Chemical Engineering Department, Manhattan College, 4513 Manhattan College Pkwy, Bronx, NY, 10471, USA.
Int J Cosmet Sci. 2020 Jun;42(3):259-269. doi: 10.1111/ics.12609. Epub 2020 Apr 24.
The main objective of this paper was to optimize hair conditioner performance through variation of composition utilizing automated cosmetic formulation platform and advanced characterization techniques as well as develop understanding of how performance (wet combing and wet lubrication) of hair conditioner is affected by its rheology (i.e. yield stress) and controlled breakdown of the formulations (dilution). The experimental results show that yield stress greatly impacts rheology, stability and performance of the lamellar gels for hair conditioning.
All samples were prepared on the Chemspeed Flex Formax. A mechanical rheometer was used to measure bulk viscosity and yield stress in each sample. Dia-stron tensile tester was used to measure the lamellar gels ability to reduce combing force. Potential stronger lamellar gel network formation in the formed lamellar gels potentially leads to higher yield stress exhibited. Viscosity values were also measured after a controlled breakdown (i.e. dilution) of each sample. This was also carried out using a mechanical rheometer.
Yield stress of the formulations was engineered through composition variation and was recorded in each system. The highest yield stress value is 251.179 Pa at a BTAC/CA ratio of 6:10, and the lowest yield stress is 50.14 Pa at a BTAC/CA ratio of 6:5. The highest yield stress value is 50.14 Pa at a CTAC/CA ratio of 6:10, and the lowest yield stress is 19.98 Pa at a CTAC/CA ratio of 2:10. The highest overall yield stress values can also be observed in the BTAC/CA system, whereas the CTAC/CA system has relatively lower yield stress values. Dilution of each formulation caused a breakdown in viscosity of each formulation with the formulations with highest yield stress maintaining higher viscosity than the other formulations. The formulations with highest yield stress in each system which also maintains the highest dilution viscosity (6% BTAC/10% CA and 6% CTAC/10% CA) have the best effect on reducing overall combing force, that is from dry hair tress to wet hair tress and after product is rinsed off. At a BTAC/CA system of ratio 6:5, there is an 89% reduction in combing force and a 95% reduction in combing force in the BTAC/CA system of ratio 6:10. At a CTAC/CA system of ratio 2:10, there is a 65% reduction in combing force and a 88% reduction in combing force in the CTAC/CA system of ratio 6:10. A 'conditioned' soft feel was observed on each hair tress as the sample was applied and after it was rinsed off.
The overall performance of the lamellar gels for hair conditioning can be engineered through optimization of the formulation microstructure and formulation microstructure breakdown on dilution.
本文的主要目的是通过利用自动化化妆品配方平台和先进的特性分析技术来改变组成，从而优化护发素的性能，以及研究其流变性能（即屈服应力）和配方的可控降解（稀释）如何影响护发素的性能（即湿梳理和湿润滑）。实验结果表明，屈服应力对层状凝胶的流变性能、稳定性和调理性能有很大的影响。
所有样品均在 Chemspeed Flex Formax 上制备。使用机械流变仪测量每个样品的体粘度和屈服应力。Dia-stron 拉伸试验机用于测量层状凝胶减少梳理力的能力。在形成的层状凝胶中可能形成更强的层状凝胶网络，从而导致表现出更高的屈服应力。还使用机械流变仪测量了每个样品的受控降解（即稀释）后的粘度值。
通过组成变化来设计配方的屈服应力，并在每个系统中记录。BTAC/CA 比为 6:10 时，最高屈服应力值为 251.179 Pa，BTAC/CA 比为 6:5 时，最低屈服应力值为 50.14 Pa。CTAC/CA 比为 6:10 时，最高屈服应力值为 50.14 Pa，CTAC/CA 比为 2:10 时，最低屈服应力值为 19.98 Pa。BTAC/CA 系统中可以观察到最高的整体屈服应力值，而 CTAC/CA 系统中的屈服应力值相对较低。每种配方的稀释都会导致每种配方的粘度下降，而具有最高屈服应力的配方保持的粘度高于其他配方。每个系统中具有最高屈服应力的配方，并且保持最高稀释粘度（6% BTAC/10% CA 和 6% CTAC/10% CA），对降低梳理力有最好的效果，即从干发绺到湿发绺，然后冲洗掉产品。在 BTAC/CA 比为 6:5 的系统中，梳理力降低了 89%，BTAC/CA 比为 6:10 的系统中梳理力降低了 95%。在 CTAC/CA 比为 2:10 的系统中，梳理力降低了 65%，CTAC/CA 比为 6:10 的系统中梳理力降低了 88%。在应用和冲洗后，观察到每个发绺都具有“调理”后的柔软触感。
通过优化配方的微观结构和配方在稀释时的微观结构降解，可以对头发调理用层状凝胶的整体性能进行工程设计。
