Polyisocyanate coating compositions cross-linkable into enhanced anti-shock coatings

A coating composition cross-linkable into a hard/resilient and shock-resistant coating, comprising:

• a) at least one polyisocyanate which comprises at least one dimer structural unit (pattern) and at least one other polyisocyanate which is the same as or different from the above at least one polyisocyanate and which comprises at least one iminotriazinedione (imino-trimer) structural unit (pattern) of formula
• b) at least one compound having at least one mobile hydrogen function selected from the group consisting of primary or secondary hydroxyl functions, phenol functions, primary and/or secondary amine functions, carboxylic functions and an SH function, and
• c) at least one aminoplastic resin which comprises at least one melamine-aldehyde resin and/or urea-aldehyde resin and/or benzoguanamine resin and/or alkoxyalkyl derivative thereof,
• wherein one and/or the other of said polyisocyanates have at least one of the following two characteristics:
• the molar ratio (isocyanate functions/imino-trimer patterns) is less than 100, prior to masking thereof, and/or
• the molar ratio (imino-trimer patterns/trimer patterns) is greater than 3.