Toner Formulation

Hi I am developing a toner with alcohol, sodium lactate, propylene glycol, salicylic acid, benzalkonium chloride and Peg-40. The problem is after the solution mix there is a small white precipitate form. How to get rid of that? I am not sure but I think that is salicylic acid but I am sure that it is completely dissolve with the alcohol phase. 

Comments

  • I think there is incompatibility between sodium lactate (anionic) and benzalkonium chloride (cationic). 

    Changing the order of addition may get rid of the reaction but may still pose stability challenges. You can try getting rid of either, or reducing their concentrations (or that of either) and see.
  • Thank you @Abbass_1 ; I will try to remove benzalkonium chloride. But it is used to prevent the inhibit the growth of bacteria in products. Can you recommend for alternative? Thanks! 
  • hi @Abbass_1 i tried to remove the benzalkonium chloride but still there is a white precipitate in solution after.

  • What is the % of your alcohol? Salicylic acid is highly insoluble in water. I think you mixed your toner with water. This is the reason that precipitate formed. Decrease your SA ( Salicylic Acid ) content or increase your alcohol content but it might be too astringent. For around 14% of SA to dissolve, it needs pure ethanol
  • It's the salicylic acid. What is the % of SA? You don't need the alcohol. I've had success dissolving 2% SA in 10% PG with or without heat. I forget how much water I added, but I initially got some precipitation until I titrated the water down to a certain amount.
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