JPS59103715A - Manufacture for rolling-over mold - Google Patents

Abstract

PURPOSE:To produce a rolling-over mold which is filled finely with metal and is excellent in thermal conductivity by removing an original pattern after the thermosetting resin composition containing granular metal powder poured from the upper side of the original pattern arranged in a frame, is cured. CONSTITUTION:To 100pts.wt. bisphenol A type epoxy resin of about 190g/equiv. by epoxy equivalent, 83pts.wt. acid anhydrous curing agent and 0.1pts.wt. of bimethyl tetraethyl imidazole are added, and mixed at 60 deg.C heating, whereby thermosetting resin composition is obtained. Into 100pts.wt. of this resin composition 1,100pts.wt. granular iron powder with 74-160mum particle diameter preheated at 60 deg.C, is mixed, whereby the thermosetting resin composition for casting may be prepared. This resin composition is cast in a frame 1 from the upper side of an original pattern 2, and vibration is given at 60 deg.C. After 10min since casting, the resin composition is cast again and cured at 100 deg.C for 10hr. Then the rolling-over mold is obtained by curing at 160 deg.C for 10hr after mold release.

Description

[Detailed description of the invention] The present invention relates to an inversion type manufacturing method.

Conventionally, a method is known in which a thermosetting resin composition is mixed with metal powder and then cured to obtain an inverted mold of the original mold. In the case of this method, since the metal powder is generally non-spherical, it is extremely prone to settling in the thermosetting resin composition. Therefore, any shaping method such as the hand lay-ag method or the casting method is selected. There were some advantages.

However, this method has a disadvantage in that it is not possible to obtain a cured resin product densely filled with counter-pressure metal powder because the trapped metal powder is difficult to settle as described above.

Usually, molds for resin molding are required to have high thermal conductivity, but from this point of view, the conventional inverted molds made of thermosetting resin compositions containing metal powder were insufficient. . In other words, the thermal conductivity of metals is 190 Kcal/m-h-'C for aluminum, and 35-5 for iron.
2 Kcal/m-h-°C, whereas synthetic resin 1, for example, polyester resin, has a concentration of 0.2 to 0.4 Kcal/m, h
-℃ + epoxy resin: 0,: 3 to 1.0 Kcal/m
This is because the temperature is only about -h-°C.

The present invention has been made to overcome the above-mentioned drawbacks, and its purpose is to provide an inverted type with good thermal conductivity, in which a synthetic resin is densely filled with metal.

The present invention relates to an inverted mold manufacturing method in which a thermosetting resin composition containing spherical metal powder is cast from above a master mold placed in a frame, cured, and then the master mold is removed.

The material of the spherical metal powder in the present invention is not particularly limited, but may include iron, aluminum, and copper.

Lead, nickel, etc. and alloys thereof are used, and it is desirable that the shape be close to a true sphere, but it is preferably small because it easily settles in the thermosetting resin composition, and more preferably smaller than 0.5 m. More preferred.

In addition, the thermosetting resin composition used in the present invention includes a polyester resin, epoxy resin, urethane resin, etc. containing a curing agent, a coloring agent, an additive, an antifoaming agent, etc., but it is not necessary to limit it to the above. do not have.

Further, the prototype of the present invention is made of a material such as wood, plaster, etc., but there is no limitation to this material. However, it is preferable that the surface is subjected to mold release treatment.

The size of the inverted mold is determined by the frame, which surrounds the original mold and is cast into the mold. However, by placing pipes or finned pipes in the frame in advance during casting, it is possible to An inverted mold with a pipe can be formed.

The casting method in the present invention is not particularly limited.

In order to sufficiently settle and densely fill the spherical metal powder, it is preferable to lower the viscosity of the resin composition and to cure it slowly. It is also desirable to perform casting while applying vibration within a range where the master mold, frame, etc. do not move, and it is also possible to divide the number of injections into multiple times or, depending on the case, to add only the metal powder after casting. In addition, it is preferable that after the original mold is demolded, the material is further post-cured to be completely cured.

The inverted mold in the present invention refers to a mold corresponding to the original mold.

The present invention will be explained below with reference to Examples.

Example 1 Bisphenol Am with an epoxy equivalent of about 190 y-/equivalent
-c-boxy resin 100fE quantity part ICHN-5500 (
83 parts by weight of acid anhydride curing agent 2 (trade name, manufactured by Hitachi Chemical Co., Ltd.) and 0.1 part by weight of 2-methyl-4-ethylimidazole were added, and the mixture was heated to 60°C and mixed to obtain a thermosetting resin composition. Next, 1 ooat amount of this thermosetting resin composition was preheated to 60°C, and ASR, V-
10 (Product name of spherical iron powder 9 manufactured by Nippon Iron Powder Co., Ltd.) 1100
After mixing the heavy sliding part and stirring uniformly, 60℃, pressure 10 mmH
A degassing treatment was carried out for 5 minutes under g for 5 minutes to obtain a thermosetting resin composition for casting. This composition was injected into the frame 1 shown in FIG. 1 from above the master mold 2, and was heated to 500
After 10 minutes of applying vibrations with an amplitude of M, casting was performed again, and after another 20 minutes, only the above-mentioned iron powder was further supplied until it appeared on the surface of the casting. After curing at 60° C. for 5 hours, 80° C. for 3 hours, and 100° C. for 10 hours, the mold was demolded and then post-cured at 160° C. for 10 hours to obtain an inverted mold.

Comparative Example 1 After mixing 100 iJ4j parts of rum powder, a thermosetting resin composition for casting was prepared under the same conditions as in Example 1 except for the degassing time of 20 minutes, and an inverted mold was further molded by the method of Example 1. Obtained.

Next, the characteristics of the inversion type according to Example 1 and Comparative Example 1 are compared as shown in Table 1.

Table 1 It is clear from the results in Table 1 that in the case of the inverted mold according to Example 1, a dense layer is formed in the mold by the 9-spherical iron powder, so that the thermal conductivity and hardness decrease.

The coefficient of linear expansion is superior to that of the inverted type comparative example.

According to the present invention, since a dense layer is formed by casting containing spherical metal powder, it is possible to form an inverted mold with good properties such as thermal conductivity, hardness, and coefficient of linear expansion.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a frame in which a prototype is placed inside according to an embodiment of the present invention. Explanation of symbols

Claims (1)

[Claims] 1. An inverted mold manufacturing method, which is characterized in that a thermosetting resin composition containing spherical metal powder is cast from above a master mold placed in a frame, cured, and then the master mold is removed.