Tuesday, April 26, 2011

HLB system: Let's get slightly more complicated

The one down side of using the HLB system is that you have to figure out the HLB of the oil phase if you change an ingredient (unless you're substituting one vegetable based oil for another one, but even then jojoba could throw you off because it's 6.5, fractionated coconut oil is 5.5, and emu oil is 8, although that's not a vegetable oil, is it?).

The other down side is that it's hard to find information for some of our esters. There's some great information in the PDF to which I keep referring (and you really should have downloaded by now if you want to play along). So let's take a look at what happens when we take a recipe - let's use yesterday's - and mess with it by changing the oils, adding some esters and silicones, and adding some fatty alcohols. (This won't be considered minimally processed for much longer!)

25% water
10% aloe vera
10% chamomile hydrosol
10% witch hazel
2% hydrolyzed protein
5% tamarind seed extract
3% glycerin
0.5% allantoin

10% soy bean oil
7.5% cocoa butter
7.5% mango butter
7% emulsifier*

0.5% chamomile extract
0.5 to 1% preservative
1% fragrance or essential oil blend

Let's say you want this to be a drier feeling body butter. We'll keep the 7.5% mango butter (HLB 8), but let's add a few esters to the mix. I think I want some isopropyl myristate at 2% (HLB 11.5) and I'll add 3% cetyl alcohol to thicken the product (since I took out the cocoa butter, it will be thinner), which has an HLB of 15.5. I think I'll include 5% C12-15 alkyl benzoate (HLB 12) and 5.5% cetearyl ethylhexanoate (HLB 8.22). And finally, I think I'll go with dimethicone at 2% in the cool down phase (it's listed as 5, but there's some debate about this. Click on this post for more information).

Okay, so where are we? We didn't change the amount of the oil phase - it's still 25% of the total recipe (we don't include the emulsifier because we're trying to replace that) - but we've changed the HLB dramatically!

Remember the steps to finding out the HLB of your oil phase...

1. Which ingredients have an HLB value?
Mango butter, isopropyl myristate, cetyl alcohol, C12-15 alkyl benzoate, cetearyl ethylhexanoate, and dimethicone.

2. How much of each ingredient is in the recipe?
Mango butter - 7.5%
IPM - 2%
Cetyl alcohol - 3%
Dimethicone - 2%
C12-15 alkyl benzoate - 5%
Cetearyl ethylhexanoate - 5.5%
Total oil phase = 25%

3. Divide the amounts by the total oil phase to find out how much each makes up in the oil phase.
Mango butter - 7.5/25 = 0.30 or 30%
IPM - 2/25 = 0.08 or 8%
Cetyl alcohol - 3/25 = 0.12 or 12%
Dimethicone - 2/25 = 0.08 or 8%
C12-15 alkyl benzoate - 5/25 = 0.20 or 20%
Cetearyl ethylhexanoate - 5.5/25 = 0.22 or 22%

4. Multiply the percentage by the HLB value. Add them together to get the HLB value of your oil phase.
Mango butter - HLB 8 - 0.30 x 8 = 2.40
IPM - HLB 10 - 0.08 x 10 = 0.80
Cetyl alcohol - HLB 15.5 - 0.12 x 15.5 = 1.86
Dimethicone - HLB 5 - 0.08 x 5 = 0.40
C12-15 alkyl benzoate - 0.20 x 13 - 2.60
Cetearyl ethylhexanoate - 0.22 x 8.22 = 1.8084

So the required HLB of this oil phase is 9.8684.

1. Find a low HLB emulsifier and a high HLB emulsifier.
I'll go with glycol distearate (HLB 1) and ceteareth-20 (HLB 15.2) for one combination and glyceryl stearate (HLB 3.8) and oleth-10 (HLB 12.4) for another.

2. Work on the percentages to find a total that is very close to the HLB value of your oil phase.

50% glycol distearate (0.5) + 50% ceteareth-20 (7.6) = 8.1. Too low.
40% glycol distearate (0.40) + 60% ceteareth-20 (9.12) = 9.52. Still too low.
38% glycol distearate (0.38) + 62% ceteareth-20 (9.424) = 9.804. Close enough!

If we're using 4% emulsifiers in this recipe, we'll need to use 1.52% glycol distearate (4% x 0.38 = 1.52%) and 2.48% ceteareth-20 (4% x 0.62 = 2.48). If we want to use 5% emulsifiers in this recipe, we'll need to use 1.9% glycol distearate (5% x 0.38 = 1.9%) and 3.1% ceteareth-20 (5% x 0.62 = 3.1%).

