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Sulphate free thickening
Having run a 5 Kg batch today (scaling up from the 1 Kilo test batches) I was able to confirm my tests, although the batch came out a little too thick and had to be diluted slightly.
The original formula in terms of its surfactants is a combination of carboxylic acid, betaine, and cocoamphoacetate. It has pH=5.5, so many thickeners won’t work with it, and since this is for humans I want the pH as it is and not at 6.5 or above.Gums and so on (e.g. Xanthan) aren’t easily come by in my city, so I use Glucamate VLT which not only thickens but has great hand-feel unlike say, a carbomer or PEG-150 (I found this latter had a ‘breaking’ type hand-feel). I wasn’t happy with the hand-feel produced by the PEG-150.The downside with VLT is that it’s pretty expensive stuff and our costs were going too high because I was having to use almost 4%Adding 2% MEA and changing to a semi-hot process has reduced the VLT% to 2% in the latest trial, and slightly too thick, so I will begin shaving 0.1% at a time until I have it dead on. (It’s not a linear thickening curve).At the same time, foaming has definitely improved. It’s always tough to get a good foam profile with sulphate free unless you use tons of surfactant which makes it uneconomic. Now though, I have foam that’s getting on for as good as anionic shampoos.With hindsight, I should have tried this before. I checked the sulphate-free shampoos on offer from about 5 different mfrs and they all had MEA. -
4 Replies
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Innospec offers some great sulfate free blends that are readily thickened with salt.
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@belassi you are writing story?
its such a long text that reading and understanding is difficult
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@belassi I really enjoy reading about your experiences in the lab
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Thanks Sarah. I do enjoy product design. Sometimes I think, “so many ingredients, so little time!”
@chemist1: I checked with UL Prospector and it appears that Innospec don’t make their surfactants available in Mexico, unfortunately.
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