[Bax65]

@Abdullah - crystallization temperature depends on the c-chain cut of the product. Normally it is mentioned in the product specification or technical data.
The higher the C12 content the higher the crystallization temp. Common grades with a share of C14 shall be kept above 20°C.
Crystallization is reversible but product needs to be carefully heated to ~40°C while gently stirring. Local overheating needs to be avoided, because normally at temp 50°C and higher the products can start degrading and once this process started it can speeds itself up (pH decrease is a good measure for this).

Anyway, ALS can also form crystalls below 15 - 20°C and needs to be reworked in the same way as SLS.
I am not aware that powders are available. I only know of 70% pastes but they are not too easy to dilute.

But as mentioned supplieres information normally describes all this for their grades.

[Bax65]

@fazalatif - you may try the following:
A
15.0 % Ceteareth-20
20.0 % PEG-7 Glyceryl Cocoate
5.0 % Dicaprylyl Ether
B
5.0 % Propylene Glycol
add 100 % Water

C
x % Fragrance (your choice)
x % suitable preservative (
Heat A and B separately up to 85°C and mix until uniform.

When both reached the temperature add Phase B slowly into Phase A while mixing gently. Stir 10 min above 80°C.

Cool to 65°C and add C while stirring.
Stir until homogenous and fill at 60°C.

This should work.

PS: It should be no issue to add the PVP via the water phase. But first try without to prove if it’s working.

[Bax65]

If I am not mistaken in such case a SLS solution should be the better choice. Because the “gas release” is linked to the drying of the SLS.
But SLS solutions are not the easiest to deal with. You need to protect them from too cold temperatures to avoid that they start forming SLS crystals.
Because it can be a pain to get the crystals back into solution (at least in IBCs).

[Bax65]

@Tyss - correct. Try to lower your total salt content.
This will very likely result in a reduced viscosity of your formulation.
To compensate this viscosity loss you shall use another, salt free thickener - e.g. the mentioned Crothix Liquid. Alternatively you can try to increase the Cocamide DEA to 3%. This normally also helps to thicken.

Regarding the opacifier: If you can get a sample of the Euperlan PCO I would give it a try. From my experience it is giving a more homogene distribution, which is an advantage when incorporated but also in stability.

[Bax65]

@ketchito - thanks for sharing the link. Interesting information!
I have mainly experience with the mentioned Euperlan PCO and there I used it with similar electrolyte concentartions without any issue - even with benzoic acid preservation at pH 4.5 - 5.5.
But generally reducing NaCl level is a good idea.
The PEG-150 Pentaerythrityl Tetrastearate is surely a quite powerful thickener for various surfactant systems.

[Bax65]

@ketchito - the electrolyte content of this formlulation should not be critical for a Styrene Acrylates Copolymer. 
@Tyss - I can imagine that the incorporation of the opacifyer might have not been homogeneous enough.
If it shall not be dispersed evenly enough particles may stick together (conglomerates) which than behave like a bigger particle - making them more prone to separate.
Maybe you can work with a Styrene/Acrylates Copolymer (SAC) that is delivered combined with a surfactant. This makes incorporation easier and more homogeneous compared to the products which only contain the polymer.
I am only aware of Euperlan PCO as such mixture (Styrene/Acrylates Copolymer with Coco-Glucoside). But maybe there is another one in the market.

[Bax65]

@vhogiono - try looking for Euperlan PCO. It is a Styrene/Acrylates Copolymer combined with a share of surfactant making it easier to dispers. It does not require a stabilizer in a formulation and definitely gives you the milk effect. No pearlshine at all.
TiO2 is likely to separate with time - although this will take long because it has very small particle size.
MICA is as well an option. You just need to disperse it. It doesn’t need to be solved - and it also doesn’t dissolve in oil. I mean: It is basically stone… Never heard this is soluble in oil…
Anyway - in case you want to work with the mentioned Acrylates Copolymer this shall help you stabilize any kind of dispersed particles like the TiO2 and MICA.

For the Styrene/Acrylates Copolymer you don’t need stabilizer as the density of the polymer is close to that of the formulation which significantly reduces the risk of floating or settlement.

[Bax65]

@Abdullah - that’s an unavoidable issue linked to the manufacturing of the SLS granulate.
To make this easier to deal with a first pH adjustment should be done right at the beginning with only the SLS in water. Then you will have the lowest possible viscosity.
Once you have added a co-surfatant and/or any kind of thickener the foam will stay even longer.
Final pH adjustment can and probably still needs to be done when the formulation is completed.
Do you have the chance to apply vacuum and have a propeller stirrer running on top of the liquid? Idea is that the rotating propeller will destroy the rising foam when vacuum is applied.  

[Bax65]

What you describe is normal for these surfactants / surfactant mixtures.
No need to worry.

[Bax65]

chemicalmatt said:

they are allowed to use Uvasorb HEB, the best UVA absorber in commercial distribution

Please note that Iscotrizinol (alias Uvasorb HEB) is described as UVB absorber with some capacity in the UVA area.
Most effective and stable UVA absorber is DHHB (Diethylamino Hydroxybenzoyl Hexyl Benzoate, alias Uvinul A Plus) - but for a US sunscreen this - unfortunately - doesn’t matter anyway.

[Bax65]

Hi Jason,
A few things come to my mind when reading your summary.

-> It is good to premix the powder polymers with Glycerin. However, instead of adding water to this premix you need to add this premix to the water (while stirring) and allow time for swelling. This should work much better.

-> I would just add the components Polysorbate 60, Ethylhexyl Palmitate and the Ceramide-2 to the oil phase.

-> As the formulation uses two polymers to provide viscosity/structure I would significantly reduce the homogenization step. Maybe you do one trail without homogenization but with just regular stirring (which I hope you can do). Normally polymers can withstand a certain homogenization but the 10 minutes with high shear sound as if they are just too much.

If these changes do not give the desired result I would “simply” increase the Sodium Polyacrylate content. These polymers usually have a quite broad viscosity specification. Might be that when the recipe was developed a batch with a viscosity from the upper spec limit was used and you do now have one from the lower end.
That’s not to uncommon.

Hope this works out.
Axel

[Bax65]

Regulatory approved UV filters are safe to use also by pregnant women.
But you will need to check which filters are okay to use in the region where you want to bring your product to the market.

I would recommend connecting to a supplier of UV filters (or their distributor). They normally have formulation suggestions available.

General remarks about working with ZnO:
Adding 20% of ZnO alone only gives you a relatively low theoretical SPF. Maybe something around 10 to 15. In detail this also depends on the formulation type. ZnO is not giving a high SPF but its protection is almost completely in the UVA area.

Best way of incorporation depends if you use a coated or uncoated material. But generally: If you add 20% of an insoluble powder you will allways experience a significant viscosity increase in your formulation. Tou counteract you will need to rework the whole thing.

But as the sum of your ingredients adds up to almost 140 you “only” added ~15% ZnO anyway.

[Bax65]

Hi everyone,

My name is Axel and I am currently working as technical expert for a European raw material supplier. My job (and my desire) is to help our clients achieving their formulation targets based on the portfolio we are selling.

As I started working in the field of personal care applications back in 1985 I would say I have a bit of experience

I came across some quite useful hints for formulation challenges in this forum and now want to participate by helping others - if I can.

And don’t worry, it is not my intention to sell “my products” to you.