Surface-modified silicon dioxide-titanium dioxide mixed oxides
AssigneeDegussa AG
InventorsJürgen Meyer, Kai Schumacher, Steffen Hasenzahl, Heike Riedemann, Ann Gray
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Abstract
Pyrogenically prepared surface-modified silicon dioxide-titanium dioxide mixed oxides are prepared by spraying pyrogenically prepared silicon dioxide-titanium dioxide mixed oxides with a surface-modifying agent. The surface-modified pyrogenically prepared silicon dioxide-titanium dioxide mixed oxides can be used in sun protection formulation.
Claims17
Pyrogenically prepared surface-modified silicon dioxide-titanium dioxide mixed oxides produced by a process comprising modifying the surface of pyrogenically prepared silicon dioxide-titanium dioxide mixed oxides with a silica or organosilane surface-modifying agent of formula I or a silane formed by the partial hydrolysis and condensation of an organosilane of formula I:
- Si(OR)x(OR′)y(OR″)u(OR′″)v (I)
- wherein:
- x=0,1,2,3,4
- y=0,1,2,3,4
- u=0,1,2,3,4
- v=0,1,2,3,4
- x+y+u+v=4 and
- R, R′, R″ and R′″ are each independently a C1-C6 alkyl.
A process for the preparation of a pyrogenically prepared, surface-modified silicon dioxide-titanium dioxide mixed oxides, comprising:
- a) treating pyrogenically prepared silicon dioxide-titanium dioxide mixed oxides with a surface-modifying agent in vapour form and
- b) heat treating the pyrogenically prepared silicon dioxide-titanium dioxide mixed oxides that have been surface modified in step a)
- wherein said surface modifying agent comprises a silica or organosilane surface-modifying agent of formula I or a silane formed by the partial hydrolysis and condensation of an organosilane of formula I:
- Si(OR)x(OR′)y(OR″)u(OR′″)v (I)
- wherein:
- x=0,1,2,3,4
- y=0,1,2,3,4
- u=0,1,2,3,4
- v=0,1,2,3,4
- x+y+u+v=4 and
- R, R′, R″ and R′″ are each independently a C1-C6 alkyl.
Dependencies are inferred from the claim text.