DE602004011853T2 - Heat sensitive planographic printing plate precursor - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

The The present invention relates to a positive working lithographic Printing plate precursor, which is an aqueous-alkaline Development requires and an infrared dye having a perfluoroalkyl group contains.

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 lithographic printing is both ink and fountain solution water-based on the lithographic image, made of oleophilic (or hydrophobic, i.e., ink-receptive, 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 (i.e. H. ink-repelling) Areas and will be during of driographic printing, just apply printing ink to the master.

print Master are usually after the so-called computer-to-film process (data-driven film production) obtained where different pre-presses like the choice of typeface, scanning, making color separations, framing, trapping, layout and imposition digitally and each color separation via a platesetter on one graphic film is exposed. After development, the film as Mask for the exposure of an image-forming material, as a printing plate precursor designated, used and after the development of the plate becomes obtained a printing plate, which is used as a master.

A typical printing plate precursor for Computer-to-film method contains a hydrophilic carrier and an imaging layer with radiation-sensitive polymers Layers containing UV sensitive diazo compounds, dichromate sensitized contain hydrophilic colloids and a variety of synthetic photopolymers. In particular, diazosensitized layer dressings are becoming widespread used. For imagewise exposure, usually with the help of a film mask in a UV contact copying machine the exposed image areas are insoluble and the non-exposed areas remain soluble in aqueous alkaline developer. The printing plate is then Developed with the developer in the non-exposed areas to remove contained diazonium salt or diazo resin. The illuminated Areas thus form the image areas (ie the printing areas) of the printing master and thus become such printing plate precursors as "negative working" called. There are also positive-working materials in which the exposed Areas forming non-printing areas, e.g. B. plates with a novolak naphthoquinone diazide coating, which is only exposed in the Areas in the developer solved becomes.

Except the The above radiation-sensitive materials are also heat-sensitive Printing plate precursors known. Such materials include the Advantage of their daylight resistance and are particularly suitable for use in the so-called computer-to-plate method (direct digital plate imaging), where the plate precursor is direct is exposed, d. H. without the use of a film mask. Usually will the material with heat applied or exposed to infrared light and the generated thereby Heat dissolves you (physical) chemical process, such as ablation, polymerization, Insolubilization by cross-linking of a polymer or coagulation the particles of a thermoplastic polymeric latex and solubilization through destruction intermolecular interactions.

In US 5,466,557 there is described a positive-working printing plate precursor sensitive to both ultraviolet (UV) and infrared (IR) light but not to visible light, and a support and coating containing an aqueous-alkaline-developer-soluble oleophilic polymer and an aqueous solution latent Brönsted acid contains.

In EP-A 864 420 there is described a positive-working heat-sensitive printing plate precursor comprising a support, a first layer containing an oleophilic, aqueous-alkaline developer-soluble polymer, and an IR-sensitive overcoat, its permeability by the aqueous alkaline developer or solubility in the aqueous alkaline developer is changed by IR exposure.

In WO 97/39894 there is described a positive-working heat-sensitive printing plate precursor, which is sensitive to infrared light but not to ultraviolet light, and consists of a support and an IR-sensitive coating containing an aqueous-alkaline-developer-soluble oleophilic polymer and a solubilizer that reduces the solubility of the polymer in the developer.

In WO 99/21725 and WO 99/21715 there is described a positive-working heat-sensitive printing plate precursor whose coating contains a compound which enhances the resistance of the coating to developer. The compound is selected from the group consisting of poly (alkylene oxide), siloxanes and esters or amides of polyhydric alcohols.

In US 5,491,046 A method of imaging a positive-working and / or negative-working lithographic printing plate precursor is described wherein the image-forming layer contains a resole resin, a novolak resin, a latent Bronsted acid and an IR absorber. In one of the examples, a cyanine dye with a pentafluoropropionate counterion is described.

In EP 1 256 444 there is described a positive-working printing plate precursor comprising a coating comprising a first oleophilic phenolic resin-containing layer and further a second layer preventing the penetration of an aqueous-alkaline developer into the first layer over a period t2 and after exposure and / or heating allows the dissolution of the first layer in the aqueous alkaline developer over a period t1, wherein t2> t1 and t2 - t1 is at least 10 seconds.

In EP 1 162 078 there is described an imaging material comprising a substrate and an image-forming layer disposed on the substrate containing an infrared dye having at least one surface orientation group as a substituent for improving the sensitivity and / or image-forming ability of the imaging material.

The major problems with those known from the prior art Materials are (i) the weak differentiation between the development kinetics the exposed and unexposed areas, d. H. the dissolution of the exposed coating parts in the developer is not completely finished at the moment that even the unexposed Coating parts begin to dissolve in the developer, and (ii) diffusion of heat into the substrate, resulting in a reduction in the sensitivity of the printing plate precursor brings with it. this leads to to deductions low quality with blurred edges, toning (color attraction in exposed areas) and close development latitude.

BRIEF PRESENTATION OF THE PRESENT INVENTION

task The present invention is to provide a positive working one lithographic printing plate precursor with high differentiation between exposed and unexposed areas and high sensitivity. Solved These objects are achieved by the material defined in claim 1 and in the subclaims defined specific embodiments.

thanks Use of a water-repellent Compound in the second layer of the coating and of infrared dyes with specific substituents that the compatibility of the dye improve with the second layer of the coating, which is during the Infrared exposure generated heat concentrated in the second layer.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The lithographic printing plate precursor of the invention contains a support having a hydrophilic surface and a coating applied thereover. The coating comprises at least two layers, referred to as first and second layers in the present invention, the first layer being closest to the support, ie, located between the support and the second layer. The printing plate precursor is positive working, that is, after exposure and development, the exposed areas of the coating are removed from the support to form hydrophilic (non-printing) areas, while the unexposed coating is not removed from the substrate and forms an oleophilic (printing) area. The second layer is considered to serve as a barrier layer which prevents permeation of the aqueous alkaline developer into the oleophilic resin in the unexposed areas of the first layer. In exposed areas, the blocking function of the second layer may be smaller as a result of the exposure, and the dissolution of the coating in these areas may occur more rapidly upon immersion of the coating in aqueous alkaline developer. This weakening of the blocking function of the second layer caused by the exposure may e.g. Example by measuring the triggered by swelling of the oleophilic resin What be checked by both an exposed and unexposed sample. Typically, the exposed sample absorbs a small amount of water while the mean water uptake of unexposed samples is zero within a statistical error.

