| 摘要 |
The present invention relates to masked polyisocyanates comprising at least two, and preferably at least three, isocyanate functional groups, characterised in that they contain at least two functional groups, each of which has resulted from the reaction of a free isocyanate functional group with an atom carrying a mobile hydrogen of a compound having at least one five-membered ring containing at least one hetero atom, the said ring having at least one mesomeric form with an aromatic nature, and in that the atom by which the mobile hydrogen is attached to the ring is chosen from the chalcogens and the elements from column VB of the Periodic Classification of the Elements, as published in the supplement to the Bulletin de la Société Chimique de France, January 1966, No. 1. These products have good stability in protecting isocyanate functional groups, a low dissociation temperature and a correct hardness in the polymerised and/or crosslinked state. Application: paints, coatings. |
