Invention Grant
US08270089B2 Thermoplastic polyurethane lenses with a specified weight percentage of urethane repeating units 有权
具有指定重量百分比的聚氨酯重复单元的热塑性聚氨酯透镜

Thermoplastic polyurethane lenses with a specified weight percentage of urethane repeating units
Abstract:
A method of forming thermoplastic polyurethane (TPU) into an optical lens. Suitable TPUs contain urethane (—NHCOO—) repeating units that are present in at least 23% by weight. This range of urethane weights is an indicator of a flexural modulus above 1,400 MPa. The TPUs have refractive indices above 1.54 and Abbe numbers above 27. They have glass transition temperatures above about 100 degrees C. The selected TPU can be injection molded to form ophthalmic lenses, that are well suited for use in rimless spectacles. The lenses are highly solvent resistant, while at the same time being readily tintable. The lenses made according the invention meet FDA 21 CFR 801.41 Impact Requirement, and ANSI Z87.1 high velocity impact (HVI) standard.
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