| 摘要 |
1,231,822. Light-sensitive oxetane polymers. FARBWERKE HOECHST A.G. 8 July, 1968 [6 July, 1967], No. 32433/68. Heading C3R. Polyethers which can be cross-linked by light are prepared by polymerizing oxetanes of the formula in which R 1 represents the radical where x is 1 or 2, a benzoyl-benzoyloxy radical, he radical or the radical wherein m is 0 or 1, n is 0 to 4, R 3 is a carbocyclic or heterocyclic aromatic group or when m and n are both zero may be H or CH 3 , R 4 is H, alkyl, alkoxy or halogen, R 5 is Cl or phenyl and R 2 has the same meaning as R 1 or is H, alkyl, alkoxy, aryloxy or halogen. They may be polymerized alone or together with a lightinsensitive oxirane, oxetane or oxolane, and a cationic catalyst is used. Examples of comonomers are propylene and styrene oxides, tetrahydrofuran, 1,4-epoxycyclohexane and 3,3- bis(chloro-, iodo-, cyano- and acetoxy-methyl) oxetanes. Suitable catalysts are BF 3 -etherate, phosphorus pentafluoride and trialkyl-oxonium salts. Epichlorhydrin may be added as initiator. The polymers have molecular weights of about 1500 to 6000. Before cross-linking, the polymers are soluble in a variety of solvents from which films and coatings can be obtained which are rendered insoluble by light.
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