Bill_Toge
Forum Replies Created
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@Perry god almighty! on this side of the Atlantic, you’d have to work in the sales and marketing department to earn that sort of money
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try adding some stearic acid
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agreed: ascorbic acid is notorious for browning in water-based formulations
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most likely your broccoli seed oil; it’s likely to contain some sulphoraphane, an organic sulphoxide which boils at about 130 °C and may well have a significant vapour pressure below that
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for O/W, it doesn’t matter which way the phases are added to each other - the laws of thermodynamics do the majority of the work, and any preference for one way over another would be purely practical, dictated by a) the relative ratios of the two phases, b) what kind of equipment you’re using to form the emulsion
what else have you got in the formula?
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actually, now I think about it, I realise TEA is also a lot less nucleophilic than hydroxides, so you’ll be lucky to get any hydrolysis at all
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you’ll need a Cosmetic Product Safety Report, which is a paper exercise carried out by an accredited toxicologist; a reputable and ethical toxicologist will want to see the MSDS and specs for any of the materials you use, and IFRA certificates/allergen declarations for any essential oils, before they can sign it off as safe
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try adding it to the oil phase; I wouldn’t recommend using DMSO in anything topical
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I should think it’s possible, but it’ll be a hell of a lot slower as TEA is a significantly weaker base
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are you heating the batch, and if so, to what temperature?
also, how are you mixing the two phases together?
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a rotor/stator mixer will do the job much better, as it forces the liquid through a small, well-defined gap, allowing the emulsion to be formed more easily; and at 2000 rpm, an overhead mixer will fill your batch with air
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in order to form a W/O emulsion, the water phase must be dispersed into the oil; this is complicated by the fact that water droplets have a much stronger tendency to aggregate than oil droplets do
the purpose of magnesium sulphate is to increase the ionic strength of the water phase, hence increase its surface tension, and enable it to be dispersed more easily, allowing the emulsion to be formed more easily
magnesium sulphate is generally used because it’s a cheap, readily soluble and non-toxic salt with a divalent cation; divalent ions increase ionic strength more than monovalent ones such as sodium do
in O/W emulsions, it serves no purpose whatsoever
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the first thing I’d do is try removing carbomer - it’s anionic, and guar hydroxypropyltrimonium chloride and polyquaternium-10 are cationic
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xanthan gum is anionic, it’s not compatible with quats
also, I’d get rid of the glyceryl stearate; BTMS/cetearyl alcohol is sufficient to form an emulsion, and in my experience with cationic emulsions, some non-ionics can thin this kind of product (not sure why, but it’s something I’ve observed with ceteareth-20 as well)
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@ultraduy they can’t be dissolved in water per se, but they are miscible with water; depending on where it comes from, bentonite is neutral to alkaline when mixed with water
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@Perry if the Daily Mail ever publishes anything which is a) factually accurate, and b) not keyed to incite hysteria, you can bet your bottom dollar it’s been plagiarised from somewhere else
also, cancer is a favourite subject of theirs; some helpful soul has compiled a list of things the Daily Mail reckons cause cancer
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it also depends how much work goes into developing it - the record so far is 130 hours (a little over two weeks’ worth of manpower) for a single formula, because the customer in question constantly moved the goalposts during the development process and, as happens more often than not on such projects, they only ever ordered the product once
the contract manufacturer I work for does release full formulas, but charges a substantial fee, between £3,000 and £5,000, to recoup the costs of the work undertaken
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your best bet is to send them off to an analytical lab for identification; individual dyes and pigments are chemically unique, and can easily be identified with the correct techniques
@Perry cosmetic colour suppliers in Europe generally sell FDA-certified (F)D&C colours, or colours that meet requirements for European food regulations
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@Doreen in practical terms 0.2% disodium EDTA is not ‘too much’, but for cold mixes it adds an awful lot of time to the process for very little added benefit; the reasons we add it are to increase the efficacy of the preservative system, and (for surfactant-based products) to ensure the products foams well if the consumer lives in a hard-water area, and it does both of these jobs very well at 0.1%
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@maria @Perry no worries, in a perverse kind of way I actually enjoy tearing apart stuff like this
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it goes into the water phase, but it takes a long time to dissolve at room temperature
also 0.05 - 0.1% is sufficient for the vast majority of products - 0.2% is a little excessive in my view
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that page is littered with factual errors, particularly the chemistry part; let’s take it apart bit by bit
first of all, throughout the text, the term ‘salt’ is used in place of the more specific (and more generally recognised) term ‘conjugate base’
“Lactic acid contains NMF”
NMF contains lactic acid, the converse is not true“AHAs have no known systemic toxicity”
on the contary, using glycolic acid as an example, a dose of 600 mg/kg is teratogenic (causes birth defects), and the NOEL for teratogenicity is 150 mg/kg“First and foremost, acid strength relates to the importance of pKa,
which is a measure of acid strength and free acid availability”
on the contrary, it is the pH at which the free acid and its conjugate base are present in equimolar amounts; it is nothing to do with actual quantity of acid present“The pKa is the logarithmic expression of the pH at which the acid
possesses ‘free acid’ containing equal amounts of ion and salt.”
