DE602005003007T2 - Development-free planographic printing plates - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

The The present invention relates to a lithographic printing process and a heat-sensitive printing plate precursor, for producing a lithographic printing plate by direct Printing plate imaging is suitable.

GENERAL PRIOR ART

at Lithographic printing machines use a so-called Druckmaster like a printing plate mounted on a drum of the printing press. The master surface enters lithographic image and a print is obtained by first printing ink applied to the image and then the color of the master a receiving material, usually paper, is transmitted. In conventional So-called lithographic wet printing both ink as Also water based fountain solution on the lithographic image, the from oleophilic (or hydrophobic, i.e. color-absorbing, water-repellent) And hydrophilic (or oleophobic, i.e. hydrophilic, ink-repelling) Areas constructed, appropriate. In so-called driographic The lithographic image consists of ink-receptive and ink-repellent prints (ie color repellent) Areas and will be during of driographic printing, just apply printing ink to the master.

print Master are usually by imagewise exposure and developing an image-forming apparatus called a plate precursor Materials received. Except the well-known radiation-sensitive, so-called presensitized Plates for a UV contact exposure through a film mask are suitable are in the late 90s also heat sensitive Printing plate precursors have become a very popular type of plate. Such Thermal materials have the advantage of their daylight resistance and are particularly suitable for use in the so-called computer-to-plate process (direct digital plate imaging) where the plate precursor is exposed directly, d. H. without the use of a film mask. The material comes with heat applied or exposed to infrared light and the generated thereby Heat dissolves you (physical) chemical process, such as ablation, polymerization, Insolubilization by crosslinking of a polymer, a thermal induced solubilization or coagulation of the particles of a thermoplastic polymeric latex.

In the most popular thermal plates, image formation occurs by heating the plates to cause a difference in solubility in alkaline developer between the heated areas and unheated areas of the coating. The coating usually contains an oleophilic binder, for. Example, a phenolic resin whose dissolution rate in the developer by the imagewise heating either limited (negative working plate) or increased (positive working plate) is. The difference in solubility causes the non-image areas (ie non-printing areas) of the coating to be removed during development, thereby exposing the hydrophilic support while leaving the image areas (ie the printing areas) of the coating intact on the substrate. Typical examples of such plates are described in e.g. B. EP-A 625 728 . EP-A 823 327 . EP-A 825 927 . EP-A 864 420 . EP-A 894,622 and EP-A 901 902 , Negative working embodiments of such thermal materials often require a preheating step between exposure and development as described in, e.g., US Pat. B. EP-A 625 728 ,

Certain These thermal processes allow plate production without wet development and are based, for example, on the ablation of one or more layers the coating, wherein in the exposed areas, the surface of a The underlying layer comes to rest, one to the surface of the non-exposed one Areas of coating have different affinities for printing ink or fountain solution. Thus, the image areas (printing Areas) and non-image areas or background areas (non-printing areas) receive.

In US 5,605,780 For example, there is disclosed a lithographic printing plate having an anodized aluminum support and an image-forming layer coated thereover comprising an IR absorber and a cyanoacrylate polymer binder. The image-forming layer is removed by laser-induced thermal ablation, exposing the underlying hydrophilic support.

In EP-A 580 393 discloses a lithographic printing plate directly imageable by laser discharge, wherein the plate has a first cover layer and a second layer under the first layer wherein the first layer is characterized by an efficient absorption of infrared radiation and the first layer and the second layer have a different affinity for at least one printing fluid.

In EP 1 065 051 there is disclosed a negative-working heat-sensitive material for making lithographic printing plates, the material comprising in sequence a lithographic base having a hydrophilic surface, an oleophilic imaging layer and a cross-linked hydrophilic cover layer. Under the influence of the heat generated during the exposure in the photosensitive layer, the hydrophilic cover layer is removed by ablation.

at Most ablative plates fall in ablation waste, pollution of electronics and optics can cause the exposure device and by wiping with a cleaning solvent of the pressure plate is to be removed. Because of this, are ablative Plates often not "real" process-free. which is on the plate surface may also affect the printing process and thereby cause, for example, toning.

Other thermal processes that allow plate-making without wet development are based, for example, on a thermally-induced hydrophilic / oleophilic conversion of one or more layers of the coating, wherein in the exposed areas, an affinity to ink or fountain solution to the surface of the non-exposed areas of the coating is obtained. Such coatings contain thermal switchable inorganic materials, e.g. Zirconia ceramics ( US 5,855,173 . US 5,839,369 and 5,839,370 ) or metal oxides ( EP 903 223 and US Pat. No. 6,455,222 ), or organic polymers as described in EP 924 102 . WO 92/09934 . EP 652 483 . US 4 081 572 . EP 200 488 and EP 924,065 ,

In WO 98/14504 and the Ph.D. thesis "New Polymers based on the quadruple hydrogen bonding motif", BJB Folmer, Eindhoven University of Technology, 2000 discloses supramolecular polymers containing monomer units linked by covalent bonds on at least one side in the supramolecular polymer and at least four together Hydrogen bonds can form.

In WO 02/053626 . WO / 053627 and US Pat. No. 6,506,536 there is disclosed an imaging element comprising a thermosensitive polymer having at least one covalently bonded moiety and at least one noncovalently bonded moiety having two center hydrogen bonds or even more centered moieties. After heating, the heat-sensitive polymer has increased solubility in an aqueous developing solution.

In US 2004/0023155 discloses an imaging element comprising supramolecular polymers containing four hydrogen-bond-modified (VWB-modified) hydrogen-bonded polymer molecules. The VWB-modified polymer molecules contain two VWB-modified parts A and B which are bonded to each other via a linking group, wherein part A and part B are a phenol resin, acrylic resin, polyester resin or polyurethane resin. Upon heating of the imaging member, the VWB-modified polymer molecules become soluble in alkaline developer.

BRIEF PRESENTATION OF THE PRESENT INVENTION

task The present invention is to provide one for manufacturing a heat sensitive lithographic printing plate suitable alternative printing plate precursor, which does not require a wet development step and directly by means of heated and / or exposed to a laser of low power output can.

Unexpectedly We have found that the coating of the heat-sensitive lithographic printing plate precursor according to the method of the invention when heated from hydrophilic to hydrophobic or hydrophobic to hydrophobic becomes. After exposure, the printing plate is ready for printing without further development.

