JPH01202407A - Manufacture of resin mold - Google Patents

Abstract

PURPOSE:To improve electric conductivity of a surface layer by constituting the surface layer provided with excellent strength properties and water resistance, by a method wherein the surface layer is constituted by impregnating thermosetting resin into a metallic fiber and solidifying the same. CONSTITUTION:A resin mold surface layer 3 and intermediate paste layer 4 are laminated and formed to a base mold 2 fixed onto a bottom plate 1a of a core box. A matter obtained by impregnating thermosetting resin such as epoxy resin, polyester resin or urethane resin into a metallic fiber for which, for example, stainless steel is used and solidified is employed for the resin mold surface layer 3. As the metallic fiber is exposed at a position close to the surface of the mold, the surface of the resin mold is reinforced with mechanical strength properties, wear resistance, compression resistance and heat resistance provided for the metallic fiber. Especially heat conductivity of a resin mold surface layer is improved through the inclusion of the metallic fiber and heat distribution can be made uniform. Therefore, a defect which is particular to the thermosetting resin such as weakness to heat is improved and the rupture of the surface layer due to frictional heat at the time of press processing is prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is suitable for manufacturing resin molds that can be used in place of various molds such as press molds, injection molds, or vacuum molds. Regarding the method.

[Conventional technology]

Molding machines such as press molding machines and injection molding machines usually use molds made from various types of mold steel, but the cutting process of these molds is troublesome and they are very expensive. Therefore, as high-mix, low-volume production is progressing these days, the proportion of total mold costs in the total manufacturing price of a product has increased, making it uneconomical, and manufacturing delivery times are long, which has a large impact on product manufacturing. There was a problem.

Therefore, as an alternative to the conventional metal mold, the surface is covered with a thermosetting resin (gel coat), the inside is covered with an intermediate paste layer that is a mixture of resin, metal powder, and glass chop, and the inside The idea was to use a resin mold made of glass fibers covered with a laminate layer made of resin impregnated.

However, with the resin mold having the above structure, the thermosetting resin itself that constitutes the gel coat does not have sufficient mechanical strength, abrasion resistance, and heat resistance, and the glass fiber of the laminate layer does not have sufficient resistance. It does not have abrasion resistance or heat resistance, and the glass fiber does not directly appear on the surface of the mold.
There is a problem that the surface of the mold becomes deformed and worn when used repeatedly, and in addition, the structure between the gel coat and the intermediate paste layer is such that they are bonded when the thermosetting resin becomes gelled or semi-gelled. As a result, the gel coat and intermediate paste layer are not completely integrated structurally, but are merely adhered to each other, and the thermosetting resin shrinks during curing, creating a gap between it and the intermediate paste layer. Due to the manufacturing process, peeling often occurs between the intermediate paste layer and gel coat during use.
Therefore, the number of times the resin mold can be used is extremely small, and at best it can only be used for molding prototypes, and there is a problem that it cannot be used as a regular mold instead of a metal mold.

Therefore, the present applicant applied thermosetting resin to synthetic fibers (aramid fibers) on the surface of the resin mold, as seen in the earlier application of Japanese Patent Application No. 60-86053 (Japanese Unexamined Patent Publication No. 61-244508). By forming a surface layer that is impregnated and solidified, we have developed a resin mold that has excellent surface strength, wear resistance, and heat resistance, and can be used repeatedly as a main mold over a long period of time. Ta.

[Problem to be solved by the invention]

However, even with the resin mold developed by the applicant, there are limits to the strength and abrasion resistance of the surface layer, so there is a problem that it cannot be used repeatedly as a main mold for a long period of time. If epoxy resin, etc., which is relatively heat-resistant and has low thermal conductivity, is used as a thermosetting resin for the surface layer, the frictional heat during pressing will concentrate on a part of the surface layer, causing damage to the surface layer. There was also the problem that the life of the resin mold was shortened by accelerating the process.

Although the above problem can be solved to some extent by mixing metal powder into the thermosetting resin that constitutes the surface layer, it is extremely difficult to uniformly distribute the metal powder in the resin. It was found that it was not possible to increase the amount of metal powder mixed, and therefore, it was not possible to obtain the desired strength and thermal conductivity with this method.

Therefore, the technical problem of the present invention is to construct a surface layer on the surface of a resin mold that has even better strength and wear resistance, and to improve the thermal conductivity of this surface layer so that it can be thermoset. The goal is to overcome the disadvantage of heat-resistant resins.

[Means to solve the problem]

The measures taken in the present invention to solve the above technical problems are as follows.

In manufacturing a resin mold whose surface is covered and reinforced with a surface layer of thermosetting resin by filling a sand core into a core box whose inner surface is coated with thermosetting resin,
The above surface layer is composed of metal fibers impregnated with thermosetting resin and solidified.

However, here, thermosetting resin means condensation resins such as epoxy resin, unsaturated polyester resin, and urethane resin, and sand core means a mixture of silica sand, glass chop, and resin. Furthermore, metal fibers refer to those formed from various metals such as stainless steel, copper, or iron into a cross shape, thread shape, or wave shape (cotton shape).

[Effect]

The above means works as follows.

■ The surface layer that covers the surface of the resin mold is reinforced with metal fibers, so it exhibits even better strength and abrasion resistance than the conventional surface layer that uses synthetic fibers. It protects the resin mold and allows it to be used repeatedly as a main mold over a long period of time.

