| 摘要 |
<p>Agent is prepd. from pigment and dispersion agent-binder which has been obtd., as ex colloid, by adding a mixt. of phosphoric acid and an ammonium base (sic, cpd. furnishing NH4+) to a starch, reacting these three in an autoclave at 160-220 deg.C for 180-240 minutes, quenching the mixt. rapidly to below 45 deg.C dispersing, hydrating, and drying at temp. above 80 deg.C. Pref. Ca ion-contg. pigment, partic. CaSO4, is added to an aq. soln. of the colloid at below 45 deg.C and mixt. is dispersed for more than 45 minutes. Mixt. contains pigment, partic. A1(OH)3, of particle size 1-6 microns. Ammonium base is urea, starch is potato starch. Colloid is formed from 1-20% phosphoric acid, 1-50% ammonium base, and remainder starch. Ammonium base is added to aq. soln. of the colloid to establish a basic pH.</p> |
