Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1997-11-26
1999-07-13
Richter, Johann
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
548255, 548257, C07D24918
Patent
active
059228822
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to novel bisbenzotriazolylphenol compounds and copolymers containing the compound as a copolymerization component.
PRIOR ART
2-Hydroxyphenylbenzotriazole compounds are known as UV absorbers useful for protecting plastics from UV rays. However, most of the known UV absorbers are low-molecular compounds which cause a number of problems. For example, conventional benzotriazole-based UV absorbers have high vapor pressures because of their low molecular weights, and are known to transpire when blended with a resin and subjected to a molding process, polluting working environment and staining the mold. Further, conventional UV absorbers are of addition type and used as merely mixed with the base resin. Therefore, they tend to bleed out of the obtained molded article or coating film with the lapse of time, or are washed out by rain or detergent-containing water in using environment, failing to impart light stability to the product for a long period.
Some methods have been proposed in which the conventional low-molecular weight compounds used as UV absorbers are converted into high-molecular compounds to solve the above problems.
For example, Japanese Examined Patent Publiation No. 25036/1963 and Japanese Unexamined Patent Publications Nos. 51181/1985 and 112062/1986 disclose high-molecular UV absorbers obtained from polymerizable benzotriazole compounds. However, these compounds can be used only in the form of copolymers with addition polymerizable monomers, and cannot be used for polymers produced by polycondensation.
Japanese Unexamined Patent Publications Nos. 188581/1990 and 200788/1991 disclose condensation polymerizable benzotriazole compounds having a plurality of carboxyl groups in the molecule. However, as apparent from their structures, these compounds, although usable in the production of polyesters or polyamides, cannot be employed in the production of polycarbonates or polyurethanes which are particularly susceptible to deterioration by UV rays.
Further, Japanese Examined Patent Publication No. 20913/1992 discloses benzotriazole and bisbenzotriazole compounds having a plurality of hydroxyalkyl groups. However, since the hydroxyalkyl groups are introduced into the compounds through ester bonds, these compounds undergo hydrolysis or ester exchange when used as comonomers in polycondensation. These reactions can cause troubles especially in polymerization under alkaline conditions or in polyester production requiring high temperature polymerization. In addition, carboxyl- or ester-containing benzotriazole compounds are produced as by-products and act as stoppers, preventing the rise in the polymerization degree.
Further, Japanese Examined Patent Publication No. 39180/1980 discloses dimerized benzotriazole compounds, and Japanese Unexamined Patent Publication No. 39326/1991 teaches weather-resistant polycarbonates prepared using the dimerized compound as a copolymerization monomer. However, when the dimerized compound is used as the copolymerization monomer of the polycarbonate, phenolic hydroxyl groups, which are essential functional groups for imparting UV absorptivity, inevitably participate in the copolymerization and are lost. As a result, the obtained polycarbonate has insufficient light resistance.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a novel bisbenzotriazolylphenol compound useful as an UV absorber, the compound having good UV absorptivity, very low vapor pressure and high heat stability.
Another object of the present invention is to provide a bisbenzotriazolylphenol compound which does not transpire even when blended with a resin requiring high molding temperature (e.g., engineering plastics) and subjected to a melt-molding process.
A further object of the present invention is to provide a copolymer comprising the bisbenzotriazolylphenol compound as a copolymerization component.
Other features of the present invention will be apparent from the following description.
The bisbenzotriazolylphenol com
Akada Mitsuo
Daimon Emiko
Ishida Koji
Kawano Kazuhiro
Mori Koji
Otsuka Kagaku Kabushiki Kaisha
Richter Johann
Sackey Ebenezer
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