DE60200096T2 - Lithographic printing plate with coating and development taking place on the printing press - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a lithographic printing process in which an imaging material unwound from a supply roll to a drum of a printing press wrapped, exposed imagewise and is developed by supplying single fluid ink.

GENERAL STATE OF THE ART

For lithographic printing machines you use a so-called print master like one on a drum printing plate clamped on the printing press. The master surface carries a lithographic Image and a print is obtained by first printing ink on the image applied and then transfer the color from the master to a receiving material, usually paper becomes. With conventional Lithographic printing becomes both ink and fountain solution water based on the lithographic image made from oleophilic (or hydrophobic, i.e. ink-attracting, water-repellent) Areas and hydrophilic (or oleophobic, i.e. water-attracting, ink-repelling) Areas is built, attached. With so-called driographic In printing, the lithographic image consists of color-attracting and color-abhesive (i.e. ink-repelling) Areas and will during of driographic printing only ink is applied to the master.

Print masters are usually post the so-called computer-to-film process get where different prepresses like choosing the font, Scanning, producing color separations, grid, trapping, layout and imposition digitally and each color separation via an imagesetter on a graphic Film is exposed. After development, the film can be used as a mask for the Exposure of an imaging material, as a printing plate precursor designated, used and after the development of the printing plate a printing plate is obtained which can be used as a master.

In recent years, the so-called Computer-to-plate method (CTP process) has become significantly more important. at this process, also as direct digital printing plate imaging (Direct-to-plate process) is referred to the manufacture of a film because the digital document is about a so-called platesetters transferred directly to a printing plate prepress becomes. In the case of a special type of CTP method, one is opened a plate drum of a printing press clamped printing plate precursor over a imagesetter built into the press exposed. This method can be referred to as a "computer-to-press" process and printing presses with built-in imagesetter are sometimes Called digital presses. An overview of digital presses can be found in "Proceedings of the Imaging Science & Technology's 1997 International Conference on Digital Printing Technologies (Non-Impact Printing 13) ". Computerto-Press process are described in e.g. B. EP-A 770 495, EP-A 770 496, WO 94001280, EP-A 580 394 and EP-A 774 364. EP-A 640 478 describes a digital one Printing press with one automatic, one feed roller and one inside the plate roller system of the plate drum described.

Typical plate materials used in computer-to-press processes are based on ablation. A problem associated with ablative plates is the production of waste that is difficult to remove and can interfere with the printing process or contaminate the exposure optics of the built-in imagesetter. Other processes require wet processing with chemicals that can contaminate the electronic components and optics of the integrated imagesetter and other press equipment. Therefore, lithographic coatings that do not require wet processing or that can be developed with tap water, printing ink or fountain solution are particularly desirable in computer-to-press processes. Such plates are described in WO 90002044, WO 91008108 and EP-A 580 394, but they are all ablative plates with a multilayer structure, which makes them less suitable for on-press coating. In US 6,095,048 discloses the development of an ablative material with a single fluid ink.

A non-ablative, with fountain solution and ink developable plate is described in EP-B 770 494. This patent discloses a method in which a Imaging material having an imaging layer which is a hydrophilic binder, a compound that is able to convert light into heat, and contains hydrophobic thermoplastic polymer particles, imagewise exposed is, the exposed areas in a hydrophobic phase, the forms the printing areas of the printing master, converted become. The print cycle on the press can start immediately after exposure without additional Processing started because the layer is interacting with the fountain solution and the printing ink that are used during the printing process Drum fed be developed. In this way the chemical wet development of these materials "hidden" from the user and during the first runs the printing press.

With the latter method, the problem is connected that the On-press development included as steps that the Pressure plate first Fountain water and then also supplied printing ink becomes what is easily executable is in printing presses where the inking rollers and dampening rollers independently can be operated from each other. Optimal on-press development becomes more difficult to achieve, however Fountain solution and ink can be applied at the same time, which the the only option is for printing presses with an integrated printing ink / fountain solution supply system.

In addition, the development of plate materials with fountain solution not possible with driographic printing presses This is because only printing ink is fed to the plate in such presses. In that no cooling effect due to the absence of water-based fountain solution there, driographic printing presses require careful temperature control.

There is therefore a need for one Process in which the on-press development of an imaging material without the supply of water-based fountain solution can be achieved.

BRIEF PRESENTATION THE PRESENT INVENTION

Object of the present invention is a lithographic printing process with automatic plate feeding and exposure on the press that is common to all lithographic printing presses, even those without a fountain solution, a development on the Press allowed to provide. In this way, a fully automatic printing process, at which the stages of plate feeding, exposure and development all are feasible without human intervention.

This task is solved by the method defined in claim 1. It has been found to be excellent Results can be achieved by using single-fluid printing ink for on-press development an imaging material with an imaging layer, the soluble is in such a single fluid ink or in the exposure step soluble in it can be made. Single fluid printing ink means usually an emulsion of an ink phase in a polar Phase or vice versa an emulsion of a polar phase in a Ink phase. Single-fluid ink allows printing with a conventional one wet lithographic print master without the use of fountain solution. The ink phase adsorbs on the hydrophobic areas of the Print master while the polar phase moistens the hydrophilic areas and thereby Adsorption of the ink component on the non-printing areas of the lithographic image prevented.

The printing process according to the invention is a how defined in claim 1, the steps (i) to (vi) more comprehensive Cycle that can be repeated several times, the precise number of length depends on the path of the imaging material on the supply reel. Preferably is the number of printing cycles more than 1, particularly preferably more than 10 and very particularly preferably more than 30. Since the replacement and loading the plate is fully automatic, the downtime the printing press is reduced to a minimum between printing cycles.

Other advantages of the present Invention will be apparent from the description below. specific Flag for preferred embodiments according to the invention are in the subclaims described.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The imaging material used in the present invention contains a flexible lithographic base and an imaging layer.

lithographic document

The lithographic base contains one carrier in the form of a sheet that is sufficient is flexible so that it can be wound on a spool. The carrier has a hydrophilic surface or is coated with a hydrophilic layer. The flexible beam can A carrier made of paper, plastic, a thin Metal such as aluminum or a composite or laminate thereof, z. B. a laminate of plastic and metal. A very a particularly preferred example is one laminated onto aluminum PET film that's enough is thin to be able to be wound on a spool. Preferred examples for plastic films are a polyethylene terephthalate film (PET film), a polyethylene naphthalate film, a cellulose acetate film, a polystyrene film, a polycarbonate film etc. The plastic film carrier can be opaque or translucent his.

