1,154,514. Glass cloth laminates. INSTITUT FRANCAIS DU PETROLE DES CARBURANTS ET LUBRIFIANTS. 4 May, 1967 [5 May, 1966], No. 20847/67. Heading B5N. [Also in Division C3] Laminates are prepared from polyimidazoles obtained by reacting aromatic tetraamines of formula with aromatic polyanhydrides of formula where A, B and B<SP>1</SP> are aromatic homocyclic or heterocyclic radicals which may contain single rings, condensed rings or several distinct rings linked by direct bonds or by -CH 2 -, -CO-, -C(CH 3 ) 2 -, -O-, -S-, -SO- or -SO 2 -, and n is greater than 1. The tetraamine may be reacted with the polyanhydride in a first step to obtain a resin which is dissolved in a solvent, and the solution used to impregnate glass cloth, which is then heated to evaporate the solvent and cure the resin, the laminates being made by heating under pressure layers of the impregnated glass cloth. In examples, laminates are made using resins obtained by reacting 3,3<SP>1</SP>-diaminobenzidine with isophthalic polyanhydride.