Opaque shower gel

Dear all,
 I am asking for your recommendations to remedy a quality defect in an opaque shower gel.
This shower gel has a defect in settling of the opacifier at the bottom of the bottle
The analysis of the causes of this non-conformity led us to the following causes:
1- The quality of our opacifier is very sensitive to salt. So we reduced the% salt, but the non-compliance still persists.
We changed the quality of the opacifier to a more stable one with a nonionic surfactant (coconut glucoside) but the non-compliance still persists.
2- The perfume contains a solvent (terpenes) which promotes the non-stability of the opacifier. The perfumer was invited to reformulate his perfume.
In the meantime, I am trying to find a solution to correct the non-conforming batches.
It's possible?
Is there anyone who can help me?
Thank you


  • @Tyss Which type of opacifier are you using? Styrene/acryltes opacifiers are sensitive to eectrolytes, but they don't settle; rather, they go to the top. Stearate based opacifiers are not salt-sensitive, but they require some specific type of suspending agents (like Carbopol's, for instance) and high viscosity. If you're using a suspending agent at good level, and you have high viscosity, then you should chenck your surfactant/polymer system, which can (and that's very common) be sensitive to electrolytes.  
  • Dear Ketchito,
    I previously used the opacifier: styrene acrylate copolymer (see technical sheet) and for the correction, I used the opacifier: styrene acrylate copolymer & coco-glucoside (see technical sheet)
    With the two qualities of opacifier, we observed the same phenomenon hands with the second, the phenomenon is delayed.
    Can the perfume with terpene be the only source of the appearance of settling phenomenon and can be remedied or not?
  • Bill_TogeBill_Toge Member, Professional Chemist
    in a previous job I have seen styrene/acrylate copolymer type opacifiers settle in the presence of excessive salt; our solution was to source an opacifier that was more robust towards salt, namely Rohm & Haas/Dow's Opulyn 305

    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • @Tyss I agree with @Bill_Toge, you might need to search for a less sensitive opacifier, like Opulyn 305 mentioned above. You could also try with a stearate based opacifier (although, you'd need a suspending agent for this). 

    Alternatively, you could try a sample without opacifier, to see if the issue persists; if it does, then it's rather your surfactant/polymer system the one being sensitive. I don't believe terpene from the fragrance is responsible for the phenomenom, but you could do a knock out test for this one as well. 
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