Sunscreen composition and a process for preparing it
View Patent ↗The present invention includes a process of preparing an advanced cosmetic product by combining a high internal phase ratio (HIPR) emollient-in-water emulsion with a partial cosmetic formulation that typically contains water, a coloring agent, a fragrance, a rheology modifier, or a pH adjuster, or a combination thereof. The present invention also includes compositions directed to two particular subclasses of HIPR emollient-in-water emulsions, namely an HIPR silicone elastomer-in-water emulsion and an HIPR sunscreen-in-water emulsion and water-diluted dispersions thereof. The use of an HIPR emulsion of a cosmetic emollient provides a simple and flexible method of formulating the cosmetic product, due in part to the long shelf-stability of the HIPR emulsion (greater than 1 year), and the low quantity of water in the emulsion (typically less than 20% by volume based on the volume of emollient and water). The HIPR sunscreen-in-water emulsion can be formulated into an advanced cosmetic product with an improved sun protection factor (SPF) and critical wavelength.
1. A sunscreen composition comprising:
A. an unencapsulated emollient-in-water emulsion containing water and at least one emollient, wherein the emollient of said emulsion contains at least one organic sunscreen agent, and wherein the sunscreen agent-containing emollient has a volume mean particle size of less than about 3 microns and the content of the sunscreen agent-containing emollient is at least 55% by weight, based on the weight of the water and the emollient; and
B. an effective amount of an emulsifying surfactant to decrease the interfacial tension between water and the sunscreen agent.
2. A composition of claim 1 wherein the sunscreen agent-containing emollient has a volume mean particle size of less than about 2 microns.
3. A composition of claim 1 wherein the sunscreen agent-containing emollient has a particle size of less than about 1 micron.
4. A composition of claim 1 wherein the surfactant is anionic, nonionic or zwitterionic.
5. A composition of claim 1 wherein the sunscreen agent includes 2-ethylhexyl-4-methoxycinnamate.
6. A composition of claim 1 wherein the sunscreen agent includes octyl salicylate.
7. A composition of claim 1 wherein the sunscreen agent includes 2-ethylhexyl-4-methoxycinnamate and octyl salicylate.
8. A composition of claim 1 wherein the composition provides a sun protection factor (SPF) increase of at least about 20 percent when compared to a same sunscreen composition having Components A and B except that Component A contains a sunscreen agent-containing emollient having a volume mean particle of size greater than 3 microns.
9. A composition of claim 1 wherein the composition exhibits a critical wavelength increase of at least about 10 nm when compared to a same sunscreen composition having Components A and B except that Component A contains a sunscreen agent-containing emollient having a volume mean particle size greater than 3 microns.
10. A composition of claim 1 wherein the surfactant is selected from the group consisting of potassium cetyl phosphate, polyoxyethylene (20) sorbitan monostearate, 1,2,4-benzenetricarboxyic acid, tris(decyl) ester or any combination thereof.
11. A composition of claim 1 including an SPF enhancement additive, said SPF enhancement additive being different from the other components in the composition.
12. A composition of claim 1 including a UVA enhancement additive or a UVA booster, said UVA enhancement additive or UVA booster being different from the other components in the composition.
13. A process for preparing a sunscreen composition comprising mixing:
A. an unencapsulated emollient-in-water emulsion, wherein the emollient contains at least one organic sunscreen agent, and wherein the sunscreen agent-containing emollient has a volume mean particle size of less than about 3 microns and the content of the sunscreen agent-containing emollient is at least 55% by weight, based on the weight of the water and the emollient; and
B. an effective amount of an emulsifying surfactant to decrease the interfacial tension between water and the sunscreen agent.