Enhanced efficiency of sunscreen compositions
Compositions comprising UV blocking agents, a film forming polymer containing acid groups and a neutralizing agent; compositions and methods for increasing the SPF of a composition by neutralizing at least a portion of the acid groups of the film forming agent with the neutralizing agent.
1. A method for increasing the SPF of a composition that comprises at least one sunscreen active agent, less than about 5% by weight of water and, in a concentration greater than 1% by weight of the final composition, acrylates/octylacrylamide copolymer comprising a plurality of carboxylic acid groups, wherein the method comprises neutralizing at least 25% and up to 80% of the plurality of carboxylic acid groups exclusively with an amine-based neutralizing agent which is selected from alkyl amines; alkenyl amines; dialkyl amines; dialkenyl amines; dimethyl alkyl amines, wherein alkyl is stearyl or cocoyl; methyl dialkyl amines, wherein alkyl is stearyl or hexadecyl; and dimethyl alkenyl amines, wherein alkenyl is oleic, linoleic or linolenic, the acrylates/octylacrylamide copolymer being the only polymer present in the composition.
2. The method of claim 1 , wherein the amine-based neutralizing agent comprises dimethyl stearyl amine.
3. The method of claim 1 , wherein the acrylates/octylacrylamide copolymer is present in a concentration of up to 10% by weight of the final composition.
4. The method of claim 1 , wherein the acrylates/octylacrylamide copolymer is present in a concentration of up to 5% by weight of the final composition.
5. The method of claim 1 , wherein up to 70% of the plurality of acid groups are neutralized by the amine-based neutralizing agent.
6. The method of claim 1 , wherein at least 50% of the plurality of acid groups are neutralized by the amine-based neutralizing agent.
7. The method of claim 1 , wherein neutralizing the carboxylic acid groups of the acrylates/octylacrylamide copolymer with the amine-based neutralizing agent results in an SPF rating which is greater than 1.5 times the SPF rating of the composition without neutralized carboxylic acid groups.
8. The method of claim 1 , wherein neutralizing the carboxylic acid groups of the acrylates/octylacrylamide copolymer with the amine-based neutralizing agent results in an SPF rating which is greater than 2 times the SPF rating of the composition without neutralized carboxylic acid groups.
9. The method of claim 1 , wherein the composition exhibits a sun protection factor (SPF) of at least 50.
10. The method of claim 1 , wherein the composition comprises less than about 1% by weight of water.
11. The method of claim 1 , wherein the composition is sprayable.
12. A method for increasing the SPF of a composition that comprises at least one sunscreen active agent, less than about 1% by weight of water and, in a concentration greater than 1% by weight of the final composition, acrylates/octylacrylamide copolymer comprising a plurality of carboxylic acid groups, wherein the method comprises neutralizing at least 40% and up to 70% of the plurality of carboxylic acid groups exclusively with an amine-based neutralizing agent which is selected from dimethyl alkyl amines wherein alkyl is stearyl or hexadecyl, the acrylates/octylacrylamide copolymer being the only polymer present in the composition.
13. The method of claim 12 , wherein the amine-based neutralizing agent is dimethyl stearyl amine.
14. The method of claim 12 , wherein the acrylates/octylacrylamide copolymer is present in a concentration of up to 5% by weight of the final composition.
15. The method of claim 12 , wherein neutralizing the carboxylic acid groups of the acrylates/octylacrylamide copolymer with the amine-based neutralizing agent results in an SPF rating which is greater than 1.5 times the SPF rating of the composition without neutralized carboxylic acid groups.
16. The method of claim 12 , wherein the composition is sprayable.
17. A method for increasing the SPF of a sprayable composition that comprises at least one sunscreen active agent, less than about 1% by weight of water and, in a concentration greater than 1% and up to 5% by weight of the final composition, acrylates/octylacrylamide copolymer comprising a plurality of carboxylic acid groups, wherein the method comprises neutralizing at least 25% and up to 80% of the plurality of carboxylic acid groups with dimethyl stearyl amine, which results in an SPF rating that is greater than 1.5 times the SPF rating of the composition without neutralized carboxylic acid groups, the acrylates/octylacrylamide copolymer being the only polymer present in the composition.