Low-fire green ceramic articles and slip compositions for producing same

Claim 1

In a slip composition for formation of green ceramic articles, a slurry comprising a finely divided inorganic powder blended with an organic polymeric binder and a volatile liquid medium; wherein said inorganic powder consists essentially of, by weight, A. 85-99% barium titanate, B. 0.5-10% bismuthate glass frit, and C. 0.5-5% fe 2 O 3 ; components (A), (B) and (C) being sufficiently finely divided to pass through a No. 325 screen, and said organic polymeric binder is 1-15% of the weight of the inorganic powder; said organic polymeric binder being selected from the class consisting of, by weight, 1 acrylate copolymers of 50-75% alkyl acrylate ester, 25-50% alkyl methacrylate ester, and 0.2-2% acrylic acid and methacrylic acid, wherein in said esters alkyl is one or more radicals selected from among methyl, ethyl, propyl, butyl or 2-ethylhexyl; 2. ethylene copolymers of i. 20-79.5% ethylene; ii. 20-79.5% of one or more comonomers from among vinyl esters of saturated 1-6 carbon atoms aliphatic monobasic carboxylic acids; butyl acrylate; vinyl-2-ethylhexoate; and dibutyl maleate; and iii. 0.5-10% of one or more comonomers from among acrylic acid, methacrylic acid, N-methylol acrylamide, itaconic acid; and glycidyl methacrylate; 3. and mixtures of (1) and (2); said slip composition on drying producing green ceramic articles which exhibit excellent storage life and which are fireable to ceramic articles at temperatures substantially below the sintering temperature of barium titanate.