Minimum Light Cream Maker for Liquid Sunscreen Cream (Addressing Separation/Settling)

Calculation of Light Cream Maker Quantity for Liquid Cream

For a liquid cream formula without electrolytes, where you want to use the minimum amount of Light Cream Maker to achieve a texture that may separate slightly but can be re-emulsified by shaking, determining the exact quantity without practical testing is difficult. The effectiveness of an emulsifier depends on various factors in the formula. However, based on the information and shared experiences, here are some initial recommendations for starting your trials.

Generally, Light Cream Maker is an Oil-in-Water emulsifier that works without heat and can handle up to 20% oil in a formula (if the oil content is higher, you might need to consider using other emulsifiers in combination, such as Milk Lotion Maker, which requires heat). Light Cream Maker can tolerate some electrolytes, but high amounts of electrolytes will thin the cream and require more emulsifier to increase viscosity.

In the case of your formula, which contains no electrolytes and accepts separation that can be re-emulsified by shaking before use, you can use Light Cream Maker in a lower-than-usual percentage. Based on shared experiences, starting your trials with approximately 0.3% to 0.5% of Light Cream Maker is a good starting point. A concentration of 0.5% might prevent separation entirely, while 0.3% might result in a very liquid texture with slight separation that requires shaking before use, which aligns with your requirement.

First Formula

• OMC 10%
• Octocrylene 10%
• Octisalate 5%
• VitE 0.1%
• Disodium EDTA 0.1%
• Phenoxyethanol 0.5%
• Water + Light Cream Maker (remaining)

In this formula, the liquid oil phase (OMC, Octocrylene, Octisalate, VitE) totals 10% + 10% + 5% + 0.1% = 25.1%.

For creating a liquid cream that accepts separation and can be shaken before use, based on the shared experiences, starting your Light Cream Maker trials at approximately 0.3% to 0.5% is a reasonable range. 0.5% was suggested to prevent separation, while 0.3% was reported to work well for a liquid texture. You can start at 0.3% and see if it provides sufficient emulsification with shaking, or try 0.5% if you prefer less initial separation.

Second Formula

• Zinc Oxides Micronized 10%
• Lipidsoft 20%
• OMC 10%
• Octocrylene 10%
• Octisalate 5%
• VitE 0.1%
• Disodium EDTA 0.1%
• Phenoxyethanol 0.5%
• Water + Light Cream Maker (remaining)

In this formula, the calculation of the oil phase for the emulsifier considers the liquid components. Micronized Zinc Oxide is a solid powder and is not included as part of the liquid oil phase for the purpose of calculating the amount needed for emulsification.

The liquid oil/ester phase in this formula consists of:

• Lipidsoft 20%
• OMC 10%
• Octocrylene 10%
• Octisalate 5%
• VitE 0.1%
• Total Liquid Oil/Ester Phase = 20% + 10% + 10% + 5% + 0.1% = 45.1%

This formula has a higher liquid oil/ester phase (45.1%) than the first one. However, the primary challenge with this formula in a very liquid texture is not necessarily the oil/water separation (emulsification) but the settling (sedimentation) of the solid Zinc Oxide particles. This is a normal occurrence for physical sunscreens in thin liquids that are not viscous enough to suspend the particles. This settling is different from oil and water separating.

For emulsifying the liquid oil phase (45.1%) in this formula while aiming for a very liquid texture and accepting the settling of zinc oxide, you can still start your Light Cream Maker trials in a similar low range, perhaps 0.3% to 0.5%. This amount should be sufficient to emulsify the liquid oils and prevent oil/water separation. However, you should expect the zinc oxide to settle at the bottom when the product is left standing. Shaking before use will be necessary to re-disperse the zinc oxide, which aligns with your acceptable criteria. Significantly increasing the Light Cream Maker to prevent zinc oxide settling would result in a much thicker cream, which is not your goal.

In summary, for both formulas, starting your trials with Light Cream Maker at around 0.3% to 0.5% is a practical approach to achieve a very liquid texture with sufficient emulsification, accepting that solid particles like zinc oxide will settle in the second formula and require shaking. The exact minimum will need to be determined through your own testing.