Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2000-09-06
2002-02-19
Ramsuer, Robert W. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C544S150000, C546S196000, C252S586000
Reexamination Certificate
active
06348604
ABSTRACT:
DESCRIPTION OF THE INVENTION
The present invention relates to certain novel naphthopyran compounds. More particularly, this invention relates to novel 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. U.S. Pat. No. 5,458,814 discloses 2H-naphtho[1,2-b]pyrans substituted in the 5- and 6-positions that possess a reasonable rate of fade as well as high colorability. The compounds exhibit activated colors ranging from yellow to red/purple.
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), naphthopyrans having two absorption bands, are known. 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 greenish 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.
International Patent Application Publication No. WO 98/42693 describes naphtho[1,2-b]pyrans having amino functional groups as substituents at the 7- or 9-positions of the naphthopyran ring. These compounds are disclosed as exhibiting a brown or red/brown activated color. A red/brown color will be perceived when there is a major absorption of visible light in the 420-500 nm range coupled with a minor absorption in the 520-560 nm range.
International Patent Application Publication No. WO 98/04937 describes naphtho[1,2-b]pyrans having alkoxy groups as substituents at the 7- and 9-positions of the naphthopyran ring. The activated forms of these compounds exhibit two intense absorption bands in the visible light range. It is reported that the optical density of the band absorbing at lower wavelengths (band “A”) in some cases is higher than the optical density of the band absorbing at higher wavelengths (band “B”), but in the majority of cases the band “A” is of lower optical density than band “B”.
International Patent Application Publication No. WO 00/35902 describes 2H-naphtho[1,2-b]pyrans having various substituents. It is disclosed that when a substituent is present at the 5 carbon atom of a 2,2-diaryl-2H-naphtho[1,2-b]pyran, the intensity of the color generated can be enhanced by placing an electron-releasing group at the 8 carbon atom. This effect may be further augmented by placing additional electron-releasing groups at carbon atoms 7 and/or 10. It is further disclosed that the intensity of the generated color can be diminished by placing electron-releasing substituents at carbon atoms 9 or 7. There is no mention in this application of the naphthopyrans having multiple absorption bands nor the relative intensities of such bands.
While it is obvious from the previous description that it is possible to obtain many complex activated colors, it is not disclosed in any of these patents or applications how to select substituents for both the pyrano and the naphtho portions of the 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 2H-naphtho[1,2-b]pyrans having 2 intense spectral bands in the visible spectrum. Such 2H-naphtho[l,2-b]pyrans are essentially characterized by either two adjacent moderate to strong electron donor substituents at the 8 and 9 positions or a fused heterocyclic group formed by the substituents at the 8 and 9 positions coming together and at the 2 position, weak to moderate electron donor substituent(s). The compounds of the present invention also have a substituent at the 5 position and an optional substituent at the 6 position. The selection and placement of these substituents being done so that the photochromic naphthopyrans demonstrate a rating of at least 80 in the Relative &Dgr;OD at Saturation Test, described hereinafter.
Clearly with this understanding, not only can compounds exhibiting colors including an apparent blended brown, gray or a green activated color be obtained, but one skilled in the art can now fine tune the activated visible spectrum to meet specific needs. For example, the use of certain individual compounds of the present invention may eliminate the need for combining two or more compounds to obtain a preferred shade or version of the 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. These compounds are also reported to be more resistant to fatigue than other compounds having equal absorbance in the 400 to 500 nanometer range.
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 2H-naphtho[1,2-b&rsqb
Chopra Anu
Gemert Barry Van
Knowles David B.
Kumar Anil
Nelson Clara M.
D'Souza Andrea M.
Mallak Frank P.
PPG Industries Ohio Inc.
Ramsuer Robert W.
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