[Bill_Toge]

blimey!

as Henkel are a major brander, this is a huge balls-up on somebody’s part

preservatives notwithstanding, this could just as well be down to inadequate hygiene and sterilisation on site as anything else; I used to work at a factory which had had an infamous contamination incident a few months before I’d started, and although the contaminated products had passed challenge tests with flying colours, they were very prone to B. cepacia contamination

Perry said:

@Window - You are mistaken about formaldehyde donors being banned in the EU.  They aren’t.  The ban applies to formaldehyde & methylene glycol. Things like DMDM Hydantoin, Imidazolidinyl Urea, etc. are perfectly fine. http://ec.europa.eu/growth/tools-databases/cosing/pdf/COSING_Annex%20V_v2.pdf

in fact, according to Annex V/5 it’s still perfectly legal to use formaldehyde as a preservative, at up to 0.1% in oral care and 0.2% in anything else apart from aerosols; this is simply because there is no evidence it’s harmful at those levels, and the SCCS makes the legislature exceptionally resistant to lobbying

however, in practise no-one actually uses it because given the bad press it’s had, it’d be commercial suicide to do so (it’s also terrible for turning products yellow or brown)

[Bill_Toge]

have a look on ebay and Alibaba - there’s an extraordinary range of machinery for sale

for what it’s worth I’d suggest going with semi-automatic to start with, unless you’re making very high volumes; more heavily automated a machine is (hence, the more complex), the harder to maintain and the more expensive it gets

[Bill_Toge]

that depends, are you a home crafter or an industrial user? even for industrial users, it’s a compact system; it only takes up a few square feet of floor and wall space, and a system for home users will be smaller still

this is an industrial system I’ve set up recently, with the help of a local plumbing firm; the ion-exchange column is on the right of the picture, and the UV lamp is the silver tube mounted on the wall

also, there shouldn’t be any chlorine at all in mains water - if you’re worried about it you can buy strips to test the level

[Bill_Toge]

silly question, but did you adjust the pH to 5.5 - 6.5?

[Bill_Toge]

in my experience hydrophobically coated starches (e.g. Agenaflo 9050 from Agrana Stärke GmbH) work well for this

besides these, there are a number of silicone-coated powders which do the same job, and are used in many commercial products

[Bill_Toge]

phthalates are not preservatives: they are used as solvents (e.g. in fragrances) and plasticisers for polymers, and can act as fixatives in fragrances

dimethyl and diethyl phthalate are odourless and harmless, but the longer-chain analogues (dibutyl, diethylhexyl etc.) are known teratogens, and within Europe they are banned from a number of products including cosmetics and toys - many Chinese-made toys are taken off the market or turned back at the border every week due to their phthalate content

[Bill_Toge]

if you want to deionise your water, the most economical way is to use an ion-exchange column in conjunction with a UV lamp; it’s a lot cheaper and more portable than reverse osmosis

the upper limit for conductivity depends on what you’re using the water for: if you’re using metal-sensitive materials like hydrogen peroxide or thioglycolic acid, or you’re making surfactant-based/oral care products, you want it as low as possible (ideally 5 μS/cm or less), but there is some leeway elsewhere

also, chlorine (with an oxidation state of 0) is an oxidant and causes colour fade - chloride (with an oxidation state of -1) is the reduced form of chlorine, and is generally inert

[Bill_Toge]

what you need is a surfactant-tolerant carbomer, e.g. Carbopol Ultrez 20/21; as you’ve discovered, HEC won’t help suspend particles

if you go down this route I strongly suggest taking out the quaternised guar as well, it’ll make things a lot simpler

[Bill_Toge]

yes

[Bill_Toge]

Gunther said:

Thioglycolic acid has both sulfur, and a particular smell, although I disagree that it’s a strongly unpleasant odor

https://en.wikipedia.org/wiki/Thioglycolic_acid

there speaks someone who has never worked with it in large quantities, or has been in the same building as a two-ton batch of perm in the process of being mixed

[Bill_Toge]

+1 for cocoa butter, it’s terrible for forming crystalline phases during cooldown

