PURPOSE: To obtain a brown-based colorant having improved weather resistance and heat resistance, by suspending vinyl chloride resin in an alkali aqueous solution of a humate, blending them, dehydrating the blend while blending it at ≥specific temperature with stirring.
CONSTITUTION: First, 5W20wt% alkali aqueous solution of a humate and/or its derivative slat is prepared, and the aqueous solution is adjusted to preferably 9W10pH. Preferably 250W2,000pts.wt. vinyl chloride resin(preferably non-rigid straight polymer having about 700W1,300 polymerization degree) is added to 100pts.wt. humate, blended under heating at ≥40°C for 5W30min with stirring, so that the vinyl chloride resin is fully dispersed. The suspension is heated in a mixer, blended at ≥80°C preferably for 30W40min, and water is evaporated to give powder. The powder is further subjected to hot-air drying.
SAKURAI HIDETAKE
KOBAYASHI TOMEGOROU
