JP3069556B2 - Epoxy resin composition for jigs and tools and epoxy resin mold - Google Patents

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 for producing jigs and tools by electric discharge machining in which a large amount of metal powder is contained in an epoxy resin and an epoxy resin mold formed using the same. About. In particular, molds for repairing various jigs (eg, inspection jigs, jigs for punching and cutting, etc.) and metal equipment and parts (eg, master models, mechanical parts, etc.) or manufacturing various parts. TECHNICAL FIELD The present invention relates to an epoxy resin composition for producing jigs and tools by electric discharge machining, which contains metal powder capable of being used, and an epoxy resin mold formed using the composition.

[0002]

2. Description of the Related Art Parts such as automobile doors and hoods are
It is manufactured by press forming a steel plate using a press die. Also, plastic parts such as automobile bumpers are manufactured by injection molding using an injection molding die. Since these dies are expensive, non-ferrous alloy dies such as zinc, aluminum and copper are used as dies for trial production of parts or small-scale production for special specifications. One of the non-ferrous alloy molds, the zinc-based alloy mold by the precision casting method, can obtain almost the precision as designed when manufacturing small ones, but it can be cast when manufacturing large ones. There was a problem that distortion was large and it was difficult to maintain accuracy.

In order to solve this problem, resin molds have been used instead of metal molds. The resin mold is manufactured as follows. That is, a rough mold is manufactured using a zinc-based alloy that has a low melting point and can be melted and reused, and a skin resin layer is formed on the surface by casting to form a mold. For the production of this resin mold, a zinc-based alloy rough mold can be reused, so that the cost of the mold can be reduced. As a casting resin used for manufacturing such a resin mold, an epoxy resin containing a metal powder such as iron powder is generally used.

On the other hand, resin molds are more advantageous than metal molds in terms of ease of production, dimensional accuracy, cost, etc.
There are drawbacks such as cracks occurring in the mold itself during cutting of the mold or during repeated use. Furthermore, while a metal mold can be machined using an electric discharge machining technique that is advantageous for speeding up machining of the mold, a resin mold has insufficient conductivity, so the electric discharge machining technique is used. And it cannot be processed. Therefore, the appearance of a resin mold having high strength, excellent durability in repeated use, and conductivity capable of utilizing electric discharge machining technology is desired, but a resin mold satisfying this requirement can be obtained. At present, there is no epoxy resin material.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. Therefore, the object of the present invention is, in particular,
Strength is large, excellent durability in repeated use, there utilizing EDM technology resin form to provide a jig for epoxy resin composition which can be made by casting. Another object of the present invention is to provide an epoxy resin mold formed by casting, curing , and electric discharge machining the epoxy resin composition.

[0006]

According to the electric discharge machining of the present invention,
An epoxy resin composition for producing a jig and a tool contains at least an epoxy resin, a metal powder and a carbon fiber, the carbon fiber having a fiber length of 0.1 to 10 mm, and an epoxy resin based on the total amount of the epoxy resin composition. Resin content of 14.9-39.9% by weight, metal powder content of 60-8
5% by weight and carbon fiber content of 0.1 to 10% by weight
And has a viscosity at 50 ° C. of 5 to 200 Pa ·
and at least epoxy resin, metal powder and carbon fiber, which are in the range of s. The epoxy resin mold of the present invention is manufactured using electric discharge machining.
Be one that is manufactured, the composition obtained by mixing the epoxy resin composition and an epoxy resin curing agent is cast, cured
And, Ru is produced by electrical discharge machining.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Jig and tool production by electric discharge machining according to the present invention
The epoxy resin composition for manufacturing (hereinafter, "epoxy jigs
Resin composition ". As the epoxy resin, which is one of the constituent components of (1 ) , a low-viscosity liquid epoxy resin can be preferably used. Specific examples of the low-viscosity liquid epoxy resin include bifunctional bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol AD diglycidyl ether, tetramethyl bisphenol A diglycidyl ether, tetramethyl bisphenol F diglycidyl ether, and tetramethyl. Bisphenol AD diglycidyl ether, tetramethylbisphenol S diglycidyl ether, 3
Functional triglycidylaminophenol, triglycidylaminocresol, tetrafunctional tetraglycidylxylenediamine, 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane, tetraglycidylaminodiphenylmethane, etc., are examples of the present invention. However, it is not limited to these. In the present invention, two or more of these epoxy resins may be used in combination.

