US Patent No. 11,779,525 B2 (Huailing Gao, Zhao Pan, Lin Wang, Shuhong Yu, Shuqi Zhu); Conopco, Inc. (doing business as Unilever), Englewood Cliffs, NJ, has patented a method of preparing composite particles comprising a non-porous spherical particulate inorganic material deposited on a plate-like inorganic material. The refractive index the said particulate inorganic material is greater than that of the plate-like inorganic particulate material. The spherical material occupies 20 to 80% of total surface area of the plate-like material and the amount of the spherical material accounts for 2-20 wt% of said composite particles.

The plate-like inorganic material is mica and the non-porous spherical particulate inorganic material is silicon dioxide.

The method entails steps of:

•  silanization of the plate-like inorganic material to get a silanized material having functional groups A;
•  silanization of the non-porous spherical particulate inorganic material to get a silanized material having functional groups B, where A≠B; and where  A and B are capable of reacting with each other such that by way of their reaction, the non-porous spherical particulate inorganic material deposits on the plate-like inorganic material; and
• reacting aid silanized material having functional groups A with the silanized material having functional groups B.

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