反应详情

100 parts of 3-cyclohexyl-5-(α,α-dimethylbenzyl) salicylic acid was mixed by the use of Nauta mixer (manufactured by HOSOKAWA TEKKOSHO, Japan) with 500 parts of zinc carbonate and 100 parts of α-methylstyrene-styrene copolymer which was obtained by the polymerization of 60% α-methylstyrene with 40% styrene and had a molecular weight of about 2,000. The water content of the resultant mixture was 1.2%. 250 parts of water containing 5% ethyl alcohol was added in the mixture and the mixture was heated at 150° C. for 15 minutes with stirring. Then the mixture was cooled to a room temperature to form a solid mass. The mass was pulverized by a hammer mill to obtain finely divided particles, 80% of which was passed through 250 mesh Tyler standard screen. The obtained color developer contained 1.5% water on the total dry basis.