We are formulating with HEC as a thickener in the formula, and the pH is between 6-7. The initial viscosity was well above 4000 cps, but after 30 and 60 days in the chamber (40C), the viscosity dropped significantly, however the entire shampoo is still clear without any phase separation.
I am wondering if anyone has similar experience with viscosity change of HEC thickened shampoo or other cellulose thickened systems?
Much appreciated!
General formula:
Surfactant blend (40% active) 16%
HEC (Tylose 100000) 1%
Cationic conditioner 0.5%
PE82 1%
Sodium Benzoate 0.5%
Citric acid q.s. to pH 6-7
Humectant ~1%
Water q.s
Comments
Thank you for your response!
Yes I did disperse HEC in cold water then activate it with alkali ingredients, and the viscosity was achieved to 4000 cps after batching, which is desirable for our product (the surfactant blend does not thicken much). However when it sits in chamber it's slowly losing its viscosity, therefore I am wondering if some sort of hydrolysis would happen at pH 6-7.
PE82 is 80% phenoxyethanol and 20% ethylhexylglycerin.
Thank you Matt! We do have some amino acid derivatives for claim purposes. This is very interesting and I'll need to keep that in mind when I formulate.
At first I noticed I wasn’t letting it hydrate long enough. Then I thought I did (was heating it up to 75C and a couple drops of 10% NaOH, stir for 10min), and in a few occasions adding an amphoteric surfactant would kill the viscosity.
But then... I’ve read HEC is used to thicken acidic toilet bowl cleaner.