PROCESS FOR PRODUCING METAL OXIDE PARTICLE COATED WITH HYDROPHOBIZED SILICON OXIDE

摘要

To provide hydrophobized silicon oxide-coated metal oxide particles excellent in dispersibility in fluororesins, durability to fluorinated compounds and ultraviolet-shielding properties, and further provide a fluororesin film excellent in transparency, weather resistance and ultraviolet-shielding properties. Hydrophobized silicon oxide-coated metal oxide particles obtained by a process comprising: (a) a step of adding a silicon oxide precursor to a dispersion of metal oxide particles thereby to obtain a dispersion of silicon oxide-coated metal oxide particles, (b) a step of adding a compound represented by the formula (1) or (2) and a silicon oxide precursor to the above dispersion to carry out the primary hydrophobizing treatment,
€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒR 1 4-n Si(OR 2 ) n €ƒ€ƒ€ƒ€ƒ€ƒ(1)
€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒR 3 3 Si-NH-SiR 3 3 €ƒ€ƒ€ƒ€ƒ€ƒ(2) in the above formulae (1) and (2), R 1 is a C 1-9 alkyl group, each of R 2 and R 3 which are independent of each other, is an alkyl group, and n is an integer of from 1 to 3, then (c) a step of adding a silanol-protective agent thereto to carry out the secondary hydrophobizing treatment, and (d) a step of drying the above dispersion. Further, a fluororesin film comprising hydrophobized silicon oxide-coated metal oxide particles and a fluororesin.