Radiation-sensitive mixture and use thereof

DETAILED DESCRIPTION We claim: 1.
A radiation-sensitive mixture which is suitable for preparing a polyimide, a polyisoindoloquinazolinedione, a polyoxazinedione, a polyquinazolinedione or a polyquinazolone and which on irradiation with actinic light undergoes solubility differentiation, conprising of (a) one or more precursors having structural elements of the general formula (I) ##STR14## where, A is --O--, --NH-- or a single bond, Q is an aromatic tetravalent radical, or a radical which contains two bivalent aromatic radicals linked by a bridging group, wherein two at a time of the valences are adjacent to each other, B.
sup.
1 is --O--, or --NR.
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4 --, B.
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2 is --NH--CO--NH--, --NH--CO--O--, --NH--CO--or a single bond, R.
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1 is a readily hydrogen-donating radical, R.
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2 is a bivalent aliphatic or aromatic radical or a single bond, R.
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3 is a bivalent aliphatic, cycloaliphatic, aromatic or heterocyclic radical which may be halogen-substituted and R.
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4 is H or straight-chain or branched alkyl which may be halogen-substituted, with the proviso that the readily hydrogen-donating radical R.
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1 is a radical selected from the group consisting of isoalkyls, aminoisoalkyls, and groups of the following general formulae: ##STR15## where n=2 or 3 and R.
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5 is alkyl, aryl, halogen-substituted alkyl or halogen- substituted aryl, (b) one or more aryl-containing carbonyl compounds which when excited by UV radiation are capable of hydrogen abstraction, and optionally (c) one or more substances selected from the group consisting of a photoinitiator, a photosensitizer, a (leuco)dye and an aliphatic ketone.
2.
A radiation-sensitive mixture as claimed in claim 1, wherein the aryl-containing carbonyl compound (b) used comprises one or more aromatic ketones from the group consisting of benzophenone, xanthone, thioxanthone, fluorenone, benzil, acenaphthenequinone, tetralone, benzylideneacetone, dibenzylideneacetophenone, benzoin, benzoin ether, benzanilide, acetophenone, propiophenone, naphthoquinone, anthraquinone, anthrone, 2-, 3- and 4-hydroxybenzophenone, benzophenone-2-carboxylic acid, benzophenone-3-carboxylicacid,benzophenone-4-carboxylic acid ,3,3',4,4'-benzophenonetetracarboxylic acid and anhydride, 3,3,'4,4'-tetra(tert -butylperoxycarbonyl)-benzophenone, 2-, 3-, and 4-phenylbenzophenone, 2-, 3- and 4-alkylbenzophenones having from 1 to 10 carbon atoms in the alkyl radical, halogenated (monoalkyl)benzophenone and 4-(trifluoromethyl)benzophenone