The blocking function of the second layer is based on the presence of a water-repellent compound. Suitable examples of such compounds are polymers with siloxane units and / or perfluoroalkyl units or block or graft copolymers with a poly (alkylene oxide) block or oligo (alkylene oxide) block and a block of polysiloxane units or oligosiloxane units and / or perfluoroalkyl units. The water-repellent polymer may be present in an amount between e.g. B. 0.5 and 15 mg / m ² , preferably between 0.5 and 10 mg / m ² , more preferably between 0.5 and 5 mg / m ² and most preferably between 0.5 and 2 mg / m ² be used. Depending on the hydrophobic / oleophobic degree of the compound, higher or lower amounts are also suitable. If the water-repellent polymer is also color-repellent, the use of amounts above 15 mg / m ² can lead to a weak color attraction of the unexposed areas.

In contrast, an amount below 0.5 mg / m ² can lead to an unsatisfactory development latitude, ie the exposed areas are not fully developed at the moment that even the unexposed areas begin to develop.

in der o, p, q, r und s eine ganze Zahl von mehr als 1 bedeuten.The block having the siloxane and / or perfluoroalkyl moieties may be a linear, branched, cyclic or complex crosslinked polymer or copolymer. The perfluoroalkyl moiety is z. A - (CF ₂ ) unit. The number of such units may be more than 10, preferably more than 20. The term "polysiloxane compound" includes any compound containing more than one siloxane group -Si (R, R ') - O- in which R and R' represent an optionally substituted alkyl or aryl group Preferred siloxanes are phenylalkylsiloxanes and dialkylsiloxanes The number of siloxane groups -Si (R, R ') - O- in (co) polymer is at least 2, preferably at least 10, more preferably at least 20. It may be less than 100, preferably less than 60 The alkylene block preferably contains 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-chain or branched chains The alkylene radical may also be optional Preferred embodiments and specific examples of such polymers are described in WO 99/21725 , A suitable water-repellent polysiloxane compound is preferably a random copolymer or block copolymer having siloxane groups and alkylene oxide groups, with a suitable number of siloxane units between about 15 and 25 and a suitable number of alkylene oxide groups between 50 and 70. Preferred polysiloxane is a copolymer of dimethyldichlorosilane, ethylene oxide and propylene oxide. Specific compounds are:

in which o, p, q, r and s are an integer greater than 1.

In Formula I is one of ethylene oxide units and propylene oxide units existing poly (alkylene oxide) block grafted onto a polysiloxane block. In formula II are long chain, from ethylene oxide units and propylene oxide units existing alcohols grafted onto a trisiloxane group.

The second layer may be both the oleophilic resin and the water repellent compound contain. However, the starting point is that block or graft copolymers, which is a poly (alkylene oxide) block or oligo (alkylene oxide) block and a block of polysiloxane or oligosiloxane and / or perfluoroalkyl units abstain while the coating due to their bifunctional structure at the interface between the coating solution and position the air, automatically creating a separate layer form, which corresponds to the second layer of the invention, even when incorporated as part of the oleophilic coating solution be applied.

The water-repellent But connection can also come from a second solution the first layer to be applied. In this embodiment it may be beneficial to use in the second coating solution solvent to be able to use that in the first layer to dissolve contained ingredients, whereby a phase of highly concentrated water-repellent polymer is obtained on the material becomes.

While it is Applicants' wish not to be limited by any theoretical explanation of the effect of their printing plate precursor, it is believed that spreading of the second layer onto the first layer is reduced by exposure. This is called "thermal dehumidification", ie the surface tension of the polysiloxane decreases to such an extent under the action of the generated heat that the second layer breaks up and an incomplete layer is formed which no longer completely protects the first layer from the developer For example, removal of the polysiloxane by wiping can be measured by measuring the ratio of the ¹ H NMR signals of the siloxane to the signals of the phenolic resin of a sample before wiping with a cotton swab Compare wiping with the same ratio after wiping.

The oleophilic resin is preferably an aqueous-developer-soluble polymer, more preferably a polymer soluble in an aqueous-alkaline developing solution having a pH of between 7.5 and 14. Preferred polymers are phenolic resins, e.g. Novolac, resoles, polyvinyl phenols, and carboxyl-substituted polymers. Typical examples of such polymers are described in DE-A 4 007 428 . DE-A 4 027 301 and DE-A 4 445 820 ,

The coating contains a perfluoroalkyl-containing infrared dye which makes the material sensitive to the IR light used in the exposure. The infrared dye is preferably a compound having an absorption maximum in the wavelength range between 750 and 1500 nm, so that a material resistant to daylight is obtained, which does not require a darkroom for its handling. By "daylight-insensitive material" is meant that exposure to visible light does not cause significant dissolution of the coating in the developer The infrared dyes of the invention are electrically charged and at least one perfluoroalkyl group bearing at least 6 fluorine atoms is contained in a counterion Dyes can also be covalently attached ne perfluoroalkyl group.

Of the Sensitizing dye can be in the first layer, in the above discussed second layer or in any other layer be embedded. It is assumed that the in the infrared dye contained perfluoroalkyl group the dye compatible with the water-repellent Makes connection and thus allows the dye to move faster in preferably the second layer, d. H. further away from the carrier, to position. As a result, the heat generated in the exposure in the concentrated second layer and achieved high sensitivity. The relationship the infrared absorbing compound in the coating is usually between 0.25 wt .-% and 10.0 wt .-%, particularly preferred between 0.5% by weight and 7.5% by weight.

