Bill_Toge
Forum Replies Created
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given that it contains triethanolamine and stearic acid, and TEA is listed above phenoxyethanol (typically around 1%), I’m willing to bet it contains a significant amount of TEA stearate, which is a kind of soap; therefore, it could potentially have a cleansing action
surprised it doesn’t contain any isethionates though, those are the backbone of all the Dove products I’ve come across to date
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can’t speak for the rest of Europe, but manufacturers in the UK generally don’t offer internships; your best bet is an entry-level position or a short-term contract job, e.g. covering someone who’s on maternity leave
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@Doreen never had a problem them; chelators only affect dissolved metal ions, and the metal oxides in question are a) insoluble and b) coated onto the mica, making them particularly difficult to dissolve even if they were soluble
@Chemist77 similarly, zinc pyrithione is insoluble in water, so there are no (or nearly no) zinc ions present
trivia time: the first discovered fungicide of this kind was sodium pyrithione, but it proved to be toxic to the point of impracticality due to its high solubility in water, which is why the zinc salt is used instead
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just for the record: fatty alcohols are surface-active, and have a significant effect on emulsions as a result, but they do not act as emulsifiers
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@Belassi and of course, you have to make sure it kills the Hungarian car-eating muppet
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@Microformulation I found cetyl/stearyl alcohols thin very readily under shear, and don’t contribute much to the skin feel of the product
@JOJO91343 is this assertion based on your personal experience?
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I agree with @maria, it’s most likely your ultramarines that are causing the smell; there’s no other obvious cause for it
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@Zink I was being facetious
alkyd resins make paint stick to hard surfaces; they don’t even have INCI names, let alone adequate toxicology data to prove that they’re safe for human use
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for what it’s worth, I did an extensive experiment a few years back and found that cetyl/stearyl alcohols increase the viscosity of the proruct at low shear (i.e. make the product more rigid and less fluid), while stearic acid increases the viscosity at high shear (i.e. makes the product feel more ‘creamy’)
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the expiry date is the latest date the supplier can guarantee their material is fit for use, based on the results of their QC testing
this doesn’t necessarily mean the material is unfit for use after this date, it just means further QC testing will be required to extend the guarantee
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@Belassi a major multi-national haircare brander, who used to subcontract the manufacturing of one of their products to our site because it was literally impossible to make on their own plant (their minimum batch size was relatively large, and the product would separate part-way through the production run on their site), outsourced this product to a new plant they acquired abroad, and even though the product name and INCI list has not changed, the product made at this plant is as different to the one we made as chalk is to cheese, and anyone with eyes and fingers can tell it’s not the same stuff
what I’m trying to say in that wall of text is that no, lists of ingredients are never 100% reliable, regardless of where they come from
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if your name, or your company’s name, is on the pack, that makes you the Responsible Person by default - as the Responsible Person, you are legally obliged to have this information to hand in case someone comes to harm from using your product, and the Competent Authorities (Trading Standards Agency in the UK, and equivalent agencies in other countries) need to investigate
@paulasbrito the only person who has to have any particular qualification is the safety assessor; they need to have a background in toxicology, and preferably have professional accreditation as well as an academic qualification
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salicylic acid works best between pH 3 and 4 - if the pH is lower than 3, your product would be classified as a skin and eye irritant
also, adding citric acid has little if any effect because there is already a large amount of a much stronger acid present
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salicylic acid is soluble in surfactant solutions - you’ll have to heat it up to dissolve it, though, and it does take its time dissolving
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@Chemist77 the minimum inhibitory concentration for most microbes is a few parts per million; if you’ve got significantly more than that, and no anionic surfactants, an extra preservative is usually unnecessary
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if you valued product performance above ethics and regulatory acceptability, a small amount of alkyd resin would most likely do the job
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this is another example of received wisdom where (apparently) nobody has asked why or how it occurs, or tried it for themselves to see whether or not it’s true
personally, I have never witnessed it, and my view is that if an emulsion can be destabilised by something as inert and sparingly soluble as phenoxyethanol, it’s nowhere near robust enough to be fit for use in a consumer product
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you need to kill any bacteria present, and only the most aggressively antimicrobial preservatives (e.g. chlorhexidine) will do that; irradiation is the easiest way to kill bacteria without spoiling the product
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it’s called Simulgel NS, and it’s sold by Seppic; I work for a UK-based firm, and we’ve never had any problems getting it from them
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speaking from experience, you’ll want a preservative to stop yeasts and moulds growing in it
out of those emulsifiers, my personal choice would be a combination of GMS/PEG-100 stearate and polyglyceryl-3 stearate (high and low HLB, plus the GMS is acid-stable)
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you don’t need to use HPLC; if you’ve got a mercury-vapour UV lamp, any organic adulterants will be visible on a thin-layer chromatography plate
if you have pure henna, the only substances visible on the plate should be lawsone (Rf = 0.4) and chlorophyll (coincident with the solvent front)
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the absolute minimum I’d suggest doing would be to get it dried to powder form and irradiated, so it’s sterile and doesn’t act as a vector for microbial contamination; this would also solve (or at least, significantly reduce) the problem of degradation
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@Khadijah the standard is available to anyone who pays for it, e.g. here
regarding the ‘compatibility test’: the mixture will become coloured if there are oxidative dye precursors (e.g. PPD, resorcinol) present
in my experience these are the most common additives/adulterants in ‘natural’ henna powder, and can be detected by the thin-layer chromatography method described in the standard
if you can get a sample of pure lawsone (the active colourant in henna; systematic name 2-hydroxy-1,4-naphthoquinone, CAS # 83-72-7), make a 1% solution of it in water and test that solution under the same conditions, you’ll know for sure whether or not the ‘compatibility test’ is valid
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also, for what it’s worth, the synthetic mica substitute frequently used as a pigment is spelt fluorphlogopite
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@Doreen simple, we use our latent powers of telepathy