In the case of producing a cast product having a fine shape, the lower the viscosity of the epoxy resin composition for jigs and tools, the better the workability. Therefore, the present invention provides an epoxy resin composition for jigs and tools. For the purpose of lowering the viscosity, a liquid epoxy resin generally called a reactive diluent can be used in combination. Specific examples of the liquid epoxy resin include Rikaresin DME-100, Rikaresin DME-200, Rikaresin W-100, and Rikaresin L manufactured by Shin Nippon Rika Co., Ltd.
-200, Lica Resin L-400, Epolite 40E, Epolite 400E, Epolite 70 manufactured by Kyoeisha Chemical Co., Ltd.
P, Epolite 400P, Epolite 1500NP, Epolite 1600, Epolite 80MF, Epolite 1
00MF, YED111, Y manufactured by Yuka Shell Epoxy
ED111A, YED111E, YED122, YED
205, YED216 Epicron 520, Epicron 703, manufactured by Dainippon Ink and Chemicals, B, manufactured by Yokkaichi Gosei Co., Ltd.
GE and the like, but the present invention is not limited to these.

In the present invention, the content of the epoxy resin is 14.9 to 3 with respect to the total amount of the epoxy resin composition.
It must be in the range of 9.9% by weight. When the content of the epoxy resin is less than the above range, the workability deteriorates because the fluidity of the epoxy resin composition decreases, and when the content is more than the above range, the epoxy resin composition , The curing shrinkage ratio becomes large, and a cured product with high dimensional accuracy cannot be obtained. Further, the content of the liquid epoxy resin as the reactive diluent is preferably in the range of 10% by weight or less based on the total amount of the epoxy resin composition. If the content is more than this range, the strength of the cured product decreases.

The metal powder, which is another component of the epoxy resin composition for jigs and tools of the present invention, acts to improve the wear resistance and thermal conductivity of the epoxy resin composition for jigs and tools. is there. Examples of the metal powder include powders of various metals such as aluminum powder, copper powder, iron powder, nickel powder, and chromium powder, and powders of two or more alloys of these various metals. Among them, aluminum powder is preferably used in the present invention because it has excellent wettability with an epoxy resin and has an advantage that the specific gravity is small and the cured resin can be reduced in weight.

In order to improve the dispersibility of the metal powder in the epoxy resin, a surface treatment agent (for example, a silane-based or titanium-based coupling agent, a triazine thiol-based compound, etc.) is used for the surface treatment in advance. May be done.

In the present invention, the average particle size of the metal powder is not particularly limited, but is preferably 100 μm.
Hereinafter, those having a range of 10 to 50 μm are more preferably used. When the particle size of the metal powder is large, when the epoxy resin composition is used as a resin mold, the finish of the casting surface of the metal product becomes poor, or the metal powder is contained in the epoxy resin composition for jigs and tools. In order not to disperse evenly,
The storage stability of the epoxy resin composition for jigs and tools deteriorates,
Furthermore, the surface properties of the cured product are reduced. In addition, it is preferable that the metal powder has a wider particle size distribution than the narrow particle size distribution because the viscosity of the epoxy resin composition for jigs and tools is easily reduced. Therefore, it is desirable to use a mixture of a plurality of metal powders having different average particle sizes.

The content of the metal powder in the epoxy resin composition for jigs and tools of the present invention must be in the range of 60% by weight to 85% by weight based on the total amount of the epoxy resin composition. The abrasion resistance of the cured product of the epoxy resin composition for tools can be improved. When the content ratio of the metal powder is less than the above range, the effect of improving the abrasion resistance of the cured product of the epoxy resin composition cannot be obtained, and the strength and durability are reduced. On the other hand, when the content ratio of the metal powder is larger than the above range, the workability is deteriorated because the fluidity of the epoxy resin composition is reduced.

