| 摘要 |
PURPOSE:To obtain the titled pigment which is excellent in adherability, extensibility, dispersibility, miscibility, ultraviolet absorbing properties, sunscreen-inhibiting effect, touch, safety to the skin, etc., by coating the surface of a pigment particle with a polyvalent metal salt of a specified acid. CONSTITUTION:A base pigment such as talc, kaolin or calcium carbonate is dispersed in an aq. soln. of 0.1-20wt% (based on the quantity of the pigment) water-soluble polyvalent metal salt of formula I (wherein M is Al, Mg, Zn, Ca, Zr; X is Cl, NO3, SO4, CH3COO; n is the valence of M). A 0.01-20wt%. aq. soln. of 1-4 equivalents (per equivalent of the polyvalent metal salt) of a p-methoxycinnamate of formula II (wherein M is Na, K, NH4) is added dropwise thereto. After the completion of the addition, the pH of the soln. is adjusted to an alkaline side and stirring is continued to deposit a polyvalent metal salt of p-methoxycinnamic acid of formula III on the surface of the pigment particle. The reaction mixture is filtered and the product is washed with water to completely remove deposited unreacted materials and dried, and if necessary, it is crushed. |