in der:
-L¹- und -L²- unabhängig voneinander eine zweiwertige Verbindungsgruppe bedeuten, wie Alkylen, Arylen, Heteroarylen, -(CH₂)_t-O-, -(CH₂)_t-NH-, -(CH₂)_t-COO-, -(CH₂)t-COO-(CH₂)_u-, -(CH₂)_t-OCO-, -(CH₂)_t-OCO-(CH₂)_u-, -(CH₂)_t-CONH- oder -(CH₂)_t-CONH-SO₂- oder eine Kombination derselben,
-E¹ und -E² unabhängig voneinander eine neutrale, anionische oder kationische Endgruppe aus der Gruppe bestehend aus Alkyl, -OH, -H, -Cl, -Br, -F (neutrale Gruppen), -SO₃-, -SO₄-, -PO₃ ^2–, -PO₄ ^2–, -COO^– (anionische Gruppen) und -[NR^aR^bR^c]⁺ (kationische Gruppe) bedeuten,
wobei R^a, R^b und R^c unabhängig voneinander ein Wasserstoffatom oder eine Alkylgruppe bedeuten,
-A¹- und -A²- unabhängig voneinander -C_vF_2v-, -[(CF₂)₂-O]_w-, eine langkettige, zumindest vier Kohlenstoffatome enthaltende Alkylgruppe oder eine gegebenenfalls substituierte Alkylgruppe, Alkenylgruppe, Arylgruppe oder Aralkylgruppe bedeuten,
wobei p₁ und p₂ 0 oder 1 bedeuten,
wobei t und u 1 oder eine ganze Zahl über 1 bedeuten,
wobei v und w 2 oder eine ganze Zahl über 2 bedeuten,
-Y¹- und -Y²- unabhängig voneinander -CR⁹R¹⁰-, -S-, -Se-, -NR¹¹-, -CH=CH- oder -O- bedeuten,
R¹ bis R¹¹ unabhängig voneinander jeweils ein Wasserstoffatom, eine gegebenenfalls substituierte Alkylgruppe, Alkenylgruppe, Arylgruppe oder Aralkylgruppe oder ein Halogenatom, -NO₂, -O-R^d, -CO-R^d, -CO-O-R^d, -O-CO-R^d, -CO-NR^dR^e, -NR^dR^e, -NR^d-CO-R^e, -NR^d-CO-O-R^e, -NR^d-CO-NR^eR^f, -SR^d, -SO-R^d, -SO₂-R^d, -SO₂-O-R^d, -SO₂NR^dR^e oder eine Perfluoralkylgruppe bedeuten, wobei jede der besagten Gruppen gegebenenfalls eine oben als -E¹ und -E² definierte Endgruppe E umfassen kann und/oder zwei Nachbargruppen aus der Gruppe bestehend aus R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, Y¹ und Y² gemeinsam einen gegebenenfalls substituierten 5-gliedrigen oder 6-gliedrigen Ring bilden,
wobei R^d, R^e und R^f unabhängig voneinander ein Wasserstoffatom oder eine gegebenenfalls substituierte Alkylgruppe, Alkenylgruppe, Arylgruppe oder Aralkylgruppe bedeuten,
Z¹ und Z³ unabhängig voneinander jeweils ein Wasserstoffatom oder eine Alkylgruppe oder gemeinsam die zur Vervollständigung eines gegebenenfalls substituierten 5-gliedrigen oder 6-gliedrigen Ringes benötigten Atome bedeuten,
Z² einen Substituenten aus der Gruppe bestehend aus einem Wasserstoffatom, einem Halogenatom und einer gegebenenfalls substituierten Alkylgruppe, Aminogruppe, Arylthiogruppe, Alkylthiogruppe, Aryloxygruppe, Alkoxygruppe, Barbitursäuregruppe oder Thiobarbitursäuregruppe bedeutet,
X ein oder mehrere Gegenionen aus der Gruppe bestehend aus Cl^–, Br^–, I^–, F^–, D-SPO₃ ^–, D-SO₄ ^–, D-PO₄ ^2–, D-PO₃2^–, D-COO^–, D-[NR^gR^hRⁱ]⁺, ClO₄ ^– oder BF₄ ^– bedeutet,
wobei R^g, R^h und Rⁱ unabhängig voneinander ein Wasserstoffatom oder eine Alkylgruppe bedeuten,
wobei D C_jF_2j+1-, CF₃-[(CF₂)₂-O]_i-, eine Alkylgruppe, eine Arylgruppe oder eine substituierte Arylgruppe bedeutet,
wobei j 3 oder eine ganze Zahl über 3 bedeutet,
wobei i 1 oder eine ganze Zahl über 1 bedeutet,
vorausgesetzt, dass in obiger allgemeiner Formel III zumindest ein X eine Perfluoralkylgruppe ist.Preferred infrared absorbing compounds for use in the present invention correspond to the following general formula III:

in the:
-L ¹ - and -L ² - independently of one another denote a divalent linking group, such as alkylene, arylene, heteroarylene, - (CH ₂ ) _t -O-, - (CH ₂ ) _t -NH-, - (CH ₂ ) _t - COO-, - (CH ₂₎ t -COO- (CH _{2) u} -, - (CH _{2) t} -OCO-, - (CH _{2) t} -OCO- (CH _{2) u} -, - (CH _{2) t} -CONH- or - (CH ₂ ) _t -CONH-SO ₂ - or a combination thereof,
-E ¹ and -E ² are each independently a neutral, anionic or cationic end group selected from the group consisting of alkyl, -OH, -H, -Cl, -Br, -F (neutral groups), -SO ₃ -, -SO ₄ -, -PO ₃ ^2- , -PO ₄ ^2- , -COO ^- (anionic groups) and - [NR ^a R ^b R ^c ] ⁺ (cationic group),
wherein R ^a , R ^b and R ^c independently represent a hydrogen atom or an alkyl group,
-A ¹ - and -A ² - independently of one another -C _v F _2v -, - [(CF ₂ ) ₂ -O] _w -, a long-chain alkyl group containing at least four carbon atoms or an optionally substituted alkyl group, alkenyl group, aryl group or aralkyl group mean,
where p ₁ and p ₂ denote 0 or 1,
where t and u are 1 or an integer greater than 1,
where v and w are 2 or an integer greater than 2,
-Y ¹ - and -Y ² - independently of one another mean --CR ⁹ R ¹⁰ -, -S-, -Se-, -NR ¹¹ -, -CH = CH- or -O-,
R ¹ to R ¹¹ independently of one another each represent a hydrogen atom, an optionally substituted alkyl group, alkenyl group, aryl group or aralkyl group or a halogen atom, -NO ₂ , -OR ^d , -CO-R ^d , -CO-OR ^d , -O-CO- R ^d , -CO-NR ^d R ^e , -NR ^d R ^e , -NR ^d -CO-R ^e , -NR ^d -CO-OR ^e , -NR ^d -CO-NR ^e R ^f , -SR ^d , -SO-R ^d , -SO ₂ -R ^d , -SO ₂ -OR ^d , -SO ₂ NR ^d R ^e or a perfluoroalkyl group, each of said groups optionally having an end group defined above as -E ¹ and -E ² E may comprise and / or two neighboring groups from the group consisting of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , Y ¹ and Y ² together represent an optionally substituted 5-membered or Form 6-membered ring,
where R ^d , R ^e and R ^f independently of one another denote a hydrogen atom or an optionally substituted alkyl group, alkenyl group, aryl group or aralkyl group,
Z ¹ and Z ³ independently of one another each represent a hydrogen atom or an alkyl group or together represent the atoms required to complete an optionally substituted 5-membered or 6-membered ring,
Z ^{2 represents} a substituent selected from the group consisting of a hydrogen atom, a halogen atom and an optionally substituted alkyl group, amino group, arylthio group, alkylthio group, aryloxy group, alkoxy group, barbituric acid group or thiobarbituric acid group,
X is one or more counterions selected from the group consisting of Cl ^-, Br ^-, I ^-, F ^-, D-SPO ₃ ^-, D-SO ₄ ^-, D-PO ₄ ^2-, D-PO ₃ 2 ^-, D- COO ^-, D- [NR ^g R ^h R ^{i] +,} ClO ₄ ^- or BF ₄ ^- means
where R ^g , R ^h and R ^i, independently of one another, denote a hydrogen atom or an alkyl group,
where DC _{j is} F _{2j + 1} -, CF ₃ - [(CF ₂ ) ₂ -O] _i -, an alkyl group, an aryl group or a substituted aryl group tet,
where j is 3 or an integer greater than 3,
where i is 1 or an integer greater than 1,
provided that in general formula III above, at least one X is a perfluoroalkyl group.

