[Bill_Toge]

chances are it’s mixed in with phenoxyethanol and glycerine, which in turn are mixed into the rest of the product

@David08848 depending on the supplier, a number of lake pigments contain aluminium hydroxide, which is most likely where it’s come from

[Bill_Toge]

@em88 I doubt it; to me, this claim looks very much like superstitious nonsense

[Bill_Toge]

try hydroxypropyl cellulose

[Bill_Toge]

what you need is an intermediate solvent that is miscible both with beeswax/coconut oil, and with IPA

try using an ester of some kind

[Bill_Toge]

that’d be a toxicological safety report as specified in Annex I of Cosmetic Products Regulation 1223/2009 EC

we usually use EF Chemical Consulting in the UK for safety assessments; they have reasonable prices, take a sensible approach, and have a quick turnaround time

[Bill_Toge]

my prime suspect is xanthan gum, as it’s a film former; try reducing it, or using another rheology modifier in its place

[Bill_Toge]

Higher pH numbers in such a case would increase salt which counter-intuitively would make the formula even more irritating than if the formula was more acidic.

that’s a new one on me; have they cited any sources for this claim?

[Bill_Toge]

@Doaneventry the lake is insoluble; the dye is not

[Bill_Toge]

yes/no

(delete as applicable)

[Bill_Toge]

what we could really do with is some kind of study investigating how the measured SPF correlates to the elastic modulus and/or cone penetration of a formula, since those are the other major factors which affect it in practise

in my experience the BASF simulator tends to underestimate the actual in-vivo SPF value, and conversely, Labspheres tend to overestimate it, though both are generally accurate when it comes to UVA/UVB ratios

[Bill_Toge]

you can get D&C Red 30 as a dye, as opposed to a lake; it’s soluble in polar oils

[Bill_Toge]

depends where in the world you’re planning to sell it, and what view the local authorities take on hormones

in Europe, for instance, hormones are restricted to medicines only, and for good reason

[Bill_Toge]

could also be due to the slow evaporation of water over time; this type of product generally doesn’t contain much water and is relatively solid, so it’s very prone to evaporation

[Bill_Toge]

@em88 @Chemist5000 those are water-soluble, so they won’t work in this type of product

[Bill_Toge]

any oil with a similar viscosity and vapour pressure (i.e. volatility) as squalene will do the same job; in chemical terms, it’s nothing special

[Bill_Toge]

the root cause of the problem is that you don’t have anything in the mixture which can chemically or physically emulsify the oil into the water; you need a surface-active material of some kind

[Bill_Toge]

at a guess, the fact there are no salts that can act to stabilise the pH; something as simple as disodium EDTA can be very beneficial in this regard

however, my bigger concern is that there appears to be no preservative

[Bill_Toge]

in my experience the single ‘natural’ (i.e. refined rather than synthesised) material which has the widest range of variation is Petrolatum, and even then the specification only gives you part of the picture

from a sensorial point of view, a very important physical parameter is the cone penetration, which is a quantitative measure of how hard the material is, and a given manufacturer’s grades are usually differentiated on this basis

however the other, equally important key quantity is the elastic modulus, which generally isn’t measured, so in practise you have to evaluate different grades by physically comparing them side by side

the most widely variable fully synthetic material is Acrylates Copolymer, which is a generic term which covers anything from opacifiers to rheology modifiers to waterproofing agents

[Bill_Toge]

depends on the company’s capabilities; for us, 100 gallons (454 litres) would fill our smallest vessel nearly to the top, and the smallest batch of hot-mix product we can make is around 200 kg

with cold mixes we can go smaller still, and with some very simple, low-viscosity products (e.g. body oils) we can even mix them in a barrel if push comes to shove

[Bill_Toge]

for what it’s worth, both methods are variations on the same basic technique: slowing down the hydration of the gum by pre-dispersing it in a medium in which it cannot be hydrated

[Bill_Toge]

can’t see anything in there that would have a preservative effect - in fact, what I do see is an awful lot of bug food (sugar, honey, guar gum)

assuming that ingredients list is accurate, the only realistic possibility for self-preservation would be if the product is very acidic, i.e. with a pH less than 3

in my view they’re being breathtakingly reckless by selling a product which has such a high potential for microbial contamination

[Bill_Toge]

also, one of our sales staff has a habit of pronouncing ‘micellar’ as ‘micular’… in unrelated news, my desk has a forehead-shaped indentation in it

[Bill_Toge]

I’ve always thought that ‘dry’ refers to the after-feel rather than the oil itself; ‘volatile low viscosity oil’ would be more rigorous description

‘chemical free’ hasn’t caught on over on this side of the Atlantic, because it is blatantly false (both in the scientific and legal sense) and the Advertising Standards Agency cracks down pretty hard on that kind of thing

[Bill_Toge]

my prime suspect is PEG/PPG-20/23 Dimethicone (Silsoft 430 / Silsoft 440); most likely, it does the donkey work of actually volumising the hair while the panthenol, caffeine and nicotinamide are included mostly for marketing purposes

[Bill_Toge]

if the cracking is random and not consistently reproducible, it does strongly suggest the problem is caused by the workmanship of the packaging rather than the material itself

a systematic incompatibility between the formula and the packaging material would affect all the packs tested, rather than around 50%