An improved lens of diethyle glycol bis allyl carbonate CR-39 and a process for preparation thereof

Abstract

An improved lens comprising CR-39 and polytoiol in the ratio of 30-50% of CR-39, 70-50% of polythiol and total weight of TDI and CR-39 is 25-50% by weight of the total material and wherein CR-39, Polythiol and TDI is present preferably in the ratio of 31-32%, 31-32% and 36-38% respectively wherein the Refractive Index of the lens is in the order of 1.59-1.65.

Description

technical field [0001] The present invention relates to an improved lens of diethylene glycol bisallyl carbonate CR-39 and its preparation method. Background technique [0002] Plastic lenses are classified based on their index of refraction, and the index of refraction determines the light intensity of the lens. Therefore, if a lens with a low refractive index is used for higher light intensities, the lens needs to have a substandard thickness, which increases the wearer's discomfort due to the weight of this lens. In this case, the preferred touse is a lens with a high refractive index. [0003] Lenses with a high refractive index of 1.6 and above have generally been produced hitherto from polythiols. The process involves first preparing a diol from mercaptoth, ethanol and epichlorohydrin in the presence of triethylamine as a catalyst. The ratio of catalyst to active ingredient is 1:1, and the reaction is carried out at a temperature above 40°C. [0004] The diol is th...

AI Technical Summary

Problems solved by technology

[0008] As this method of making lenses, it is known in the art that CR-39 resin is polymerized for a period of 17-20 hours in the presence of diisopropyl peroxide (DIPP), which is time-consuming