A particularly preferred lithographic base with a hydrophilic surface is an electrochemically grained and anodized aluminum support. The anodized aluminum support can be processed to improve the hydrophilic properties of the support surface. For example, the aluminum carrier can be increased by processing the carrier surface with a sodium silicate solution Temperature, e.g. B. 95 ° C, silicated. As an alternative, phosphate processing can be carried out, the aluminum oxide surface being processed with a phosphate solution optionally also containing an inorganic fluoride. Furthermore, the aluminum oxide surface can be rinsed with a citric acid or citrate solution. This treatment can take place at room temperature or at a slightly elevated temperature between about 30 ° C and 50 ° C. Another interesting method is to rinse the aluminum oxide surface with a bicarbonate solution. Furthermore, the aluminum oxide surface can be processed with polyvinylphosphonic acid, polyvinylmethylphosphonic acid, phosphoric acid esters of polyvinyl alcohol, polyvinylsulfonic acid, polyvinylbenzenesulfonic acid, sulfuric acid esters of polyvinyl alcohol and acetals of polyvinyl alcohols, which are formed by reaction with a sulfonated aliphatic aldehyde. It also suggests that one or more of these post-treatments can be carried out separately or in combination. More detailed descriptions of these treatments can be found in GB-A 1 084 070, DE-A 4 423 140, DE-A 4 417 907, EP-A 659 909, EP-A 537 633, DE-A 4 001 466, EP-A 292 801, EP-A 291 760 and US-P 4 458 005.

A carrier without a hydrophilic surface can coated with a hydrophilic layer, referred to as a primer layer become. The primer layer is preferably a cross-linked hydrophilic Layer made of a hydrophilic, with a hardener such as formaldehyde, glyoxal, Crosslinked polyisocyanate or a hydrolyzed tetraalkyl orthosilicate Binder is obtained. The latter crosslinking agent becomes special prefers. The strenght the hydrophilic primer layer can vary between 0.2 and 25 μm and is preferably between 1 and 10 μm.

The hydrophilic binder for use in the undercoat z. B. a hydrophilic (co) polymer such as Homopolymers and copolymers of vinyl alcohol, acrylamide, methylolacrylamide, Methylol methacrylamide, acrylic acid, methacrylic acid, Hydroxyethyl acrylate, hydroxyethyl methacrylate or maleic anhydride-vinyl methyl ether copolymers. The hydrophilicity of the (co) polymer or (co) polymer mixture used is preferably higher or equal to the hydrophilicity of at least 60% by weight, preferably to at least 80% by weight hydrolyzed polyvinyl acetate.

The amount of hardener, especially tetraalkyl orthosilicate, is preferably at least 0.2 part by weight per part by weight of hydrophilic Binder, is preferably between 0.5 and 5 parts by weight, particularly preferably between 1.0 part by weight and 3 parts by weight per part by weight of hydrophilic binder.

The hydrophilic primer layer can also substances that affect the mechanical strength and porosity of the layer improve, contain. Colloidal silica can be used for this purpose become. The colloidal silica can be in the form of any commercially available water dispersion of colloidal silica for example with an average particle size up to 40 nm, e.g. B. 20 nm, to be used. Next to it inert particles with a larger grain size than that colloidal silica be added, e.g. B. silica, which, as in J. Colloid and Interface Sci., Volume 26, 1968, pages 62 to 69, by Stöber is made, or alumina particles or particles with an average diameter of at least 100 nm, it being are particles of titanium dioxide or other heavy metal oxides. By embedding these particles, the surface of the hydrophilic primer layer a uniform rough texture with microscopic Peaks and valleys, which as bearings for Serve water in background areas.

Special examples of suitable ones hydrophilic undercoat layers for use in the present invention are disclosed in EP-A 601 240, GB-P 1 419 512, FR-P 2 300 354, U.S. Patent 3,971,660 and U.S. Patent 4,284,705.

It is particularly preferred to use a film carrier which is coated with an adhesion-promoting layer, also called an adhesive layer. Adhesion-improving layers which are particularly suitable for the use according to the invention contain a hydrophilic binder and colloidal silica, as described in EP-A 619 524, EP-A 620 502 and EP-A 619 525. The amount of silica in the adhesion-promoting layer is preferably between 200 mg / m ² and 750 mg / m ² . Furthermore, the ratio of silica to hydrophilic binder is preferably above 1 and the specific surface area of the colloidal silica is preferably at least 300 m ² / g, particularly preferably at least 500 m ² / g.

Imaging material

The imaging material contains at least one imaging layer applied to the lithographic base. Preferably only a single layer is applied to the base. The material can be light sensitive or heat sensitive, the latter choice being preferred because of the daylight resistance. The image recording layer of the material used according to the invention is preferably non-ablative. The term "non-ablative" means that the image recording layer is not significantly removed during the exposure step. The material can be positive-working, that is, the exposed areas of the imaging layer can be removed by the single-fluid ink, exposing the hydrophilic surface of the lithographic base which forms the non-printing areas of the master, while the non-exposed areas cannot be removed by the single-fluid printing ink and form the hydrophobic printing areas of the master. In a particularly preferred embodiment, the material is negative working, ie the unexposed areas of the image-recording layer are removed by the single-fluid printing ink, the hydrophilic surface of the lithographic base, which forms the non-printing areas of the master, being exposed, while that is not -exposed areas are not removed by the single-fluid printing ink and form the hydrophobic printing areas of the master. The term “removable or removed” means that the image recording layer can be removed from the lithographic base by supplying single-fluid ink, for example by dissolving the layer in the single-fluid ink or by forming a Dispersion or emulsion of the layer in the single-fluid printing ink.

In a preferred embodiment the imaging material is negative working and contains one Imaging layer that is exposed before exposure through the single-fluid ink can be removed and less easily removed by exposure is made. Below is a discussion of two very particularly preferred embodiments such a negative working imaging layer.

In a first very particularly preferred embodiment, the working mechanism of the image-forming layer is based on the thermally induced coalescence of hydrophobic thermoplastic polymer particles which are preferably dispersed in a hydrophilic binder, as described in e.g. B. EP 770 494 . EP 770 495 . EP 770 497 . EP 773 112 . EP 774 364 and EP 849 090 , The coalesced polymeric particles form a hydrophobic printing area that cannot be easily removed by the single-fluid ink, while the unexposed layer forms a non-printing area that is rapidly removable by the single-fluid ink. The thermal coalescence can be carried out by directly applying heat, e.g. B. with the aid of a thermal head, or by the light absorption of one or more compounds which are capable of converting light, particularly preferably infrared light, into heat. Particularly useful compounds that convert light into heat are, for example, dyes, pigments, carbon black, metal carbides, metal borides, metal nitrides, metal carbonitrides, oxides with a bronze structure and conductive polymer dispersions, such as conductive polymer dispersions based on polypyrrole, polyaniline or polythiophene. Infrared absorbing dyes and carbon black are particularly preferred.

