chemicalmatt
Forum Replies Created
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@Shams To address your immediate question: 45C is too high for ACC testing, 38 - 43C is more relevant.(That ‘ol Arrhenius equation bedevils again!) Also, MANY formulations are unstable at 40C+ for extended periods; it doesn’t necessarily reflect RT instability in the long term though, as @Pharma expressed. Your entropic stability test (centrifuge) tells you your formula is holding up well. On another matter: what alkali did you employ to saponify stearic acid/neutralize Ultrez? That has much to do with your product’s integrity.
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@Laurentia2021have you tried a DIY version? You can just add EGDS and a little APG to your batch (skip the gylcerin - not needed) at 65 - 70C and there you are. If you must have the RT drop-in version, at 75C mix APG:EGDS:glycerin at approximate ratio 5:4:1in the lab, then tweak as desired. The glycerin merely thins the mixture to a pumpable viscosity.
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@Stanley that ZnO crash is due to the enhanced solvation of ZnO in a surfactant system crashing the carbomer/HEC rheology. TiO2 will not dissolve significantly so it doesn’t affect it same. If you want to use ZnO try a silane coated version. Also, as @Pharma and @Bill_Toge mentioned, the organic chemical sunscreens are safe excepting the ones Bill cites. Bonus for Europe and elsewhere: they are allowed to use Uvasorb HEB, the best UVA absorber in commercial distribution while us suckers in the USA are left only with avobenzone now that the benzephenones are outta’ here.
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@Stanley It may be yellow today but it will be dark brown in 2 -3 weeks. That’s Vitamin C doing what it does best: oxidizing to dehydroascorbic acid. Brown stuff all day.
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…everything @Pharma said, plus: please do not add fragrances or essential oils to pet shampoo. The creatures cannot stand it and it generally irritates their skin. Pet shampoos make the best use for “fragrance-free.”
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Clear we determine as minimum 90% transmission at 425nm in a spectrophotometer. Translucent is 65 - 90% transmission same wavelength. Below that you are semantically free to use whatever term you wish. I like “murky”. As for “straw” or “pale yellow” get thee to a Gardner Colorimeter machine my friend.
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@leftone By reducing the pH that low, you have reached the solubility limit of the free base ions both salicylic and benzoic. Unless you want to add alcohols and/or glycols to this or reduce those salts, that pH will need to stay above 4.5. That formula is begging for a glycol ether. Perhaps a Dowanol addition is in order?
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Folks, help a somewhat senior old dog chemist here: what is “fractionated coconut oil’? @Rickfon as lecithin is anionic, I would attempt to include a little anionic soap here, such as a (dare I incur the wrath of @Pharma?) phosphate ester with a higher HLB, or even Potassium Cocoate and not much of it either. On the other hand, a wee bit of PEG-10 Dimethicone will steady that w/o formula also. Honestly, I’ve never even considered using lecithin in an inverse phase emulsion before. You may be breaking new ground here.
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@domicanica what you seek is a refatting agent for this body wash product, and glyceryl oleate is a start. Without going into a long list, I’ll suggest you begin with water-soluble glyceryl esters. These will re-fat (“remoisturize”) your body’s skin without crashing foam or viscosity - a valid consideration in body washes. PEG-7 Glyceryl Cocoate is a go-to, Polyglyceryl-6 Olive Oil Esters will work if you are ethylene oxide averse. If you can handle it, polyquaterniums can offer substantial re-fatting with silicones included and are low on the irritation index too. Good luck.
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@LGrey You may have misinterpreted the INCI listing. That “PEG-40” likely preceded “Hydrogenated Castor Oil”. These are components of the same nonionic surfactant, not separate ones. PEG-40 itself would be difficult to find! (PEG-32 is a standard MW). Regarding that ringing edge pomade formulation, I found PEG-25 Castor Oil (non-hydrogenated) to work even better: nice glosser and augments the alkyl ethers in micronizing.
