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working with PBSA
Hi, I’m trying to formulate a day cream with SPF50+ that has a more day-cream-like texture than sunscreen… So I am trying to include PBSA in order to reduce the greasyness of the formula as I am working with the BASF simulator to quantify the filters (I have no chance of additional testing until the formula is finished) . The thing is I am being asked for a jar-packed-formula and I can´t seem to stabilize or thicken any formula containing PBSA. I’ve found that ExpertGel® EG412 works better than Pemulen TR-1 polymer but still cant find the proper ratio. I also need for the cream to be whitish (if possible), no nano (not even organic filters), no octocrylene, no homosalate, no silicones (if possible), no PEGs…. A mindbreaker.
It would also be helpful if someone has noticed any ingredient incompatibilities (preservatives, other filters…) or seen if it is possible to work in w/o formulas with this filter…
Any advice would be grateful.
Thanks!!
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2 Replies
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There is a disconnect here: are you formulating a w/o sunscreen emulsion here? If so, I don’t expect any of the rheology modifiers you mention to work well if at all. Neither the urethane (ExpertGel) nor the acrylic (Pemulen) will build viscosity. Both must have a carbomer partnered with it to build viscosity so just add 0.50 - 1.0% Synthalen K (carbomer) with Pemulen TR-2 - which handles up to 40% oil load, twice that of TR-1 - and make this an o/w emulsion. Add 1.0 - 2.0% cetyl alcohol and some silky sensorial esters and you are done. PBSA is totally compatible with the anionic acrylics.
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No, I was actually working on a O/W, I will try the tips you suggested and see how it goes. The W/O was another option I was considering in order to try and build thickness, but I was just curious if it would work with PBSA as I haven’t seen any market references containing this filter in those type of emulsions.
Thank you for the tips!
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