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UV block
Need some advice here. I was making UV block samples and tried several times but always found oil separation or oil coming out. below is my formulation, what is my problem and how to improve it. dont want to fail again. Many thanks!
Aqua 39% C941 0.4% 1.5%Montanov 5% N82 Vit E 2% F350 2% SL13.2<42.9% 3.2% Lecithin 1% 1.2%G57<11% 3.2% Shea Butter 3%UV Cut ZNO 20% Silsoft 895 5% Phyto Celltec 0.1% EDTA 0.5% -
13 Replies
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Take out Carbomer and you can try Veegum HV or Veegum Plus or Laponite or HEC or Xanthan.
BTW I really can’t make a head or tail of what you have written, I could see only the 20% ZnO and that Carbomer 941. -
why u write them in trade name? write their INCI name to see what are they
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I agree w/ @nasrins - formula you posted is useless w/o INCI names
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My appologies. I am sending below my INCI list and pls give me your advice. .this is a spf35cream.
Carbomer 0.4% Cetearyl Alcohol / Coco glucoside 5% Mineral Oil 2% DIMETHICONE 2%
Glycerin / Inulin Lauryl Carbamate 3.2% Sodium polyacrylate /C18-C21 alkane /trideceth-6 1%
(Shea Butter) Butyrospermum Parkll 3% Zinc Oxide / Cyclopentasiloxane / PEG-10 Dimethicone 10%
PEG-17 Dimethicone / Polyalkylene Oxide 5%
Malus Domestica Fruit Cell Culture Extract/Xanthan Gum/ Glycerin/ lecithin/ Phenoxyethanol 0.1%
Glycerin / Aqua / Alcohol / PEG-40 Hydrogenated Castor Oil / Tocopherol / Vitis Vinifera (Grape) Seed Extract 2%
TOCOPHERYL ACETATE 0.125%
Titanium Dioxide 0.7% Pentylene glycol 4% Iodopropynyl Butylcarbamate 0.175%
Zea Mays（corn）starch / Titanium Dioxide / Sucrose / Iron Oxide / Hydroxypropyl methyl Cellulose 0.8%
Triethanolamine 0.2%
many thanks
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Unless there is a highly effective “SPF booster” in there I am missing, I don’t think you’re going to be able to achieve SPF 35 with that level of actives.
Looks like ~6% ZnO and ~1-1.3% TiO2. Good rule of thumb for a very rough SPF prediction would be 0.7-1.0 SPF unit per 1.0% ZnO and 2.0-3.0 SPF units per 1.0% TiO2.Assuming of course you are using UV grades and not pigmentary grades. -
thanks a lot. 6%ZnO n 1 - 1.3% TiO with your rule, it works out roughly spf 10.8 only. where am i wrong?
Also what is your adv of my formulation, how to avoid so much “oil” coming out from the sample? what is my problem?
would highly appreciate your advice. many thanks
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Daniel,
To get an SPF of 30+ you’re going to need at least 7.5% TiO and 5% ZnO.If you’re oil is separating out, you likely do not have enough emulsifiers in your formulation. Have you done an HLB calculation on your oils and emulsifiers? -
a really helpful tool which I use as a guide is the BASF calculator https://www.sunscreensimulator.basf.com/Sunscreen_Simulator/
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I would second Marks observations here. You either don’t have enough emulsifier(s) or you do not have the correct blend of emulsifier(s).
If you haven’t estimated the required HLB for your oil phase, then that would be a good place to start. Also, if you still plan to use that ZnO dispersion, you’ll have to factor in the extra silicone from there as well (D5). -
You have any suggestions of emulsifiers to add and which silicone to reduce? thanks again
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u mean SPFbooster uv filters?
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should be UV filters.
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You have any suggestions of emulsifiers to add and which silicone to reduce? Or how to improve my formula? appreciate much your help.
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