Easily dispersed alkali blue powder - prepd. by coprecipitating alkali blue and anionic dispersant, and adding hydrophobic phase

摘要

An anhydrous free-flowing alkali blue pigment is prepd. by coprecipitating alkali blue with =1 alkali sol. anionic dispersants contg. =8C and being water insol. in free acid form. The co-ppted. particles are then mixed with a hydrophobic oil phase to prevent hydrophilic aggregatin of the particles during subsequent drying. Used esp. for toning inks. The material is an easily dispersed powder, contg. a higher proportion of pigment than a flushing compsn. In an example 591 pts. alkali blue press cake (200pts dye) was dissolved in NaOH soln., and 14.7 pts. Turkey Red oil and 7.5 pts. GAFAC RS-610(RTM, Gaf.Corp) were added. Oil HCl was used to ppte. the dye. 41.1 pts. of a mixt. of 88% naphthnic mineral oil, 10% synth. Copal resin and 2% soya modified phthalic alkyd were added. Drying gave 250 pts. pigment contg. 76% dye.