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Abstract

A method for manufacturing soft contact lens buttons includes the steps of providing a unique monomeric mixture and polymerizing the mixture in an open mold in a non-convecting environment. In one preferred embodiment the monomeric mixture includes purified 2-hydroxyethyl methacrylate and between about 0.015 to about 0.10% by weight diethylene glycol methacrylate. The polymerizing step includes a first heating at 70.degree. C. for about one-and-one-half hours and a second heating at about 105.degree. C. for about two hours. The mold is composed of material that softens at the temperatures it is subjected to during the polymerization process. The non-convecting environment allows longer polymerization times to be used without evaporating volatile components. Lower temperatures, and an open and deformable mold, reduces stresses the hardening button is subjected to, to yield a stronger and tear-resistant product.

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First Claim