Magnesium Hydroxide and Deodorant Processing

Hello friends, 

We are experiencing some quality issues with a natural deodorant that I thought I would throw out to everyone to see what their thoughts were. 
Current issue is the stick are setting up to be very soft/ mushy/ sticky and adhering to the dome of the component after about 72 hours.   We have exhausted all the options of playing around with pour temp and cooling tunnel temperatures during the filling process. We have now moved on to investigating the raw materials and processing instructions. 

We found the highest melt point of the waxes in this formula is 70c, we have been heating to 87c (this formula was given to us, we did not develop it)  We are currently trialing reducing this temperature to 72°c to alleviate any possible structural damage that might be incuring. Waxes used are stearyl alcohol, beeswax and some jojoba esters. 

We also use magnesium hydroxide and arrowroot powder as our starches.  My questions are the following: 

1. Does anyone know if heating to 87c is possibly causing the structure of the waxes/ arrowroot powder to be compromised? We found the peak gelatinization point of arrowroot powder to be 72c. 

2. Does anyone know if the magnesium hydroxide (Trade name CareMag) needs to be added at a higher temperature or would you see no problem incorporating it at the newer lower temperature of 72 ? 

3. Does anyone have any other possible suggestions that may be causing the soft/ mushy sticks we are seeing ? 

Any help is greatly appreciated!  

Thank you so much! 
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Comments

  • GraillotionGraillotion Member
    edited November 10
    I would say it is improbable that your waxes are damaged with an 87C temp (think candles), however you did not mention which waxes you used.

    I think your mag is just in suspension, and also not influenced by those temps.

    One could try something like a non-gelling starch (distarch phosphate), even if just as a knockout.  Who knows...maybe you'll find (like I did) what an awesome starch it is.  Much of the gelling of starch....depends on length of time at temp.  Hence bigger batches will gel worse than smaller batches.  (Otherwise...rice starch has about the highest gel temp of the natural starches.)

    If you do have to start over....I'd sure reconsider your clients skin, and eliminate the high pH ingredients. :) 


  • chemicalmattchemicalmatt Member, Professional Chemist
    @Monty Other than pinning this problem back on the client who "formulated" it, not much you can do without DEL/ADD other ingredients. The starch and MgOH2 are in suspension as Graillotion mentioned, as this is anhydrous (correct?), so your problem is with stearyl alcohol. Subbing ceresine or microcrystalline wax for C18OH will help immensely, and adding a little polyglyceryl ester will keep it from mushing too, but they insist on you using their formula right? My question is: what the heck is suspending those solid-state "active" powders? Not that either is actually deodorizing anything, mind you, but during a hot-fill operation you need some yield value to maintain suspension while filling and cooling. See: quaternium-18 hectorite in most suspensoid antipersiprants having the dreaded aluminum-zirconium active ingredients.

  • @Monty Other than pinning this problem back on the client who "formulated" it, not much you can do without DEL/ADD other ingredients. The starch and MgOH2 are in suspension as Graillotion mentioned, as this is anhydrous (correct?), so your problem is with stearyl alcohol. Subbing ceresine or microcrystalline wax for C18OH will help immensely, and adding a little polyglyceryl ester will keep it from mushing too, but they insist on you using their formula right? My question is: what the heck is suspending those solid-state "active" powders? Not that either is actually deodorizing anything, mind you, but during a hot-fill operation you need some yield value to maintain suspension while filling and cooling. See: quaternium-18 hectorite in most suspensoid antipersiprants having the dreaded aluminum-zirconium active ingredients.

    im interested in this too, why is stearyl alcohol a problem?
  • mm starch will not gelatinize without water, sometimes in my case it burns a little but it doesnt affect the "Mushiness" of my stick

    i dont think it matters the temp at which u add the magnesium as long as the rest is melted

    I would try adding solid emulsifiers or beeswax
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