Further, when a cured product requiring strict dimensional accuracy or a precise cast product is produced using the epoxy resin composition for jigs and tools of the present invention, the curing shrinkage ratio It is particularly preferable that the mixing ratio of the metal powder be in the range of 70 to 80% by weight with respect to the total amount of the epoxy resin composition for jigs and tools, for the purpose of reducing the flow rate and ensuring fluidity. Thereby, the thermal conductivity of the epoxy resin composition for jigs and tools is improved, and the curing shrinkage is reduced, whereby the dimensional accuracy of the cured product is increased, and the occurrence of cracks due to an increase in distortion is less likely to occur. .

The carbon fiber, which is still another component of the epoxy resin composition for jigs and tools of the present invention, exhibits the effect of reinforcing the epoxy resin composition for jigs and tools and improving the conductivity. As long as the carbon fiber is generally used as a reinforcing material for a composite material, any of a pitch-based carbon fiber and a polyacrylonitrile-based (PAN-based) carbon fiber may be used. Examples of pitch-based carbon fibers include Kureka manufactured by Kureha Chemical Industry Co., Ltd., Dialead manufactured by Mitsubishi Chemical Corporation, Donacarbo S and Donacarbo F manufactured by Donac, and examples of PAN-based carbon fibers include Toray Industries, Inc. Trader manufactured by Toho Rayon Co., Ltd .; Vesophile manufactured by Mitsubishi Rayon Co., Ltd .; Magnumite manufactured by Hercules Co., Ltd .; There is no particular limitation on the fiber diameter of the carbon fiber used,
If the fiber diameter is too large, the fluidity of the epoxy resin composition for jigs and tools and the surface properties of the cured product decrease, so that
m or less.

In the present invention, carbon fibers having a fiber length of 0.1 to 10 mm obtained by cutting a raw yarn are used. When the fiber length is longer than 10 mm, not only the dispersibility in the epoxy resin becomes poor, but also the viscosity of the epoxy resin composition for jigs and tools increases. Fiber length is 0.1mm
If it is shorter than this, the reinforcing effect cannot be obtained. Further, as carbon fibers, curled fibers are more preferable than straight fibers.
This is because the use of the curled fibers improves the entanglement between the fibers in the epoxy resin composition for jigs and tools, so that a greater reinforcing effect and an improved conductivity can be expected as compared with straight fibers.

It is also possible to use carbon fibers which have been subjected to a surface treatment in advance. Those that have been subjected to a surface treatment by oxidation treatment, plasma treatment, or the like, or those that use a surface treatment agent such as a coupling agent can also be used.
Various surface treatments of the fiber are well-known techniques and will not be described in detail.

In the present invention, the content of carbon fiber is 0.1% by weight based on the total amount of the epoxy resin composition for jigs and tools.
It needs to be in the range of 10 to 10% by weight. If the amount is less than the above range, not only the reinforcing effect of the epoxy resin composition for jigs and tools cannot be obtained, but also the effect of improving the conductivity cannot be obtained. When the amount is more than the above range, the viscosity of the epoxy resin composition increases,
The fluidity decreases, and the workability deteriorates.

The epoxy resin composition for jigs and tools of the present invention may contain, in addition to the aforementioned epoxy resin, metal powder, and carbon fiber, a reactive diluent other than the epoxy resin, such as acrylate, if necessary. Agents, antisettling agents, adhesion promoters, wetting agents, flame retardants, thixotropic agents, leveling agents, lubricants, defoamers, dispersants, coupling agents, dyes, pigments, rust inhibitors, corrosion inhibitors, Graphite,
Other various additives can be added. The content of these additives can be appropriately set.

