ketchito
Forum Replies Created
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@Dreamer77 I’m sorry, but you’re being disrespectul with some of the best formulators in the industry which are here in this group, and that tried to help you. The reason why you were asked for the list of ingredients (which will be public anyway if you sell your product), is to spot potential interactions that might cause the issue. No need to post percentages…without that info it’s impossible to give you advice, but it’s your choice.
I’m glad you managed to solve the issue (it’s better though to test the stability over time). About reliable source of information, patents are only informative (they are not peer reviewed evidence), being clinical studies (with robust methodologies and published in peer reviewed journals) the most reliable source of information for efficacy, which are scarce due to the high costs and the standards for being approved. And most of the high cost actives fail to pass this test (that’s one of the reasons suppliers almost never publish their results in peer reviewed journals).
I hope you succeed in your project, and keep in mind that we are here only to help, but we need information to do that.
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@Abdullah At such low level of anionic surfactants, it’s for sure that either Cationic guar gum or/and PQ-10 will form an insoluble coacervate. You need to have an excess of anionic surfactant compared to your cationic polymers to dissolve the coacervate.
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@crillz Higher pH will help for sure. I would also try things:
1) remove the styrene acrylates (if that works, replace it by a glycol distearate dispersion)
2) increase SLES (this will help solubilize any hard phase that tries to separate, close to 14-16%)
3) replace decyl glucoside by coco-glucoside (decyl glucoside might be reducing your viscosity, and that’s why you need things to ncrease)
4) decrease PQ-10 (not more than 0.2-0.25%)
5) decrease your DEA (no more than 2-2.5%)
6) decrease CAPB (no more than 4%) -
@Abdullah My apologies, I missed the point of your question. the skin barrier is our body’s natural defense that protects the skin from foreign agents (eg., pathogens, allergens, particles, etc.). To put it simply, it’s a very tight arrangemet of fats and humectants. Because of this tight arrangement of mainly fats, water and ions transport is only possible through specific channels (aquaporines).
The humectants (wether occlussives, emollients, hydrating agents) work to recover/improve this natural barrier.
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@PassionFruit95 No worries, I know how frustrating that is. The lamellar gel is just the way surfactants arrange in a water solution at certain concentration. Imagine a bus, if a couple of people travel in it, they can stretch their legs and wander around freely, but the more people come inside, the less mobility they’ll have and they might to find ways to organize themselves so more people can get inside. That also explains the increase in viscosity in these systems. Well, the problem is when certain types of surfactants are all together, like a system with SLES-CAPB-DEA. This system is very common, but CAPB can be very picky (especially at high doses). So, if a PQ wants to join the party, CAPB might not be so pleased since PQ likes to stand with the eldows bent. This is even worse in the presence of NaCl, which can make your SLES-CAPB-DEA-PQ very unstable. The way this systems separates is from the bottom (like the courtains in a nice theater), you’ll see how it’ll slowly go up, leaving water phase at the bottom; gradually, the water phase will increase while the lamellar system that is separating will decrease, till a thick phase at the top remains.
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@Abdullah I wouldn’t directly compare them all, since they work in different and synergistic ways, as @vitalys mentioned. For instance, Glycerin doesn’t prevent water loss (since it’s a small molecule), but rather penetrates the skin; it works both by being a source of water and also, to aid in the recovery of the skin barrier. Dimethicone and Petrolatum both reduce TEWL (dimethicone less than petrolatum, since it’s less occlusive), and butters deliver emollients that help recover the intracellular matrix at some extent (whici inderectly reduces water loss as well). That’s why in humecting creams, you have a combination of them rather than just one.
