| abstract |
PROBLEM TO BE SOLVED: To provide a primer for a porous substrate, which prevents air pollution, improves workability, and has a sufficient impregnation property without using an organic solvent, and a primer for a porous substrate. Provide a processing method. An allophanate-modified polyisocyanate synthesized from an aliphatic diisocyanate, substantially free of an organic solvent and an organic diisocyanate. The problem is solved by a primer for a porous substrate having a viscosity at 5 ° C. of 500 mPa · s or less. Preferably, the primer further contains an isocyanurate-modified polyisocyanate of an aliphatic diisocyanate. |