| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | June 29, 1999 |
| PATENT TITLE |
Sunscreen concentrate |
| PATENT ABSTRACT |
A sunscreen concentrate in the form of a stable, uniform dispersion comprising, by weight: (a) about 30-65% of ultrafine titanium dioxide or zinc oxide, or mixtures thereof, (b) about 30-70% of an organic sunscreen agent, and (c) about 0.25-25% of a dispersing aid which is polyvinylpyrrolidone alkylated with a C.sub.4 -C.sub.36 alpha-olefin. |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | November 12, 1997 |
| PATENT CLAIMS |
What is claimed is: 1. A waterproof sunscreen concentrate in the form of a stable, homogeneous dispersion consisting essentially of, by weight: (a) about 30-65% of ultrafine titanium dioxide or zinc oxide, or mixtures thereof, (b) about 30-70% of an organic sunscreen agent, (c) about 0.25-25% of a dispersing aid which is a polyvinylpyrrolidone alkylated with a C.sub.4 -C.sub.36 alpha-olefin. 2. A sunscreen concentrate according to claim 1 which has a particle size of about 0.01-0.2.mu. (microns). 3. A sunscreen concentrate according to claim 1 which has a particle size of about 0.05-0.1.mu. (microns). 4. A sunscreen concentrate according to claim 1 which has a Brookfield viscosity of about 4,000 to 1,000,000 cps. 5. A sunscreen concentrate according to claim 1 which has a Brookfield viscosity of about 5,000 to 400,000 cps. 6. A sunscreen concentrate according to claim 1 wherein (c) is a hydrophilic polymer present in an amount of about 0.25-4%. 7. A sunscreen concentrate according to claim 6 wherein (c) is polyvinylpyrrolidone grafted with a C.sub.4 alpha-olefin and is present in an amount of about 0.5-2%. 8. A sunscreen concentrate according to claim 1 wherein (c) is a hydrophobic copolymer present in an amount of about 1-25%. 9. A sunscreen concentrate according to claim 1 wherein (c) is polyvinylpyrrolidone alkylated with a C.sub.16 -C.sub.19 alpha-olefin, and (c) is present in an amount of about 1-25%. 10. A sunscreen concentrate according to claim 1 wherein (c) is polyvinylpyrrolidone alkylated with a C.sub.20 -C.sub.30 alpha-olefin, and (c) is present in an amount of 5-25%. 11. A sunscreen concentrate according to claim 1 wherein (a) is present in an amount of 35-60%, (b) is 35-55% and (c) is 5-25%. 12. A sunscreen concentrate according to claim 1 wherein (a) is ultrafine titanium dioxide present in an amount of about 40%, (b) is about 59%, and (c) is a hydrophilic copolymer present in an amount of about 1%. 13. A sunscreen concentrate according to claim 1 wherein component (b) is one or more of the group consisting of oxybenzone(2-hydroxy-4-methoxybenzophenone); dioxybenzone(2,2'-dihydroxy-4-methoxybenzophenone); cinoxate(2-ethoxyethyl-p-methoxycinnamate); diethanolamine-p-methoxycinnamate; digalloyl trioleate ethyl 4-bis(hydroxypropyl)aminobenzoate; 2-ethylhexyl-2-cyano-3,3-diphenylacrylate; ethylhexyl-p-methoxycinnamate; 2-ethylhexyl salicylate; glyceryl aminobenzoate; homosalate(3,3,5-trimethylcyclohexyl salicylate); triethanolamine salicylate; 2-phenylbenzimidazole-5-sulfonic acid; sulisobenzone(2-hydroxy-4-methoxybenzophenone-5-sulfonic acid); Padimate A (amyl p-dimethylaminobenzoate); Padimate O (octyl dimethyl para aminobenzoate); 4-t-butyl-4'-methoxydibenzoylmethane; and the combination of 2-hydroxy-1,4-naphthoquinone with dihydroxyacetone; and menthyl anthranilate, and mixtures thereof; and octyl methoxycinnamate, octacrylene, octyl dimethyl-p-aminobenzoic acid, benzophenone and octyl salicylate, and mixtures thereof. 14. A sunscreen composition comprising the sunscreen concentrate of claim 1, water and optional adjuvants. 15. A sunscreen concentrate according to claim 1 wherein component (b) is ethylhexyl-p-methoxycinnamate. 16. A sunscreen composition according to claim 14 which provides a uniform distribution of component (a) over the skin of the user at different SPF values. -------------------------------------------------------------------------------- |
| PATENT DESCRIPTION |
BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a sunscreen composition, and, more particularly, to a stable, uniform dispersion of ultrafine titanium dioxide or zinc oxide in an organic sunscreen agent with polyvinylpyrrolidone alkylated with an alpha-olefin as a dispersing aid. 2. Description of the Prior Art Sunscreen compositions have been described extensively in the prior art. See, for example, U.S. Pat. Nos. 4,810,489; 4,820,508; 5,026,540; 5,041,281; 5,207,998; 5,219,559; 5,306,485; 5,445,815; 5,508,024; 5,599,529; and 5,603,863. Such compositions usually are formulated by admixing the several components in predetermined amounts. However, disadvantageously, such admixing often requires an elaborate sequence of addition of each of the components in expensive mixing equipment and order to assure a homogeneously dispersed composition. Accordingly, it is an object of this invention to provide a sunscreen concentrate in the form of a stable, homogeneous dispersion from which a sunscreen composition can be formed readily by simple dilution with a carrier. Another object of the invention is to provide a sunscreen concentrate comprising a stable, homogeneous dispersion of ultrafine titanium dioxide or zinc oxide, in an organic sunscreen