Compositions – Light transmission modifying compositions – Displaying color change
Reexamination Certificate
1999-11-23
2001-02-20
Lambkin, Deborah C. (Department: 1627)
Compositions
Light transmission modifying compositions
Displaying color change
C524S110000, C549S389000, C548S143000, C548S217000, C548S238000
Reexamination Certificate
active
06190580
ABSTRACT:
TECHNICAL FIELD
The present invention relates to photochromic diaryl-naphtopyrans.
STATE OF THE ART
Pyrans have been known as photochromic compounds for 25 years. One of the first descriptions of pyrans is in U.S. Pat. No. 3,567,605, in which the various benzo- and naphthopyrans including diphenyl-naphtopyrans are also described. However for years these compounds have remained uninteresting, because they only dye at very low temperatures (−40° C.).
Only recently have pyrans become known that also dye photochromically at normal temperatures and thus seem suited for use in ophthalmic lenses. Reference is made, by way of example, to U.S. Pat. No. 5,066,818, WO 93/10112 or WO 92/09593.
However, these known pyrans still have drawbacks with regard to their longevity and/or migration properties as well as their photochromic properties.
In particular, the material specific varying migration of the individual pyran compounds leads to inadequate dyeing results in surface coloring if these pyran compounds are utilized in mixtures, which are needed to obtain a desired mixed tone, because each individual compound penetrates to a different depth into the to-be-dyed material depending on the specific migration velocity.
The result are, comparable to the procedures in chromatography, layers in which the different pyran compounds are found in above average concentrations.
Moreover, the relatively great migration velocity of the compounds known from the state of the art results in a short lifetime of the dyed plastic objects. The known dyestuffs migrate relatively quickly out of the dyed object to its surface and cause separation phenomena there.
The nomenclature used for photochromic naphthopyrans is illustrated by the structural formulae shown below:
The two structures at the top are identical, as are the two structures at the bottom. However, each top structure differs from each bottom structure in the position of the oxygen atom (0) in the pyran ring and the position of the carbon atom to which the two aryl groups are attached. These aryl groups are substituents which each have replaced a hydrogen atom.
The numbering of the ring atoms in the two structures on the left is in accordance with nomenclature in which the oxygen atom in the pyran ring is given the number 1 and the count proceeds around the pyran ring. The aryl groups are then always attached to the carbon atom which has the number 2. Thus, both the top compound and the bottom compound, although different from each other, are termed diaryl-2H-naphthopyrans, the designation 2H indicating that the two aryl groups are attached to the number 2 carbon atom in place of hydrogen atoms. In order to distinguish the top structure from the bottom structure the top structure may be termed the Y form and the bottom structure the Z form.
The numbering of the ring atom in the two structures on the right is in accordance with a different nomenclature which is frequently used in the literature, for example in the U.S. Pat. No. 5,066,818 (Gemert, et al), column 2, or U.S. Pat. No. 5,623,005 (Rickwood, et al) abstract, where the count commences in the pyran ring with the atom that is attached to the a carbon atom of the naphthalin system and proceeds around the ring. Thus, contrary to the nomenclature described in the preceding paragraph. The compound at top right is termed a diaryl-3H-naphthopyran, whereas the compound at bottom right is termed a diary-2H-naphthopyran, as before.
The last indicated nomenclature is used for the present application. According to this nomenclature most of the compounds mentioned in the specification, for example in Table 1, would be diaryl-3H-naphthopyrans, where the oxygen atom is attached to the P carbon atom of the naphthalin system. The described synthesis in which 6-methoxy-2-naphthol is used, as stated at the bottom of page 11, can only lead to diaryl-3H-naphthopyrans. The mixture of compounds obtained according to one embodiment of the present invention, contains diaryl-2H-naphthopyrans, diaryl-3H-naphthopyrans as well as naphthopyrans having a hybrid structure of both diaryl-2H- and diaryl-3H-naphthopyrans;
DESCRIPTION OF THE INVENTION
The object of the present invention is to provide substances, which dye photochromically well at room temperature, lighten up quickly enough for ophthalmic lenses, possess sufficient longevity and due to their spatial structure have less tendency to migrate than the compounds known from the state of the art, and to describe the synthesis of these substances.
An invented solution to this object is set forth in claims 1 and 2.
Further improvements of the present invention are the subject matter of the dependent claims.
The subject matter of the present invention are therefore photochromic compounds having a diaryl-naphthopyran-structure, which possesses an advantageous substitution at its aryl substituents.
On the one hand, this substitution of the aryl substituents comprises linking the naphthopyran-structure to the first starting compound described in claim 2 under a) by means of the invented process, with which ‘monomeric’ diaryl-naphthopyrans which possess one photochromically reacting center are produced.
On the other hand, the photochromic substance yielded by the described process possesses an especially advantageous substitution of the aryl substituents if the aryl substituent of the diaryl-naphthopyran compound is linked via the starting compound described in claim 2 under a) to at least one other diaryl-naphthopyran compound.
Dependent on the selection of the starting compound
the photochromic substance possesses a link of at least two photochromic partial systems, which either are characterized by an electron-conducting bridge or by a bridge that interrupts electron delocalization.
An element of the present invention is that it was understood that a solution to the object can succeed in a very simple manner by substituting the aryl substituents of the diaryl-naphthopyran compounds known from the state of the art in a suitable manner.
All the photochromic properties such as color, darkening and lightening up velocity, temperature dependency and longevity of the photochromic reaction are retained; at the same time the invented compounds show distinctly less tendency to migrate than the compounds known from the state of the art.
Moreover, various diaryl-naphthopyrans can be linked in this way. This has the advantage that several dyestuffs of varying absorption possess identical ability to migrate in an excited state or in an unexcited state, because they are located in a whole molecule. In this manner, various problems that occur with a variety of dyestuffs particularly in surface coloring can be elegantly avoided.
REFERENCES:
patent: 3567605 (1971-03-01), Becker
patent: 5066818 (1991-11-01), Gemmert et al.
patent: 5466398 (1995-11-01), Van Gemmert et al.
patent: 5623005 (1997-04-01), Rickwood et al.
patent: 5628935 (1997-05-01), Hughes et al.
patent: 5707557 (1998-01-01), Melzig et al.
patent: 5744070 (1998-04-01), Kumar
patent: 5759450 (1998-06-01), Hughes et al.
Melzig Manfred
Zinner Herbert
Antonelli, Terry Stout & Kraus, LLP.
Lambkin Deborah C.
Optische Werke G. Rodenstock
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