Home Cosmetic Science Talk Formulating Why does the cream evaporate when in a closed jar and have humectant ?

  • Why does the cream evaporate when in a closed jar and have humectant ?

    Posted by andync on December 4, 2021 at 3:48 pm

    Hi everyone,

    I am making cream with the following formula:

    - Water: ~80%

    - Propylen Glycol: 4%

    - Aquagel 45 (Laureth-7 & C13-14 Isoparaffin & Sodium polyacrylate): 4%

    - Lanolin: 3%

    - Jojoba oil: 9%

    - Pigments: 0.2%

    - Prevasertive: 1%

    I’m packing by a jar with a screw cap. the cream contains 50% of the jar.

    When i test for stability at 40c, water droplets appear on the lid of the jar.

    What should I do to fix this problem?

    Thank you!

    Abdullah replied 2 years, 7 months ago 4 Members · 7 Replies
  • 7 Replies
  • Abdullah

    December 5, 2021 at 1:44 am

    Same problem here. I fill 100g lotion in Bottles that can get 130g. 

    I think the problem is because we are not filling the bottle or jar completely.

  • Bill_Toge

    December 7, 2021 at 7:14 pm
    water has a higher vapour pressure at 40 °C than it does at room temperature - what’s happening is that some of it is evaporating, then condensing on the inner surface of the lid, which a natural consequence of storage at higher temperatures
    on the plus side, it shows your closure seals tightly - condensation is better than having the water escape through the gap between the lid and the container, and having the product dry out
  • Abdullah

    December 8, 2021 at 6:47 am

    @Bill_Toge does this water that evaporates has all the water soluble ingredients from an emulsion including preservatives or it is just water that evaporates?

    If it is just water then doesn’t it make more problem specially in microbial contamination part because it doesn’t have preservative in it? 

    When water comes out of your product, does it matter if goes out of your packaging or it condensate on inner surface of the lid and help your product not to dry out? 
    I mean unless you mix that water back to your product that we usually don’t it doesn’t mix with your product back so doesn’t do anything for the product. 

  • ketchito

    December 8, 2021 at 12:40 pm

    @Abdullah There is always a phase dynamics when in comes to water until it reaches an equilibrium; in the case of a close system, water turns into gas until the surroundings are saturated, that’s when condensation happens. If you had an open system (like a gap between the lid and the container), then water would be constantly turning into gas, drying out the product overtime. Now, this is just the free water in your formula, different to the water within your emulsion or the bound water to your hydrophilic ingredients or polymers.  

  • Abdullah

    December 8, 2021 at 1:57 pm

    @ketchito where does free water come from?

    Do you mean that in a closed system some water will evaporate and condensate and then this process will stop and no more water will evaporate and condensate again until you open it? 

  • ketchito

    December 10, 2021 at 2:35 pm

    @Abdullah Free water is water that doesn’t form part of the emulsion itself (like the lamellar network). 

  • Abdullah

    December 10, 2021 at 4:12 pm

    @ketchito in an emulsion, is this free water only not part of emulsion or it does not have anything like preservative or polymer or other water soluble ingredients too?

    In emulsion, is there only some free water or some free oil too that is not part of emulsion? 

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