• (i) Bereitstellen einer wärmeempfindlichen lithografischen Druckplattenvorstufe, die auf einem Träger, der eine hydrophile Oberfläche aufweist oder mit einer hydrophilen Schicht versehen ist, eine Beschichtung mit einem Polymer enthält, das mit zumindest zwei Gruppen, die vier Wasserstoffbrückenbindungen bilden können, modifiziert ist, wobei die Gruppen als "vierfache Wasserstoffbrückenbindungen" oder "VWB"-Gruppen definiert sind,
• (ii) Erwärmung und/oder Infrarotbelichtung der Druckplattenvorstufe, wobei die Beschichtung von hydrophil in hydrophob oder von hydrophob in hydrophil umgewandelt wird und dabei ohne Nassentwicklungszwischenschritt ein lithografischer Druckmaster erzeugt wird, und
• (iii) Auftrag von Druckfarbe und/oder Feuchtwasser auf den lithografischen Druckmaster mittels einer lithografischen Druckpresse. Gelöst wird die Aufgabe der vorliegenden Erfindung ebenfalls

durch eine Druckplattenvorstufe, die auf einem Träger, der eine hydrophile Oberfläche aufweist oder mit einer hydrophilen Schicht versehen ist, eine Beschichtung mit einem Polyether enthält, der mit zumindest zwei Gruppen, die vier Wasserstoffbrückenbindungen bilden können, modifiziert ist, wobei die Gruppen als "vierfache Wasserstoffbrückenbindungen" oder "VWB"-Gruppen definiert sind.The object of the present invention is achieved by a lithographic printing process characterized by the following steps:

• (i) providing a heat-sensitive lithographic printing plate precursor containing, on a support having a hydrophilic surface or provided with a hydrophilic layer, a coating with a polymer modified with at least two groups capable of forming four hydrogen bonds, wherein the groups as "quadruple hydrogen bonds" or "VWB" group are defined
• (ii) heating and / or infrared exposure of the printing plate precursor, wherein the coating is converted from hydrophilic to hydrophobic or from hydrophobic to hydrophilic, thereby producing a lithographic printing master without a wet development intermediate step, and
• (iii) application of printing ink and / or fountain solution to the lithographic printing master by means of a lithographic printing press. The object of the present invention is also solved

by a printing plate precursor containing, on a support having a hydrophilic surface or provided with a hydrophilic layer, a coating with a polyether which is modified with at least two groups capable of forming four hydrogen bonds, the groups being "fourfold Hydrogen bonds "or" VWB "groups are defined.

preferred embodiments The present invention is defined in the subclaims.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The Coating the printing plate precursor according to the method of the present invention Invention contains a at least two VWB group-containing polymer, hereinafter also as VWB-modified polymer designated. The VWB groups are attached via covalent bonds bound the polymer. The VWB groups can be the same or different be.

A VWB group is a group that has four hydrogen bonds to form (i.e., four-fold hydrogen bonds or VWB) and So over at least four hydrogen bonds another VWB group can be bound. Preferably, the VWB group contains two donor sites and two acceptor sites and are the hydrogen bonds preferably oriented parallel to each other. The VWB group has a substantially flat rigid structure, such as a plane six-membered ring. A preferred VWB group is an isocytosinyl group.

In the present invention, a VWB group present on one polymer may bond to a VWB group on another polymer, thus obtaining a structure with four-centered hydrogen-bond linked moieties. Schematically, such an association corresponds to the following structure:

Each VWB group on the modified polymer can form such a structure, thereby obtaining a so-called "supramolecular polymer." In the context of the present invention, the term "supramolecular polymer" thus refers to a polymer which has its polymeric properties covalently through a combination Bonds and secondary interactions, such as hydrogen bonds, in particular four-center hydrogen bonds or four-fold hydrogen bonds (VWB), receives. Such secondary interactions result in high bond strength and have a substantial influence on the properties of the modified polymers. In addition to hydrogen bonding, other secondary interactions may exist between the VWB units, such as van der Waals bonds, hydrophobic bonds, internal bonds, or combinations thereof. Schematically, a "supramolecular polymer" has the structure:

When Polymer having at least two VWB groups are phenolic resins, (meth) acrylic resins, Polyester resins, polyether resins, polyurethane resins or mixtures and Copolymers of the like are preferred.

in der R^a ein Wasserstoffatom, R^b eine Methylgruppe und Y eine von einem Diisocyanat der Formel Y(NCO)₂ abgeleitete Alkylengruppe bedeutet.The preparation of a VWB-modified polymer is carried out, for example, by reaction of, for example, an isocytosine, such as a 6-alkylisocytosine, usually 6-methylisocytosine, with an isocyanate, an isocytosine / isocyanate monoadduct, ie a four-fold hydrogen bonding unit (VWBE). , is obtained. The quadruple hydrogen bonding unit may then react with the appropriate polymer to form the VWB modified polymer. The 6-methylisocytosine / isocyanate monoadduct, a VWBE, has the formula:

wherein R ^{a is} a hydrogen atom, R ^{b is} a methyl group and Y is an alkylene group derived from a diisocyanate of the formula Y (NCO) ₂ .

By Reaction of 1 mole of isocytosine with 1 mole of the diisocyanate is The VWBE made, in turn, via a dimerization to a dimeric, by four thermally reversible hydrogen bonds linked Monoadduct forms. The dimeric VWBE thus obtained has on each end a free isocyanate group with the appropriate polymer, such as a (meth) acrylic polymer, a phenolic polymer, a polyester polymer, a polyether polymer or a polyurethane polymer may be a VWB-modified polymer such as a VWB-modified (Meth) acrylic polymer, a VWB-modified Phenol polymer, a VWB-modified polyester polymer, a VWB-modified Polyether polymer or a VWB-modified polyurethane polymer, to build.

One alternative process for the preparation of a VWB-containing polymer relates to the homopolymerization of a VWB-containing vinyl monomer unit. VWB-containing copolymers can by copolymerization of a VWB-containing vinyl monomer with other vinyl monomer units are obtained.

When Acrylic polymer can carboxyl-substituted acrylic polymers are used, such as. a. For example, polymers and copolymers of acrylic acid and / or methacrylic acid with for example, alkyl esters of acrylic acid, such as methyl acrylate and Ethyl acrylate, alkyl esters of methacrylic acid, such as methyl methacrylate and ethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, Hydroxypropyl acrylate, hydroxypropyl methacrylate, amides of acrylic acid, such as Acrylamide and N-methylacrylamide, amides of methacrylic acid, such as Methacrylamide and N-methylmethacrylamide, acrylonitrile, methacrylonitrile, Vinyl chloride, maleic anhydride, Itokonsäure, Vinylidene chloride, vinyl acetate, vinyl ether, styrene and N-phenylmaleimide.

