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UV boosting of Stearalkonium Hectorite

IP.com Disclosure Number: IPCOM000245474D
Publication Date: 2016-Mar-11
Document File: 6 page(s) / 82K

Publishing Venue

The IP.com Prior Art Database

Abstract

Described is the the use of Cosmedia gel CC (INCI: Dicaprylyl Carbonate (and) Stearalkonium Hectorite (and) Propylene Carbonate) to boost UV protection after water contact.

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Background

The present disclosure relates to the use of Cosmedia gel CC (INCI: Dicaprylyl Carbonate (and) Stearalkonium Hectorite (and) Propylene Carbonate) to boost UV protection after water contact.

Today sunscreens often claim to be water resistant, meaning they provide still 50% of the initial protection after water contact (1). However, they are not able to maintain their entire UV protection and a part of the initial UV protection is removed after water contact such as with swimming, or with perspiration as during sport activities. Therefore, an effective sunscreen formulation should maintain its efficacy even after contact with water or with perspiration.

We found that Cosmedia Gel CC (INCI: Dicaprylyl Carbonate (and) Stearalkonium Hectorite (and) Propylene Carbonate) is able to increase the UV protection after water contact; the interaction of the formulation containing Cosmedia gel CC with the water resulting in the achievement of a more uniform film on the substrate. This phenomenon was described previously by Shiseido with the wet force technology (2). The concentration of hydrophobically modified Hectorite (eg. Disteardimonium Hectorite, Stearalkonium Hectorite) ranged between 0.1 to 1%.

Method used for performance testing of sunscreens before and after water contact

An amount of 1.2mg/cm² of sunscreen was applied on PMMA plate substrate. The used PMMA plates are molded followed by a sand blasting step; they show a roughness Ra of around 6µm. Three plates were used per tested sunscreen formulation. SPF in vitro is deduced from spectral UV transmittance measurements recorded from 290 to 400 nm through the sunscreen-covered PMMA plates using the Labsphere UV-2000S before and after water contact.

After sunscreen application, the UV transmittance was measured to calculate the SPF in vitro before water contact and then the sunscreen-covered plates were immersed for 15min in a recipient containing tap water. The temperature of the water bath was maintained at a value between 23 and 25°C. After removal of the sunscreen-covered PMMA plates from the water bath, the UV transmittance was measured again, the SPF in vitro after water contact calculated and compared to the SPF in vitro before water contact.

Results

Table 1 gives the SPF in vitro before and after water contact for different W/O (Water-in-Oil) and W/SI (water-in-Silicone) sunscreens, with and without Cosmedia gel CC

Sunscreen

W/O Nr1 With 5% Cosmedia Gel CC 68

Without Cosmedia Gel CC 46

W/O Nr2 With 2% Cosmedia Gel CC 82

Without Cosmedia Gel CC 60

W/Si With 4% Cosmedia Gel CC 37

Without Cosmedia Gel CC 39

UV boosting of Stearalkonium Hectorite

UV boosting of Stearalkonium Hectorite

SPF in vitro

before water

contact

SPF in vitro

after water

contact

after water

contact (%)

Increase of SPF

288 323%

61 32%

109 33%

71 18%

56 201

79 153


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UV boosting of Stearalkonium Hectorite

• W/O Nr1 was based on the emulsifier mixture Dehymuls PGPH (INCI, Polyglycer...