Clay mask and shrinkage

I manufacture and market a 100% all-natural bentonite clay-based mask that is very rich in essential oils, powdered herbs and has added zinc oxide, coconut and olive oil. I have no issues with mold (thanks to rosemary and tea tree oils) but am experiencing shrinkage in the plastic polypropylene (PP) 16 and 8 oz containers that are due to either heat or rough handling during shipping. I have several distributors and the problems are coming from Amazon fulfillment and another very large company that will not handle the products any differently than any others. Product is that shipped by me or other smaller distributors have had no issues. Is there something I can add to the formulation that will help the product retain its shape? The products are hydrated with apple cider vinegar, no water, but of course the ACV is a dilution. Thanks.


  • PharmaPharma Member, Pharmacist
    Use tubes ;) .
  • ngarayeva001ngarayeva001 Member
    edited August 2019
    Do you actually use a preservative or you rely on tea tree and rosemary EO? If yes, then you have more serious issue than shrinkage. You do have water in it. Apple cider vinegar is water. So unless the pH is extremely low (which I doubt because of bentonite) it’s a clay in water with plenty of other sorts bug food that isn’t properly preserved.
    ‘Very rich in essential oils’.. one of the oils is tea tree oil.. that rings a bell.
  • MicroformulationMicroformulation Member, Professional Chemist
    edited August 2019
    ^^^This. You need a preservative. Unless you have tested the product your feeling that it is safe is just a feeling. TTO is not a preservative. Rosemary is an anti-oxidant, protecting the oils from oxidation but not from bacterial growth. Microformulation Cosmetic Consulting provides Custom Formulations for both large Commercial accounts as well as smaller entrepreneurs. We can provide Naturally compliant Formulations under the NSF, NPA, Whole Foods and USDA Organic Certifications. BS.Pharm Albany College of Pharmacy, Union University.
  • This is an animal product and there are no issues with the preservation. Rosemary, as well as all the other EOs in the formulation, are well proven to be antifungal and antibacterial, as well as an antioxidant. I'd like to prevent shrinkage from handling/shipping. Any suggestions would be appreciated. 
  • PerryPerry Administrator, Professional Chemist
    It's hard to give you good answers because you haven't provided enough details. For example,

    1. What are all the ingredients in the formula? (You've given a general list but specificity matters).  
    2. Maybe you show a picture of the product?
    3. What did you find in your heat stability testing? (did you run these?)

    It's a packaging issue so the easiest thing to do is to get better, air tight packaging.

    As far as antimicrobial goes, unless you've done preservative efficacy testing, you won't know if the ingredients you are using are appropriately preserving the products. If you are relying on the ingredients you said, it's highly unlikely that your product is adequately preserved.
  • MarkBroussardMarkBroussard Member, Professional Chemist

    It sounds as though the product is simply packing down in the container during shipment/handling.  I am assuming you are using wide-mouth jars?

    Alternately, you may be getting some evaporation during storage/shipment and the issue could be the lid on the jar is not creating a tight-enough seal to prevent evaporation.

    Or, it could be both of the above.  Sounds like a packaging issue more than anything else.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details
  • Thank you both and I'm not at liberty to disclose all the ingredients. Preservation is really not an issue unless you think adding a preservative will help with the shrinkage. Other than shrinkage in shipping, there are no problems with the product and it's been out for several years. I am using wide-mouth plastic jars and when we've done 'drop tests' of the product, that's when the shrinkage happens, so I'm thinking it's more of a shipping/handling issue. I also do think the plastic jars are part of the equation, but as a farm animal product, I can't move to glass. It does not appear to be heat or evaporation related, as a lot of our product is used in areas of extreme heat and there are no issues with shrinkage. I've gotten some of the jars with shrinkage returned to me and once you push it down it pops back into shape easily. I might experiment with a different sealing system, but was hoping someone had an idea for an ingredient that would help the clay retain its shape. And if you do think adding a preservative would help the product retain its shape, I'm open to suggestions. Thanks!
  • PharmaPharma Member, Pharmacist
    What's about shipping in bubble wrap or styrofoam flakes?
    Your problem is settled bulk density versus compacted bulk density. Unless you get rid of your clay, the product will be prone to that effect ;) . Or you compact it before shipping...
  • Thank you, Pharma. Unfortunately, I cannot control, though I've tried, how some of the large distributors ship the product. The smaller distributors have had absolutely NO issues with compaction, only the very large ones. It does seem to be the nature of the clay, as our 'drop' tests indicated, just wondering if there was something I could add to help this issue. If not, our best bet is to continuously try to educate our larger distributors. Compacting it before shipping, an interesting thought would be a challenge but one I will think about. 
  • MarkBroussardMarkBroussard Member, Professional Chemist
    It sounds like compaction needs to be incorporated as part of your filling process, although that might be a bit too complicated.

    I am assuming the issue is that the client opens the container and thinks that it was short-filled ... they paid for 8oz of product and only got 6oz from the looks of the product in the jar, so it's more of a perception issue than it is a product performance issue.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details
  • That's only a small part of it. The biggest issue is customer re-orders from the large distributors. Sometimes the product arrives to the customer in perfect condition and other times it's compacted. That's when customers complain. The product is always fresh, as there is high turnover and they keep low inventories, but when it looks different people get upset. Plus some of the big ones have been storing it upside down, despite all boxes clearly marked with "UP" arrows, which further makes the product look different. We'll work on compaction. We can always drop the cases on the ground before shipping! 
  • PharmaPharma Member, Pharmacist
    Depending on which type and which quality of clay you use, compaction can be caused by different effects. Clay is a funny stuff with a set of interesting behaviour, under others shrinkage/expansion.
    Without knowing anything useful about your formula, I can only guess... One such effect might be circumvented by adding some more water/vinegar (not much!). If you're lucky, it works, if not, compaction leads to a water pond on/beside your product. Else, you could consider changing clay type/quality or adding certain salts (clay reacts to different alkali and alkaline earth metals with shrinkage or expansion, respectively) to the water/vinegar; if you're lucky (again), you can put your clay product in a constantly compacted or expanded stage.
    BTW I completely zapped that you also add powdered herbs... These can worsen the shrinkage of clay (large plant particles surrounded by small clay particles are perfect for vibrational compaction) and, more likely, worsen contamination. A common and for a loooong time neglected problem even for pharmaceuticals with clay and herbs is bacterial contamination. Pharmacists still recommend tea bags for eye compresses (that's idiocy but the believe in these is so deeply engrained in us...). You can easily have 1 million CFU in a gram of good quality clay or a single tea bag. Since clay has an extremely large surface area and good adsorption, I think it's absolutely possible that you can have several weight-% of bacteria in your clay without even noticing their presence; unlike granny's strawberry marmalade showing fungi on its surface, clay is like a kitchen sponge harbouring & hiding microbes in its cavities. If the product is for animals, in most countries it will likely be regulated as "tightly" as furniture polish... IMHO that doesn't mean you shouldn't consider proper (= cosmetic/pharmaceutical) microbial testing (do you at least heat-sterilise your clay prior to mixing?). Unless your clay mask is used as "Fattening & plumping spa treatment for pig butts" :) .
Sign In or Register to comment.