Hand Sanitizer Gel not forming gel with hydroxypropyl guar

Formulating

Hand Sanitizer Gel not forming gel with hydroxypropyl guar

Posted by mindycheng on May 23, 2018 at 12:29 am

Hello,
I’m trying to make a hand sanitizer gel using the following formula, and the hydroxypropyl guar is not forming a gel and I’m not sure why.

35% water
62% ethyl alcohol
2% hydroxyproply guar
citric acid (to reach 7pH)
1% essential oils

I mix the water and alcohol, then add the guar. I then add a tiny amount of citric acid to reach a pH of 7. I mix for 10-20 minutes but no gel is forming. Just a cloudy mixture.

I got the formula from here but modified it a bit:

https://www.personalcaremagazine.com/formulation-details/2372/lamcos-102-hand-sanitizer?companyid=3423

I appreciate any tips or insights. Thanks!

Microformulation replied 6 years, 4 months ago 10 Members · 18 Replies
18 Replies

belassi

Member
May 23, 2018 at 2:14 am

You left out the Alpicare. Which is to omit several important ingredients that solubilise and emulsify.
Chemist77

Member
May 23, 2018 at 3:32 am

In addition to what @Belassi said, I would do the neutralization just in water.
DRBOB@VERDIENT.BIZ

Member
May 23, 2018 at 3:41 am

You forgot Part B and are better off using a Carbopol with Ph at 6.5:HEC will gel also but make sure it is completely hydrated in water before adding alcohol.
mindycheng

Member
May 23, 2018 at 5:07 am

Thanks everyone. I was wondering how The Honest Company makes their hand sanitizer which doesn’t seem to have any solubilizers or emulsifiers, at least from what I can tell… I’m new to formulating, FYI. See pic.
Duncan

Member
May 23, 2018 at 7:27 am

Check the grade of Guar you are using. Some are optimised for alcohol use, some are better for using in things like shampoos and conditioners.
I’m more familiar with Jaguar grades from Rhodia, however, there will be local equivalents out there
Duncan

Member
May 23, 2018 at 7:31 am

Noticed that you are using Esaflor - homogenise that into the water phase, add the alcohol slowly with stirring.
I’ve not had to add citric / alkali to get it to gel
It isn’t 100% crystal clear in the applications I’ve used it in
OldPerry

Member
May 23, 2018 at 12:24 pm

The Honest company has been demonstrated to be dishonest so I wouldn’t put a lot of faith in the accuracy of their LOI. But if we assume in this case they are being honest, there are no oils in the formula that would require emulsification. All their ingredients are likely water soluble. In your formula, the essential oils require some type of emulsification.
em88

Member
May 24, 2018 at 7:16 am

I’m confused with citric acid used to adjust the pH to 7. Also why pH 7?
You should add glycerin, it should increase the viscosity by little.
Nitrocellulose will create gels with alcohol.
You may try HEC but with that much alcohol, it may precipitate.
belassi

Member
May 24, 2018 at 2:30 pm

Nitrocellulose will create gels with alcohol.
Sounds like a hot item! Nitrocellulose is an explosive.
em88

Member
May 24, 2018 at 3:16 pm

You are confusing nitroglycerin with nitrocellulose 🙂
belassi

Member
May 24, 2018 at 4:19 pm

Not at all. Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, and flash string) is a highly flammable compound formed by nitrating cellulose through exposure to nitric acid or another powerful nitrating agent. - Wikipedia
em88

Member
May 24, 2018 at 7:28 pm

It is flammable but not an explosive like nitroglycerin is.
The exact type of nitrocellulose I’m talking about is pyroxylin.
Bill_Toge

Member
May 24, 2018 at 11:11 pm

in the dry form industrial nitrocellulose is EXTREMELY flammable and very temperamental, by far the most dangerous material used in cosmetics and toiletries

flammable solvents are well-behaved if stored and handled correctly, but nitrocellulose catches fire at the slightest provocation, and because it’s oxygen-rich, the fire is self-sustaining, meaning it is very difficult to put out
belassi

Member
May 25, 2018 at 1:42 am

Pyroxylin definition: a yellow substance obtained by nitrating cellulose with a mixture of nitric and sulphuric acids (Collins dictionary)
- I take it that you’re not too bothered with all that “naturals” rubbish. Good man! You tell ’em!
em88

Member
May 25, 2018 at 7:14 am

@Bill_Toge, I agree with you. It is very flammable, and needs a lot of caution. But is the best one (from what I know) to for clear alcohol gels.
Boots uses pyroxylin in they Bazuka gel line products. I’ve seen other manufacturers as well.

@Belassi, there is a huge list of the same rubbish added in shampoos, what about that?

Calcium acetate should form gel in ethanol as well
Smuts

Member
July 30, 2018 at 11:08 am

@em88, as I understand it calcium acetate will basically form a white gel, correct? Is there another substance you would recommend to form a nice clear gel for a hand sanitizer that one wouldn’t have to be worried would spontaneously combust, instead of pyroxylin? I used an acrylate copolymer, but it doesn’t seem to give us the thickness we want, just a very runny almost-gel.
em88

Member
July 30, 2018 at 11:38 am

I came across a new product, I’ll probably get a sample soon, it is optasense g82. Inci, acrylates/c10-c30alkyl acrylate crosspolymer. They say that it can form gels even with higher concentrations of ethanol if it neutralized with a suitable base. For example if you use TEA, a gel is formed with up to 60% alcohol.
If you want I can give you the presentation.
Microformulation

Member
July 30, 2018 at 3:49 pm

You can achieve the same result with Carbopol Ultrez 20. https://drive.google.com/file/d/1z_yRupdCA8cWpMplKpLzYqpW5DUFApKx/view?usp=sharing