JPH0525253A - Epoxy resin composition - Google Patents

Abstract

(57) [Summary] (Modified) [Structure] (A) Low-viscosity epoxy resin containing a trifunctional or tetrafunctional liquid epoxy resin and having a viscosity at 25 ° C. of 100 poise or less, (B) liquid acid anhydride system Curing agent,
(C) An epoxy resin composition obtained by blending a curing accelerator, and a metal powder surface-treated with at least one of thiol-S-triazine and its derivatives, and the blending amount of the metal powder is the same as that of the component (A). It is 100 parts by weight or more based on 100 parts by weight of the total amount of the component (B). As the trifunctional or tetrafunctional liquid epoxy resin, triglycidyl aminophenol, tetraglycidyl xylene diamine, etc. are used, and as the liquid acid anhydride curing agent, methyl hexahydrophthalic acid, etc. are used. [Effect] Since this epoxy resin composition has a low curing shrinkage and a high strength and thermal conductivity of the cured product, an epoxy resin for producing a resin model or mold for casting, a resin mold for resin molding, etc. Excellent as a resin composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition containing a large amount of metal powder which gives a cured product having high strength and thermal conductivity and low curing shrinkage. It can be advantageously used in the production of resin models, molds, resin molds for resin molding, various jigs, and various molded products.

[0002]

2. Description of the Related Art It is already known that an epoxy resin composition prepared by mixing an epoxy resin with a metal powder such as aluminum powder is used for producing a resin model for casting, a mold, and a resin mold for resin molding. For example, Japanese Examined Patent Publication No. 50-3860
No. 6 discloses that 20 parts per 100 parts by weight of epoxy resin
It is described that a resin material obtained by mixing 40 to 60 parts by weight of aluminum powder of 0 to 500 mesh and 10 to 20 parts by weight of a curing agent is molded into an appropriate shape to obtain a casting resin model. However, since this resin model has a low aluminum powder content, the curing shrinkage rate of the resin model is large, and the prototype cannot be faithfully reproduced. Also, since the content of aluminum powder is low, the thermal conductivity is low,
The model is likely to be distorted, and it is necessary to cure while gradually raising the temperature in order to prevent the distortion, and there is a drawback that workability is poor.

Further, JP-A-60-137623 describes that a resin mold for injection molding is produced by using an epoxy resin, and metal powder such as aluminum powder or iron powder is used as a filler. It is described that a relatively large amount is blended to improve the curing shrinkage rate and thermal conductivity of the resin type. Since this resin type uses an amine-based curing agent as a curing agent and a bisphenol A type epoxy resin as an epoxy resin, the resin composition has a high viscosity and is relatively used as a metal powder such as an aluminum powder to be blended. Had to use a large particle size. Moreover, when metal powder having a large particle size is used, not only the surface characteristics of the obtained resin molded product, such as the finished surface of the resin mold, are difficult, but also the metal powder is not uniformly dispersed, so that the resin composition precipitates and separates. There was a defect such as causing.

Further, in Japanese Patent Laid-Open No. 2-53850,
To a low-viscosity epoxy resin containing an alicyclic epoxy resin and having a viscosity of 50 poise or less, 5 fine powders having a particle size of 44 μm or less are used.
By adding 100 parts by weight or more of metal powder containing 0% by weight or more to 100 parts by weight of the total amount of the epoxy resin and the curing agent, a cured product having a low curing shrinkage and a high thermal conductivity is obtained. However, this epoxy resin composition is not satisfactory in terms of strength of the cured product.

On the other hand, the resin mold is advantageous in terms of easiness of manufacture and cost as compared with a mold, but the strength of the mold is low,
There is a defect that an accident such as chipping or breakage of the mold itself is likely to occur during cutting of the mold or repeated use of the mold, and a resin mold having high strength and durability is required.

[0006]

DISCLOSURE OF THE INVENTION The present invention overcomes the above-mentioned problems of the prior art, namely, a cured product having a small curing shrinkage, a high thermal conductivity, and excellent strength and durability,
In particular, it is intended to provide an epoxy resin composition which can give various resin types.

The present inventors have conducted various studies in order to solve the above-mentioned problems, and as a result, trifunctional or tetrafunctional low-viscosity liquid epoxy resin, liquid acid anhydride curing agent, curing accelerator, and The object could be achieved by the epoxy resin composition containing a large amount of metal powder treated with thiol-S-triazine.

That is, the epoxy resin composition of the present invention comprises (A) a low-viscosity epoxy resin containing a trifunctional or tetrafunctional liquid epoxy resin and having a viscosity at 25 ° C. of 100 poise or less, and (B) a liquid acid anhydride. System curing agent, (C) curing accelerator, and (D) metal powder surface-treated with at least one selected from thiol-S-triazine and its derivatives, and the amount of component (D) compounded Is a metal powder in an amount of 100 parts by weight or more based on 100 parts by weight of the total amount of the components (A) and (B).

