PURPOSE: To produce a new non-toxic coating material having an antifouling function in combination with a rustproofing function and free from environmental pollution by adding a specified filler to a (denatured) water glass vehicle which is prepared by a specified method.

CONSTITUTION: Polyethylene glycol or polypropylene glycol (polymerization degree is 2 to 2000) having functional groups is initially added to a solution of a silicate of the formula [M is K, Na, etc.; (n) is 2 to 31 and the resultant mixture is reacted to obtain an elastic get (PSE) having a high silicate content. The obtained PSE is then dissolved in a solution of a silicate of the formula [provided that (n) is 3 to 51 so that the weight ratio of PSE/SiO2 may be 0.1 to 100. An aluminium compound such as aluminium sulfate is subsequently added thereto so as to have 0.05 to 5 molar ratio of Al2O3/SiO2 and the resultant mixture is then heated and denatured at 30 to 100°C to obtain a silicate colloid vehicle. A filler selected from an ion-exchange alumosilicate, powdery Zn, powdery Al, a fine powder of their alloy, an alkaline earth metal and a metal oxide is then added to the vehicle and a pigment is subsequently added thereto.