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Hey kids, thanks for all the kudos; and I have missed Belassi and BobZ too. I know Bob is still toiling away in the USA “Contract Manufacturing Vortex” where I’ve spent most of my career. Thanks for mentioning us all @abierose and you are most welcome. We can’t take it with us into the beyond, so Perry’s forum gives a vehicle for that knowledge share. I’ll extend my own gratefulness to @Bill_Toge, another crafty veteran like @MarkBroussard and myself. Bill has been a font of knowledge here.
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That is a factor of pH (and concentration too, of course). A 2.0% SalAc product at pH 2.5 will exfoliate almost immediately; same compound at pH 6.0 will take hours. The outcome will be same, just the contact time required much longer.
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@tecnico3vinia, that thickener is nearly exclusive for fatty alkyl ether sulfates and sulfonates. PEG-150DS does not associate well with the other surfactant classes, as you have noticed. Same holds true with NaCl: everyone thinks it thickens everything in detergent surfactant chemistry. Not happening.
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As a rule you should not add sheer stress to cationic emulsions. I am not one to question Evonik, they are wise chemists, but on this one they may be wrong on the EQ 75. Cool slowly with low sheer/slow mixing and you will come out OK.
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@Pattsi and @Pharma you both are welcome to the Matt Club, glad to have you both. Regarding that giggly effect with acrylate polymers: it may be mitigated somewhat by adding surfactants to the formulation but also limiting use of alkyl esters, fatty alcohols and other factors that associate highly with these materials.
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@seaberry I may be stating the obvious here: DEL the SCI altogether. The oil component (identity?) is doing the heavy lifting in makeup removal, your surfactants are mainly employed to remove both oil solvent and makeup. Why not select another nonionic surfactant to solvate/remove the collective crud or just q.s. with the glyceryl ester?
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Matt (another Matt here? uh oh!) - always disperse and hydrate the polymer into water at RT first before adding any other component.
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Increase the CAPB, but decrease the AOS at same time. Increasing the GCC by 0.50% should help foam and viscosity. You may increase the glucoside too but not too much.
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That will be formula dependent @Henry. If no cationics are present,then add your anionics (e.g. SLES, Na sarcosinates, etc.) first, then nonionics, amphoterics, builders. When using multiple anionics, add the least soluble one first (i.e. sarcosinates).
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@Henry Reduce all that fatty alcohol as @singhc10 alluded. You are experience the “chalky” effect of too much of that, perhaps not “tacky”. What is “fruit oil”? that might also be a culprit. Otherwise tackiness will be a mystery: with all that dimethicone and quat in there, this should be gliding like Clyde. BTW, what’s the matter with a pH 3.5? Nothing to worry about there my friend.
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Affirmative. It releases ammonia even at RT if the pH is left higher than 8.
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@Henry that dictum applies whenever you are building a conditioning shampoo with cationic materials or when employing an acrylate copolymer thickener. Otherwise you can add in any order you like, there is not much difference in zeta potential so much as there is in activity levels.
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What @Bill_Toge said. Agreed. You can’t believe everything the “listings” claim. The “polyols” useful for this are the PPG/PEG block copolymers, not the smaller molecule humectants. Sticky stuff those. BTW @David08848, for a nice, cheap foaming enhancement in your shaving cream try good old sugar (sucrose or xylose). Offset the stickiness with a PPG/PEG polyol or just butylene glycol and enjoy.
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@Abdullah, this system is under-built. Increase the CAPB by a factor of 3, likewise the glucoside. Glyceryl Caprylate/Caprate is a good builder choice there -perhaps increase that too? I’ve never heard of 100% active AOS “powder”, and what is “EO” ? You also want to DEL the guar gum. Why use when you have already cationic guar?
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Palmitic acid is a good builder in structured body wash systems - the kind with spherulite oil loads embedded. It’s also a critical element in traditional shave creams with tromethamine. Other than that, stearic has better performance in most applications and is a few shekels per kg less expensive to boot, so that may be why you don’t see it as often.