The hydrophobic thermoplastic polymeric particles preferably have a coagulation temperature above 35 ° C and especially preferably over 50 ° C. Coagulation can result from softening or melting of the thermoplastic polymeric particles enter under the influence of heat. The coagulation temperature subject to the thermoplastic hydrophobic polymer particles Although no specific upper limit, it should be sufficiently below the decomposition temperature of the polymeric particles. The coagulation temperature is preferably at least 10 ° C under the temperature, during the decomposition of the polymer particles entry. As specific examples of hydrophobic polymeric particles are z. B. polyethylene, polyvinyl chloride, polymethyl (meth) acrylate, Polyethyl (meth) acrylate, polyvinylidene chloride, polyacrylonitrile, polyvinyl carbazole, Polystyrene or copolymers of the same. Very particularly preferred becomes polystyrene. The weight average molecular weight of the polymers can vary between 5,000 and 1,000,000 g / mol. The particle size of the hydrophobic Particles can be between 0.01 μm and 50 μm, particularly preferably between 0.05 μm and 10 μm and very particularly preferably between 0.05 μm and 2 μm lie. The amount of hydrophobic thermoplastic polymer particles in the image-forming layer is preferably between 20% by weight and 65% by weight, particularly preferably between 25% by weight and 55% by weight and very particularly preferably between 30% and 45% by weight.

Suitable hydrophilic binders are for example synthetic homo- or copolymers such as a polyvinyl alcohol, a poly (meth) acrylic acid, a poly (meth) acrylamide, a polyhydroxyethyl (meth) acrylate Polyvinyl methyl ether or natural Binders such as gelatin, a polysaccharide such as e.g. B. dextran, pullulan, Cellulose, gum arabic and alginic acid.

In the second very particularly preferred embodiment contains the imaging layer is an aryldiazosulfonate homopolymer or -Copolymer that is hydrophilic and soluble in single fluid printing ink before exposure is made hydrophobic and less soluble by the exposure becomes. For the exposure comes the same means as related above with the thermal coalescence of polymeric particles discussed in Question. Alternatively, the aryldiazosulfonate polymer can also by exposure to UV light such as B. with a W laser or W lamp can be switched.

in der R⁰, R¹ und R² unabhängig voneinander jeweils ein Wasserstoffatom, eine Alkylgruppe, eine Nitrilgruppe oder ein Halogenatom, z. B. Cl, bedeuten, L eine zweiwertige Verbindungsgruppe bedeutet, n 0 oder 1 bedeutet, A eine Arylgruppe bedeutet und M ein Kation bedeutet. L bedeutet vorzugsweise eine zweiwertige Verbindungsgruppe aus der Gruppe bestehend aus -(X)_t-CONR³-, -(X)_t-COO-, -X- und -(X)_t-CO-, wobei t 0 oder 1 bedeutet, R³ ein Wasserstoffatom, eine Alkylgruppe oder eine Arylgruppe bedeutet und X eine Alkylengruppe, eine Arylengruppe, eine Alkylenoxygruppe, eine Arylenoxygruppe, eine Alkylenthiogruppe, eine Arylenthiogruppe, eine Alkylenaminogruppe, eine Arylenaminogruppe, Sauerstoff, Schwefel oder eine Aminogruppe bedeutet. A bedeutet vorzugsweise eine nicht-substituierte Arylgruppe, z. B, eine nicht-substituierte Phenylgruppe, oder eine Arylgruppe, z. B. eine Phenylgruppe, die mit einer oder mehreren Alkylgruppen, Arylgruppen, Alkoxygruppen, Aryloxygruppen oder Aminogruppen substituiert ist. M bedeutet vorzugsweise ein Kation wie NH₄ ⁺ oder ein Metallion wie ein Kation von Al, Cu, Zn, ein Erdalkalimetall oder ein Alkalimetall.Preferred examples of such aryldiazosulfonate polymers are the compounds obtained by homo- or copolymerization of aryldiazosulfonate monomers with other aryldiazosulfonate monomers and / or with vinyl monomers such as (meth) acrylic acid or esters thereof, (meth) acrylamide, acrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, styrene, α -Methylstyrene etc. can be produced. Suitable aryldiazosulfonate polymers for use in the present invention correspond to the following formula

in which R ⁰ , R ¹ and R ² each independently represent a hydrogen atom, an alkyl group, a nitrile group or a halogen atom, e.g. B. Cl, L is a divalent linking group, n is 0 or 1, A is an aryl group and M is a cation. L preferably denotes a divalent connecting group from the group consisting of - (X) _t -CONR ³ -, - (X) _t -COO-, -X- and - (X) _t -CO-, where t denotes 0 or 1, R ^{3 represents} a hydrogen atom, an alkyl group or an aryl group and X represents an alkylene group, an arylene group, an alkyleneoxy group, an aryleneoxy group, an alkylene thio group, an arylene thio group, an alkylene amino group, an arylene amino group, oxygen, sulfur or an amino group. A preferably represents an unsubstituted aryl group, e.g. B, an unsubstituted phenyl group, or an aryl group, e.g. B. a phenyl group which is substituted with one or more alkyl groups, aryl groups, alkoxy groups, aryloxy groups or amino groups. M preferably denotes a cation such as NH ₄ ⁺ or a metal ion such as a cation of Al, Cu, Zn, an alkaline earth metal or an alkali metal.

Suitable aryldiazosulfonate monomers for the preparation of the above polymers are described in EP-A 339 393, EP-A 507 008 and EP-A 771 645. Typical examples are

The imaging material can besides that Image recording layer also other, on the lithographic Underlay applied applied layers. The light absorbing Connection can be in a different layer than that of the other above Ingredients like the hydrophobic thermoplastic polymer particles and the layer containing aryldiazosulfonate polymer is obvious, be included. Or the imaging material can be a protective top layer, which is removable by the single-fluid ink and protection against handling and mechanical damage. A contains a suitable protective cover layer Polyvinyl alcohol.

Single-fluid ink

Single-fluid printing inks suitable for use in the method according to the invention are described in US 4,045,232 . US 4,981,517 and US 6,140,392 , Single-fluid printing ink is generally understood to mean an emulsion of an ink phase in a polar phase or, conversely, an emulsion of a polar phase in an ink phase. The ink phase is also referred to as the hydrophobic or oleophilic phase. The polar phase preferably contains at least 50%, particularly preferably at least 70% and very particularly preferably at least 90% of a non-aqueous polar liquid. In a very particularly preferred embodiment, the polar phase consists of an organic polar liquid and is essentially anhydrous. The polar liquid is preferably a polyol. A very particularly preferred single-fluid printing ink is described in WO 00/32705, the relevant content of which is reproduced below.

The hydrophobic phase preferably contains a vinyl resin with carboxyl functionality. The term "vinyl resin" encompasses polymers which are prepared from vinyl monomers and monomers copolymerizable with vinyl monomers by chain reaction polymerization or addition polymerization via carbon-carbon double bonds. Typical vinyl monomers include, but are not limited to, vinyl esters, acrylic and methacrylic monomers, and aromatic styrene-containing vinyl monomers. The vinyl polymers can be branched using two reaction site monomers in the polymerization reaction. Even a branched vinyl polymer still has useful solubility. "Soluble" means that the polymer can be diluted with one or more solvents. (Contradictively, polymers can be cross-linked to form insoluble three-dimensional network structures that can only be achieved using solvents are swellable). Despite the substantial branching, the branched vinyl resins remain dilutable with solvents.

