[Bill_Toge]

legality aside, the fundamental problem is that water-soluble dyes are the wrong type of colourant for colour cosmetics; what you need is a pigment

[Bill_Toge]

if you choose a low-viscosity/non-polar oil as the major solvent, it won’t

[Bill_Toge]

Perry said:

2.  Regulations - These are not made based solely on scientific data. If they were, there would be no differences in regulations anywhere in the world. If safety was the highest concern, professional toxicologists would be the only people involved in deciding what ingredients are safe and at what level. But it’s not done that way. Non-scientists & industry are involved in creating regulations and they come to conclusions that are not necessarily science based.

…more to come.

don’t know about the rest of the world, but in Europe any proposed change to the legislation must first be reviewed by the Scientific Committee for Consumer Safety, a panel of expert doctors and toxicologists from all over Europe, and any changes must be made in accordance with their advice

this makes European cosmetics legislation exceptionally resistant to lobbying, and is the reason why it’s still legal (though impractical and commercially suicidal) to use formaldehyde as a preservative in Europe; within the usage limits dictated by Annex V, it’s been found to be safe for use

[Bill_Toge]

they certainly can

whether dishwashing detergent-grade dyes can be used for food is quite another matter

[Bill_Toge]

hydrogenated castor oil/castor wax is good at gelling oils and enabling them to suspend solids; try it and see how you go

[Bill_Toge]

Snowman said:

@Bill_Toge Thanks! That certainly looks like an avenue worth pursuing. I started looking around for this and it appears to be very hard to find in Australia. It seems its also called 12-hydroxystearic? My searching turned up stearic acid which seems to be very easy to get, but looking at the makeup of it it appears marginally different. Are these 2 interchangeable by any chance?

it’s 12-hydroxystearic acid; stearic acid is completely different and doesn’t have any capacity to form a gel

also polyhydroxystearic acid is a different thing from both of these and has no capacity to form a gel either

[Bill_Toge]

Doreen said:

ngarayeva001 said:

(…) having in mind that the product will gain final viscosity only after a couple of days.

I’ve seen this brought up many times, that you gain final viscosity only after a day or 2 if you use fatty acids/alcohols, but I’ve never experienced it myself. Viscosity right after cooling down has always been the same as a few days later. And I’ve made quite some creams with cetyl/stearyl alcohol and the likes.

Isn’t that what’s been described not actually a cream drying out? How is the packaging? A jar? 

this happens in sealed containers at low temperatures (if anything, low temperatures accelerate it); water has low vapour pressure at room temperature and below, so not enough of it can escape to cause a significant drying effect

[Bill_Toge]

in a word, no; you have to find out what level is best for your desired application by experiment or past experience

[Bill_Toge]

also, all but the most robust emulsions will rapidly destabilise at that temperature

[Bill_Toge]

ngarayeva001 said:

You need to account for this effect when you formulate that’s it. Add less fatty acids/alcohols in your formula having in mind that the product will gain final viscosity only after a couple of days.

+1 for this; it’s controlled by thermodynamics and can’t be prevented

[Bill_Toge]

hydroxystearic acid gels are not temperature-sensitive

[Bill_Toge]

@Kanuck if you use refined shea butter the crystallisation problem can be severely reduced/eliminated

[Bill_Toge]

ask for references from some of their existing customers

[Bill_Toge]

VP/VA copolymer comes in several different grades - which one did you use?

you’ll get better and more consistent results using a more hydrophobic polymer, e.g. un-neutralised Amphomer

also, regarding your silica dimethyl silylate, what is the surface area per gram, and how does that compare to Aerosil R 812 S? (the value should be in the technical documents)

[Bill_Toge]

it should be OK, though it may be less viscous as the alkyl chain is shorter (C18 vs. C22)

also, stearalkonium chloride is not a kind of benzalkonium chloride; it is strictly aliphatic and does not have any benzene rings in it

[Bill_Toge]

if you want to use sodium benzoate you’ll need a secondary, non-ionic emulsifier (e.g. ceteareth-20), both for increased electrolyte tolerance and for stability

[Bill_Toge]

asafvarlix said:

Dear Perry & Bill, Bill got that precisely right -
Its happening with Cetyl alcohol, stearyl alcohols and stearic acid.

What’s the “name” of this phenomenon - should one exist?

a technical description would be that the surface-active waxes initially exist in a kinetically stable/metastable non-equilibrium phsyical state within the emulsion, then recrystallise into their most thermodynamically stable state over time

[Bill_Toge]

try gelling the oil with hydroxystearic acid; at a sufficiently high percentage (5% or more) it’ll make the oil close to solid

[Bill_Toge]

I had a sense of deja vu reading this, and sure enough, we had a thread on this author a few months ago:

https://chemistscorner.com/cosmeticsciencetalk/discussion/comment/37292

@lewhitak the other thing to bear in mind is that industrial chemists and academic chemists are completely different beasts; due to the nature of their work, (good) industrial chemists acquire a very broad knowledge base comprising significant elements of engineering, microbiology and human psychology

by contrast, academic chemists tend to be narrowly focussed and highly specialist

[Bill_Toge]

ngarayeva001 said:

I spend hours on incidecoder reading LOIs (I know that their notes on whether an ingredient is goodie or not are irrelevant, I just like the format of having all in one place). Work of other people (and especially a successful one) is a never-ending source of inspiration. 

assuming the LOI is accurate - in the days when I used to try and replicate hot-fill styling products, the benchmarks often had fundamentally inaccurate LOIs, and until I started ignoring their LOIs altogether they were the indirect cause of much wasted time and premature greying

[Bill_Toge]

if you mean the increase in zero-shear viscosity that occurs on standing for 12-24 hours, that’s a result of the surface-active waxes (cetearyl alcohol/stearic acid) recrystallising into their most thermodynamically stable state following formation and cooling of the emulsion

[Bill_Toge]

Perry said:

Sure, it’s pretty easy to knock-off or duplicate an existing formula. Unfortunately, the performance and quality of a formula is rarely related to how much you can charge for it.  That is all about marketing.

though it doesn’t hurt at all if there’s a well-performing product behind the marketing, as I found out when a product I’d developed for a third party was sold onto another brand owner (who were much better at marketing their products), and it went from being an obscure curiosity to one of our highest-turnover products within the course a month

Pharma said:

Wouldn’t it be fairly easy to reverse engineer a cream simply by using chromatography (HPTLC/HPLC/GC) and mass spectroscopy? Depending on composition (cause polymers and extracts are not so easy going) and given that you have concentration curves of reference compounds, the bulk could be copied within an hour.

it’s quicker and easier to play it by ear/hand/nose/(insert other sense here), and reverse-engineer it by comparing it to a known formula, and altering that formula to fit

[Bill_Toge]

instead of emulsifying wax NF, try an emulsifier with an electrolyte-tolerant co-emulsifier with a long chain, e.g. PEG-100 stearate or polyglyceryl-6 behenate

alternatively, instead of magnesium sulphate try using magnesium oxide (less water-soluble)

[Bill_Toge]

this is a well-known ‘feature’ of sorbate salts in water-based products; they’re best suited to dry/hygroscopic products

[Bill_Toge]

it will vary depending on the grade of HEC you’re using, and how thick you want the finished product to be