Compositions – Light transmission modifying compositions – Displaying color change
Patent
1997-01-23
1998-07-07
Tucker, Philip
Compositions
Light transmission modifying compositions
Displaying color change
526204, G02B 523, C08F 200
Patent
active
057763763
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/JP96/01385 filed on May 24, 1996.
TECHNICAL FIELD
The present invention relates to a curable composition which can be suitably used for production of a photochromic cured product having excellent durability in photochromism.
BACKGROUND ART
Photochromism is a phenomenon which has come to draw attention in the last several years, and is such a reversible reaction that a certain compound quickly changes its color when irradiated with an ultraviolet-containing light such as sunlight or a light emitted from a mercury lamp and, when the light irradiation is stopped and the compound is placed in a dark room, returns to the original color. Compounds exhibiting photochromism are called photochromic compounds, and photochromic compounds having various structures have heretofore been synthesized. These conventional photochromic compounds, however, have a problem in that they are poor durability in photochromism.
There are known novel photochromic compounds having improved durability, such as fulgide-based photochromic compounds (hereinafter referred to simply as fulgide compound), chromene-based photochromic compounds U.S. Pat. Nos. 4,882,438, 4,960,678, 5,130,058 and 5,106,998; and Japanese Kokai (Laid-Open) Patent Application Nos. 2-28154, 3-11074 and 3-133988!.
Also in Japanese Kokai (Laid-Open) Patent Application No. 5-306392 is proposed combination use of a compound having an epoxy group(s) as a component for further improving the durability of fulgide compound.
These photochromic compounds and the cured product obtained by polymerizing and curing a photochromic curable composition containing said photochromic compound, generally show excellent durability in photochromism. In order to use a photochromic cured product obtained by polymerizing a photochromic curable composition containing such a photochromic compound and a polymerizable monomer(s), for various applications, the photochromic curable composition must have good durability in photochromism and excellent moldability and is capable of affording a cured product superior in various properties.
In the above-mentioned Japanese Kokai (Laid-Open) Patent Application No. 5-306392 is proposed a photochromic curable composition containing a compound having an epoxy group, the above-mentioned photochromic compound and, as a polymerizable monomer, a polyethylene glycol di(meth)acrylate. This composition, when polymerized and cured, gives a photochromic cured product having excellent durability in photochromism, but has the following problems. That is, the photochromic cured product has a high water absorption and, when stored over a long period of time, causes quality change with time owing to water absorption and in consequence, its photochromism at the initial stage is unstable. Moreover, since the composition has a high shrinkage after polymerization, releasing from a mold is liable to occur when such composition is cured in the mold, resulting in that it gives a defective cured product having a surface of poor appearance and a reduced yield in polymerization.
DISCLOSURE OF THE INVENTION
The present inventors have continued extensive studies on a curable composition which is prepared by polymerizing a mixture of the above-mentioned photochromic compound and a polymerizable monomer(s) to produce a photochromic cured product typified by a photochromic lens. As a result, the present inventors have found that a photochromic curable composition having the following specific composition is superior not only in durability in photochromism but also in moldability and that a cured product from the composition has excellent physical properties. The present invention has been accomplished based on the above finding.
The present invention resides in a photochromic curable composition comprising
a polymerizable monomer composed of 0.1 to 30 parts by weight of (A) a compound having at least one epoxy group in the molecule,
30 to 70 parts by weight of (B) a polypropylene glycol di(meth)acrylate monomer represented by the following gene
REFERENCES:
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patent: 5106998 (1992-04-01), Tanaka et al.
patent: 5130058 (1992-07-01), Tanaka et al.
patent: 5395566 (1995-03-01), Kobayakawa et al.
patent: 5449731 (1995-09-01), Suzuki et al.
Database WPI, Section Ch, Week 9349, Japanese Abstract, JP 05 295 358 A, Derwent Publications Ltd., London, GB; Class A89, AN 93-392954, Nov. 9, 1993.
Imura Satoshi
Kobayakawa Takashi
Nagoh Hironobu
Tokuyama Corporation
Tucker Philip
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