Eastman-kodak Company

Kodak Polychrome Graphics, Gmbh

Kodak Graphic Communications Gmbh

Sun Chemical Corporation

Udo Dwars

Harald Baumann

Christopher D Simpson

Celin M Savariar-Hauck

Hans-Joachim Timpe

Michael Flugel

Bernd Strehmel

Saija Werner

Mathias Jarek

Domenico Balbinot

Detlef Pietsch

Axel Draber

Gerhard Hauck

James Russell Matz

Hans-Horst Glatt

Akira Igarashi

Robert Walter Fuss

Eduard Kottmair

Ursula Muller

Stefanie Hansmann

Tanja Ebhardt

Socrates Peter Pappas

Ursula Müller

Oliver Piestert

Michael Mursal

Ingrid Glatt

Yuuki Torihata

Harold Baumann

Lithographic printing plates are provided by imagewise exposing negative-working lithographic printing plate precursors having one or more radiation-sensitive imageable layers, followed by contacting with a processing solution that contains up to 10 weight % of one or more compounds represented by Structure (I) shown as follows:R&#x2014;C(&#x2550;O)&#x2014;N(R)&#x2014;R&#x2003;&#x2003; (I)wherein R, R, and Rindependently represent hydrogen or a substituted or unsubstituted hydrocarbon group, or two or three of R, R, and Rare combined to form one or more cyclic rings, and the total number of carbon atoms in the Structure (I) molecule is at least 7 and up to and including 33. Both negative-working and positive-working lithographic precursors can be imaged and processed using this processing solution using one or more successive applications of the same or different processing solution. The processing solution can be derived from a corresponding processing solution concentrate that can also be used for replenishment.

Method for making lithographic printing plates

Lithographic printing plates are provided by imagewise exposing negative-working lithographic printing plate precursors having a negative-working radiation-sensitive imageable layer, followed by contacting with a processing solution that has a pH of at least 7 and up to and including 11. This processing solution also includes component (1) that is a nitrogen-containing base having an atmospheric pressure melting point of at least 40&#xb0; C.; component (2) that is a non-ionic surfactant that independently has an atmospheric pressure melting point, glass transition temperature, or pour point of at least 40&#xb0; C.; component (3) that is a hydroxy-containing solution promoter; and component (4) that is a hydrophilic surface protective compound. The method is carried out in a manner such that the exposed and processed precursor is not further treated with any liquid (such as gumming or rinsing solution) between processing and mounting onto a printing press.

Negative-working lithographic printing plate precursors have improved bakeability and good shelf life and can be imaged using either UV or infrared radiation. These precursors have a negative-working imageable layer that has a unique polymeric binder comprising a polymeric backbone and further comprising at least (a) and (b) pendant groups distributed in random order along the polymeric backbone. The (a) pendant groups are ethylenically unsaturated polymerizable groups, and the (b) pendant groups are defined by Structures (I), (II), and (III) described in the disclosure.

Negative-working lithographic printing plate precursor

A lithographic printing plate precursor comprises an imageable layer comprising a free radically polymerizable component, an initiator composition capable of generating free radicals upon exposure to imaging infrared radiation, an infrared radiation absorbing dye that is defined by Structure (I) shown in the disclosure, which dyes comprise one or more ethylenically unsaturated polymerizable groups in an organic group that is attached to the methine chain. These infrared radiation absorbing dyes exhibit a reduced tendency to crystallize in the imageable layers in the presence of tetraaryl borate counter anions and therefore provide improved shelf life.

Negative-working lithographic printing plate precursors with IR dyes

Negative-working lithographic printing plate precursor a negative-working imageable layer and an outermost water-soluble overcoat layer that is disposed directly on the negative-working imageable layer. The outermost water-soluble overcoat layer comprises: (1) one or more film-forming water-soluble polymeric binders, (2) organic wax particles, and (3) non-wax matte particles. The outermost water-soluble overcoat layer has a dry thickness (t) that is defined by the following equation (I):wherein w is the dry coverage of the outermost water-soluble overcoat layer in g/m, and r is 1 g/cm. The organic wax particles have an average largest dimension D(wax) that is less than 0.9 of t (in &#x3bc;m), and the non-wax matte particles have an average largest dimension D(matte) that defined by the following equation (II):1.5 times(matte)&#x2266;40 times(in &#x3bc;m).

Lithographic printing plate precursors and use

A lithographic printing plate precursor comprises an imagable layer comprising a free radically polymerizable component, an initiator composition capable of generating free radicals upon exposure to imaging infrared radiation, an infrared radiation absorbing dye comprising an infrared radiation absorbing cation and a counter anion, and a polymeric binder. The salt formed between the infrared radiation absorbing cation and a tetraphenyl borate has solubility in 2-methoxy propanol at 20&#xb0; C. that is greater than or equal to 3.5 g/l. The use of these infrared radiation absorbing dyes in the imagable layers provides a reduced tendency of these dyes to crystallize in the presence of tetraaryl borate counter anions.