Figur 1 in der:
R¹ und R² unabhängig voneinander ein Wasserstoffatom oder eine Kohlenwasserstoffgruppe mit bis 12 Kohlenstoffatomen bedeuten,
R³ ein Wasserstoffatom, eine Alkylgruppe, eine Fluoralkylgruppe, eine gegebenenfalls substituierte Phenylgruppe, eine gegebenenfalls substituierte Benzylgruppe, eine Pyridylgruppe, -OR, -COR, -COOR, -OCOR, -NHR, -CONHR, -NHCOR, -NHCOOR, -OCONHR, -NH-CO-NHR oder eine Kombination derselben bedeutet, wobei R ein Wasserstoffatom oder eine gegebenenfalls substituierte Alkylgruppe, Arylgruppe oder Heteroarylgruppe bedeutet,
R⁴ und R⁵ unabhängig voneinander ein Wasserstoffatom, ein Halogenatom, eine Alkoxygruppe oder eine gegebenenfalls substituierte Alkylgruppe, Arylgruppe oder Heteroarylgruppe bedeuten,
L¹ eine zweiwertige Verbindungsgruppe bedeutet,
m/n zwischen 100 und 0 liegt und das Molekulargewicht vorzugsweise zwischen 500 und 500.000 g/Mol liegt.In a preferred embodiment, the printing plate precursor according to the process of the invention contains a polymethacrylate or polyacrylate homopolymer or copolymer containing a structural unit having a covalently linked isocytosinyl group in the side chain. The structural units of the polymethacrylate or polyacrylate homopolymer or copolymer correspond, for example, to the following structures ( 1 ):

FIG. 1 in the:
R ¹ and R ² independently of one another denote a hydrogen atom or a hydrocarbon group having up to 12 carbon atoms,
R ^{3 is} a hydrogen atom, an alkyl group, a fluoroalkyl group, an optionally substituted phenyl group, an optionally substituted benzyl group, a pyridyl group, -OR, -COR, -COOR, -OCOR, -NHR, -CONHR, -NHCOR, -NHCOOR, -OCONHR , -NH-CO-NHR or a combination thereof, wherein R represents a hydrogen atom or an optionally substituted alkyl group, aryl group or heteroaryl group,
R ⁴ and R ⁵ independently of one another denote a hydrogen atom, a halogen atom, an alkoxy group or an optionally substituted alkyl group, aryl group or heteroaryl group,
L ^{1 represents} a divalent linking group,
m / n is between 100 and 0 and the molecular weight is preferably between 500 and 500,000 g / mol.

The substituents optionally contained in the phenyl group or benzyl group of R ³ may independently represent an alkyl group, a halogen atom such as a chlorine atom or bromine atom, a carboxylic acid group, a sulfonic acid group, a phosphonic acid group or a salt thereof or a hydroxyl group. The substituents optionally contained in the alkyl group, aryl group or heteroaryl group of R, R ⁴ and R ⁵ may independently represent a halogen atom such as a chlorine atom or bromine atom, a carboxylic acid group, a sulfonic acid group, a phosphonic acid group or a salt thereof or a hydroxyl group.

The divalent linking group L ¹ means an alkylene group such as a methylene group, an ethylene group, a propylene group, a butylene group, an isopropylene group, a cycloalkylene group such as a cyclohexylene group, an arylene group such as a tolylene group, or a heteroarylene group.

Figur 2 in der:
R⁶ und R⁷ unabhängig voneinander ein Wasserstoffatom oder eine Kohlenwasserstoffgruppe mit bis 12 Kohlenstoffatomen bedeuten,
R⁸ ein Wasserstoffatom oder eine gegebenenfalls substituierte Alkylgruppe, Arylgruppe oder Heteroarylgruppe bedeutet,
R⁹ und R¹⁰ unabhängig voneinander ein Wasserstoffatom, ein Halogenatom, eine Alkoxygruppe oder eine gegebenenfalls substituierte Alkylgruppe, Arylgruppe oder Heteroarylgruppe bedeuten,
m/n zwischen 100 und 0, besonders bevorzugt zwischen 50 und 0,01, ganz besonders bevorzugt zwischen 10 und 0,5 liegt und das Molekulargewicht vorzugsweise zwischen 500 und 500.000 g/Mol, besonders bevorzugt zwischen 800 und 100.000 g/Mol und ganz besonders bevorzugt zwischen 900 und 80.000 g/Mol liegt.Particularly preferably, the structural units of the polymethacrylate or polyacrylate homopolymer or copolymer correspond, for example, to the following structures ( 2 ):

FIG. 2 in the:
R ⁶ and R ⁷ independently of one another denote a hydrogen atom or a hydrocarbon group having up to 12 carbon atoms,
R ^{8 represents} a hydrogen atom or an optionally substituted alkyl group, aryl group or heteroaryl group,
R ⁹ and R ¹⁰ independently of one another denote a hydrogen atom, a halogen atom, an alkoxy group or an optionally substituted alkyl group, aryl group or heteroaryl group,
m / n is between 100 and 0, more preferably between 50 and 0.01, most preferably between 10 and 0.5 and the molecular weight preferably between 500 and 500,000 g / mol, more preferably between 800 and 100,000 g / mol and completely more preferably between 900 and 80,000 g / mol.

The substituents optionally contained in the alkyl group, aryl group or heteroaryl group of R ⁸ , R ⁹ and R ¹⁰ may independently represent a halogen atom such as a chlorine atom or bromine atom, a carboxylic acid group, a sulfonic acid group, a phosphonic acid group or a salt thereof or a hydroxyl group.

Figur 3 (I) Specific preferred structures of the polymethacrylate or polyacrylate copolymer include the following compounds I ( 3 ):

FIG. 3 (I)

Compound I-1

• R ¹¹ = R ¹² = R ¹³ = Me
• m / n = 10
• Mn = 1,000-50,000 g / mol

Compound I-2

• R ¹¹ = R ¹² = R ¹³ = Me
• m / n = 5.67
• Mn = 1,000-50,000 g / mol

Compound I-3

• R ¹¹ = R ¹² = R ¹³ = Me
• m / n = 4
• Mn = 1,000-50,000 g / mol

Compound I-4

• R ¹¹ = R ¹² = R ¹³ = Me
• m / n = 2.33
• Mn = 1,000-50,000 g / mol

Compound I-5

• R ¹¹ = H
• R ¹² = R ¹³ = Me
• m / n = 10
• Mn = 1,000-50,000 g / mol

Compound I-6

• R ¹¹ = H
• R ¹² = R ¹³ = Me
• m / n = 5.67
• Mn = 1,000-50,000 g / mol

Compound I-7

• R ¹¹ = H
• R ¹² = R ¹³ = Me
• m / n = 4
• Mn = 1,000-50,000 g / mol

Compound I-8

• R ¹¹ = H
• R ¹² = R ¹³ = Me
• m / n = 2.33
• Mn = 1,000-50,000 g / mol

phenolic polymers are common film-forming polymeric materials having numerous phenolic hydroxyl groups on the polymer backbone or as pendant groups on the polymer backbone. Preferred phenolic resins are novolak resins, resole resins, acrylic resins with lateral Phenolic groups and polyvinylphenol resins. Other usable phenolic resins are u. a. Polyvinyl compounds with phenolic hydroxyl groups. To include such compounds for example, polyhydroxystyrenes and copolymers having structural units of a hydroxystyrene, as well as polymers and copolymers with structural units substituted hydroxystyrenes.

