COMPOSITE

PURPOSE:To obtain a composite resistante to developing deformation and/or cracks caused by thermal stress, thus for use in flexible printing base, by integrating inorganic material and low-thermal expansion polyimide prepared from specific aromatic diamine and aromatic tetracarboxylic acid dianhydride. CONSTITUTION:The objective composite can be obtained by integrating, either directly or indirectly (i.e. through adhesive or binder), (A) low-thermal expansion polyimide of formula I (Ar1 is aromatic group of formula II or III; Ar2 is tetravalent aromatic group of formula IV or V; R is lower alkyl, alkoxyl, etc.; n is 0-4) prepared by reaction at relatively low temperatures in a solution containing, e.g. N-methylpyrrolidone, between an aromatic diamine such as 3,3'-dimethyl benzidine and aromatic tetracarboxylic acid such as pyromellitic acid or its derivative (pref. acid anhydride) to form a polyamic acid varnish followed by heating and (B) inorganic material such as anetal, ceramic (pref. with the surface made coarse, treated with, e.g. silane coupling agent).