Home Cosmetic Science Talk Formulating Stick deodorants - sodium stearate compatibility

  • Stick deodorants - sodium stearate compatibility

    Posted by LuisJavier on July 16, 2020 at 11:59 pm

    I am aware that mono/di-propylene glycol and water can be thickened by sodium stearate, but is there another substrate that can be used aside from these? 

    LuisJavier replied 3 years, 9 months ago 4 Members · 9 Replies
  • 9 Replies
  • LuisJavier

    Member
    July 16, 2020 at 11:59 pm

    Maybe glycerin works, I can try it. Hopefully it doesn’t feel too sticky upon application. Still looking for another alternative however. 

  • natiyo123

    Member
    July 17, 2020 at 12:27 am

    you mean another gellant or solvent?
     
    I made one with glycerin, it works

  • letsalcido

    Member
    July 17, 2020 at 3:00 am

    @LuisJavier I made one with PG (~90%) and Glycerin (4%) and it was too sticky. I hated it.

    Propylene glycol is a humectant itself, I don’t know that glycerin will provide any benefits that PG alone won’t.

    The bar was also way too hard. I used 5% sodium stearate, lowered it to 3% later and now it’s good but I did remove Glycerin at the same time, so not sure if glycerine had a role in the hardness of the bar.

  • LuisJavier

    Member
    July 18, 2020 at 9:34 pm

    @letsalcido One reason for a preference on glycerin over MPG specifically (not DPG) is due to the lack of skin irritation. I’m aware that high concentrations of MPG in a stick deodorant can possibly result in rashes on the underarms of some individuals, unless it’s another ingredient or a combination (which I doubt). 

  • LuisJavier

    Member
    July 18, 2020 at 9:38 pm

    @natiyo123 I’d appreciate another recommendation as the gellant or solvent though I was initially looking for the name of another solvent I can use that will not cause irritation/rashes like MPG (monopropylene glycol) can. My concern over using a high concentration of glycerin is a sticky feel. I’d prefer to make an at least partially water-based solid stick deodorant. 

  • chemicalmatt

    Member
    July 22, 2020 at 4:31 pm

    Most low MW glycols may be used, only with varying results, as others have noted. Gycerin is too sticky as they said. Butylene glycol works and brings down the tack and irritation (but you still need PG). I always added a little alkanolamide ( alas, cocamide DEA worked best) to aid propel-repel and maintain translucency to please the marketing peeps. As for gellants, nothing I know works better in that system than sodium stearate and you must use the right grade too: OP-100 from HallStar. 

  • LuisJavier

    Member
    July 23, 2020 at 11:26 pm

    @chemicalmatt ah I really hoped I could have used another solvent besides MPG that is cheap and avoids the problem of irritation. Besides glycols, I wonder what that may be. Yes, I’ve tested sodium stearate quite a bit and it’s gelling ability at even low concentrations is impressive. I buy mine from mistral; I don’t know what you think about their quality. Is there an alternative to Cocoamide DEA as I’ve read that there are safety concerns regarding this one or the MEA type and what do you mean by propel-repel? 

     
  • natiyo123

    Member
    July 24, 2020 at 8:40 am

    Hi, usually these sticks are made with MPG or DPG, to avoid the irritation you can add more water and add more preservative/antimicrobial to compensate increase of water 

    check out this patent they list a variety of ingredients to be used for a gel stick deodorant 

    https://patents.google.com/patent/US9307821B2/en

  • LuisJavier

    Member
    July 24, 2020 at 12:12 pm

    @natiyo123 seems like the patent shows propanediol (1,3 propylene glycol) utilised instead of propylene glycol (1,2 PG). I’m aware that people report no irritation using propanediol, though this is a considerably more expensive ingredient.

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