be mentioned. 3-Butoxypropyl)-2-methylimidazole is preferred.

Examples of the compound having phenolic active hydrogen include bisphenol A1 bisphenol F1 bisphenol 81 catechol, resorcinol, hydroquinone, pyrogallol, and phenol novolac resin, with bisphenol A being particularly preferred.

As the epoxy resin, the same epoxy resin as used in component [A] can be used, but bisphenol A type epoxy resin is preferred.

The reaction product of the compound having active hydrogen and a tertiary amino group in the molecule used in component (3) of [B] (hereinafter referred to as component [B]-(3)) and the epoxy resin is a mixture of the epoxy resin and the epoxy resin. in the presence or absence of , at a temperature of 15 to 1.50°C
, preferably by reacting at 20 to 100°C. The reaction time is usually IO minutes to 5 hours. When the reaction is carried out in the presence of a solvent, the same solvent as in the case of component [B]-(1) can be used. The reaction ratio is 0.2 to 1.5 moles, preferably 0.5 to 1 mole of the compound having active hydrogen and a tertiary amino group in the molecule per mole of the epoxy resin.

Examples of compounds having active hydrogen and a tertiary amino group in the molecule include 2-dimethylaminoethanol, 2.4.
6-) Lis(dimethylaminomethyl)phenol, 2
-(dimethylaminomethyl)phenol, 1-(2-hydroxy-3-phenoxyprobyl)-2-methylimidazole, l-(2-hydroxy-3-phenoxypropyl)-2-ethyl-4-methylimidazole, 1-(
2-hydroxy-3-phenoxyprobyl)-2-phenylimidacillin, 2-diethylaminoethanol,
■-Methyl-2-dimethylaminoethanol, ■(
Examples include 2-hydroxy-3-butoxypropyl)2-methylimidazole, but in particular 2,4.6
- Tris(dimethylaminomethyl)phenol is preferred.

As the epoxy resin, the same epoxy resin as used in component [A] can be used, but bisphenol A type epoxy resin is preferred.

In the epoxy resin composition for prepreg of the present invention, the blending ratio of component [A] and component [B] is component [A] 1o
o parts by weight, component [B] is 5 to 40 parts by weight, preferably 10 to 30 parts by weight. In addition, CB in component [B]-(1), [B-co(2) and [B]-(3
) The mixing ratio of each component is 10 to 150 parts by weight, preferably 20 to 100 parts by weight of component [B]-(2) to 100 parts by weight of component [B]-(1), and Component (3) is used in an amount of 1 to 150 parts by weight, preferably 2 to 100 parts by weight.

The epoxy resin composition for prepreg of the present invention usually has a
It cures at a low temperature of 1.00°C and has excellent storage stability, and can be suitably used as a matrix resin for prepregs using glass fibers, carbon fibers, aramid fibers, polyethylene fibers, etc. as reinforcing fibers.

In addition, other resins and additives can be blended into the epoxy resin composition for prepreg of the present invention as long as they do not impair the purpose of the present invention.

[Effects of the Invention] The epoxy resin composition for prepregs of the present invention can be cured at a low temperature that could not be achieved with conventional epoxy resins for prepregs, so it can be integrally molded with foam materials such as urethane and acrylic that have low heat resistance. Furthermore, since it has a high glass transition temperature when post-cured, it can also be used as a tooling prepreg.

[Examples] The present invention will be specifically described below with reference to Examples, but the present invention is not limited thereto.

[B] Preparation of acid component 15.24 g of phenyl glycidyl ether and 8.22 g of 2-methylimidazole were reacted at 80°C for 3 hours [B
]-(1) component.

1-(2-hydroxy-3-butoxypropyl)2-methylimidazole io, 6g, bisphenol A 5
．． 7g and 19g of bisphenol A epoxy resin (Epicoat 828, manufactured by Yuka Shell Epoxy Oki) at 80%
The mixture was reacted at ℃ for 2 hours to obtain component [B]-(2).

2.4.8-) 26.5 g of lis(dimethylaminomethyl)phenol and 33.4 g of Epicote 828 in 1
The mixture was reacted at 00°C for 1 hour to obtain the CB]-(3) component.

Example 1 82 g of Epicoat (bisphenol A epoxy resin,
Yuka shell epoxy stock system) 45 heavy whole, Epicoat 1
001 (bisphenol A type epoxy resin, manufactured by Yuka Shell Epoxy Co., Ltd.) 55 parts by weight, the above [B]-(1),
Carbon fibers were impregnated with an epoxy resin composition consisting of 20 parts by weight of component [B], in which [B]-(2) and [B]-(3) were blended in a weight ratio of 1:1:0.2, respectively. and prepared prepreg. The carbon fiber used had a tensile strength of 35 ONg/#2 and a tensile modulus of 23 t/s2.