The vinyl polymers with a carboxyl function can by polymerizing a monomer mixture containing at least one monomer with an acid function or at least one monomer with a group resulting from the polymerization into an acid group how an anhydride group is converted contains. Examples for monomers with an acid function or anhydride function are u. a. in a non-limiting manner α, β-ethylenic unsaturated Monocarboxylic acids with 3 to 5 carbon atoms such as acrylic acid, methacrylic acid and Crotonic acid, α, β-ethylenic unsaturated dicarboxylic acids with 4 to 6 carbon atoms and the anhydrides and monoesters of these acids like maleic anhydride and fumaric acid and derivatives of copolymerizable monomers with an acid function like the hydroxylethyl acrylate half ester of succinic acid.

A monomer is preferably used an acid function like acrylic acid, methacrylic acid or crotonic acid or an anhydride monomer such as maleic anhydride or itaconic anhydride, which are hydrated after the polymerization to form acid groups can, embedded. The vinyl polymer having an acid function is preferred an acid number of at least about 3 mg KOH per gram of non-volatile material, preferably an acid number between about 6 and about 30 mg KOH per gram of non-volatile Material and very particularly preferably an acid number between about 8 and about 25 mg KOH per gram of non-volatile material based on the non-volatile Weight of the vinyl polymer.

In a preferred embodiment are the polymers with an acid function significantly branched. The printing inks used according to the invention contain preferably a vinyl polymer that is branched but useful soluble. The branched vinyl polymers can diluted by adding a solvent, rather than being swollen. The branching can take at least two Procedures are made. In a first procedure, a Monomer with two or more polymerizable double bonds in introduced the polymerization reaction. In a second procedure becomes a pair of ethylenically unsaturated monomers, each except the polymerizable double bond has at least one additional functionality that with the additional functionality capable of reacting to the other monomer contained during the Polymerization introduced into the monomer mixture. The reaction does occur the additional functional Groups preferably during the polymerization reaction, but this is not a critical condition and the reaction of the additional functional groups can be wholly or partly before or after the Polymerization take place. A diversity of such pairs of mutually reactive groups are possible. As an explanatory examples for such pairs of reactive groups are non-limitative Epoxy and carboxyl groups, amine and carboxyl groups, epoxy and amino groups, epoxy and anhydride groups, amino and anhydride groups, Hydroxyl and carboxyl or anhydride groups, amino and acid chloride groups, alkyleneimine and carboxyl groups, organoalkoxysilane and carboxyl groups, isocyanate and hydroxyl groups, cyclic carbonate groups and amino groups, Isocyanate and amino groups, etc. to name. Is one of the inserted reactive Groups a carboxyl group or anhydride group, they are in one sufficient excess used to give the required carboxyl functionality in the vinyl resin. For specific examples of such monomers count in a non-limiting manner glycidyl (meth) acrylate with (meth) acrylic acid, N-alkoxymethylated Acrylamides (which react with themselves) such as N-isobutoxymethylated Acrylamide, γ-methacryloxy trialkoxysilane (which reacts with itself) and combinations thereof.

The vinyl resin is preferably included at least one polymer with two or more polymerizable ethylenically unsaturated Polymerized bonds and particularly preferably with two to about four polymerizable ethylenically unsaturated bonds. explanatory examples for Monomers with two or more ethylenically unsaturated groups are non-limitative Way u. a. (Meth) acrylate esters of polyols such as 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, Tetramethylol methane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, Dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Alkylene glycol di (meth) acrylates and polyalkylene glycol di (meth) acrylates, such as ethylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, Diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate and polyethylene glycol di (meth) acrylate, divinylbenzene, allyl methacrylate, Diallyl phthalate, diallyl terephthalate and the like, which are individually or can be used in combinations of two or more. Out The above series are divinylbenzene, butylene glycol dimethacrylate, butanediol dimethacrylate, Trimethylolpropane triacrylate and pentaerythritol tetraacrylate in particular preferred and divinylbenzene is very particularly preferred.

The branched vinyl polymer is preferably polymerized with at least about 0.008 equivalents of at least one monomer having at least two ethylenically unsaturated polymerizable bonds per 100 g polymerized monomer or 0.004 equivalents per 100 g polymerized monomer of each of two monomers that are mutually reactive other than an ethylenically unsaturated polymerizable bond Groups included. The branched vinyl polymer is preferably used with about 0.012 to about 0.08 equivalents and particularly preferably with about 0.016 to about 0.064 equivalents of the polyfunctional monomer or monomers with at least two ethylenically unsaturated polymerizable bonds or polymerizes the pair of monomers with a polymerization bond and an additional reactive group per 100 g of polymerized monomer.

The polyfunctional monomer or the polyfunctional monomers preferably have between two and four ethylenically unsaturated polymerizable bonds and particularly preferably two ethylenically unsaturated polymerizable Bonds. In one embodiment the branched vinyl resin is preferably produced by polymerizing a mixture of monomers between about 0.5% and about 6%, particularly preferably between about 1.2% and about 6%, very particularly preferably between about 1.2% and about 4%, and even more preferably between about 1.5% and about 3.25% Divinylbenzene, based on the total weight of the polymerized Monomers. (Commercial Classes of divinylbenzene include a. monofunctional and / or non-functional material. The amount needed to get the percentages specified the standard Materials must be calculated become. So would for example 5% by weight of a material consisting of 80% by weight of divinylbenzene and 20% by weight of monofunctional monomers, 4% by weight of the Divinylbenzene portion).

The optimal amount in the polymerization mixture on (1) divinylbenzene or another monomer with at least two polymerizable ethylenically unsaturated bonds or (2) a pair of monomers with a polymerizable group and an additional so reactive group hangs to a certain extent of the respective reaction conditions such as the speed the addition of the monomers during polymerization, solubility of the polymer formed in the chosen Reaction medium, the amount of monomers, based on the reaction medium, the half-life of the chosen Initiator at reaction temperature and the amount by weight of the initiator, based on the monomers, and can be determined by simple testing become.

