Optical articles comprising photochromic poly(urea-urethane)

Abstract

The process for producing a photochromic eyewear lens by forming at least a layer of modified photochromic poly(urea-urethane) by combining photochromic material and the reaction product of a polyurethane pre-polymer and a mixture of diethyltoluene diamine and one or more polyols, plus catalyst. The mixture comprises both NH2 and OH reactive groups, with at least 0.04 equivalent weights of OH reactive species available for reaction with each 1.0 equivalent weight of excess NCO reactive species available in the pre-polymer. The lens comprising the modified photochromic poly(urea-urethane) can exhibit faster fade-back rates and better photochromic performance than lenses with non-modified poly(urea-urethane).

Description

RELATED APPLICATION INFORMATION[0001]This patent is a continuation of U.S. patent application Ser. No. 15 / 909,841 filed Mar. 1, 2018 entitled OPTICAL ARTICLES COMPRISING PHOTOCHROMIC POLY(UREA-URETHANE), which claims priority of U.S. Provisional Application No. 62 / 465,639 filed Mar. 1, 2017 all of which are hereby incorporated by reference in its entirety.NOTICE OF COPYRIGHTS AND TRADE DRESS[0002]A portion of the disclosure of this patent document contains material which is subject to copyright protection. This patent document may show and / or describe matter which is or may become trade dress of the owner. The copyright and trade dress owner has no objection to the facsimile reproduction by anyone of the patent disclosure as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright and trade dress rights whatsoever.FIELD OF THE INVENTION[0003]The field of the invention relates generally to eyewear and more specifically to eyewear len...

AI Technical Summary

Benefits of technology

The invention relates to improved photochromic materials for use in eyewear lenses. The inventors found that while some materials can change color quickly, they are too soft to be effective in lenses. They modified the materials to make them slightly less soft, but not too damaging to be used in lenses. This resulted in faster response times and better durability.

Problems solved by technology

Variable lighting conditions can interfere with proper vision and acuity.

When subjected to sudden or drastic changes in illumination, the effects can range from minor inconvenience to disabling and dangerous loss of perception.

The eye requires a measureable amount of time to adjust to both lighter or darker conditions, and it is common (albeit extremely uncomfortable) to have a feeling of momentary blindness during these transitional periods.

However, there may be some limitations to this responsiveness.

Many photochromics absorb ultraviolet light and therefore may have limited response behind a window, such as when driving a car, or riding in a train.

Another limitation can be how quickly the photochromic molecules respond to changes in absorbed energy; it would be clearly unacceptable (and possible dangerous) if it took half an hour for a lens to lighten when one walked inside from a bright sunlit area.

As a practical matter, it has been found that the physical environment of the photochromic molecule may significantly affect the responsiveness and the lifetime of its performance.

In the gas or liquid phase, or in solution, this is not an issue, but when trapped within a solid matrix (within an eyewear lens, or applied onto a lens), many limitations can appear.

In addition, the photochromic molecules can “fatigue” (i.e., lessen in coloration or response) due to exposure to environmental conditions or repeated movement of the physical bonds.

It is often the case that improvement in one area is accompanied by poorer performance in another property.

However, in the development of new optical materials, and particularly those used for photochromic eyewear lenses or spectacle lenses, there is a constant challenge to provide a material that will allow sufficient open space within its structure to accommodate the required molecular rotation or rearrangement of the photochromic molecules, while still maintaining the strength, rigidity and structural resilience needed for a reliable and long-lasting eyewear lens.

It has been difficult to achieve both “darker and faster” in the same product, especially if increased speed of fade-back is desired.

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