C​ellulose HPMC in transparent paste (transparent hand soap, shower gel, shampoo)

Cellulose HPMC in transparent paste (transparent hand soap, shower gel, shampoo), low temperature opaque, how to solve it?

HPMC is used in hand sanitizers, shower gels and shampoos. Generally, it is difficult to be transparent at low temperatures. At present, there is almost no HPMC on the market that can be transparent at low temperatures in a system containing surface activity and NaCl. The main reason is that when the system has surface activity and NaCl at low temperatures (1-10 degrees), the hydrophilic properties of HPMC are challenged and will precipitate out of the system. Once the temperature returns to 15 degrees to room temperature, HPMC will slow down Slowly re-form a hydrogen bond network structure with water, dissolve again, and the system becomes transparent. It is precisely because HPMC will precipitate a small amount at low temperature that it has the performance of anti-low temperature jelly, and it is difficult to apply it in a transparent system. In addition, the different content of HPMC substitution degree groups (methoxy and hydroxypropoxy) also determines the difference in salt tolerance, low temperature precipitation, and anti-jelly performance of HPMC. For these transparent systems, such as hand sanitizers, shampoos and shower gels, you can try HEC (250HHR PC). HEC does not have the characteristic of low-temperature precipitation. It is just that in the initial stage of selection, it needs to be tested and tested with HEC. In the process, you can immediately observe whether the two are compounded or not. When the surface active system and HEC are compounded at room temperature, they will not precipitate at low temperature and can ensure low temperature transparency. Most of the traditional anionic surfactants and HEC have relatively good compounding performance, while the compounding of amphoteric and non-ionic surfactants with HEC will be challenging, and there is a limit to the dosage.