Thickeners for Liquid Soap - Chemists Corner

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Formulating

Thickeners for Liquid Soap

Posted by Cosmetic_Chemist on February 14, 2022 at 9:33 pm

Hello everyone,

I am trying to achieve a liquid soap concentrate such that 10% of the concentrate and 90% water result in a nice thick liquid soap.

I have tried a couple different surfactant blends paired with Cocamidopropyl betaine however I am not able to obtain the desired consistency at the end.

What thickeners would you recommend?
I tried hydroxyethylcelluse at 2% but it was not compatible with cocamidopropyl betaine. The solution just broke upon mixing.

If i were to use iselux mild surfactant blend, what thickeners do you think would work best?

would Xanthan gum work?

Rockstargirl replied 2 years, 9 months ago 10 Members · 16 Replies
16 Replies

Paprik

Member
February 14, 2022 at 10:54 pm

Why do you think HEC is not compatible with cocamidopropyl betaine?
I checked some example formulations from suppliers and they are using it along with HEC.
(However I do have some issues with HEC now too. I actually made a post not long ago. Waiting for some help).

For surfactant systems it is recommended to use hydroxypropyl methylcellulose aka Methocel.

You could use Xanthan Gum, but I would rather choose higher grade, otherwise you’ll end up with snotty stringy looking product.

If you could also share your formula, we would be able to take a look and give you some tips.
Rockstargirl

Member
February 14, 2022 at 11:51 pm

Agree to share formula, if you’re adding scent…that can break it as well.
MarkBroussard

Member
February 15, 2022 at 12:02 am

@Cosmetic_Chemist

If you are using Iselux Mild, I would recommend using Hydroxypropyl Starch Phosphate as a thickener. It will also improve the density of your foam. Much easier to work with than the cellulosic thickeners.
Cosmetic_Chemist

Member
February 15, 2022 at 2:19 pm

Paprik said:

Why do you think HEC is not compatible with cocamidopropyl betaine?
I checked some example formulations from suppliers and they are using it along with HEC.
(However I do have some issues with HEC now too. I actually made a post not long ago. Waiting for some help).

For surfactant systems it is recommended to use hydroxypropyl methylcellulose aka Methocel.

You could use Xanthan Gum, but I would rather choose higher grade, otherwise you’ll end up with snotty stringy looking product.

If you could also share your formula, we would be able to take a look and give you some tips.

Currently its just a base formula:

Iselux Mild
Cocamidopropyl Betaine
Glycerin
Citric Acid
Phenoxyethanol
Aloe Vera Gel
Tocopherol Acetate
Essential Oil - 0.2% for fragrance

I might add some conditioning agents later on once I have a better idea about the base.

I will try methocel and hydroxypropyl starch phosphate. Thank you so much!
Let me know if the formula calls for another one.
Paprik

Member
February 15, 2022 at 6:22 pm

Just a couple of thing to your formula.

Iselux Mild -
Aqua (and) Sodium Lauroyl Methyl Isethionate (and) Cocamidopropyl Betaine (and) Sodium Methyl Oleoyl Taurate (and) Lauryl Glucoside (and) Coco-Glucoside

It has all surfactants. Not sure why adding more Cocamidopropyl Betaine?
Also, Isethionates and Taurates should thicken with salt present. Have you tried adding NaCl in 0.3 - 0.5% increments? Add after you adjust your pH to > 6. This may also help.

Not sure how much of the ingredients are you using. Percentages are really useful for us.

Totopherol acetate is pointless. It is not antioxidant for the essential oil, only for skin. However, in wash off products? No point. Change it for “normal” Tocopherol.
GeorgeBenson

Member
February 15, 2022 at 6:51 pm

I have used Iselux Ultra Mild and did not find salt to work very well to thicken it. Iselux SFS on the other hand is very easily thickened with salt.

I have had success using HPMC, Polyquaternium-10, and Sorbithix to thicken. There are many PEG-type thickeners too such as crothix but I haven’t used those.

Xanthan will thicken but I find even the soft grade does give it an undesirable (to some) texture as well as making it harder to rinse off.