Of the Infrared dye is negative or positively charged and neutralized the compound is at least one containing a perfluoroalkyl group Counterion X used with opposite charge. The dye may be anionic or cationic because of the chromophore and / or the fluorine-containing substituents on the chromophore and / or other substituents on the chromophore may be electrically charged. The Charge unit of the dye is represented by the sum of the positive and / or negative charges of the substituents on the dye, wherein for neutralizing the dye one or more counterions used with the above sum corresponding, opposite charge become. The charge unit of the counterions can be monovalent or polyvalent and / or be positive or negative.

In the embodiment in which -E ¹ and -E ^{1 represent} a neutral end group such as an alkyl group, -H, -H or -F, (and no other charged groups are present on the infrared dye), a negatively charged one also becomes Counterion X used that neutralizes the positively charged infrared dye. One of the end groups may be a cationic group, such as - [NR ^a R ^b R ^c ] ⁺ . In such a case the dye carries a single counterion with two negative charges (e.g. D-PO ₄ ^2-, D-PO ₃ ^2-.) Or two monovalent negatively charged counter ions (such as Cl ^-., Br ^-, I ^-, F ^- , D-SO ₃ ^- , D-SO ₄ ^- , D-COO ^- , ClO ₄ ^- or BF ₄ ^- ), provided that at least one counterion contains a perfluoroalkyl group. Depending on the nature of the end groups -E ¹ and -E ¹ and their charge unit, one or more counterions are needed to neutralize the infrared dye.

In another embodiment, Z ^{2 is} a negatively charged substituent, e.g. B. a negatively charged barbituric acid group.

in der R¹² und R¹³ unabhängig voneinander ein Wasserstoffatom, eine gegebenenfalls substituierte Alkylgruppe, Alkenylgruppe, Arylgruppe oder Aralkylgruppe oder eine Perfluoralkylgruppe, die gegebenenfalls eine oben als -E¹ und -E² definierte Endgruppe E enthalten können, bedeuten. Die negativ geladene Barbitursäuregruppe ist über * an die Heptamethingruppe gebunden.A negatively charged barbituric acid group has the following formula:

in which R ¹² and R ^{13 are} independently of one another a hydrogen atom, an optionally substituted alkyl group, alkenyl group, aryl group or aralkyl group or a perfluoroalkyl group which may optionally contain an end group E defined above as -E ¹ and -E ² . The negatively charged barbituric acid group is linked to the heptamethine group via *.

Preferred subclasses of the above infrared dyes correspond to the following formulas:

In the above formulas IV to XV, p ₁ , p ₂ , -L ¹ -, -L ² -, -E ¹ , -E ² , -A ¹ -, -A ² -, -Y ¹ -, -Y ² -, R ¹ to R ¹¹ , Z ² and X, the meaning assigned to these symbols in the above formula III.

Further preferred subclasses of infrared dyes are dyes according to formula III which further contain a perfluoroalkyl group covalently bonded to the dye. The indices / substituents p ₁ , p ₂ , -L ¹ , -L ² , -E ¹ , -E ² , -A ¹ -, -A ² -, -Y ¹ -, -Y ² -, R ¹ to R ¹¹ , Z ¹ , Z ² , Z ³ and X have the meaning assigned to these symbols in formula III above.

in denen:
m 2 oder eine ganze Zahl über 2 bedeutet,
R¹² und R¹³ unabhängig voneinander ein Wasserstoffatom, eine gegebenenfalls substituierte Alkylgruppe, Alkenylgruppe, Arylgruppe oder Aralkylgruppe oder eine Perfluoralkylgruppe, die gegebenenfalls eine oben als -E¹ und -E² definierte Endgruppe E enthalten können, bedeuten,
R¹⁴ -(CH₂)₂-OCO-(CH₂)₂-(CF2)_k-CF₃ bedeutet,
wobei k 2 oder eine ganze Zahl über 2 bedeutet, und
G SO3^–, SO4^– oder COO^– bedeutet.Further preferred subclasses of infrared dyes correspond to the formulas XVIII to XXI:

in which:
m 2 or an integer greater than 2,
R ¹² and R ¹³ independently of one another denote a hydrogen atom, an optionally substituted alkyl group, alkenyl group, aryl group or aralkyl group or a perfluoroalkyl group which may optionally contain an end group E defined above as -E ¹ and -E ² ,
R ^{14 is} - (CH ₂ ) ₂ -OCO- (CH ₂ ) ₂ - (CF ₂ ) _k -CF ₃ ,
where k is 2 or an integer greater than 2, and
G SO3 ^- , SO4 ^- or COO ^- means.

Specific examples of preferred infrared dyes for use in the present invention include the following compounds:

In addition to the preferred perfluoroalkyl-containing infrared dyes, the coating may contain additional infrared dyes such as cyanine dyes or cyanine pigments such as carbon black. Examples of suitable infrared 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 ,

The first layer may further contain other ingredients, such as additional binders which increase the run length of the plate, colorants, development inhibitors, as described in U.S. Patent No. 5,376,842 WO 97/39894 and EP-A 823 327 , or development accelerators such as 3,4,5-trimethoxybenzoic acid. The colorants are preferably dyes which remain in the unexposed areas of the coating during development and are washed away from the exposed areas to form a visible image. Preferably, such indicator dyes do not render the coating susceptible to visible light.

