Polyimide

Abstract

This invention relates to a novel fluorine-containing polyimide or polyimide copolymer being colorless and having transparency and very low dielectric characteristics, and has a novel aromatic diamino compound used for the polyimide, a preparation process thereof, a polyimide-based resin composition comprising the polyimide or polyimide copolymer and a fibrous reinforcement, a process for preparing the resin composition, an injection molded article of the resin composition. The polyimide comprise a requisite structural unit having one or more recurring structural units of the formula: ##STR1## wherein Ar is a tetravalent radical having 6 to 27 carbon atoms and being selected from the group consisting of a monoaromatic radical, condensed polyaromatic radical and noncondensed polyaromatic radical having aromatic radicals connected to each other with a direct bond or a bridge member, a trifluoromethyl radical is situated at the 3- or the 4-position on a pyridine nucleus, and an imide nitrogen atom is connected at the 3- or the 4-position to an ether bond. The polyimide or polyimide copolymer has excellent heat resistance, outstanding melt-flow stability and greatly improved processability, and also is colorless and has high transparency and very low dielectric coefficient, and can be expected to be used as raw materials for electric.cndot.electronic appliances and optical instruments due to the above characteristics.