Thanks.
I ended up using 25% anionic and a total of 25% amphoteric out of 100% of the formula.
If I can sum up the problems of formulating a shampoo, it's that you have to think in three dimensions.
Imagine a tent supported by a pole and two laterals.
Ideally you want to use as much amphoteric as you can because that's refatting, 100% biodegradable, green, non irritant.
The problem is that it's the anionic that makes the foam.
Then, you've got to adjust the pH to 5 - 5.5, so you need to add citric acid. By the time you get to the required pH, the viscosity is way too low - you're off the rhs of the salt curve. The way to fix that is to increase the amount of anionic in the formula until you get the right viscosity. As you approach it, the addition of even tiny amounts of anionic makes dramatic changes.
It went like this:
Mixed the three amphoterics and the water, took it up to 70C, added the anionic, measured the pH: 8.5 (thick)
..added sufficient citric to move the pH to the required 5, (thin now)
..added, by small amounts, sufficient anionic to improve the viscosity.
..measure pH again. still about 5. OK.
..proceed with addition of other ingredients.
I used panthenol, hydrolized keratin, aloe vera, glycerine, quaternium-60, and BB's blackberry fragrance solubilized in Polysorbate-20. It smells lovely and fresh. This is a clear shampoo; the polysorbate did the job perfectly. I've given out a few samples to friends.
Login
Register
FAQ
Search
