JPS6143615A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:The titled composition, consisting of solid and liquid bisphenol A type epoxy resin having respectively specific epoxy equivalents and viscosities, dicyandiamide (derivative) and dialkylurea derivative, and having improved low- temperature curability, reinforcing and impregnation properties. CONSTITUTION:An epoxy resin composition obtained by incorporating a solid or semisolid bisphenol A type epoxy resin having about 400-5000 epoxy equivalent and about 60-105 deg.C softening point and liquid bisphenol A type epoxy resin having about 175-250 epoxy equivalent and about 8000-50000cP viscosity (25 deg.C) with a dicyandiamide (or a derivative thereof) as a curing agent, e.g. 1-(o-tolyl)biguanide, and a dialkylurea derivative expressed by the formula (R1 and R2 are lower alkyl; X1 and X2 are H, halogen, lower alkyl, lower alkoxy or nitro) as a curing accelerator, e.g. 3-phenyl-1,1-dimethylurea, and if necessary adding a flexibilizer, e.g. rubber, thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an epoxy resin composition. More specifically, the present invention relates to an epoxy resin composition comprising an epoxy resin, dicyandiamide or a derivative thereof, and a dialkylurea derivative.

[Conventional technology]

BACKGROUND OF THE INVENTION It is common practice to impregnate reinforcing materials such as glass fibers with thermosetting resins such as epoxy resins and unsaturated polyester resins, and to cure them to obtain various molded products. In addition, in this type of application, pre-impregnated materials such as plate-like materials in which the reinforcing material is impregnated with the resin that serves as the matrix (
A heat-cured molded product is also reinforced by stacking several to several tens of layers of prepreg.

Thermosetting resins used in such applications are required to have the following properties.

(1) Prepreg has good storage stability. Prepreg, as its name suggests, is a material impregnated with 1,000 mI, and if it hardens during storage, it will behave unstable when it is laminated and hardened. As a result, gelation occurs in the Gripreg state, and defective molded products are likely to occur.

(2) Prepreg has appropriate tackiness (adhesiveness) Prepreg is rarely used as a single layer, but rather as a laminate of multiple layers, so each layer is completely mutually bonded when laid up. mM means that the layers are in close contact and that no air is allowed to enter between the layers. Therefore, for K, it is necessary that the prepreg maintains appropriate tackiness, and the degree of tackiness is judged by finger touch at 25°C. It is preferable that there be.

(8) The prepreg has good drapability Drapability refers to the property of the prepreg layer to faithfully follow the surface shape of other objects such as molds (mold conformability), and it refers to the property of the prepreg layer to faithfully follow the surface shape of other objects such as molds. This is an important property in the case of

(4) The prepreg has excellent low-temperature curing properties, which is approximately 150 to 100% of the usual temperature used for curing of ebo beef fat.
It is important to cure at 100°C or less, which is significantly lower than 80°C. What is usually said to be low temperature curing is 1
It is said that sufficient strength and elastic modulus are exhibited within 15 hours under temperature and pressure conditions of 30° C. or lower and 10 Kff or lower.

Various epoxy resin compositions have been proposed as low-temperature curable prepregs. For example, compositions consisting of an epoxy resin, dicyandiamide or its derivatives, and dialkylurea are disclosed in Japanese Patent Application Laid-Open No. 16056/1986, 55 -71749, No. 55-73725, No. 57-49646, No. 58-23830, No. 58-167625, and No. 58-18
It is described in Publication No. 3723, etc.

However, although many epoxy resin compositions are known, there are none that simultaneously satisfy the above conditions when used in prepregs.
[Problems to be Solved by the Invention] Considering this fact, the present inventors have developed an epoxy resin composition that simultaneously satisfies each of the above conditions when used in prepregs. As a result of various studies in search of a solution, it was found that the problems of the invention can be effectively solved by using a solid or semi-solid and liquid bisphenol type epoxy resin in combination as the epoxy resin of the composition. I discovered that.

[Means for Solving the Problems] and [Operation] Accordingly, the present invention relates to an epoxy resin composition used for a Glypreg layer, etc. Here, R, and R2 are lower alkyl groups,
X and x2 are a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group or a nitro group.
In product c, epoxy equivalent 4 as epoxy resin.
00-1000, solid to semi-solid bisphenol ha epoxy resin with a softening point of 60-105°C and an epoxy equivalent of 175-250, a viscosity of 80oO-50,000
APA (25° C.) liquid bisphenol A/A type epoxy resins are both used.

