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The Mysteries of R&D, Part I
By: Art Rich, PhD
Posted: June 22, 2010, from the July 2010 issue of GCI Magazine.
page 4 of 5
Conditioners utilize technology adopted from the textile industry. The conditioning agents work with the electrical charge on the hair, and the conditioning molecule has a “charged” end and a “lubricating” end. The charged portion attaches to the hair (which has an opposite charge) while the lubricating tail of the molecule allows one hair fiber to “slip” over the others.
Styling aids are often used to add body to the hair to hold it in position. These use film-formers to cast a film on the hair, which, upon drying, hold the hair style in place. The film-former is selected based on the required properties: firm hold, medium hold or loose hold.
Makeup. Under makeup moisturizers provide a smooth base for makeup application. These formulations are based on emulsion technology. Newer products include a sunscreen as daily, non-beach, protection from the sun. The technical challenge is that the sunscreen systems must absorb into the skin quickly, with no residual “glow” on the skin. However, the organic sunscreens are oily in nature, which will impart a glow. It is the chemist’s creativity, at this point, to find the proper blend of ingredients to provide for sun protection yet not leave a shine on the skin.
Pressed powder delivers a tint to the skin while smoothing skin appearance. These products consist of talc, colorants and a “binder.” Other materials may be present, but these are the core items. One technical challenge is to deliver the colorant in a way that it is uniform throughout the batch, without little spots of pigment agglomerate. This is achieved by making a color concentrate. Here, the dry powdered pigments are blended with a small amount of the talc. This mixture is placed in a mill where rotating metal bars break the powder blend into fine particles. This is the pigment concentrate that is then mixed with the remainder of the talc and binder. The powder is then filled into the pan, and a press is used to compress the powder. The binder’s function here is to hold the particles together in the pan.
Lipstick formulas are a blend of waxes, oils and pigments. The blend of the proper waxes and oils will dictate whether there is a stick firm enough not to melt in one’s handbag, flexible enough not to break during application, smooth enough to provide a uniform application and contain sufficient oils so as to not feel too dry on the lips. The pigments, which are supplied in powder form, must be processed to get them to a uniform and very fine state so there are no “hot spots” of color agglomerates. To achieve color uniformity the pigment powders are mixed with a small amount of the oils—often castor oil is used. This liquid blend is passed through a roller mill that reduces the size of the pigment particles in the oil. The milling continues until there are no longer any particles visible by instrumental testing. This concentrate is then blended with the rest of the oils and waxes, which have been heated until they have liquefied. The melt is mixed until uniform. It is then poured into individual molds in the lipstick shape. To accelerate the process, the molds are then placed in a cold room or cooling tunnel. When sufficiently cool and firm, they are inserted into the lipstick case.