[Jennycat]

EVchem said:

You don’t really need the Sodium Benzoate do you? It’s activity diminishes drastically as pH rises, I think above 5.5 it is functionally useless. I don’t know if that’s interacting with HEC but might as well take it out.

Thank you @EVchem! That’s a great point. I have the impression that even at neutral pH Sodium Benzoate would provide some anti-fungal and anti-mold effect. I made a batch without Sodium Benzoate and I will see if that would help.

[Jennycat]

chemicalmatt said:

Depending on what’s in that surfactant blend, Jenny, it does not appear obvious what would do that. I’ve had viscosity drops with HEC and proteins, enzymes and other amino acid derivs but HEC is generally pretty robust as you know. Leucidal once dropped a cleanser formula built with HEC; that has enzyme qualities is all I could figure. 

Thank you Matt! We do have some amino acid derivatives for claim purposes. This is very interesting and I’ll need to keep that in mind when I formulate.

[Jennycat]

Thank you for your response!

Yes I did disperse HEC in cold water then activate it with alkali ingredients, and the viscosity was achieved to 4000 cps after batching, which is desirable for our product (the surfactant blend does not thicken much). However when it sits in chamber it’s slowly losing its viscosity, therefore I am wondering if some sort of hydrolysis would happen at pH 6-7.

PE82 is 80% phenoxyethanol and 20% ethylhexylglycerin.

chemicalmatt said:

Did you activate it with a tiny bit of alkali? Try it after wetting out at high-speed for at least 30 minutes and you’ll see it gel. You are dispersing the HEC into the RT water at the start, before adding anything else, correct? If not, that would be the problem too. Also, what is PE82???  

[Jennycat]

There are various grade of hydroxyethyl cellulose, so they behave differently.

The delayed-hydration version as a coating for easy blending, and you will need to adjust pH to 8-10 to thicken it.

[Jennycat]

Only PQ-10 thickens.

I think it depends on the concentration of PQ-10. I’ve used 100% PQ-10, which thickens at 0.3%. There is also diluted version, which is easier to work with, but it is 10% concentration, so 3% of this version is needed to achieve the same effect as the 100% one.

[Jennycat]

There are liquid carbomers that are easier to work with. Eg. Carbopol AQSF-1

[Jennycat]

Hydroxyethylecellulose, and carbopol AQSF-1

[Jennycat]

We are paring phenoxyethanol with sodium benzoate, and ehtylhexylglycerin.

[Jennycat]

I’ve used both PQ-7 and PQ-10. PQ-10 also helps to increase viscosity a little.

[Jennycat]

AOS and CAPB should work.

[Jennycat]

I’ve used Xanthan Gum to stabilize a emulsion at low percentage. The final emulsion is still spray-able.

[Jennycat]

Is the pH the same before and after adding the parabens? Some acrylate thickener might be thickened by increasing pH.

[Jennycat]

It depends on what you want, since you are formulating a car shampoo it seems that B is better.

In my opinion, “luxury foam” is more like small thick bubbles that last a longer time, not necessarily a higher foam height, and it is usually for personal care.

[Jennycat]

The judgement of forming performance would depend on your purpose and claim. 
For example:
If you are targeting “easy-rinse”, then B is a better option;
If you are targeting “luxury foam”, then A is a better option.

[Jennycat]

For sulfate-free shampoo, AOS+CAPB/Hydroxysultine+Cocamide MIPA can be thickened by salt.

I have also had success formulating sulfate-free shampoos thickened by cellulose thickeners and carbomers. One thing to note is cellulose thickeners can be instable to some surfactants and causes phase separations.

[Jennycat]

Hi Curlycorner,

I’ve seen similar things in some of my formulations!

How did you add the cellulose thickener? We found that if we add it upfront and have proper mixing until there is no “fish-eye” like chuncks before adding in surfactants would help with the separation. Another thing that seemed to help is using warm water (60 °C) to disperse the hydroxyethyl cellulose. 

[Jennycat]

This is super helpful information!!! Thank you so much!

Did you have to add a thickener in addition to a higher surfactant concentration?

ozgirl said:

I have definitely seen Phenoxyethanol drop the viscosity like that in surfactant formulations. We had to reformulate our products when we changed from MCI/MI preservatives.

You may need to increase your surfactant concentration. We achieve a viscosity of around 4000 with a ALS/CAPB/Cocamide MEA blend and a phenoxyethanol based preservative so it is possible.

Just remember that adding too much salt can also cause a decrease in viscosity.

[Jennycat]

Thank you! The thiazolinons were truly a poor choice, and I’m glad that we are making the change to another preservative system that works better and cause less irritation.

However the viscosity drop really bothered me to move forward. Considering phenoxyehtanol such a common preservative these days, I am just curious if anyone has seen it before or have seen similar phenomenon or have a solution for it.

Belassi said:

Almost anything you add affects the viscosity. I should also advise, your original choice of preservative is horrible, don’t risk being sued by clients when their skin erupts.

[Jennycat]

Hi asafvarlix,

Thank you so much for your reply! I was using 1% of phenoxyethanol, or 1% of benzyl alcohol.

I was using up to 20% of a blend that contains 40% of SLES and 15% CAPB. I’ll try to boost it up a little more but the budget won’t allow me to add much more.

I am wondering if adding sequence would play a role? Most of the time I add the preservatives in the end, especially when I use hot water to blend methyl cellulose in the formulation.

asafvarlix said:

Dear jenny,
1. you’re not mentioning HOW MUCH phenoxyethanol you are using.
i know it’s common to use between 0.5%-1.1%.  are you using more?

2.how much SLES you are using?  my experince shows that if you use too little, the formulation is very weak and sensitive to problems such as you mentioned.