Polyurethane resin-forming composition, module membrane seal material using a hollow-shaped or flat membrane-shaped fiber separation membrane using said forming composition, and allophanate group-containing polyisocyanate composition derived from mdi and production method therefor

A polyisocyanate composition with an allophanate group, which is a reaction product between diphenylmethane diisocyanate and an alcohol, wherein a molar ratio of the allophanate group and an isocyanurate group is 80:20 to 100:0, and the composition comprises at least one selected from the group consisting of a carboxylic acid amide, a sulfonic acid amide and an active methylene compound represented by formula (2) and a tertiary amine catalyst as allophanatization reaction aids, and contains no metal catalyst,

• wherein R2 is selected from H, an alkyl group, an alkenyl group, a cycloalkyl group, an arylalkyl group and an aryl group;
• R3 and R4 are each independently selected from an OH group, an alkyl group, an alkenyl group, a cycloalkyl group, an arylalkyl group, an aryl group, an oxyalkyl group, an oxyalkenyl group, an oxycycloalkyl group, an oxyarylalkyl group and an oxyaryl group.