Particularly preferred are novolak resins. Novolac resins are commercially available and well known to those skilled in the art. They are usually prepared by the condensation reaction of a phenol, such as phenol, m-cresol, o-cresol, p-cresol, etc., with an aldehyde, such as formaldehyde, paraformaldehyde, acetaldehyde, etc., or a ketone, such as acetone, in Presence of an acid catalyst. The weight average molecular weight is typically between about 1,000 and about 15,000 g / mole. Examples of typical novolac resins include phenol-formaldehyde resins, cresol-formaldehyde resins, phenol-cresol-formaldehyde resins, pt-butylphenol-formaldehyde resins and pyrogallol-acetone resins.

usable Polyester polymers can u. a. by reaction of dianhydride compounds with hydroxyl-containing, from dicarboxylic acid units and glycol units produce existing polyester precursors. Examples of usable hydroxyl-containing polyester precursors are u. a. Oligoester diols, the can be obtained by reaction of a dicarboxylic acid such as succinic acid, adipic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, tetrabromophthalic acid, tetrachlorophthalic acid, 1,4-cyclohexanedicarboxylic acid, maleic acid, fumaric acid, itaconic acid and 5-sodium, with a diol, such as ethylene glycol, diethylene glycol, triethylene glycol, Polyethylene glycol, 1,2- or 1,3-propanediol, Polypropylene glycol, 1,2- or 1,4-butanediol, neopentyl glycol or 1,6-hexanediol. examples for usable dianhydrides are u. a. Pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3 ', 4,4'-diphenyltetracarboxylic or 2,3,6,7-naphthalenetetracarboxylic dianhydride.

usable Polyurethane polymers can by reaction of diols having a carboxyl function with diisocyanates to be obtained. Examples of useful carboxyl-containing diols include Dimethylolpropionic acid, dihydroxybenzoic acids and the reaction product of a dianhydride such as pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3 ', 4,4'-diphenyltetracarboxylic or 2,3,6,7-naphthalenetetracarboxylic dianhydride, with a diol, such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1,2- or 1,3-propanediol, polypropylene glycol, 1,2- or 1,4-butanediol, Neopentyl glycol or 1,6-hexanediol.

Preferred polyethers which can be used are linear, cyclic or branched polyalkylene oxides, for example polyethylene oxide, polypropylene oxide, polybutylene oxide or mixtures and copolymers thereof. A preferred polyether is an ethylene oxide-propylene oxide copolymer. The polyalkylene oxides preferably contain one or more units of the formula -C _n H _2n -O-, in which n is preferably an integer between 2 and 5. The group -C _n H _2n - may contain straight or branched chains. The alkylene group may further contain optional substituents. The molecular weight of the polyether is preferably between 100 g / mol and 5,000 g / mol, more preferably between 150 g / mol and 2,000 g / mol, most preferably between 150 g / mol and 1,500 g / mol.

Figur 4 in der:
R¹⁴ und R¹⁵ unabhängig voneinander ein Wasserstoffatom, ein Halogenatom, eine Hydroxylgruppe, eine Alkoxygruppe oder eine gegebenenfalls substituierte Alkylgruppe, Arylgruppe oder Heteroarylgruppe bedeuten und
P¹ eine zweiwertige Gruppe mit einer wie oben beschriebenen Polyethergruppe bedeutet.In a further preferred embodiment, the printing plate precursor according to the invention contains a VWB-modified polyether. An example of a preferred VWB-modified polyether corresponds to the following structure ( 4 ):

FIG. 4 in the:
R ¹⁴ and R ¹⁵ independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkoxy group or an optionally substituted alkyl group, aryl group or heteroaryl group, and
P ^{1 represents} a divalent group having a polyether group as described above.

The substituents optionally contained in the alkyl group, aryl group or heteroaryl group of R ¹⁴ and R ¹⁵ may independently represent a halogen atom such as a chlorine atom or bromine atom, a carboxylic acid group, a sulfonic acid group, a phosphonic acid group or a salt thereof or a hydroxyl group.

Figur 5 in der:
R¹⁶ und R¹⁷ unabhängig voneinander ein Wasserstoffatom, ein Halogenatom, eine Hydroxylgruppe, eine Alkoxygruppe oder eine gegebenenfalls substituierte Alkylgruppe, Arylgruppe oder Heteroarylgruppe bedeuten,
L², L³, L⁴ und L⁵ unabhängig voneinander jeweils eine zweiwertige Verbindungsgruppe bedeuten und
P² eine zweiwertige Gruppe mit einer wie oben beschriebenen Polyethergruppe bedeutet.Particularly preferred VWB-modified polyethers have the following structure ( 5 ):

FIG. 5 in the:
R ¹⁶ and R ¹⁷ independently of one another denote a hydrogen atom, a halogen atom, a hydroxyl group, an alkoxy group or an optionally substituted alkyl group, aryl group or heteroaryl group,
L ² , L ³ , L ⁴ and L ⁵ are each independently a divalent linking group, and
P ^{2 represents} a divalent group having a polyether group as described above.

The substituents optionally contained in the alkyl group, aryl group or heteroaryl group of R ¹⁶ and R ¹⁷ may independently represent a halogen atom such as a chlorine atom or bromine atom, a carboxylic acid group, a sulfonic acid group, a phosphonic acid group or a salt thereof or a hydroxyl group.

The divalent linking groups L ² and L ⁵ denote an alkylene group such as a methylene group, an ethylene group, a propylene group, a butylene group, an isopropylene group, a cycloalkylene group such as a cyclohexylene group, an arylene group such as a tolylene group, or a heteroarylene group.

