Skin cream
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A skin cream is a semi-solid, spreadable preparation to be applied to the skin and consists of an aqueous ( hydrophilic ) and an oily or fatty ( lipophilic ) component, one of which is distributed in the other like an emulsion .
Physical structure
From a physical point of view, creams have a complex structure that mainly combines the structures of emulsions and gels . A distinction is made between water-washable creams (hydrophilic cream of the O / W type), in which the oily components are finely distributed in a coherent aqueous phase, and the non-washable creams (lipophilic cream of the W / O type), in which the aqueous component is dispersed in the oily phase. There are also creams that are neither clearly assigned to the O / W nor to the W / O type, but rather consist of a gel-like, coherently distributed lipophilic and hydrophilic phase (amphiphilic cream). Structures of a multiple emulsion of the W / O / W emulsion type are also discussed. Here the inner phase should again be in the form of an emulsion. Even the smallest water droplets are embedded in the inner oil phase. This type of emulsion is said to combine the advantages of W / O emulsions and O / W emulsions.
A low water content gives a cream ointment-like properties, the incorporation of larger amounts of finely ground solids leads to a pasty consistency.
Creams are to be distinguished from lotions (thick to thin emulsions, also called skin milks). Colloquially, terms such as cream, ointment, gel or lotion are sometimes used across the board.
history
Before 1911, creams and other cosmetic products contained animal fats, but these would break down and go rancid.
In 1890 Oscar Troplowitz bought the Beiersdorf company in Hamburg . In 1911 he developed the first water-in-oil emulsion for skin care with the chemist Isaac Lifschütz and the dermatologist Paul Unna . Lifschütz used wool wax alcohol ( Eucerit ) as an emulsifier. Beiersdorf named this cream Nivea (Latin nix, genitive nivis = snow).
Function and use
Lipophilic creams of the W / O type are quickly absorbed into the skin through the hydrophobic skin layers. They have a slight occlusion effect because the outer, oily phase forms a film on the skin. The release of water (evaporation) through the skin is inhibited, consequently drying out is prevented and the top layers of the skin swell up due to the water enrichment. W / O creams are preferred for the care of sebostatic ("dry") skin.
Hydrophilic creams of the O / W type cause less skin oiling and are therefore used more for the care of seborrheic ("oily") skin. In contrast to creams of the W / O type, they are not occlusive, but support the skin's ability to bind water by supplying moisture-binding substances such as glycerine , lactic acid or urea . On the other hand, an unfavorable composition via increased water evaporation (“wick effect”) can promote drying out of the skin.
In addition to the purely nourishing skin cream, which can be of the lipophilic or hydrophilic type as required, there are creams with special functions that are achieved by incorporating the appropriate substances. For example, the sun cream , in which a UV light protection is incorporated; the skin protection cream, which by adding silicone oil ( dimeticone ) protects against aggressive substances (e.g. cleaning agents, special commercial substances); or the baby cream, which has a special protective effect for the skin in the diaper area thanks to the zinc oxide content . "Anti-aging creams" contain substances that are supposed to prevent premature skin aging. Creams are used not only in the cosmetic field, but also as a basis for medicinal substances to be applied to the skin .
Starting materials in cream production
Typical components of the lipophilic phase are paraffins based on hydrocarbons (“mineral oil”) or synthetic glycerides . Vegetable fats and oils ( cocoa butter , almond oil , peanut oil, etc.) and animal waxes ( wool wax , beeswax ) are also used. Chemically modified oils ( hydrogenated castor oil , hydrogenated soybean oil ) are sometimes used because of their better shelf life and consistency. To stabilize the emulsion-like cream structure, emulsifiers are added: depending on either of the O / W type ( polysorbates , macrogol ethers, fatty alcohol sulfates, etc.) or of the W / O type (wool wax alcohols ( Eucerit ), sorbitan fatty acid esters , monoglycerides).
Creams with a high water content, especially O / W creams, are susceptible to microbial spoilage and must therefore be preserved ( sorbic acid , parabens ). Creams can also contain antioxidants ( butylhydroxytoluene , α- tocopherol ) in order to protect sensitive components from oxidation by atmospheric oxygen.
Creams can also contain humectants, consistency improvers , spreading improvers and perfumes.
The ingredients used are now indicated on the packaging of cosmetic products in accordance with an international guideline ( INCI ).
Brands
The oldest and best-known brands for skin creams in Germany are “ Nivea -Creme”, “ Penaten ” and “ Florena ”. In the course of time, entire care series developed around the main product “skin cream”.
literature
- Skin cream In: Brockhaus - the encyclopedia, digital ; Bibliographisches Institut, Mannheim 2002. ISBN 3-7653-9377-0 .
- Marianne Dolzer, Petra Doleschalek: Homemade healing ointments and tinctures . What else grandmother knew. Anaconda, Cologne 2009, ISBN 978-3-86647-318-8 .
- Sabine Ellsässer: Body care and cosmetics . A textbook for PTA training and advice in pharmacy practice. 2nd, revised and expanded edition, Springer, Berlin 2008, ISBN 978-3-540-76523-3 .
- Wilfried Umbach: Cosmetics and hygiene. 3rd edition, Wiley-VCH Verlag, Weinheim 2004, pp. 133ff, ISBN 3-527-30996-9 .
Web links
Single receipts
- ↑ C. zu Putlitz: Skin Care Products - Tradition and Trends , Praxis der Naturwissenschaften, Chemie, 6/2006, p. 2 ff.
- ↑ cf. with cosmetics - ingredients - functions. ( Memento of the original from November 23, 2010 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Industrial Association for Body Care and Detergent (PDF; 1.1 MB).
