SkinNP
Forum Replies Created
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Thank you for the rec, chemicalmatt
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I could genuinely use an education here. Could someone help me understand how a chelating agent boosts preservative efficacy? Thanks!
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Very appreciative! Thanks
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Many thanks to you both
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Just an update for anyone having difficulty replacing betaine with sultaine:
In my further work, higher pH (7.
did not improve stability of the sultaine formula. HEC, HPMC, and carbomer were similar failures. Crothix Liquid looked very nice until showing subtle precipitate after about 1 month in 50C. I found that NaCl level was 5% in my CAPB, and close to 7% in my CBS… so I decreased the amount of CBS as compared to the CAPB in the original formula. This seems to help some. Reducing the amount of EO helped much more. Still working on it. -
Many thanks to ngarayeva001 for the professional and helpful posts. I was considering Crothix…
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Update: I duplicated the failure, and appears to me that xanthan gum is settling to the bottom. I again made the stable cleanser formula with exactly the same process and % solids, except that I replaced cocamidopropyl betaine with cocamidopropyl hydroxysultaine. I adjusted pH to 5.4 and let the solution sit overnight at RT before the final step of adjusting viscosity with xanthan gum (pre-wetted with glycerin). Looked like a gorgeous solution the next morning, until I added the xanthan gum. Despite what I consider adequate mixing, I have an opaque layer at the bottom of the vessel that appeared within an hour or two — it’s about 15% the total height of the mixture. Wondering if anyone has any thoughts how to correct this, or an alternative thickener for sultaine + coco glucoside that would have an EWG hazard score no higher than 2?
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Not sure what you are making, but I’ll give what I have learned so far and let others chime in to correct the record if they see fit. Stirring doesn’t mean you have produced a homogeneous mixture, but if you have homogenized then you likely did so by stirring (maybe agitation is possible in other contexts as well). So, when they say homogenize, I think they’re saying disperse ingredients evenly (presumably by stirring). No skin off my back if someone wants to differ with me on this.
Mixing equipment is really important. Bad equipment will frustrate you, and make your results hard to duplicate. Make sure the shaft is true, the range of speeds appropriate, and the propeller shape and size appropriate for what you are aiming to achieve. I try to get the propeller to about 2/3 the depth of the material. The mixing vessel should be at least 3 times the diameter of the propeller, have straight sides, flat bottom, and not react with your ingredients. Mix at a speed that doesn’t introduce a lot of air into the material, or cause foaming. In my experience, you need at least 20 minutes at a speed sufficient to produce a nice vortex (but not much faster).
For what it’s worth. Good luck.
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My name is Shannon Johnson. I’m a nurse practitioner on Boston’s North Shore. Since 2017 I’ve been laying groundwork to launch my own skin care products for specific clinical conditions. I’m lucky enough to have a husband who is a chemical engineer and runs a manufacturing company, and who encouraged me to start by getting some education in cosmetic formulating (he found and steered me to the Practical Cosmetic Formulating courses). I’d like to thank the many people who share their expertise and insights on this forum in a professional and courteous way, and hope I can return the favor. Looking forward to Suppliers’ Day 2019!
