Bill_Toge
Forum Replies Created
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I would say no - salt’s not known for causing electrostatic discharges, and in any case, that’s only a risk when you’re handling flammable materials in the same space
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it does go yellow, but not usually that quickly - what’s the ambient temperature where your samples are?also, how old is your formalin solution? depending on the age, it may contain oligomers and other impurities
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try Versagel
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@Svemirska_baklava nice to see another hot-fill styling product veteran on here!
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adding it then mixing it at low speed works best, it minimises the amount of trapped airback-acid thickening allows you to get the maximum benefit - you have to neutralise the polymer to pH 7-8, then ajust the pH downwards to your desired range with acid(also, SF-2 does the job better and is more acid-tolerant)
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water has a higher vapour pressure at 40 °C than it does at room temperature - what’s happening is that some of it is evaporating, then condensing on the inner surface of the lid, which a natural consequence of storage at higher temperatureson the plus side, it shows your closure seals tightly - condensation is better than having the water escape through the gap between the lid and the container, and having the product dry out
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@PhilGeis the fact that neither 5,5-dimethyl hydantoin (the parent compound of DMDM hydantoin, minus the two formaldehyde equivalents) nor p-hydroxybenzoic acid (the parent compound of parabens) have any microbistatic or microbicidal activity is pretty strong evidence
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I can’t vouch for their effectiveness with benzoyl peroxide, but in my experience, sodium stannate and etidronic acid work well to stabilise hydrogen peroxide, as does keeping the pH below 4
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it releases formaldehyde when microbes attempt to ingest it, in the same way that parabens release alcohols when microbes attempt to ingest themit also starts to release formaldehyde in alkaline conditions, or when exposed to temperatures over around 50-60 °C
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it won’t, because the amount of active preservative in the raw material is around 55% - the rest is water, so it would contain the equivalent amount as 0.055% formalinalso, the amount of free formaldehyde is considerably less than than that (1% at most), as the rest of it is bound to the DMDM hydantoin molecule (the two -CH2OH groups attached to the nitrogens) and is only released when microbes attempt to ingest itso the actual amount of formaldehyde in solution is equivalent to 0.00055% formalin at most
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how much tocopherol are you using, and what’s it derived from?depending on the source and the amount, that can turn very brown - in my experience, soy-derived vitamin E is more susceptible to browning than wheatgerm-derived vitamin E
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congratulations, Perry!
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it looks like a lot of air was trapped within it during the manufacturing process, and it’s now starting to come outhigh-shear mixing is best kept to the absolute minimum necessary to form the emulsion, and it’s best to keep the head of the mixer entirely below the surface of the liquid, or else you end up with problems like this
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Omnibus III limits its use in face powders to 25% w/w, if more than 1% of the particles are smaller than 10 microns - it doesn’t prohibit it
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if it’s hydrophobic, a pH measurement will be in no way usefulpH is only meaningful with powders that dissolve in or are miscible with water
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depends whether the dyes are oxidative (permant/demi-permanent) or direct (semi-permanent)in the former case, the dyes are entangled within the structure of the hair itself and have very little effect, while in the latter case, this depends on the individual dyes in the formulation - some are much more wash-fast than others
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it depends how much you’re planning to make at any given time - a planetary mixer for industrial catering works well from a few hundred grams up to a few kilograms, while for larger quantities, a ribbon blender is the most efficient tool for the job
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in a previous job I have seen styrene/acrylate copolymer type opacifiers settle in the presence of excessive salt; our solution was to source an opacifier that was more robust towards salt, namely Rohm & Haas/Dow’s Opulyn 305
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the K-value is proportional to the viscosity, which is higher in water than it is in alcohol, because water forms much stronger bonds with its solvates than alcohol does, so comparing the two values is not meaningfulthe best way to compare the two directly is to make up the finished product with each material and determine whether there’s any difference
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Pharma said:Phenolic antioxidants such as tocopherol will not rescue vitamin C but show in vivo synergism. The former are also better at capturing the causing agent (oxygen) and don’t just ‘remedy’ damage or quenche chain reactions.and water-soluble benzophenone derivatives work on the same principle - they form relatively stable radicals, more readily than phenolic species (the radical is stabilised by two aromatic rings rather than one, and is physically very hindered)they’re certainly effective against dye degradation by UV-generated radical species, so in principle they should be similarly effective against reactive oxygen radicals too
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there’s no difference - they’re two different terms for the same material
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it’s also very prone to oxidation in water-based formulas, and turns them brown over time - I’ve only ever used it for preserving hygroscopic powders
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sodium metabisulphite is good at slowing down oxidation of vitamin C, and in principle, benzophenone-4 could act as an efficient radical trap for oxygen(disclaimer: I’ve not actually tried the latter)
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quite a few FD&C dyes are acid stable - FD&C Blue 1, FD&C Red 40/Food Red 17, tartrazine/FD&C Yellow 5, Sunset Yellow/FD&C Yellow 6, to name a few
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the European ban is to restrict its usage to medicines only - same story with benzoyl peroxide, tretinoin and hydroquinone