JPH06135B2 - Gypsum mold for denture base molding - Google Patents

Description

TECHNICAL FIELD The present invention relates to a plaster mold for efficiently molding a denture base having a smooth surface.

[Prior Art and Problems Thereof] A gypsum mold is generally used as a mold for molding a denture. A conventional denture base made of a commonly used methyl methacrylate polymer has a molding temperature of 100 ° C. or lower. Therefore, sodium alginate, which has relatively low heat resistance, has been used as a material for separating the gypsum mold and the denture base without problems. However, in the case of a material having a high molding temperature such as a polysulfone denture base, there is no suitable mold release material, which is a problem.

In JP-A-59-189838, a heat-resistant fluororesin is applied to the surface of a gypsum mold, dried at 80 to 90 ° C. for 10 minutes, and then heated at a rate of 10 ° C./minute to give a temperature of 380 to 380. Three
It is disclosed that a denture base having a smooth surface is obtained by forming a fluororesin coating on the surface of a plaster mold by firing at a temperature of 90 ° C. for 10 minutes. However, this method requires a temperature raising operation, so that the equipment is extremely expensive. Further, since the baking temperature of the fluororesin is as high as 380 to 390 ° C., the strength of the gypsum mold is lowered. Further, if the firing temperature is lowered in order to keep the gypsum strength high, there is a problem such that the mold and the denture base are separated from each other poorly.

[Means for Solving Problems] The present invention relates to a method for efficiently forming a denture base having a smooth surface.

That is, the present invention relates to a plaster mold for denture base molding, which has a silicon resin coating and a heat resistant resin coating on the surface in this order.

When shaping a denture base using a plaster mold, the molding temperature is 1
When the temperature is higher than 00 ° C, especially higher than 180 ° C, the surface of the plaster mold is roughened. Therefore, the surface of the gypsum mold is provided with a silicon resin film and a heat-resistant film as a release material to prevent the surface from roughening.

Examples of the silicone resin include organopolysiloxane having a silicon-oxygen bond as a skeleton and silicone oil having a linear structure. These mold release materials are directly applied to the plaster mold surface.

Examples of the heat resistant resin include resins having excellent heat resistance such as polyimide and fluororesin.

In the case of forming a polyimide coating, water in the gypsum is substantially removed, then a varnish which is a polyimide precursor is applied and further heated to form a polyimide coating.

When forming a fluororesin film, a suspension in which a fluororesin and a binder are dispersed is applied and dried. If necessary, a baking operation is performed.

As the heat resistant resin, polyphenyl sulfide, thermosetting resin, or the like may be used in addition to the above.

On the surface of the heat-resistant resin coating formed as described above, after forming a coating by applying a mold release material, the gypsum mold temperature is raised to the temperature required for denture base molding, and a softened denture base molding resin is obtained. Fill into a plaster mold.

The present invention will be described below with reference to examples.

Example 1 A gypsum mold formed into a mold is dried at 200 ° C. for 1 hour. Apply the polyamic acid varnish on the plaster mold surface with a brush and apply 200
Dry at 30 ° C. for 30 minutes to form a polyimide resin film. Silicone oil KF-96 (manufactured by Shin-Etsu Silicone Co., Ltd.) was applied on this polyimide resin film, and then a polysulfone plate was placed on the plaster mold and heated at 380 ° C. for 3 minutes to be softened. After the resin softened, the upper and lower gypsum molds were combined and compression molding was performed to produce a denture base. The plaster mold was cooled and the denture base was taken out. The plaster mold and the molded denture base could be separated very easily, and the surface of the taken denture base was smooth and glossy.

Example 2 A fluororubber-containing liquid Daier latex GLS-213 (manufactured by Daikin Chemical Industries, Ltd.) was applied to the surface of a plaster mold that had been molded into a mold, and dried at room temperature, and then the silicone resin SR-24.
02 (manufactured by Toray Silicone Co., Ltd.) was applied. Plaster mold 2
The denture base was molded in the same manner as in Example 1 by heating at 00 ° C. for 1.5 hours. As a result, it was extremely easy to separate the plaster mold and the denture base, and the surface of the taken out denture base was smooth and glossy.

Comparative Example 1 Silicone oil KF-9 was applied on the surface of a plaster mold formed in a mold.
After applying 6, the denture base was molded in the same manner as in Example 1 except that the plaster mold was heated at 200 ° C. for 1.5 hours. As a result, plaster adhered to the formed denture base and separation was difficult.
The surface of the denture base was whitened and no gloss was observed.

Comparative Example 2 A denture base was molded in the same manner as in Example 2 except that the silicone resin was not applied. As a result, the fluororubber adhered to the surface of the denture base, and it took a long time to remove it. Also,
Although no whitening phenomenon was observed on the denture base surface, no gloss was observed at all.

Claims (1)

[Claims] 1. A plaster mold for molding a denture base, in which a silicon resin coating and a heat resistant resin coating are provided in this order on the surface.