Other monomers, along with the polyfunctional monomers and the monomers with an acid function (or monomers with groups that are subsequently converted into acid groups can) polymerized can be are in a non-limitative way u. a. Esters of α, β-ethylenically unsaturated Monocarboxylic acids with 3 to 5 carbon atoms such as esters of acrylic acid, methacrylic acid and Crotonic acid, α, β-ethylenic unsaturated dicarboxylic acids with 4 to 6 carbon atoms and the anhydrides, monoesters and diesters of these acids, Vinyletter, vinylether, vinylketone and aromatic or heterocyclic aliphatic vinyl compounds. Typical examples of suitable ones Esters of acrylic acid, methacrylic acid and are crotonic acid in a non-limitative manner u. a. the esters by reacting with saturated aliphatic and cycloaliphatic alcohols with 1 to 20 carbon atoms are obtained, such as methyl, ethyl, propyl, isopropyl, n-butyl, Isobutyl, tert-butyl, 2-ethylhexyl, lauryl, stearyl, cyclohexyl, Trimethylcyclohexyl, tetrahydrofurfuryl, stearyl, sulfoethyl and isobornyl acrylates, methacrylates and crotonates and polyalkylene glycol acrylates and methacrylates. Typical examples of other ethylenically unsaturated polymerizable Monomers count compounds such as fumaric acid, maleic acid and Itakonsäureanhydride, Monoesters and diesters with alcohols such as methanol, ethanol, propanol, Isopropanol, butanol, isobutanol and tert-butanol. Typical examples of polymerizable Count vinyl monomers compounds such as vinyl acetate, vinyl propionate, Vinyl ethers such as vinyl ethyl ether, vinyl and vinylidene halides and Vinyl ethyl ketone. Typical examples of aromatic or heterocyclic aliphatic vinyl compounds count in a non-limiting manner, compounds such as styrene, α-methylstyrene, vinyltoluene, tert-butyl styrene and 2-vinyl pyrrolidone.

When choosing the monomers aimed One looks at various factors that are usually involved in the manufacturing process of printing ink varnishes taken into account be like the one you want Freezing point and the desired thinnability of the polymer obtained in the solvent or solvent system the ink composition.

The preferred vinyl polymers can be made by conventional techniques such as radical polymerization in a semi-batch process. The monomers, initiator (s) and eventual chain transfer agent (s) can be fed at a controlled rate in a semi-batch process into a suitable heated, solvent-loaded reactor. Typical sources of free radicals are organic peroxides such as dialkyl peroxides such as di-tert-butyl peroxide and dicumyl peroxide, peroxy esters such as tert-butyl peroxy-2-ethylhexanoate and tert-butyl peroxypivalate, peroxy carbonates and peroxydicarbonates such as tert-butyl peroxyisopropyl carbonate, di-2- ethylhexyl peroxydicarbonate and dicyclohexyl peroxydicarbonate, diacyl peroxides, such as dibenzoyl peroxide and dilauroyl peroxide, hydroperoxides, such as cumene hydroperoxide and tert-butyl hydroperoxide, ketone peroxides such as cyclohexanone peroxide and methyl isobutyl ketone peroxide, -3-peroxyketoxy, such as -peroxyketyl, such as -peroxyketyl, such as and 1,1-bis (tert-butylperoxy) cyclohexane, and azo compounds such as 2,2'-azobis- (2-methylbutanenitrile), 2,2'-azobis- (2-methyl) propionitrile and 1,1 ' azobis (cyclohexanecarbonitrile). Organic peroxides are preferred. Tert-butyl peroxyisopropyl carbonate is particularly preferred. Chain transfer agents can also be used in the polymerization. Typical chain transfer agents are mercaptans such as octyl mercaptan, n- or tert-dodecyl mercaptan, thiosalicylic acid, mercaptocarboxylic acids such as mercaptoacetic acid and mercaptopropionic acid and their esters and mercaptoethanol, halogenated compounds and dimeric α-methylstyrene. Preferably dispensing with the embedding of a chain transfer agent because of the smell and other disadvantages. The choice of initiator and amount of initiator depends on factors known to those skilled in the art, such as the reaction temperature, the amount and type of solvent (in the case of solution polymerization), the half-life of the initiator, etc.

The addition polymerization will usually at a temperature between about 20 ° C and about 300 ° C, preferably between about 150 ° C and about 200 ° C, particularly preferably carried out between about 160 ° C and about 165 ° C. The polymerization is preferably carried out at approximately the same reaction temperature and using the same initiator (s). The initiator should be chosen in this way be that of Half-life at the reaction temperature is preferably no longer than about thirty Minutes, particularly preferably not more than about five minutes and most preferably not more than about two minutes. Especially initiators with a half-life of less are preferred than about a minute at a temperature between about 150 ° C and about 200 ° C. In then usually a larger amount of the branching monomer to be embedded when the half-life of the initiator shorter and / or the amount of initiator higher is. The binders for the vinyl polymer in the printing ink preferably have no or a limited Content of residual (unreacted) monomer. The vinyl binder are in particular substantially free of residual monomer, i.e. H. contain less than about 0.5% by weight residual monomer, especially preferably less than about 0.1% by weight of residual monomer on the total weight of the polymerized monomers.

Be in a semi-batch process the monomer and the initiator over a certain period of time, preferably at constant speed, entered into the polymerization reactor. The rate of addition is usually between about 1 and about 10 hours and addition rates between about 3 and about 5 hours are common. Longer addition speeds usually result in lower number average molecular weights. Lower number average molecular weights are also available by increasing the ratio of solvent to monomer or by using a stronger solvent for the obtained Polymer.

Typically, the branched vinyl polymer used in the ink has a low number average molecular weight and a wide polydispersity. The number average molecular weight and weight average molecular weight of a vinyl resin used in the ink can be determined according to generally accepted methods by gel permeation chromatography based on a calibration with polystyrene standards, which are available for up to 6,000,000 weight average molecular weights. The polydispersity is defined as the M _w / M _n ratio. In a preferred embodiment, the vinyl polymer has a number average molecular weight (M _n ) of at least about 1,000, particularly preferably at least about 2,000. The number average molecular weight is also preferably less than about 15,000, more preferably less than about 10,000, and most preferably less than about 8,500. M _n is preferably between approximately 1,000 and approximately 10,000, particularly preferably between approximately 2,000 and approximately 8,500 and very particularly preferably between approximately 4,000 and approximately 8,000. The weight average molecular weight should be at least about 30,000, preferably at least about 100,000. The weight average molecular weight (M _w ) is preferably up to about 60,000,000, the determination by GPC against an available standard with 6,000,000 weight average molecular weights. M _w is preferably between approximately 30,000 and approximately 55,000,000, particularly preferably between approximately 100,000 and approximately 1,000,000 and very particularly preferably between approximately 100,000 and approximately 300,000. Resins having a very high, recognizable by GPC molecular weight shoulder in the curve (more than about 45,000,000) can be due to the -area M _w of between about 100,000 and about 300,000 preferably avoided. The polydispersity - ie the M _w / M _n ratio - can be up to about 10,000, preferably up to about 1,000. The polydispersity is preferably at least about 15, particularly preferably at least about 50. The polydispersity is preferably between about 15 and about 1,000, particularly preferably between about 50 and about 800.

The theoretical freezing point can be adjusted according to methods well known to those skilled in the art by selecting and dividing the usual factors. In a preferred embodiment, the theoretical T _{g is} above room temperature and preferably the theoretical T _{g is} at least about 60 ° C, particularly preferably at least about 70 ° C. In the processes and compositions according to the invention, preference is given to using vinyl polymers with a T _{g of} from approximately 50 ° C. to approximately 125 ° C., particularly preferably between approximately 60 ° C. and approximately 100 ° C., very particularly preferably between approximately 70 ° C. and approximately 90 ° C.

