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Do formulations requiring high salt to thicken yield poor performance?
I’ve read a lot about formulations that move the salt curve to the left (require little salt to thicken) being desirable.
But I haven’t read any clear cut info if moving the salt curve to the right yields worse results on hair or skin.
Does it? -
8 Replies
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Just make a quick search about NaCl effect or try to remember the feeling of your skin and hair after you get out from the sea and the water starts to dry.
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Sea water is about 3.5% salt. When I was on Radio Caroline at sea, after several weeks the salt started rotting my clothes and shoes to pieces.
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Considering that you rinse your hair with salt free water, I doubt there would be any measurable difference. It seems to be a myth that washing your hair with a product that contains salt is bad for hair.
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@Perry I see that you posted
Most companies will not go over 2% since NaCl can sting the eyes. Your formula will also not necessarily get thicker by adding more salt.
https://chemistscorner.com/why-does-salt-thicken-shampoos/
(In the comments replies)
Did you notice any worsened performance or sensorials with 3%+ salt ?
Thanks in advance.
As an interesting comment, this Colgate-Palmolive patent says that Ammonium surfactants need less salt to thicken, but the curve is narrower (thus easier to inadvertently get past peak viscosity) than Sodium surfactants.
https://patents.google.com/patent/EP0574086A2/en -
@Gunther - I don’t recall testing a shampoo with >3% salt so I don’t know.
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From my experience I agree with Colgate-Palmolive.
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There are wonderful surfactants that will decrease viscosity (like what you posted about glucosides).
The thing is to make the surfactant system work the way you want, viscosity can be fixed. That’s why you can usually see formulations with salt and gums.
I’d never go over 1%, now im working between 0.3-0.5%. If that’s not enough then I’ll choose another thickener.
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My usual problem is that I already have so many electrolytes that I’m on the wrong side of the salt curve.
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