[Bill_Toge]

@ngarayeva001 sounds like it was formaldehyde-based - a year or two ago, Trading Standards impounded a load of hair straightening products imported from Brazil because they released large amounts of formaldehyde in use

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forgot to mention, you also need to use deionised water to make the product - preferably 5 µS/cm or less, as traces of metal salts in water can very easily decompose peroxide

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what’s your budget?

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depends how small the average particle size is

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try heating it up and/or applying shear to it; from experience, I know CI 47000 in particular is very, very slow to dissolve at room temperature

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in all honesty I normally use conventional emulsifiers combined with a hydrocolloid in the water phase to control the texture, and I only use polymeric emulsifiers for the most difficult/temperamental formulas

but if you want a rheology modifier than can stabilise emulsions, cetyl hydroxyethylcellulose is an excellent all-rounder

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@ngarayeva001 what did it smell of?

if it smelt of rotten eggs, it was most likely thioglycolate; if it had a very harsh, sterile smell, it was more likely to be formaldehyde-based

the London salons are likely to be using products containing functionalised keratin derivatives - Croda sell many raw materials for this purpose

[Bill_Toge]

your pH needs to be below 4, and you need a chelator plus a stabiliser e.g. sodium stannate, or etidronic acid

[Bill_Toge]

ngarayeva001 said:

I wonder if aspirin even works for this purpose. I heard that many times, but as far as I understand aspirin is acetyl-salicylic acid which is a different molecule.

it could potentially work if the O-acetyl group were to be hydrolysed by esterase enzymes in the skin, but the rate of action would be much slower than with salicylic acid (see also: retinol vs. retinyl palmitate)

@Doreen also salicylic acid in bulk is nasty stuff; there’s a good reason it’s limited to 2% in leave-on products and 3% in rinse-off products

[Bill_Toge]

@ngarayeva001 for W/O products you definitely need a homogeniser with a very fine screen, or an extremely high-speed mixer (10,000+ rpm) like an Ultra Turrax

also, it helps to form the emulsion at as low a temperature as practically possible, so any solubility variations during cooldown are kept to a minimum

speaking from experience, the easiest way to clean homogenisers once they’ve been in products like this is to run them in a mixture of very hot water and alkaline detergent; this will shift a lot of the product and reduce the amount of elbow work required to get the rest of it off

[Bill_Toge]

Pharma said:

Why BHT? Apart from traces of Tween 20, the formula is fairly “natural” and and skin-friendly whereas BHT is a potential allergen and one of the “bad guys” of these days. Why not add tocopherol (tocopherol acetate is not an antioxidant) and ascorbyl palmitate (ascorbyl phosphate is not an antioxidant as well)? This synergistic combination is more efficient than BHT regarding anti-rancidity. Or use rosemary extract.

A natural alternative to EDTA would be phytic acid and, less efficient, citric acid.

that’s as maybe, but BHT has much less potential for contact dermatitis than retinol itself; it’s also effective at very low levels (ca. 0.1%) and doesn’t make the product smell or discolour

[Bill_Toge]

Pharma said:

I admit, I kinda always think of TEA as triethylamine because that’s what I used in the lab and it shares the same abbreviation.

trust me, it’s nowhere near as foul-smelling as triethylamine

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how fine is the screen on your homogeniser, and what speed are you running it at?

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simflyer905 said:

Thanks Bill, I appreciate your input.  Would it be possible to substitute a broad spectrum preservative like Germall plus (or something that can tolerate higher temps) and effectively eliminate ingredients 7-10 ? 

absolutely: any heat-stable preservative will do the job just as well, if not better

You mentioned this will be most challenging - what aspects?   Finding the right consistency, temps, stirring, cook time, etc? 

the aspects of successfully deriving a formula which can successfully reproduce the product, finding out the mechanics of the formula, how the formula fits together, the best temperature to fill the product at, etc. - this all takes time and practise to master, and this is quite an unusual/esoteric product type compared to most cosmetics and toiletries

Lastly, what am I attempting to make here?  Oil in Water emulsion or Water in oil emulsion?   You mentioned this is water based.

to be honest, it’s neither; the best description I can come up with is that it’s a highly concentrated dispersion of a high molecular weight hydrophilic surfactant (ceteareth-30/25/etc.) in water; the wax-like consistency is due to the surfactant’s concentration being so high that the molecules form strong bonds with each other as well as with the water, and when cooled below a certain temperature, the mixture of water and surfactant coagulates and takes the form of a soft solid

as I said: it’s complicated!

