Browse Prior Art Database

Publication Date: 2003-Apr-11
Document File: 12 page(s) / 72K

Publishing Venue

The Prior Art Database


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.

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Background of the Invention

        � � � � � � � � � � � The present invention relates to a process for preparing a cosmetic formulation and to a cosmetic formulation composition.� More particularly, the present invention relates to a process for preparing a cosmetic formulation and to a cosmetic formulation composition utilizing a high internal phase ratio (HIPR) emollient-in-water emulsion for example wherein the emollient of the emulsion may be a silicone elastomer or a suncreen agent.

Historically, cosmetic formulations have been prepared by emulsifying an oil phase with an aqueous phase matrix using a batch process wherein the oil and water mixture is sheared in a large vessel.� The oil phase typically includes a mixture of complex and varying oil-miscible ingredients and, consequently, batch-to-batch reproducibility of oil droplet size is often elusive.� Moreover, processing time can be quite long and scale-up of the process from the benchtop to the manufacturing plant can be frustrating because tank-based processes often do not scale up in a linear fashion.

        � � � � � � � � � � � In WO 01/54663, Wilmott et al. discloses a possible solution to the problems associated with formulating personal care products by providing a substantially surfactant-free stable aqueous dispersion (that is, stable for at least two months), containing up to 70%, more preferably up to 50%, by weight of an oil phase, to which active ingredients can be added.� This approach allows simple mixing of all ingredients, without the need for sub-phases or any special processing, to create a formulated cosmetic product.� Nevertheless, there still remains an ever-increasing need to offer formulators more flexibility in controlling and fine tuning the properties of the final product, and to allow the formulators to use dispersions at their convenience.

For example, although there are various known processes for making sunscreens, there is still a need to make an unencapsulated sunscreen agent emulsion with an improved sun protection factor (SPF).�

Organic sunscreen emulsions with particle size of less than 2 microns are known in the art where in the organic sunscreen is encapsulated and the effective sun protection factor is improved with respect to conventional formulations (Duncan Aust, “Sunscreen SPF Enhanced By Nano-Dispersion Technology –Study,” Rose Sheet, June 4, 2001).� Unencapsulated organic sunscreens of small size are known by templating on solid disperse polymers (U.S. Patent No. 6,216,948) or Pickering emulsions (U.S. Patent Publication No. 20020160030).� Dispersions of solid organic sunscreens less than 2 microns have been made by grinding (micronizing) the solid sunscreen (U.S. Patent No. 5,980,872).� The use of an effective amount of a surfactant for making unencapsulated organic sunscreen emulsions less than 2 microns is not known.�

        � � � � � � � � � � � As one objective of the presen...