Back to results
US 5,516,457 AGranted
Oil-in-water emulsions
AssigneeTioxide Specialties Limited
InventorGerd H. Dahms
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeTioxide Specialties Limited
InventorGerd H. Dahms
Estimating the term…
An oil-in-water emulsion containing 0.5% to 30% metallic oxides having a particle size of less than 0.2 micron, less than 10% total emulsifier, 5% to 30% of an oil phase and at least 60% of an aqueous phase is provided. The invention also makes available a method of preparing such emulsions in which the emulsion is formed by use of a dispersion in water of the metallic oxide particles. By comparison with previously known emulsions of this type relatively small quantities of emulsifiers are used and it is possible to use an emulsion system with a low HLB value (e.g. less than 6). Preferably no hydrophilic emulsifiers are used. The emulsions are suitable for preparing UV-absorbing compositions such as sunscreens, moisturisers and after-sun lotions. The ability to use no, or little, hydrophilic emulsifiers is advantageous since, in, general, these emulsifiers are not biodegradable whereas hydrophobic emulsifiers generally are biodegradable.
An oil-in-water emulsion comprising from 0.5 per cent to 30 percent by weight with respect to the total weight of emulsion of particles of a metallic oxide having an average primary particle size of less than 0.2 micron, said emulsion containing an emulsifier system comprising one or more emulsifiers, said emulsifier system being present in an amount of less than 10 per cent by weight with respect to the total weight of emulsion and having a hydrophile-lipophile balance of less than 6, from 5 per cent to 30 per cent by weight with respect to the total weight of emulsion of an oil phase, at least 60 per cent by weight with respect to total weight of emulsion of an aqueous phase and isoamyl p-methoxycinnamate.
A process for preparing an oil-in-water emulsion comprising forming an aqueous dispersion of particles of a metal oxide having an average primary particle size of less than 0.2 micron and mixing said dispersion with an emulsifier system comprising one or more emulsifiers, an oil phase and isoamyl p-methoxycinnamate under conditions in which an oil-in-water emulsion is formed wherein the total amount of emulsifiers present in the oil-in-water emulsion so formed is less than 10 per cent by weight and the emulsifier system has a hydrophile-lipophile balance of less than 6, the particles of metallic oxide comprise from 0.5 per cent to 30 per cent by weight of the emulsion, the oil phase comprises 5 per cent to 30 per cent by weight of the emulsion, the oil phase comprises 5 per cent to 30 per cent by weight of the emulsion and an aqueous phase comprises at least 60 per cent by weight of the emulsion.
A process for preparing an oil-in-water emulsion comprising forming an aqueous dispersion of particles of a metallic oxide having an average primary particle size of less than 0.2 micron and mixing said dispersion with one or more emulsifiers, an oil phase and isoamyl p-methoxycinnamate under conditions in which an oil-in-water emulsion is formed wherein the total amount of emulsifiers present in the oil-in-water emulsion so formed is less than 5 per cent by weight, the particles of metallic oxide comprise from 0.5 per cent to 30 per cent by weight of the emulsion, the oil phase comprises 5 per cent to 30 per cent by weight of the emulsion and an aqueous phase comprises at least 60 per cent by weight of the emulsion.
Dependencies are inferred from the claim text.