Pyrimidine-based crosslinking agents

A pyrimidine-based crosslinking agent for thermally curable compositions, comprising one or more pyrimidines of the general formula I;

• wherein:
• n=0 or 1
• R1 and R2=identical or different radicals of the general formula II:
• —NH—(CX)—YR4 (II),
• wherein X is selected from the group consisting of ═O, and ═S;
• Y is selected from the group consisting of —O—, —S—, and —NH—;
• and R is selected from the group consisting of monovalent substituted or substituted C1 to C20 alkyl, C2 to C20 alkenyl, C4 to C12 cycloalkyl or cycloalkenyl, C6 to C12 aryl or C6 to C20 arylalkyl, arylalkenyl, arylcycloalkyl, arylcycloalkehyl, alkylaryl, alkenylaryl, cycloalkylaryl, cycloalkenylaryl, alkylcycloalkyl, alkylcycloalkenyl, alkenylcycloalkyl, alkenylcycloalkenyl, cycloalkylalkyl, cycloalkenylalkyl, cycloalkylalkenyl and cycloalkenylalkenyl radicals;
• R5 is selected from the group consisting of —F, —Cl, —Br, —I, —CN, —NO2, substituted or unsubstituted radical R4, substituted or unsubstituted radical —YR4;
• and
• R3 is selected from the group consisting of radical R1, radical R2, a radical of the general formulae III and a radical of the general formulae IV;
• in which the variables R1, R2, and R5 are as defined above, and the indices m and o and the variable R6 have the following definition:
• R6=alkane-, alkene-, cyclolkane- or cycloalkenediyl or -triyl radical or divalent or trivalent aromatic, aromatic-aliphatic, aromatic-cycloaliphatic, aromatic-olefinic or aromatic-cycloolefinic radical;
• m=0, 1 or 2,
• o=0 or 1;
• with the proviso that if R3=a radical of the general formula IV, the radical R1 or R2 of the general formula I may also be a hydrogen atom.