The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 07, 1995
Filed:
Mar. 02, 1993
Takashi Kobayakawa, Tokuyama, JP;
Satoshi Imura, Tokuyama, JP;
Kazumasa Itonaga, Tokuyama, JP;
Kazuhiko Kuramoto, Tokuyama, JP;
Tokuyama Corporation, Tokuyama, JP;
Abstract
A photochromic composition comprising (A) 100 parts by weight of a compound having at least one epoxy group in the molecule and (B) 0.0001 to 10,000 parts by weight of a photochromic compound. The compound (A) is represented by the following general formula ##STR1## wherein A is a residue of an n-valent alcoholic hydroxyl-containing compound, a residue of an n-valent phenolic-hydroxyl-containing compound, or a residue of an n-valent carboxylic acid, R.sup.1 is a hydrogen atom or a methyl group, and n is an integer of 1 to 4. Examples of the (A) compound include alcoholic hydroxyl-containing compounds such as monohydric, dihydric or trihydric alcohols, reaction products of phenolic hydroxyl-containing compounds such as phenol or hydroquinone with epichlorohydrin, or reaction products of carboxylic acids such as benzoic acid, or terephthalic acid with epichlorohydrin. Examples of the (B) photochromic compound include fulgide compounds, spirooxazine compounds and chromene compounds. A polymer obtained by polymerizing the above photochromic composition of the invention by a radical polymerization method has a good durability of photochromic properties, and also possesses a dark color-forming density, a fast color fading speed, is transparent, and has a high surface hardness. Thus, especially, the polymer is suitable for use as a photochromic lens.