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Why the viscosity of sulfate-free shampoo dropped after adding the menthol crystal?
Hi everyone.
My sulfate-free shampoo’s viscosity dropped after adding the mixture of menthol and fragrance.
Below is my ingredients.Cocamidopropyl betaine
Disodium Cocoyl Glutamate
Decyl Glucoside
Glucamate VLT
PEG-7 Glyceryl Cocoate
PQ-7
Cocamide MEA
Euxyl PE 9010
Fragrance
Menthol - 0.5%
PQ-10
Disodium EDTAPls help me to increase the viscosity to 5000cps. Thanks.
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3 Replies
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Experimentation is one of the keys to success in cosmetic chemistry. I’ll give more details on
that below.One of the others is knowing your raw materials. At a bare minimum, you should have a
Technical Data Sheet (TDS), a Specification Sheet and/or a Certificate of
Analysis, and a Safety Data Sheet (formerly a MSDS) for each and every one of
your ingredients. Ideally, you would have read and kept a copy of all of the
supplier literature available for every chemical (and not just the literature
from your supplier) that you are using.After you have (at least) read all of the technical data sheets, it should be a little easier to
fix your formula, For example, in your formula, one of the ingredients that
provides thickening is Glucamate VLT. Here’s the experimentation part - you
need to make a series of batches that use increasing amounts of Glucamate VLT
until you have reached a viscosity you are comfortable with. Then you need to
duplicate this experiment with any other thickeners you’re using. Then, you
need to see if any of the thickeners are synergistic with each other. By this
point, you should be fairly comfortable with using the chemicals that thicken
your batch, and you will be able to answer your own question. -
Experimenting is the key. You could try using more surfactant, less menthol, less fragrance. Add a thickener. Lots you can do but you have to experiment.
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I’m very familiar with the Glucamate VLT. First, the PEG-7 Glyceryl Cocoate will negatively impact viscosity, I would replace it with glycerin.
The menthol and fragrance always will reduce viscosity, you’ll have to increase the VLT to compensate. VLT does not have a linear thickening profile. As you approach the necessary amount, small additions cause large viscosity increases.I found that using 1% of cocamide MEA allowed 2.75% VLT. More MEA than 1% precipitated after several days.
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