(Epoxy resin) Used in the present invention (A)
The low-viscosity epoxy resin is a low-viscosity epoxy resin containing a trifunctional or tetrafunctional liquid epoxy resin and having a viscosity at 25 ° C. of 100 poise or less. As the trifunctional or tetrafunctional liquid epoxy resin, various types can be used, but particularly preferred are trifunctional triglycidyl aminophenol, tetrafunctional tetraglycidyl xylene diamine, and 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane, tetraglycidylaminodiphenylmethane and the like can be mentioned. These liquid epoxy resins may be used alone or in combination of two or more. In the present invention, since a trifunctional or tetrafunctional epoxy resin is used, the strength of the cured product is significantly higher than that when a bifunctional epoxy resin is used.

The low viscosity epoxy resin used in the present invention is
It may be composed only of the above-mentioned trifunctional or tetrafunctional epoxy resin, and if necessary, the trifunctional or tetrafunctional epoxy resin may be replaced with another epoxy resin such as bisphenol A type epoxy resin or bisphenol F type epoxy resin. It may be a mixture of an aromatic ring-containing epoxy resin such as an epoxy resin.

(Liquid Acid Anhydride Curing Agent) The liquid acid anhydride curing agent (B) used in the present invention has a viscosity at 25 ° C. among ordinary acid anhydride curing agents for epoxy resins. Anything below 100 poise can be used. For example, an isomer mixture of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride,
Examples thereof include alicyclic dibasic acid anhydrides such as 3,6-endomethylenemethyltetrahydrophthalic anhydride; long-chain alkenylsuccinic anhydrides such as dodecenylsuccinic anhydride. Of these, the viscosity at 25 ° C is 10
A cycloaliphatic dibasic acid anhydride of 0 centipoise or less is preferable.

The amount of the liquid acid anhydride-based curing agent used in the present invention is in the range of a generally used amount, for example, the equivalent ratio of the acid anhydride group of the acid anhydride to the epoxy group of the epoxy resin is 6/10. Used at a rate of ~ 12/10. In general, in the case of acid anhydride-based curing agents, the amount of the curing agent itself is larger than that of amine-based curing agents, so that it becomes possible to add a large amount of metal powder, which in turn causes curing shrinkage of the cured product. It can contribute to the reduction of the coefficient and the improvement of the thermal conductivity.

(Curing accelerator) Examples of the curing accelerator (C) used in the present invention include 2-ethyl-4-methylimidazole, 1-cyanoethyl-4-methylimidazole, 1-benzyl-2-ethylimidazole and the like. Imidazoles, trisdimethylaminomethylphenol,
Examples include tertiary amines such as 2,4,6-tris (dimethylamino) phenol and dimethylcyclohexylamine. By using the curing accelerator, low temperature curing can be performed and curing time can be shortened. The amount of the curing accelerator used is usually selected so that it can be cured at a temperature of 80 ° C. or lower at an economical curing rate (curing time), and the amount of the curing accelerator usually used is 100% by weight. It is 1 to 5 parts by weight with respect to parts by weight.

(Surface-treated metal powder) The epoxy resin composition of the present invention contains (D) metal powder surface-treated with at least one selected from thiol-S-triazine and its derivatives. Examples of the metal powder include aluminum powder, copper powder, iron powder, nickel powder, and chrome powder.

Thiol used for surface treatment of metal powder
Examples of S-triazine and its derivative include 2,
4,6-Trimercapto-S-triazine, 2-dibutylamino-4,6-dimercapto-S-triazine, 2
-Anilino-4,6-dithiol-S-triazine and the like.

The surface treatment of metal powder with thiol-S-triazine and its derivative (hereinafter referred to as "thiol-S-triazines") in the present invention is carried out by thiol-S.
-A method of immersing the metal powder in a solution or dispersion of triazines in water or an organic solvent, or spraying or coating the solution or dispersion on the surface of the metal powder is used. Surface treatment of the metal powder with thiol-S-triazines can significantly improve the strength and durability of the cured epoxy resin product. Although the reason is not always clear, it is presumed that the thiol-S-triazines may be a primary bond or a secondary bond to one or both of the metal powder and the epoxy resin.

The mixing ratio of the metal powder surface-treated with the thiol-S-triazines in the present invention is 100 parts by weight or more, preferably 100 parts by weight as the metal powder based on 100 parts by weight of the total amount of the components (A) and (B). Is 150 to 300 parts by weight. By blending a large amount of metal powder in this way, the curing shrinkage can be lowered, and the precision of the mold can be improved when used as various resin molds. Further, when the blending amount of the metal powder is increased, the thermal conductivity of the cured product is increased, the strain is less likely to occur, the mold retention is improved, and the curing speed at the time of curing can be increased, and the workability of curing is improved. Can be improved.