Suitable development accelerators are described in, for. B. EP-A 933,682 , Such compounds promote dissolution by reducing the dissolution time of the first layer. For example, cyclic acid anhydrides, phenols or organic acids are useful for improving the developability in aqueous solutions. Examples of the cyclic acid anhydride include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endoxy-4-tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, .alpha.-phenylmaleic anhydride, succinic anhydride and pyromellitic acid, as described in U.S. Pat US Pat. No. 4,115,128 , Examples of the phenols include bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ', 4 "-trihydroxytriphenylmethane and 4,4 ', 3 ", 4"-tetrahydroxy-3,5,3',5'-tetramethyltriphenylmethane and the like. Examples of the organic acids are Sulfonic acids, sulfinic acids, alkyl sulfuric acids, phosphonic acids, phosphates and carboxylic acids, as described in, for. B. JP-A 60-888 942 and JP-A 2-96755 , Specific examples of these organic acids include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethylsulfuric acid, phenylphosphonic acid, phenylphosphinic acid, phenylphosphate, diphenylphosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethylmethoxybenzoic acid, phthalic acid, terephthalic acid, 4- Cyclohexene-1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid and ascorbic acid. The amount of cyclic acid anhydride, phenol or organic acid in the image-forming composition is preferably between 0.05 and 20% by weight.

Of the carrier has a hydrophilic surface on or is provided with a hydrophilic layer. The carrier can a sheet-like material, such as a plate, or be a cylindrical Element, like a sleeve-shaped plate, which can be pushed around a printing drum of a printing press. Preferably, the carrier a metal carrier, like a carrier made of aluminum or 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.

The hydrophilic binder for use in the primer layer z. A hydrophilic (co) polymer such as homopolymers and copolymers of vinyl alcohol, acrylamide, methylolacrylamide, methylolmethacrylamide, Acrylic acid, methacrylic acid, Hydroxyethyl acrylate, hydroxyethyl methacrylate or maleic anhydride vinylmethyl ether copolymers. The hydrophilicity of the used (co) polymer or (co) polymer mixture is preferably higher or equal to the hydrophilicity of at least 60% by weight, preferably to 80% by weight hydrolyzed polyvinyl acetate.

The Lot of hardener, in particular tetraalkylorthosilicate, is preferably at least 0.2 parts by weight per part by weight of hydrophilic binder more preferably between 0.5 and 5 parts by weight, especially preferably between 1 part by weight and 3 parts by weight per part by weight hydrophilic binder.

The hydrophilic primer layer may also contain substances that improve the mechanical strength and porosity of the layer. Colloidal silica can be used for this purpose. The colloidal silica may be in the form of any commercial water dispersion of colloidal silica having, for example, an average particle size of up to 40 nm, e.g. B. 20 nm, are used. In addition, inert particles can be added with a larger particle size than the colloidal silica, z. B. Kie selsäure, which is prepared as described in J. Colloid and Interface Sci., Vol. 26, 1968, pages 62 to 69, by Stöber, or particles of toner or particles with an average diameter of at least 100 nm, which are particles of titanium dioxide or other heavy metal oxides. By embedding these particles, the surface of the hydrophilic primer layer is given a uniform rough texture with microscopic peaks and valleys that serve as reservoirs for water in background areas.

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 ,

Particularly preferred is a film carrier which is provided with an adhesion-promoting layer, also referred to as carrier layer. Particularly suitable adhesion promoting layers for use in the present invention include a hydrophilic binder and colloidal silica, as described in US 5,256,237 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 . Further, the ratio of silica to hydrophilic binder is preferably more than 1 and the specific surface area of the colloidal silica is preferably at least 300 m ² / g, more preferably at least 500 m ² / g.

The printing plate precursor according to the invention can by means of z. B. an LED or a laser head are exposed. Preference is given to one or more lasers or a laser diode. Preferred for exposure is infrared light having a wavelength between about 750 and about 1500 nm, preferably a laser such as a semiconductor laser diode, a 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 Exposure (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 need sometimes a laser power of several watts. The Agfa Galileo T (trademark of Agfa-Gevaert N.V.) is a typical example for one Platesetter of ITD technology. XTD platesetters work at a lower scanning speed, which is usually between 0.1 m / s and 20 m / s, and have 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 the Agfa Excalibur Platesetter (trademark of Agfa-Gevaert N.V.) both work on the basis of XTD technology.

The known platesetters are suitable for use as off-press imagesetters, which offers the advantage of reducing 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 imagesetter are z. In US 5,174,205 and US 5,163,368 described.

in the Development step will be the unexposed areas of the coating by immersion in an aqueous-alkaline Developer removed, optionally in combination with mechanical Wipe, z. B. by means of a brush roller. The step of development may include a drying step, a rinsing step, connect a gumming step and / or a post-bake step.

The printing plate thus obtained is suitable for conventional, so-called wet offset printing, in which printing ink and fountain solution are applied to the plate. In another suitable printing method so-called single-fluid printing ink is used without fountain solution. Suitable single-fluid printing inks for use in the method according to the invention are described in US 4,045,232 and US 4,981,517 , 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 ,

EXAMPLES

Synthesis of infrared inks

Synthesis of IR-1 (Reference Infrared Dye)

Product 1 + Product 2 + Product 3 → IR-1

Produkt 1

Product 1

Produkt 2

Product 2

3 Mole of product 2 are dissolved in 5 liters of methyl ethyl ketone and 6 liters of toluene. Then 8 l of solvent are distilled off, after which 3 moles of 1,1'-carbonyldiimidazole (Product 3) and 1 mol of product 1 are added and stirred at 100 ° C for 30 minutes. The addition of acetone and methanol initiates the precipitation of the product. (Yield = 78%)

Synthesis of Intermediate 1

Product 4 + Product 5 → Product 1

Produkt 4

Product 4

Produkt 5

Product 5

In a mixture of 8 l of methanol and 4 l of methylene chloride are l Mol of product 4, 1 mol of product 5 and 1.5 mol of potassium acetate 3 hours stirred at room temperature. The addition of methyl ethyl ketone triggers the precipitation of the product. product 1 is filtered off, washed with water and dried. (Yield = 67%)

synthesis of the intermediate 4

Product 6 + Product 7 → Product 4

Produkt 6

Product 6

Produkt 7

Product 7

To a mixture of 2 l of methanol and 0.25 l of triethylamine become 2 Mole Product 6, 1 mol of product 7 and 0.2 l of acetic anhydride and 2 hours at 60 ° C touched. Product 4 is filtered off and dried. (Yield: 40%)