Solid to semi-solid bisphenol AM epoxy resins generally have an epoxy equivalent of about 400 to 100
, preferably #450~rso, t1m and about 60 points
N105°C, preferably about 60-90°C is used. As such bisphenol A, W epoxy resin, a halogenated bisphenol type epoxy resin substituted with 2 to 4 ha-halogen atoms, preferably bromine atoms, per 41 ft of aroma, is used in an amount of about 2 to 2 halogenated bisphenol type epoxy resins, based on bromine in the composition.
It can also be used in a ratio of up to 0:1%, and in this case, the flame resistance of the composition can be improved. These epoxy resins can be used in the form of oligomers or grebolimers, and since they are in either a solid or semi-solid state, they function to prevent the epoxy resin from flowing down from the reinforcing material during prepreg production. .

The liquid bisphenol A type epoxy resin generally has an epoxy output of about 175 to 250, preferably about 175 to 200, and a viscosity of about 8000 to 500.

ops, preferably about 9000-25000 ape
(25°C) is used. Since these bisphenol A type epoxy resins are in a liquid state, they allow the resin to easily penetrate into the t-sleeve attachment material during impregnation, and also impart appropriate tack and drape properties to the prepreg. Since it forms a higher crosslinking density than a semi-solid one, it also plays the role of forming a resin with high heat resistance and hardness.

These bisphenol Affi epoxy resins are in solid to semi-solid form and liquid form, and the former is generally about 95%! i
Out of quantity, preferably about 70 to 9011j1%, the latter about 5%
It is used in a proportion of 0 to 5% by weight, preferably about 30 to 101%. When both bisphenol A type epoxy resins are used in such a ratio, the effects unique to the epoxy gutter composition of the present invention are exhibited.

As mentioned above, many epoxy resin compositions comprising epoxy resins, dicyandiamide or its derivatives, and dialkyl ureas are known, and in particular, many are known to be used in combination with phenol novolac type epoxy resins and bisphenol A type epoxy resins. However, none of them has been found to have the unique effects that can be achieved when a bimodal bisphenol A type epoxy resin is used in combination in the present invention.

Dicyandiamide or its derivatives used as curing agents, such as 1(o)'Jl)biguanide,
l,3-diphenylguanidine and the like do not increase the viscosity of the yarn after the composition according to the present invention is impregnated into the reinforcing material and the solvent is evaporated and dried, so it is not suitable for storing the prepared prepreg. is an I&suitable curing agent. These curing agents have a total amount of bisphenol A epoxy resin of about 1N10 parts, preferably about 3 parts.
It is used at a ratio of ~6 parts by weight.

Examples of the dialkylurea ft conductor represented by the above general formula and used as a curing accelerator include 3-phenyl-
1,1-dimethylurea, 3 (p-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(Q-
methylphenyl) -1,1-dimethylurea, 3-(
p-methylphenyl”) -1,1-dimethylurea,
3-(methoxyphenyl)-1,1-dimethylurea,
3-trophenyl)-1,1-dimethylurea, 3-
(p-chloro7enyl)L')-111-cy7lylylurea, 3yenyl-1,1-diethylurea, and the like are used. It is thought that these curing accelerators decompose at relatively low temperatures to produce dimethylamine, which exerts a strong curing accelerating effect. The amount used is about 1 to 102 parts, preferably about 3 to 6 parts, per 100 parts by weight of the total amount of bisphenol A epoxy resin.

Each of the above ingredients is an essential ingredient, and optional ingredients such as a flexibility imparting agent such as rubber, an inorganic filler such as silica, a silane coupling agent, an antifoaming agent, and a leveling agent are added as necessary. The epoxy resin composition of the present invention is prepared by dissolving solid to semi-solid and liquid bisphenol A type epoxy resins in a solvent such as methyl ethyl ketone, amethane, or toluene, and adding dimethylformamide or dimethylacetamide to this solution. , methyl cellosolve, methyl ethyl ketone, butyl cellosolve, and adding a solution of a curing agent and a curing accelerator dissolved in a solvent such as ethanol.

The epoxy tree fertilizer composition prepared in this manner can be used as reinforcing materials in various shapes such as woven fabrics, non-woven fabrics, and mats in which glass fibers, carbon fibers, aromatic polyamide fibers, metal fibers, etc. are aligned in one direction. It can be impregnated and used to make prepregs.