Negative-working lithographic printing plate precursors

A negative-working lithographic printing plate precursor comprises a negative-working radiation-sensitive imageable layer and an outermost layer comprising a vinyl alcohol copolymer comprising at least one unit of each of the (a), (b), and (c) recurring units, in any order, defined in the disclosure. The (c) recurring units are present in the vinyl alcohol copolymer in an amount of at least 0.5 mol %, based on the total recurring units. These precursors can be used to prepare lithographic printing plates either on-press or off-press after imaging using near-UV, visible, or infrared radiation.

Negative-working lithographic printing plate precursors and use

Negative-working imageable elements can be imaged and processed to provide lithographic printing plates. These imageable elements are sensitive to infrared radiation but are insensitive to 'white' light and thus can be more easily handled under white light conditions. These properties are possible by incorporating a filter dye having a &#x3bb;of from about 300 to about 500 nm into the imageable layer of the imageable elements.

Negative-working imageable elements

Negative-working imageable elements such as lithographic printing plate precursors, include a free-radically polymerizable component, an initiator composition that is capable of generating free radicals sufficient to initiate polymerization of the free-radically polymerizable component upon exposure to imaging radiation in the presence of a radiation absorbing compound, a radiation absorbing compound, an aerobic free radical inhibitor, optionally a polymeric binder that is not a free radically polymerizable component, and an anaerobic free radical inhibitor. The molar ratio of the anaerobic free radical inhibitor to the aerobic free radical inhibitor is at least 1:1. This combination of inhibitors provides increased shelf life and good latent image stability particularly when the element includes a polymeric topcoat layer that functions as an oxygen barrier.

Negative-working imaging elements and methods of use

Negative-working imageable element can be used to provide lithographic printing plates. The imageable element has a suitable radiation-sensitive imageable layer and a water-soluble overcoat disposed on the imageable layer. This overcoat comprises at least one poly(vinyl alcohol) having a saponification degree of at least 90%, an alkoxylation product of an alkanol, and either a 2-sulfonato succinic acid dialkylester or an alkoxylation product of a 1,4-butanediol.

Negative-working imageable elements with overcoat

Radiation-sensitive element comprising a substrate and a radiation-sensitive coating comprising (a) at least one component selected from photoinitiators and sensitizer/coinitiator systems which absorbs radiation of a wavelength in the range of 250 to 1,200 nm; (b) at least one free-radical polymerizable oligomer A having an average molecular weight in the range of 3,500 to 9,000 determined by GPC, obtainable by reacting a triisocyanate with (i) at least one acrylic or methacrylic monomer with two free OH groups and at least one (meth)acrylic group and (ii) at least one compound comprising one OH group, at least one (meth)acrylic group and at least one poly(alkyleneoxide) chain in the molecule, wherein the (meth)acrylic monomer (i) is present in an amount of 2 to 20 mole-%, based on the total amount of (meth)acrylic compounds with OH functionality.

Photopolymer composition usable for lithographic plates

Negative-working imageable elements are prepared with radiation-sensitive imageable layers that contain surface-modified silica particles such as fumed silica particles and sol-gel silica particles, that are present in an amount of from about 1 to about 40 weight %, have an average particle size of from about 1 to about 500 nm, have surface hydroxy groups, and have a carbon content of from about 0.5 to about 15 weight % that is derived from surface hydrophobic groups having 1 to 30 carbon atoms. The presence of the surface-modified silica particles provides improved abrasion resistance, reduced tackiness, and various other desired properties.

Negative-working imageable elements with improved abrasion resistance

Radiation-sensitive element comprising (a) a substrate and (b) a radiation-sensitive coating comprising (i) at least one component selected from photoinitiators and sensitizer/coinitiator systems which absorbs radiation of a wavelength in the range of 250 to 1,200 nm; (ii) at least one oligomer A of formula (I) wherein X, Xand Xare independently selected from straight-chain or cyclic C-Calkylene and C-Carylene, a heterocyclic group, a heteroaromatic group and combinations of two or more of the above, R, Rand Rare independently selected from (II) and (III) with the proviso that (1) n=0 in at least one of the groups R, Rand R, and (2) n&#x3e;2 in at least one of the groups R, Rand R, and (3) at least one group Ris different from H in formula (III). 

Photopolymer composition suitable for lithographic printing plates

Radiation-sensitive compositions and imageable elements include a polymeric or non-polymeric component in an imageable layer, which component includes 1H-tetrazole groups. The non-polymeric components can be radically polymerizable compounds. The polymeric components can have 1H-tetrazole groups that are pendant to the backbone. The use of such components in negative- or positive-working imageable elements provides high photospeed and improved developability for providing imaged and developed elements, such as lithographic printing plates that show improved chemical resistance and run length.

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Herzberg/Harz, Germany

Udo Dwars