Heat-stable polyimide resins

A heat-stable cured resin consisting essentially of a three-dimensional polyimide which is obtained by reacting at between about 50.degree. C and 350.degree. C at least one reactant from each of the following four groups:

• i. a bis-imide of the general formula:
• ##STR12## in which Y denotes H, CH.sub.3 or Cl, and A represents a linear or branched alkylene radical having less than 13 carbon atoms, a phenylene or cyclohexylene radical or one of the radicals of formulae:
• ##STR13## wherein n represents an integer from 1 to 3 or a divalent radical with 12 to 30 carbon atoms consisting of phenylene or cyclohexylene radicals bonded to one another by a simple valency bond or by --O--, --S--, an alkylene group with 1 to 3 carbon atoms, --CO--, --SO.sub.2 --, --NR.sub.1 --, --N.dbd.N--, --CONH--, --COO--, --P(O)R.sub.1 --, --CONH--X--NHCO--, ##STR14## wherein R.sub.1 represents a hydrogen atom, an alkyl radical with 1 to 4 carbon atoms or a phenyl or cyclohexyl radical and X represents an alkylene radical with less than 13 carbon atoms,
• ii. a polyamine of the general formula:
• R (NH.sub.2).sub.x
• in which x represents an integer from 2 to 4 denotes an organic radical of valency x and selected from the group consisting of a 3 to 5 valent benzene, methylbenzene, naphthalene, pyridine or triazine radical, a 3 to 5 valent radical consisting of phenylene radicals bonded to one another by a simple valency bond or by --O--, --S--, an alkylene group with 1 to 3 carbon atoms, --CO--, --SO.sub.2 --, NR.sub.1 --, --N.dbd.N--, --CONH--, --COO--, --P(O)R.sub.1 --, --CONH--X--NHCO--, ##STR15## wherein R.sub.1 represents a hydrogen atom, an alkyl radical with 1 to 4 carbon atoms or a phenyl or cyclohexyl radical and X represents an alkylene radical with less than 13 carbon atoms ##STR16## a linear or branched alkylene radical having less than 13 carbon atoms, a phenylene or cyclohexylene radical or one of the radicals of the formulae:
• ##STR17## wherein n represents an integer from 1 to 3 or a divalent radical with 12 to 30 carbon atoms consisting of phenylene or cyclohexylene radicals bonded to one another by a simple valency bond or by --O--, --S--, an alkylene group with 1 to 3 carbon atoms, --CO--, --SO.sub.2 --, --NR.sub.1 --, --N.dbd.N--, --CONH--, --COO--, --P(O)R.sub.1 --, --CONH--X--NHCO--, ##STR18## wherein R.sub.1 represents a hydrogen atom, an alkyl radical with 1 to 4 carbon atoms or a phenyl or cyclohexyl radical;
• iii. an alazine of the general formula:
• G -- CH .dbd. N-- N.dbd. CH -- G
• in which G represents a monovalent carbocyclic aromatic radical, and
• iv. a polymerisable monomer other than a bis-imide, containing at least one polymerisable vinyl, maleic, allyl or acrylic --CH .dbd. C<
• group, in an amount from 5 to 50% by weight based on the total weight of the reactants (i), (ii) and (iii)
• in such amounts that if N.sub.1 represents the number of mols of bis-imide employed, N.sub.2 represents the number of mols of polyamine employed and N.sub.3 represents the number of mols of alazine employed, the ratio ##EQU5## is from 1.5 to 10, x being defined as above.