BROWN OR GREY SEALED PIGMENT AND PREPARATION THEREOF

摘要

Inclusion pigments (I) are based on Zr silicate (II) as shell substance, in which coloured cpds. (Fe1-xMnx)2O3 of formula (III) are enclosed as discrete phase and are mixed crystals. In (III) x is 0.05-0.60. Pref. (Fe,Mn) zeolites are used as (III). Esp. x is 0.05-0.20 or 0.30-0.60. (I) are prepd. by calcining a mixt. of ZrO2 and SiO2 or their precursors in 1:1 molar ratio for 0.5-8 hrs. at 750-1200 deg.C in the presence of mineralisers and Fe and Mn cpds. or cpds. contg. Fe and Mn with an Fe/Mn atomic ratio of 90:10 to 20:80. Pref. calcination temp. is 850-1000 deg.C for an Fe/Mn ratio of 50:50-80:20 and 1050-1200 deg.C for an Fe/Mn ratio of 50:50-30:70. Unincluded Mn and Fe cpds. are removed by treating the calcined prod. with acid.