■ Since the surface layer is composed of metal fibers impregnated with thermosetting resin and solidified, the distribution of metal fibers in the surface layer can be easily made uniform, and therefore the amount of metal fibers used can be increased. It is possible to further improve the strength and abrasion resistance of the surface layer.

■ The thermal conductivity of the surface layer is improved by the metal fibers.

Since the heat distribution can be made uniform, the surface layer will not be locally heated due to frictional heat during press processing, and therefore the surface layer made using thermosetting resin will not be damaged by heat. make it possible to solve problems.

As described above, the above-mentioned technical problem can be solved by the above-mentioned means, and the problems of the conventional technology can be solved.

〔Example〕

Hereinafter, preferred embodiments of the resin mold manufacturing method according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view showing a state in which a resin mold surface M3 and an intermediate paste layer 4 are laminated on a base mold 2 fixed on a bottom hole 1a of a core box generally indicated by reference numeral 1. For the resin mold surface N3, for example, a thermosetting resin (condensation resin) such as epoxy resin, polyester resin, or urethane resin is used on metal fibers made of stainless steel.
A material that has been impregnated with and solidified (gel-in-the-fiber coating) is used.

To explain the structure of the resin-type surface layer 3 in more detail, when the metal fibers used are woven in a cross shape or processed into a wave shape like cotton.

Each surface of the cloth or wave is impregnated with the above-mentioned thermosetting resin solution by applying it using a brush, spatula, etc., or by mechanically spraying, and further, the impregnated cloth or wave is As shown in FIG. 1, the resin mold surface layer 3 is constructed by manually or mechanically pressing the resin mold 2 onto the surface of the base mold 2 and the inner wall surface of the core box 1.

The resin-type surface layer 3 configured in this manner maintains the relative position of the metal fibers as the thermosetting resin solidifies, and exhibits excellent strength, abrasion resistance, and heat resistance as described below. Can be done.

After the resin mold surface M3 has been formed, the intermediate paste layer 4 described above is subsequently laminated on the surface of the surface layer 3 as shown in FIG. A mixture obtained by mixing metal powder and glass chops in a resin solution is applied onto the resin mold surface layer 3 using a brush or spatula, or by spraying with a machine. This intermediate paste layer 4 serves as a medium to integrally bond the resin mold surface layer 3 and the sand core described later, and the resin used is the same as that used for the resin mold surface WI3. The same type of thermosetting resin is used, and the resin of this surface layer 3 is semi-cured (
Continuous forming operations are carried out before tack-free (tack-free).

In FIGS. 2 and 3, reference numeral 5 indicates a sand core that is continuously filled into the space in the core box 1 after the intermediate paste layer 4 is formed. For example, this sand core 5 made by mixing silica sand, glass chop, and a resin solution is filled into the core box 1 by manual or mechanical work. In order to use a thermosetting resin similar to that used in the intermediate paste layer 4, the intermediate paste layer 4 is used as a medium to strengthen the resin, depending on the mutual affinity of these resins and the gelation of each resin. The resin-type surface layer 3 containing metal fibers can be integrally bonded and fixed to the surface of the sand core 5.

Further, in Fig. 2, 6 is a leveling resin layer injected to level the upper surface of the filled sand core 5, and 7 is a presser plate that presses this resin layer 6 to create a horizontal surface. .

After each of the above operations is completed and each resin is solidified, the fur box 1 is removed and released from the base mold 2 as shown in Fig. 3, so that the surface is covered with a resin mold surface layer 3 containing metal fibers. Moreover, this metal fiber is near the surface < (0,0
A resin mold 10 with an exposed area of 1 to 0.510 nm is manufactured.

〔effect〕

Since the method for manufacturing a resin mold according to the present invention is as described above, the resin mold manufactured according to the present invention has a structure in which the metal fibers blended in the resin mold surface layer are exposed near the surface of the mold. The surface of the resin mold is strengthened by the mechanical strength, abrasion resistance, compression resistance, and heat resistance of this metal fiber.
Therefore, it is possible to extremely easily produce a resin mold that is stronger than conventional resin molds in which synthetic fibers are blended into the surface layer of the resin mold, and has durability close to that of molds. In particular, the combination of metal fibers improves the thermal conductivity of the resin mold surface layer and makes the heat distribution uniform, which improves the heat-resistant disadvantage of thermosetting resins.
This has the advantage of preventing damage to the surface layer due to frictional heat during press processing and further extending the life of the resin mold. It is useful for manufacturing various molds such as molds, injection molds, vacuum molds, FRP molds, RIM molds, and casting models.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are cross-sectional views sequentially illustrating the state in which a resin mold is manufactured by implementing the resin mold manufacturing method according to the present invention. 1 is a core box, 2 is a base mold, 3 is a resin mold surface layer containing metal fibers, 4 is an intermediate paste layer, 5 is a sand core, and 10 is a resin mold manufactured according to the present invention. Patent applicant: Resin Machine Mold Co., Ltd. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In manufacturing a resin mold whose surface is covered and reinforced with a surface layer of thermosetting resin by filling a sand core into a core box whose inner surface is coated with thermosetting resin,
A method for producing a resin mold, characterized in that the surface layer is formed by impregnating metal fibers with a thermosetting resin and solidifying the surface layer.