The epoxy resin composition for jigs and tools of the present invention is prepared by appropriately mixing the above-mentioned epoxy resin, metal powder, carbon fiber, and a reactive diluent and additives to be added as necessary, and stirring and kneading. Can be performed.
For the stirring and kneading, for example, a kneader, a roll, a mixer and the like are appropriately used.

The epoxy resin composition for jigs and tools of the present invention produced in this way must have a viscosity at 50 ° C. in the range of 5 Pa · s to 200 Pa · s. When the viscosity of the epoxy resin composition is higher than the above range, when a resin mold is produced using the same, the strength and wear resistance of the cured product are improved, but the fluidity and workability are deteriorated. When the viscosity is lower than the above range, the contained metal powder and carbon fiber are settled, and it is difficult to obtain a uniform cured product.

Further, the epoxy resin composition for jigs and tools of the present invention has a curing shrinkage of not more than 0.01% when an epoxy resin curing agent is added and cast and cured. preferable. If the curing shrinkage is higher than the above case, the dimensional accuracy is reduced, and the strain is increased, and cracks are likely to occur. By appropriately adjusting the blending of the metal powder, carbon fiber, epoxy resin and additives described above, an epoxy resin composition for jigs and tools having a curing shrinkage of 0.01% or less can be easily obtained.

The epoxy resin composition for jigs and tools of the present invention comprises:
When mixed with an epoxy curing agent and cured, a cured product that can be subjected to electrical discharge machining is obtained. As the epoxy curing agent to be mixed at this time, any epoxy curing agent generally known can be used. Specific examples thereof include amines, modified amines, polyamide resins, acid anhydrides, and imidazoles. When it is necessary to cure at room temperature, it is preferable to use a polyamide resin which is excellent in curability at room temperature. One of these epoxy curing agents may be used, or two or more of them may be used in combination as appropriate. The epoxy curing agent is usually used as a mixture with the epoxy resin composition for jigs and tools of the present invention. In the case of a curing agent which is curable at room temperature, it should be mixed immediately before use of the composition. Is preferred. The addition amount of the epoxy curing agent can be appropriately set according to the epoxy resin used.

The epoxy resin composition for jigs and tools of the present invention can be cured by various methods. The curing conditions can be appropriately selected depending on the curing agent to be used, and the curing can be performed using general curing conditions for the epoxy resin. Generally, the temperature is between room temperature and 20
It is performed at 0 ° C. for a time of 1 to 30 hours, and multi-stage curing is also possible if necessary.

The cured product formed by curing the epoxy resin composition for jigs and tools of the present invention has a significantly improved strength after curing as compared with one containing no carbon fiber. The object can be machined using an electric discharge machining technique.

The epoxy resin composition for jigs and tools of the present invention obtained as described above has a low curing shrinkage, a small coefficient of linear thermal expansion, good dimensional stability and surface properties, high strength, A general-purpose electric discharge machine (as examples of electric discharge machines, A5C, A7C, A6 manufactured by sodick)
5, A10C, H7, EDNC2015-2 manufactured by Makino
H, DIAX DK360 manufactured by Mitsubishi Electric Corporation, PE-5000 manufactured by Pulse Corporation, etc.) can be used to obtain a cured product that can be subjected to electric discharge machining. Accordingly, an epoxy resin curing agent is mixed with the epoxy resin composition for jigs and tools of the present invention, cast, cured , and discharged by electric discharge machining.
By processing, a jig such as a mold made of epoxy resin can be obtained.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
In the examples, “parts” means “parts by weight”. Example 1 50 parts of aluminum powder (average particle size: 40 μm), bisphenol A-based diglycidyl ether type epoxy resin (trade name: Epicoat 825, manufactured by Yuka Shell Epoxy) 1
0.5 parts, bisphenol F-based diglycidyl ether type epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., trade name: Epicoat 806) 31.5 parts, carbon fiber having a fiber length of 3 mm (manufactured by Donac Co., trade name: Donacarbo S) -344) 3
Part, a reactive diluent, 5.0 parts of 1,4-cyclohexanedimethanol diglycidyl ether (manufactured by Shin Nippon Rika Co., Ltd., trade name: Rikaresin DME-200) mixed at 50 ° C., and an epoxy resin composition for jigs and tools. I got To 100 parts of the epoxy resin composition for jigs and tools thus obtained, 1-cyanoethyl-2-ethyl-4- was used as a curing agent.
Methyl imidazole (manufactured by Shikoku Chemicals, trade name: 2E4M
Z-CN) was added, and the mixture was uniformly mixed and defoamed at 50 ° C.
Further, the composition was heated and cured at 160 ° C. for 2 hours to obtain a cured product of the epoxy resin composition for jigs and tools.

