Leverkusen, Germany -- It's not a traditional use for polyurethane, but cosmetic materials are exploiting some novel properties of the material that give distinct advantages -- specifically in meeting environmental demands and in making waterproof sunscreen formulations which retain a pleasant, 'silky' feel, according to developer Bayer MaterialScience.
Bayer's Baycusan C cosmetics products meet key requirements for "green" raw materials, being water-based with no preservatives or co-solvents. And sister material Baycusan C 1000 can raise the sun protection factor (SPF) of sunscreen cosmetics without use of UV absorbers. It also makes formulations waterproof -- but also offers smoothness without stickiness, BMS said.
"We are able to offer Baycusan C products without preservatives, because they are manufactured and filled at our plant in Chempark Dormagen using a germ-free, ultraclean and high-quality process developed in-house," said Dr Steffen Hofacker, head of cosmetics at BMS, in an 11 March company statement.
Cosmetic companies gain freedom in product design and preservation, Hoffacker continued, adding that the Baycusan C range includes a polyurea powder as a sensory additive and four solvent-free polyurethane dispersions with film-forming and conditioning properties. These raw materials can be used to good effect in skin-care products, decorative cosmetics, sunscreen and hair styling products, according to BMS.
In Baycusan C manufacture, process by-products such as waste are minimised, and chemical reactions use energy-saving and efficient procedures under mild conditions, Bayer said.
BMS will spotlight these 'green' credentials at Stand G 70 in Hall 7.3 at In-Cosmetics, the world's leading trade fair for cosmetic raw materials, in Paris 13-15 April this year.
Another BMS focus at the show will be on test results validating the benefits of the PU material Baycusan C 1000 for sunscreen formulations. This film-forming polymer raises the SPF of sample formulations, without UV-absorbers, the company explains.
The SPF booster has the added benefit of making sunscreen products extremely waterproof.
"We developed and tested a whole series of possible formulations, varying the UV-A and UV-B filters, both inorganic and organic, while doing so. In our suggested formulations, we also took into account the fact that people in various countries around the world have very different ideas about the ideal skin feeling," said Dr Sophie Viala, head of cosmetics application engineering at BMS.
"Baycusan C 1000 offers the perfect solution to a well-known dilemma: how to respond to the trend towards ever-higher protection factors without compromising on the pleasant skin feeling provided by products with lower SPF values," Viala claimed.
Without boosters, SPF can only be increased by using higher concentrations of UV filters, and usually makes sunscreens feel wax-like, greasy or sticky on the skin, according to BMS. In contrast, Baycusan C 1000 forms elastic films that feel "very pleasant on the skin," the company said. Tests also confirm that they support a high level of water-vapour transmission and allow the skin to breathe, the company said.