80 tons of prepregs obtained in this way were laminated,
A unidirectional flat plate of carbon fiber reinforced plastic (CFRP) having a thickness of 2# was obtained by curing at 1hr. The volume content of carbon fiber in this CFRP is 50% by volume, the tensile strength is 180Kg/mrrt, and the tensile modulus is 12t/mrrt.
It was #2.

Further, this prepreg was bonded to acrylic foam and urethane foam and cured at 80°C for 1 hour, but no deformation was observed in the finished product.

Furthermore, even after leaving this prepreg at room temperature for 50 days,
There were no changes in gel time, resin flow tack, or drapeability.

Comparative Example 1 100 parts by weight of Epicote 828, 4 parts by weight of dicyandiamide, and 5 parts by weight of dichlorophenyldimethylurea were mixed to obtain an epoxy resin composition. When this resin composition was subjected to a curing test, it was not cured at 80°C for 1 hour, but was cured at 130°C for 1 hour.

This resin composition was impregnated into the same carbon fiber as in Example 1 to obtain a unidirectional bobble leg. When this prepreg was bonded to acrylic foam and cured at 130°C for 1 hour, the finished product was significantly deformed.

Example 2 Epicote 828 30 parts by weight, Epicote 100
4 (bisphenol A type epoxy resin, oil-based shell epoxy stock) 40 parts by weight, YH434 (glycidylamine type epoxy resin, manufactured by Tobu Kasei ■) 30 parts by weight, before self [B Co (1), [B Co ( 2) and [B]-(3)
The carbon fiber used in Example 1 was impregnated with an epoxy resin composition consisting of 30 parts by weight of component [B] blended in a weight ratio of I: l: 0.1 to prepare a prepreg.

The prepregs obtained in this way are laminated in one direction.
Cured at 0°C for 1 hour. The volume content of carbon fiber in this CFRP is 60% by volume, and the tensile strength is 18ONg/
The tensile modulus was 12t/m2.

Further, this prepreg was left at room temperature for 40 days, but there was no change in gel time.

Furthermore, after curing this prepreg at 80°C for 1 hour in IH1,
After curing at 200℃ for 2 hours, the glass transition temperature was 1.
The temperature reached 80℃.

Example 3 Epicoat 828 40 parts by weight, Epicoat 154
(phenol novolak type epoxy resin, manufactured by Yuka Shell Epoxy Co., Ltd.) 20 parts by weight, Evototo YDCN701 (
Cresol novolac type epoxy resin, manufactured by Tobu Kasei)
40 parts by weight, the weight ratio of [B]-(1), [B-co (2) and [B]-(3) is 1:0.5:
A prepreg was prepared by impregnating polyethylene fibers with an epoxy resin composition consisting of 25 parts by weight of component [B] mixed at a ratio of 0.5. The tensile strength of the polyethylene fiber used was 35.0 to 9/mit+'', and the tensile modulus was lot
/ It was familiar 2.

The prepregs obtained in this way are laminated in one direction.
It was cured at 0°C for 1 hour. The volume content of polyethylene fibers in this polyethylene fiber reinforced plastic was 60% by volume, the tensile strength was 170 kg/shoe2, and the tensile modulus was 5.5 t/mm2.

Furthermore, even after this prepreg was left at room temperature for 45 days, there were no changes in gel time, resin flow tack, or drape properties.

Example 4 70 parts by weight of Epicote 828, Epicote 1.0
30 parts by weight of 04, Amicure PN23 (manufactured by Ajinomoto ■)
A prepreg was prepared by impregnating the carbon fibers used in Example 1 with an epoxy resin composition in which 20 parts by weight of the following were mixed.

The prepregs obtained in this way are laminated in one direction.
Cured at 0°C for 1 hour. The volume content of carbon fiber in this CFRP is 60% by volume, and the tensile strength is 1.85Kg.
/mm2, and the tensile modulus was 11.8t/mm2.

Furthermore, this prepreg was left at room temperature for 50 days, but there was no change in gel time, resin flow tack, or drapeability.

Claims (1)

[Scope of Claims] [A] An epoxy resin; [B] (1) a reaction product of a glycidyl ether and an imidazole; (2) a compound having an imidazole having a substituent at the 1-position and a phenolic active hydrogen; An epoxy resin composition for a prepreg, comprising: a reactant with an epoxy resin; and (3) a blend consisting of a reactant with an epoxy resin and a compound having active hydrogen and a tertiary amino group in the molecule.