[Bill_Toge]

@Belassi is that a powder or a solution?

if it’s a powder, 0.01% will be plenty - 0.1% is a bit excessive in my view

(also, my comments about spillages are more relevant to solutions)

[Bill_Toge]

further to @Belassi‘s remarks about studies, I might add that an increasing number of raw material manufacturers conduct relevant in-vivo studies these days, and share the relevant data for the explicit purpose of claim substantiation

[Bill_Toge]

which type of viscometer are you using, and what spindle and speed?

also, is the SLES you’re using a dilution (28%), and is it the same batch as the one you used in the lab?

depending on the nature of the product, the viscosity can be wildly variable with different batches of SLES

[Bill_Toge]

you only need a very, very small amount for it to be effective - it’s extremely potent

in the products where we use it, the inclusion level is 0.07%, and the material we buy in is an 0.25% solution, giving an overall active concentration of 1.75 ppm

although this is not a concern with a 10 gram sample, take particular care not to have any spillages from larger containers - because if do, you’ll actually be able to taste it for the rest of the day, and it will ruin the taste of anything you might try to eat or drink

[Bill_Toge]

what’s the final pH, and the method of manufacture?

my hunch is that it’s most likely the dimethylaminoethanol tartrate, since it’s the only amine in the formula

also, I might add that sodium silicate is classified as corrosive to the skin, and unless it’s formulated at neutral or acidic pH it is extremely problematic in terms of safety

[Bill_Toge]

@Jini it’s not legal at all - it’s their ‘clever’ approach to western regulatory requirements

besides a complete INCI list, any product sold in Europe needs to be registered on the Cosmetic Product Notification Portal, which both serves as a monitor for the market and acts as an international poisons centre; among the information required is the composition of the product, whether this is in exact percentages or in bands, and Chinese manufacturers are generally loath to provide this

so to keep the formula secret while paying lip service to the law, they often miss out key ingredients (e.g. the resin, in styling products), mislabel advanced materials as something simpler, or provide the list for a similar but unrelated product

unfortunately, they get away with it because most people other than chemists with practical experience are unlikely to spot the fiddle - most of the staff in national enforcement authorities don’t have that background, so they wouldn’t have a clue there was anything wrong

I’ve known some unethical UK manufacturers to do this as well, in order to tie the customers to their factory and prevent their rivals from reproducing the formula; again, this is wholly illegal

[Bill_Toge]

potassium hydroxide has a molecular weight of 56 g/mol, and sodium hydroxide has a molecular weight of 40 g/mol

therefore, as far as the saponification reaction is concerned, 1.4 g of KOH is equivalent to 1 g of NaOH (because 1.4 = 56 ÷ 40)

as an example: if you’d normally use 10 g of NaOH in your formula, and you want to replace it with a 1:1 mixture of NaOH and KOH, you’d need 5 g of NaOH and 7 g of KOH (7 = 5 × 1.4) 

[Bill_Toge]

@johnb they also have a habit of missing out key ingredients, or declaring a list of ingredients which doesn’t remotely match the actual product

before I became more cynical and stopped taking ingredient lists as read, I spent quite a few frustrated hours trying and failing to replicate Chinese-made products!

[Bill_Toge]

I recall someone discussing a very similar product (complete with an improperly declared INCI list) on here a few months ago; if it’s like that product, “Ammonium Salt” could mean behentrimonium or cetrimonium chloride, which would act as an emulsifier

[Bill_Toge]

whereabouts are you based?

none of the major branders in my part of the world - Unilever, P&G, Cussons, Johnson & Johnson - sell cosmetics or toiletries in sealed bottles, and it’s very unusual in the wider market as well; as far as cosmetics and toiletries are concerned, unsealed bottles are the norm

and while induction seals are robust, they are not foolproof by any means; if they’re out by 1-2 millimetres, or the rim of the bottle is not perfectly flat, or the electromagnet in the sealer is slightly misaligned or not in perfect working order, they will fail to seal properly, and end up causing more problems than they solve

[Bill_Toge]

that sounds like it’s related to the water used to make up the caustic soda solution - you did right to dispose of it

[Bill_Toge]

mostly soap and prayers, to be honest

my skin is naturally very dry, but it’s not prone to flaking or irritation, so I have no real need to moisturise

the only time I’ve regularly moisturised (and often forgot) was when I had an injury from a road traffic accident

[Bill_Toge]

is there any reason you absolutely have to have seals on your bottles?

they are generally an unbelievable pain in the backside: unless you’re legally obliged to have them I’d suggest you ditch them altogether

if you want a very tight seal, a bore-seal cap made from the same material as the bottle is your best bet

also, the image links in your posts appear to be broken (I’m using Firefox 52.0.1)

[Bill_Toge]

@Chemist77 @JulietK @Ameen thank you all!

