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Manufacture of Sunscreen and Tan lotions

PCC wet milling

Wahal High shear mixers are an indispensable tool in the manufacturing of sunscreen lotion and SPF cream, which are complex cosmetic products that require precise mixing to be effective and stable. The quality of a sunscreen product is directly tied to its formulation and how the ingredients are processed, and high shear mixers are uniquely suited to address these challenges

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1. Emulsion Formation

 

Most sunscreens are emulsions, meaning they are a blend of two immiscible liquids, typically an oil phase and a water phase. High shear mixers are crucial for creating a stable, long-lasting emulsion.

  • How it works: The high-speed rotation of the rotor and the close-fitting stationary stator create a high-energy zone.As the oil and water phases pass through this zone, the intense shear forces break down the liquid droplets into extremely fine, sub-micron sizes.

     

  • Result: This small droplet size and uniform distribution prevent the oil and water from separating over time, which would render the product ineffective and lead to a poor user experience. A well-emulsified sunscreen has a smooth, creamy texture that feels good on the skin.

     

2. Dispersion of Active Ingredients

 

The active ingredients that provide UV protection, such as mineral filters like zinc oxide and titanium dioxide, or chemical filters like avobenzone, must be perfectly and evenly dispersed throughout the entire product.Poor dispersion can lead to “hot spots” of protection and areas with little to no SPF, making the product ineffective.

 

  • How it works: Wahal High shear mixers use their intense action to de-agglomerate (break up clumps of) these finely powdered active ingredients. The high-speed rotor-stator action ensures that each particle is separated and distributed evenly throughout the entire emulsion.

     

  • Result: This guarantees that the product provides the promised level of sun protection (e.g., SPF 30) with every application. It also prevents the streaky white residue that can be a problem with poorly dispersed mineral sunscreens.
    • How it works: Wahal High shear mixers are highly effective at hydrating these ingredients.The powerful suction created by the mixer’s rotor pulls the powders directly into the high-shear zone, where they are immediately wetted and dispersed before they can form lumps.

       

    • Result: This leads to a smooth, lump-free product with the correct viscosity, which is essential for a good user experience and for the product to be easily filled into containers. It also ensures that expensive ingredients are used to their full potential.

       

      3. Incorporation of Thickeners and Stabilizers

       

      Sunscreen formulations often contain various thickeners, gums, and other powdered stabilizers to achieve the desired viscosity and texture. These powders can be challenging to hydrate and can form “fish eyes” or lumps if not mixed properly.

       

     

    4. Deaeration (Removal of Air Bubbles)

     

    The vigorous mixing process can sometimes introduce air into the product, which is known as aeration. Air bubbles can affect the stability, texture, and appearance of the final product.

     

    • How it works: Many Wahal high shear mixing systems for cosmetics are designed to operate under a vacuum. This is often done in a Wahal vacuum emulsifying mixer, which uses a combination of high shear mixing and a vacuum to remove any air bubbles that may have been incorporated during the mixing process.

       

    • Result: This helps to create a dense, smooth, and uniform product, ensuring a consistent texture and an accurate volume for packaging.

       

     

    5. Improved Efficiency and Consistency

     

    Wahal High shear mixers significantly reduce the time required to produce a batch of sunscreen compared to conventional mixers.

     

    • Result: This leads to increased production output, lower energy costs per batch, and a more consistent product quality from one batch to the next. The ability to produce a high-quality, stable emulsion and a perfectly dispersed product in a shorter time frame is a major advantage for any cosmetic manufacturer.