Monday, May 28, 2012
Emulsifiers: Ritamulse SCG
When using this ingredient, you want to heat and hold your water and oil phases, then add the water phase to the oil phase in a thin stream. They suggest mixing it until it reaches 30˚C. I have found that I can mix it for a few minutes after combining the two phases, leave it a bit, add my cool down phase, then mix it further and still have a really stable product. (I have lotions from March 2011 that are still very stable, despite the slight rancidity of the oils.)
Do not add your cool down phase until you reach 45˚C or lower. I tried adding my cool down at around 49˚C, and I had separation within a few minutes. It turned into a cottage cheese looking product! So gross!
Ritamulse SCG doesn't play well with acidic ingredients, like AHA or lactic acids, and it's not great with cationic ingredients, so you don't want to include any cationic polymers or cationic compounds, like Incroquat CR, cetrimonium chloride, cetrimonium bromide, or Incroquat BTMS-50.
I've found conflicting information on this - some things say it is substantive and works well with cationic ingredients, others say not to use cationic ingredients with it. My experience has been that cationic polymers have caused separation almost immediately upon addition, so I'm going to suggest either trying it yourself or not using cationics. (Normally I would add my cationic polymers to the heated water phase, but I thought perhaps having them in the cool down phase might help to avoid separation. I was wrong. It separated almost immediately! It was so awful!)
The data sheets for this emulsifier claim that it is a good moisturizer - and I can't see a reason why that wouldn't be true as most of our emulsifiers offer moisturizing to our products - and a good humectant. What I've read indicates that sodium stearoyl lactylate doesn't pick up water as readily as other humectants, but it will hold on to it more tenaciously than other humectants, especially in low humidity environments. I have found it has quite a nice skin feel, although it does have a little waxiness to it, probably from the cetearyl alcohol.
As an aside, sodium stearoyl lactylate was originally created to be an emulsifier in baked products, specifically those that are yeast leavened. It's starting to get a bad name in foodstuffs - for instance, I've seen a bread recently advertising that it doesn't contain sodium stearoyl lactylate as an emulsifier - so I'm finding it interesting that it's being considered so natural in the bath & body community. See this link at Skin Deep - they consider it a 1, which considered of low concern (although they don't seem to have much information on this ingredient, so I wonder how they came to that conclusion).
HLB value of 3.8 =/- 1 and sodium stearoyl lactylate has an HLB value of 6.5 and a melting point of 47˚C to 53˚C. Ritamulse SCG has an HLB value of 3.5, but it behaves like it has an HLB value of 9.0.
What the heck does this mean? HLB values under 9 indicate that the ingredient is lipophilic, or oil loving. HLB values over 11 indicate the ingredient is hydrophilic, or water loving. HLB values of 9 to 11 indicate the ingredient is a bit of both. So Ritamulse SCG has an HLB value that should mean it is a lipophilic or oil loving ingredient, but it behaves as an intermediate ingredient with a bit of each.
Although all the components of Ritamulse could be animal derived, the company assures us in its data bulletin that all of the ingredients are plant derived.
Ritamulse SCG is sold under a number of different names, depending upon the supplier. You might see it as Ecomulse, Natramulse, Emulsimulse, and so on. I suggest learning the INCI name above and shopping for it that way. You can get it at quite a few suppliers - visit the FAQ to see if you can find a supplier near you.
Quick summary of Ritamulse SCG emulsifier
INCI: Glyceryl stearate (and) cetearyl alcohol (and) sodium stearoyl lactylate
Suggested usage rate: 2% to 10% in the heated oil phase.
Should emulsify up to 25% oils.
Not a good idea to use cationic ingredients with this emulsifier.
pH range of 5 to 7.5.
Special considerations: Add the water phase to the oil phase in a thin stream, and mix until it reaches about 30˚C.
Join me tomorrow as we have fun formulating with this emulsifier!