Patent ID: 8211993

Claim:
A method of manufacturing an inorganic substrate having a thin silica type glass layer of 2H to 9H pencil hardness, said method comprising the following first step (1) and second step (2); (1) coating an inorganic substrate with (A) a cyclic dihydrogenpolysiloxane that is liquid at ambient temperature, has a weight-average molecular weight within the range of 1500 to 1,000,000, and is composed of H 2 SiO 2/2 units, (B) a hydrogenpolysiloxane that is liquid at a temperature below 120° C., has a weight-average molecular weight within the range of 500 to 1,000,000, and is expressed by the following siloxane unit formulas: [H 2 SiO 2/2 ] x [HSiO 3/2 ] y [SiO 4/2 ] z (where x, y, and z express mole concentrations and where the following conditions are observed: 0.12≦x<1.0; 0≦y≦0.88; 0≦z≦0.30; y and z cannot be concurrently equal to 0; and x+y+z=1) or [H 2 SiO 2/2 ] v [HSiO 3/2 ] w (where v and w express mole concentrations and where the following conditions are observed: 0.12≦v<1.0; 0≦w≦0.88; and v+w=1) wherein the hydrogenpolysiloxane expressed by the unit formula: [H 2 SiO 2/2 ] x [HSiO 3/2 ] y [SiO 4/2 ] z a has been produced by subjecting (a) dihydrogendichlorosilane (H 2 SiCl 2 ), (b) hydrogentrichlorosilane (HSiCl 3 ), (c) tetraalkoxysilane (Si(OR) 4 ), or tetrachlorosilane (SiCl 4 ) to co-hydrolyis and condensation in a mixture of a non-polar organic solvent, hydrochloric acid, and ionic surface-active agent, the components (a), (b), and (c) being used in such mole concentrations that ensure the following conditions: 0.12≦a<1.0; 0≦b≦0.88; 0≦c≦0.30; b and c cannot be concurrently equal to 0; and (a)+(b)+(c)=1), and the hydrogenpolysiloxane expressed by the unit formula: [H 2 SiO 2/2 ] v [HSiO 3/2 ] w has been produced by hydrolyzing and condensing dihydrogendichlorosilane in a mixture of water with a non-polar inorganic solvent, and subsequently by branching the resulting dihydrogenpolysiloxane by mixing the non-polar solvent solution that contains the resulting dihydrogenpolysiloxane with an inorganic acid and a protonic polar solvent, or a mixture of the cyclic dihydrogenpolysiloxane (A) and the hydrogenpolysiloxane (B); and (2) curing the coated cyclic dihydrogenpolysiloxane (A), the coated hydrogenpolysiloxane (B), or the coated mixture of the cyclic dihydrogenpolysiloxane (A) and the hydrogenpolysiloxane (B) to form a thin silica type glass layer of 2H to 9H pencil hardness.