In one embodiment of the single fluid ink, the acidic vinyl polymer, which may be a branched vinyl polymer, is combined with other resins in the ink composition. Examples of suitable other resins which can be combined with the vinyl polymer having an acid function include, but are not limited to, polyester and alkyd resins, phenolic resins, rosin resins, cellulose resins and derivatives of these substances, such as rosin-modified phenol resins, phenol-modified rosin resins, hydrocarbon-modified rosin-modified malononium resins Rosin, fumaric acid modified rosin, hydrocarbon resin, other acrylic or vinyl resin, polyamide resin ze, etc. These resins or polymers can be used in an amount between about 6 parts by weight and about 1 part by weight based on the vinyl polymer having an acid function and based on the weight of non-volatile material in the resins.

Except for the vinyl resin with one acid function and an optional second resin contain the ink compositions preferably one or more solvents. In a preferred embodiment the single-fluid printing ink forms the branched vinyl resin solution or mock solution without visible cloudiness in the solvent or the solvents the ink composition. The solvent type and the amount solvent depend on the desired Viscosity, Ink consistency and stickiness. Usually used one for Printing inks during of the lithographic printing process in contact with rubber parts such as Rubber rollers come, non-oxygenated solvents or solvents with low Kauri-Butanol values (KB values) that are not due to the Soak in rubber. To suitable solvents for in Inks coming into contact with rubber parts count non-limiting aliphatic Hydrocarbons such as petroleum distillate fractions and normal and isoparaffin solvents with limited aromatic character. For example, petroleum middle distillate fractions are suitable like those under the trade name Magie Sol by Magie Bros. Oil Company, a subsidiary of the Pennsylvania Refining Company, Franklin Park, Ill., And under the trade name ExxPrint by Exxon Chemical Co., Houston, Texas, and Golden Bear Oil Specialties, Oildale, Calif., Total Petroleum Inc., Denver, Colo., And Calumet Lubricants Co., Indianapolis, Ind Petroleum middle distillate fractions. additionally or as an alternative you can soybean oil or other vegetable oils be used.

When using non-oxygenated solvents like the above must be in usually an adequate Amount of at least one monomer with substantial affinity for aliphatic solvents be embedded to the desired solubility of the preferred branched vinyl polymer. Usually can for this purpose acrylic acid ester monomers with at least six carbon atoms in the alcohol portion of the ester or styrene or alkylated styrene such as tert-butyl styrene in the polymerized monomers are embedded. In a preferred one embodiment contains an ink composition with non-oxygenated solvents a branched vinyl resin that consists of a monomer mixture that at least about 20%, preferably between about 20% and about 40%, and especially preferably between about 20% and about 25% of the aliphatic solubility promoting Monomers such as stearyl methacrylate or t-butyl styrene and preferably Contains stearyl methacrylate, is polymerized. Also preferably at least about 55% styrene, preferably between about 55% and about 80% styrene and more preferably between about 60% and about 70% styrene added. If requested also methyl methacrylate or other monomers to reduce compatibility of the solvent in an aliphatic solvent be used. All percentages are understood in weight, based on the total weight of the polymerized Monomer mixture. Preferred monomer compositions for vinyl polymers for lithographic Count inks a (meth) acrylic acid ester an alcohol with 8 to 20 carbon atoms, such as stearyl methacrylate, Styrene, divinylbenzene and (meth) acrylic acid. In a preferred embodiment becomes a branched vinyl polymer for a lithographic printing ink made between about 15, preferably about 20, and about 30, preferably about 25,% by weight of a (meth) acrylic acid ester an alcohol with 8 to 20 carbon atoms, in particular stearyl methacrylate, and between about 50, preferably about 60, and about 80, preferably about 75% by weight of a styrene monomer, in particular styrene itself, an amount of divinylbenzene as specified above and between about 0.5, preferably about 2.5, and about 5, preferably about 4,% by weight of one acrylic acid or particularly preferably contains a methacrylic acid.

The solvent or solvent mixture preferably has a boiling point of at least about 100 ° C and preferably not more than about 550 ° C on. With offset printing inks can solvent with a boiling point greater than about 200 ° C. compositions of new inks usually contain between about 20 and about 85% by weight of solvents like mineral oils, vegetable oils and high-boiling petroleum distillates. The amount of solvent also varies depending on the type of ink composition (i.e. H. is the ink for Newspaper printing, heatset printing, sheet printing etc.?), Type of used solvent and other factors known to those skilled in the art. The solvent content for lithographic Printing inks usually up to about 60%, with any oils as part of the solvent system to be viewed as. Usually contains the lithographic printing ink at least about 35% solvent. When assembling the preferred single-fluid printing ink, these are varnishes or binders, which includes the branched vinyl resins, usually clear dummy solutions.

The ink compositions generally contain one or more pigments. The number and type of pigments are determined by the type of ink to be assembled. Ink compositions for newspaper printing typically contain only one or a pair of pigments such as carbon black, while gravure inks can contain a more complex pigment system and can be composed in many colors, such as inks with special effects such as a pearlescent or metallic effect. Lithographic printing inks are generally used in four colors (magenta, yellow, black and cyan) and can be combined in such a way that a pearlescent or metallic effect is achieved. For the printing ink composition according to the invention can be any commercially available inorganic and organic pigments. The compositions can also be used as overprint varnishes or varnishes. The overprint varnishes (air drying) or overprint varnishes (hardening) should be clear or transparent. Therefore, opaque pigments are out of the question.

Compositions used according to the invention of lithographic printing ink are preferably used as single-fluid printing inks with a Oil-based dispersants, which contains the vinyl binder with an acid function, and a disperse, a liquid Polyol containing polyol phase. The vinyl polymer phase is relatively stable towards the polyol phase. The stability is sufficient to prevent separation of the two phases in the fountain solution. During the Applying the ink breaks the emulsion and gets there Polyol to the surface, where it wets the areas of the printing plate that must not attract ink. Printing inks that are stable in fountain solution but break quickly and then get onto the plate separately, ensure a clean one Print without staining and even transfer properties. A appropriate stability can also be of the type of vinyl polymer chosen with a acid function and the chosen one Depend on polyols. The acid number and molecular weight can so that the desirable stability is achieved.

Vinyl resins with higher acid numbers can be used in lower amounts be used, however the acid number must not be excessively high to avoid that Vinyl polymer not enough soluble in Hydrocarbon solvent is. As a rule, it is assumed that an increase in the acid number of the vinyl resin with an acid function with a decrease in the amount of such resin in the hydrophobic phase should go hand in hand.

