Personal Care

Material selection for personal care

Personal care products such as creams, lotions, shampoos, conditioners, cleansing bars, deodorant sticks and colour cosmetics use oleochemicals as emollients, thickeners, emulsifiers, humectants and surfactants. Most of these materials are derived from palm, palm kernel or coconut oil, and the same molecule may be offered in technical, cosmetic or pharmacopoeial grades. Choosing the right grade matters as much as choosing the right chemistry.

What the formulation needs. Emulsions need a consistent thickening and stabilising system, and fatty alcohols and stearic acid do much of that work. Cetyl (C16), stearyl (C18) and cetostearyl (C16–C18) alcohols build viscosity and body in creams and conditioners and act as co-emulsifiers. Stearic acid, partly neutralised in the formulation, forms the classic vanishing-cream base and gives a pearlescent finish. Esters such as isopropyl myristate, isopropyl palmitate and cetyl palmitate adjust spreadability, skin feel and structure. Glycerine is the standard humectant. Surfactants provide cleansing and foam, from sodium laureth sulphate and cocamidopropyl betaine in shampoos to sodium cocoyl isethionate in syndet bars and alkyl polyglucoside in mild cleansers.

Key specification parameters. For fatty alcohols, check the chain distribution (for example the C16:C18 ratio of cetostearyl alcohol), hydroxyl value, acid and saponification values, which reveal residual acids and esters, and iodine value, melting range and colour. For stearic acid, the C16/C18 ratio, iodine value, colour and titre govern texture and colour stability. Esters are specified by purity or ester content, acid value, saponification value and odour. For glycerine, assay, colour, water and the pharmacopoeial tests for diethylene glycol and ethylene glycol are central. Surfactants are specified by active matter, pH and colour and, for ethoxylated grades, by residual 1,4-dioxane.

Recommended product types. Cetyl, stearyl, cetostearyl and myristyl alcohols. Triple-pressed stearic acid and glycerol monostearate. Isopropyl myristate, isopropyl palmitate and cetyl palmitate. Refined glycerine. Sodium laureth sulphate, cocamidopropyl betaine, sodium cocoyl isethionate and alkyl polyglucoside. Caprylic, capric and lauric acids as ester and surfactant intermediates.

Documentation. Cosmetic formulators typically ask for a specification, certificate of analysis, safety data sheet, allergen and CMR statements, and origin information such as a vegetable-origin declaration. Pharmacopoeial (USP or Ph. Eur.), halal, kosher or sustainable palm claims need certificates that cover the specific grade and site, so ask for the certificate scope with your quotation rather than assuming it from the product name.

Handling and shipping. Fatty alcohols and stearic acid are supplied as flakes or pastilles, usually in 25 kg bags. Store them cool and dry, because they cake under heat and pressure. Esters and surfactant solutions are shipped in drums, IBCs or tank containers. Some surfactant concentrates form thick gels when diluted to intermediate concentrations or are sensitive to temperature, so follow the storage and dilution guidance for the specific grade.