Beiersdorf AG, Research & Development, Unnastraße 48, 20245, Hamburg, Germany.
Int J Cosmet Sci. 2012 Oct;34(5):458-65. doi: 10.1111/j.1468-2494.2012.00734.x. Epub 2012 Jul 24.
The perceived skin feel during and after application of skin care products is highly important to the consumer and therefore to cosmetic formulators. Powder particles are commonly incorporated in cosmetic formulations to improve their sensory properties. Although a large variety of cosmetic powders is available, it is presently uncertain how the particles' properties affect the perceived skin feel. Well-trained panellists usually assess the perceived skin feel; however, these tests are time-consuming and by nature subjective. To address this complexity, the authors have systematically investigated various suspensions of cosmetic powders with regard to the perceived skin feel after application. Furthermore, an in vitro friction measurement set-up was developed which features a tribological contact similar to the mechanical properties and the topography of the contact between finger tip and human skin. A correlation was found between the friction coefficients determined in vitro and the perceived skin feel after sample application (as assessed by a descriptive panel). The results indicate that cosmetic powder particles should be small with a rather irregular shape to better lubricate the tribological contact between finger tip and skin surface, which leads to a more 'powdery' skin feel. It is suggested to carry out further tests with different powder particles or other skin care formulations to fully understand the underlying mechanisms of skin feel improvement and to validate or even partly replace the results of panel testing.
消费者非常关注护肤品在使用过程中和使用后的肤感，因此这对化妆品配方师来说非常重要。粉末颗粒通常被加入化妆品配方中以改善其感官性能。虽然有各种各样的化妆品粉末，但目前尚不清楚颗粒的特性如何影响感知的肤感。经过良好培训的品评员通常会评估感知的肤感；然而，这些测试既耗时又具有主观性。为了解决这一复杂性，作者系统地研究了各种化妆品粉末悬浮液在涂抹后的肤感。此外，还开发了一种体外摩擦测量装置，该装置具有类似于指尖和人体皮肤之间的机械性能和接触形貌的摩擦接触。在体外确定的摩擦系数与样品涂抹后的感知肤感（由描述性小组评估）之间存在相关性。结果表明，美容粉颗粒应具有较小的尺寸和较不规则的形状，以更好地润滑指尖和皮肤表面之间的摩擦接触，从而产生更“粉状”的肤感。建议进行更多具有不同粉末颗粒或其他护肤品配方的测试，以充分了解改善肤感的潜在机制，并验证甚至部分替代小组测试的结果。
