[Bill_Toge]

my two pennorth: the only time I’ve ever seen EGMS/EGDS pearls separate is in glass containers (notwithstanding formulas that were generally unfit for use); the fact that it could reliably be reproduced in glass, and was not all reproducable in any type of plastic container, strongly suggests that the interfacial properties of glass play a part in destabilising it

also, if EGMS/EGDS does separate it’ll rise to the top of the container rather than fall to the bottom and appear as sediment, since they both have a lower density than water

[Bill_Toge]

Euxyl PE9010 is an exceptionally reliable preservative in appropriate products; it’s best suited for creams and lotions as its solubility in water is low

also, avoid using it in surfactant-based products (shampoos, shower gels etc.) as its efficacy is reduced

Lonza’s Glydant Plus is substantially water-miscible and is also very reliable, though as with Germall Plus, you can’t use it in products for children under 3 within the EU, because it contains iodopropynyl butylcarbamate

[Bill_Toge]

for what it’s worth, tattoos have never stopped my boss finding work; he has 25 years’ experience in the cosmetics industry and 13 years in the pharmaceutical industry, both on the shop floor and in the lab

[Bill_Toge]

if you’ve got large amounts of clay in your formula you’ll need something substantially water soluble (i.e. not phenoxyethanol) or else it’ll adsorb onto the clay and be rendered ineffective; the only time I’ve ever seen Euxyl PE9010 fail a challenge test was in a formula with 20% clay in it

Suttocide A, sodium hydroxymethylglycinate, is supposed to be effective at high pH, though I’ve not used it myself

[Bill_Toge]

Lubrizol don’t usually do direct sales in small quantities; they have local distributors for this

quaternised guar gum will have a significant effect on conditioning and moisturising; there is a particular technique which needs to be followed to disperse it successfully, which is why I initially suggested leaving it out to keep things simple

[Bill_Toge]

it’s quite possible to create a water-soluble styling paste with a similar thickness and consistency to petrolatum, but it’s not a straightforward process and the chances are you’ll need to do a lot of experimenting to get it just right

[Bill_Toge]

for a pearl effect, the simplest way, and the way many commercial manufacturers do it, is to use a pre-mixed pearliser blend (there are many available from assorted chemical suppliers)

you can try adding it the old-fashioned way, but you’ll have to melt your glycol distearate first, and ensure the main batch is hot enough for it not to crash out; for best results you’ll also need a rotor/stator shear mixer, as a blender will aerate it

sodium chloride is neutral, it won’t affect the pH

[Bill_Toge]

making a styling gel, combining the carbomer and PVP premixes to form a finished product that’s unlike either of its constituent parts, always got some interest at exhibitions

[Bill_Toge]

the most useful thing to do here is to take a step back, and work out whether it’s a formulation issue or a method-of-manufacture issue

leave out your glycol distearate, polyquat-7 and guar hydroxypropyltrimonium chloride (these are the ingredients which necessitate a more complex method) and try again, without heat

you don’t need to use a blender or a shear mixer to mix shampoo; in fact, you could mix it by hand if you’re patient enough

also, 1% citric acid will make it incredibly acidic, and this will not help the viscosity - try 0.1% instead

[Bill_Toge]

going by the MSDS for the Brazilian Blowouts product, it appears the magic ingredient is Hydrogenated Castor Oil / Sebacic Acid Copolymer, also known as Crodabond CSA

it looks like it’s designed to achieve a similar result using different technology; whether or not it actually achieves this result I can’t say, not having used either product

[Bill_Toge]

given that you’ve shown them actual physical evidence of your ability to formulate products (hence, an indication of your work-related competence), I’d say they’re sensible to put you on the shortlist

related: when I was 17/18 I was living in sub-breadline poverty and really couldn’t afford to go to university; my first job in this industry (age 23) was entirely based on the strength of several years’ experience as a QC technician in a related industry

[Bill_Toge]