@SVOrtega glad to help, but I think the word you were after was “newbie”

[Bill_Toge]

yes - in fact, any acid/conjugate base combination included at a sufficiently high level can act as a pH buffer

[Bill_Toge]

the fact there’s no high HLB emulsifier will be a major contributor to instability; try adding ceteareth-20 or an anionic emulsifier

[Bill_Toge]

VP/VA copolymer doesn’t generally have a K value, in my experience that’s just used for PVP; the K value is correlated to the length of the polymer, and VP/VA copolymer consists of two connected polymers with different lengths

based on the fact it’s got a very similar name to the BASF material (Luviskol VA 73W) I’m guessing the material you have is a solution in water of a copolymer which is comprised of 70% VP and 30% VA

if it’s like the BASF material, it’ll consist of 50% water and 50% copolymer by weight

the figures are the maximum levels of residual monomers, i.e. unreacted starting materials, in the final material (ppm = parts per million)

[Bill_Toge]

@Belassi Unless you’re planning to expand into barrier creams or colour cosmetics, probably not.

[Bill_Toge]

@jeremien I don’t dispute this phenomenon - in fact, I’ve often replicated it both at the bench and on the plant - but I do question certain aspects of how it’s interpreted, namely the characterisation of the initial stage as a W/O emulsion.

When carrying it out, I’ve noted two key observations:

* In reported studies, and at the bench, the water mixes readily with the oil - even without any mechanical mixing. 

(In sharp contrast, W/O macroemulsions do not form spontaneously, and generally need a lot of shear just to achieve a complete and uniform mixture.)

* When water is added the oil, it forms a milky white dispersion, which fades due to the dilution effect when it’s mixed into the oil - the oil phase slowly becomes more opaque as more water is added. 

(In contrast, when the dispersed phase is emulsified of either type, the continuous phase almost immediately turns opaque at low concentrations and the opacity does not vary with subsequent additions; the dilution effect is not observed.)

Because of these inconsistencies, and my earlier points regarding thermodynamic stability, my view is that the alleged W/O phase is actually a dispersion of an O/W emulsion in oil; the oil phase remains continuous at low concentrations because the droplets of the emulsion are too finely dispersed and distant from each other to form a continuous phase. 

(N.B. This is not a double emulsion, as the O/W phase is not emulsified into the oil.)

The inversion occurs when the dispersed emulsion reaches a high enough concentration for the individual droplets to coalesce, form a continuous phase and absorb the remaining oil.  This generally results in a sudden increase in viscosity, which generates enough shear force to produce very fine, homogenous droplets.

So while in practise, the continuous phases do invert at a well-defined ratio, the fundamental structure of the emulsion is the same at all phase ratios - the variable element is how it is dispersed.

Which leads me back to my original point: in systems where this behaviour can occur, the inversion point depends on the nature of system, and is not necessarily the point where the phases are present in a 1:1 ratio of any unit.

[Bill_Toge]

isododecane is another good one, it’s typically my go-to option for anhydrous products where a dry finish is required

[Bill_Toge]

@Bobzchemist it could also mean petrolatum, which is described as “white/yellow soft paraffin” in the British Pharmacopoeia, and more difficult to wash out

[Bill_Toge]

the K value is proportional to the length of the polymer chain, which controls how brittle/tacky the film is; it also affects the viscosity and rheology of solutions, with larger K values resulting in longer flow 

VP/VA copolymer is similar to PVP but less brittle and more water-resistant (vinyl acetate being the hydrophobic part), and it has little effect on the viscosity or rheology of the finished product

the weight ratio of VP to VA is an important factor, as these polymers are available in several different ratios; this ratio affects how water resistant and how sticky the film is, with higher VP/VA ratio resulting in more tack and less water resistance

the grades typically used in water-based styling products (as opposed to aerosols) are 70% VP to 30% VA, or 60% VP to 40% VA

for information about more specialist resins, suppliers’ literature is the best place to look - BASF, Ashland and Akzo Nobel are the major manufacturers and innovators in the field

[Bill_Toge]

@Bobzchemist and light mineral oil is by far the most widely used oil in emollient creams, so it has been a causative vector in a large proportion of incidents due to its high usage level rather than any inherent hazard

but points as subtle as this are generally lost on the media and the general public

@Belassi pharmaceutical grades are not carcinogenic, though

[Bill_Toge]

@EbonygemstoneBeauty “With Private Labelling and contract filling, if I create a test formula
can you get your chosen factory to use this to fill your mass order of
units?”

this depends on whether they already have the requisite materials and packaging in stock

if they don’t, they’ll have to obtain a certain amount of these to fulfil your order, and depending on the size of your order, they’ll have to underwrite and store the remainder of the non-stock materials once your order is complete; in general, if that stock isn’t used up by the time it reaches the end of its shelf life, you’ll have to pay for it

“Can you just tell a factory straight you want a formula the same as so
and so but tweak it by adding a fragrance or oil or so called marketing
ingredients?”

this depends on whether they already have a formula matched the so and so in question; if they don’t, they’ll either have to invest R&D time (if they have a development lab within the company) or hire a consultant (if they don’t), and whether or not they choose to do so will depend on how much business you’ll potentially be giving them

[Bill_Toge]

also, that list of ingredients perfectly highlights the considerable legal and scientific grey area/minefield around the definition of ‘natural’

I’m not one for gambling, but I’d bet actual money that glyceryl rosinate, triisostearyl citrate and hydrogenated vegetable oil are not found in nature, even though they’re manufactured from materials which are (if you don’t count the catalyst used for hydrogenation)