[Bobzchemist]

No problem, Ruben.

To get back to Mark’s original question - most body butter is just a mixture of oils and waxes. Do you absolutely have to have water in your formula? It introduces so many problems…

Next, some thoughts on reverse-engineering an emulsion - there are three or four really useful bits of information that you can obtain with minimal amounts of equipment:

Emulsion type: Is it w/o or o/w? determined by pH and dilution tests, mostly.

Solids content: Hold uncovered at 110C for two hours or until weight stops changing

Oil level: how much of residue from solids test will dissolve in a volatile solvent? 

Anyone have any others?

[Bobzchemist]

Sorry if that came out sounding wrong - what I was trying to say is that the perception of having moisturized, soft skin is just as important as having skin with a higher water content. 

The amount of atmospheric water that can actually be transported into/through the stratum corneum to affect the moisture content of the skin is minuscule. But…ingredients like humectants, gels and clathrates make the consumer feel as if her skin is being moisturized. And it’s that perception that drives sales and repeat sales. Even the best moisturizer in the world, if it does not feel moisturizing and elegant on the skin, and/or if the application of the product to the skin does not make the consumer feel good, will never be purchased a second time.

[Bobzchemist]

And wouldn’t THAT be fun…although it does make awesome instant ice cream. http://chemistry.about.com/od/demonstrationsexperiments/ht/n2icecream.htm 

[Bobzchemist]

Please also remember to make the distinction between the consumer feeling that she has moisturized skin, and her actually having moisturized skin. They are two different attributes, both equally important, but they are often achieved with different ingredient systems in the same formula.

[Bobzchemist]

@David, cooling with an ice/water bath for a lab size batch (1-5 kilos) produces a rate of cooling that can’t possibly be replicated on a production scale, except under special conditions. (Cooling individual hot-filled components through a cooling tunnel, for example.)

Cooling a production size batch (25 kilo plus) can be done with ambient air cooling, tap water cooling, or refrigerated water cooling, but none of those methods can even come close to comparing to what happens in the lab with an ice bath.

[Bobzchemist]

First of all, crash or forced cooling is mostly a lab trick - it’s almost impossible (and very expensive) to get it to work in a production environment. It does improve stability, but since you can’t make it work at sizes above 5 gallons, there’s not a lot of point to it. 

Second, crash cooling does two, maybe three things to an emulsion.

1) Keeps the droplet size small - without an extended cooling time, the emulsion droplets don’t have the time to bump into each other and coalesce. The smaller the internal phase droplets are, the more stable the emulsion is, all other things being equal.

2) Reduces the wax crystal size - fatty acids, alcohols and other waxes grow crystals slowly as the batch cools, but the crystal growth stops once the batch temperature has dropped low enough. The faster you cool down to that point, the smaller the crystals, and the thinner the batch.

[Bobzchemist]

@nasrins, asking that is like asking the difference between apples and bricks. Entirely different chemicals, very few points of comparison.

[Bobzchemist]

If there’s a “secret” ingredient in something from China, I’d bet a weeks salary that it’s secret because it is poisonous and/or toxic. If it were above-board and safe, there wouldn’t be any reason to keep it secret.

[Bobzchemist]

@ageel4uk, I don’t know anything about modern hair dyes, but I do know that at one time, hair dyes were just very slightly modified versions of commercial wool fabric dyes. I also know that wool dyes can work fairly quickly. The cosmetic industry moved away from this technology as soon as these dyes were found to be carcinogenic and/or toxic.

Given the past behavior of parts of the Chinese manufacturing industry, it wouldn’t surprise me at all to find that they are using the fast-acting wool dyes that are illegal for personal care use everywhere else in the world.

[Bobzchemist]

@nasrins,

There is no guaranteed way. But, as @Perry says, even an eight week stability test is not guaranteed. The only thing that you can do is make your best guess.

A long while back, I worked for a contract manufacturer who would sell a formula to a client based on only 3 or 4 days stability results. We would keep the samples on stability and pray - and 90% of the time, a sample that passed 3 days stability at 45C would pass 1 month stability at 45C easily. 2 months was a little less likely.

In my humble opinion, the best thing to do is be upfront about the risk - tell the customer: “we’ve tested for 3 days, and it passed. That means that there’s a 90% chance that it will be stable for at least a year, and an 80-85% chance that it will be stable for two years or more.”

[Bobzchemist]

It’s an interesting approach. Traditionally, we’ve approached this empirically/experimentally - what ingredient or ingredient combo feels nicest on the skin? What makes the skin smooth or supple? Recently, what reduces TEWL has made the list of questions.

Your question assumes that the optimum skin benefit will come from putting an excess of the skin’s natural lipid blend back onto the skin. I’m not sure that this will prove out experimentally, but I’d love to see some data about it.

[Bobzchemist]

Don’t do it. This is not a place for beginners.

[Bobzchemist]

There’s a Dow Corning silicone emulsifier that’s pretty amazing…

[Bobzchemist]

Cetearyl is just a mix of cetyl and stearyl alcohols. Neither emulsifies.

[Bobzchemist]

I have no experience at all with hair dye. @Perry?

[Bobzchemist]

@azzja, have the person you’re making this for work up a lather with regular bar soap and water, and try shaving with that. That is essentially what you’re making with neutralized stearic acid. If the soap is too irritating, try adding some hair conditioner to the mix. If that works, come back here and we’ll tell you how to formulate that into a cream.

[Bobzchemist]

@MarkBroussard, that’s a good question.

@Perry, the vegans make my life very difficult. It would be fine if they were OK with synthetic material, but no…

[Bobzchemist]

That’s exactly right, @Sarah. If you’re selling to the US, you either sell a deodorant without aluminium, or an antiperspirant with it. If you decide to sell a deodorant but also use some of the botanical antiperspirant actives, remember that you are not allowed to make any sort of perspiration-related claims at all without filing a NDA.

[Bobzchemist]

The PCPC Buyers Guide is very, very useful

[Bobzchemist]

INCI Trade Name Mixture Name    Query Help

Ingredient Name	Supplier Name
Retinyl Retinoate (INCI)	Enprani Co., Ltd.

[Bobzchemist]

Question - do people consider beeswax and related products animal-derived, vegetable derived, or neither?

[Bobzchemist]

It’s funny, though. This kind of formula is the exact opposite of everything I was taught to do when I learned how to formulate liquid foundations. Back then, our goal was to get the color in the bottle a very close match to the color applied to the skin - and folks got quite upset if the color changed more than a little bit on final application.

[Bobzchemist]

Avon has a patent or two on this - that’s the first place I’d start looking for info.

[Bobzchemist]

@milliachemist is right, you can’t use cationics in your formula at all. Either the honeyquat has got to go, or you have to change your formula drastically.

[Bobzchemist]

I did mean to make this a general post, though. @Perry, can you fix or should I just repost?