| 摘要 |
864,041. Photopolymerisable elements and process for forming printing relief elements. DU PONT DE NEMOURS & CO., E. 1. June 29, 1959 [July 25, 1958], No. 22309/59. Class 98(2) The elements comprise a support, an anchor layer containing a thermally active initiator; a layer of a photopolymerisable composition comprising a polymeric binder, an ethylenically unsaturated monomer capable of forming a high polymer by photo-initiated polymerisation and an addition polymerisation initiator activatable by actinic light; and between the anchor layer and the layer of photopolymerisable composition a thin barrier layer of polymer obtained by thermal polymerisation of the ethylenically unsaturated monomer in the base of the photopolymerisable layer resulting from the contact of the latter layer with the thermally active initiator of the anchor layer. Exposure and solvent treatment of such elements produces reliefs without passage of the solvent to weaken the bond between the support and the photopolymerisable layer. In Example 1 a photopolymerisable layer or sheet is prepared by casting a solution of N-methoxymethyl polyhexamethylene adipamide as binder, glycerol dimethylacrylate as monomer, and benzoin methyl ether as photoinitiator in hot alcohol on to a glass plate provided with a peripheral dam allowing to evaporate in the dark and removing from the plate, and this is laminated to a dried layer prepared from a methyl ethyl ketone solution of a copolyester prepared from a reaction mixture of ethylene glycol, dimethyl hexahydroterephthalate, dimethyl sebacate and dimethyl terephthalate; together with triethylene glycol diacrylate, methoxyphenol and benzoyl peroxide and coated on to an "alodised" aluminium support, the "alodising" process for which is described. The laminate is pressed between platens heated to 150‹C. to produce the element, and this given a test exposure under an 1800 watt mercury arc and brushed with ethanol to leave the photopolymerised areas firmly adhering to the support. Fourteen further examples and lists of the various materials to be used, including inhibitors, antihalation agents and such like are provided. Specifications 578,079, 711,279, 711,280, 741,294, 741,441, 786,119, 825,795, 826,272, 834,337 and 854,980 are referred to. |
