[RDchemist15]

If even at that level of surfactants the carbomer is effective, why not just increase the level of carbomer then? If it isn’t effective then I would question its inclusion and switch to one that is compatible like Acrylates Copolymer.

[RDchemist15]

The project I spent the most R&D time on was duplicating the transparent Neutrogena bar soaps. For most bar soap projects being off by a percentage or two has no critical influence on final product. For this line though I can say that fractions of a percent for the key backbone ingredients affect how the bar sets and how transparent the soap crystals are (about 5 raws that all interact independently/cooperatively). Appearance and colour was also very dependent on manufacturing conditions and packaging so this project really was the ultimate case scenario for R&D at every stage in the product life.

[RDchemist15]

For the record I’m not actually advertising any of this as natural. But when a customer comes and says you can’t use X, Y, or Z (see list above) it makes the most sense to have something on hand that is the most effective and readily available. Yes, their lists are sometimes arbitrary and stupid (I’ve seen no petrolatum but mineral oil is fine) but that’s the world we work in.

[RDchemist15]

@Abdullah That’s fine with me, I’m ok with any chemical modification as long as it conforms to that list. It might be in the bottom of all preservatives but if its the most robust and best that will conform to that list, it’s what I’m looking for.

[RDchemist15]

@Abdullah Thanks! Good to know that’s the second recommendation with a Benzyl Alcohol backbone

[RDchemist15]

@Perry This isn’t for any specific product so I don’t really have a standard right now for what “natural” is. But all natural standards are in agreeance for what it is not, so that’s why that’s included. So for this purpose anything that doesn’t land in the not list can be this version of “natural”.

@PhilGeis We won’t be doing that for obvious reasons, which is why I defined the importance of “best” as its highest criteria. We have a micro lab in house for all raw material and finished goods plate test counts as well as send a sample of finished good for 3rd party USP 51 challenge testing. If your opinion is that there is no preservative system that effectively fits all that criteria, that’s great, I’d like to hear that.

@Abdullah I’m ok with all those side effects listed. I’ve worked with a lot of these blends and can account for them. And yes I am pretty much looking for a functional replacement for DMDM. Do you have a top suggestion for a cleansing preservative or a leave on preservative that fits?

[RDchemist15]

@MarkBroussard Wow, just my luck I have Ultra-1 and Ultra-3. One more sample to order.

[RDchemist15]

Hi @Pharma, yes by single I don’t necessarily mean only 1 raw material INCI, I mean 1 raw material order. For example, I have pretty much the entire Euxyl and Lincoln lines. If I absolutely needed multiple product orders, then ideally it would be (mystery product) + (sodium benzoate or potassium sorbate), as we keep those more readily stocked.

[RDchemist15]

Hi @Paprik, my advice was going to be the opposite. If you can use a water bath, do it to cool as slowly as possible, especially in the 35-50C range. Use high agitation not low and if its salt thickened (even better to not worry about the trapping air), give it a little viscosity [500-1000cps]. The added viscosity I’ve found helps the pearl develop and slows cooling.

[RDchemist15]

Sulfate surfactants are probably better but you really need a solubilizer like Polysorbate 20 or Peg-40 hydrogenated castor oil. Any reason you can’t use them?
Or just send it back to your fragrance house and tell them you need a water-soluble version of it and they can work their magic.

[RDchemist15]

Hi @Perry

Out of Behentrimonium Chloride, Dicetyldimonium Chloride, Stearamidopropyl Dimethylamine are they all functionally the same even though they are all mechanistically the same? I usually see Behentrimonium Chloride paired with one of the other two and from reading about each one it sounded like Behentrimonium Chloride was more coating/ smoothing conditioning while the other two were more for antistatic/frizz conditioning (hence thinking I could eliminate one).

Will eliminate the Guar for Polyquaternium-7 in the next round.

[RDchemist15]

@vhogiono Just be aware Styrene/Acrylates Copolymer is not equivalent in appearance or function to Acrylates Copolymer. It is not a thickening or suspension agent and doesn’t require neutralization. Styrene/Acrylates Copolymer looks like essentially white/opaque background that is probably adequate in the 0.5-1% range. It does, however, have that slight bluish tinge that can be seen at the top where its thin.

I’ve also done body washes using milk (goat not cow in my case) and it does work but be prepared to use more and as a result a combination of highly robust and effective preservatives(DMDM, isothiazolones, etc). It will also have an accompanying odour which some may or may not mind. 

[RDchemist15]

For body washes to get an opaque, white background without a milky appearance I use Opulyn 301 (INCI: Styrene/Acrylates Copolymer (and) Aqua). Water soluble, relatively cheap/easy to work with, and doesn’t require suspension aid. Some people just won’t like the name

[RDchemist15]

I was wondering that recently too and found the same information you did. That said there are still drug products being sold that are 2% salicylic acid in high pH soap preparations.

