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Stearic acid, KOH and Carbomer
Hello all,
i would like to ask you for guide how to proper neutralize stearic acid and Carbomer (Carbopol® Ultrez 30 Polymer ) in cream. So for neut. 1g of stearic acid i need 0.21g of KOH.
Question is, do i mix KOH in oil phase or do i mix it in water phase, before i combine it with oil phase? Also the KOH will react to carbomer (Carbopol® Ultrez 30 Polymer), do i need to put more KOH because of that, or will neutralize stearic acid anyway?Regards
Greg
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2 Replies
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@Rencelj - check out “Dr Straetmans Standard Formulary” pdf - 2009, 2011, 2012 - use GOOGLE to search. Has formulas that include polymer, Stearic acid and KOH (they give the solution as 10%) and the method to put it together.
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Rencelj, always add the KOH or NaOH or whatever alkali to the batch after mixing oil/water phases, above 65C, the more dilute, the better off you will be. ANd, yes, you must factor for neutralizing/saponifying both acid contributors. Since KOH is sold (world-wide) in a 40% liquid form, this makes the job easy. Your ratio of 5:1 is not based on solid state, which would be more like 18:1. For the Ultrez, you may use approximately 1 part 40% KOH to 8 parts Ultrez 21, just as a rule of thumb .
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