In addition to the components (A) to (D) described above, various additives may be added to the epoxy resin composition of the present invention, if necessary, within a range that does not impair the desired physical properties of the resin composition. Agents such as flame retardants, thixotropic agents, reactive diluents, leveling agents, lubricants, anti-settling agents, defoamers, dispersants, coupling agents, dyes, pigments, rust inhibitors, etc. can be added. .

The epoxy resin composition of the present invention is prepared by mixing the above-mentioned essential components (A) to (D) and, if necessary, additives to be blended by an appropriate method and kneading. However, for the kneading, for example, a kneader, a roll, a mixer or the like can be appropriately used.

The epoxy resin composition of the present invention can be heat-cured by a suitable method. For example, 100 ~
You may make it harden | cure by 1 step hardening which heats at 180 degreeC for 4 to 15 hours, or it may heat at 50 to 80 degreeC for 5 to 10 hours to make primary hardening, and then at 130 to 180 degreeC for 2 to 6 hours to make secondary. It may be cured by two-stage curing.

[0021]

[Examples] Examples and comparative examples will be described in more detail below.

Example 1 100 g of triglycidyl aminophenol, and 2,
350 g of the surface-treated aluminum powder (average particle size 15 μm), which had been immersed in a 1% by weight methanol solution of 4,6-trimercapto-S-triazine at room temperature for 60 minutes, was mixed and kneaded with a kneader. Next, to 100 g of this mixture, 80 g of methyltetrahydrophthalic anhydride as a curing agent and 2 g of 2-ethyl-4-methylimidazole as a curing accelerator were added and mixed uniformly, and cured at 120 ° C. for 8 hours. The results of testing the flexural strength and thermal conductivity of this cured product are as shown in Table 1.

Example 2 Triglycidyl aminophenol 10 used in Example 1
Instead of 0 g, 50 g of tetraglycidyl xylylenediamine (Mitsubishi Gas Chemical Co., Ltd., trade name Tetrado X) and 80 g of bisphenol F glycidyl ether (Yukaka Ciel Epoxy Co., Ltd., trade name Epicote 807) were used, and otherwise the same as in Example 1. An epoxy resin composition was prepared by the method described in 1. above and cured in the same manner. The results are shown in Table 1.

Example 3 Instead of 350 g of the aluminum powder treated with 2,4,6-trimercapto-S-triazine used in Example 1, 2-dibutylamino-4,6-dimercapto-S- was used.
An epoxy resin composition was prepared in the same manner as in Example 1 except that 330 g of aluminum powder (average particle size: 15 μm) treated with triazine in the same manner was used as the aluminum powder. It was cured by the method. The results are shown in Table 1.

Comparative Example 1 Triglycidyl aminophenol 10 used in Example 1
Instead of 0 g, bisphenol F diglycidyl ether (Yukaka Shell Epoxy Co., Ltd. trade name Epicoat 80
7) An epoxy resin composition was prepared in the same manner as in Example 1 except that 160 g was used, and the composition was cured by the same method. The results are shown in Table 1.

Comparative Example 2 Instead of 350 g of 2,4,6-trimercapto-S-triazine-treated aluminum powder used in Example 1, 350 g of surface-untreated aluminum powder (average particle size 20 μm) was used. An epoxy resin composition was prepared in the same manner as in Example 1 except that the above composition was used and the composition was cured in the same manner. The results are shown in Table 1.

[0027]

[Table 1]

As is clear from Table 1, the cured products of Examples have higher flexural strength and thermal conductivity than the cured products of Comparative Examples.

[0029]

The epoxy resin composition of the present invention has a low curing shrinkage ratio and a high strength and thermal conductivity of the cured product. Therefore, the epoxy resin composition for casting, the epoxy resin for producing a resin mold for resin molding, etc. Excellent as a resin composition.

Claims (2)

[Claims] 1. A low-viscosity epoxy resin containing (A) a trifunctional or tetrafunctional liquid epoxy resin and having a viscosity at 25 ° C. of 100 poise or less, (B) a liquid acid anhydride-based curing agent, and (C) a curing accelerator. Agent, and (D) a metal powder surface-treated with at least one selected from thiol-S-triazine and its derivative, and the blending amount of the (D) component is the (A) component and the (B). An epoxy resin composition which is 100 parts by weight or more as a metal powder with respect to a total amount of 100 parts by weight of components. 2. A trifunctional to tetrafunctional liquid epoxy resin is triglycidyl aminophenol, tetraglycidyl xylene diamine, tetraglycidyl aminodiphenyl methane and 1,3-bis (N, N'-diglycidyl aminomethyl) cyclohexane. At least one selected from
The epoxy resin composition according to claim 1, which is a seed.