Monday, September 28, 2009

More fun with the HLB system - a body butter recipe.

All right, so we did a kinda basic recipe yesterday, let's look at something more complicated...a body butter filled with various oils and esters and silicones.

OUR MODIFIED BODY BUTTER RECIPE
WATER PHASE
42% water
10% aloe vera liquid
10% lavender or rose hydrosol
2% sodium lactate

OIL PHASE
10% oils - 5% macadamia nut and 5% safflower oil
15% butter of choice - I'm using mango butter at 15%
4% emulsifier - to be determined
3% cetyl alcohol
2% IPM

COOL DOWN PHASE
0.5 to 1% preservative
1% fragrance or essential oil blend
2% cyclomethicone
2% dimethicone

What's in the oil phase and how much do we have?

Macadamia nut - 5% - HLB: 7
Safflower oil - 5% - HLB: 8
Mango butter - 15% - HLB: 8
Cetyl alcohol - 3% - HLB: 15.2
IPM - 2% - HLB: 11.5

Don't forget the silicones in the oil phase!

Silicones are tricky things in that there could be various HLB values for them. As a rule of thumb, cyclomethicone is about 8 and dimethicone is 9 or 10, depending upon the centistokes. The higher the centistoke, the higher the HLB. Since I normally use 350 c.s., which is a low c.s. dimethicone, we'll consider this a 9. (If you don't know the c.s. on your dimethicone, ask your supplier. If you can't do that, the thicker the dimethicone, the higher the c.s. If it's like corn syrup, it's likely a higher c.s. If it's like water, it's likely a lower c.s.)


Special note: Please read this post on silicones and the HLB system. I'm going to suggest you use 5 as the required HLB value for dimethicone. I'm not re-doing this math, and the recipe does work with dimethicone at 9, but if you want to use the HLB system for your own recipes, you'll probably want to use 5 in the future.

Cyclomethicone - 2% - HLB: 8
Dimethicone - 2% - HLB: 9

The oil phase is 34% of the recipe, so we need to figure out the percentages in our oil phase.

Macadamia nut - 5/34 = 0.147 or 14.7% of the oil phase
Safflower oil - 5/34 - = 0.147 or 14.7% of the oil phase
Mango butter - 15/34 = 0.441 or 44.1% of the oil phase
Cetyl alcohol - 3/34= 0.088 or 8.8% of the oil phase
IPM - 2/34 = 0.0588 or 5.9% of the oil phase
Cyclomethicone - 2/34 = 0.0588 or 5.9% of the oil phase
Dimethicone - 2/34 = 0.0588 or 5.9% of the oil phase.

Check your total. Yep, it equals 100%!

So we have our numbers - now multiply those by their HLB values

Macadamia nut - 0.147 x 7 = 1.029
Safflower oil - 0.147 x 8 = 1.176
Mango butter - 0.441 x 8 = 3.528
Cetyl alcohol - 0.088 x 15.2 = 1.338
IPM - 0.0588 x 11.5 = 0.6762
Cyclomethicone - 0.0588 x 8 = 0.4704
Dimethicone - 0.0588 x 9 = 0.5292
Total HLB for the oil phase: 8.7468 - we'll round this up to 8.75 or 8.8.

So our HLB target number for the emulsifiers is 8.8.

The HLB for glycol distearate is 1.
The HLB for ceteareth-20 is 15.2.
We know from yesterday that a 50-50 mix of these emulsifiers will give us 8.1. But we need 8.8 so we can't just use yesterday's numbers. Darn!
We're working with 4% total emulsifiers.

So if we use 55% ceteareth-20 (0.55 x 15.2 = 8.36) and 45% glycol distearate (0.45 x 1 = 0.45) we will get an emulsification system with an HLB of 8.81. Perfect!

So we know we need 2.2% ceteareth-20 and 1.8% glycol distearate to make this body butter work!

Click here for an Excel spreadsheet that might help with the HLB system!

Join me tomorrow for more fun with emulsifiers!

7 comments:

Mich said...

Okay, I'm confused (what else is new, LOL)...

Here you have the HLB requirement for dimethicone as either 9 or 10, depending on c.s. It is listed as 5 on both LabRat's PDF and the Herbarie's list. (Neither of those specify the c.s.)
Am I missing something here?
Is there a better/more definitive list out there than these?

Thanks for explaining all this, Susan! You are the best!

Mich said...

Oh, Susan, now I'm getting myself even more confused...

I looked at your water-based makeup remover posting and tried to figure out the HLB numbers for it. Suppose for the 15% water-soluble oil you use a 3:1 blend of olive oil and polysorbate 80. From what I figure, the HLB requirement is 7, but the HLB value for the poly 80 is 15. What am I doing wrong? Aren't those numbers supposed to be closer?

Maybe this is all too much for a Monday...I'm usually pretty math savvy.

Thank you for listening to my crazy questions!

Susan Barclay-Nichols said...

Hi Mich. Great question! I've written a post on the topic - here. Talk about a challenge for first thing in the morning!

You always make me think!!! Thanks so much!

Susan Barclay-Nichols said...

For something like the water based make-up remover, you aren't going to be using the HLB system. This system is specifically for non-ionic lotions, so it doesn't apply to things like make-up removers or shampoos or conditioners or other things to which we can add emulsifiers but aren't considered lotions. (For instance, when adding a fragrance oil to an anionic shampoo you can add some polysorbate 20 - HLB 16.7 - without worrying about the HLB values of either the shampoo or the emulsifier.)

If we wanted to turn our make-up remover into a non-ionic lotion - or more of a milk, given the amount of water we have - you'd want to use the HLB system.

So we have 15% oil - let's say olive oil at 7 - our oil phase has a total HLB of 7 (because olive oil is the only oil). So we'd want to get an HLB system that brings us to 7.

We could use poly 80 (15) and glycol distearate (1) at 43% poly 80 (6.45) and 57% glycol distearate (0.57) for a total of 7.02. So we'd add this at 2 to 4%, heat and hold, and we'd have a make-up remover lotion.

And these aren't crazy questions! You're making me think. That's a good thing!

Lomond Soap said...

These posts have been a great help, I'm starting to understand the HLB system (I think).
Many thanks
Corrie

Jodi said...

Hi Susan,

How did you know to use 4% emulsifier in this recipe? From my understanding of your other posts about 8% polawax, maybe 9% eWax and 7% BTMS-50 should be used. (…because the total oils (34%) times .25 is 8.5%) How do you know 4% emulsifier will be enough?

I’ve (finally) moved from anhydrous formulations to making lotions! It is so enjoyable and satisfying. Thanks for sharing so much with us. I especially love your recipes for thick foot creams and body butters!

Jodi

Susan Barclay-Nichols said...

Hi Jodi! Check out the previous post to see how I arrived at it. The short answer? It is a number suggested by a skilled cosmetic chemist from the Dish forum.