Method of producing honeycomb structural bodies consisting of barium titanate series ceramics having a positive temperature coefficient of electric resistance

Claim 1

A method of producing a honeycomb structural body consisting of barium titanate series ceramics having a positive temperature coefficient of electric resistance, comprising kneading raw material powders, which contain at least 50% by weight of powders having perovskite type crystal structure and have a particle size distribution that 5-50% by weight of the raw material powders has a particle size of not smaller than 10 μm and 10-60% by weight thereof has a particle size of not larger than 2 μm, together with water and at least two kinds of organic binders to prepare a green mass, extruding the green mass into a honeycomb shaped article, drying the extruded article by blowing air through the channels of the honeycomb article at a rate of at least 50 cm/sec until the water content of the article becomes less than 5% by weight wherein the temperature of the air employed is less than 40° C., and firing the dried article, wherein said at least two kinds of organic binder are different by at least 50° C. in the decomposition temperature or weight decreasing temperature between a binder having the highest decomposition temperature or weight decreasing temperature and another binder having the lowest decomposition temperature of weight decreasing temperature.

Claim 2

A method of producing a honeycomb structural body consisting of barium titanate series ceramics having a positive temperature coefficient of electric resistance, comprising kneading raw material powders, which contain at least 50% by weight of powders having perovskite type crystal structure and have a particle size distribution that 5-50% by weight of the raw material powders has a particle size of not smaller than 10 μm and 10-60% by weight thereof has a particle size of not larger than 2 μm, together with water and at least two kinds of organic binders to prepare a green mass, extruding the green mass into a honeycomb shaped article, drying the extruded article by blowing air through the channels of the honeycomb article at a rate of at least 50 cm/sec until the water content of the article becomes less than 5% by weight wherein the temperature of the air employed is less than 40° C., and firing the dried article, wherein said at least two kinds of organic binder are different by at least 50° C. in the decomposition temperature or weight decreasing temperature between a binder having the highest decomposition temperature or weight decreasing temperature and another binder having the lowest decomposition temperature of weight decreasing temperature.