Dispersant for suspension polymerization, method for producing dispersant for suspension polymerization, and method for producing vinyl polymer particles

A dispersant for suspension polymerization, comprising:

• a vinyl alcohol polymer having a structure represented by formula 1:
• wherein, in the formula 1, R1 represents an alkyl group having 1 to 4 carbon atoms;
• n is an integer of 1 to 10;
• and * denotes a site bonding to a part other than the structure represented by the formula 1 in the vinyl alcohol Polymer,
• wherein the dispersant comprises a powder having an average particle diameter of 100 μm or more 2,000 μm or less,
• wherein the dispersant comprises;
• particles A which have a particle diameter of 500 μm or more, and
• particles B which have a particle diameter of 220 μm or less,
• wherein a ratio (A/B) of an absorbance A of a 0.1% by mass aqueous solution of the particles A at an optical path length of 10 mm and a wavelength of 320 nm to an absorbance B of a 0.1% by mass aqueous solution of the particles B at the optical path length of 10 mm and the wavelength of 320 nm is 0.7 or more and 1.2 or less,
• wherein an average value PA of a roundness P, represented by formula 2, of 50 particles arbitrarily extracted from the particles of the dispersant which have a particle diameter of 100 μm or more and 1,000 μm or less is 0.1 or more and 0.8 or less:
• P
• =
• (
• ∑
• i
• =
• 1
• N
• r
• i
• )
• /
• NR
• 2
• wherein, in the formula 2, ri represents a radius of curvature of each corner of a particle of the 50 particles arbitrarily extracted;
• R represents a radius of a maximum inscribed circle of the particle;
• and N represents a number of corners of the particle, wherein in a case in which the number of corners of the particle is 9 or more, the radii of curvature of eight corners, in increasing order from a smallest radius of curvature, are adopted, and N is set to 8.