Shampoo and Conditioner Science 110 Silicone Conditioners Silicone quaternaries have long been known as hair conditioning compounds. A recent patent application from Evonik Goldschmidt is directed to silicone quats that confer conditioning with longer lasting conditioning through several shampoo cycles. The premise is that long-term substantivity to hair requires the conditioning agent to contain a string of cationic charges. This was achieved by Goldschmidt by polymerizing cationic monomers and grafting them to silicone backbones. In general, water-soluble monomers polymerized in the presence of silicones yield a mixture of water-soluble polymers and unsubstituted silicones because the two ingredients are incompatible and attachment of the polymer chain to the silicone would require appropriate “coupling groups.” The Evonik researchers rose to the challenge by polymerizing the cationic monomers in the presence of silicone polyethers. The ether groups are compatible with the quat monomers, and they readily chain transfer to give graft copolymers. Once grafted, the copolymers are quaternized to confer permanent positive charges with enhanced substantivity to hair. The grafts are obtained by polymerizing the readily available monomers, dimethylaminoethylmethacrylate or 3-trimethylammoniopropyl-methacrylamide. Leave-on silicone conditioners specifically targeted to non- shampoo applications confer enhanced and relatively durable conditioning. These contain emulsified vinyl-terminated silicones applied in combination with a conventional cationic conditioner. A preferred product type is a mousse. These silicone block copolymers can achieve excellent conditioning at relatively high viscosities (100 KPa/s-1). Improved conditioning that confers surprisingly reduced friction on hair can be achieved by including an aminosilicone in which the aminosilicone has a fairly large range of average particle sizes from about 5–50 microns.97
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