To improve stiffness surface smoothness, peelability, cracking and deformation resistances by mixing ceramic powder with acrylic resin, a specified plasticizer and a specified solvent.

Ceramic powder is blended with acrylic resin having a wt. average mol.wt. of 150,000-500,000 made from alkyl (meth)acrylate having a 1-8C alkyl group, at least one kind of plasticizer selected from among dialkyl isohthalate, dialkyl terephthalate and trialkyl trimellitate as alkyl esters each having 4-18C alkyl groups and a ketone, alcohol or hydrocarbon solvent having ≤150°C b.p. A dispersant is further added if necessary. The amt. of the acrylic resin is 5-30 pts.wt. and that of the plasticizer is 3-2 pts.wt. based on 100 pts.wt. of the ceramic powder.