Abstract: Provided is a polybenzoxazole precursor having a high purity which does not contain ionic by-products. The above polybenzoxazole precursor comprises a repetitive unit represented by Formula (1): wherein A1 represents a tetravalent aromatic group; N and OH which are bonded to A1 are paired, and the respective pairs of N and OH are bonded to carbons which are adjacent to each other on the same aromatic ring; A2 represents a divalent organic group; and n represents a number of 2 to 300.

Abstract: Provided is a polybenzoxazole precursor having a high purity which does not contain ionic by-products.

Abstract: A non-toxic antifouling coating composition comprising (a) about from 5 to 95 parts by weight as the resin solid content of a room temperature-curable silicone rubber having a number-average molecular weight of about from 20,000 to 100,000, (b) about from 5 to 95 parts by weight as the resin solid content of a room temperature-curable silicone rubber having a number-average molecular weight of about from 500 to 20,000, (c) silicone oil in an amount of about from 20 to 200 parts by weight per 100 parts by weight of the total solids of the rubbers (a) and (b), and (d) hydrophobic fumed silica in an amount of about from 5 to 30 parts by weight per 100 parts by weight of the total solids of the rubbers (a) and (b), provides a non-toxic antifouling coating composition which is capable for forming a coating film having highly improved antifouling properties and antifouling durability for a long period of time.

Abstract: A non-toxic antifouling coating composition containing 50 to 99% by weight as the resin solid content of (A) a reaction-curable silicone resin composition and 1 to 50% by weight a solid content of (B) a silicone resin having an average molecular weight of 250 to 30,000, a viscosity of 20 to 50,000 centistokes and alkoxy group at its molecular terminal, and represented by the general formula (I): ##EQU1## where R is hydrogen atom, alkyl group having 1-10 carbon atoms, aryl group or aralkyl group, R.sup.1 is bivalent aliphatic hydrocarbon group having 1-10 carbon atoms, which may be bonded directly or through ether group, ester group or --NH--group, R.sup.2 is lower alkyl group having 1-6 carbon atoms, X and Y are represented respectively as 0.01.ltoreq.X<4.0, 0.01.ltoreq.Y<4.0 and 0.02.ltoreq.X+Y<4.