JPS6399859A - Mold - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mold, particularly a mold used for molding dental materials, bones, joints, and other artificial materials made of calcium phosphate crystallized glass. It is something.

[Prior Art] In recent years, various artificial materials have been proposed for dental materials, bones, joints, etc., and some of them are being put into practical use.

Among these artificial materials, calcium phosphate materials are
Because it is the same or similar to the components of living teeth and bones,
It has the advantage of being a preferred material with little rejection from living organisms. Among these materials, calcium phosphate-based crystallized glass is expected to be used as a dental material because it has excellent moldability, and in particular, its physical properties closely resemble those of natural teeth.

Conventionally, such a material has been obtained by casting a calcium phosphate-based material into a magnesium phosphate-based mold material or a silicate-based mold material, followed by molding and crystallization.

[Problems to be Solved by the Invention] However, in all of these methods, fine cracks or racks occur on the surface of the mold material, and the strength of the mold material is insufficient, so that the shape may partially collapse due to the inflow of glass during molding. This has the drawback that protrusions, cracks, etc. occur on the surface of the obtained glass molded product, and the one-dimensional accuracy is extremely unstable.

[Means for Solving the Problems] The inventor of the present invention aims to eliminate the drawbacks of conventional methods and to find a mold capable of molding a molded product with good dimensional accuracy without producing fine racks on the surface of the molded product. As a result of various studies and examinations aimed at this purpose, it has been found that the above object can be achieved by applying a specific treatment to the vicinity of the molding surface of the mold. Thus, the present invention provides a mold in which #a fibrous material having heat resistance exists from the molding surface of the mold to a depth of at least 10 mm, and a molded product from the molding surface of the same type by using boron nitride in combination. The object of the present invention is to provide a molding die that can easily give 'A#.

In the present invention, the mold base material for making the RH-like substance exist is not particularly limited, and for example, magnesium phosphate, silicate, alumina, aluminum phosphate, zirconia, etc. are appropriately used. It is possible.

The properties of the fibrous material include a diameter of 0.1 to 10 g, l
It is appropriate to adopt a length of 10 to 500 tL. If the diameter is less than 0°lJL, the expected effect will not be fully exhibited, and if it exceeds the above range, the smoothness of the molding surface may be impaired, both of which are undesirable. In addition, if the length is less than 10μ, the expected effect will not be fully exhibited, and if it exceeds the above range, the smoothness of the molding surface of the mold may be impaired, so both are preferred. do not have.

Among these ranges, it is particularly preferable to adopt a diameter of 0.2 to 2 mm and a length of 20 to 200 mm, since the initial purpose can be sufficiently achieved.

Also, such fibers are at least 1111 from the surface of the mold.
It is necessary to make it exist up to the depth of st.

If the depth is less than 101L, it is not appropriate because the initial effect cannot be obtained. When making an actual mold, it is practical to mix m-mole with the raw material for the mold base material so that the fibers are present throughout the entire mold, but essentially the fibers are removed from the surface of the mold to about 50μ. If it exists, the initial purpose can be achieved sufficiently and stably. The amount of fibers to be present in the mold is based on the total amount of the mold base material and the amount of fibers up to the depth at which the fibers are present.
It is appropriate to employ 0.5 to 30% by weight. If the amount is less than the above range, the initial purpose can be sufficiently achieved; conversely, if it exceeds the above range, the smoothness of the molded surface may be impaired, so both are unfavorable. It is particularly preferable to use 1 to 10% by weight, since the initial objective can be sufficiently achieved and the smoothness of the surface of the molded article will not be impaired.

The fibrous material used in the present invention is required to be heat resistant because the object to be molded is initially melted, and specifically, if it is stable at high temperatures of 800°C or higher, Without limitation, such fibers include, for example, silicon carbide, silicon nitride, boron carbide, asbestos, alumina, rock wool,
Examples include silica. Thus, the molded product molded using the mold according to the present invention has a smooth surface, no protrusions or cracks, and has high dimensional accuracy, but this alone has some drawbacks in Ill moldability. In particular, when the object to be molded is calcium phosphate glass, there is a tendency for the mold and glass to partially react, making it difficult to release from the mold.

The inventor conducted studies to improve this point, and found that
It has been found that the presence of boron nitride on the surface of the mold improves mold release properties. The boron nitride may be present to a depth of at least 10 μm from the surface of the mold, similar to the aforementioned fibrous material.

The amount of boron nitride and male substance used is 10 to 80% of the total amount of boron nitride and the mold base material in which they are present.
It is appropriate to employ 0.5 to 30% by weight of the male substance.

