Organic photochromic materials with high refractive index, their

Details Organic photochromic materials with high refractive index, their Organic photochromic materials with high refractive index, their

1997-04-21

1998-06-09

Morgan, Kriellion S.

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Processes of preparing a desired or intentional composition...

524104, 524110, 252586, C08K 535, C08K 534

Patent

active

057635110

DESCRIPTION:

BRIEF SUMMARY
This application claims the benefit of French Patent No. 94 15495 filed Dec. 22, 1994, and Provisional Application 60/001,677 filed Jul. 31, 1995, both entitled the same as above, by You-Ping Chan, David Henry, Remy Meyrueix and Jacques J. Vial.


FIELD OF THE INVENTION

This invention relates to novel organic photochromic materials with high refractive index and with adjustable properties, a method for their preparation and the articles formed from these materials.


BACKGROUND OF THE INVENTION

Co-assigned, U.S. patent application Ser. No. PCT/US95/14652, titled "Temperature Stable and Sunlight Protected Photochromic Articles," by Florent et al., filed concurrently herewith, discloses transparent organic photochromic materials having high refractive index, formed from a polymer matrix, which matrix can consist of a homopolymer of ethoxylated bisphenol A dimethacrylate having the formula I: ##STR1## where R=H or CH.sub.3, and m and n independently represent 1 or 2, and where optionally, the dimethacrylate is modified up to 30 wt % with an aromatic comonomer with vinyl, acrylic or methacrylic functionality, and where the material contains at least one dye that imparts photochromic properties to the matrix, the dye being selected from spirooxazines, spiropyrans and chromenes.
These materials can be prepared by a method consisting of polymerizing a methoxylated bisphenol A dimethacrylate with the above-mentioned formula I, optionally in the presence of one or more aromatic monomers with vinyl, acrylic or methacrylic functionality, in the presence of a diazo radical initiator, such as azobisisobutyronitrile, and in the absence of a peroxide radical initiator.
Because of the absence of a peroxide initiator, it is possible to incorporate one or more photochromic dyes, selected from spirooxazines, spiropyrans and chromenes, directly into the polymerizable monomer to obtain a matrix which is dyed in bulk. According to the Florent et al. reference, it is also possible to polymerize the polymerizable mixture containing the monomer and the photochromic dye in a lens mold to obtain directly a photochromic lens. In a variant, they also disclose that it is possible to polymerize the monomer without dye and to subsequently dye the matrix obtained (which matrix can be in the form of a lens for example), using photochromic dyes, for example by a method of thermal diffusion, as described in U.S. Pat. Nos. 5,130,353; 5,185,390; and 5,180,254 for example. Typically in a thermal diffusion process, a substrate which is impregnated with one or more photochromic dyes is applied to one side (usually the convex side in the case of a lens) of the polymer matrix, and the mixture is heated at 100.degree.-150.degree. C. for 1 to 3 hours, and finally the substrate is separated from the matrix.
The matrix of the above-mentioned patent application, associated with one or more photochromic dyes, presents essentially constant photochromic characteristics (kinetics, heat dependence). It would be useful to be able to change the photochromic characteristics of the above-mentioned materials in order to better adapt the photochromic material to various applications. Accordingly, it is the object of the present invention to meet this requirement by providing organic photochromic materials having adjustable photochromic properties.


SUMMARY OF THE INVENTION

Briefly, the present invention is directed to organic photochromic materials having adjustable photochromic properties formed by copolymerizing monomers having formula I above with specific polyurethane oligomers.
More specifically, the invention relates to organic photochromic materials consisting of a polymer matrix with optical quality, having a refractive index of at least 1.54 and containing at least one dye that imparts photochromic properties to the matrix, the dye being selected from the group of spirooxazines, spiropyrans and chromenes. The polymer that constitutes the matrix is a copolymer consisting of (i) 30-95 wt % ethoxylated bisphenol A dimethacrylate having the following form

REFERENCES:
patent: 5585042 (1996-12-01), Knowles
patent: 5683628 (1997-11-01), Mizuno et al.

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