Method for improving light-fastness of reversible thermochromic compositions at the time of color development

摘要

A method of causing metachromatism by the use of a reversible thermochromic composition comprising (a) an electron donating compound, (b) an electron accepting compound and (c) a metachromatic temperature adjuster, wherein; (d) an electron accepting, light-fastness providing agent represented by Formula I: <IMAGE> wherein n represents an integer of 5 to 17 to form a straight-chain or branched alkyl group; X and Y each represent a straight-chain or branched alkyl group having 1 to 4 carbon atoms, or a halogen atom; and p and m each represent an integer of 0 to 3; is brought into presence in an amount of 0.3 part by weight to 70 parts by weight based on 1.0 part by weight of the component-(a) electron donating compound. The light-fastness of the reversible thermochromic composition at the time of color development can be greatly improved.