The divalent linking groups L ³ and L ⁴ denote an alkylene group such as a methylene group, an ethylene group, a propylene group, a butylene group, an isopropylene group, a cycloalkylene group such as a cyclohexylene group, an arylene group such as a tolylene group, a heteroarylene group, -O-, - O-CO-, -NH-, -O- (CH ₂ ) _k -, - (CH ₂ ) _k -O-, - (CH ₂ ) _k -O-CO-, -O-CO- (CH ₂ ) _k -, - (CH ₂ ) _k -O-CO- (CH ₂ ) _l -, - (CH ₂ ) _k -COO-, -CO-O- (CH ₂ ) _k -, - (CH ₂ ) _k - COO- (CH ₂ ) _l- , - (CH ₂ ) _k -NH-, -NH- (CH ₂ ) _k -, - (CH ₂ ) _k -CONH-, -NH- (CH ₂ ) _k -O- (CH ₂ ) ₁ -, - (CH ₂ ) _k -CO-, -NH-CO-, -NH-CO-O-, -O-CO-NH, - (CH ₂ ) _k -CO-NH-, -NH-CO- (CH ₂ ) _k -, -NH-CO-NH- or a combination thereof, wherein k and l are independently an integer of at least 1.

Figur 6 (II) Specific examples of preferred VWB-modified polyethers for use in the present invention include the following compounds II (US Pat. 6 ):

FIG. 6 (II)

Compound II-1

• R ¹⁸ = R ¹⁹ = CH ₃
• L ⁶ = L ⁹ = - (CH ₂ ) ₆ -
• L ⁷ = L ⁸ = -O-
• P ³ = polyethylene oxide (Mn = 200 g / mol)

Compound II-2

• R ¹⁸ = R ¹⁹ = H
• L ⁶ = L ⁹ = - (CH ₂ ) ₆ -
• L ⁷ = L ⁸ = -O-
• P ³ = polyethylene oxide (Mn = 200 g / mol)

Compound II-3

• R ¹⁸ = R ¹⁹ = CH ₃
• L ⁶ = L ⁹ = - (CH ₂ ) ₆ -
• L ⁷ = L ⁸ = -O-
• P ³ = polyethylene oxide (Mn = 300 g / mol)

Compound II-4

• R ¹⁸ = R ¹⁹ = CH ₃
• L ⁶ = L ⁹ = - (CH ₂ ) ₆ -
• L ⁷ = L ⁸ = -O-
• P ³ = polyethylene oxide (Mn = 400 g / mol)

Compound II-5

• R ¹⁸ = R ¹⁹ = CH ₃
• L ⁶ = L ⁹ = - (CH ₂ ) ₆ -
• L ⁷ = L ⁸ = -O-
• P ³ = polyethylene oxide (Mn = 900 g / mol)

Compound II-6

• R ¹⁸ = R ¹⁹ = CH ₃
• L ⁶ = L ⁹ = - (CH ₂ ) ₆ -
• L ⁷ = L ⁸ = -O-
• P ³ = polyethylene oxide (Mn = 1,000 g / mol)

Compound II-7

• R ¹⁸ = R ¹⁹ = CH ₃
• L ⁶ = L ⁹ = - (CH ₂ ) ₆ -
• L ⁷ = L ⁸ = -NH-
• P ³ = polyethylene oxide-polypropylene oxide copolymer (Mn = 600 g / mol)

Compound II-8

• R ¹⁸ = R ¹⁹ = CH ₃
• L ⁶ = L ⁹ = - (CH ₂ ) ₆ -
• L ⁷ = L ⁸ = -NH-
• P ³ = polypropylene oxide (Mn = 230 g / mol)

Compound II-9

• R ¹⁸ = R ¹⁹ = CH ₃
• L ⁶ = L ⁹ = 2,4,4-trimethylhexamethylene
• L ⁷ = L ⁸ = -O-
• P ³ = polyethylene oxide (Mn = 400 g / mol)

Compound II-10

• R ¹⁸ = R ¹⁹ = CH ₃
• L ⁶ = L ⁹ = - (CH ₂ ) ₆ -
• L ⁷ = L ⁸ = -O-
• P ³ = polypropylene oxide (Mn = 425 g / mol)

Preferably, the printing plate precursor further contains a monofunctional compound, ie, a compound having a single VWB group. Most preferably, the monofunctional compound is a VWB-modified polyether. The polyether is preferably a polymer having straight-chain, branched-chain or cyclic alkylene oxide units, such as ethylene oxide or propylene oxide units, or mixtures thereof having a molecular weight of between 100 and 5,000 g / mol, more preferably between 150 g / mol and 2,000 g / mol, and most preferably between 150 g / mol and 1500 g / mol.

Figur 7 (III) Specific monofunctional compounds correspond to the following compounds III ( 7 ) or VI ( 8th ):

FIG. 7 (III)

Compound III-1

• L ¹⁰ = -O-
• P ⁵ = polyethylene oxide (Mn = 400 g / mol)
• R ²⁰ = OH

Compound III-2

• L ¹⁰ = -NH-
• P ⁵ = polyethylene oxide-polypropylene oxide copolymer (Mn = 600 g / mol)
• R ²⁰ = NH ₂

Figur 8 (IV)

FIG. 8 (IV)

Compound IV-1

• L ¹¹ = - (CH ₂ ) ₆ -
• L ¹² = -O-
• P ⁶ = polyethylene oxide (Mn = 400 g / mol)
• R ²¹ = OH

Compound IV-2

• L ¹¹ = - (CH ₂ ) ₆ -
• L ¹² = -NH-
• P ⁶ = polyethylene oxide-polypropylene oxide copolymer (Mn = 600 g / mol)
• R ²¹ = NH ₂

The The present invention further provides a printing plate precursor with a VWB-modified polyether as described above. Possibly For example, the printing plate precursor may also be a monofunctional as described above Connection included.

The lithographic printing plate precursor support has a hydrophilic surface or is provided with a hydrophilic layer. The carrier may be a sheet-like material such as a plate or a cylindrical member such as a sleeve-shaped plate which can be slid around a printing drum of a printing press. The carrier is preferably a metal carrier such as an aluminum carrier or a carrier made of stainless steel.

A particularly preferred lithographic support is an electrochemically roughened and anodized aluminum support. The anodized aluminum support may be subjected to processing to improve the hydrophilic properties of the support surface. For example, by processing the support surface with a sodium silicate solution at elevated temperature, e.g. B. 95 ° C, silicate. Alternatively, a phosphate processing may be performed wherein the alumina surface is processed with an optional further inorganic fluoride-containing phosphate solution. Further, the alumina surface may be rinsed with a citric acid or citrate solution. This treatment can be carried out at room temperature or at a slightly elevated temperature between about 30 ° C and 50 ° C. Another interesting method is to rinse the alumina surface with a bicarbonate solution. Further, the alumina surface may be processed with polyvinylphosphonic acid, polyvinylmethylphosphonic acid, phosphoric acid esters of polyvinyl alcohol, polyvinylsulfonic acid, polyvinylbenzenesulfonic acid, sulfuric acid esters of polyvinylalcohol and acetals of polyvinylalcohols formed by reaction with a sulfonated aliphatic aldehyde. Further, it is obvious that one or more of these post treatments may be performed 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 U.S. Patent 4,458,005 ,

To a further embodiment can the carrier also a flexible carrier which is coated with a hydrophilic layer, hereinafter referred to as "primer layer" is. The flexible carrier is z. As paper, a plastic film, a thin aluminum substrate or a laminate of these materials. Preferred examples of plastic films are a film of polyethylene terephthalate, polyethylene naphthalate, Cellulose acetate, polystyrene, polycarbonate, etc. The plastic film carrier can opaque or translucent be.