Example 2 60 parts of aluminum powder (average particle size: 40 μm), bisphenol A diglycidyl ether type epoxy resin (trade name: Epicoat 825, manufactured by Yuka Shell Epoxy Co., Ltd.)
7.5 parts, bisphenol F-based diglycidyl ether type epoxy resin (trade name: Epicoat 806, manufactured by Yuka Shell Epoxy Co., Ltd.), 22.5 parts, carbon fiber having a fiber length of 3 mm (trade name: Donacarbo S) -231) 4
And 6 parts of 1,4-cyclohexanedimethanol diglycidyl ether (manufactured by Shin Nippon Rika Co., Ltd., trade name: Rikaresin DME-200) as a reactive diluent at 50 ° C. to obtain an epoxy resin composition for jigs and tools. Was. 7. 1-cyanoethyl-2-ethyl-4-methylimidazole as curing agent
A cured product of the epoxy resin composition for jigs and tools was obtained in the same manner as in Example 1, except that 5 parts was changed to 6.1 parts.

Example 3 71.6 parts of aluminum powder (average particle size: 40 μm), bisphenol A diglycidyl ether type epoxy resin (trade name: Epicoat 82, manufactured by Yuka Shell Epoxy Co., Ltd.)
5) 5.9 parts, bisphenol F diglycidyl ether type epoxy resin (manufactured by Yuka Shell Epoxy Co., trade name:
Epicoat 806) 17.8 parts, carbon fiber having a fiber length of 3 mm (product name: Donacarbo S-231, manufactured by Donac)
One part, 3.7 parts of 1,4-cyclohexane dimethanol diglycidyl ether (manufactured by Nippon Rika Co., Ltd., trade name: Rikaresin DME-200) as a reactive diluent was mixed at 50 ° C., and the epoxy resin composition for jigs and tools was mixed. I got something. Curing agent 1
A cured product of the epoxy resin composition for jigs and tools was obtained in the same manner as in Example 1, except that 8.5 parts of -cyanoethyl-2-ethyl-4-methylimidazole was changed to 4.9 parts.

Example 4 68.8 parts of aluminum powder (average particle size: 40 μm), bisphenol A diglycidyl ether type epoxy resin (trade name: Epicoat 82, manufactured by Yuka Shell Epoxy Co., Ltd.)
5) 5.7 parts, bisphenol F diglycidyl ether type epoxy resin (manufactured by Yuka Shell Epoxy, trade name:
Epicoat 806) 17.2 parts, carbon fiber having a fiber length of 0.96 mm (manufactured by Donac, trade name: Donacarbo S-3)
44) 2.3 parts, and 6 parts of 1,4-cyclohexanedimethanol diglycidyl ether (manufactured by Nippon Rika Co., Ltd., trade name: Rica Resin DME-200) as a reactive diluent, 50
The mixture was mixed at ℃ to obtain an epoxy resin composition for jigs and tools. Example 1 except that 8.5 parts of 1-cyanoethyl-2-ethyl-4-methylimidazole as a curing agent was changed to 5.2 parts.
In the same manner as in the above, a cured product of the epoxy resin composition for jigs and tools was obtained.

