Sodium Laureth Sulphate 26.5% and Electrolytes

Formulating

Sodium Laureth Sulphate 26.5% and Electrolytes

Posted by mkproddev on April 10, 2014 at 3:36 am

Hi,

we currently use Sodium Laureth Sulphate 26.5% in our hand wash products and thicken with salt to around 4000 - 5000cP. Recently we have had some problems with high viscosities (about 2,000cP over spec). Looking at the product specification for SLES, there is < 0.5% Sodium Sulphate by mass in there.

If we receive a delivery of SLES that contains 0.1% Sodium Sulphate, then receive a delivery that contains 0.5% Sodium Sulphate that equates to a variable between 1Kg to 5Kg Sodium Sulphate between deliveries once scaled up into a batch of product.

So could this variable be causing the viscosity problems with Sodium Sulphate being an electrolyte? Has anyone ever had this problem before?

Thanks.

mkproddev replied 10 years, 3 months ago 4 Members · 8 Replies
8 Replies

Chemist77

Member
April 10, 2014 at 9:36 am

then the best way is to cut down on salt and check the viscosity.
mkproddev

Member
April 10, 2014 at 11:46 am

Thanks for your reply milliachemist.

If we reduce the salt in all our formulations it will reduce the viscosity as expected. The problem is, if our next delivery of SLES has low Sodium Sulphate content (0.1% rather than 0.5%) then the viscosity of the hand washes would decrease anyway because there are less electrolytes. So I would have to increase the salt in the formulations again. That is my thinking anyway. I will get some Sodium Sulphate and add it to one of our formulations on a lab scale to see if the viscosity increases.

I was just wondering if anybody had any experience or knowledge of Sodium Sulphate increasing viscosities in anionic systems. Thanks.
Bill_Toge

Member
April 10, 2014 at 4:15 pm

how much SLES and salt have you got in this formula?
DavidW

Member
April 11, 2014 at 12:23 pm

We never out salt into the formulation itself. This is one of the reason. It will always vary from batch to batch. Even the salt we get causes differences.

We always look up the amount we used last time and start a little lower and adjust till we get it right. Does your spec have a sufficient range ?
mkproddev

Member
April 14, 2014 at 4:18 am

Hi Bill,

they’re just basic hand wash formulations. We use about 6.5% Active SLES and about 3.5% Salt to thicken.

Hi David,

Interesting that you adjust from batch to batch. Might be something we need to adopt in future, it’s just a pain adjusting, re-sampling, re-testing etc. Our spec is 4000cp +/- 500cp.
mkproddev

Member
April 14, 2014 at 4:18 am

Hi Bill,

they’re just basic hand wash formulations. We use about 6.5% Active SLES and about 3.5% Salt to thicken.

Hi David,

Interesting that you adjust from batch to batch. Might be something we need to adopt in future, it’s just a pain adjusting, re-sampling, re-testing etc. Our spec is 4000cp +/- 500cp.
DavidW

Member
April 14, 2014 at 7:19 am

If you are checking viscosity in-house it isn’t really a pain, not for us. Our ranges are usually more than 500 cps. Typically at least 1,000cps spread.
mkproddev

Member
April 14, 2014 at 11:23 am

Yes we’re testing in house, de-aerating a sample and conditioning it to 20C for testing can take up to 20 mins, so adjusting, remixing and re-testing a couple of times is wasting valuable production time.

We’ve found that there are other ingredients such as betaine with varying NaCl levels (up to 5%) so this will also have an affect. Might have to determine NaCl content on raw materials in future and adjust formulations accordingly so they pass first time. Thanks for your help.