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Home Cosmetic Science Talk Formulating Best non-nano zinc oxide that doesn’t leave white residue @ 5-10%?

  • Best non-nano zinc oxide that doesn’t leave white residue @ 5-10%?

    Posted by Zink on June 28, 2016 at 1:50 am

    Looking for a “non-nano” or primary particle size is greater than 100nm, zinc oxide based raw material that can be used at around 5-10% effective zinc oxide concentration without leaving white residue on the skin. So likely as low particle size as possible without getting down to the nanoscale, and/or perhaps there are supporting ingredients that can help eliminate this problem.

    It’s intended for a daily moisturizing formula that will eventually be SPF rated. Let me know if you know any good raws.

    Zink replied 6 years, 11 months ago 7 Members · 17 Replies
  • 17 Replies
  • Microformulation

    Professional Chemist / Formulator
    June 28, 2016 at 1:43 pm

    Non-Nano ZnO >100nm with no whitening at 5-10%? Try Peter Pan Chemicals from Never Never Land.

  • Bill_Toge

    Professional Chemist / Formulator
    June 28, 2016 at 2:35 pm

    if it’s going to have an SPF rating, you’re better off with the nano type

  • Bobzchemist

    June 28, 2016 at 3:48 pm

    Are consumers really that scared by the may-be, possibly, no-actual-proof-but chemicals-scare-us crowd that there’s a significant market for non-nano Zinc Oxide sunscreen?

    Also, I don’t think a commercially viable non-nano but also non-whitening zinc oxide can be manufactured. I’m willing to be proven wrong, but I think that the extremely tight particle size control this would require would be so expensive that the Zinc Oxide would be incredibly more expensive than nano zinc oxide.

  • Microformulation

    Professional Chemist / Formulator
    June 28, 2016 at 4:12 pm

    My two cents is that much like many “Marketing trends” in many cases we place too much emphasis on what “might” be an issue and we are too willing to compromise on performance. In many cases we are placing far too much emphasis on what fringe markets may want.

    That said, in the bulk of my experience, the Natural lines want ZnO or TiO2 vice Chemical sunscreens. Honestly, in the numerous calls I have had, nano has not come up at all in the last 24 months.

  • Mike_M

    June 29, 2016 at 1:04 pm

    @bobzchemist for us the interest comes from legal not from consumers. They are pulling their hair out these days with the ridiculous consumer advocacy groups.

    @zink we use nano zinc in our lotion with SPF without any issues. In the US we do not make sunscreen so this is our only line with significant SPF.

  • Bobzchemist

    June 29, 2016 at 2:29 pm

    Your legal department needs to understand the realities of pigment processing. When you mill/grind a product, you inevitably produce particles in a range of sizes.

    In order to get a specific particle size range, you need to process the particles further, by putting them through a classifier that will reject the particles that are too large and the ones that are too small. Making sure that you have no nano particles in your Zinc Oxide isn’t too hard, as long as you don’t worry too much about how large the particles are. Making sure that your particles are just slightly larger than nano-sized to be able to say the ZnO is non-nano, but small enough to be transparent, would require 4 or 5 passes (or more) through a very precise classifier after the ZnO has been milled. 

    I’m not saying it can’t be done - I’m just saying that it would result in a Zinc Oxide that costs $200 - $300 per kilo.

    I’m also going to point out that these consumer advocacy groups are full of used food. Consumers have been using nano-sized zinc oxide on their skin for almost a century - because the milling process needed to make ZnO not feel like sandpaper has been turning out some fraction of their output in nano-sizes all along - it’s unavoidable. The technology revolution has been the ability to make ALL of the output nano-sized.

  • Belassi

    June 29, 2016 at 4:19 pm

    Great post Bob, very informative, thanks.

  • Anonymous

    June 29, 2016 at 4:22 pm

    I agree with the previous posts. All non-nano ZnO products will cause some whitening. Nano is considered <100nm and anything >200-300nm tends to cause whitening. So what you are looking for is ZnO milled to 100nm-200nm which is a very fine margin. As bobzchemist has mentioned, you can’t avoid some nano particles being in the mixture. If you find a supplier with these specification, please let us know. You can decrease the whitening side effect by choosing your emulsifiers and other ingredients very carefully to avoid opacity.

