| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polymethylsilsesquioxane curable into a flexible crack-free product having excellent tensile strength by adding water to an organic oxygenous solvent or a mixed solvent comprising this solvent and a specified or smaller amount of a hydrocarbon solvent to form a suspension and adding dropwise a methyltrihalosilane to the suspension to effect its hydrolytic condensation. SOLUTION: Water (10-3,000 pts.wt.) is added to an oxygenous solvent such as methyl ethyl ketone or a mixed solvent comprising this solvent and at most 50 vol.% hydrocarbon solvent to form a two-phase system. To this system, 100 pts.wt. methyltrihalosilane represented by the formula: MeSiX3 (wherein Me is methyl; and X is a halogen) is added to effect its hydrolytic condensation to form a curable polymer represented by the formula and having a number- average molecular weight of 380-2,000. In a graph where the abscissae represent values of 1/(M×10-3), and the ordinates represent values of m/(m+n), the values of m/(m+n) lie within the region confined by four straight lines represented by the equations: m/(m+n)=0.152/(M×10-3)+0.10; 1/(M×10-3)=1000/2000; 1/(M×10-3)=1000/380; and m/(m+n)=0.034/(M×10-3) or on these lines. |