Polyethylene glycol oligomers such as diethylene glycol, Triethylene glycol and tetraethylene glycol as well as ethylene glycol, propylene glycol and dipropylene glycol are examples of liquid polyols used for the polyol phase the used according to the invention Single fluid printing ink are preferred. Of course you can the polyol phase from a mixture of different liquid polyols consist. Typically, vinyl or acrylic polymers are lower acid number used in combination with higher molecular weight polyols. The polyol phase can contain other materials. Weakness Acid like Citric acid, Tartaric acid or tannic acid or a weak base like triethanolamine can be in an amount between about 0.01% and about 2% by weight based on the composition the printing ink. Certain salts such as magnesium nitrate can in an amount between about 0.01% and about 5% by weight, preferably in an amount between about 0.08% and about 1.5% by weight on the weight of the composition of the printing ink used to protect the plate and extend the life of the Contribute plate. For support a wetting agent such as polyvinylpyrrolidone may be used to wet the plate be added. The amount of polyvinyl pyrrolidone based on that Weight of the composition of the printing ink, varies between approximately 0.5 wt% and about 1.5 wt%.

It can use single fluid inks which are composed of between about 5% by weight and about 50% by weight, preferably between about 10% and about 35% by weight, and especially preferably between about 20% by weight and about 30% by weight of polyol phase, based on the total weight of the composition of the printing ink, contain. Unless another coolant is provided, preferably such an amount of polyol in the ink composition used that the Printing plate on an operationally acceptable cool Temperature is maintained. The required amount of polyol phase to Getting good tinting and printing results is dependent of the plate type used and can be determined by simple testing become. There can be up to about 4 or 5% by weight of water in the polyol phase mixture used to solve or to homogenize the ingredients of the polyol phase.

Experts are aware that others additives known to those skilled in the art in those used according to the invention Ink compositions can be used as long as such additives do not significantly affect the advantages of the present invention. explanatory examples for Additives are pour point lower, Surfactants, wetting agents, waxes, emulsifiers and dispersing agents, defoamers, Antioxidants, UV absorbers, drying agents (e.g. for compositions with vegetable oils), superplasticizer and other rheological property modifiers, gloss improvers and anti-settling agents. Any additives are usually in an amount of at least about 0.001% by weight, based on the ink composition, used and can in an amount of about 7% by weight or more based on the ink composition, be used.

feed roller

The imaging material is automatically fed to a platen of a printing press by being unwound from a supply reel or supply roll, ie a web of imaging material wound on the supply reel. The unwound imaging material is wound around a platen of the printing press, which is preferably the platen drum carrying the print master during the printing process. The supply roll is preferably located in the plate drum, as described in EP-A 640 478. However, the supply roll can also be arranged outside the plate drum. In this case, the unwound imaging material is wrapped around the drum and preferably automatically cut from the web on the supply roll. After printing, the printed material is preferably wound onto a take-up roll or take-up reel, which is preferably also arranged in the plate drum. Technical details about a preferred embodiment of such a device with built-in supply roll and take-up roll as well as the associated drive mechanism and tension control mechanism can be found in EP-A 640 478.

exposure level

The image forming material used according to the invention is exposed on the press, ie with material located on a drum of the printing press, preferably on the plate drum carrying the print master during the printing process, or is subjected to heat. The exposure or exposure to heat can e.g. B. with a thermal head, LED diodes or a laser head. One or more lasers such as an He / Ne laser, an Ar laser or a violet laser diode are preferred. The light used for the exposure is very particularly preferably not a visible light, so that daylight-resistant materials can be used, e.g. B. UV light (UV laser light) or near infrared light with a wavelength between about 700 and about 1,500 nm emitting laser, for. B. a semiconductor laser diode, an Nd: YAG laser or an Nd: YLF laser. The laser power required depends on the sensitivity of the image recording layer, the pixel dwell time of the laser beam, which is determined by the beam width (a typical value at 1 / e ^{2 of} the maximum intensity for modern imagesetters is between 10 and 25 μm), the scanning speed and the resolution of the imagesetter (ie the number of addressable pixels per unit length, often expressed as dots per inch or dpi - typical values are between 1,000 and 4,000 dpi). More technical details about on-press imagesetters can be found e.g. B. in US 5,174,205 and US 5 163 368 ,

stage of development

After exposure, the imaging layer by supplying single-fluid printing ink, preferably by means of the Ink application rollers of the printing press, the ink of the plate drum respectively, developed. The same single-fluid printing ink is preferably used in the Development stage and the subsequent pressure stage. In this embodiment the development and printing stages form a single process: After exposure, the printing process begins by using the material's single-fluid ink supplied becomes. After the first few revolutions of the printing drum (in the Usually less than 20, particularly preferably less than 10 revolutions) the image recording layer is completely developed and then over the Get high quality printed copies throughout the print cycle. As explained at the beginning the areas of the imaging layer that are soluble in single-fluid printing ink or have been solubilized by the exposure level, while the development stage removed. Preferably the removed ones Transfer components to the printing paper.

The development of imaging material with single fluid printing ink may precede an eventual stage in which the imaging layer first is wetted or in which you can by adding water or a aqueous liquid swell without trigger a substantial removal of the imaging layer.

EXAMPLES

1. Manufacturing a vinyl paint

An amount of 44.19 parts by weight Ketrul 220 (a petroleum middle distillate fraction from Total Petroleum, Inc.) is mixed in with a stirrer, a Nitrogen inlet, a reflux condenser with total reflux and one Monomer inlet equipped glass reactor filled. The solvent is stirring under nitrogen protective gas to 160 ° C heated. A monomer mixture of 36.01 parts by weight of styrene, 12.27 Parts by weight of stearyl methacrylate, 2.62 parts by weight of divinylbenzene, 1.89 parts by weight of methacrylic acid and 2.79 parts by weight of t-butyl peroxyisopropyl carbonate (75% solution in mineral spirits) is about Added to the reactor over 3 hours. After the addition of the monomer has ended 0.23 parts by weight of t-butyl peroxyisopropyl carbonate over a Period of 15 minutes added. The temperature becomes additional 2 h at 160 ° C kept to a complete Obtain conversion of the monomer to polymer.

The measured amount of non-liquid material (NVM) is 55%. The% conversion, measured as NVM divided by the percentage of the total weight of monomers, is 100.1. The acid number of the solution is 12.0 mg KOH / g. The viscosity is 30 stokes (bubble tube, 54.4 ° C). The solvent tole ranz is 230% and the NVM at the cloud point is 16.7%.

