摘要:
A negative-working lithographic printing plate precursor can be imaged with infrared radiation and processed in a single step using a single processing solution having a pH of from about 3 to 11. The precursor has a primary polymeric binder that comprises recurring units derived from one or more N-alkoxymethyl(meth)acrylamides, provided that such recurring units are present in the primary polymeric binder in an amount of at least 10% based on the total dry primary polymeric binder weight. In addition, the primary polymeric binder is present in an amount of from about 12 to about 70% based on total imageable layer dry weight. The imaged precursor can be processed off-press or on-press.
摘要:
A positive-working imageable element comprises inner and outer layers and a radiation absorbing compound such as an IR absorbing dye. The inner layer includes a first polymeric material. The ink receptive outer layer includes a second polymeric binder comprising a polymer backbone and an —X—C(=T)-NR—S(═O)2— moiety that is attached to the polymer backbone, wherein —X— is an oxy or —NR′— group, T is O or S, R and R′ are independently hydrogen, halo, or an alkyl group having 1 to 6 carbon atoms. After thermal imaging, the element can be developed using an alkaline developer. Use of the particular second polymeric binder reduces sludging in the developer. Its dissolution rate in the developer is slow enough to resist developer attack in the non-imaged areas of the outer layer but rapid enough for the second polymeric binder to be quickly loosened from imaged areas and kept suspended or dissolved for a considerable time.
摘要:
Single-layer and multilayer imageable elements have a substrate and at least one imageable layer and can be used to prepare positive-working lithographic printing plates. The imageable elements also include a radiation absorbing compound and a solvent-resistant polymer binder comprising an —N(R)—C(═X)—N(R′)—S(═O)2— moiety that is attached to the polymer backbone, wherein X is O or S, R and R′ are independently hydrogen, halo, or an alkyl group having 1 to 6 carbon atoms. This solvent-resistant polymer binder is located in the imageable layer closest to the substrate and provides improved chemical resistance.
摘要:
The present invention also includes an imageable element, comprising a substrate and a thermally imageable composition comprising a thermally sensitive polymer which exhibits an increased solubility in an aqueous developer solution upon heating. The thermally sensitive polymer includes at least one covalently bonded unit and at least one thermally reversible non-covalently bonded unit, which includes a two or more centered H-bond within each of the non-covalently bonded unit. The present invention also includes a method of producing the imaged element. The present invention still further includes a thermally imageable composition comprising comprising a thermally sensitive polymer according to the present invention and a process for preparing the thermally sensitive polymer, which is a supramolecular polymer. The process includes contacting a hydrocarbyl-substituted isocytosine and a diisocyanate to produce a mono-adduct and contacting the mono-adduct and a polyfunctional material to produce the supramolecular polymer.
摘要:
A printing plate useful in lithographic printing is prepared by the process comprising: (a) applying an alkali soluble composition comprising at least one polymer composition to a hydrophilic surface on a substrate to provide the surface face with at least one layer which is alkali soluble at a pH in the range of about 6.0 to 14.0; (b) imaging the coated substrate electrostatically with a toner composition; (c) heating the imaged substrate a first time to a temperature greater than the glass transition temperature of the toner composition; (d) contacting the imaged substrate with an aqueous alkaline solution having a pH in the range of about 6.0 to about 14.0; and (e) heating the imaged substrate a second time to a temperature greater than the glass transition temperature of the toner composition. This printing plate is capable of long runs on press with good image quality and advantageously minimizes the occurrence of undesirable background toner “specking” on press. Accordingly, the printing plate is satisfactory for demanding printing tasks such as four-color newspaper printing, financial printing and the like.
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 lithographic printing surface is prepared using a thermal lithographic printing plate which requires no chemical development to remove areas of the imaged plate. The processless thermal lithographic printing plate has a sheet substrate; a hydrophilic layer on the sheet substrate; and a thermally sensitive imaging layer on the hydrophilic layer. The hydrophilic layer contains about 30 weight % of an aluminosilicate or clay, and preferably has an exterior surface which is micro-porous. The imaging layer preferably is micro-porous. The imaging layer is exposed imagewise using infrared laser radiation to produce an imaged layer. The imaged layer is treated with a conditioner liquid to produce a lithographic printing surface. By this method, the printing plate can be digitally imaged by infrared laser radiation so that the exposed areas become ink receptive and the non-exposed areas repel ink after simple treatment with a conditioner such as an aqueous surfactant solution such as a fountain solution containing an amphoteric surfactant.
摘要:
A radiation sensitive composition containing an adduct of a diazonium resin having pendant diazonium groups, with a sulfonated acrylic copolymer having pendant sulfonate groups. The sulfonated acrylic copolymer contains an acrylic moiety and a sulfonated styryl or acrylic moiety. The copolymer may optionally contain styryl moieties. The composition is useful as a radiation sensitive layer in imaging elements for graphic arts applications and is particularly useful in preparing durable, long-wear, printing plates.
摘要:
A radiation-sensitive composition and negative-working imageable element includes a free radically polymerizable component, an initiator composition capable of generating radicals sufficient to initiate polymerization of the free radically polymerizable component upon exposure to imaging radiation, a radiation absorbing compound, and particles of a poly(urethane-acrylic) hybrid that are distributed throughout the composition forming an imageable layer in the element. Imaging can be accomplished at a wide range of wavelengths from about 150 to about 1500 nm, and development can be accomplished using an organic solvent-based developer, warm water, plate cleaner, or on-press using a combination of a lithographic printing ink and a fountain solution.
摘要:
The present invention also includes an imageable element, comprising a substrate and a thermally imageable composition comprising a thermally sensitive polymer which exhibits an increased solubility in an aqueous developer solution upon heating. The thermally sensitive polymer includes at least one covalently bonded unit and at least one thermally reversible non-covalently bonded unit, which includes a two or more centered H-bond within each of the non-covalently bonded unit. The present invention also includes a method of producing the imaged element. The present invention still further includes a thermally imageable composition comprising comprising a thermally sensitive polymer according to the present invention and a process for preparing the thermally sensitive polymer, which is a supramolecular polymer. The process includes contacting a hydrocarbyl-substituted isocytosine and a diisocyanate to produce a mono-adduct and contacting the mono-adduct and a polyfunctional material to produce the supramolecular polymer.