Also, just using a higher percentage of ultra mild will make for a much thicker soap.
Cosmetic_Chemist

Member
February 15, 2022 at 8:36 pm

Paprik said:

Just a couple of thing to your formula.

Iselux Mild -
Aqua (and) Sodium Lauroyl Methyl Isethionate (and) Cocamidopropyl Betaine (and) Sodium Methyl Oleoyl Taurate (and) Lauryl Glucoside (and) Coco-Glucoside

It has all surfactants. Not sure why adding more Cocamidopropyl Betaine?
Also, Isethionates and Taurates should thicken with salt present. Have you tried adding NaCl in 0.3 - 0.5% increments? Add after you adjust your pH to > 6. This may also help.

Not sure how much of the ingredients are you using. Percentages are really useful for us.

Totopherol acetate is pointless. It is not antioxidant for the essential oil, only for skin. However, in wash off products? No point. Change it for “normal” Tocopherol.

I was hoping more Betaine would thicken the soap as well. I tried salt but found little difference.

Iselux Mild - 75%
Cocamidopropyl Betaine - 25%
Glycerin - 1%
Citric Acid pH 6-7
Phenoxyethanol - 0.6
Essential Oil - 0.2% for fragrance

GeorgeBenson said:

I have used Iselux Ultra Mild and did not find salt to work very well to thicken it. Iselux SFS on the other hand is very easily thickened with salt.

I have had success using HPMC, Polyquaternium-10, and Sorbithix to thicken. There are many PEG-type thickeners too such as crothix but I haven’t used those.

Xanthan will thicken but I find even the soft grade does give it an undesirable (to some) texture as well as making it harder to rinse off.

Also, just using a higher percentage of ultra mild will make for a much thicker soap.

Thank you, I think I will definitely try with methocel and polyquat-10. I am already using a super high conc of iselux, anything beyond this would be out of budget.

I have used iselux before and had no problem. The challenge this time is to make the 10% concentrate instead of the regular 30-40%.
ketchito

Member
February 16, 2022 at 1:25 pm

@Cosmetic_Chemist Did you try with Crothix Liquid? It’s very useful for hard to thicken formulas, and at not so high dose.

I don’t think adding more Betaine would help since it doesn’t necessary have the same viscosity building response with all anionics.
Abdullah

Member
February 16, 2022 at 2:49 pm

Is 0.6% phenoxyethanol enough as preservative?
1Armand2

Member
February 19, 2022 at 11:32 pm

Abdullah said:

Is 0.6% phenoxyethanol enough as preservative?

Yes that’s enough
ketchito

Member
February 21, 2022 at 1:53 pm

@1Armand2 I believe @Abdullah‘s comment was if Phenoxyethanol as sole preservative was enough. Phenoxyethanol lacks activity against mold and yeast, and that’s why it’s usually paired with organic acids.
1Armand2

Member
February 22, 2022 at 4:16 am

ketchito said:

@1Armand2 I believe @Abdullah‘s comment was if Phenoxyethanol as sole preservative was enough. Phenoxyethanol lacks activity against mold and yeast, and that’s why it’s usually paired with organic acids.

Correct!
PhilGeis

Member
February 22, 2022 at 11:56 am

Not only will phenoxyethanol not cover fungi and Gram positive bacteria well enough - if diluted 1:10 as you indicate, you’ll have only 600 ppm - and inadequate level in any case.

Will you have the consumer dilute?
emma1985

Member
February 26, 2022 at 4:53 am

I recommend Crothix for thickening liquid cleansers. So much nicer than Xanthan, and you only need 2% max. It’s a bit expensive though.

Sepimax Zen can work as well, depending on the type of surfactants you’re using (it’s anionic.)
Cosmetic_Chemist

Member
March 2, 2022 at 4:33 pm

UPDATE:

Crothix is too expensive and even after 10% desired viscosity was not achieved.

Thank you for your recommendation on the preservative system, we are still exploring other options and will be sure to remember your comments!

I am still waiting on the Phosphate thickener and will let you know if that or any other material works!

Thank you!
Rockstargirl

Member
March 3, 2022 at 3:01 pm

Are you ok with adding a little SLS? It will thicken with iselux