Ceramic green sheet and method for producing the same

摘要

The invention provides a ceramic green sheet having plasticity, punching property, and sinterability of satisfactory levels as well as a low percent (heat) shrinkage. In the production of a ceramic slurry serving as a raw material of the sheet, ingredients thereof are mixed under such conditions that the functional group ratio (polyol to isocyanate) is 1.5/11.5 to 11.5/11.5; the urethane resin formed from isocyanate and polyol has a repeating-unit-based molecular weight of 290 to 988; and the ratio by weight of the urethane resin to a ceramic powder falls within a range of 4.5 to 10 parts by weight of the urethane resin with respect to 100 parts by weight of the ceramic powder. A ceramic green sheet having, in well balance, all of the properties (i.e., plasticity, punching property, sinterability, and (heat) shrinkage) required for facilitating subsequent processes such as mechanical working and firing can be provided.

主权项

1. A thin ceramic green sheet which comprises a ceramic powder, and a urethane resin serving as a binder and formed by mixing an isocyanate and a polyol, wherein:
the ratio by mole of hydroxyl group of the polyol which is employed for mixing to isocyanate group of the isocyanate which is employed for mixing falls within a range of 2/11.5 to 5/11.5; the urethane resin has a repeating unit-based molecular weight in a range of 290 to 988, said urethane resin repeating unit-based molecular weight being defined as the sum of a value obtained by dividing the molecular weight of an isocyanate group by the isocyanate group content of the isocyanate which is employed for mixing and a value obtained by dividing the molecular weight of a hydroxyl group by the hydroxyl group content of the polyol which is employed for mixing; and the ratio by weight of the urethane resin to the ceramic powder contained in the ceramic green sheet falls within a range of 7 to 10 parts by weight of the urethane resin with respect to 100 parts by weight of the ceramic powder.