DRY C.I. PIGMENT RED 57:1, DRY PIGMENT COMPOSITION AND METHOD FOR PRODUCING THEM

摘要

A dry C.I. pigment red 57:1 which has a BET specific surface area of 60 to 110 m<2>/g, as measured by the nitrogen adsorption method, and a total volume of the pores having a pore diameter in the range of 0.1 to 3.0 mum of 1.30 to 2.00 ml/g, as measured by the mercury porosimetry; a dry pigment composition comprising a rosin and C.I. pigment red 57:1; and a method for producing the dry C.I. pigment red 57:1 which comprises adding an aqueous solution or the like containing a water-soluble salt of 2-(3-carboxy-2-hydroxynaphthylazo)-5-methylbenzenesulfonic acid to an aqueous solution containing an inorganic calcium compound in an amount sufficient for converting all of the above water-soluble salt to a calcium salt, to thereby effect the formation of a lake, followed by aging, filtration and then drying.