@Chemist77 also, the SCCS have recently taken a poor view of methylene glycol in hair straighteners (link here), because when the hair is heated, either by blow drying or by application of straightening irons, it releases formaldehyde vapours at well above the maximum safe level

[Bill_Toge]

have you run freeze/thaw tests on it? and if so, does the same thing happen after several freeze/thaw cycles?

if it can’t be reproduced in freeze/thaw tests, it’s most likely a side effect of being stored at high temperature, rather than a sign of intrinsic instability

[Bill_Toge]

@bobzchemist chances are the “natural is always safe and better” crowd would ignore it and sweep it under the rug, as it flies in the face of their ideology

for instance: there are 30+ naturally occurring plants and fungi on the EU banned list, all for very good reasons (toxic and/or pharmaceutical), yet most of the people who preach that message in Europe are either blissfully unaware of this or choose to ignore it!

[Bill_Toge]

@manstra, on the contrary, your dispersed phase is oil and your continuous phase is water, hence: oil in water

whether an emulsion is O/W or W/O has nothing to do with the relative volumes of the two phases, and everything to do which emulsifiers you use; and @Iaskedbetter is right, Tweens are far too hydrophilic to act as W/O emulsifiers

you’re right about the two lipophilic parts coming together, but that does not make it a double emulsion - if you have multiple surface-active materials on the same interface, it’s still a single emulsion 

the diagram below shows a W/O/W emulsion (blue = water, yellow = oil, white = emulsifier)

and this diagram shows the system you’ve made (blue = water, yellow = oil, white = Tween 20, orange = glycol distearate)

hope this helps!

[Bill_Toge]

first of all, W/O/W emulsions are somewhat specialist, difficult to make, and very unusual in cosmetics; if memory serves, L’Oreal have a number of extant patents related to their usage in cosmetic products, so if you’re planning to make this a commercial product at any point I’d strongly suggest you do a patent search, and find out what you can and can’t do

secondly, W/O/W is a water-in-oil emulsion emulsified into water, which is not what you have there; phase 2 is an oil-in-water emulsion 

[Bill_Toge]

my initial suspicion is that your Optiphen and/or dimethicone are separating

rather than trying to fix this with a solubiliser I’d suggest using a more water-soluble preservative (e.g. DMDMH) in place of the former, and a water-miscible silicone (e.g. DC 193) in place of the latter

[Bill_Toge]

in the context of a hair gel, “resin” usually mean PVP or a similar polymer; I’ve never heard carbomers described as resins

[Bill_Toge]

there’s a couple of big firms in Bradford, one of which I used to work for, and who occasionally used to take on work experience folk in the lab

I know of a few smaller, more specialist firms in Darlington, Hull and north Manchester, but don’t know what their position is regarding temporary lab staff

if you’re interested, PM me for details

[Bill_Toge]

try using soluble starch, if you can find any that meets the criteria for tier 1 or 2

[Bill_Toge]

Ultrez 20 is a good one as well

[Bill_Toge]

most UK manufacturers don’t really take on temporary lab staff in the way you want; in my view, your best bet is to start with a basic lab role at a big private label/own brand manufacturer, that way you can get some initial training, along with a sufficiently broad range of experience to find out what you like and don’t like

problem is, you’d have to travel a long way to find a job like that - I don’t know of any such companies in Scotland

[Bill_Toge]

if it’s a hot mix I’d cool it to room temperature before capping it, and avoid storing it anywhere with widely variable ambient temperatures

(this is what we do with water-based hot fills in production)

[Bill_Toge]

yes, I’m happy to be a guinea pig for my own products, except where it’s not practical to do so (e.g. my hair is too short to style or comb, so I can’t meaningfully evaluate conditioners or styling products); it also helps that I have no known allergies 

in contrast, my old boss wouldn’t even consider using anything until it had been run through all the tests and safety assessed, but by her own admission she was something of a hypochondriac

[Bill_Toge]

how much beeswax, and how much olive oil?