Example 5 71.4 parts of aluminum powder (average particle size: 40 μm), bisphenol A diglycidyl ether type epoxy resin (trade name: Epicoat 82, manufactured by Yuka Shell Epoxy Co., Ltd.)
5) 6.0 parts, bisphenol F diglycidyl ether type epoxy resin (manufactured by Yuka Shell Epoxy, trade name:
Epicoat 806) 17.8 parts, carbon fiber having a fiber length of 0.96 mm (manufactured by Donac, trade name: Donacarbo S-3)
44) 1.2 parts, 3.6 parts of 1,4-cyclohexanedimethanol diglycidyl ether (manufactured by Nippon Rika Co., Ltd., trade name: Rikaresin DME-200) as a reactive diluent are mixed at 50 ° C. and jigs and tools are mixed. An epoxy resin composition was obtained.
A cured product of the epoxy resin composition for jigs and tools was obtained in the same manner as in Example 1, except that 8.5 parts of 1-cyanoethyl-2-ethyl-4-methylimidazole as the curing agent was changed to 4.9 parts. .

Comparative Example 70.0 parts of aluminum powder (average particle size: 40 μm), bisphenol A diglycidyl ether type epoxy resin (trade name: Epicoat 82, manufactured by Yuka Shell Epoxy Co., Ltd.)
5) 7.5 parts, bisphenol F-based diglycidyl ether type epoxy resin (manufactured by Yuka Shell Epoxy, trade name:
22.5 parts of Epicoat 806) were mixed at 50 ° C. to obtain a comparative epoxy resin composition for jigs and tools. Curing agent 1-
A cured product of the comparative epoxy resin composition for jigs and tools was obtained in the same manner as in Example 1 except that 8.5 parts of cyanoethyl-2-ethyl-4-methylimidazole was changed to 5.4 parts.

Next, the viscosities of the epoxy resin compositions for jigs and tools described in the above Examples and Comparative Examples, the curing shrinkage during curing, and the impact strength of the cured products were measured by the following methods. Table 1 shows the results.

1. Measurement of the viscosity of the epoxy resin composition for jigs and tools The viscosity of the epoxy resin composition for jigs and tools obtained in each of Examples and Comparative Examples at 50 ° C. before the addition of the curing agent was measured using a precision circulating high-temperature water tank (Visco Thermo Cool VCH- 400, manufactured by Toki Sangyo Co., Ltd.) using an E-type viscometer (DVU-EII, manufactured by Toki Sangyo Co., Ltd.). Rotor cone angle: 1 ° 34 'Rotor cone radius: 24mm

2. Measurement of Curing Shrinkage The curing shrinkage of the epoxy resin compositions for jigs and tools in each of the examples and comparative examples was determined from the ratio of the specific gravity of each composition before curing to the specific gravity after curing. Assuming that the specific gravity before curing is Sm and the specific gravity after curing is Sp, the curing shrinkage is expressed by the following formula. The specific gravity is measured according to Japanese Industrial Standards (JIS-K
7232 epoxy resin and curing agent specific gravity test method). Curing shrinkage (%) = − (1 / Sp−1 / Sm) / (1 / Sm) × 100 = {1- (Sm / Sp)} × 100

3. Measurement of Impact Strength (50% Breaking Energy) of Cured Product A Dupont impact tester (H-200, Toyo Seiki Seisakusho) was used to conduct an impact test of a cured product of the epoxy resin composition for jigs and tools obtained in each of Examples and Comparative Examples. (Manufactured by Sharp Corporation).
From the results of this impact test, the Japanese Industrial Standards (JIS-K7
The 50% breaking energy (impact energy when 50% of the number of test pieces breaks) was determined based on 211 pyramidal impact test method of hard plastic). Test piece thickness: 5 mm Number of test pieces: 20 Weight mass: 300 parts

4. Evaluation of electric discharge machining The electric discharge machining property of the cured product of the epoxy resin composition for jigs and tools obtained in each of the examples and comparative examples was evaluated.

