PURPOSE: To manufacture a hard contact lens of favorable optical performance, by a method wherein a monomer or a monomer mixture is reacted by heating the same under agitation in the presence of a polymerization inhibitor and a crosslinking agent, reaction is interrupted by cooling a reactive solution at a point of time when viscosity of the reactive solution is raised to a specific range and polymerization and curing are effected to a prepolymer by putting the prepolymer into a mold.
CONSTITUTION: A polymerizing stock solution obtained by adding an appropriate quantity of a crosslinking agent and polymerization inhibitor to a monomer or a mixed solution of monomers is provided within a reaction vessel. The provided stock solution is heated at a fixed temperature while the same is being agitated. The polymerization reaction is suspended by suspending heating and agitation, then cooling immediately when the viscosity of the polymerization reaction solution has arrived at a desired viscosity to obtain a desired prepolymer. It is necessary that the viscosity falls within a range of 10W2,000cps. It is preferable to prepare a prepolymer of a viscosity as high as possible within a predetermined range of the viscosity.
OKUBO TAKESHI
SAWAMOTO TAKEYUKI
TARUMI JIRO
KOMIYA SHIGEO
ONOZUKA SHIGEHARU
FUTAMURA HIDEYUKI
