| abstract |
Provided are an aqueous resin crosslinking agent that is used in the formation of a coating film with superior solvent resistance, and a polycarbodiimide compound that can be used in said aqueous resin crosslinking agent. Specifically provided is the polycarbodiimide compound shown in formula (1). Formula (1): R1-X1-(R3-N=C=N)m-R3-[X3-R4-X3-(R3-N=C=N)n-R3]p-X2-R2 In formula (1), R1 and R2 are each independently a specific residue, R3 is a specific residue, R4 is a specific residue, the plurality of R4s are the same as or different from one another, at least one of R1, R2, and R4 is a residue resulting from excluding an isocyanate group-reactive functional group from a (meth)acrylic polymer having said functional group, X1, X2, and X3 are each independently a specific bond, m and n each represent a number from 1 to 20, and p represents a number from 0 to 20. |