Subpigmentary titanium dioxide with improved photostability

US5451252A · kind A · utility

Assignee

• Kronos, Inc. · US

Inventors

• Lothar Elfenthal · Bocholt, DE
• Rolf Schwindt · Leverkusen, DE
• Manfred Kluwig · Bad Honnef, DE

Key dates

• Filing date: Nov 3, 1994
• Grant date: Sep 19, 1995
• Expiry date: Nov 3, 2014

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01P2006/60
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

Subpigmentary titanium dioxide with decreased photoactivity is produced if known ions for increasing photostability in titanium dioxide pigments are not deposited on the surface of the subpigmentary particles, but instead are included intracrystallinely in the pigment particle (i.e., doped). In a preferred process for preparation of doped subpigmentary titanium dioxide particles, an acid solution containing the dopant is added in two stages to a suspension of subpigmentary titanium dioxide.