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@Abdullah I always rely more on independent data rather than supplier’s. Keep in mind that the main intention of suppliers is to sell. Also, PQ’s, gums, silicones, they are all different types of molecules and they give different results…and those results also depend on your system, wether you have the tendendy to form a coacervate in your formula or not, wether you have a cationic surfactant and this has a low molecular or high molecular weight, etc. Actually, many of those things are explained in that book, and trust me, Dr. Goddard was one of the finest scientists that ever walked the cosmetic industry. There is also another book co-edited by Perry: “Conditioning agents for hai and skin.”
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@PassionFruit95 Yes, and if your final viscosity is too high, that means you need to reduce some of the viscosifying agents (I’d go for reducing Carbopol a bit -not less than 0.35%, to help suspend silicones-, Palm Kernelamide DEA -2.0-2.5% would be a good level-, and PQ-10 -you might not need more than 0.3%, since that PQ actually builds up more than others on hair-).
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@KarolinaPL If you’re using a 10% solution of PQ-7, you could try increasing it to 2-3% (or replacing it by Guar hydroxypropyltrimonium chloride at 0.2-0.3%). You could also try replacing your silicone system by either Dimethicone (1000 cSt would be OK) or Dimethiconol (for instance, DC 1784 which is 50% Dimethiconol) or a mixture of both, at a total silicone content of 2-3%.
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@Abdullah My apologies, I should have added the edition from the book (the one from 1999). I’m pasting a couple of screenshots where you can find the info I mentioned.
My comment about the water soluble cationic polymer (WSCP) vs amodimethicone in a shampoo, was just to show that the WSCP in the presence of some anionic surfactants (like SLES) will form a coacervate (neutral) during dilution rather than being in a free cationic state. This complex will force the system to invest energy to keep it in the system (it’s like holding a baby that suddenly gained 40kg). That’s why coacervates readily stick to any surface which is good in terms of short term condicioning, but not only they don’t deposit in specific sites, they are hard to remove (at least, not completely). Amodimethicones on the other hand, they have both electrostatic (charge) and dispersion (size) forces to deposit on a surface. Dimethicones can actually deposit along with the coacervate (that’s why PQ’s and Guar gums are said to increade silicone deposition), but that’s not the case with amodimethicones. In the case of emulsions, you have WSCP in a free cationic state, and the competition for binding sites with amodimethicones is more straightforward (but interestingly, cationic surfactants do increase deposition of amodimethicones in emulsion systems).
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@PassionFruit95 I had a similar issue back in the day. On one hand, you could have creaming due to your silicone, and that’s solved by increasing viscosity, especially increasing your suspending agent (in your case, your Carbopol Ultrez 20). The addition of Cutina AGS might help with the increase in viscosity (but not on the suspending part). By the way, what are you neutralizing your Carbopol with? Keep in mind that most carbopols come in an acid form, and needs to be neutralized to develops all its viscosity/stabilizing features.
But, consider also that your system SLES-CAPB-PQ-DEA, which is very sensitive to low pH and electrolytes. What’s your final pH? is there any chance you’re adding sodium chloride or related inorganic salts?
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@Abdullah You can find the support to my statement in the page 301 of the book “Principles of Polymer Science and Technology in Cosmetics and Personal Care” (chapter Silicones in cosmetics). It’s only fair to think that if the driving force for the deposition of a molecule is of electrostatic nature, molecules of the opposite charge to the substrate will compete for these sites (eg., cationic polymers, cationic silicones, cationic surfactants, cationic aminoacids/peptides, cationic inorganic ions, etc.). Since small molecules difuse faster, they can bind easier to anionic binding sites (that’s why sodium ions and cationic surfactants bind preferentially than cationic polymers o silicones). Now, when you compare a cationic (water soluble) polymer vs amodimethicone, it depends on your system; if you have a shampoo and a coacervate is likely to be formed, then the means of deposition of the cationic polymer will be through reduction of free energy in your system. If on the other hand you have a conditioner in which a cationic polymer and amodimethicone are present, then both molecules are likely to compete rather than help each other deposit (consider that keeping a hydrophilic cationic polymer suspended in your system requires less energy than keeping a cationic silicone, and also, there’s a barrier surrounding cationic polymers (solvated by water molecules). With that, I mean that for big molecules, there’s more than one driving force for deposition.
