Second opinion on dissection of liquid lipstick LOI & Isododecane solubility question

Hi everyone!

I'm Skylar and I'm new to the forum. I'm recently started a biochem track, but I've been getting more interested in cosmetic chemistry so I'm trying to learn as many practical skills as possible before finishing school. My question is a bit long-winded so please bear with me!

I've been reverse engineering different powder products pretty easily, but I'm challenging myself with a liquid matte lipstick. This is the LOI in order and the percent by weight concentrations I've worked out as a possible starting formula:

Isododecane - 52%
Trimethylsiloxysilicate - 17%
Cyclopentasiloxane (siloxane D5) - 12.25%
Dimethicone - 2.75%
Synthetic Beeswax - 3%
Disteardimonium hectorite - 2-3%
Kaolin - 2%
Hydrogenated Polyisobutene - ?
Silica Dimethyl Silylate - 2%
* <1% line (0.2-0.4% I'd assume)
Propylene Carbonate 
C10-18 Triglycerides
Ethylhexyl Methoxycinnamate
Tocopheryl Acetate 
Phenoxyethanol
Caprylyl Glycol
Ethylhexylglycerin
Hexylene Glycol

In my research I pulled formulas from Kobo and ran across a blog post by a consultant who was reverse engineering the same product, but I disagreed with her assessment so I wanted to get a second opinion.

She removed some of the fluff from the formula (hydrogenated Polyisobutene, replaced kaolin with synthetic fluorphlogopite, etc.) and seemed to overlook the order of dimethicone and cyclopentasiloxane. She put dimethicone at 15% and said the cyclopentasiloxane content was from Bentone Gel (propylene carbonate and disteardimonium hectorite suspended in cyclopentasiloxane) at a concentration of 5%.

I think it's wholly possible that Bentone Gel is included, but, given the order of ingredients, my assumption is that this is actually dimethicone (>200) in cyclopentasiloxane. The non-volatile dimethicone would act to modify the evaporation rate of the cyclopentasiloxane and help with the formation of a film, right? Since that's generally at a ratio of 85/15 that would explain its placement in the LOI, as well.

Also, if I want to finish this out and test my version, I don't have access to Bentone Gel or synthetic fluorphlogopite (but, honestly, I would use silicone treated titanium dioxide because this is a matte formula and that will suspend and add opacity better). Could cyclopentasiloxane with dimethicone/vinyl dimethicone crosspolymer serve as a suspension and viscosity agent in the same way disteardimonium hectorite would?

If that isn't viable, there's a hectorite gel formula that's a suspension of stearalkonium hectorite and propylene carbonate in caprylic/capric triglyceride. I think I could incorporate that to the wax in the final phase, BUT are triglycerides soluble in isododecane even though they're not really hydrocarbons? It seems really basic, but I'm unsure. If not, I'd assume you'd need a high shear mixer....

Anyway, those are my crazy long questions! I appreciate any input!


Comments

  • Can't answer to all questions but as per my modest experience with lipsticks (I only got into them several months ago), elastomers like cyclopentasiloxane/vinyl dimethicone crosspolymer or dimethicone/vinyl dimethicone crosspolymer don't contribute to viscosity and quite hard to suspend (at least without special equipment which I don't have). What they actually do is they make formula more matte.
    You can buy small amount of synthetic fluorphlogopite here https://www.glamourcosmetics.it/it/ronaflair-soft-sphere . Boron nitride and silica give the "soft focus" and matte effect but but I don't know what synthetic fluorphlogopite contributes to the formula. I didn't really noticed any difference when I added it.
    Also Cyclopentasiloxane content might be from this product:
    https://www.glamourcosmetics.it/it/gc-resin-tc

    It's Trimethylsiloxysilicate and cyclopentasyloxane.

    And as a user I would agree that removing kaolin is a good idea. I can say there is kaolin in the lip product without even looking at the LOI. It gives quite an unpleasant dry feel.
  • SkylarkSkylark Member
    edited July 15
    @ngarayeva001 thank you! This is so helpful!

    First of all, I speak way more Italian than I thought, so my uncle would be pleased, Haha! But, the resin TC product you shared with me has some great information (from what I could read)! It confirmed that Trimethylsiloxysilicate and Cyclopentasiloxane are used together in high concentrations (this one is 45-50% resin content, so it's, basically, a 1:1 ratio and I think it said it can be used from 10-40% by weight) in lipstick, foundation, eyeliner, etc. to create a film that's long lasting and improves color. More importantly, the combo is oil dispersible!! So, I think I can use the capric triglyceride-based product without a homogenizer.

    Also, same! Kaolin is great but I don't want it anywhere near my mouth. I understand the mattifying use but it has such a chalky and drying feel that, even in small concentrations, I feel you have to do a lot more to offset that. So it isn't super functional to me in this formula. I'd maybe even go for Nylon-12, Boron Nitride, Silica...something to improve overall slip and bounce, idk.

    At any rate, thank you, and if you're learning about lip products, too, I'll share my findings. I definitely need to adjust the percentages a bit, but I'm going to experiment more.
  • @Skylark, I don't speak a single word in Italian, but google chrome kindly offers to translate pages on foreign languages :)

    I am new to lipsticks, and only tried to make stick versions (maybe I will get into liquid one day). I used that Trimethylsiloxysilicate and Cyclopentasiloxane blend and I like it very much. It has good film forming properties and makes the product more long wearing. It's a viscous oil soluble liquid.  I achieved pretty matte finish with 10% of the above mentioned film former, 1% of boron nitride and 0.5% of silica.
    There is also another interesting product on that italian website: https://www.glamourcosmetics.it/gb/gc-syl-mat-gr-25
    I haven't tried it yet but going to get it. Sounds as a good ingredient for matte finish products.
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