Biodegradable polyesters for water-resistant water-in-oil suncare formulations
The present disclosure generally relates to a waterproofing polymer that is a reaction product of the following components: (i) at least one polyglycerol; (ii) at least one dimer acid; and (iii) at least one fatty acid having 8-30 carbon atoms, wherein (iii) and (i) are in a molar ratio of less than 2:1. The components are charged to a reaction vessel and subsequently reacted to produce a polyester polymer having excellent waterproofing properties. The polymers impart high static and water-resistant SPF to water-in-oil sunscreen formulations.
1 . A water-in-oil formulation comprising from 1 to 5 weight percent actives of a waterproofing polymer based on a total weight of the formulation, wherein the waterproofing polymer is a reaction product of:
(i) a polyglycerol comprising a combination of diglycerol, triglycerol, tetraglycerol, pentaglycerol, hexaglycerol, heptaglycerol, and octaglycerol;
(ii) a hydrogenated C36 dimer acid; and
(iii) isostearic acid;
wherein (i), (ii) and (iii) are reacted in a molar ratio of 1:0.5:1.
2 . The formulation according to claim 1 , wherein the waterproofing polymer is a completely non-sequential reaction product.
3 . The formulation according to claim 1 , wherein the polyglycerol comprises at least 40% by weight, based on a total weight of the polyglycerol, of a combination of diglycerol and triglycerol.
4 . A water-in-oil sunscreen formulation comprising:
(a) a sunscreen active agent;
(b) from 1 to 5 weight percent actives of a waterproofing polymer based on a total weight of the formulation, wherein the waterproofing polymer is a reaction product of:
(i) a polyglycerol comprising a combination of diglycerol, triglycerol, tetraglycerol, pentaglycerol, hexaglycerol, heptaglycerol, and octaglycerol;
(ii) a hydrogenated C36 dimer acid; and
(iii) isostearic acid;
wherein (i), (ii) and (iii) are reacted in a molar ratio of 1:0.5:1; and
(c) an emollient.
5 . The formulation according to claim 4 , wherein the waterproofing polymer is a completely non-sequential reaction product.
6 . The formulation according to claim 4 , wherein the polyglycerol comprises at least 40% by weight, based on a total weight of the polyglycerol, of a combination of diglycerol and triglycerol.
7 . The sunscreen formulation according to claim 4 , which further comprises at least one water-in-oil emulsifier chosen from tripolyglyceryl-3/lauryl hydrogenated trilinoleate, polyglyceryl-4 isostearate, cetyl PEG/PPG-10/1 dimethicone, hexyl laurate, cetyl PEG/PPG-10/1 dimethicone, cetyl PEG/PPG-10/1, dimethicone and hexyl laurate and olyglyceryl-4 isostearate, PEG-30 dipolyhydroxystearate, and polyglyceryl-3 polyricinoleate, and combinations thereof.
8 . A method of protecting a user from damaging effects of sunlight, said method comprising applying to skin of said user an effective amount of the sunscreen formulation according to claim 4 .
9 . A method of forming the water-in-oil sunscreen formulation of claim 4 , said method comprising the step of combining (a), (b), and (c) to form the formulation.
10 . The method according to claim 9 , wherein the waterproofing polymer is a completely non-sequential reaction product.
11 . The method according to claim 9 , wherein the polyglycerol comprises at least 40% by weight, based on a total weight of the polyglycerol, of a combination of diglycerol and triglycerol.
12 . The formulation according to claim 1 further comprising an emollient.
13 . The formulation according to claim 12 wherein the waterproofing polymer is present in an amount of 60 wt % and the emollient is present in an amount of 40 wt %, each based on a total weight of the waterproofing polymer and the emollient.
14 . The formulation according to claim 13 wherein the emollient comprises caprylic-capric triglyceride.
15 . The formulation according to claim 4 wherein the (b) waterproofing polymer is present in an amount of 60 wt % and the (c) emollient is present in an amount of about 40 wt %, each based on a total weight of (b) and (c).
16 . The formulation according to claim 15 wherein the (a) sunscreen active agent is present in an amount of from 1 to 25 weight percent based on a total weight of the formulation.
17 . The formulation according to claim 4 wherein the (a) sunscreen active agent is present in an amount of from 1 to 25 weight percent based on a total weight of the formulation.
18 . The formulation according to claim 4 wherein the sunscreen active agent comprises a combination of avobenzone, homosalate, octyl salicylate, and octocrylene.
19 . The formulation according to claim 4 wherein the emollient comprises caprylic-capric triglyceride.
20 . The formulation according to claim 4 wherein the sunscreen active agent comprises a combination of avobenzone, homosalate, octyl salicylate, and octocrylene and wherein the emollient comprises caprylic-capric triglyceride.