Saturday, August 3, 2013
Weekend Wonderings: Thickening a liquid soap with Crothix, a new surfactant thickener, solubility of allantoin, heating shrink bands,
We held craft group outdoors to play with some fragrances, and the kids made these amazing fragrance misters with all kinds of neat scent combinations, most of which I'll be posting over the next few weeks. It's an easy recipe - up to 2% fragrance oil, up to 2% polysorbate 20 (equal amount to the fragrance oil), 0.5% to 1% preservative, and the rest in distilled water. Thanks to Voyageur Soap & Candle for donating something like 200 of these little misters! The kids had a blast!
modifying a conditioner into shaving lotion, Michael asks: If I am using all natural products and crothix how should I formulate? I am using water, organic castille soap, vegatable glycerin, baking soda (sodium carbonate), essential oil, macadamia nut oil, olive oil, germall, and liquid crothix 1%. How long do you mix crothix for? My product was watery. I'm going to use tap water next time. I used alkaline water for this batch. I want the consistency to be a little thicker. It's too runny when it comes out of the foam bottle. Do you add crothix by w/w or by v/v? I added crothix by total volume of formulation. so my total volume was 620 mL and I added 6.2mL of crothix (1%)
Crothix won't work with liquid soap as it needs a pH range of 5.0 to 9.0, and castille soap has a pH of about 10. A soap has to have a pH of 8 or higher - alkaline - in order to be a soap. If you reduce the pH below 8, it de-saponifies and becomes a bunch of oil and water again. (Click here to see what happens if you mix vinegar - an acid - and castille soap together. Ick!) You could reduce the pH slightly to something like 8 or 9 with some citric acid, for instance, but you'll need a pH meter to see where to stop.
As an aside, I saw spellings for castille with one l and with two. I am choosing the two ll version - castille - but would like to hear from Canadians if this is the spelling we use.
Please don't use tap water because you don't want to worry about the metals found in it that can mix with your product. Always use distilled water so you don't have to deal with anything other than a nice neutral - around pH 7 - solvent.
Everything we do is by weight, never by volume. You might have used 1% Crothix by volume, but that isn't 1% by weight. I can't find the specific gravity of Crothix - how much it weighs per millilitre - but it isn't going to be 1 ml equals 1 gram. If you have something like water - which is 1 gram per 1 ml - at 99 ml and you add 1 ml Crothix, you don't have 1% Crothix. You could have 0.5 grams of Crothix or 1.5 grams of Crothix.
So the short answer is that you can't use Crothix with this product unless you lower the pH, and you can't really lower the pH without ruining the castille soap, so I'm afraid I don't know what to suggest about thickening it. And we always do everything by weight because it's more accurate.
Ritathix DOE thickener (INCI: PEG-120 Methyl Glucose Dioleate, Methyl Gluceth-10), a thickener that is supposed to be able to thicken non-ionic surfactants like decyl glucoside. I can't find a data sheet on it anywhere as it seems like it was just introduced in mid-June, but I did find this suggested recipe using this ingredient from Personal Care Magazine. I will be trying this out during my two weeks of holiday at the end of this month!
From Happi: Applications: Surfactant systems, facial washes, cleansers
Use Levels: 0.5-3.0%
Comments: A liquid based surfactant thickener that has the ability to thicken in very precise increments. A cold process ingredient that can be added during any phase of the manufacturing process and can be used to fine tune batch viscosity. Can be used in clear surfactant systems and does not need to be neutralized.
Chemistry Friday: Why do we care about mixing and solubility?, Clare asks: I dream of making The Ultimate Moisturiser for my grumpy pernickety skin. Everywhere says that allantoin can be used up to 2%, but if the solubility at room temperature (and all products are going to end up at room temperature) is only 0.57%, surely it's impossible to use more than that? Why is the usage rate always stated as up to 2%? How do we know that other extracts or actives are soluble up to their maximum usage rate? I don't want to spend lots of money on lovely ingredients only to waste them if they won't dissolve at the recommended usage. Can you help explain?
I think the reason we might see it suggested at up to 2% is that this isn't just about solubility in water. Allantoin is more soluble in glycerin and SLS than water (see this brochure). Lotioncrafter also has a great PDF on the topic with some suggestions about how to use it at more than 0.5%.
We don't want to waste our ingredients adding more than we should, but you will be using them up a lot faster than you expect! I think facial moisturizers are the hardest things to make because it really is about getting a good base recipe and tweaking it quite a lot, so my suggestion is to make 100 gram batches and not anything larger, adding one thing to each batch so you can isolate a certain ingredient. Use each product for at least ten days as it can take quite some time to know whether our skin likes something or not. If you have any serious reactions, stop immediately.
Let us know how the moisturizer turns out!
A couple of notes about acne, break outs, and sensitive skin
Comedogenicity: What the heck does that mean?
Weekend Wondering post, Maiti asks: I've recently begun making lotions based upon your recipes. Thank you for everything that you do! My question is this: I am worried about customers at farmer's markets opening my lotion jars and sticking their dirty fingers in my product. I'm switching to flip-top bottles in my next set. But for now, I've got screw-top jars. I want to shrink wrap them to keep people out. But that requires heat from a hair dryer to shrink the plastic wrap around the jar. Will that affect the lotion?
I don't think it will, but I also don't sell my products, so it's something I haven't tried. Given these shrink bands are intended for this very purpose, I would think those things would be accounted for by the manufacturer. Looking at these shrink bands from Voyageur Soap & Candle, they mention shrinking them with a heat gun without mentioning any cautions, so I would think things are fine. You aren't exposing it to a lot of heat for very long, so my instinct is to tell you not to worry too much as long as you are heating it just long enough to shrink the band.
Experienced vendors - what do you think?
Join me tomorrow for more Weekend Wonderings!