50% glyceryl stearate (1.9) + 50% oleth-10 (6.2) = 8.1. Too low. 
40% glyceryl stearate (1.52) + 60% oleth-10 (7.44) = 8.96. Still too low!
30% glyceryl stearate (1.14) + 70% oleth-10 (8.68) = 9.82. Just about right! 

If we're using 4% emulsifiers in this recipe, we'll need to use 1.2% glyceryl stearate (30% of 4% is 1.2 - 0.3 x 4 = 1.2) and 2.8% oleth-10 (70% of 3% is 2.8 - 0.7 x 4 = 2.8). 

If you want more practice, try figuring out how you'd use something like PEG-100 stearate (HLB 18.8) and glycol distearate (HLB 1) or polysorbate 80 (HLB 15) and glycol distearate (HLB 1) or any other combination of high and low HLB emulsifiers! 

What does our recipe look like now? (And remember to increase your water amount if you've removed anything from the oil phase. We took out 2% of the previous emulsifier, so we need to increase the water to 27%). 

27% water
10% aloe vera
10% chamomile hydrosol
10% witch hazel
2% hydrolyzed protein
5% tamarind seed extract
3% glycerin
0.5% allantoin

7.5% mango butter
2% IPM
3% cetyl alcohol
5% C12-15 alkyl benzoate
5.5% cetearyl ethylhexanoate
5% emulsifier (1.9% glycol distearate and 3.1% ceteareth-20 or 1.2% glyceryl stearate and 2.8% oleth-10)

2% dimethicone
0.5% chamomile extract
0.5 to 1% preservative
1% fragrance or essential oil blend

Join me tomorrow for one more post on HLB emulsifiers before we get back to duplicating! 


Tara said...

So since there is no HLB value for BTMS (or it can't be found), or rule of thumb for its use, we should use it according to our preference of thickness?

melian1 said...

do we ever use more than 2 emulsifiers in a combination? or is the two just for ease in explaining it and not frightening us into passing out?

re the btms question, i have in my notes the following: "The HLB calcs are only for nonionic emulsifiers and will not work for other types of emulsifiers, cationic's, anionic's, alkyl lactylates etc. "
so btms would be irrelevant?

Susan Barclay-Nichols said...

Hi Tara. The HLB of BTMS-50 is estimated at 15.5 and Polawax at 14.9, but these are kind of irrelevant because they are all in one emulsifiers and we don't need to calculate a required HLB for the oil phase for them.

Hi Melian. You're right - for non-non-ionic emulsifiers, we aren't calculating the HLB, but some anionic ingredients behave as non-ionic emulsifiers and we'd use a theoretical HLB number for those. It gets kinda complicated. I can post a couple of interesting PDFs if you want to learn more!

melian1 said...

i'm finding disagreements on the hlb of a few oils. how do we know what is the correct value? specifically,:
Mango Seed Butter 8
Mango (Mangifera Indica) Seed Oil [RHLB = 7 ± 1]

Meadowfoam Seed Oil 6.5
Meadowfoam (Limnanthes Alba) Seed Oil [RHLB = 6 ± 1]

Myristyl Myristate 8.5
Myristyl Myristate [RHLB = 7.52 ± 1]

Jojoba Oil 6.5
Jojoba (Buxus Chinensis) Oil [RHLB = 6 ± 1]

Cyclomethicone 7.75
Cyclomethicone [RHLB = 7.5 ± 1]

how do we choose?

melian1 said...

there are more. on your blog you said that squalane was 12 to 12.9 ( http://swiftcraftymonkey.blogspot.com/2009/11/squalene-vs-squalane.html )... another source said it is 7 plus or minus 1. is squalane like lecithin and varies?

also, is lanolin 10 or 12? the pdf you cited says 10 but http://www.zenitech.com/documents/hlb_english.pdf says 12.
how do we know who to believe?

Mozartiana said...

Hi Susan!
I recently purchased pistachio butter and I was wondering could you tell us something more about its features/benefits? And perhaps, give a suggestion how to use it in a best way in a recipe for body cream? Thanks!

Susan Barclay-Nichols said...

Hi Melian. Normally, we'd use 2 emulsifiers in combination, but you could add a third if you wanted. There are some situations in which we see lecithin thrown into a product, and that might be for extra emulsification.

I've attempted to answer the rest of your great questions in this post! Click here (although it's really long!)