16 HYGIENE


biocidal effect. Many distillers in the United States and Great Britain now have benefited from the supplementary production of hydroalcoholic sanitisers with a pronounced fuselol scent. So, let us take a closer look at what other


improvements can be made without sacrificing the biocidal effect of alcohol- based disinfectants. Recently, Lubrizol Advanced Materials increased the supply of original Carbopol polymers in response to the growing demand for thickening agents used in a number of hand sanitising gels and cleansers. Gelled systems with the 60– 90% ethanol/isopropanol concentration can be prepared to add Carbopol polymers.14 Carbopol 980, Carbopol Ultrez 10 (both of Carbomer-type), and Carbopol Ultrez 21 (Acrylates/C10-30 Alkyl Acrylate Crosspolymer) in the dosage of 0.2-0.8% are suggested for preparing clear viscous gels with 60% alcohol or more. Choosing the correct neutralising agent is a critical point in formulating a hydroalcoholic gel with Carbopol polymers. Bases, such as NaOH or NH4OH generally used to neutralise Carbopol polymers in aqueous systems, do not work as neutralising agents in hydroalcoholic sanitisers. Organic neutralising bases, as shown in Table 1, are the better choice for thickening clear gels with a high alcohol content. Slightly crosslinked carbomers, as dry


pre-neutralised solids or polymer latexes, are in the portfolio of some other suppliers, e.g.: OptaSense G41 of Croda, Flogel FG of SNF, and Synthalen CH of 3V Sigma. Other chemically related alcohol- compatible thickeners are: Rheocare TTA – Acrylates Copolymer of BASF; Structure 2020 – Acrylates Crosspolymer-6 of Nouryon; Jeethix T – Sodium Acrylate/Sodium Acryloyldimethyl Taurate Copolymer of Jeen; UltraThix 20 – Acrylates/C10-30 Alkyl Acrylate Crosspolymer of Ashland; Aristoflex Velvet – Polyacrylate Crosspolymer-11 and Aristoflex AVC – Ammonium Acryloyldimethyltaurate/VP Copolymer, both of Clariant. Lucas Meyer recommends Lecigel (Sodium Acrylates Copolymer and Lecithin), a versatile ingredient, which offers thickening at a high level of ethanol (up to 70%) along with silky skin touch, anti- drying, and anti-irritating properties. Two mild prototype formulations of


hydroalcoholic hand sanitisers with Carbopol Ultrez 10 and Aristoflex Velvet as thickeners are shown in Table 2 and Table 3, respectively. Both sanitiser compositions reveal skin care additives alternative to glycerin. In Lubrizol’s formula, multi- functional and mild ingredient Glucam E-20 Humectant is used for delivering a light, satin-like emollient feel and skin moisturising. It is 100% ethoxylated methyl glucose ether with low irritation potential


PERSONAL CARE EUROPE


Table 4: On the Go Hand Sanitizer Phase Ingredients


A Deionized Water Glycerin


Crodarom Nordic Cotton (Water (and) Glycerin (and) Eriophorum Spissum Flower/stem Extract)


Fruitliquid Cloudberry (Glycerin (and) Water (and) Rubus Chamaemorus Fruit Extract)


Glycerox 767 (Peg-6 Caprylic/Capric Glycerides) Propylene Glycol


Arlasilk PTM (Myristamidopropyl PG-Dimonium Chloride Phosphate Benzalkonium Chloride 1% FD&C Green #5 1% FD&C Yellow #5 10% NaOH Solution


%


90.89 2.00


2.00


2.00 1.00


1.00 1.00 0.10 q.s. q.s.


0.01


Procedure: Premix the Glycerox 767 and propylene glycol. Combine the remaining ingredients and stir until completely homogenous. Add the premix while stirring. Add the colourants and adjust the pH to 6-6.5 with sodium hydroxide.


Properties: pH: 6.07 Viscosity: -water thin, 10cPs (Brookfield RV#2 @ 10rpm, at Room Temperature)


Suppliers: 1 Croda/Crodarom


that makes it ideal for sensitive skin formulations. Additives of PEG-12 Dimethicone and aloe vera juice offer non- sticky feeling, emolliency, skin hydration, and soothing in the sanitiser composition of Clariant. If a manufacturer of a hydroalcoholic


sanitiser is looking for a more natural rheological additive, then nonionic hydroxyethyl cellulose, hydroxypropyl methylcellulose, or similar starch derivatives may be a good choice. They offer better skin hydration but may require a higher dosage to achieve the desired viscosity. As revealed by Solvay Novecare, Jaguar HP- 120 (INCI: Hydroxypropyl Guar) is compatible with high levels of ethanol and act as a humectant/emollient. Comparing with the widely marketed hand sanitisers thickened with Carbomer polymer, the alcoholic formula of sanitiser with Jaguar HP-120 gives no residual sticky after-feel. Ethanol, isopropanol, and the like small


molecules are known permission enhancers to the human skin. This is an unwanted effect on the skin if your formulation contains a cleansing surfactant or a cationic biocide, such as benzalkonium chloride. Therefore, alcohols and surfactants are rarely combined in leave-on sanitisers to avoiding skin coarsening and irritation. However, silicone surfactants like dimethicone copolyol do not usually produce irritation or toxicity when applied to the skin, as was shown in the patent application of DEB, subsidiary of SC Johnson.15


Alcohol-based foamable hand


sanitizing compositions described therein can be exemplified as a useful option. The


proposed leave-on disinfecting compositions contain up to 80% of ethanol, (iso)propanol or a mixture thereof, and additionally, the bifunctional silicone surfactant bis-PEG/PPG-X dimethicone, where X is from 10 to 20 repeating EO or the EO/PO groups. Benefits of the silicone surfactant in the sanitising composition consist of foaming, emolliency, and good after-feel on skin. Using other surfactants, such as PEG-7 Glyceryl Cocoate, is beneficial in these formulas. In spite of the high content of foam-breaking alcohol, hand sanitiser comprising dimethicone copolyol gives stable foam so it can be delivered with a self-foaming dispenser. The use of polyethylene glycol (PEG)


was proposed as an economical humectant- type emollient. Sanitising hand lotion described in the invention16


can be


exemplified by the following composition: isopropanol – 70% v/v, chlorhexidine gluconate – 5 g/L, PEG – 1.5%, and water to balance. Other ethylene oxide derivatives and diols, such as Glycereth-7, Glycereth-26, Sorbeth-30, Hydroxyethyl Urea, Dipropylene Glycol, Methylpropanediol, Hexylene Glycol, and Caprylyl Glycol, are proved to support skin moisturising and integrity. The sanitiser compositions comprising


aloe vera gel as a moisturising and anti- inflammatory additive and cellulose or guar derivative or xanthan gum as a gelling agent may be a good choice for a consumer committed to an organic or vegan lifestyle. It is worth saying that mentioned polysaccharide thickeners cannot be used in products marketed as


November 2020


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