Bill_Toge
Forum Replies Created
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to be quite honest, I can’t think of a single preservative which wouldn’t be suitable for vegans
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Indian Standard IS 7159:1984 lists a number of test methods for henna powder, including testing for adulterants and extraneous sand - it may very well be helpful for your purposes
flame atomic absorption spectrocopy is most rigorous way to test for metals, but there are many qualitative methods too; for instance, certain dyes (methylthymol blue, xylenol orange, eriochrome black T) change colour in the presence of metal ions
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this is the full text of the opinion in question; the MoS calculations are on page 72 and 73
the conclusion is on page 83:
1. Does SCCS consider Phenoxyethanol safe for use as a preservative with a maximum concentration of 1.0 %, taking into account the information provided?The SCCS considers phenoxyethanol safe for use as a preservative with a maximum concentration of 1.0%, taking into account the information provided.2. The SCCS is asked, when making the assessment, to take into account the specific age groups who might be particularly susceptible to the effects of Phenoxyethanol used as preservatives in cosmetic products.The toxicokinetics default factor of 4.0 can be reduced to 1.0 yielding a minimum Margin of Safety (MoS) of 25 instead of 100 for the safety assessment of 2-phenoxyethanol. Therefore, the MoS of about 50 for children also covers this specific age group who might be higher exposed to 2-phenoxyethanol than adults. -
Basic Red 76 is poorly soluble in water; what else have you got in the formula?
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yes, ‘light’ and ‘heavy’ are generally used to refer to the physical sensations rather than the actual weight
the best explanation of molecular volume is an illustration:
space-filling model of stearic acid (unsaturated C18 acid)
space-filling model of oleic acid (monounsaturated C18 acid)(the black parts represent carbon atoms, the white parts represent hydrogen atoms, and the red parts represent oxygen atoms)
because it has two rotational axes rather than one, oleic acid takes up more space than stearic acid
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we have a container of sodium hydrosulphite in the lab… it’s the worst-smelling thing on site (even worse than the thioglycolic acid we use in perms), and because of this I’ve nicknamed it the Tub Of Death
the smell is so vile the technicians won’t even go near it
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the easiest way to achieve the result you want is to reduce the level of acid, and/or use weaker acids
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on a fundamental level, it’s due to the shape of the molecules
saturated and trans-unsaturated fatty acids adopt a linear configuration, which means they occupy a relatively low volume of space and can move freely
cis-unsaturated fatty acids, by their nature, can only adopt a cuneiform (wedge-shaped) configuration, because the double bond is completely inflexible, so they occupy a much larger volume of space than linear fatty acids and cannot move as freely
as a result, they have higher melting and boiling points than the linear fatty acids with the same carbon chain length, and are usually liquids at room temperature; the linear fatty acids with the same carbon chain length are usually solids, which gives them a different skin feel
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somebody will have experience with that kind of product, yes
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if you’re talking about the kinematic viscosity, measured in centistokes, the ‘ideal’ value depends on what kind of effect you’re trying to achieve
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when it comes to preventing oxidation, the easiest way is to exclude as much oxygen from the packaging as possible; the best way to achieve this in practise is to fill your product into an aluminium tube
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apropos of nothing, the human nose is extraordinarily sensitive to grapefruit mercaptan; it can be smelt in the parts-per-billion range
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anything which moderates the action of vanillyl butyl ether can only be a good thing
I can vividly remember putting one drop of it on the back of my hand and feeling nothing at first, but after a few minutes my hand felt like it was on fire; although there was no evident irritation or inflammation, the feeling persisted for several hours afterwards
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in a W/Si emulsion the continuous phase (silicone) is non-conductive and non-protic, so it doesn’t have a pH; or rather, any reading obtained on a pH meter is meaningless
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but hydroxypropyltrimonium guar is a quat
the full name for it is “hydroxypropyltrimethyl ammonium guar chloride”; granted, it is a mouthful, but shows its true nature
@Belassi my best guess is that the level of residual impurities (unreacted monomers, which are much more harmful than the finished polymer) is not routinely tested on Rheovis CDE, and for that reason, a company as large as BASF is not willing to sell it for direct human-use applications without some kind of assurance that it’s safe for that purpose
however, the fact they sell very similar products specifically for human use means that the demand for human-use Rheovis CDE is insufficient for them to consider implementing those extra process and QC checks, so they play it safe by restricting its sale for use in laundry products only
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@Doreen technically it is, but the question is how volatile
in this paper, the authors recorded the vapour pressure of phenoxyethanol as 0.7 mmHg at 84.5°C and 19.4 mmHg at 135°C
for comparison, the vapour pressure of water at 85°C is around 430 mmHg (and atmospheric pressure at sea level is around 760 mmHg)
although its vapour pressure is very low at room temperature, the fact it can be smelt implies the human nose is very sensitive to it
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the European Parliament does not take these matters lightly; they employ expert committees in order to make a properly informed decision (and prevent lobbying), and if they do impose restrictions, there will be hard scientific evidence behind them, which will be made available for public viewing
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if you’re happy about buying chemicals from China, several sellers on Alibaba have a minimum order quantity of 1 kg
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@PeiHoong taking an educated guess, it’s most likely the combination of Hydrogenated Polycyclopentadiene, Ethylene/Propylene Copolymer and microcrystalline wax, and the fact there’s very little water in it
do you have the equipment and reagents to do a Karl Fischer test? that’ll tell you exactly how much water there is in it
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is the entire product going dark, or just the surface?
is the discoloration uniform, or does it just happen in irregular patches?
if possible, a photo would be very helpful
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@medaura all you need to know can be found in this manufacturer’s brochure
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it’s not an emulsion, it’s an oil-based suspension
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salt also brings you good luck if you throw a pinch of it over your left shoulder
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besides generic polymers like PVP and VP/VA copolymers, there’s a huge range of styling resins available; BASF, Ashland and Akzo Nobel are the big players in the market
a combination of hard waxes and volatile oils will give you the dry texture - formulating water-based styling products is a subtle art, as it’s one of the most complex product types you’re likely to come across
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in W/O and W/Si emulsions, salt increases the surface tension of the water phase, allowing it to be emulsified (and stay emulsified) more easily