Liquid dispersion of fluoride particles and method for producing same, and optical film

A method for producing a liquid dispersion of fluoride particles, which comprises the steps of:

• reacting an aqueous sodium salt solution or an aqueous potassium salt solution with a silicofluoride or a borofluoride, thereby obtaining a slurry of fluoride particles represented by AxCFy (wherein A represents sodium or potassium, C represents silicon or boron, x is 1 or 2, and y is 4 or 6);
• subjecting the slurry of fluoride particles to solid-liquid separation, and washing the resulting solid component of fluoride particles;
• drying the washed solid component of fluoride particles;
• and
• dispersing the dried fluoride particles in an aprotic organic solvent having a relative permittivity of 5 to 40, thereby generating a liquid dispersion of fluoride particles,
• the step of generating the liquid dispersion of fluoride particles is performed by adjusting the moisture concentration [a] in the liquid dispersion relative to 100% by mass of the liquid dispersion of fluoride particles so that the moisture concentration [a] (% by mass) in the liquid dispersion of fluoride particles and the relative permittivity [b] of the aprotic organic solvent satisfy the relationship represented by the following inequality (1).
• [a]≤0.06e0.15[b] (1)