JPH05295083A - Epoxy resin composition for mold and resin mold made thereof - Google Patents

Abstract

PURPOSE:To provide an epoxy resin composition for mold curable at room temperature, having a low cure shrinkage and free from warpage and to provide a resin mold produced therefrom. CONSTITUTION:A resin mold is produced by curing an epoxy resin composition for mold composed of (A) an epoxy resin consisting of 30-60wt.% of a triphenolmethane-type epoxy resin and 40-70wt.% of hexahydrophthalic anhydride diglycidyl ester and (B) an aliphatic diamine hardener.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an epoxy resin composition for molds and a resin mold obtained by curing the composition.

[0002]

2. Description of the Related Art A method of casting a thermosetting resin such as unsaturated polyester into a mother mold and curing the resin to produce a molded product is often used. As the type of matrix used at this time,
There are metal type, gypsum type and resin type. Among them, the metal mold has excellent durability and is suitable for mass production, but is not suitable for trial manufacture and small-scale production because the manufacturing cost is high. The gypsum mold is inexpensive and easy to manufacture, but it is not suitable for manufacturing a product that requires a complicated shape or a mirror surface because it is brittle and easily damaged, and its surface is rough. Therefore, it is well known that a resin mold is often used for the purpose of trial manufacture and small-scale production, and an epoxy resin is used as a material of the resin mold. However, the conventionally used epoxy resins have the drawbacks of large curing shrinkage, low dimensional accuracy, and warpage, and the warpage is a serious problem especially when a large molded product is produced. Furthermore, if the material of the master is a wooden mold or a plastic with a low softening point,
It is necessary to make the master mold at room temperature (when heated, the water in the wood mold will precipitate, which is not preferable, and in the case of plastics with a low softening point, the master will deform), and in that case sufficient strength and There is a problem that heat resistance is not obtained and it breaks when the master is removed from the master mold in the process of making the master mold, or when the thermosetting resin is cured and molded, it is deformed by reaction heat, etc. I haven't got a resin mold.

[0003]

It is desired to develop a mold epoxy resin composition and a resin mold which can be cured at a low temperature, have a small curing shrinkage, have no warpage, and are excellent in heat resistance and physical performance.

[0004]

The present inventors have completed the present invention as a result of intensive studies to solve the above-mentioned problems. That is, the present invention includes (1) a. Triphenol methane type epoxy resin 30〜
Epoxy resin comprising 60% by weight of hexahydrophthalic anhydride diglycidyl ester 40 to 70% by weight b. Epoxy resin composition for mold comprising aliphatic diamine curing agent (2) The aliphatic diamine curing agent according to (1) above is 3-aminomethyl-3,5,5-trimethylcyclohexylamine and bis (4-amino-3-methylcyclohexyl)
Epoxy resin composition for mold according to item (1), which is methane (3) A resin mold obtained by curing the epoxy resin composition for mold according to item (1) or (2).

The epoxy resin used in the present invention comprises a mixture of a polyfunctional triphenolmethane type epoxy resin and a difunctional hexahydrophthalic anhydride diglycidyl ester. The polyfunctional triphenol methane type epoxy resin used in the present invention has the formula (1)

[0006]

[Chemical 1]

A polyfunctional solid epoxy resin represented by the formula (1) wherein R is hydrogen or an alkyl group having 10 or less carbon atoms, m is 1, 2 or 3 and n is 0 or an integer. The amount used is within the above range, but if the amount used is more than the range of the present invention, the viscosity becomes too high and the workability is significantly deteriorated, and bubbles are entrained in the resin mold which is a cured product, which is not preferable. Further, when the amount used is less than the range of the present invention, the heat resistance is deteriorated, the curing shrinkage is increased, the dimensional accuracy is deteriorated, and the warpage is likely to occur, which is not preferable. Hexahydrophthalic anhydride diglycidyl ester is a low-viscosity bifunctional epoxy resin with slightly poor heat resistance and slightly large curing shrinkage, but it has excellent workability, and has excellent performance when combined with the above-mentioned triphenolmethane type epoxy resin. A composition can be obtained. The mixing ratio of the triphenol methane type epoxy resin and the hexahydrophthalic anhydride diglycidyl ester is used in the above range, but more preferable ratios are 40 to 50% by weight for the former and 50 to 60% by weight for the latter.

The preferred aliphatic diamine curing agent used in the present invention is 3-aminomethyl-3,5,
5-Trimethylcyclohexylamine and bis (4-amino-3-methylcyclohexyl) methane are commercially available under the trade names of isophoronediamine for the former and laromin C-260 for the latter. The amount used is 0.8 to 1.2 chemical equivalents, preferably 0.9 to 1.0 chemical equivalents, based on the epoxy resin.

