DE102004029503A1 - New polymer modified with infra red-absorber (obtained by reaction of a polymer with phenolic groups and/or sulfonamide groups, with a photo-thermal transformation material), useful for the production of radiation-sensitive elements - Google Patents

Abstract

Polymer (I) modified with infra red (IR)-absorber, obtained by reaction of a polymer (a) with phenolic OH groups and/or -SO2NHR groups, with a photo-thermal transformation material (b) which exhibits covalently bound halogen atom (X) that reacts with phenolic OH group or SO2NHR groups under HX splitting and alkaline conditions (where (I) is soluble in aqueous solution and the solubility is not changed by IR radiation), is new. Polymer (I) modified with infra red (IR)-absorber, obtained by reaction of a polymer (a) with phenolic OH groups and/or -SO2NHR groups, in the side chain (where (a) is soluble in aqueous-alkaline solution and the solubility is not changed by IR radiation) with a photo-thermal transformation material (b), which is in a position to absorb a radiation of 750-1300 nm and converts into warmth, where (b) in the molecule exhibits at least covalently bound halogen atom (X), which can react with a phenolic OH group or SO2NHR groups under HX splitting and alkaline conditions (where (I) is soluble in aqueous solution and the solubility is not changed by IR radiation), is new. R : H, alkyl, aryl or aralkyl. Independent claims are included for: (1) radiation-sensitive negatively working element comprising a carrier with hydrophilic surface and a layer (comprising (I)) on the hydrophilic surface of the carrier; (2) radiation-sensitive positively working element comprising a carrier with hydrophilic surface, a first layer (comprising (I)) on the hydrophilic surface of the carrier and a surface layer, which is not soluble in aqueous-alkaline developer or of it penetrable, but it is soluble by IR radiation in aqueous-alkaline developer or of it penetrable; and (3) preparation of an illustrated element, comprising providing radiation-sensitive element; picture-wise illuminating of the element with IR radiation or picture-wise suspending the element with a heat source; and picture-wise developing the illuminated element with an aqueous-alkaline developer.

Description

The The invention relates to polymers modified with IR absorbers, the Manufacture and use for the production of radiation-sensitive Elements, such as e.g. Lithographic printing plate precursor.

The The field of lithographic printing is based on immiscibility of oil and water, being the oily one Material or ink preferably from the image area and the Water or dampening agent preferably adopted from the non-image area becomes. If a properly prepared surface is moistened with water and then applied a printing ink, the background or the takes Non-image area the water and rejects the ink while the Image area takes the ink and repels the water. The printing ink on the image area is then applied to the surface of a material, such as paper, Tissue and the like, transferred, on which the picture should be created. In general, the But first transfer ink to an intermediate material called a blanket which then transfers the ink to the surface of the material which the image should be created; This is called offset lithography.

A often used type of lithographic printing plate precursor (with Printing plate precursor Here is a coated printing plate before exposing and developing denotes) applied to an aluminum-based support, photosensitive coating on. The coating can react to radiation, making the exposed part so soluble will be removed in the development process. Such a Plate is called positive working. Conversely, a Plate referred to as negative working when the exposed part the coating is cured by the radiation. In both cases decreases the remaining image area is ink on or is oleophilic and The non-image area (background) absorbs water or is hydrophilic. The differentiation between image and non-image areas takes place when exposing.

at conventional plates becomes a film that transmits the Contains information on the plate precursor - to ensure a good contact with vacuum - applied. The plate will then with a radiation source, part of which is UV radiation is composed, exposed. If used a positive plate is, the area corresponding to the image on the plate is on so opaque to the film, light does not attack the plate while the non-image area appropriate area on the film is clear and the light transmission on the coating, which is then more soluble is allowed. In the case of a negative plate, the reverse is true to: The area corresponding to the image area on the film is clear while the non-image area is opaque. The coating under the clear film area is hardened by the action of light, while the removed by light unaffected area during development becomes. The photohardened surface a negative plate is therefore oleophilic and takes printing ink on while the Non-image area caused by the action of a developer removed coating, desensitized and therefore is hydrophilic.