The Primer layer is preferably a crosslinked hydrophilic layer, made of a hydrophilic, with a hardener such as formaldehyde, glyoxal, Polyisocyanate or a hydrolyzed tetraalkyl orthosilicate crosslinked 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 microns.

Specific examples of suitable hydrophilic primer layers for use in the present invention are disclosed in U.S. Patent Nos. 4,135,359 EP-A 601 240 . GB-P 1 419 512 . FR-P 2 300 354 . U.S. Pat. No. 3,971,660 and U.S. Patent 4,284,705 ,

in der X^– ein geeignetes Gegenion ist, wie Tosylat, Bromid oder Chlorid.The coating preferably also contains a compound that absorbs infrared light and converts the absorbed energy into heat. The amount of IR absorbing agent in the coating is preferably between 0.25 wt.% And 25.0 wt.%, More preferably between 0.5 wt.% And 20.0 wt.%. In a preferred embodiment, the ratio is at least 6% by weight, more preferably at least 8% by weight. The infrared absorbing compound may be contained in the image recording layer and / or any other layer. Preferred infrared absorbing compounds are dyes such as cyanine dyes, merocyanine dyes, indoaniline dyes, oxonol dyes, pyrilium dyes and squarilium dyes, or pigments such as carbon black. Examples of suitable IR absorbers are described in, for. B. EP-A 823 327 . EP-A 978,376 . EP-A 1 029 667 . EP-A 1 053 868 . EP-A 1 093 934 . WO 97/39894 and WO 00/29214 , A preferred compound of the following cyanine dye IR-1:

where X ^{- is} a suitable counterion such as tosylate, bromide or chloride.

Optionally, a protective layer may be further applied to protect the surface of the coating, particularly from mechanical damage. The protective layer generally contains at least one water-soluble polymeric binder, such as polyvinyl alcohol, polyvinylpyrrolidone, partially hydrolyzed Polyvinyl acetates, gelatin, carbohydrates or hydroxyethyl cellulose, and may be prepared by any known technique, such as from an aqueous solution or dispersion, which may, if necessary, contain minor amounts of organic solvents, ie, amounts below 5% by weight based on the total weight of the protective layer used coating solvents. The thickness of the protective layer can be chosen arbitrarily, is suitably up to 5.0 microns and is preferably between 0.05 .mu.m and 3.0 .mu.m, more preferably between 0.10 .mu.m and 1.0 .mu.m.

Except the Image recording layer, the coating may further one or several additional layers contain. Except the additional discussed above Layers - d. H. a possible light-absorbing layer with one or several compounds that are able to convert infrared light into heat, and / or a protective layer, such. B. one removed during development Cover layer - can the coating further includes, for example, one between the image recording layer and the carrier pasted adhesion-promoting Layer included.

Optional For example, the layer containing a light-absorbing compound or any other layer further containing additional ingredients, such as binders, surfactants such as perfluorosurfactants, silicon particles or titanium dioxide particles, or colorants.

According to the method of the invention becomes the obtained heat-sensitive Printing plate precursor either directly imagewise heated or indirectly with Infrared light, preferably near infrared light. The infrared light is preferably by an infrared light as discussed above absorbing compound in heat implemented. The printing plate precursor is insensitive to ambient light and therefore does not require a darkroom for its handling.

The printing plate precursor can be replaced by z. B. an LED or an infrared light laser are exposed to infrared light. Preferred for the exposure is a near infrared light having a wavelength between about 700 and about 1500 nm emitting laser, such. A semiconductor laser diode, an Nd: YAG laser or a Nd: YLF laser. The laser power required depends on the sensitivity of the imaging layer, the pixel dwell time of the laser beam as determined by the beam width (a typical value at 1 / e ^{2 of} the maximum intensity is between 10 and 25 μm for modern platesetters), the scanning speed and the resolution of the Gelichters (ie the number of addressable pixels per unit length, often expressed in dots per inch or dpi / typical values are between 1,000 and 4,000 dpi).

It are two types more common Laser imager, d. H. an inner drum plate setter (ITD platesetter) and an outer drum plate setter (XTD) plate-. ITD plate-setters for thermal plates usually by very high scanning speeds up to 1,500 m / s and sometimes need a laser power of several watts. The Agfa Galileo T (trademark by Agfa-Gevaert N.V.) is a typical example of one Platesetter of ITD technology. XTD platesetters work at a lower scanning speed, usually between 0.1 m / s and 20 m / s, and at a typical laser power per laser beam between 20 mW and 500 mW. The family of Creo Trendsetter platesetters (Trademark of Creo) and the family of Agfa Excalibur platesetters (Trademarks of Agfa-Gevaert N.V.) Both work on the basis the XTD technology.

The known platesetters are suitable for use as off-press imagesetters. The advantage of this application is that it reduces press downtime. XTD platesetter configurations are also suitable for on-press exposure, which has the advantage of immediate registration of the plate into a multi-color press. More detailed technical information on on-press-gelators are z. In US 5,174,205 and US 5,163,368 described.

At the exposure step can (can) optionally a rinsing step and / or a gumming step. The gumming step includes an after-treatment of the heat-sensitive Pressure plate with a gum solution. A gum solution is usually an aqueous one Liquid, the one or more surface protection compounds contains the lithographic image of a heat-sensitive material or a pressure plate to protect it from dirt or damage. suitable examples for such compounds are film-forming hydrophilic polymers or surfactants.

The thermosensitive Pressure plate is then without additional Development step ready for printing. The exposed printing plate can then into a conventional, so-called wet offset printing press, in the ink and fountain solution be mounted on the material to be clamped. The non-image areas keep the dampening water back, while the image areas hold back the ink.

In another suitable printing method so-called single-fluid printing ink is used without fountain solution. Suitable single-fluid printing inks are described in US 4,045,232 . US 4,981,517 and US 6,140,392 , In a most preferred embodiment, the single-fluid ink includes a paint phase, also referred to as a hydrophobic or oleophilic phase, and a polyol phase as described in U.S. Pat WO 00/32705 ,

In an alternative embodiment the pressure plate is first clamped on the printing cylinder of the printing press and then by means of a built-in gelator imaged directly on the press imagewise. The exposed printing plate is ready to print.