〔Effect of the invention〕

The epoxy resin composition of the present invention, which uses solid to semi-solid and liquid bisphenol A epoxy resins as the epoxy resin component, exhibits excellent properties such as low-temperature curability and reinforcing material impregnation properties. When it is used for preparing prepreg, it fully satisfies all of the properties required of the above-mentioned material. That is, when the epoxy resin composition of the present invention is used, (1) After being made into a prepreg, the change at room temperature is extremely small, and the storage stability in the prepreg state is good. (2) The impregnated product has excellent tackiness. (a) Prepreg layer line showing excellent drape properties (4) 80°C, 15
Curing time or under low temperature conditions of 100℃ and α5 hours, both of which are sufficient for practical strength at 58K.
[Example] Showing ft/EI+ Next, the present invention will be described in detail with reference to an example.

Example 1 Solid bisphenol humanoid epoxy resin (Mitsui Petrochemicals R-301 + epoxy equivalent 4801 softening point 68°C)
80 parts (weight, same below) and liquid bisphenol A type epoxy resin (company product R-140; epoxy resin)
fi 190, viscosity 14000 aps) in 20 parts of methyl ethyl ketone, 4 parts of dicyandiamide dissolved in 20 parts of dimethylformamide, and N-(p-chloro7enyl) H', Hl-dimethylurea. 3 parts were added to prepare an epoxy resin composition.

A glass cloth (Kanebo product is-7781-920MN) was impregnated with this epoxy resin composition, and
It was dried at ℃ for 17 minutes to produce a prepreg. Stack these 12 sheets of prepreg and sandwich them between heat presses at 80℃, L
5 hours or 100℃, 0.5 hours (pressure is 1
It was cured under the following conditions: Evaluations and measurements of physical properties were carried out as described below, and in addition, rXB
The bending strength based on K-6911 was measured as follows.

(@Ifi) 80℃, 15:00! I (FMjlt
) 57.74 copies M#, LO time
645 100℃, 20 minutes 31.01130
Minutes 5 & 0 130°C, 10 minutes 65.0 Example 2 In Example I, the amount of the epoxy resin composition was changed as follows.

Solid bisphenol A is converted into epoxy resin (R-301)
70 parts liquid bisphenol A type epoxy resin (R-1
40) 30 methyl ethyl naton
25 dicyandiamide
4N-(p-Riphenyl)w',"-gmethylurea 3dimethylformamide
20 Example 3 In Example I, a prepreg was prepared using carbon xess (Toreka 6341 manufactured by Toshi Products) as a reinforcing material instead of glass cloth, and 8 sheets of this prepreg were stacked and cured by hot press.

Comparative Example 1 In Example I, the amount of the epoxy resin composition was changed as follows.

Solid bisphenol A type epoxy resin (R-301)
80 @Liquid bisphenol A type epoxy resin (R-140) 20 Methyl ethyl naton
60 Diaminodiphenylmethane
10 Comparative Example 2 In Example 1, the amount of the epoxy resin composition was changed as follows.

Solid bisphenol A type epoxy resin (K-301)
100 g methyl ethyl ketone
20 dicyandiamide
4N,N-benzyldimethylamine
0.2 dimethylformamide
20 Comparative Example 3 In Example 1, the amount of the epoxy resin composition was changed as follows.

Liquid bisphenol hFJ epoxy resin (R-140
)20 methyl ethyl ketone
20 methyl hexahydro 7 talic anhydride 7
5N, M-benzyldimethylamine
The storage stability, tackiness and drapability of the prepregs obtained in each example and comparative example of 0.2 or more were
The strengths of the cured laminated products were also measured. The results obtained are shown in the following table.

[Evaluation method]

◎: Lifts up and hardly any resin sticks to the fingertips. 7) Δ: about the size of a cow x 8 An agent that does not sag under its own weight Patent Attorney Yoshi 1) Toshio Procedural Amendment An (Seijyu May 28, 1985)

Claims (1)

[Claims] 1. Epoxy resin, dicyandiamide or its derivatives, and general formulas ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (Here, R_1 and R_2 are lower alkyl groups, X_1 and X_2 are hydrogen atoms, halogen atom, lower alkyl group, lower alkoxy group or nitro group)
In a composition consisting of a dialkyl urea derivative represented by
00, solid to semi-solid bisphenol A type epoxy resin with a softening point of about 60 to 105°C and epoxy equivalent 1
75-250, viscosity approximately 8000-50000 cps (2
An epoxy resin composition in which both a liquid bisphenol A type epoxy resin and a liquid bisphenol A type epoxy resin (5°C) were used.