[Bill_Toge]

the material commonly called “propanediol” is 1,3-propanediol, while the material commonly called “propylene glycol” is 1,2-propanediol

in chemical terms they are almost identical, the only substantial difference being their densities and boiling points, but DuPont have patented a sugarcane-based method for manufacturing 1,3-propanediol which wins it some points with the ‘green’ crowd

[Bill_Toge]

in my experience high-viscosity grades of HPMC work exceptionally well, especially with sulphate-free shampoos ones

[Bill_Toge]

@Gunther also if memory serves, the last SCCS review highlighted the fact that (some) parabens only acted as endocrine disruptors when injected directly into the bloodstream, and there was no evidence whatsoever that they would behave this way if they were ingested or applied to the skin

[Bill_Toge]

a good cosmetic chemist is half scientist and half engineer, with a dash of creativity and imagination - besides technical skill, the key personal qualities required to achieve this are patience, hard work, deductive reasoning and attention to detail

in the UK at least, the only practical skill a chemistry degree teaches you is how to get a chemistry degree, which is handy if you want to get a Ph.D or teach chemistry, but of limited use if you want to do anything else

[Bill_Toge]

further to @MarkBroussard‘s point, in Europe benzoyl peroxide is restricted to medicines, and resorcinol is restricted to hair dyes

encapsulated retinol is a proven, effective, safe and chemically stable way to fight acne; if you can source a water-soluble encapsulated form, even better

[Bill_Toge]

get them as cool as practically possible before filling them into containers, and put the caps on them straight away; this ensures any water loss (which causes the hard layer) is kept to a minimum

[Bill_Toge]

Agate said:

On a different note, wouldn’t it be the right thing by most countries’ regulations to list Potassium cocoate and Glycerin as the product of the chemical reaction rather than Potassium hydroxide and Coconut oil as the ingredients used initially?

you could do that, but a) most producers wouldn’t know how much of each substance is produced, unless they have an advanced chromatographic method to hand; b) there’d be some variation from batch to batch

listing the starting materials is a perfectably acceptable practise, and more accurate - after all, if the product has been produced properly, you can state exactly how much of each material has gone into it

[Bill_Toge]

how fresh is the MEA you’re using?

in my experience it starts colourless, then turns yellow and eventually orange

[Bill_Toge]

it probably is a cellulose derivative that hasn’t been declared on the label

[Bill_Toge]

get rid of PEG-150 distearate and use a high-viscosity grade of hydroxypropyl methylcellulose (Methocel) instead; in addition to the the thickening effect, it also boosts the foaming of surfactant-based products

[Bill_Toge]

the terms “cream”, “lotion” and “milk” describe how the viscosity of the product varies with shear rate, e.g. when it’s applied to the skin, or pumped; they are not scientifically rigorous, or well-defined

generally speaking:

* milks decrease to water thinness with any applied shear

* lotions are more viscous with applied shear, but are still relatively thin

* creams remain relatively thick with applied shear

the viscosity/shear relationship of a given product depends on itsemulsification system, and any rheology modifiers and surface-active waxes (C16-18 alcohols and fatty acids) that are present; as relatively small changes in these parameters can produce large changes in the viscosity/shear function, it is not directly related to the water content

[Bill_Toge]

it depends what you’re making: if you’re making viscous surfactant-based products where the viscosity of each batch is variable and can be controlled (e.g. shower gel, SLES-based shampoo), then it’s an essential piece of kit

without it, your only form of QC is subjective perception, i.e. the fate of each batch passes hinges on someone saying ‘it feels watery’ or ‘it feels too thick to me’, where the standard depends in part on which side of bed your arbiter of fate got out of that morning, and you end up spending hours or days chasing shadows

with other types of product where you have less control over the final viscosity, e.g. water-thin liquids or creams, a qualitative comparison between batches works well as an initial check, but it doesn’t hurt to use a viscometer to quantify the final result

[Bill_Toge]

get your clay sterilised, preferably by irradiation - it’s the most likely vector for contamination and if it’s clean to start with, your microbial count will be much lower

(also, minor pedantry: 30,000 = 3 x 10^4, not 3 x 10^3)

[Bill_Toge]

the contract manufacturers I used to work for never did

however, we routinely took a TVC on every production run to check the product wasn’t getting contaminated in the process of being filled