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US 8,137,659 B2Granted
Metal oxide composition
AssigneeCroda International PLC
InventorLoma Margaret Kessell
Life of this patent
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Abstract
A composition comprises a non-ionic surfactant and hydrophobic particles of metal oxide having the mean length of the primary particles in the range from 50 to 90 nm, the mean width of the primary particles in the range from 5 to 20 nm, and the median volume particle diameter of the secondary particles is less than 45 nm. The composition is particularly suitable for use in aqueous media, and can be used in a sunscreen product that exhibits both effective UV protection and improved transparency.
Claims26
An aqueous dispersion, comprising:
- i) at least one non-ionic surfactant having an HLB value in the range from 5 to 20;
- and
- ii) hydrophobic particles of metal oxide having:
- a) primary particles having a mean length in the range from 50 to 90 nm and a mean width in the range from 5 to 20 nm;
- b) secondary particles, comprising clusters or agglomerates of the primary particles, having a median particle volume diameter of less than 45 nm;
- c) an extinction coefficient at 524 nm (E524) of less than 2.0 l/g/cm;
- and
- d) an extinction coefficient at 308 nm (E308) of greater than 30 l/g/cm.
5 more elements
Dependencies are inferred from the claim text.