Friday, August 30, 2013
Gels (revised for 2013)!
What's the deal with gels?
Carbopol Ultrez 20 gelling agent (INCI: Acrylates/C10-30 Alkyl Acrylate Crosspolymer), which you'll see in the ingredient list of a lot of gelled products, like hair gel or aloe vera gel. I've written about this before, so I'll refer you to that post for more information.
In short, we get this gelling agent wet then add a really alkaline thing - an 18% lye solution or triethanolamine - which turns it into a gel. We can use this gel on its own to make a gelled product, like a hair gel, or use it in a lotion to give a more cushiony feeling.
Take a look at a commercial lotion you like. Odds are pretty good that you'll see a carbomer in there. It offers a moistened, cushiony feeling to that lotion.
CREATING A GEL WITH CARBOPOL ULTREZ 20 (THICK GEL)
96.8% distilled water
1.2% Carbopol Ultrez 20
1.6% 18% lye solution or triethanolamine
0.4% liquid Germall Plus (or preservative of choice)
Why include a preservative in the gel? Because I made a big batch and wanted to save it. If you are planning to use what you make and not save it, don't worry about preserving it in gel form. You'll be adding preservative to the final product in which you use it in that case. If you do preserve it and add it to something later, don't worry about having too much preservative. Lots of things we use have preservative added to them - specifically, ingredients that contain water like surfactants, proteins, and so on - and we don't run into issues with over-preserving there.
Are the preservatives we find in our ingredients enough to preserve a product? (No.)
It is pretty important to use distilled water here as we don't want any salts or metals from tap water in the mix as it can mess up the viscosity.
Please write something like "lye solution" and a skull and crossbones on any container with lye because it looks like water and doesn't really smell like anything other than water. But it can hurt if you spill it on yourself.
An exothermic reaction is one that produces heat. An endothermic reaction requires heat. I always remember is that I have to put heat "endo" an endothermic reaction, and that heat "exos" an exothermic reaction.
Put your container back on the scale and add your neutralizer. Mix really well. It should thicken in a few seconds, but it might take up to a minute. Mix ing by hand is sufficient, although you can use some kind of device, if you want.
This version of gel - 1.2% carbomer to 1.6% neutralizer - will create a thick gel. If you want a thinner gel, add less carbomer say 0.9% carbomer to 1.2% neutralizer. You'll have to play around to find that ratio you like.
It works out to about 3:4 ratio of carbomer to neutralizer. If you want a thicker gel, use more of each. Want a thinner gel? Use less of each.
Related posts about gels:
Gels: Ooey gooey fun!
Gels: Aloe vera
Gels: Surfactant-y fun
Gels: Hair styling gel
Gels: Make a gel based toner
Related posts on gel-like things that don't use carbomer, but instead use Amaze XT or gums:
Amaze XT: Making detanglers
Surfactants: Building viscosity (scroll down for Amaze XT information)
Facial scrubs: Working on our surfactant base (part 4)
When to add ingredients (part 2)
Experiments in the workshop: Min-maxed toner becomes facial gel
Iron Chemist results: LSB
We'll get to some comments Saturday and Sunday and come back to gels on Monday! It'll give you time to think about what you'd like to make! (I'm working on a liquid eye liner sealant, and I should have some information about what people think by then!)