| 摘要 |
THE INVENTION RELATES TO A METHOD FOR THE POST-TREATMENT OF TITANIUM DIOXIDE, IN ORDER TO PRODUCE PARTICULARLY WEATHER-RESISTANT TITANIUM DIOXIDE PIGMENTS WITH GOOD OPTICAL PROPERTIES. THE METHOD IS CHARACTERISED IN THAT, TOGETHER WITH THE HYDROUS OXIDES OF TIN AND ZIRCONIUM, AT LEAST ONE OTHER FROM THE GROUP COMPRISING ALUMINIUM, SILICON AND TITANIUM IS ADDITIONALLY PRECIPITATED ONTO THE PARTICLE SURFACE. THE POST-TREATMENT COMPONENTS ARE ADDED TO THE AQUEOUS TIO₂ SUSPENSION EITHER IN THE ACIDIC RANGE (PH VALUE OF 3 AT MOST) OR IN THE ALKALINE RANGE (PH VALUE OF 10 AT LEAST). THE PH VALUE IS SUBSEQUENTLY SET TO BETWEEN 6 AND 8. FINAL TEMPERING OF THE PIGMENT AT ELEVATED TEMPERATURES FROM OVER 125 ˚C TO UP TO 500˚C CAN IMPROVE THE TONE B. THE PIGMENT IS PARTICULARLY SUITABLE FOR USE IN PAINTS, COATINGS AND PLASTICS.
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