JPH05169472A - Production of model mold and epoxy resin composition - Google Patents

Abstract

PURPOSE:To produce a model mold containing no air bubbles in its surface layer and having uniform wall thickness and good quality accuracy without generating the loss of a material and requiring a correction process. CONSTITUTION:A composition containing an epoxy resin and a curing agent is applied to a synthetic resin film 2 and semicured to obtain a flexible plate- shaped object 4 which is, in turn, demolded and reversed to be brought into close contact with the upper surface of a master model. Subsequently, the synthetic resin film 2 is peeled off to cure the plate-shaped object 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a model type manufacturing method and an epoxy resin composition.

[0002]

2. Description of the Related Art A model type made of a cured epoxy resin (hereinafter referred to as a model type) is homogeneous like a wooden type, with no directionality, inversion, knots, etc., easy to cut and temperature change. It also has small expansion and contraction due to, and has excellent properties as a model type material. The model mold is a method in which putty made of epoxy resin is manually placed on a wooden mold or a plaster mold (hereinafter referred to as a master model) having a desired shape, hardened, and then surface-finished by NC processing or the like. Or putty method) or a method of finishing the surface of a block-shaped epoxy resin cured product by NC processing or the like (hereinafter referred to as a block method).

[0003]

The prior art has the following problems. (A) Putty method In the putty method, an epoxy resin and a curing agent are mixed,
Without putting it, put this putty into a mold like a master model by hand. Therefore, even in the case of a master model having large unevenness, a complicated curved surface, or a deep groove, a mold having a relatively uniform thickness can be obtained in one step, and the amount of epoxy resin used can be small. ..

However, the putty method has the following drawbacks. When mixing the epoxy resin and the curing agent, bubbles are entrained by stirring, and complete defoaming is difficult. For this reason, cavities and bubbles are likely to occur in the mold, and even if precision machining is performed by NC processing, cavities and bubbles are generated on the surface. In order to close this hole, it is necessary to fill the hole with putty and perform NC processing on the filled portion again, which requires a great amount of correction process, which not only deteriorates the quality but also causes the filling portion to be processed. In addition, minute small holes may occur.

Further, since the putty is put up manually, the thickness tends to vary. If the wall thickness varies,
There is variation in the degree of heat generated by curing, and the portion with a large thickness rises in temperature as compared with the portion with a small thickness and cures earlier, thus completing the curing earlier. For this reason, a portion having a large thickness that has been quickly cured pulls a portion having a small thickness that has not been cured, and the quality is deteriorated. In addition, the dimensional accuracy deteriorates due to variations in heat generation temperature.

(B) Block Method In the block method, a liquid epoxy resin is cast to form blocks in advance, and a predetermined number of these blocks are bonded together, and then NC processing is performed. In the block method, the surface portion of the block, in which air bubbles are easily mixed, is removed in advance, so that a correction process after NC processing is not required, but in the case of a mold having large irregularities, a plate-shaped body is used. Since it is necessary to use a block having a large thickness that is bonded together, a large amount of material loss occurs. In addition, in the block method, not only the number of man-hours is required for the bonding work, but also the thickness of the mold cannot be made uniform, and the weight of the mold becomes large.

The present invention solves the above-mentioned problems of the prior art, eliminates the need for a correction process due to the inclusion of bubbles and the like, and does not cause material loss, and a method of manufacturing a model type with a uniform thickness, and It is an object of the present invention to provide an epoxy resin composition extremely suitable for this production method.

[0008]

In order to achieve the above object, in the present invention, a liquid epoxy resin having a viscosity of 2,000 to 20,000 cps at room temperature (23 ° C.) and a liquid curing agent are mixed. Then, it is cast in a flat plate shape, semi-cured to form a flexible plate-like body, and this plate-like body is released, inverted and pressed against a mold having a desired curved surface shape, and brought into close contact, Then, a model mold is manufactured by curing, and as an epoxy resin composition, 100 parts by weight of a liquid epoxy resin having a viscosity at room temperature (23 ° C.) of 2,000 to 20,000 cps and a liquid heat-curable curing agent 5 are used. ~
An epoxy resin composition in which 40 parts by weight and 5 to 40 parts by weight of a greenhouse curing type curing agent are mixed is used.

Next, the present invention will be described more specifically with reference to FIGS. In the present invention, the epoxy resin has a viscosity of 2,000 to 2 at room temperature (23 ° C.).
10,000 cps, preferably 3,000 to 12,000
Use 0 cps. If this viscosity is too high, defoaming will be incomplete and bubbles will tend to remain in the mold,
If this viscosity is too low, the time required for production will be long and the performance of the mold will be likely to deteriorate.

As the heat curing type curing agent, dicyandiamide, boron trifluoride amine complexes, acid anhydrides, aromatic amines, tertiary amine modified products, and as the room temperature curing type curing agent, aliphatic amines, amidoamines , Alicyclic amines and the like can be used, but particularly, when a heat-curable curing agent and a room-temperature-curable curing agent are used in combination, especially when a tertiary amine and an aliphatic amine are used in combination, very preferable results are obtained. You can get Ratio of epoxy resin and curing agent is 100: 1
0 to 100, preferably 100: 50 to 100, and the ratio of the liquid epoxy resin to the heat curing type curing agent and the room temperature curing type curing agent is 100: 5 to 40: 5.
-40, preferably 100: 10-20: 30-40
Is appropriate. The method of mixing the liquid epoxy resin and the curing agent is not particularly limited, and a conventional method can be used. In addition,
At this time, a filler such as iron powder and aluminum powder, liquid polybutadiene, liquid rubber such as liquid polysulfide, and the like can be mixed.