If the amount of boron nitride used is less than the above range, a sufficient mold release effect cannot be expected; on the other hand, if it exceeds the above range, the strength of the mold will decrease and fibrous substances may be present. None of these are desirable because they may lose their meaning.

Among these ranges, it is particularly preferable to adopt boron nitride in an amount of 30 to 80% by weight and fibrous material in an amount of 1 to 10% by weight, as the surface smoothness of the molded product is good and the moldability is also sufficient. In fact, as a means for obtaining a mold according to the present invention, for example, a predetermined amount of the above-mentioned H&male substance or this and boron nitride is mixed into a mold base material in advance, and the mixture is hardened on the master surface of the mold to form a mold. A method of applying the above-mentioned fibrous material or a base material mixed with boron nitride to the surface of a mold prepared in advance, and applying the fibrous material or a base material mixed with boron nitride to the surface of the original mold surface (wax pattern in the case of the lost wax method). , after forming a layer containing the fibrous material or the boron nitride by coating or dipping the substrate containing the fibrous material or the boron nitride;

A method of creating a mold may also be adopted.

Although various materials can be used for molding using the mold according to the present invention, calcium phosphate glass, which is useful as a biomaterial, is particularly suitable. Its composition is, for example, Ca041~48.5 mol%, P2O558,5~
50 mol%, Al2O30.5 to 5 mol%, and the atomic ratio represented by Ga/P is 0.35 to 0.7, preferably 0.35 to 0.48.

Further, as a means for molding such a calcium phosphate glass using the mold according to the present invention, for example, commonly used means such as the lost wax method or press molding can be appropriately employed. Also, the glass thus formed can be further crystallized, in which case it can be crystallized, e.g.
A method such as keeping the material in an electric furnace maintained at 0° C. for about 2 hours is employed.

[Examples] Example 1 A sprue wire was attached to a wax pattern in the shape of a tooth crown, and set in a rubber cone. and diameter 2-4
P, 20 parts of powder of phosphate-based investment material (Blue Best, manufactured by Tokuyama Soda Co., Ltd.) and 40 parts of its special solution are added to 1 part of asbestos with a length of about 100 reeds to obtain a slurry, and this is used to form the wax pattern. A mold surface layer having a thickness of about 0.2+u+ was formed. The whole was placed in a metal ring and buried with a phosphate-based investment material (Blue Best, manufactured by Tokuyama Soda).Then, after drying, the wax pattern was burned off by heating to 700°C to create a dental crown. A lost wax mold was obtained.

On the other hand, Ca024% by weight, Al2O31% by weight, 220
A 575% by weight composition was melted at 1250°C to obtain a glass melt, which was centrifugally cast into the lost wax mold and kept at 680°C for 3 hours to effect crystallization.

Next, the mold was broken and the molded body was taken out, and the sprue wire was cut to obtain a dental crown made of calcium phosphate crystallized glass. Although the obtained tooth crown did not have a glossy surface, no protrusions or cracks were observed, and a glossy surface was obtained by light polishing. The dimensional change of this tooth crown with the wax pattern was 50 μ or less. Example 2 2 parts of silicon carbide whiskers with a diameter of 0.5 to 2 μ and a length of about 20 to 100 μm were mixed with 10 parts of boron nitride powder and ethyl silicate. Binder (HAS-8 manufactured by Colcoat) 15
A homogeneous slurry was obtained by mixing 1 part with 1 part of wax, and this was applied onto the wax turn prepared in the same manner as in Example 1 to form a surface layer of the mold material having a thickness of about 0.2 parts. Example 1
A dental crown made of calcium phosphate crystallized glass was obtained in the same manner as above.

The surface of the resulting tooth crown was very smooth and shiny, and no barrier protrusions were present. or.

Claims (1)

[Scope of Claims] 1. A mold for molding, characterized in that a fibrous material having heat resistance is present to a depth of at least 10 μm from the molding surface of the mold. 2. The fibrous substance has a diameter of 0.1 to 10 μm and a length of 10 to 5 μm.
00μ, the mold according to claim (1). 3. A mold for molding, characterized in that a fibrous substance having heat resistance and boron nitride are present to a depth of at least 10 μm from the molding surface of the mold. 4. The amount of fibrous substances and boron nitride present is 0.5 to 30% of the total amount of these and the mold base material in which they exist.
Claim (3) % by weight, 10-80% by weight
mold for molding. 5. The fibrous substance has a diameter of 0.1 to 10 μm and a length of 10 to 5 μm.
00μ, the mold according to claim (3) or (4).