Cleanser with Ammonium Lauryl Sulfate

We have been asked to duplicate a product on the market that uses ALS as the primary surfactant and Disodium Cocoamphodiacetate as the secondary. Total solids in the formula is 11% and it also has HEC and carbomer in the listing, as well as extracts and glycerin.

I admittedly don’t have much experience with ALS as it’s an older surfactant but have worked out some good ratios with the amphoteric for thickening... and even tried other amphoterics with good thickening while it is in process. I have also tried several ratios of HEC and carbomer to provide yield, because no matter what, batch thins down within a couple days, tops. It also happens if I leave carbomer out or reduce HEC to nothing.

Other items are less than 2% total - Glycerin, Propanediol, extracts. I have also tried several preservatives - Spectrastats, PE9010. It also happens if I leave the preservative out just to observe.
 
I have never had this happen to me, not even with sulfate free formulations.

Is something causing the ALS to thin? Process? Grade of raw materials (30% active ALS)? Anyone familiar working with ALS, I appreciate it!

Comments

  • ALS will release NH3 at high pH.
    Please check your pH if it is higer than 5.5.
    Also, please use pH buffer for stabilizing the product.
  • ALS will release NH3 at high pH.
    Please check your pH if it is higer than 5.5.
    Also, please use pH buffer for stabilizing the product.
    pH is good - at 5.5. What is the most appropriate buffer for ALS?
  • PerryPerry Administrator, Professional Chemist
    It would help if you gave us a listing of all the ingredients you're using and even better with the percentages. 

    Are you using salt? That can affect viscosity. Are you neutralizing the Carbomer? How much HEC are you using?
  • chemicalmattchemicalmatt Member, Professional Chemist
    @RawMaterialGirl...what Perry said, especially what item exactly describes "Carbopol"?  I assume you are using Aqua SF-1 or an analog since straight carbomer would crash immediately. HEC would also not be my first choice for rheology stabilizer either; Hydroxymethylcellulose (Methocel) works better in this system. (Don't be fooled by label content) Finally, if your solid-state ratio of ALS to amphoteric is close to 1:1  at pH 5.0 - 6.0, and you build with an alkanolamide (e.g. cocoamide DIPA) you should not need a rheological modifier at all. 

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