Bill_Toge
Forum Replies Created
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xanthan gum and cellulose gum are both anionic, so they’re inherently incompatible with quats: the quickest and easiest solution would be to use a different thickener
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speaking from experience, they are not ‘inactivated’ by cellulose derivatives; rather, their efficacy is reduced
i.e. the preservatives in question will still work, but you’ll need to use them at a higher level
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try it and see
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you also need a high-shear mixer of some kind to ensure the zinc oxide is fully dispersed
also, what grade of zinc oxide are you using?
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and in any case, sodium ions from salt in surfactant-based products are bound to the surfactants, so they don’t behave like a solution of salt
there’s an awful lot of people out there who missed that memo, though
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what material(s) does Sebum Control consist of?
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heat makes peroxide work more quickly: it doesn’t change the actual amount of peroxide
I strongly suspect the variation seen in practise depends on the structure, amount and condition of the hair of each individual, and is unlikely to have a simple linear rate/temperature correlation like this, simply because the reaction between peroxide and melanin has a very complex mechanism
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if it doesn’t happen in a closed container, the product is most likely losing water and drying out in the air
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liquid emulsions (e.g. cosmetic products) are formed when both the oil and water phase are liquid: if there are solid materials in the oil phase, they need to be heated to a high enough temperature to melt
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whoever has supplied them with the formula has either a) made a complete hash of compiling the list, or b) has tried to keep the exact formula secret, deliberately missed out key ingredients, and gambled on the fact unless they’re cosmetic chemists, most people wouldn’t notice that the list is incomplete
it’s not legal at all, but unfortunately it’s very common practise
also, I noticed there’s apparently no wax, or fixative resin in it either
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they are still permitted in Europe, but they’re restricted to rinse-off products only - this is the status they had before the limit for MIT was increased, and the scope of usage was widened, in 2005
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in my last job, anything with salicylic acid as an active ingredient (antibacterial handwash, and an anti-dandruff shampoo) had a pH spec of 3.5 - 4.0; this was low enough to allow the salicylic acid to work effectively, but not low enough for the product to be irritating
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in this case separate solutions would be the better option: even if you dissolve the sodium benzoate first, it’ll precipitate and eventually crystallise out
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if it’s a real problem, try using a different emulsifier: prevention is better than cure
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try ethyl cellulose
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the expiry date is simply the latest date the supplier can guarantee it’s fit for use and is liable for it; it’s not necessarily the point where it becomes unfit for use, as some materials last many times longer than their indicated shelf life
after the expiry date you are basically using it at your own risk, and the supplier can’t be held responsible for any undesirable effects
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the shelf life is simply the period over which the supplier can guarantee the material will remain fit for use; it may well remain fit for use beyond that time in practise, but the supplier can take no responsibility for it unless it’s re-tested and re-certified with a new expiry date
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the rate of hydrolysis also depends on the amount of acid and its strength
at pH 2, you’ll either have an awful lot of acid or a very strong acid present, so it’s not representative of conditions found in a cream or a lotion
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imagine the reaction if they were to find out the air we breathe mostly consists of E941 and E948
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and as for acid dyeing at room temperature: why not try it and see?
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polysorbate 60 and 80 reduce the efficacy of preservatives at high levels, but this is not generally true of non-ionic surfactants
also, what’s your source for preservatives and plastics interacting?
in my experience the only things likely to attack plastic are strong oxidising or reducing agents (peroxide, thioglycolate salts), or organic solvents
and personally, I’d avoid potassium sorbate, as it’s terrible for turning liquid products yellow/brown over time
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also, I’d suggest you look up the process of acid dyeing, and how it works
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anecdote time, related to @MarkBroussard‘s list above: I once got a sample of vanillyl butyl ether, and put a drop on the back of my hand to test it out; five minutes later, my hand felt like it was on fire, and stayed like that for several hours
needless to say, were I formulating a product for use on the genitals, it would not contain vanillyl butyl ether
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you’re better off using dimethyl ether
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if you want to give your product more lubricity and a smoother skin feel, in my view you’d be better off including oleic acid, or an oil which is high in oleic acid