The preliminary hardened material and production manner null designates silicon based chemical compound as the main component of the compact which uses

摘要

PROBLEM TO BE SOLVED: To obtain a precured product having high transparency by selecting a mixture comprising a silsesquioxane ladder polymer represented by a specified formula, a silicon compound having SiH groups, a silicon compound having vinylsilyl groups, and a platinum catalyst and showing a specified fluidity. ;SOLUTION: A silsesquioxane ladder polymer represented by the formula (wherein R¹ to R³ are each H or a monovalent organic group; (l), (m) and (n) are each 0 or a positive integer; and 2≤(l)+(m)+(n)) and having a number-average molecular weight of 500 or above is dissolved in a solvent such as tetrahydrofuran, and a silanol condensation catalyst comprising a titanium compound and water are added to the solution. Next, a solution prepared by dissolving a silicon compound having at least two SiH groups and a silicon compound having at least two vinylsilyl groups in tetrahydrofuran is mixed with the above silsesquioxane polymer solution, a platinum catalyst, and optionally a polyfunctional silicon compound and a silica cross-linking agent. The resulting solution is heated to about 50°C to form a precured product having a fluidity of 10^-1 to 10^-6cm³/s at 100°C. This product is preheated, then compression-molded at 50-500°C under a pressure of 1-500kgf/cm², and heat-treated to obtain a molding.;COPYRIGHT: (C)1997,JPO