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Subpigmentary titanium dioxide with improved photostability

  • US 5,451,252 A
  • Filed: 11/03/1994
  • Issued: 09/19/1995
  • Est. Priority Date: 07/11/1992
  • Status: Expired due to Fees
First Claim
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1. A process for preparing metal ion-doped subpigmentary titanium dioxide particles having improved photostability wherein the metal ion-dopant is homogeneously intracrystalline-distributed internally in the subpigmentary titanium dioxide particles, said process comprising the steps of:

  • (a) providing a suspension of subpigmentary titanium dioxide;

    (b) introducing a first portion of a metal ion-dopant into the suspension;

    (c) maturing the suspension for a first period of time;

    (d) introducing the remainder of the metal ion-dopant into the suspension;

    (e) maturing said suspension for a second period of time;

    (f) recovering subpigmentary titanium dioxide from said suspension;

    thereby producing metal ion-doped subpigmentary titanium dioxide particles with the dopant distributed intracrystallinely throughout the particles.

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