Blocked polyisocyanate composition and use thereof

A blocked polyisocyanate composition comprising a blocked polyisocyanate obtained from a polyisocyanate and at least one blocking agent, wherein

• the blocking agent comprises a compound represented by general formula (I) shown below, and an amount of methane tetracarbonyl structures represented by general formula (II) shown below, relative to a total molar amount within the blocked polyisocyanate of bonded structures in which the compound represented by general formula (I) is bonded to the polyisocyanate, is at least 0.5 mol % but not more than 10 mol %:
• wherein in general formula (I), R11 represents a hydroxyl group;
• an alkyl group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an amino group;
• an amino group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an alkyl group;
• an aryl group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an amino group;
• or an alkoxy group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an amino group, and in the amino group, two of the substituents may be linked together to form a ring,
• each of R12, R13 and R14 independently represents a hydrogen atom;
• a hydroxyl group;
• an alkyl group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an amino group;
• an amino group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an alkyl group;
• an aryl group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an amino group;
• or an alkoxy group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an amino group, and in the amino group, two of the substituents may be linked together to form a ring, but structures in which two or more of R12, R13 and R14 represent hydrogen atoms are excluded,
• wherein in general formula (II), R21 represents a hydroxyl group;
• an alkyl group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an amino group;
• an amino group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an alkyl group;
• an aryl group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an amino group;
• or an alkoxy group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an amino group, and in the amino group, two of the substituents may be linked together to form a ring,
• each of R22, R23 and R24 independently represents a hydrogen atom;
• a hydroxyl group;
• an alkyl group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an amino group;
• an amino group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an alkyl group;
• an aryl group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an amino group;
• or an alkoxy group which may contain at least one substituent selected from the group consisting of a hydroxyl group and an amino group, and in the amino group, two of the substituents may be linked together to form a ring, but structures in which two or more of R22, R23 and R24 represent hydrogen atoms are excluded,
• wherein a portion of, or all of, the blocked polyisocyanate comprises a structural unit derived from a hydrophilic compound,
• the hydrophilic compound comprises at least one group selected from the group consisting of nonionic hydrophilic groups and anionic hydrophilic groups, and
• an amount of the nonionic hydrophilic group relative to a solid fraction mass of the blocked polyisocyanate composition is 5.1% by mass or less.