JPH0586891B2 - - Google Patents

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 mold steels, but the cutting process of molds is troublesome and they are very expensive. Therefore, as high-mix, low-volume production is progressing, mold costs account for a high proportion of the total manufacturing price of a product, 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, we covered the surface with thermosetting resin (gel coat).
The inside is covered with an intermediate paste layer, which is a mixture of resin, metal powder, glass chips, etc.
Furthermore, it has been considered to use a resin mold whose inside is covered with a laminate layer made of glass fiber impregnated with resin.

However, in 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.
The glass fibers in the laminate layer also do not have sufficient abrasion and heat resistance, and because the glass fibers do not come directly onto the surface of the mold, repeated use will cause the surface of the mold to deform and wear out. In addition, the gel coat and intermediate paste layer are structured so that they are bonded together when the thermosetting resin is gelled or semi-gelled, so the gel coat and intermediate paste layer are structurally perfect. The two are simply glued together without being integrated, and since the thermosetting resin shrinks during curing and creates a gap between the intermediate paste layer and the gel coat, the intermediate paste layer and gel coat may be separated 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 in place of a metal mold.

Therefore, the present applicant has filed the previous Japanese Patent Application No. 60-86053 (Japanese Unexamined Patent Publication No. 61-244508),
As seen in each application of No. 28342, reinforcing fibers such as synthetic fibers such as aramid fibers, and metal fibers formed from various metals into a cross shape, thread shape, or wave shape are used on the surface of the resin mold. By impregnating and solidifying thermosetting resin with a thermosetting resin to form a surface layer, and by bonding these reinforcing fibers with double-sided adhesive tape, the surface can be given excellent strength and durability. We have developed a resin mold that has wear resistance and heat resistance and can be used repeatedly as a main mold for a long period of time.

[Problem to be solved by the invention]

However, in the case of reinforcing fibers with strength such as the synthetic fibers and metal fibers mentioned above, each fiber has an extremely strong repulsive force.
When impregnated with thermosetting resin and solidified, or bonded with double-sided adhesive tape, many fibers will cause a bridging phenomenon on the surface of the surface layer and protrude like whiskers. If molding is carried out with the molded product as it is, it will leave scratches on the surface of the molded product, resulting in the problem that surface treatment requires a great deal of time and effort.

In addition, as mentioned above, in the case of resin molds in which various reinforcing fibers are directly exposed on the surface, when used in press molds, there is a problem that slipperiness during pressing becomes poor due to the frictional resistance of the fibers. Furthermore, when this resin mold was used in an injection mold or a vacuum mold, there was a problem in that the fiber texture was transferred to the surface of the molded product.

Therefore, the technical problem of the present invention is that the reinforcing fibers do not protrude like whiskers on the surface layer, and that the surface can be molded to be smooth and exhibit excellent sliding properties. The object of the present invention is to provide a method for manufacturing a resin mold that is devised so that the texture of the fibers is not transferred.

[Means to solve the problem]

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

Reinforcing fibers such as synthetic fibers or metal fibers are stretched over the surface of the base mold coated with a release agent, and the surface is reinforced with a reinforcing fiber layer by filling this base mold with sand core or cement. In the method of manufacturing a resin mold, the surface of the reinforcing fiber layer is impregnated with a fast-curing adhesive to form the surface of the resin mold.

However, the term "sand core" as used herein means a mixture of silica sand, glass chips, and resin. Furthermore, synthetic fibers refer to carbon fibers, aramid fibers, glass fibers, etc., and metal fibers refer to various metals such as stainless steel, copper, or iron in the form of crosses, threads, or waves. (cotton-like).

[Effect]

The above means works as follows.

The surface layer that covers the surface of the resin mold is reinforced with a reinforcing fiber layer such as synthetic fibers or metal fibers, so this fiber layer exhibits excellent strength and abrasion resistance, making the resin mold more durable. It protects the surface and allows the resin mold to be used repeatedly as a main mold over a long period of time.

The fast-curing adhesive (instant adhesive) impregnated on the surface of the reinforcing fiber layer permeates and diffuses between each fiber and flows, impregnating each fiber itself, which closes the fiber weave. In addition, the adhesive strength of the fast-curing adhesive prevents bridging of each fiber, making it possible to form a smooth surface of the resin mold to improve slippage during press molding, and to make the surface smoother. To manufacture a clean molded product without ridge marks or texture transfer marks.