agent, with polyvinylpyrrolidone alkylated with an alpha-olefin as a dispersing aid. Still another object herein is to provide a waterproofing sunscreen concentrate having both an inorganic sunblock agent and a UV-absorbing organic sunscreen agent therein, in a hydrophilic or hydrophobic copolymer of polyvinylpyrrolidone and an alpha-olefin, wherein the particle size (u, microns) of the concentrate is about 0.01-0.2.mu., preferably about 0.05-0.1.mu., and a Brookfield viscosity of about 4,000 to 1,000,000 cps, preferably about 5,000 to 400,000 cps. These and other objects and features of the invention will be made apparent from the following more detailed description of the invention. SUMMARY OF THE INVENTION What is described herein is a waterproofing sunscreen concentrate in the form of a stable, uniform dispersion comprising, by weight: (a) about 30-65% of ultrafine titanium dioxide or zinc oxide, or mixtures thereof, (b) about 30-70% of an organic sunscreen agent, and (c) about 0.25-25% of a dispersing aid which is polyvinylpyrrolidone alkylated with a C.sub.4 -C.sub.36 alpha-olefin. Suitably, the particle size of the concentrate is about 0.01-0.2.mu., preferably about 0.05-0.1.mu.; and the Brookfield viscosity is about 4,000 to 1,000,000 cps, preferably 5,000 to 400,000 cps. Commercial sunscreen compositions may be prepared easily by mixing the sunscreen concentrate of the invention with water and other conventional ingredients of such compositions. DETAILED DESCRIPTION OF THE INVENTION The waterproofing sunscreen concentrate of the invention includes a sunblock component (a) which is ultrafine titaniumn dioxide or zinc oxide, present in an amount of about 30-65% by weight of the concentrate. Ultrafine titanium dioxide is preferred. The sunscreen concentrate of the invention also includes an UV-absorbing sunscreen agent which is the active component (b). Suitable organic sunscreen agents include cinoxate(2-ethoxyethyl-p-methoxycinnamate); diethanolamine-p-methoxycinnamate; digalloyl trioleate ethyl 4-bis(hydroxypropyl)aminobenzoate; ethylhexyl-p-methoxy-cinnamate; 2-ethylhexyl salicylate; glyceryl aminobenzoate; homosalate(3,3,5-trimethylcyclohexyl salicylate); triethanolamine salicylate; 2-phenyl-benzimidazole-5-sulfonic acid; sulisobenzone(2-hydroxy-4-methoxybenzophenone-5-sulfonic acid); Padimate A (amyl p-dimethylaminobenzoate); Padimate O (octyl dimethyl para aminobenzoate); and menthyl anthranilate, and mixtures thereof. The sunscreen agents also may include a sunscreen material particulary suitable for ultraviolet-A (320-400 nm) protection. This compound suitably is selected from oxybenzone, dioxybenzone; 2-ethylhexyl-2-cyano-3,3 diphenylacrylate; methyl benzilidine camphor; 4-t-butyl-4'-methoxydibenzoyl-methane and mixtures thereof. The total amount of organic sunscreen agent suitably is present in an amount ranging from about 30% to 70%, preferably about 35-55%, by weight of the total concentrate. Component (c) of the sunscreen concentrate of the invention is a dispersing aid to provide the concentrate as a stable uniform dispersion. The dispersing aid herein is polyvinylpyrrolidone (PVP) alkylated with a C.sub.4 -C.sub.36 alpha-olefin; suitably present in an amount of about 0.25 to 25% by weight of the concentrate. Component (c) may be a hydrophilic or hydrophobic polymer. A hydrophilic copolymer is made by grafting a C.sub.4 alpha-olefin upon the PVP; it is sold by International Specialty Products Inc. (ISP), as Ganex.RTM. P-904LC and P-904. The hydrophilic copolymer suitably is present in the concentrate in an amount of about 0.25-4%, preferably about 0.5-2%, by weight of the concentrate. Hydrophobic copolymers are made by grafting a C.sub.16 to C.sub.36 alpha-olefin upon PVP. These hydrophobic copolymers also are available from ISP as Ganex.RTM. V-216, a liquid, or Ganex.RTM. V-220 and WP 660, which are available in the form of waxy solids or flakes. Ganex.RTM. V-216 suitably is present in the concentrate in an amount of about 0.25-25%, and optimally 5-20%, while Ganex.RTM. V-220 suitably is present in an amount of about 5-25%, preferably 10-20%. A preferred hydrophobic copolymer is Ganex.RTM. V-216. A C.sub.20 alpha-olefin containing copolymer preferably is present in an amount of about 5-25%. The sunscreen concentrate of the invention may be formed by simply mixing components (a), (b) and (c), using conventional, inexpensive agitation equipment. The sunscreen concentrate thus formed is a stable, homogeneous dispersion of an inorganic sunblock, an organic sunscreen agent, and a Ganex.RTM. dispersion aid, having a particle size of about 0.01-0.2.mu., preferably 0.05-0.1.mu., and a Brookfield viscosity of 4,000 to 1,000,000 cps, preferably about 5,000 to 400,000 cps. Thereafter, upon simple dilution of the sunscreen concentrate with an appropriate carrier, and other adjuvants, if desired, an end-use broad spectrum waterproofing sunscreen composition can be readily prepared which can provide a uniform distribution of active sunblock and sunscreen agents upon the skin of the user at selected SPF values. |
| PATENT EXAMPLES | available on request |
| PATENT PHOTOCOPY | available on request |
|
Want more information ? Interested in the hidden information ? Click here and do your request. |