| 摘要 |
1,135,280. Photopolymerizable compositions. E. I. DU PONT DE NEMOURS & CO. 2 June, 1966 [3 June, 1965; 4 March, 1966], No. 24695/66. Heading C3P. [Also in Division G2] Photopolymerizable compositions comprise (1) at least one addition polymerizable non- gaseous ethylenically unsaturated compound, (2) a 2,4,5-triphenylimidazolyl dimer consisting of two lophine radicals bound together by a single covalent N-N bond, and in which one or more of the phenyl groups may be substituted, and (3) at least one compound which, on reaction with the free radicals produced on exposure of component (2) to actinic radiation, produces free radicals capable of initiating the addition polymerization of component (1). The compositions may also contain (a) an energytransfer dye which enables the component (2) to be sensitive to radiation wavelengths outside the U.V. range, e.g. in the visible region, and (b) an oxygen scavenger component, e.g. S-allylthiourea, N-allylthiourea, dimethyl sulphoxide or stannous chloride, which reduces the concentration of free, dissolved oxygen in the compositions. The components of the composition may be uniformly distributed in a film-forming binding agent, e.g. a cellulose derivative or a synthetic resin. Polymerizable components (1) specified include pentaerythritol triacrylate, polyethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol dimethacrylate, polyoxyethylated trimethylol propane triacrylate, polytetramethylene glycol diacrylate, and also the cross-linkable polymers described in Specification 1,110,050. Component (3) may be an amine, e.g. a tertiary amine, an amine-substituted leuco dye, a leuco triphenylamine dye or a salt thereof, carbon tetrabromide, bromoform, N-phenylglycine, 6-bromopiperonal, ascorbic acid, 2-allyl thiourea, thiourea, sarcosine, N,N-dimethyl- or N,N-diethyl-glycine, or a sodium salt of EDTA. The compositions may also contain other components, e.g. polymerization inhibitors, dyes, pigments, thermographic compounds and colour-forming components. The compositions are polymerized on a support material to produce image-bearing elements (see Division G2).
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