JPS6137406A - Multi-color casting method - Google Patents

Abstract

PURPOSE:To make it possible to obtain easily a molding article having different colors and structures partly, by injecting a first liquid resin into an injection mold, curing or hardening it, setting it as insert in an injection mold of a resilient material, injecting a second liquid resin good in adhesion to the first fluid resin, and curing or hardening it. CONSTITUTION:The liquid resins used includes resins that are liquid at normal temperatures, as well as resins that become liquid when heated, and, in particular, urethane resins, epoxy resins and polyester resins that are liquid at normal temperatures are preferred. The injection of the first liquid resin is effected in the usual injection method. The thus obtained item is set as an insert in a second injection mold. Therefore the second injection mold should be made of a resilient material such as silicone rubbers. Thereafter, the second liquid resin is injected. The second liquid resin should be a resin good in adhesion to the first resin, and it is preferred that the surface area where the joining is effected is large to increase the bonding strength between the first injected resin and the second injected resin.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a multi-color casting method suitable for high-mix, low-volume production. This invention relates to a multicolor casting method suitable for molding molded products of different colors or molded products with partially different structures.

[Prior art]

Traditionally, to obtain multicolored cast products, two molded parts were usually molded on the sides.
Methods such as joining two or more parts together or coating them with a different color of paint after molding were used, but these involved many steps and required a great deal of effort and time to obtain the finished product. .

[Purpose of the invention]

An object of the present invention is to provide a casting method that can easily mold two-tone molded products made of the same type of resin with different colors or molded products with partially different structures.

[Structure of the invention]

In the present invention, a first liquid resin is injected into a casting mold, cured or solidified, and then set as an insert in a casting mold made of an elastic material such as silicone rubber. This is a multicolor casting method characterized by having a step of injecting a second liquid resin having good adhesiveness with the liquid resin and curing or solidifying the liquid resin.

The liquid resin used in the present invention includes not only those that are liquid at room temperature but also those that become liquid when heated. The type of such resin is not particularly limited, but thermosetting resins 4, particularly urethane resins, engineered boxy resins, and polyester resins, which are liquid at room temperature, are preferred. The second liquid resin needs to have good adhesion to the first resin. Specifically, the same resin or the same type of resin is preferable. The same resin refers to cases where the resin components are exactly the same, but also includes cases where the colors are different, the fillers added are different, etc. The same type of resin means, for example, a case where the resin or curing agent is different within the range of epoxy resin.

The first liquid resin is cast by a conventional casting method. The obtained molded product is set as an insert in a second casting mold. For this reason, the second casting mold is made of an elastic material such as silicone rubber so that it can absorb minute variations in the shape and size of the first casting molded product to be set as an insert. . Silicone rubber is most preferred in terms of ease of moldability and heat resistance.

After that, the liquid resin of cylinder 2 is injected. As mentioned above, the second liquid resin is one that has good adhesion to the first resin, but in order to increase the adhesive strength between the two, it is preferable to increase the surface area of the joint. It is preferable that the joint portion of the first molded product (insert) is formed into a stepped shape, and that it is further subjected to a roughening treatment.

In addition, before setting the primary molded product in the second casting mold,
By covering the vicinity of the joint of the outer surface of the finished product with tape or the like, it is possible to prevent the outer surface of the finished product from being soiled by the 92-order liquid resin.

〔Effect of the invention〕

As described above, the casting method of the present invention has the advantage of easily producing molded products with partially different colors and partially different structures. It is suitable for manufacturing many types of keyboards with different color tones for push buttons, and keyboards for personal computers, word processors, etc. with partially different key positions.

Claims (1)

[Claims] After the first liquid resin is injected into the casting mold and cured or solidified, the resin is set as an insert in a casting mold made of an elastic material such as silicone rubber, and is bonded to the first liquid resin. A multicolor casting method comprising the step of injecting a second liquid resin with good properties and curing or solidifying it.