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Jaguar HP 105 (HP Guar) Viscostiy/ Thermal Stability
I have been experimenting with Jaguar HP 105 (Hydroxypropyl guar) for some various leave-on cosmetics and I noticed viscosity of my samples decreasing over time. So I made a 1.5% solution of Jaguar HP 105 where I adjusted the pH with Citric from ~10 to ~7 and used 0.7% euxyl pe 9010 (phenoxyethanol, ethylhexylglycerin) to preserve, then placed the sample in a 45C oven for 2 weeks. The viscosity across almost all shear rates dropped but it was especially noticeable at low rates (almost 50% reduction) and visually the sample looks thinner. I haven’t worked with HP guar much but is it normal to see a decrease that quickly, or is that an indicator of a bad batch/improper processing?
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7 Replies
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@evchem2 hydroxypropyl guar is really great to work with, more formulators should, and it is good you mentioned a visual decrease in viscosity. The one thing I can share is many guars are not long-term stable with glycols including glycerin. I recall needing to use “glycol compatible” HP guar in the past. There may be other materials in your formulations that break the saccharide chain down to size, the cause of viscosity drop. E.g. Guars are stable with electrolytes until the point they are not. Here’s a hack if you can stand it: add a little sodium borate solution and watch it cross-link into a gummy - just like that.
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@chemicalmatt thank you! That’s wild, I didn’t include that I had 3% glycerin in the system (the only other component) because I assumed it would be negligible…I recall a saying about assumptions that seems relevant. Any idea the reasoning behind the incompatibility?
Thanks for the tip about the borate, not sure how client will feel about it but good to have in the toolbox
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What is great about it? Emulsion stabilizing, viscosity increase, foam increase, skin feel or something else because it is not an inexpensive ingredient.
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hydroxypropyl guar is it formality of hydroxypropyl methylcellulose (hpmc)?
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Guar hydroxypropyltrimonium chloride is a different molecule than Hydroxypropylmethyl cellulose, and are used for different purposes (athough the first one gives some viscosity as well, especially in low pH surfactant-based formulas).
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Guar hydroxypropyltrimonium chloride is For low surfactant-based formulas, you mean that? Thank for information
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Sorry for not being so clear. Guar HPTC is a conditioning agent with some thickening propertirs…but mostly conditioning. That’s why it’s commonly present in shampoos. Now, for a shampoo that has Guar HPTC, you could get a bit of extra thickening, if you lower the pH.
Hydroxypropylmethyl cellulose is not a conditioning agent, but a very eficiente thickening agent.
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