摘要:
An aqueous alkaline composition comprising at least one phosphonic acid, at least one polyglycol derivative and at least one glycol. The composition can be used as either a developer or a replenisher for either positive-working or negative-working alkaline developable lithographic printing plates, including thermal plates.
摘要:
Lithographic substrate comprising (a) a dimensionally stable plate- or foil-shaped support, (b) an aluminum oxide layer provided on at least one side of the support (a), and (c) a hydrophilic layer applied onto the aluminum oxide layer comprising at least one phosphono-substituted siloxane of the general formula (I)
摘要:
A method for the refreshment and reuse of loaded developers used in lithographic printing is disclosed. A polyoxyalkylene derivative is added to a silicate-containing loaded developer. Insoluble material is separated and the alkalinity level of the resulting essentially colorless liquid adjusted to produce a refreshed developer. The refreshed developer may be used to develop additional exposed imageable elements.
摘要:
A replenisher composition developing exposed radiation-sensitive printing plate precursors for plate/developer systems in which the electrical conductivity of the developer does not decrease to the same extend as the activity of the developer decreases or even increases is disclosed. A method for developing exposed radiation-sensitive printing plates using the replenisher composition is also disclosed.
摘要:
An aqueous developer for imageable elements that contain a radiation-sensitive initiator system and at least one free radical polymerizable material is disclosed. The developer develops these plates quickly, with high throughput, but with no sludge formation in the developing process. The developer contains water, a buffer, and one or more filter dyes and/or one of more free radical inhibitors. The imageable elements are useful as printing plates.
摘要:
A method for directly imaging a lithographic printing surface using infrared radiation without the requirement of pre- or post-UV-light exposure, or heat treatment employs a printing plate which contains a support with a hydrophilic surface overcoated with an imaging layer. The imaging layer contains at least one polymer having bonded pendent groups which are hydroxy, carboxylic acid, tert-butyl-oxycarbonyl, sulfonamide, amide, nitrile, urea, or combinations thereof; as well as an infrared absorbing compound. The imaging layer may contain a second polymer which has bonded pendent groups which are 1,2-napthoquinone diazide, hydroxy, carboxylic acid, sulfonamide, hydroxymethyl amide, alkoxymethyl amide, nitrile, maleimide, urea, or combinations thereof. The imaging layer may also contain a visible absorption dye, a solubility inhibiting agent, or both. In practice, the imaging layer is imagewise exposed to infrared radiation to produce exposed image areas in the imaged layer which have transient solubility in aqueous alkaline developing solution, so that solubility is gradually lost over a period of time until the imaged areas become as insoluble as non-imaged areas. Within a short time period of the imaging exposure, the imaged layer is developed with an aqueous alkaline developing solution to form the lithographic printing surface. In this method, the infrared radiation preferably is laser radiation which is digitally controlled.
摘要:
A heat-sensitive composition, for example a coating on a lithographic printing plate, comprises a carboxylic acid derivative of a cellulosic polymer. The composition may contain a radiation absorbing compound and suitable electromagnetic radiation, preferably infra-red radiation, may be used to heat the composition imagewise. The presence of the cellulosic polymer enhances resistance to certain organic liquids.
摘要:
The present invention relates to IR-sensitive compositions containing an initiator system comprising: (a) at least one compound capable of absorbing IR light (b) at least one compound capable of producing radicals and (c) at least one polycarboxylic acid comprising an aromatic moiety substituted with a heteroatom selected from N, O and S and also at least two carboxyl groups wherein at least one of the carboxyl groups is bonded to the heteroatom via a methylene group. These compositions are inter alia extraordinarily suitable for the manufacture of printing plates.
摘要:
A thermal lithographic printing plate, which can be imaged by thermal energy typically by imagewise exposure with an infrared emitting laser, a thermal printing head, etc., is made up of a hydrophilic substrate, and a composite layer structure composed of two layer coatings. Preferably, the first layer of the composite is composed of an aqueous developable polymer mixture containing a photothermal conversion material which is contiguous to the hydrophilic substrate. The second layer of the composite is composed of one or more non-aqueous soluble polymers which are soluble or dispersible in a solvent which does not dissolve the first layer. The plate is exposed with an infrared laser or a thermal print head, and upon aqueous development of the imaged plate, the exposed portions are removed exposing hydrophilic substrate surfaces receptive to conventional aqueous fountain solutions. The unexposed portions contain the ink-receptive image areas. The second layer may also contain a photothermal conversion material. Alternatively, the composite layer may be free of photothermal conversion material when thermal imaging is carried out using a thermal printing head.
摘要:
A visible radiation sensitive composition is described which comprises a binder, one or more polymerizable compounds containing at least one polymerizable group, and one or more dyes having an absorption range in the emission range of the radiation source, characterized in that said composition comprises as an initiator an initiator system consisting of a metallocene as a photoinitiator and an onium compound as a coinitiator. The visible radiation sensitive composition shows an increased radiation sensitivity compared to the known radiation sensitive compositions and is especially suitable for recording materials such as printing plates, which can, in particular, also be exposed by means of laser radiation in the visible range.