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 shows a reinforcing fiber layer 3 impregnated with a fast-curing adhesive and an intermediate paste layer 4 on a base mold 2 fixed on a bottom plate 1a of a mold, generally indicated by reference numeral 1. It is a cross-sectional view showing a laminated state, and the reinforcing fiber layer 3 is made of synthetic fibers such as aramid fibers, or metal fibers made of stainless steel or the like.
In order to impregnate the surface of the base mold 2 with a quick-curing adhesive (not shown), the fast-curing adhesive is applied to the surface of the base mold 2 coated with a release agent (not shown), and the applied adhesive is The reinforcing fibers are pasted on top of the reinforcing fibers, or the quick-curing adhesive described above is applied to the surface of the reinforcing fibers, and then the reinforcing fibers are pasted onto the base mold 2 coated with a release agent. Yes, the selection is optional.

In addition, instant adhesives of various compositions such as emulsion type, prepolymer type, heat-melting type, and pressure-sensitive type can be used as fast-curing adhesives, but for the experiment, we used a product manufactured by Konishi Co., Ltd. I used the famous Bond quiz set.

As described above, the reinforcing fiber layer 3 impregnated with the fast-curing adhesive has fluidity, which is a characteristic of the fast-curing adhesive.
The actions of leakage, penetration, diffusion, adsorption, and solidification act strongly and quickly between molecules, preventing the reinforcing fibers from rising due to the repulsive force, and allowing the adhesive to close the fiber weave. Because of this, it is possible to form a smooth surface and exhibit excellent strength, abrasion resistance, and heat resistance as described below.

After the above-mentioned reinforcing fiber layer 3 has been formed, the above-mentioned intermediate paste layer 4 is subsequently laminated on the surface of this fiber layer 3 as shown in FIG. What is obtained by mixing metal powder and glass chips in a resin solution,
This intermediate paste layer 4, which is formed by applying it on the reinforcing fiber layer 3 using a brush or spatula or by spraying it with a spraying machine, is made by combining the reinforcing fiber layer 3 with sand core or cement, which will be described later. The resin used here is a condensation resin such as epoxy resin, unsaturated polyester resin, or urethane resin, which is impregnated into the fiber layer 3. The fast-curing adhesive is formed continuously before curing.

In FIGS. 2 and 3, reference numeral 5 indicates a sand core that is continuously filled into the space in the mold 1 after the intermediate paste layer 4 is formed. For example, the sand core 5 made by mixing silica sand, glass chips, and a resin solution is filled into the mold 1 by manual or mechanical work. In order to use thermosetting resins similar to those used in the above, a fast-curing adhesive was applied using the intermediate paste layer 4 as a medium, depending on the mutual affinity of these resins and the gelation of each resin. The impregnated reinforcing fibers 3 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 has been completed and each resin and adhesive has solidified, remove the mold 1 and use the base mold 2 as shown in Figure 3.
The reinforcing fiber layer 3 whose surface is impregnated with a fast-curing adhesive and formed smoothly by being released from the mold
A resin mold 10 covered with
is manufactured.

It is also possible to use cement instead of the sand core 5 described above, and it is also possible to use cement for reinforcement by directly impregnating the surface of the sand core 5 or cement with a fast-curing adhesive without forming the intermediate paste layer 4. It is also possible to form the fiber layer 3, and these selections are arbitrary.

〔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 synthetic fibers or metal fibers constituting the reinforcing fiber layer near the surface of the mold. When exposed, the surface of the resin mold is strengthened by the mechanical strength, abrasion resistance, compression resistance, and heat resistance of these fibers, resulting in a resin mold with durability close to that of conventional molds. In the present invention, the reinforcing fiber layer can be impregnated with a fast-curing adhesive and its surface can be molded to have a smooth surface, resulting in excellent sliding properties. It is possible to produce beautiful molded products with no ridge marks or texture marks on the surface, and it is simple in structure and easy to implement, and it is suitable for press molding or injection molding. It is useful for manufacturing various molds such as molds, vacuum molds, FRP molds, and RIM molds, or casting models.

[Brief explanation of drawings]

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 mold, 2 is a base mold, 3 is a reinforcing fiber layer impregnated with a fast-curing adhesive, 4 is an intermediate paste layer,
5 is a sand core or cement, and 10 is a resin mold manufactured according to the present invention.

Claims (1)

[Claims] 1. Reinforcing fibers such as synthetic fibers or metal fibers are stretched on the surface of the base mold coated with a mold release agent, and the surface is reinforced with the reinforcing fiber layer by filling this base mold with sand core or cement. A method for manufacturing a resin mold, characterized in that the surface of the reinforcing fiber layer is impregnated with a fast-curing adhesive to form the surface of the resin mold.