Title:
【発明の名称】歯科鋳造用石膏系埋没材
Document Type and Number:
Japanese Patent JP2745006
Kind Code:
B2
Abstract:
PURPOSE:To obtain the title investment material by blending a mixture of cristobalite of refractory and/or quartz and hemihydrate of binder with natural starch and a specific transition metal compound as an expanding agent and aluminum phosphate as a cast cavity inhibitor. CONSTITUTION:100 pts.wt. mixture of cristobalite of refractory and/or quartz and hemihydrate as binder is blended with 0.1-5 pts.wt. natural starch and 0.1-10wt.% one or more of carbide, nitride, boride, silicide and sulfide of transition metal of groups IV, V and VI of the periodic table as an expanding agent and aluminum phosphate as cast cavity inhibitor to give a gypsum-based investment material having large thermal expansion and improved heat resistance of gypsum. The investment material is preferably blended with 0.1-1 pt.wt. soluble starch. The investment material is safe because of no evolution of toxic gas.
Inventors:
Yoshinobu Yamamura
Ken Iiyama
Hayashi Shohei
Ken Iiyama
Hayashi Shohei
Application Number:
JP18804490A
Publication Date:
April 28, 1998
Filing Date:
July 18, 1990
Export Citation:
Assignee:
GC Corporation
International Classes:
A61C13/20; A61K6/00; (IPC1-7): A61K6/00
Attorney, Agent or Firm:
Tadayuki Noma