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@PassionFruit95 There are few things to adjust in your formula (like excessive menthol -irritant to some people at high levels-, fragrance and glycerin), but if we want to focus on the issue, I’d think it’s your MEM-1784 (5.5% is also a bit too high) the issue. How much is your viscosity? This silicone tends to cream on top of the product in stability testing, especially when the viscosity is not too high. Now, if the layer on top of the product is not thin, but rather thick, then you might have some instability with your lamellar system (the one formed by your surfactants/polymers).
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Abdullah said:@ketchito 30 minutes for what batch size?
Let’s say for a 100kg, but this also depends on your mixing speed and the ratio of your mixer diameter/container diameter, so the 20-30 min are referential (the main idea is to give the system enough energy to overcome crystalization while increasing interactions for later micellar arrangement).
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@Abdullah Take into account that it’s supplier’s data, so the results will always be more dramatic in favor of their ingredients. That said, the type of silicone matters a lot, being neutral silicones (like dimethicone) deposited better when used with a cationic polymer. Amodimethicones, not only could compete with cationic polymers for binding sites on hair, they tend not to build-up due to electrostatic repulsion once the first layer has deposited.
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@ajw000 I usually heat to 75-80°C and keep the mixture at high shear for about 20-30 min (enough mechanical energy for difussion, colisions, etc.). Then I reduce mixing gradually while it cools (to let the emulsion system arranges), and finally remove mixing at around 45-40°C (from this, entrophy of the system will reach and equilibrium). Maybe you could try this to see if it improves.
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@Abdullah I’ve seen Sulfonates (like AOS) as very common anionics in low pH products.
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@poonpf I don’t think you’ll have skin irritation from IPL, as long as you don’t use too much of that ingredient. But if you do and your concern is about skin irritation, I’d go for the blend, as long as it means you’re replacing part of the IPL with IPP.
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@Iwana You might want to chek this thread about a similar issue (https://chemistscorner.com/cosmeticsciencetalk/discussion/2061/discoloration-during-stability-test).
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@Abdullah Keep in mind that guar gum, unlike cationic guar gum, is not positively charged, so it doesn’t have that driving force for deposition, only the molecular wight.
Build-up from coacervates happen due to both overdeposition of the coacervate, and how difficult it is to remove it completely from hair, even for stronger surfactants.
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@poonpf Indeed. An alternative would be to search for a palmitate instead of a laurate, although the after feel might vary a bit.
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@Abdullah Gums can deposit, merely due to their size (molecular weight), and through dispersion forces. Also, its water solubility plays a role, the more water soluble (or dispersible) they are, the less chances they’ll deposit.
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@Abdullah SLES due to the presence of an ether group, might be the more sensitive of that group. I remember some degree of hydrolisis might occur below a pH of 4 (at higher pH, some hydrolisis can also occur, it’s so little and slow that it becomes irrelevant). That’s why acid cleansers don’t use SLES.
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@Zara Proteins actually have very interesting interfacial activity in surfactant systems. I remember attending a lecture from Dr. Lochhead talking about more natural coacervates formed by the interaction of proteins and anionic surfactants. There are very few papers about this matter, here’s one of them (https://www.researchgate.net/publication/284469435_Complex_coacervates_of_whey_proteins_and_anionic_polysaccharides_and_their_use_for_encapsulation).
I remember also in some tests we did back in the day, foam in some surfactant systems was increased in the presence of whey protein. Also, if I remember correctly, there are interactions between protein isolates and some gums, which result in increased viscosity of some systems.
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@Yulin If you just want to identify the presence of Polysorbate-20 (and it’s the sole material, and not a final product -cream, conditioner,etc.-), then you could use a FTIR, UV or any other spectroscopic technique you have available to identify it.