The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 07, 1992
Filed:
Mar. 02, 1990
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
The present invention relates to copolyimides of 100-70 mol % of recurring structural units of the formula I and 0-30 mol % of recurring structural units of the formula II ##STR1## in which z.sup.a is a tetravalent aromatic tetracarboxylic acid radical other than that of thioxanthonetetracarboxylic acid, the carboxyl groups thereof in each case being located in pairs in the ortho-position or peri-position relative to one another, and x.sup.a is a divalent aromatic diamine radical which, in at least one ortho-position relative to at least one nitrogen atom, carries a hydrocarbon substituent having at least one aliphatic .alpha.-hydrogen atom or x.sup.a is a radical of the formula III ##STR2## in which X.sup.c is a divalent aromatic diamine radical which, in ortho-position relative to both nitrogen atoms, carries in each case at least one mono-valent hydrocarbon substituent having at least one aliphatic .alpha.-hydrogen atom, n assumes an average value of 1.0 to 2.5, Z.sup.b is as defined for Z.sup.a and X.sup.b is an aliphatic, cycloaliphatic, aromatic or araliphatic diamine radical, excluding a radical of the formula III, with the proviso that the proportion of radicals of the formula III in the formula I is selected such that the quantity of thioxanthonetetracarboxylic acid radicals, relative to the total quantity of tetracarboxylic acid units in the copolyimide, is between 1 and 30 mol %. These copolyimides have a high radiation-sensitivity and can be combined with structurally related polyimides to form photocrosslinkable compositions which can be employed for coating purposes.