The mold epoxy resin composition of the present invention is used without a filler when the transfer surface of the resin mold requires a mirror surface, but is usually used with a filler added. Examples of the type of filler used include aluminum powder, copper powder, silica powder, alumina powder and the like, and the addition amount thereof is 50 to 80% by weight of the total weight of the resin composition, preferably 60 to
Add 70% by weight. The mold epoxy resin composition of the present invention uniformly stirs a predetermined amount of the above-mentioned epoxy resin, aliphatic diamine curing agent and, if necessary, filler, coupling agent, curing accelerator and colorant using a vacuum kneader. Easily obtained by the thing. The resin mold can be prepared by pouring the obtained epoxy resin composition into a mold in which a master is set, defoaming, curing at room temperature for 5 hours to 1 day, and then removing the master. The obtained resin mold can be used as it is, but a resin mold having more excellent properties can be obtained by after-curing at 60 to 150 ° C. for 3 to 20 hours. The resin mold obtained by the present invention is characterized by less shrinkage during curing, excellent dimensional accuracy, and less warpage.

[0010]

The present invention will be described in more detail with reference to the following examples.

Example 1 A polyfunctional epoxy resin represented by the formula (1) (R = H, n:
0-2 mixture, EPPN501, Nippon Kayaku Co., Ltd., epoxy equivalent 165) 500 g, hexahydrophthalic anhydride diglycidyl ester (AK-601, Nippon Kayaku Co., Ltd.,
Epoxy equivalent 152) 500 g, 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophoronediamine, manufactured by Fils) 270 g and aluminum powder 1900 g (VA-300, manufactured by Yamaishi Metal Co., average particle size 3)
5 micron) was uniformly stirred with a vacuum kneader to obtain 3170 g of the mold epoxy resin composition of the present invention (viscosity at 25 ° C., 310 poise). The obtained mold epoxy resin composition,
Test master (ABS, 250 mm x 250 mm x
20 mm) and cast into a formwork (300 mm x 300 mm x 50 mm) to defoam, then at room temperature 24
Hardened for hours. Then, the mold and the master were removed to obtain a resin mold. The resin mold thus obtained showed almost no shrinkage and no warpage was observed. Further, an unsaturated polyester was polymerized and molded using this resin mold, but no deformation (warping) of the resin mold due to reaction heat was observed.

Example 2 3-Aminomethyl-3,5,5-trimethylcyclohexylamine (isophoronediamine, used in Example 1)
270 g instead of 270 g of Fils Inc., bis (4-amino-3-methylcyclohexyl) methane (Laromin C-
260, manufactured by BASF Corp.) 3260 g of the mold epoxy resin composition of the present invention in the same manner as in Example 1 except that 360 g is used.
Was obtained (viscosity of 280 poise at 25 ° C.). Using the obtained epoxy resin composition for molds, a resin mold was obtained in the same manner as in Example 1. The resin mold thus obtained showed almost no shrinkage and no warpage was observed. Further, an unsaturated polyester was polymerized and molded using this resin mold, but no deformation (warping) of the resin mold due to reaction heat was observed.

Example 3 1270 g of the mold epoxy resin composition of the present invention was obtained in the same manner as in Example 1 except that the aluminum powder used in Example 1 was not used but only the epoxy resin and the curing agent were used. 25 ° C
Viscosity of 13 poise). Using the obtained epoxy resin composition for a mold, a resin mold was obtained in the same manner as in Example 1, and further 10
After-curing was performed at 0 ° C. for 3 hours. The resin mold obtained had excellent transferability on the master surface and had a shrinkage ratio of 0.15.
%, No warpage was observed. Further, an unsaturated polyester was polymerized and molded using this resin mold, but no deformation (warping) of the resin mold due to reaction heat was observed.

[0014]

EFFECTS OF THE INVENTION When cured at room temperature, curing shrinkage is small, dimensional accuracy is excellent, and it is possible to manufacture a resin mold without warping, which is economical and economical.
Resin molding with excellent reliability has become possible.

Claims (3)

[Claims] 1. A. An epoxy resin composed of 30 to 60% by weight of a triphenol methane type epoxy resin and 40 to 70% by weight of hexahydrophthalic anhydride diglycidyl ester. b. Aliphatic diamine curing agent. An epoxy resin composition for molds comprising. 2. The aliphatic diamine curing agent according to claim 1 is 3
The epoxy resin composition for molding according to claim 1, which is -aminomethyl-3,5,5-trimethylcyclohexylamine and bis (4-amino-3-methylcyclohexyl) methane. 3. A resin mold obtained by curing the epoxy resin composition for mold according to claim 1.