1) pH is a logarithmic quantity by nature, and the fact it’s logarithmic is irrelevant in this context
2) salts are ions by definition, so the phrase ‘equal amounts of ion and salt’ is nonsense
3) see above for a coherent, non-garbled explanation of pKa
“Acids, bases, and salts contain ions of the element hydrogen.“
what is an “ion of the element hydrogen”?“The lower the pH the more active the acid peeling solution.”
not necessarily; if you put one drop of concentrated hydrochloric acid in a beaker of water, it will have a very low pH, but it will be a very weak acid“The more salt you have in your acid, the less potent it is”
correct (notwithstanding the use of ‘salt’ to mean ‘conjugate base’)
“and potentially the more irritating it can be.”
sources please?“The pKa value tells you at what pH you have half acid and half salt.
This translates that if you buffer an acid, you convert some of the acid
to the salt form.”
the first sentence is true, the second sentence makes no sense whatsoever“Acid solutions are “buffered” not to make the acid stable but to raise the pH.”
my head hurts“The concentration is not as important as the pH and the pKa. I am asked
all the time ‘what is the acid percentage concentration?’ Percentage of
acid concentration is irrelevant”
if this is right, then the laws of thermodynamics are wrong“and understanding this ‘acid chemistry’ explains why TCA, or
trichloracetic acid (pKa of .26) will be far stronger in a five percent
solution than lactic acid (pKa 3.86) or glycolic acid (pKa 3.83) at 30
percent. This is primarily because TCA is almost fully ionized and
lactic and glycolic acids are not.”
this is more to do with the chemistry of each acid than its strength; hydrochloric acid has a pKa of -7, and is therefore a much stronger acid than TCA, but it is much less corrosive to metals (and less toxic to life) because it has completely different chemistry
similarly, hydrofluoric acid has a pKa of around 3 (making it a weaker acid than TCA), but is a much more hazardous material, and is one of the few substances which can etch glass, due to its chemistrygod almighty, after reading that I need to lie down; the most depressing thing is that whoever wrote this probably got paid an ungodly sum for it
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@EliseCortes zinc forms a coordination complex with PCA; whether or not it will precipitate if phytic acid is present depends whether or not the complex with phytic acid is more stable than the complex with PCA, a question which I don’t personally know the answer to, and will most likely have to be answered by experiment
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regarding the first issue, are you using surface-treated pigments?
if not, have a look at the “Treated Pigments Powders” section on this page:
http://www.koboproductsinc.com/Products_Categories.aspxregarding the second issue, this always happens when liquids and coloured powders are mixed
also for what it’s worth, until a few years ago, cosmetic science was not generally taught in European universities either
the practical knowledge was (and still is) where the manufacturing base lies, and in my view it’s not something you can just learn out of a book; the vast majority of it is learned at the bench and in the factory
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the R&D section of our lab (which is also used for QC) is arranged in such a fashion that you start on one side and work your way over to the other as you carry out the process of manufacturing batches, so you have everything to hand and spend the least possible amount of time walking backwards and forwards between different parts of the lab
the balances are on one side, the hot mix area and Greaves mixer are on the bench next to them, the pH meter, viscometer etc. are adjacent to the hot mix area, on the opposite bench, and the sink is on the other side of the the balances, so you end up going in a circle (or more accurately, a parallelogram)