2. Manufacturing of single-fluid printing ink

• Gemisch A: Nach Vermischen von 181,0 g Diethylenglycol, 8,0 g Wasser, 0,4 g Zitronensäure und 0,4 g Magnesiumnitrat in einem Glasbecher, bis eine klare Lösung erhalten wird, werden 191,2 g Diethylenglycol zugesetzt und vermischt, bis eine homogene Lösung erhalten wird.
• Gemisch B: 46,0 g des obengenannten Vinyllacks, 4,0 g Blue Flush 12-FH-320 (erhältlich durch CDR Corporation, Elizabethtown, Ky.), 1,0 g technisches Sojaöl (erhältlich durch Cargill, Chicago, Ill.) und 0,6 g eines Antioxidans werden in einem Schnellrührer vermischt. Unter Vermischen werden 34,4 g einer Kohlenwasserstoffharzlösung (60% LX-2600 in EXX-Print 283D, erhältlich durch Neville), 27,0 g eines Gasrusses (CSX-156, erhältlich durch Cabot Corp.) und 1,0 g eines Polytetrafluorethylenwachses (Pinnacle 9500D, erhältlich durch Carrol Scientific) zugegeben. Das Mischen erfolgt über 30 Minuten hinweg bei hoher Mischgeschwindigkeit bei 149°C. Danach wird die Mischgeschwindigkeit verringert und werden 27,0 g EXX-Print 588D (erhältlich durch Exxon) zugegeben. Das Vorgemisch wird dann in einer Kugelmühle zu einem geeigneten Gemisch zermahlen.

58.0 g of the following mixture A are added to 142.0 g of the following mixture B with stirring. The ink composition is mixed in a vortex on a disperser for 20 minutes at a constant temperature below 60 ° C. The ink composition has a single laray fall time of between 14 and 17 s for 500 g at 30 ° C.

• Mixture A: After mixing 181.0 g of diethylene glycol, 8.0 g of water, 0.4 g of citric acid and 0.4 g of magnesium nitrate in a glass beaker until a clear solution is obtained, 191.2 g of diethylene glycol are added and mixed, until a homogeneous solution is obtained.
• Blend B: 46.0 g of the above vinyl paint, 4.0 g Blue Flush 12-FH-320 (available from CDR Corporation, Elizabethtown, Ky.), 1.0 g technical soybean oil (available from Cargill, Chicago, Ill.) and 0.6 g of an antioxidant are mixed in a high speed stirrer. With mixing, 34.4 g of a hydrocarbon resin solution (60% LX-2600 in EXX-Print 283D, available from Neville), 27.0 g of a carbon black (CSX-156, available from Cabot Corp.) and 1.0 g of a polytetrafluoroethylene wax (Pinnacle 9500D, available from Carrol Scientific) added. Mixing takes place over 30 minutes at high mixing speed at 149 ° C. Thereafter, the mixing speed is reduced and 27.0 g of EXX-Print 588D (available from Exxon) are added. The premix is then ball milled to a suitable mixture.

Mixture B has a laray viscosity between 180 and 240 poise and a laray yield between 800 and 1,200 on (measurement according to ASTM D4040 test method: power law –3 k, 1.5 k, 0.7 k, 0.3 k). Mixture B is at 1.200 rpm on the Inkometer for checked a measured result of 25 to 29 units.

3. Lithographic document

A layer of a 23.6% aqueous casting solution with a pH of 4 is applied to a PET web with a thickness of 0.175 mm in a wet layer thickness of 50 μm. After cooling for 30 seconds at 10 ° C., the layer is dried at a temperature of 50 ° C. and an atmospheric moisture content of 4 g / m ^{3 for} at least 3 minutes. The hydrophilic primer layer thus obtained contains 8,990 mg / m ² TiO ₂ , 900 mg / m ² SiO ₂ , 990 mg / m ² polyvinyl alcohol, 81.6 mg / m ² SAPONIN ^™ , 36.8 mg / m ² HOSTAPON ^™ and 605 mg / m ² FT248 ^TM .

SAPONIN is a non-ionic, consisting of esters and polyglycosides and sold by Merck Surfactant mixture. HOSTAPON T is an anionic surfactant manufactured by Hoechst AG is distributed. FT248 is an anionic perfluoro surfactant that is distributed by Bayer AG.

The above-mentioned TiO ₂ and SiO ₂ are added to the casting solution as a dispersion in polyvinyl alcohol. The TiO ₂ dispersion has an average particle size between 0.3 and 0.5 μm. The polyvinyl alcohol used is hydrolyzed polyvinyl acetate, which is sold by Wacker Chemie GmbH, Germany, under the trademark POLYVIOL WX ^TM . The above-mentioned SiO ₂ is added as a dispersion of hydrolyzed tetramethyl orthosilicate.

4. Image recording layer

A 2.61 wt .-% aqueous solution by mixing a polystyrene latex, a heat absorbing compound and a hydrophilic binder. This solution will Pour onto the hydrophilic primer layer of the PET carrier described above. After drying, the image-recording layer has a thickness of 0.83 µm on and contains 75% by weight of the polystyrene latex, 10% by weight of the infrared absorbent Dye IR-1 and as a hydrophilic binder 15 wt .-% polyacrylic acid (glass col E15, sold by N.V. Allied Colloids, Belgium).

5. Evaluation

A color station of a Quickmaster DI 46-4 (trademark of Heidelberger Druckmaschinen AG, Germany), which is a driographic digital press with built-in infrared laser diode exposure system and an unwinding spool arranged within the plate drum and Take-up spool is loaded with the above imaging material. To Exposure one starts the printing press and becomes the one described above Single-fluid ink supplied to the imaging layer. To The development stage is completed 10 revolutions and becomes clear deductions obtained without color attraction in the non-image areas.

Claims (10)

One identified by the steps below lithographic printing process (i) unwinding a path of a Imaging material from a supply reel, the imaging material (i) a pliable lithographic base with a hydrophilic surface and (2) an imaging layer which is removed by a single fluid ink or removable by exposure or exposure to heat with a single fluid ink can be made contains (Ii) Winding the imaging material onto a drum of a printing press, (Iii) imagewise exposure or exposure to heat the image recording layer, (iv) Development of the imaging layer by supplying single fluid ink, creating a print master will get (v) Printing by supplying single fluid ink to the print master mounted on a printing drum of the printing press, (Vi) Removal of the printing master from the printing drum. A method according to claim 1, characterized in that the Imaging layer a non-ablative imaging layer is that before exposure to or exposure to heat the single fluid ink can be removed and by exposure or exposure to heat is made less removable. A method according to claim 2, characterized in that the Image recording layer of hydrophobic thermoplastic polymer particles contains. A method according to claim 3, characterized in that the image recording layer further comprises a contains hydrophilic binder. A method according to claim 2, characterized in that the Image recording layer contains an aryldiazosulfonate polymer. Method according to one of the preceding claims, characterized characterized that the Supply spool is attached within the plate drum. Method according to one of the preceding claims, characterized characterized that step (vi) by winding the print master onto one inside the plate drum attached take-up reel. Method according to one of the preceding claims, characterized characterized that the flexible lithographic base a plastic carrier, a thin aluminum support or contains a laminate of a plastic carrier and a thin aluminum carrier. Method according to one of the preceding claims, characterized characterized that the Single fluid ink containing the following ingredients Is emulsion - on Dispersant containing a vinyl resin with an acid function, - a disperse Phase which is a liquid Contains polyol. A method according to claim 9, characterized in that this Vinyl resin is a branched vinyl resin with an acid function with a number average molecular weight between about 1,000 and about 15,000 and one Weight average molecular weight of at least about 100,000 is.