To mold a strain-free optical lens by a method wherein a thermosetting silicone resin material containing an organopolysiloxane having a specified cold viscosity and a specified composition is poured in a molding metal mold until the overflowing of the material occurs so as to harden a molded article part after the gate parts on a bung hole side and on an overflowing part side are sealed by hardening.
A thermosetting silicone resin material containing an organopolysiloxane, the viscosity at normal temperature of which is 20-300 poise and an average compositional formula of which is: Rn(C6H5)mSiO(4-n-m)/2, in which R is the same kind or different kinds, substituent or non-substituent, aliphatic or clicyclid monovalent hydrocarbon group and 0.1-50 mol.% of R is aliphatic unsaturated hydrocarbon group, and (n) and (m) are positive numbers, which satisfy inequalities: 1≤n+m<2 and 0.02≤m/(n+m)≤0.8, is used. The above-mentioned molding material 5 is poured in a molding metal mold, the temperature of which is controlled to be a predetermined one. The pouring is stopped at the instant that the overflowing of the material starts. A nozzle 11 is left as being connected and, after the gate parts 7 and 7' are hardened, is disconnected. Thus, a ultra low pressure molding becomes possible, resulting in allowing to produce a molded article highly efficiently without molding strain.
SHIZUKUDA YOSHINARI
SHIMIZU TAKAO
NAGASAWA TSUTOMU
