Verfahren zur Herstellung von lichtbestaendigen Polyadditonsverbindungen

Copolymers are produced by copolymerizing 0.05 to 25% of 2-(21-hydroxy-phenyl)-benztriazole compounds of formula: where X is a divalent bridging member having a non-colour forming character, of R1 and R2 one R is hydrogen and the other R is hydrogen, halogen, aralkyl aryl, carbonyl, carbonylic acid ester group or a divalent radical which, with X and, possibly, the ethylene group, forms a ring, and n represents the number 1 or 2, and where the benzine nucleus A can be substituted in the 4-,5- and 6-positions by alkyl, carbonyl, carbonylic acid ester, carbonylic amide, sulphonic acid amide and alkyl sulphonyl groups or halogens and the benzene nucleus B can be substituted in the 31, 41, and 51- positions by hybocarbon groups, alkoxy groups or halogens, the grouping being found in one of the positions 4-,5-,6-,31,41 and 51 with an ethylenically unsaturated comonomer. The copolymerisation may take place in bulk, in organic solvents or principally in aqueous emulsion or suspension using as catalysts the free radical catalysts, e.g. benzoyl peroxide, alpha-alpha1-azodi-isobuturonitrile, tert-butyl peroxide, or in redox systems such as mixtures of salts of persulphuric acid and sulphurous acid or by strong irradiation. A long list of comonomers includes vinyl halides, vinyl esters of organic carboxylic acid, vinyl ketones, N-vinyl and S-vinyl compounds, vinyl substituted homocyclic or heterocyclic aromatic compounds, acrylic compounds, allyl compounds, derivatives of allylamine, 1-1-disubstituted ethylenes, 1-2-disubstituted ethylenes and di and poly-enes, particularly conjugated dienes. Films may be produced from the copolymers and are useful for packaging liquids, and preserving foodstuffs and pharmaceutical products since they are UV dense.