Polyvinyl alcohol-based resin, method for producing polyvinyl alcohol-based resin, dispersant and dispersant for suspension polymerization

A polyvinyl alcohol-based resin, wherein

• a volume average degree of saponification is 68 mol % to 85 mol %, and
• a ¼ value width of a degree of saponification distribution obtained by high performance liquid chromatogram measured is 7.0 minutes or less under the following conditions:
• apparatus:
• liquid chromatography,
• detector:
• corona charged aerosol detector,
• column:
• particle diameter:
• 5 μm, 4.6 mm inner diameter×250 mm length,
• mobile phase flow rate:
• 0.5 mL/min,
• injection amount:
• 50 μL, eluent:
• solvent A ultrapure water, solvent B tetrahydrofuran,
• high-pressure gradient:
• solvent A/solvent B volume ratio=90/10 at 0 minutes, 90/10 at 5 minutes, 14/86 at 43 minutes, and 14/86 at 58 minutes by a gradient elution method,
• measurement temperature:
• 50° C.,
• sample:
• 10 vol % tetrahydrofuran aqueous solution at concentration:
• 2 mg/mL, and
• data acquisition interval:
• every second.