[0038]

[Table 1]

As is clear from the results shown in Table 1, the cured products of Examples 1 to 5 of the present invention containing carbon fibers could be subjected to electric discharge machining. The composition of Example 1 had a large curing shrinkage upon curing, and thus was not suitable for a field requiring high dimensional accuracy. However, the composition had no reduction in impact strength and was capable of electric discharge machining. Further, the compositions of Examples 2 to 5 were able to obtain cured products having higher impact strength than the cured products of Comparative Examples. In particular, since the compositions of Examples 1 and 3 to 5 had low viscosities, it was judged that the handleability during casting was good. In addition, it was shown that cast products having particularly high dimensional accuracy can be obtained from the cured products of the compositions of Example 3 and Example 5. The composition of the comparative example containing no carbon fiber had good workability, but the cured product was not only satisfactory in impact strength, but could not be subjected to electrical discharge machining,
The object of the present invention could not be achieved.

Preparation Example of Epoxy Resin Mold To each of the epoxy resin compositions for jigs and tools obtained in Examples 1 to 5 and Comparative Example, an epoxy curing agent was added in the same manner as described above.
After using a resin solution obtained by mixing and defoaming at 50 ° C. and pouring it into a mold having a frame attached to a master model,
A curing treatment was performed at 50 ° C. for 24 hours, and the master model was released from the mold to produce a fixed mold insert. Next, set the product shape type spacer on the fixed type nest with the frame attached,
After casting the same resin liquid as above, a hardening treatment was performed in the same manner to produce a movable insert. The obtained fixed and movable inserts were removed from the frame and subjected to a secondary curing treatment at 160 ° C. for 2 hours to produce fixed and movable inserts. These inserts were used as molds and assembled into a molding machine to perform resin molding. As a result, when the nested molds obtained from the epoxy resin compositions of Examples 1 to 5 were used, resin molded products having good dimensional accuracy were obtained in all cases. In addition, the durability of the nesting type is good, and in addition, when the type is changed due to a design change, etc., the nesting can be easily performed by electric discharge machining, which significantly increases the processing time and processing cost. The effect of achieving a significant reduction was achieved. On the other hand, in the case of the telescopic type obtained from the epoxy resin composition of the comparative example, the convex part of the movable type is weak in strength and is inferior in durability, and the convex part in the production of the movable type Needed to fit a metal nest. In addition, since electric discharge machining cannot be performed, it is necessary to separately prepare a nest at the changed part and fit it into a movable nest in the case of a design change, which requires considerable time and cost. Was.

[0041]

As described above, the epoxy resin composition for jigs and tools of the present invention provides a cured product having good workability, excellent dimensional accuracy, and high strength. It can be used advantageously for manufacturing. In addition, since the cured product can be subjected to electric discharge machining, precise and quick machining can be performed when a jig such as an epoxy resin mold is manufactured.

Continuation of front page (56) References JP-A-6-157718 (JP, A) JP-A-2-53850 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 63 / 00-63/10 C08K 3/08 C08K 7/06 B21D 37/01 B29C 33/40

Claims (4)

(57) [Claims] 1. An epoxy resin composition containing at least an epoxy resin, metal powder and carbon fiber, wherein the carbon fiber has a fiber length of 0.1 to 10 mm, and contains the epoxy resin with respect to the total amount of the epoxy resin composition. Amount of 14.9
３９39.9% by weight, metal powder content is 60-85% by weight
And the content of carbon fiber is 0.1 to 10% by weight,
An epoxy resin composition for producing jigs and tools by electric discharge machining, wherein the viscosity at 50 ° C. is in the range of 5 to 200 Pa · s. 2. The healing by electric discharge machining according to claim 1, wherein the average particle size of the metal powder is 100 μm or less.
An epoxy resin composition for tool making . 3. Casting by adding an epoxy resin curing agent,
The cured product according to claim 1 or 2, wherein the cured product has a cure shrinkage of 0.01% or less.
An epoxy resin composition for producing jigs and tools by electric discharge machining . 4. A composition obtained by mixing the epoxy resin composition for jigs and tools according to any one of claims 1 to 3 with an epoxy resin curing agent, casting, curing , and discharging.
Epoxy resin mold obtained by processing .