Compositions – Light transmission modifying compositions – Displaying color change
Reexamination Certificate
2000-09-06
2001-10-02
Lambkin, Deborah C. (Department: 1626)
Compositions
Light transmission modifying compositions
Displaying color change
C549S382000, C544S150000
Reexamination Certificate
active
06296785
ABSTRACT:
DESCRIPTION OF THE INVENTION
The present invention relates to certain novel naphthopyran compounds. More particularly, this invention relates to novel indeno-fused photochromic naphthopyran compounds and to compositions and articles containing such novel naphthopyran compounds. When exposed to light radiation containing ultraviolet rays, such as the ultraviolet radiation in sunlight or the light of a mercury lamp, many photochromic compounds exhibit a reversible change in color. When the ultraviolet radiation is discontinued, such a photochromic compound will return to its original color or colorless state.
Various classes of photochromic compounds have been synthesized and suggested for use in applications in which a sunlight-induced reversible color change or darkening is desired. U.S. Pat. No. 3,567,605 (Becker) describes a series of pyran derivatives, including certain benzopyrans and naphthopyrans. These compounds are described as derivatives of chromene and are reported to undergo a color change, e.g., from colorless to yellow-orange, on irradiation by ultraviolet light at temperatures below about −30° C. Irradiation of the compounds with visible light or upon raising the temperature to above about 0° C. is reported to reverse the coloration to a colorless state.
U.S. Pat. No. 5,066,818 describes various 3,3-diaryl-3H-naphtho[2,1-b]pyrans as having desirable photochromic properties, i.e., high colorability and acceptable fade, for ophthalmic and other applications. Also disclosed by way of comparative example in the '818 patent are the isomeric 2,2-diaryl-2H-naphtho[1,2-b]pyrans, which are reported to require unacceptably long periods of time to fade after activation.
U.S. Pat. No. 3,627,690 describes photochromic 2,2-di-substituted-2H-naphtho[1,2-b]pyran compositions containing minor amounts of either a base or weak-to-moderate strength acid. The addition of either an acid or base to the naphthopyran composition is reported to increase the fade rate of the colored naphthopyrans, thereby making them useful in eye protection applications such as sunglasses. It is reported therein further that the fade rate of 2H-naphtho-[1,2-b]pyrans without the aforementioned additives ranges from several hours to many days to reach complete reversion.
While the activated form of a typical organic photochromic molecule absorbs in the visible region over a relatively narrow range (Van Gemert and Kish, PPG Technology Journal, Vol. 5, pg. 53-61, 1999), broader absorbing naphthopyrans (i.e. those having two absorption bands), are not unknown. U.S. Pat. No. 5,645,767 discloses photochromic indeno[2,1-f]naphtho[1,2-b]pyrans having a blue/gray activated color. A blue/gray color will be perceived when there is a major absorption of visible light in the 580-620 nm range coupled with a minor absorption in the 420-500 nm range.
International Patent Application Publication No. WO 99/15518 discloses photochromic indeno[2,1-f]naphtho[1,2-b]pyrans having a green activated color. A green color will be perceived when there is a major absorption of visible light in the 580-620 nm range coupled with a major absorption of roughly equal intensity in the 400-480 nm range.
While it is obvious from the previous description that it is possible to obtain many complex activated colors, it is not disclosed in the aforementioned patent or application how to select substituents for both the pyrano and the indeno-fused naphtho portions of the indeno[2,1-f]naphtho[1,2-b]pyran in order to control the wavelength and/or intensity of the absorbance bands within the activated visible spectra.
The present invention discloses what types of substituents and where they may be placed in order to control the wavelength and/or intensity of the visible absorbance bands of indeno[2,1-f]naphtho[1,2-b]pyrans having 2 intense spectral bands in the visible spectrum.
These novel naphthopyrans are substituted with weak to moderate electron donor groups at the 3-position of the pyran ring and have either moderate to strong electron donor groups at the 6- and 7-position or a cyclic group fused to the h face. The compounds may optionally have at the 8-position moderate to strong electron donor groups and may have other substituents at the 5-, 8-, 9-, 10-, 11-, 12- or 13-positions of the compound. The selection and placement of these substituents being so that that the photochromic compounds of the present invention have a rating of at least 80 in the Relative &Dgr;OD at Saturation Test, described hereinafter.
Generally, the activated (colored) form of these photochromic compounds have an optical density of band “A” which is of greater intensity than the optical density of band “B”. The absorption of band “A” occurs in the 420-500 nm region while the absorption of band “B” occurs in the 500-650 nm region of the activated visible spectrum. These compounds exhibit an apparent blended gray, brown or green activated color. The use of certain individual compounds of the present invention substantially eliminates the need for combining two or more compounds to obtain neutral colors such as gray or brown. In addition, these compounds have demonstrated a high molar absorptivity (or molar extinction coefficient) in the ultraviolet (UV) light range, an acceptable fade rate without the addition of acids or bases, a high activated intensity and a high coloration rate.
DETAILED DESCRIPTION OF THE INVENTION
In recent years, photochromic plastic materials, particularly plastic materials for optical applications, have been the subject of considerable attention. In particular, photochromic ophthalmic plastic lenses have been investigated because of the weight advantage they offer, vis-a-vis, glass lenses. Moreover, photochromic transparencies for vehicles, such as cars and airplanes, have been of interest because of the potential safety features that such transparencies offer.
In accordance with the present invention, it has now been discovered that certain novel indeno[2,1-f]naphtho[1,2-b]pyrans having two absorption bands in the activated (colored) state, an acceptable fade rate, high activated intensity, a high coloration rate and a rating of 80 or higher in the Relative &Dgr;OD at Saturation Test may be prepared. The Relative &Dgr;OD at Saturation Test is described in Example 21. The ratings of the test are defined herein as the result obtained when the optical density of band “A” is divided by the optical density of band “B” and multiplied by 100. It is believed that compounds having a rating of 80 or higher are most valuable for formulating neutral grays, greens and browns for commercial photochromic ophthalmic eyeware.
The naphthopyrans of the present invention may have a rating in the Relative &Dgr;OD at Saturation Test of at least 80, preferably at least 90, more preferably from 90 to 150 and most preferably, from 100 to 130. The rating is expected to be less than 500, preferably less than 400, more preferably less than 300 and most preferably less than 200. The rating for the naphthopyrans may range between any combination of these values, inclusive of the recited values, e.g., from at least 80 to less than 500. The naphthopyrans of the present invention may have a rating greater than 500 if the two absorption bands are distinguishable and an optical density is obtainable for the calculation.
Preparation of such compounds is achieved by balancing the effects of the potential substituents as described hereinafter. For example, the “A” band of these compounds can be enhanced relative to the “B” band by employing strong electron donor substituents in the 7-position, moderate electron donors in the 6-position, and weak to moderate electron donors in the 3-position of the pyran ring. Compounds having relatively equivalent intensity for the “A” and “B” bands can be obtained by having electron donors of relatively equal intensity at the 6- and 7-positions and weak to moderate electron donors at the 3-positi
Chopra Anu
Gemert Barry Van
Knowles David B.
Kumar Anil
Nelson Clara M.
D'Souza Andrea M.
Lambkin Deborah C.
Mallak Frank P.
PPG Industries Ohio Inc.
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