SUN CARE 55
Table 1: Formulation Material
Water Carbomer
Disodium EDTA Triethanolamine Octocrylene Octisalate
Oxybenzone Avobenzone Stearic Acid
Sorbitan isostearate
Polyglyceryl-3 Distearate Dimethylpolysiloxane VP/Eicosene Copolymer Methylparaben
Stearyl/Octyldodecyl Citrate Crosspolymer
Acrylates / Octylacrylamidecopolymer. A
83.10 0.25 0.05 1.00 3.00 3.00 2.00 1.00 1.00 1.00 1.00 0.50 2.00 0.10
0.00 B
83.10 0.25 0.05 1.00 3.00 3.00 2.00 1.00 1.00 1.00 1.00 0.50 0.00 0.10
2.00
environmentally responsible; it is increasingly requested by the public and required by governments worldwide.6 In this exercise, the film-former was found
to be lacking in biodegradation properties and in aesthetics (waxy feel). The first approach was to substitute a polyester film-former (same function in formulation) into a current formulation to study effectiveness of the formulation and changes to biodegradation and aesthetics. The same concentration was used that is the film-former was a part for part drop into the existing formulation. Traditionally, high molecular weight, free
radically based, polymers have been employed to impart water-resistance in sun care products:
“Traditional film forming polymer is a hydrophobic, high molecular weight, carboxylatedacrylic copolymer.” VA / Butyl Maleate/IsobrnylAcrylate
Copolymer “...polymer is positioned for hair spray applications where it delivers stiff, hard-holding performance.” Journal of Cosmetic Science: There is an
article entitled “Investigating Film Properties of Polymers Used in Anhydrous Sunscreen Formulations Using Scanning Electron Microscopy (SEM)
.1.Thompson, W.; Kennedy, D.; Gillence, T.; McMullen, R.L.; Senak, L J. Cosmet. Sci., 69, 2018, 203.
Plastic free film-formers The formulation evaluated is shown in Table 1. SPF and Water Resistance results for the two formulations are shown in Table 2.
Biodegradation It has been shown that stearyl/octyldodecyl citrate copolymer degrades by 40% in 28 days, while the backbone of poly (acrylate) degrades 0.12 – 0.24% in six months.7 Material must be run without additional solvent and using approved methods.
Conclusions There are many times when a formulator wishes to alter the performance of a personal care formulation by addition of a small concentration of a particular new surface active polymer. This approach referred to as ‘minimally disruptive Formulation’ (MDF) is often the most efficient approach.
Table 2: SPF and Water Resistance in vivo SPF
A B
Water Resistance
28.85 83.10
5 subject 80 mins water immersion
There are other times in which
replacement of a raw material is the preferred approach. In this instance the raw material being replaced should be replaced with a new raw material which has a functional similar property, rather than just share a chemical type. In the example cited in this work, an
acrylate-based film-former is replaced with a polyester polymer. The function is the formula is the same (film-former) but the chemistry is very different. The film functionality was maintained as
was the SPF, but the aesthetics and biodegradability were improved. In addition, the new film-former is not a plastic.
References 1
https://tinyurl.com/yyqhern4 2
https://tinyurl.com/y2p6tcjj 3
https://tinyurl.com/y6nxpkpd 4
https://tinyurl.com/y4cbm9g6 5
https://www.scconline.org/scc-webinars- innovating-with-minimally-disruptive- formulations-mdf/
6
www.productstewardship.us/default.aspx 7 Mellou F, Varvaresouand A, Papageorgiou S. Renewable sources: applications in personal care formulations, Inter J Cos. Sci. 2019,
https://doi.org/10.1111/ics.12564
PC
October 2020
PERSONAL CARE NORTH AMERICA
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