Synthesis of Intermediate 6

Product 8 + Product 9 → Product 6

Produkt 8

Product 8

1 Mole of product 8 and 1.1 moles of 2-bromoethanol (product 9) are allowed 4 hours long at 100 ° C stirred in 2 l sulfolane. After adding acetone drops the product out. Product 6 is filtered off and dried. (Yield = 85%)

Synthesis of Intermediate 7

10 Mole of dimethylformamide and 3 moles of phosphoryl chloride are heated to 65 ° C. Subsequently 1 mol of cyclopentanone is added dropwise to this mixture, after which the mixture 1 hour at 60 ° C touched becomes. The reaction mixture is then dissolved in 2 liters of 7 moles of sodium acetate poured water containing. Product 7 is filtered off and dried. (Yield = 60%)

Synthesis of Intermediate 5

Product 12 + Product 13 → Product 5

Produkt 12

Product 12

1 Mole of product 12, 1.05 moles of malonic acid (Product 13), 0.5L toluene, 0.18L acetic acid and 0.25L acetic anhydride be 2.5 hours at 100 ° C touched. The reaction mixture is poured into a mixture of methanol and water poured, after which product 5 is filtered off and dried. (Yield = 44%)

Synthesis of Intermediate 12

Product 14 + Product 3 → Product 12

Produkt 14

Product 14

2 Mole of product 14 and 1 mole of 1,1'-carbonyldiimidazole (Product 3) are stirred for 30 minutes at 90 ° C. The reaction mixture is poured into a mixture of methanol and water, followed by product 12 filtered off and dried. (Yield = 28%)

Synthesis of IR-2 (Reference Infrared Dye)

Product 15 + Product 2 + Product 3 → IR-2

IR-2

IR-2

Produkt 15

Product 15

3 Mole of product 2, 1 l of methyl ethyl ketone and 5 l of toluene are mixed and about 4 liters of solvent distilled off, after which 3 mol of 1,1'-carbonyldiimidazole (Product 3) and 1 mol of product 15 are added and the thus obtained Mixture for 30 minutes at 100 ° C touched becomes. By adding 8 l of ethyl acetate, the precipitation of the Product triggered. IR-2 is filtered off and dried. (Yield = 85%)

Synthesis of Intermediate 15

Product 6 + Product 16 → Product 15

Produkt 16

Product 16

1 Mol of product 16, 2 moles of product 6, 2 moles of triethylamine and 1.6 moles acetic acid be 45 minutes at 50 ° C touched. Addition of ethyl acetate initiates the precipitation of the product. product 15 is filtered off and dried. (Yield = 93%)

Synthesis of Intermediate 16

0.8 1 N, N-dimethylformamide and 3 moles of phosphoryl chloride are mixed and at 60 ° C heated. Subsequently 1 mol of cyclohexanone is added dropwise to this mixture, after which the mixture 4 hours at 60 ° C is stirred. The mixture is in 4 l of 8 moles of sodium acetate-containing water cast. The precipitated product is filtered off and to a Mixture of 1.5 liters of acetone and 0.5 liters of water. 2.1 moles of indole and 2.3 moles of concentrated acid chloride are added and the mixture is stirred for 4 hours at room temperature. product 16 is filtered off and dried. (Yield = 68%)

Synthesis of IR-3

Product 19 + Product 20 → IR-3

Produkt 19

Product 19

Produkt 20

Product 20

1 1 mole of product 19, 1.2 moles of product 20 and 16 liters of methanol stirred long at room temperature. IR-3 is filtered off and dried. (Yield = 71%)

Synthesis of Intermediate 19

Product 21 + Product 22 → Product 19

Produkt 21

Product 21

Produkt 22

Product 22

1 Mole of product 22, 2 moles of product 21, 2 liters of acetic acid, 3 liters of triethylamine and 1 1 acetic anhydride are mixed and stirred at 60 ° C for 2 hours. Product 19 is filtered off and dried. (Yield = 57%)

Synthesis of Intermediate 21

1 Mole of product 8 and 2 moles of n-butyl bromide are added for 4 hours 100 ° C in 0.5 l sulfolane stirred. product 21 is filtered off, washed with ethyl acetate and dried. (Yield = 61%)

Synthesis of Intermediate 22

0.8 1 N, N-dimethylformamide and 3 moles of phosphoryl chloride are mixed and at 60 ° C heated. Subsequently this mixture is 1 equivalent Cyclohexanone was added dropwise and the mixture was stirred at 60 ° C for 4 hours. The mixture is in 4 l of 8 moles of sodium acetate-containing water cast. The precipitated product 22 is filtered off and dried.

Synthesis of IR-4

Product 24 + Product 2 + Product 3 → IR-4

Produkt 24

Product 24

3 Mole of product 2 are dissolved in 5 l of methyl ethyl ketone and 15 l of toluene. Approximately 10 liters of solvent are distilled off, after which 3 mol of 1,1'-carbonyldiimidazole (product 3) and 1 mol of product 24 are added and the resulting mixture 15th For minutes at 90 ° C touched becomes. The reaction mixture is poured into methanol. IR-4 will filtered off and dried. (Yield = 45%)

Synthesis of Intermediate 24

1 Mol of product 15 and 1.2 moles of product 20 are dissolved in 1 liter of methanol and 1 l of methylene chloride dissolved. The mixture is then stirred for 30 minutes at room temperature, after which the methylene chloride is evaporated and replaced with methanol. Product 24 is filtered off and dried. (Yield = 69%)

IR COMP1

Commercially available product, CASRN 134127-48-3

IR-COMP1

IR COMP1

Synthesis of IR-COMP2

 Product 25 + Product 5 → IR-COMP2

Produkt 25

Product 25

IR-COMP2

IR COMP2

1 Mol of product 25 and 1 mol of product 5 are dissolved in 15 l of methanol and 7 l methylene chloride dissolved. After addition of 2 moles of potassium acetate, the mixture is at 3 hours 40 ° C stirred. To Evaporation of methylene chloride is filtered from COMP-2 and dried. (Yield = 46%)

Synthesis of Intermediate 25

Product 21 + Product 26 → Product 25

Produkt 26

Product 26

1 Mol of product 26 and 2 moles of product 21 become 2 liters of acetic anhydride and 2.2 mol of triethylamine. The mixture is kept for 2 hours stirred at room temperature, after which 40 liters of ethyl acetate are added. Product 25 is filtered off and dried. (Yield = 30%)

Synthesis of Intermediate 26

Product 7 + Product 27 → Product 26

Produkt 27

Product 27

1 Mol of product 7 and 2 moles of product 27 are dissolved in 5 l of acetone and 2 l Water dissolved and stirred for 1 hour at room temperature. Product 26 is filtered off and dried. (Yield = 80%)

EXAMPLES 1 to 6

These Explain examples the use of perfluoroalkyl-containing infrared dyes in a coating according to the invention, in the water repellent Compound is a polysiloxane-containing polymer.

