Yoshino Gypsum Co., Ltd.

Masato Yoshikane

Kenichi Sugano

Emi Mamada

Yusuke Ichino

'A gypsum-based embedding material' is provided with which favorable casting can be conducted not only in the case where a conventional wax pattern is used, but also, in particular, in the case where a resin pattern different from the conventional wax pattern in disappearance temperature and disappearance behavior is used, and with which, although being a 'gypsum-based embedding material', occurrence of cracks, breakage, or the like in a mold is suppressed even when casting is conducted by &#x201c;rapid heating&#x201d; excellent in treatment efficiency. The gypsum-based embedding material composition for casting comprising, as main components, calcined gypsum as a binder, cristobalite and quartz as heat-expandable refractory materials, and a non-heat-expandable refractory material having an average particle diameter of 5 to 20 &#x3bc;m, the blending amount of the non-heat-expandable refractory material in 100 parts by mass of the main components being 10 to 25 parts by mass.

Gypsum-based embedding material composition for casting

The object of the present invention is to provide an embedding material composition for casting that makes it possible to conduct a favorable casting in the case where casting is conducted using a resin pattern that is different from a conventional wax pattern in disappearance temperature and disappearance behaviors through 'rapid heating' excellent in treatment efficiency. The present invention relates to an embedding material composition for casting not using a heat-expandable refractory material as a main component, comprising: a binder; and a non-heat-expandable refractory material having an average particle diameter of 5 to 20 &#x3bc;m as main components, in which a content of the binder is 25 to 40 parts by mass and a content of the non-heat-expandable refractory material is 60 to 75 parts by mass in the case where the total amount of the main components is 100 parts by mass, and the present invention also relates to a casting process using the embedding material composition for casting.

Casting investment composition and casting process using same

Provided is a coloring agent composition to be added to a gypsum-containing raw material powder constituting a gypsum product and to be used for coloring the gypsum product, the coloring agent composition being a powder containing a pigment, calcined gypsum, and amorphous silica. A process for producing the coloring agent composition includes a first step of mixing a pigment, calcined gypsum, and amorphous silica to obtain a mixed powder. Use of the coloring agent composition makes it possible to easily produce gypsum products such as a powder and a hardened body that are excellent in colorability.

Coloring agent composition and method for producing same

An object of the present invention is to provide a high-expansion gypsum composition in which the expansion coefficient of a general purpose dental gypsum material or the like is simply and effectively improved to such an extent that has never been achieved with conventional technologies without using any special material by adding an inexpensive additive even in a small addition amount, and furthermore another object of the present invention is to provide a high-expansion gypsum composition the setting expansion coefficient of which is appropriately controlled so that the contraction of a resin to be used can be precisely dealt with, the high-expansion gypsum composition being useful for manufacturing a reproduction model to be used in manufacturing a 'non-clasp denture' having no problem in, for example, occlusion (adaptability). The objects of the present invention are achieved by means of a method for producing a high-expansion gypsum composition, the method producing a gypsum composition having an enhanced setting expansion coefficient by copulverizing in a dry system a powdered gypsum composition containing calcined gypsum as a main component and dihydrate gypsum.

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Tokyo, Japan

Masato Yoshikane