chemicalmatt
Forum Replies Created
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What’s with all those hyaluronate species? Must be one helluva’ hyaluronic salesperson calling on you there. You need to be more specific in your composition. Is that “PGA” polyglutamic acid? If so it is redundant with those many HA’s. What is meant by “betaine”? If it is true betaine (trimethylglycine) that may be your problem as it may be complexing with that HA crosspolymer. Remember “less is more” as Buckminster Fuller said.
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Rapidgel EZ1 at 1.0% would do the trick and you might reduce the Olivem 300 at same time. Final viscosity would be a thin lotion more like what you are looking for.
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There would be three intersects in that Venn diagram. E.g. PEG-40 hydrogenated castor oil is an emulsifier, surfactant and solubilizer. MOST emulsifiers are also surfactants, but not so much the reverse.
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We use a Memmert HPC150 chamber and it works like a charm. How “economical” would be your call but Memmert makes many sizes to suit different folks. As for tests to conduct, standard accelerated stability conditions for pharma are 45C at 55% RH success over 90 days for prelim approval of a given formulation depending on its constitution (some formulations require lower temp/longer time.) Besides assay of your API - the most important test - you will also record pH, viscosity and any signs of discoloration or decomposition over the course of the shelf life and one year beyond. Testing labs? Too many to list, depends on your location.
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This is pushing the solubility limit for azelaic acid unless you raise the pH closer to neutral with a metal hydroxide. With a little more Polawax this should work. Xanthan gum will be dispersed into water first (NOT in the oil phase) then add AZA into water at temperature, adjust pH to 5.5 - 6.5, then proceed as planned and see what you get. I would add a little cetyl alcohol to mitigate the “soaping” from the PEG ester and improve stability at same time. Kudos to you for employing Germall as preservative.
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I think you need to more clearly define what exactly is “liquid carbomer”. There are many acrylate liquid rheology modifiers, most are 30% activity, and some are geared towards thickening surfactant systems. Others are not. If you are using one of the 30% acrylics suitable for your shampoo formula, then 1.0% w/w (0.30% solid) is far too short. Start with 3.50% and go from there. I would not adjust the pH below pH5.0 either. None of these build well below that pH and without the acid salt preservatives (as Perry remarked) you won’t need to.
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This should work just fine. I think you may be applying too much mixing there. Slow cool while slow mix and this should build, assuming your starting temp is > 75C. Finally, adding NaCl solution while at 25 - 35 C can build viscosity here too. A little bit o’ salt goes a long way and most formulators don’t know this works with cationic systems not just anionics.
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@ketchito is (again) on point there with DEL that propylene glycol/ADD anionic surfactant. That alone will boost viscosity and lessen the need for all that acrylic polymer. As for your Polyquat10 addition problem, disperse it into water directly 100%, then add the alkali needed to neutralize the acrylic copolymer to that mixture. Slowly add the acrylic as drop-in thickener and it will neutralize while addition goes on thereby not complexing with polyquat-10. Also, you might consider polyquat-7 or another cationic polymer with lower mass-charge.
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@KRISTIANA Tween 80 (Polysorbate 80) is good for 5 years, if not more, especially stored in a cool dark place. disregard what the SDS or TDS say.
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@Jorge Brenntag should be distributing all over the Iberian Peninsula. They feature BASF and SABO, two manufacturers of ceteareth-25.
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@Heath0o7 answer is negative. If you have amodimethicone pure then no need for the surfactants. Be sure to add a low temperature since amodimethicone is reactive.
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Check the SpG in a glass fritted density bottle at 60C or so using a water bath or microwave oven, wipe it dry quickly then weigh and record temp while doing so. Look up water density at that temp from the tables and you will have SpG. The SpG at 25C will not be significantly different as long as you reference water volume mass at same temp. I’ve used a 100ml Kimax graduate cylinder for this too. You get a value close enough to work with.
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I cannot recommend any of those thickeners, pal. Are you opposed to using alkanolamide builders or acrylic polymers? If acrylics are not in your plan use Poyquaternium-10 at 1.0% w/w for conditioning effect, with or without silicone, and keep it simple: alpha olefin sulfonate / disodium cocoamphoacetate / then the capryl glucoside or Ninol CAA (Stepan) dimethyl amide to build viscosity.
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The answer as @Onur states: silicone, silicone and more silicone. Nothing else beats it.
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@Lilith The “46%N” refers to the total nitrogen content in urea itself whose molecular weight is 60. The math: (2N * 14 aw = 28) then [28 / 60] * 100 = 46.6% This is 100% urea. The 46N grade is for the farmers to understand how much nitrogen they are putting into the soil.
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HCl would do a number on the aluminum part with lots of fumes to go with it. Fiberglass though? Only something very toxic would attack that. No comment.
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@Tyss Vous pouvez essayer d’utiliser silylated silica pour cette formule. En Englais: utiliser “heat and high shear mixing” to incorporate. This will be translucent, not 100% clear. D’accord?
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This has come up many times over the years. The 350cst dimethicone is the happy medium polymer chain length for hair and also skin care formula. It is not expensive either. However, I do agree with @ketchito on the amodimethicone addition here, perfect for color treated hair too. The blend with CETAC and trideceth-12 is the easiest with many clones available too.
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This does not make sense: you want water resistance but water affinity at same time? Ok, let’s leave that one aside for now. @Onur is right in that you are using the components for a barely stable o/w emulsion, co-emulsifiers all, so it is not surprising you have an unstable invert system. Onur’s helpful additions will only work in a o/w emulsion system, so be advised there too. Bottom line: you need more study on invert emulsions my friend. Also, the usually coherent and always helpful @ketchito meant “slow” addition not “low” - a typo no doubt.
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You will want to add another wax builder with divergent melt point to that, like rice bran wax, castorwax, carnauba, synthetic wax (similar to ceresin but builds better); offset by cutting back the ceresin. Plus add a small amount of lipid surfactant such as lecithin or a polyglyceryl ester such as polyglcyeryl-3 diisostearate or polyglyceryl-6 oleate. Some folks have lecithin sensitivity so be aware of that.
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The preservative efficacy questions I’ll leave to @PhilGeis and @Perry44 but I can weigh in on your thermodynamic stability issue. Most microemulsions will experience a change of state around 40 - 45C, and when that happens the test flies out the window. Same holds true with w/o and w/Si invert emulsions. These are intrinsically unstable at mildly higher temps, but quite stable at RT. I’ve had microemulsions and invert emulsions stable for >8 years, but they would have disassembled at 40 - 45C.
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@sr6866 you did not include any other formulation details so this request cannot be handled with any accuracy. What other ingredients are involved here? You need not include exact concentrations either. I’ve manufactured millions of metric tons of all the alkali hair relaxer mediums over the years, even lithium hydroxide back when it was inexpensive, so it is unlikely I’ll be surprised by anything you divulge.
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Best wishes to you @Belassi and your wife on the next chapter in life. You were always a fine knowledge contributor to this blog and you will be missed.
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@Jamiemhair Never heard of “Carbomer silk” but cationic guar and anionic carbomer do not play well together ever. This is the root cause of your problem. DEL the carbomer. Then adjust the ratio of your anionic Iselux to amphoteric betaine from 13:1 (!!) to a more reasonable 2:1. Since the free NaCl in the betaine will no longer be crashing the acrylic carbomer, you should find peace and happiness soon.
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@Fekher Ceteareth-25 without question. It hits the sweet spot of hydrophilicity, which is significant when one considers the ETO chain length distribution curves for CT-20 and CT-30 both overlap CT-25.