Production of the carrier

A 0.30 mm thick aluminum foil is degreased by immersing the foil in an aqueous solution containing 5 g / l of sodium hydroxide at 50 ° C and rinsed with demineralized water. The film is then electrochemically roughened with AC at a temperature of 35 ° C. and a current density of 1200 A / m ² in an aqueous solution containing 4 g / l of hydrochloric acid, 4 g / l of hydrobromic acid and 5 g / l of aluminum ions. to obtain a surface topography with an arithmetic mean roughness Ra of 0.5 μm.

To flush with demineralized water, the aluminum foil with a aqueous, 300 g / l sulfuric acid containing solution 180 s at 60 ° C etched and subsequently 30 s at 25 ° C rinsed with demineralised water.

Subsequently, the film is anodized at a temperature of 45 ° C, a voltage of about 10 V and a current density of 150 A / m ² for about 300 s in an aqueous solution containing 200 g / l of sulfuric acid to form an anodic, 3, 00 g / m ² Al ₂ O ₃ containing oxidation film, then washed with demineralized water, then processed in turn with a solution containing polyvinylphosphonic acid and a solution containing aluminum trichloride and finally rinsed 120 s at 20 ° C with demineralized water and dried.

Plate precursor materials

The solutions listed in Table 1 below are applied in a wet layer thickness of 20 microns to the carrier prepared as above and dried at 130 ° C for 1 minute. The materials are then exposed at different energy density values varying between 80 mJ / cm ² and 200 mJ / cm ² (exposure intensity on the image plane) using a Creo Trendsetter 3244 (830 nm). Thereafter, the plates are developed by immersing for 60 seconds in a development tank filled with (Agfa-supplied aqueous alkaline) DP300 developer at a temperature of 25 ° C. The sensitivity to infrared light of the various compositions corresponds to the minimum energy density adjustment required to achieve a 50% reduction in the light absorption of the coating in areas exposed to 50% area coverage (@ 200 lpi), the Measurement is carried out on the developed plate at the maximum wavelength of the contrast dye.

• * Alnovol SPN452 ist eine 40,5%ige Lösung in Dowanol PM (erhältlich durch Clariant),
• ** Triarylmethan-Farbstoff, erhältlich durch BASF,
• *** ein polysiloxanhaltiges Polymer, erhältlich durch Tego Chemie, Essen, Deutschland/10 gew.-%ige Lösung in Methoxypropanol,
• **** ein polysiloxanhaltiges Polymer, erhältlich durch Tego Chemie, Essen, Deutschland/10 gew.-%ige Lösung in Methoxypropanol.
• °BS = Bezugsbeispiel

The results in Table 1 show that the coatings containing a perfluoroalkyl-containing infrared dye have a higher sensitivity than the comparative coatings in which the corresponding infrared dyes contain no perfluoroalkyl group. Table 1 Ingredients (g) BS ° 1 BS ° 2 Ex. 3 (required) Ex. 4 (required) Ex. 5 (compare) Ex. 6 (compare) tetrahydrofuran 25.76 25.76 25.76 25.76 25.76 25.76 Alnovol SPN452 * 6.59 6.59 6.59 6.59 6.59 6.59 methoxypropanol 16,98 16,98 16,98 16,98 16,98 16,98 IR-1 0.1 - - - - - IR-2 - 0.1 - - - - IR-3 - - 0.1 - - - IR-4 - - - 0.1 - - IR COMP1 - - - - 0.1 - IR COMP2 - - - - - 0.1 Flexo blue 630 ** 0.03 0.03 0.03 0.03 0.03 0.03 Tego Glide 410 *** 0.14 0.14 0.14 0.14 0.14 0.14 Tego Wet 265 **** 0.05 0.05 0.05 0.05 0.05 0.05 2,3,4-trimethoxy 0.36 0.36 0.36 0.36 0.36 0.36 IR sensitivity (mJ / cm ² ) 120 90 120 80 > 200 > 200

• * Alnovol SPN452 is a 40.5% solution in Dowanol PM (available from Clariant),
• ** triarylmethane dye, available from BASF,
• *** a polysiloxane-containing polymer, available from Tego Chemie, Essen, Germany / 10% by weight solution in methoxypropanol,
• **** a polysiloxane-containing polymer, available from Tego Chemie, Essen, Germany / 10% strength by weight solution in methoxypropanol.
• ° BS = reference example

EXAMPLES 7 to 12

These Explain examples the use of perfluoroalkyl-containing infrared dyes in a coating according to the invention, in the water repellent Compound is a perfluoroalkyl-containing polymer.

Production of the carrier

Of the carrier is prepared analogously to Examples 1 to 6.

Plate precursor materials

The solutions listed in Table 2 below are applied in a wet thickness of 20 microns to the carrier prepared as above and dried at 130 ° C for 1 minute. The materials are then exposed at different energy density values varying between 80 mJ / cm ² and 200 mJ / cm ² (exposure intensity on the image plane) using a Creo Trendsetter 3244 (830 nm). Thereafter, the plates are developed by immersing for 60 seconds in a development tank filled with (Agfa-supplied aqueous alkaline) DP300 developer at a temperature of 25 ° C. The sensitivity to infrared light of the various compositions corresponds to the minimum energy density adjustment required to achieve a 50% reduction in the light absorption of the coating in areas exposed to 50% area coverage (@ 200 lpi), the Measurement is carried out on the developed plate at the maximum wavelength of the contrast dye.

