Verfahren zur Herstellung von hochmolekularen Polyamid-imiden

1,268,057. Coating. FARBENFABRIKEN BAYER A.G. 11 March, 1969 [13 April, 1968], No. 12629/69. Heading B2E. [Also in Division C3] Polyamide-imides are produced by reacting at -20 to 450‹C (i) a isocyanate R 1 -(NCO) n or a specified equivalent reactant, (ii) an anhydride and (iii) a lactam In these formulµ the Rs are optionally substituted hydrocarbon radicals or in the case of R 5 and R 6 may also be H; x is 2 to 20; n is 2 to 6; y and z are each 1, 2 or 3; and X is -NCO, -NR 1 .COOR 5 or -NR 5 -CO-NR 5 -R 5 in (i) and a monocarboxylic ester or dicarboxylic anhydride group in (ii). Reactant (i) may be replaced by the corresponding isothiocyanate, lactam adduct or blocked isocyanate (defined as embracing the urea and carbamic acid alkyl ester derivatives) as the specified equivalent compound. Numerous reactants (i), (ii) or (iii) and organic solvents and catalysts for the reaction are specified. Other polyfunctional reactants may be included in the reaction, e.g. diamines, acid-terminated polyesters or polyethers, diols, triols, aminoalkanols or polycarboxylic acids. In Examples (i) is diphenyl methane-, tolylene-, or hexamethylenediisocyanate or a phosgenated aniline-formaldehyde condensate; (ii) is trimellitic or azo-4, 4/-bisphthalic anhydride and (ii) is capro- or dodecano-lactam. In Ex. 6 glycol is also a reactant. The products are heat resistant plastics useful for lacquers, films and shaped articles. Additives such as fillers, pigments and polyesters may be added to the polymers. Coatings. The products of the Examples are applied to glass or metal and stoved for 20 minutes at 200‹C and 20 minutes at 300‹C. Blends of the polymers with polyesters are said to be useful as wire enamels and in Ex. 2 the coating solution is a blend with a polyester of terephthalic acid, glycol and glycerol.