Might be some useful reading:

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1468-2494.2009.00501_2.x#:~:text=Salicylic%20acid%20at%20close%20to,only%20two%20days%20of%20application
According to this paper salicylic acid at pH 6.50 is just as exfoliating as at pH 3.12. In theory, this is
likely due to a “time release” technique; where instead of being able to absorb
the Free acid right away, the inactive form remains on the skin and turns into
absorbable free acid over time. It should be noted that this applies more to
leave-on products as a rinsed product would likely not deposit any appreciable
amount, instead being rinsed away with the soap form being used. There is no
study unfortunately I can find for high range >7 pH.

https://pubmed.ncbi.nlm.nih.gov/15725565/
Salicylic acid at ph 7 retains its keratolytic function as similar preparations at pH
3.3. While, again, not at
ph 9-10 of soap, the expected free acid levels are practically equivalent so could be
directly relatable. Important to note that these only apply to BHAs and not AHAs.

[RDchemist15]

@MarkBroussard You are correct, I have never seen an end difference between the same formula produced the two different ways.

Is there any way this could be a part of a plant’s hurdle strategy? Adding salt early to inhibit microbial growth, particularly if it could be expected that there may be a longer “delay” between metering the water and adding the preservative in production?

[RDchemist15]

@em88 Ok so you’re the second person to say that then. I have never read or heard any rationale behind this though. As I said I’ve never noticed a difference between the time it takes SLES to dissolve between salt addition before or not. Have you?

[RDchemist15]

@chemicalmatt thanks for the reply. Maybe someone was trying a version of your compounding procedure and found that they still required viscosity adjustments at the end and that unpredictability made the formula “variation” permanent? Though that doesn’t explain why the end adjustment would be so large or why multiple sources formulate this way. Glad I’m not missing a fundamental trick/knowledge.

[RDchemist15]

Curiosity bump

[RDchemist15]

Usually when I see multiple preservatives when not all would be necessary I assume that some fraction of the unnecessary ones are pulled in by the preservation requirements of individual raw materials. The INCI declaration of the raw materials may have their preservative listing required (that is insufficient to preserve the entire formula) and that may be different then the standard preservatives the contract manufacture typically uses. Usually its more identifiable by botanicals and surfactant blends. I don’t see any stand out materials that would make it so in this case but figured I’d throw the idea out there to be considered.

[RDchemist15]

I think we need to differentiate between Pearlizer and Opacifier. If you want a Pearlized product use a cold dispersible liquid pearl as described above. TiO2 to my knowledge will never Pearl a product though just provide opacity/whiteness. If Pearl is not required and you just desire an Opacifier I would recommend using (INCI: Styrene/Acrylates Copolymer) instead.
https://www.ulprospector.com/en/na/PersonalCare/Detail/2669/36510/OPULYN-302B?st=1&sl=94685269&crit=a2V5d29yZDpbU3R5cmVuZS9BY3J5bGF0ZXMgQ29wb2x5bWVyXQ%3d%3d&ss=2&k=Styrene%2fAcrylates|Copolymer&t=Styrene%2fAcrylates+Copolymer
 

[RDchemist15]

Belassi said:

It’s not uncommon for commercial pearlizer to be >40 of the final formula.
— 40% of the formula? Really?

Sorry, “40% of the cost” not “40% of the weight”. For the cheaper body washes/foam baths/(SLES/CAPB), ya a lot of the cost is pearlizer when used at 3%.

[RDchemist15]

@Belassi
Maybe I need to start looking into new pearlizers then. We use the BASF line and it is ~10x more expensive then making ourselves. It’s not uncommon for commercial pearlizer to be >40 of the final formula.

[RDchemist15]

@Pharma
Thanks, makes sense. Seeding idea is out.

[RDchemist15]

@Agate
Makes sense. But I don’t think I’d call the product dangerous so much as human’s ability to follow instructions. If the product said ensure contact time of 30s and people didn’t follow that, I’m not sure the product can be faulted. The same applies to most sanitizers I’d say. Before Covid I’d be willing to bet people use way less gel then required as they typically only rub for 5-10 seconds.
To me this just sounds like sunscreen issue. People put on way less then they should by not following directions but I can’t fault the product for that. Both seem like education issues.
Tbh before Covid I was definitely in that category for hand sanitizer, even in liquid form, as practically no package states contact time.  

[RDchemist15]

@Agate
Why would it be inappropriate and dangerous to sell as a spray? The formula doesn’t really change properties being aerosolized (if anything, could one not argue it would be advantageous as smaller droplet size increase likelyhood of penetrating harder to reach areas such as under nails?)
The only issue I could see would be something like improper contact time but that would derive from human error not following instructions as opposed to the delivery method.