• * Alnovol SPN452 ist eine 40,5%ige Lösung in Dowanol PM (erhältlich durch Clariant),
• ** Triarylmethan-Farbstoff, erhältlich durch BASF,
• *** ein perfluoralkylhaltiges Polymer, erhältlich durch 3M/10 gew.-%ige Lösung in Methoxypropanol.
• °BS = Bezugsbeispiel

The results in Table 2 show that the coatings containing a perfluoroalkyl-containing infrared dye have a higher sensitivity than the comparative coatings in which the corresponding infrared dyes contain no perfluoroalkyl group. Table 2 Ingredients (g) BS ° 7 BS ° 8 Ex. 9 (required) Ex. 10 (required) Ex. 11 (compare) Ex. 12 (compare) tetrahydrofuran 25.76 25.76 25.76 25.76 25.76 25.76 Alnovol SPN452 * 6.59 6.59 6.59 6.59 6.59 6.59 methoxypropanol 16,98 16,98 16,98 16,98 16,98 16,98 IR-1 0.1 - - - - - IR-2 - 0.1 - - - - IR-3 - - 0.1 - - - IR-4 - - - 0.1 - - IR COMP1 - - - - 0.1 - IR COMP2 - - - - - 0.1 Flexo blue 630 ** 0.03 0.03 0.03 0.03 0.03 0.03 Fluorad FC431 *** 0.14 0.14 0.14 0.14 0.14 0.14 2,3,4-trimethoxy 0.36 0.36 0.36 0.36 0.36 0.36 IR sensitivity (mJ / cm ² ) 100 80 120 80 > 200 > 200

• * Alnovol SPN452 is a 40.5% solution in Dowanol PM (available from Clariant),
• ** triarylmethane dye, available from BASF,
• *** A perfluoroalkyl-containing polymer, obtainable by 3M / 10% by weight solution in methoxypropanol.
• ° BS = reference example

Claims (9)

A heat-sensitive lithographic printing plate precursor comprising a support having a hydrophilic surface and a coating applied to the hydrophilic surface, the coating comprising in sequence a first layer containing an oleophilic, aqueous alkaline-soluble resin, and a second layer comprising capable of preventing penetration of the developer into the first layer in unexposed areas, the second layer containing a water-repellent compound selected from the group consisting of: a polymer having siloxane monomer units and / or perfluoroalkyl monomer units; and a block copolymer or graft copolymer having a poly ( alkylene oxide) or oligo (alkylene oxide) and a polymer or oligomer having siloxane monomer units and / or perfluoroalkyl monomer units, and wherein the alkali solubility of the coating is increased by heating and the coating contains at least one perfluoroalkyl group n contains infrared dye, characterized in that the infrared dye is electrically charged and at least one at least 6 fluorine atoms bearing perfluoroalkyl group is contained in a counterion. A lithographic printing plate precursor according to claim 1, characterized in that the infrared dye further at least contains a covalently bound perfluoroalkyl group. Lithographic printing plate precursor according to one of previous claims, characterized in that the infrared dye is a squarylium dye, a croconate dye, a merocyanine dye, a cyanine dye, an indolizine dye, a pyrilium dye or a metal dithiolin dye is. Lithographic printing plate precursor according to any one of the preceding claims, characterized in that the water-repellent compound is used in an amount between 0.5 and 15 mg / m ² in the coating. Lithographic printing plate precursor according to one of previous claims, characterized in that the second layer is substantially from the water-repellent Compound and the infrared dye is composed. Lithographic printing plate precursor according to one of the preceding claims, characterized in that the infrared dye corresponds to the formula:

in which: -L ¹ - and -L ² - independently of one another denote a divalent linking group, -E ¹ and -E ² independently of one another a neutral, anionic or cationic end group from the group consisting of alkyl, -OH, -H, -Cl , -Br, -F (neutral groups), -SO ₃ -, -SO ₄ -, -PO ₃ ^2- , -PO ₄ ^2- , -COO ^- (anionic groups) and - [NR ^a R ^b R ^c ] ⁺ (cationic group), wherein R ^a , R ^b and R ^c independently represent a hydrogen atom or an alkyl group, -A ¹ - and -A ² - independently of one another -C _v F _2v -, - [(CF ₂ ) ₂ -O] _w -, a long-chain, containing at least four carbon atoms alkyl group or an optionally substituted alkyl group, alkenyl group, aryl group or aralkyl group, wherein p ₁ and p _{2 are} 0 or 1, wherein v and w are 2 or an integer above 2 , -Y ¹ - and -Y ² - independently of one another -CR ⁹ R ¹⁰ -, -S-, -Se-, -NR ¹¹ -, -CH = CH- or -O-, R ¹ to R ¹¹ independently of one another one water each atom, an optionally substituted alkyl group, alkenyl group, aryl group or aralkyl group or a halogen atom, -NO ₂ , -OR ^d , -CO-R ^d , -CO-OR ^d , -O-CO-R ^d , -CO-NR ^d R ^e , -NR ^d R ^e , -NR ^d -CO-R ^e , -NR ^d -CO-OR ^e , -NR ^d -CO-NR ^e R ^f , -SR ^d , -SO-R ^d , -SO ₂ -R ^d , -SO ₂ -OR ^d , -SO ₂ NR ^d R ^e or a perfluoroalkyl group, wherein each of said groups may optionally comprise an end group E defined above as -E ¹ and -E ² and / or two neighboring groups the group consisting of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , Y ¹ and Y ² together form an optionally substituted 5-membered or 6-membered ring, wherein R ^d , R ^e and R ^f independently of one another denote a hydrogen atom or an optionally substituted alkyl group, alkenyl group, aryl group or aralkyl group, Z ¹ and Z ³ independently of one another each represent a hydrogen atom or an alkyl group or together to complete an optionally s ubstituierten 5-membered or 6-membered ring atoms necessary mean z ² consisting represents a substituent selected from the group consisting of a hydrogen atom, a halogen atom and an optionally substituted alkyl group, amino group, arylthio group, alkylthio group, aryloxy group, alkoxy group, barbituric acid group or Thiobarbitursäuregruppe, X is a or more counterions having a total charge opposite to the charge of the dye, and at least one counterion X contains a perfluoroalkyl group containing at least 6 fluorine atoms. Printing plate precursor according to claim 6, characterized in that z ¹ - (CH ₂ ) ₂ - or - (CH ₂ ) ₃ - means. A lithographic printing plate precursor according to claim 7, characterized in that the infrared dye corresponds to one of the following formulas:

in which p ₁ , p ₂ , -L ¹ , -L ² , -A ¹ -, -A ² -, -E ¹ , -E ² , R ⁹ , R ¹⁰ , Z ² and X denote these symbols in Claim 6 have measured significance. Lithographic printing plate precursor according to one of claims 7 and 8, characterized in that the infrared dye corresponds to one of the following formulas:

in which: m is 2 or an integer greater than 2, R ^{14 is} - (CH ₂ ) ₂ -OCO- (CH ₂ ) ₂ - (CF ₂ ) _k -CF ₃ , where k is 2 or an integer greater than 2 , and G is SO 3 ^- , SO 4 ^- or COO ^- means.