EDTA , viscocity - Chemists Corner

Formulating

EDTA , viscocity

Posted by Aanchal on December 30, 2019 at 2:44 pm

Can EDTA affect viscocity at 0.1% given that it is a salt ? (In an aqueous surfactants system) . Will it be effective as a chelator in lower amount? How low will do?

I am not using salt in my formulation but know that one of the raw materials already has some salt. I was using EDTA in lower amount earlier. I tried at 0.1% and the viscosity dropped.

chemicalmatt replied 1 week, 4 days ago 6 Members · 11 Replies
11 Replies

EVchem

Member
December 30, 2019 at 8:02 pm

what is giving your product viscosity?
OldPerry

Member
December 30, 2019 at 8:20 pm

Yes, EDTA can affect the thickness of a system if the thickening effect is a result of surfactant micelle packing or acrylic polymers. If it is a system thickened with something like HEC then it won’t have much impact.

ngarayeva001

Member

December 31, 2019 at 12:42 am

I guess it’s a matter of amount because I use 0.2% of Disodium EDTA in several formulas with Aristoflex AVC, which is utterly sensitive to electrolytes, but I haven’t noticed any adverse effect.

Here is an example:

INCI	%
Aqua	85.75%
Disodium EDTA	0.20%
Betaine	2.00%
Butylene Glycol	3.00%
Propanediol	1.00%
Germall Powder	0.20%
Cetearyl Isonononoate	5.00%
Dimethicone 10	1.00%
Tocopherol	0.10%
BHT	0.05%
Pemulen Ez4U	0.20%
Aristoflex AVC	1.30%
Bisabolol	0.20%

There are no other thickeners but Aristoflex and Pemulen and both don’t tolerate salts. I think I should make two identical formula with and without EDTA and compare, but my point is that even if it has an effect it’s minor because it’s quite a bouncy and fluffy gel even with 0.2% of EDTA.

Aanchal

Member
January 4, 2020 at 1:21 pm

Thanks @Perry !
Aanchal

Member
January 4, 2020 at 1:24 pm

@ngarayeva001

I used hardly 0.1% but it lowered the viscosity. In my case, I know there is salt in one of the items in my formula. So the EDTA adds up to the already present salt.
Aanchal

Member
January 4, 2020 at 1:24 pm

@EVchem

SLES
EVchem

Member
January 7, 2020 at 8:14 pm

@Aanchal So it’s like Perry is saying, you are doing the traditional surfactant +salt to thicken and EDTA will contribute to that. You might have to reduce salt (cut down on your ingredient w/ salt) or increase SLES

I’ve made one basic cleanser a while ago, base was something like:

Water qs
Tetrasodium EDTA 0.05
Sodium Methyl Cocoyl Taurate 30% 5
SLES 70% 15
Citric acid qs
Salt 2.5
preservatives/ marketing fluff qs

You can do a salt-curve analysis to find where your formula is thickest
Aanchal

Member
January 8, 2020 at 1:13 pm

Thanks a lot @EVchem.

Yes, I had done a salt curve analysis and was sticking to the amount that served best. I had to re-do it when I changed my CAPB supplier, and realised it already has salt and needed no additional salt.

As regards EDTA, with the salt already present, I am not able to use it in my formula amount (0.1%) but doing fine in much lower amount.

You have mentioned citric acid qs, even that affects viscocity, what limit do you put for that?

I have to finish the big batch of CAPB lying in the inventory, may have to continue with the same brand as well (economical). What lowest percentage of EDTA serves as chelator?
EVchem

Member
January 8, 2020 at 6:35 pm

@Aanchal I see. CAPB and SLES are supposed to be a match like peanut butter and jelly so maybe you just need some minor adjustments.

The citric acid is there partially as secondary chelator and to keep the pH ~7. In that specific formula it was <0.1%.

I’m not sure how much chelator is needed, I think it would depend on the other ingredients and the metal burden. The theoretical calculation is probably too involved and might not carry through perfectly to application. my guess is that standard 0.1% is more than enough, without testing for free heavy metals you’re really just looking for the chelators to help formula stability
Fekher

Member
April 24, 2024 at 11:22 am

I’am working for making balsam with<div>

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Water qsp

Citric acid : to ph 4.5 or lower

Cetearyl alcohol 5%

CATC 5%

Perfume 0.3%

Preservative 0.1%

Edta: 0.1%

I see lot of formulation with lower level of Cetearyl alcohol and CATC and thicker all formulation seen without edta so my suspect that EDTA is the main reason to not get thick balsam.

So is my guess right? Then any explanation for that phenomenon?

@Perry44 @chemicalmatt @Abdullah @Paprik @Cafe33 @ketchito others

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chemicalmatt

Member
April 25, 2024 at 8:07 am

@Aanchal If we assume CATC is cetyltrimethylammonium chloride (CETAC as we know it) the means of thickening that low solids formulation is NaCl, just plain sodium chloride salt. Add into the batch as a 20% solution at 40C and you will be surprised how much viscosity you will gain. This is the reason all those inexpensive hair conditioners on the market appear to be much richer than they are.