Silicone oil treatment of cosmetic powder
The application of silicone oil treatment in cosmetic powders aims to improve the spreadability of the powder on the skin and enhance its hydrophobicity, thereby significantly improving the spreadability and durability of cosmetics.

Purpose and effect of silicone oil treatment
Improve spreading:
The powder treated with silicone oil is easier to spread on the skin.
Hydrophobicity:
The treated powder has hydrophobicity, which enhances the durability of cosmetics.

Technical indicators of silicone oil treatment
Residual amount of Si-H group:
The residual Si-H groups on the surface of the treated powder should be below 0.2mL/g of treated powder, calculated based on the amount of H generated.
Water contact angle:
The water contact angle of the treated powder should be above 100°.

Varieties and parameters of silicone oil treatment
Powder Varieties:
Including inorganic pigments, metal oxides, mica, pearlescent powder, magnetic powder, silicate, etc.
Silicone oil parameters:
Methyl hydrogen silicone oil should meet specific chemical structure parameters.

Silicone oil treatment process
Step 1:
The methyl hydrogen silicone oil is contacted with the powder in the form of vapor, liquid or solution.
Step 2:
Heat the powder mixed with silicone oil at 270-400℃ for 2-3 hours.

Example analysis
Example 1: Using a solution of 1.5% methyl hydrogen silicone oil and hexane, mixing in a Scher mixer, drying and heat treating at 400°C for 3 hours, a silicone oil-treated sericite powder was prepared. The measured H generation amount was 0.08 mL/g, and the water contact angle was 115°.
Example 2: 500g of titanium dioxide and 35g of tetramethylcyclotetrasiloxane were placed in a desiccator at 50℃ for 1 day, and then heat treated in a 300℃ tunnel furnace for 10 minutes to obtain a silicone oil-treated powder. The measured H generation amount was 0.19 mL/g, and the water contact angle was 123°.