The according to the invention VWB-modified polyether-containing printing plate precursor may exposed and optionally treated with a gum solution or water (both steps are described in detail above was). In this way, a print master is obtained. The printing step may be performed as described above.

EXAMPLES PREPARATION OF THE LINKS

The chemicals used in the synthesis described below are commercially available. The Manufacturing process for 4-cyano-4 - [(phenylthioxomethyl) thio] pentanoic acid is described by S.H. Thang, B. Y.K. Chong, R.T.A. Mayadunne, G. Moad and E. Rizzardo in Tet. Lett. ", 1999, 40, 2435, described.

Preparation of Compounds I-3, I-6 and I-7

Preparation of 2-methyl-2 - [[[(1,4-dihydro-6-methyl-4-oxo-2-pyrimidinyl) -amin] -carbonyl] -amine] -ethyl methacrylate

5.0 g 2-Amino-4-hydroxy-6-methylpyrimidine are obtained by heating 170 ° C in Dissolved 65 ml of dimethyl sulfoxide. To this solution 6.8 g of isocyanatoethyl methacrylate are added. The mixture becomes 20 minutes stirred for a long time and then cooled in an ice bath. The resulting precipitate is diluted with acetone and then filtered to the desired To get final product. Yield = 7.0 g, 78%.

Preparation of Compound I-7

In a 0.5 liter three-necked flask is 1.52 g of acrylic acid, 1.48 g 2-Methyl-2 - [[[(1,4-dihydro-6-methyl-4-oxo-2-pyrimidinyl) -phenyl] -carbonyl] -amine] -ethyl methacrylate and 25 ml of 1-methoxy-2-propanol filled. To this solution you give afterwards 0.074 g of 4-cyano-4 - [(phenylthioxomethyl) thio] pentanoic acid and 0.067 g of 4,4'-azobis (4-cyanovaleric acid). The solution is then through 60 minutes Blown out of nitrogen degassed. The polymerization is through Heat of the mixture at 85 ° C fires after which the mixture was kept at this temperature for 5 hours becomes. Subsequently you leave cool the mixture, After which the precipitate is filtered off, washed with methylene chloride and finally is dried. Yield = 2.19 g, 73%, Mn = 11,310 g / mol.

Preparation of Compound I-3

For the production of Compound I-3 is proceeded and used analogously to Compound I-7 the following starting materials are used in the indicated amounts: methacrylic acid (2.21 g), 2 - [[[(1,4-dihydro-6-methyl-4-oxo-2-pyrimidinyl) -amine] -carbonyl] -amine] -ethyl methacrylate (1.79 g), methoxypropanol (40 ml), 4-cyano-4 - [(phenylthioxomethyl) thio] pentanoic acid (0.081 g) and 4,4'-azobis (4-cyanovaleric acid) (0.081 g). Yield = 3.0 g, 73%, Mn = 11,530 g / mol.

Preparation of Compound I-6

To a mixture of 2.96 g of acrylic acid and 2.04 g of 2 - [[[(1,4-dihydro-6-methyl-4-oxo-2-pyrimidinyl) -amine] -carbonyl] -amine] -ethyl methacrylate if 0.11 g of dimethyl 2,2'-azobisisobutyrate are added, 0.11 g of 2,4-diphenyl-4-methyl-1-pentene and 44.77 g of isopropanol. The Mixture is degassed for 3 minutes and then in a for 6 hours Nitrogen flow to 90 ° C heated. The product is collected by filtration, with acetone washed and dried. Yield = 2.9 g, 58%, Mn = 12,400 g / mol.

1.2. Preparation of compounds II-3, II-4 / IV-1 and II-7

Preparation of N- (1,4-dihydro-6-methyl-4-oxo-2-pyrimidinyl) -N '- (6-isocyanatohexyl) urea

These Production takes place on the basis of the thesis "New Polymers based to the quadruple hydrogen bonding motif ", B. J.B. Folmer, Technische universiteit Eindhoven, 2000, page 95.

72.0 Hexamethylene diisocyanate is added to a 100 ml flask and under a nitrogen atmosphere at 80 ° C heated. To this mixture is added 12.0 g of 2-amino-4-hydroxy-6-methylpyrimidine. The mixture is then at 100 ° C heated and stirred for 20 hours. Subsequently you leave Cool the mixture, then the precipitate is filtered off and washed with n-hexane. yield = 27.3 g, 97%.

Preparation of compound II-3

The Synthesis method is based on that described in the following document Methods: H.M. Keizer, R. van Kessel, R.P. Sijbesma and E.W. Meijer, Polymer, 2003, 44, 5505.

A solution of 2.55 g of polyethylene glycol (Mn = 300 g / mol) and 300 ml of toluene gets to 60 ° C heated, then at once 5.0 g of N- (1,4-dihydro-6-methyl-4-oxo-2-pyrimidinyl) -N '- (6-isocyanathexyl) urea and 5 drops Dibutyltin dilaurate are added. The mixture is stirred with 2.5 For hours under reflux Heated to 113 ° C, which is 105 ° C cooling down lets and then another 1.05 g of N- (1,4-dihydro-6-methyl-4-oxo-2-pyrimidinyl) -N '- (6-isocyanathexyl) urea added. Subsequently The mixture is heated under reflux for 5.5 hours. You can do that Mixture at 105 ° C cooling down, after which an additional 0.12 g of N- (1,4-dihydro-6-methyl-4-oxo-2-pyrimidinyl) -N '- (6-isocyanathexyl) urea was added become. Subsequently the mixture is refluxed for an additional 6.5 hours, after which it is allowed to cool to room temperature. The solvent is in vacuo removed and the solid residue extracted with warm methoxypropanol. The solvent is removed from the extract removed and the resulting solid washed with ethyl acetate. Yield = 4.5 g, 60%.

Preparation of a mixture of the compounds II-4 and IV-1

To a 6.0 g of N- (1,4-dihydro-6-methyl-4-oxo-2-pyrimidinyl) -N '- (6-isocyanatohexyl) urea and 4.0 g of polyethylene glycol (Mn = 400 g / mol) in 400 ml of methylene chloride and 40 ml of dimethyl sulfoxide-containing solution are added 5 drops of dibutyltin laurate. The mixture is subsequently Heated under reflux for 24 hours, after which it is allowed to cool to room temperature and the precipitate filtered off becomes. The filtrate is then reduced in vacuo to a solid, which in turn is processed with ethyl acetate and n-hexane. The so resulting solid is filtered off. Yield = 2.7 g.

