Monday, June 8, 2015
Why did my lotion fail? Emulsifiers
Every emulsifier comes with information on how to use it, like how much to use, when to use it (heated oil phase, heated water phase, cool down phase), what it can emulsify (vegetable oils, silicones, esters, etc.) to name a few things. For instance, Sucragel AOF can't emulsify silicones or non-natural oils, while Incroquat BTMS-50 is great at silicones. Check the suggested usage for your emulsifier with your supplier and make sure you're getting the one you want.
Emulsifiers may require other things to make them work. Something like Polawax is an all-in-one emulsifying system that works without anything else, but something like ceteareth-20 requires a low HLB emulsifier to work while glyceryl stearate would require a high HLB emulsifier to work. Check with your supplier to ensure what you are getting is what you want!
Note: All the emulsifiers I list below are all-in-one emulsifiers that are suitable for oil-in-water lotions. When it comes to water-in-oil lotions - like cold creams - you will have to find other emulsifiers, like borax and beeswax.
Polawax is generally my go-to emulsifier because it seems pretty much foolproof. Just use enough and make sure you heat and hold, and you've got yourself a lotion. It doesn't have any restrictions about what emollients it could emulsify. When we use Polawax, we want to use it at 25% of the oil phase of the product.
10% olive oil
5% mango butter
3% cetyl alcohol
This oil phase totals 20%. We want to use 25% Polawax, so we would multiply the 20% by 0.25 and get 5%. So we are using 5% Polawax for this oil phase. Using a little more wouldn't be the end of the world, but we definitely don't want to go under.
Note: This 25% rule ONLY applies to Polawax. It doesn't apply to any other emulsifier. Check out this post on why I might use more or less Polawax in a creation.
If you're using emulsifying wax NF, the general rule is that you would use 25% of the oil phase, plus one. So for the recipe above, you'd use 6% e-wax.
Incroquat BTMS-50 is another fairly foolproof emulsifier that works with any oils, butters, or other emollients you might want to use. (Make sure you are getting BTMS-50 and not BTMS-25 as the latter isn't a great emulsifier! Read the INCI to make sure!) There isn't a hard and fast rule about how to much to use in a product, but I generally use slightly less than I would with Polawax as it thickens the product quite a bit. If I were to use 5% Polawax for the oil phase above, I would use 4% to 5% BTMS-50.
As I mentioned above, Incroquat BTMS-50 is fantastic for emulsifying silicones. The data bulletin shows a recipe emulsifying 20% silicones with 3.5% BTMS-50.
Ritamulse SCG can be a bit tricky as there are some restrictions on what you can use with it. You should not go over 25% oil soluble ingredients total - check out this post to see the epic lotion fail! - and you can't use cationic or positively charged ingredients like honeyquat with it. Do not even think about adding your cool down phase before it hits 45˚C as that can lead to another epic lotion fail.
The usage suggested for Ritamulse SCG is 6% to 8%. I tend to use the higher amount to ensure a good emulsification.
Lotionpro 165 is a new emulsifier for me, and steadily becoming one of my favourites! It's usage rate is suggested at 2.5% to 5% for up to 30% oils. It works well with AHAs and BHAs, and is suggested for facial moisturizers. It tends to make thinner products than those made with the previous three emulsifiers, so you might need to add some cetyl alcohol or stearic acid to boost the viscosity.
Montanov 68 is a liquid crystal emulsifier. The suggested usage is 1% to 5%, and it is suggested to use it at 25% of the oil phase. For this one, you want to mix it with a stick blender, not a mixer. This emulsifier can be hard to preserve, so you will want to choose a preservative that works well with hard-to-preserve lotions, like Germaben II or Phenonip.
Olivem 800 is used at 1 to 3% if used with a co-emulsifier, and 2 to 5% as the primary emulsifier. It must be heated and held in the oil phase for use. It is suitable for oil free products and very light lotions.
Olivem 1000 is a liquid crystal emulsifier. The suggestion is to use 2% to 3% for light fluid lotions where the Olivem 1000 is the only emollient in the oil phase, 4% to 5% for 5% to 25% oils, and 6% to 8% to be a self emulsifying system. It's suggested that we use glyceryl stearate at 1% to 2% in the oil phase or xanthan gum at 0.2% or carbomer at up to 0.1% in the water phase to increase stability. It's also suggested to use cetearyl alcohol as the fatty alcohol in the oil phase.
Heat and hold your water phase at 70˚C and your oil phase to 70˚C to 75˚C. Add the oil phase to the water phase, then mix with high shear mixer, like a stick blender for this. Mix until the emulsion is formed, then a few minutes or so, then walk away until it reaches the cool down phase, then briefly mix again. I've seen it suggested that you mix the post-cool down phase lotion by hand as it is possible to overmix this lotion. It can take up to 24 hours for it to reach its final viscosity.
I've read that this emulsifier isn't a big fan of proteins and some hydrosols can cause clumping.
Side note: I have never had success with this emulsifier and have given up trying. If you want more information on it, please check out the comments in the linked post as people have offered great information on it!
Sucragel AOF is a liquid emulsifier that can be used cold. As I mentioned above, AOF cannot be used with esters, mineral oils, or silicones. It works with ingredients that are pH 4 to 8. You don't want to go over a 25% oil phase. And you must use your ingredients in the proper order! This makes very light lotions that are slightly sticky, so I suggest adding a thickener like cetyl alcohol or stearic acid to the product to increase viscosity.
Join me tomorrow as we continue to take a look at emulsifiers!