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the legal limit is in place to limit the exposure to residual diethanolamine, which is produced during the manufacturing process and is typically present as an impurity, to the maximum dose known to be safe

many of the limits in Annex III are based on the maximum dose which is known with absolute certainty to be safe - the practical limit could potentially be higher, but there is no positive and convincing proof

[Bill_Toge]

7 and 8 are also part of Kathon CG (or one of its numerous knock-offs), as they are the stabilisers for the preservative; incidentally, that preservative is wholly unsuitable for this product as it’s temperature-sensitive and the product needs to be filled hot, which means the preservative will slowly be destroyed during the filling process

for mineral oil, a pharmaceutical grade is the cleanest and least smelly

also, if you have no practical experience, I must warn you that
water-based hot-fill styling products like this are one of the most
complicated product types to formulate - I’d suggest you start with
something simple like a skin cream and get a feel for the concrete before tackling
something like this

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from my experience, the pigments in these coloured micas are deposited onto the surface of the mica in thin layers, rather than being mixed with them in the conventional sense; I don’t honestly know how this affects the biochemistry, but major manufacturers (Merck, BASF, Eckart etc.) routinely highlight regulatory restrictions for these pigments in their literature just to be on the safe side

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no, but you do need a toxicologist to sign off the safety assessment - many independent consultants and consultant companies offer this service

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what temperature was the batch when you added Optiphen?

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no worries! if truth be told it’s no effort at all as far as I’m concerned; I’ve worked at the sharp end of the industry for 10 years now and accumulated most of my practical and theoretical knowledge by keeping my eyes and ears open, and I just offer advice etc. out of a desire to be helpful

the reactivity of amines towards the nitrosonium ion can be summarised in this reaction diagram, which runs anti-clockwise from top left to top right:

with a primary amine (one carbon substituent, like the one in the diagram) the reaction goes to completion and forms a highly reactive diazonium salt

with a secondary amine (two carbon substituents) the reaction terminates at nitrosamine stage because there are no H atoms available to form the diazohydroxide

with tertiary amines (three carbon substituents) the reaction doesn’t occur, because the first intermediate is inherently unstable and there are no H atoms available to allow nitrosamine formation, so it decomposes back to the starting materials

with quaternary amines (four carbon substituents) the reaction doesn’t occur at all because there are no free coordination sites on the N

[Bill_Toge]

you need a secondary amine group and a nitrosating agent to generate nitrosamines; TEA is a tertiary amine, not a secondary one, so it is not physically possible for it to form nitrosamines

also, urea is not a nitrosating agent and cannot easily be turned into one

carbomer are a set of polymers of acrylic acid, which have variable chain lengths, complex structures, molecular weights of multiple million Daltons, and no general empirical formula; they are not the same thing as acrylic acid, so calculations made using acrylic acid are meaningless

as it happens, Lubrizol have made a handy chart showing how much base is required to neutralise their polymers (Figure 4 in this document); this is a good guide for carbomers in general

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is the cap wadded, and if so, is the wad water-absorbent and breathable?

non-absorbent wads can cause terrible problems with condensation, even in temperate climates

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depends on the grade of paraffin/microcrystalline wax - depending on the linear/branched ratio of its constituent hydrocarbons it can be malleable or brittle

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you need more liquid in your oil phase - the flaking occurs because your oil phase is solid and can’t spread easily

agree with @natzam44, polysorbate 60 and 80 are terrible for knackering preservatives; I’d suggest using a different emulsifier

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also, I am all for making web pages legible and find tiny text irritatingly hard to read, but this website goes to the other extreme - the pictures and font size are ENORMOUS on my screen