Preparation of Compound II-7

5.0 g N- (1,4-dihydro-6-methyl-4-oxo-2-pyrimidinyl) -N '- (6-isocyanathexyl) -urea, 5.1 grams of Jeffamine ED-600 (trademark of Huntsman Corporation, CASRN 65605-36-9), 40 ml of methylene chloride, 40 ml of dimethyl sulfoxide and 5 Drops of dibutyltin dilaurate are placed in a 500 ml flask. The Mixture is heated under reflux for 24 hours with stirring. After subsequent Addition of 500 ml of methanol is filtered and the solvent removed from the filtrate. The desired product thus obtained is treated with ethyl acetate washed and dried. Yield = 9.2 g, 90%.

PREPARATION OF COATING SOLUTIONS

Inventive Example 1

One Mixture of compound II-4 and compound VI-1 is added to DMSO and the resulting mixture is heated with stirring to about 80 ° C until a clear solution is obtained. To this solution give IR-2 (Table 1).

Inventive Examples 2, 3 and 4

• (1): 2%ige wässrige Dispersion/Infrarot-Farbstoff IR-1 entspricht folgender Struktur:
  
  IR-1
• (2): 2%ige wässrige Dispersion/Infrarot-Farbstoff IR-2 entspricht folgender Struktur:
  
  IR-2

Compound I-3, I-6 or I-7 is added to a mixture of THF, water and triethylamine. To this solution is added IR-1 (Table 1). Table 1: Composition of the coating solutions ingredients Req. example 1 Req. Example 2 Req. Example 3 Req. Example 4 Compound II-4 (g) 1.31 - - - Compound VI-1 (g) 0.34 - - - Compound I-3 (g) - 0.5 - - Compound I-6 (g) - - 0.5 - Compound I-7 (g) - - - 0.5 Tetrahydrofuran (ml) - 5.94 5.94 5.94 Dimethyl sulphoxide (ml) 48.6 - - - Triethylamine (ml) 1.25 1.25 1.25 Ml water) 5.94 5.94 5.94 IR-1 (1) (ml) - 1.88 1.88 1.88 IR-2 (2) (ml) 0.25 - - -

• (1): 2% aqueous dispersion / infrared dye IR-1 has the following structure:
  
  IR-1
• (2): 2% aqueous dispersion / infrared dye IR-2 has the following structure:
  
  IR-2

MANUFACTURE OF PRINTING PLATES

The coating solutions be at 40 ° C by bar coating (layer thickness: 30 μm) on an anodised aluminum plate and then 10 minutes at 40 ° C (Examples of the invention 2, 3 and 4) and at 95 ° C (Inventive example 1) dried.

PRINT RESULTS

Subsequently, the plates are exposed by means of an emitting at 830 nm IR laser (Isomet diode) at the energy densities given in Table 3 below. Table 3: Exposure energy densities Power mW Drum speed m / s Energy density mJ / cm ² 4 200 714 4 140 500 4 100 357 8th 200 357 8th 100 179 8th 60 107

• * niedrigste Energie, bei der nach 250 Abzügen ein klares Bild erhalten wird.

The plate is then ready to print. The printing test is carried out using K + E Novavit 800 Skinnex printing ink (trademark of BASF Drucksysteme GmbH) and Agfa Prima FS101 fountain solution (trademark of Agfa) on a GTO 46 offset printing press (Heidelberger Druckmaschinen AG). The minimum sensitivity is defined as the lowest energy at which a clear image is obtained after 250 prints (Table 4). Table 4: Printing results image type minimum sensitivity * Inventive Example 1 positive image 179 mJ / cm ² Example 2 according to the invention negative image 714 mJ / cm ² Inventive Example 3 negative image 500 mJ / cm ² Example 4 according to the invention negative image 357 mJ / cm ²

• * lowest energy, giving a clear picture after 250 prints.

Out It can be seen from the results in Table 4 that in the example according to the invention 1, a positive-working printing plate is obtained and in the examples according to the invention 2, 3 and 4 a negative working printing plate is obtained. The highest Sensitivity becomes in the positive working printing plate of example according to the invention 1 received.

Claims (12)

A marked by the following steps lithographic printing process: (i) providing a heat-sensitive lithographic printing plate precursor mounted on a support, the a hydrophilic surface or provided with a hydrophilic layer, a coating containing a polymer, that with at least two groups, the four hydrogen bonds can form wherein the groups are defined as "four-fold hydrogen bonds" or "VWB" groups, (Ii) warming and / or infrared exposure of the printing plate precursor, wherein the Coating of hydrophilic in hydrophobic or hydrophobic in hydrophilic is converted and thereby without intermediate step wet development a lithographic printing master is produced, and (iii) Order of printing ink and / or dampening water on the lithographic printing master by means of a lithographic printing press. Method according to claim 1, characterized in that at least one of the VWB groups is an isocytosinyl group. Method according to claim 1 or 2, characterized that the polymer from VWB-modified phenolic resins, VWB-modified Poly (meth) acrylates, VWB-modified polyesters, VWB-modified polyethers, VWB-modified polyurethanes and blends and copolymers of the like chosen becomes. Method according to claim 3, characterized the polymer is a VWB-modified polyether. Method according to claim 4, characterized in that that the molecular weight of the VWB-modified polyether between 100 g / mol and 5,000 g / mol. Method according to one of claims 4 or 5, characterized that the VWB-modified polyether is a VWB-modified polyethylene oxide, a VWB-modified Polypropylene oxide or a mixture or copolymer is the like. Method according to claim 3, characterized the polymer is a VWB-modified (meth) acrylate homopolymer or (meth) acrylate copolymer having a structural unit having a Isocytosinyl group in the side chain. Method according to claim 7, characterized in that the molecular weight of the VWB-modified (meth) acrylate homopolymer or (meth) acrylate copolymer between 500 g / mol and 500,000 g / mol lies. A printing plate precursor mounted on a support, the a hydrophilic surface or provided with a hydrophilic layer, a coating containing a polyether, that with at least two groups, the four hydrogen bonds can form wherein the groups are defined as "four-fold hydrogen bonds" or "VWB" groups are. Printing plate precursor according to claim 9, characterized in that that the VWB group is an isocytosinyl group. Printing plate precursor according to claim 9 or 10, characterized characterized in that the molecular weight of the modified polyether between 100 g / mol and 5,000 g / mol. Printing plate precursor according to claim 11, characterized in that that the modified polyether is a VWB-modified polyethylene oxide, a VWB-modified polypropylene oxide or a mixture of both is.