Home Cosmetic Science Talk Formulating Why didn’t my lotion thicken properly?

  • Why didn’t my lotion thicken properly?

    Posted by erindlea on January 25, 2015 at 10:18 pm

    As a cosmetic scientist with a home-based business, I have successfully produced many gallons of lotion over the last four years using a combination of aloe vera juice, glycerin, low and high HLB emulsifiers, butters, oils, and optiphen plus as my preservative. Yesterday I (somewhat presumptuously) substituted a refined coconut oil in place of my usual EV organic coconut oil because of a limited supply of the good stuff, and my lotion, upon cooling to room temperature, is only slightly more viscous than water. What happened? I heated and held the water phase at 160F for 20 minutes, I combined and shear mixed the two phases once they were both at this temperature, I added the optiphen once the mixture was below 100F, and I have a perfectly stable emulsion. It is just the wrong viscosity. I noticed that the coconut oil contains TBHQ (antioxidant), citric acid, and dimethylpolysiloxane (antifoaming agent). Is one of these the culprit? I dread the idea of reheating the lotion to add more thickeners and potentially volatilizing some or all of the phenoxyethanol in the process, but this may be my only solution. Does anyone have any suggestions for salvaging my watery lotion?

    Bobzchemist replied 9 years, 4 months ago 6 Members · 7 Replies
  • 7 Replies
  • crisbaysauli

    January 26, 2015 at 12:19 am

    One suggestion maybe is adding a post-emulsion thickener like Sodium polyacrylate (Covacryl MV60). Coconut oil is a little problematic to handle really.

  • belassi

    January 26, 2015 at 2:56 am

    it’s the dimethylpolysiloxane. Your coconut oil was designed for the chip pan.

  • Chemist77

    January 26, 2015 at 3:48 am

    Try Sepigel 305 or Dow Corning RM 2051 or Rapithix A60 although my personal choice would be Sepigel 305 because of the feel and the body/structure it provides to the formula. 

    Just hoping that you don’t have any cationics.
  • Bobzchemist

    January 27, 2015 at 2:36 pm

    On a production level, I would make new batches and blend-off about 10-20% of the bad batch each time. If you are selling this, your consistent customers will notice the difference if you fix the batch any other way.

    The only way around this, in my opinion, is to make it a new product. It’s water-thin, so it could be a sprayable emulsion. Or, you can add a sensorial thickener to give the product an unique feel, and sell it in a different package.
  • OldPerry

    January 27, 2015 at 3:00 pm

    Yes, if you’re selling the product you can’t add a new ingredient to thicken it unless you change the ingredient listing on your label.  Blending off as @Bobzchemist suggested is your best option.

  • erindlea

    January 27, 2015 at 4:05 pm

    Thanks, guys. I like Bobzchemist’s blend-off or new product idea. I definitely don’t want to change the labels to include a new ingredient, and I don’t want to alter the feel of the product since I have a loyal following for my original formula. I may blend off part of it and experiment with the rest using some sodium polyacrylate that I have on hand.

  • Bobzchemist

    January 27, 2015 at 6:30 pm

    @erindlea, you’d be surprised at how discerning a regular customer can be. Sometimes, something you’ll think is a minor change will stick out like a sore thumb…

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