In a square mold 1, a vinyl chloride film, a polyethylene film, a polypropylene film,
A synthetic resin film 2 such as a polyethylene terephthalate film or a nylon film is placed, and an epoxy resin composition (hereinafter referred to as the present composition) 3 containing the above-mentioned epoxy resin and a curing agent is cast on the synthetic resin film 2. The composition 3 has fluidity and its thickness is extremely uniform. The synthetic resin film has a thickness of 200 to 400 μm, and the casting thickness of the composition is 20 to 50 mm, preferably 20 to 30 mm.
Is appropriate.

After casting, the composition is allowed to stand at room temperature to semi-cure the composition and to have flexibility in the form of plate 4.
To get The standing time is 3 to 15 hours at 20 to 25 ° C. The time required for semi-curing can be shortened by heating the composition to about 30 ° C.

The viscosity of the present composition is sufficiently low that the air bubbles trapped in the composition rise before reaching the semi-cured state of the composition and reach the upper part of the plate to be defoamed. Although some of the bubbles may remain above the plate-like body 4, no bubbles remain below the plate-like body 4.

When the viscosity of the composition of the present invention is sufficiently increased to become a dough-like shape, the plate-like body 4 is released from the mold 1 and inverted while the synthetic resin film 2 is in close contact with the plate-like body 4. Place it on the upper surface of the master model 5 and lightly press it with your hand to bring it into close contact with the surface of the master model 5. The plate-like body 4 has sufficient flexibility, and it is brought into close contact with the surface of the master model 5 with high precision by simply pressing it lightly.

Then, the synthetic resin film 2 is peeled off by hand,
Desirably, it is further cured at room temperature and then heated to be cured. Since the viscosity of the plate-like body is sufficiently large at the time of releasing, the composition does not flow during this process and the thickness of the plate-like body does not change, and a model die 6 having a uniform thickness is obtained. Be done. Then, the model die 6 is precisely finished by NC processing. Since the surface portion of the mold manufactured by the above method is formed in the lower part of the plate-shaped body obtained by casting, no bubbles remain on the surface and the correction step is unnecessary.

[0016]

Function: Viscosity at room temperature is 2,000 to 20,000
A liquid epoxy resin of cps and a liquid curing agent are mixed, cast into a flat plate, semi-cured to form a flexible plate, and the plate is released and turned upside down. Then, a model die having a uniform thickness and a light weight is manufactured by pressing, closely adhering to a die having a desired curved surface shape, and then curing the die without a correction process and material loss. Further, 100 parts by weight of a liquid epoxy resin having a viscosity at room temperature of 2,000 to 20,000 cps and 5 to 4 heat-curable curing agents are added.
By using an epoxy resin composition in which 0 parts by weight and 5 to 40 parts by weight of a room temperature curable curing agent are mixed, the above effect can be further enhanced.

[0017]

EXAMPLE 100 parts by weight of a liquid epoxy resin having a viscosity of 5,400 cps, 20 parts by weight of a modified tertiary amine and 16 parts by weight of an aliphatic amine were mixed by stirring, and the resulting epoxy resin composition was chlorinated to 300 μm. Into a rectangular mold whose bottom surface was covered with a vinyl film, a mold having a thickness of 30 mm was cast and left for 15 hours to be semi-cured to produce a sticky plate-shaped body. This plate-like body is released from the mold together with the film, inverted and placed on the upper surface of the master model, lightly pressed by the hand to make it adhere to the upper surface of the master model, the film is peeled off by hand, and left at room temperature for about 15 hours, The temperature was raised to 80 ° C. for about 4 hours and heat-cured at 80 ° C. for 2 hours to obtain a model mold having a uniform thickness and having no bubbles on the surface, and a correction process after NC processing was unnecessary.

[0018]

EFFECTS OF THE INVENTION There is no air bubble on the surface, no correction process is required, and a model die having uniform thickness and good quality and accuracy can be manufactured without material loss.

[0019]

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a manufacturing method of the present invention.

FIG. 2 is a cross-sectional view showing the manufacturing method of the present invention.

FIG. 3 is a perspective view showing a model mold of the present invention.

[Explanation of symbols]

 1 type 2 synthetic resin film 3 epoxy resin composition 4 plate body 5 master model 6 model type

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Claims (4)

[Claims] 1. The viscosity at room temperature is 2,000 to 20,
A liquid epoxy resin of 000 cps and a curing agent are mixed, cast into a flat plate, and semi-cured to form a flexible plate-like body. The plate-like body is released from the mold and inverted upside down. A method for producing a model mold, which comprises pressing and closely contacting a mold having a desired curved surface shape, and then heating and curing. 2. The method for producing a model die according to claim 1, wherein the curing agent includes a heat-curable curing agent and a room-temperature-curable curing agent. 3. The method for producing a model mold according to claim 2, wherein the weight ratio of the epoxy resin, the heat curing type curing agent and the room temperature curing type curing agent is 100: 5 to 40: 5 to 40. 4. The viscosity at room temperature is 2,000 to 20,
100 parts by weight of liquid epoxy resin of 000 cps, 5 to 40 parts by weight of heat curing type curing agent and 5 to 5 parts of room temperature curing type curing agent
An epoxy resin composition obtained by mixing 40 parts by weight.