    There is ZinClear which is a nano Zinc but much of it aggregates to form ~2000nm sized particles. Although, they have gotten a lot of flack for trying to advertise their product as non-nano.

    The EWG does an extensive analysis of sunscreen properties. At the end of the page there is a list of popular ZnO suppliers and their particle size. 

  • Microformulation

    Professional Chemist / Formulator
    June 29, 2016 at 8:33 pm

    Damn, not another EWG reference!

  • Zink

    June 30, 2016 at 6:00 am

    Thanks! Maybe the non-nano demand isn’t as large as I thought, I’m personally fine with nano scale zinc oxide (it’s even FDA approved for used in food), but wondered if there were any off the shelf non-nano non-whitening options on the market, e.g. Grant has a UV-Cut ZNO 61 with a primary particle size of 255 nm that could be best of both worlds for low SPF applications?

    But won’t all ZnO be both nano and non-nano? Is it non-nano when > 50% of the ZnO is agglomerated into > 100 nm particles and nano when > 50% of the ZnO is agglomerated into < 100 nm particles?

    What I need to know now is which ZnO blends would work best for my use, ideally one in a plant based carrier but  I’m fine with coatings. Grant, Kobo, Umicore, Croda and Antari all make various blends - any experience with them or is it time to order samples?

    Then comes the consideration of UV-A protection where large particle size ZnO does a lot better than nano..

  • Microformulation

    Professional Chemist / Formulator
    June 30, 2016 at 1:04 pm

    I have had great success with the Croda Solaveil line. They do (or at least did, it has been 18 months) have a pre-dispersed Jojoba base. There are various other suppliers. These materials are easier to work with, but in the end you really need adequate mixing energy.

    I think Bob explained all your questions above. Yes, with milling it is likely that you would have a spread of particle sizes. Even with the Grant product, the average particle size is 255. This is just the peak on the bell curve.

    Take one thing to heart. With the limitations of the material, non-nano non-whitening is not feasible no matter how much you wish it to be.

    Here is my advice. First, abandon the term “natural” until such time that we have an agreed upon and legislated definition. Refine the term to “Naturally compliant” and then learn/follow a Natural standard. Then, remember a successful and elegant product that is like a three legged stool and the legs are Natural compliance, cost and performance. Make anyone leg to long (I need non-nano, Gluten free, Palm free ZnO for example) and the stool topples over. Balance is the key.

    This is especially important with sunscreens in the Market. Many I have sampled are absolute messes! In order to disperse the ZnO, give great spreadability and perhaps add water resistance, you will find that you may have to stray a bit from the standard. This is much less a factor now than it was even 5 years ago as the distributors have made many more “natural” materials available to us.

  • Zink

    June 30, 2016 at 4:56 pm

    @Microformulation I never mentioned “natural”, but thanks for sharing your thoughts ;) What sort of mixing energy are we talking about btw? 
    I want to make a formula that I will use every day for the rest of my life, so it needs to be extremely gentle, safe and good for the skin (not too good either, some formulas are best cycled) beyond protecting from UV-B and A.

    I’ll see if I can sample the Croda one, historically they like to make things overly complicated.

  • cherri

    June 30, 2016 at 4:58 pm

    @Zink applechem has non-nano zinc.

  • Bobzchemist

    June 30, 2016 at 6:14 pm

    non-nano is a marketing term, really. It’s not completely meaningless, but it’s for the most part untestable as far as distinguishing between primary particles and agglomerates are concerned, unless you are going to the trouble of using a SEM.

  • Zink

    June 30, 2016 at 6:32 pm

    @Bobzchemist makes sense, what you can do I guess is inform your customers about the science which seems to rather conclusively say that nanoscale zinc oxide particles are fine. Do you btw have any zinc oxide pigment blend recommendations?

  • Microformulation

    Professional Chemist / Formulator
    June 30, 2016 at 7:35 pm

    I have used the Applechem Zinc. It does still whiten.

  • Zink

    June 30, 2016 at 8:33 pm

    Looking for nano zinc blends ;)