Over several Decades of positive-working commercial printing plate precursors distinguished themselves the use of alkali-soluble Phenolic resins and naphthoquinone diazide derivatives from; the illustration was done with UV radiation.

newer Develop developments in the field of lithographic printing plate precursors radiation-sensitive compositions ready for production of directly addressable with laser print form precursors are suitable. The digital imaging information may be used to image the printing form precursor a picture can be used without - as usual with conventional plates - the use of a Films is required.

In The last few years have been reinforced at the development of heat-sensitive Printing plate precursors (often referred to as "thermal plates") worked. The illustration is done here about direct heat or over Radiation (such as IR radiation) emitted by a light-to-heat converter (e.g., IR absorber) in heat is converted.

An example of a positive-working laser-addressable printing form precursor is shown in FIG US 4,708,925 described. The patent describes a lithographic printing plate precursor in which the image-forming layer comprises a phenolic resin and a radiation-sensitive opium salt. As described in the patent, the interaction of the phenolic resin and the opium salt causes the alkali urea solubility of the composition, from which the alkali solubility is restored by photolytic decomposition of the opium salt is provided. The printing form precursor may be used as a precursor to a positive working printing form or as a precursor to a negative working printing form using additional process steps between exposure and development, as more particularly shown in British Patent No. 2,082,339. In the US 4,708,925 The printing form precursors described are intrinsically sensitive to UV radiation and can additionally be made sensitive to visible and infrared radiation.

Another example of a laser addressable printing form precursor which can be used as a positive-working system is shown in FIG US 5,372,907 and US 5,491,046 described. These two patents disclose radiation induced decomposition of a latent Brönsted acid to increase the solubility of the resin matrix upon imagewise exposure. As with the in US 4,708,925 These printing systems can also be used as a negative-working system with additional process steps between imaging and development. In the negative-working printing form precursors, the decomposition by-products are then used to catalyze a crosslinking reaction between resins to insolubilize the layer of irradiated areas, which requires a heating step prior to development. As in US 4,708,925 For example, these printing form precursors are sensitive to UV radiation as a result of the acid-generating materials used.

US 5,658,708 describes positive and negative thermally imageable elements. In the case of the negative-working elements, the coating applied in one step contains, for example, a compound having at least 2 enol ether groups and an alkali-soluble resin having acid groups which can react with the enol ether groups on heating. The drying takes place at a relatively low temperature. In the image-forming step, the coating is intensively heated imagewise, whereby crosslinking occurs which renders the coating insoluble in the developer. In the case of the positive-working elements, the coating additionally contains, for example, an acid generator; the drying takes place at relatively high temperatures, so that the coating of the unimaged element is crosslinked and thus insoluble in the developer. By imagewise irradiation with IR radiation, the coating is then soluble in the developer. The use of acid formers has the disadvantage that the plate is thus sensitive to UV light and thus also daylight (also in the sense of normal room light).

In DE 198 50 181 are described printing plate precursor whose radiation-sensitive layer comprises a polymeric binder, a compound which releases an acid under heat, a photothermal conversion material and a crosslinkable polyfunctional enol ether, the polymeric binder having both protective groups which are cleavable by acid and heat action, as well contains functional groups that allow cross-linking with enol ethers, and wherein the binder is insoluble in aqueous alkaline media having a pH ≤13.5.

In US 5,858,626 A positive-working heat-sensitive lithographic printing plate precursor having a single-layer structure will be described. The heat-sensitive layer contains an IR absorber and a phenolic resin which is either in admixture with or reacted with an o-diazonaphthoquinone derivative.

WHERE 97/39894 A1 describes oleophilic thermosensitive compositions for coatings of Lithographic printing plate precursors, the one soluble in the developer Polymer and a compound that reduces the solubility of the polymer, contain; it is believed that a thermally unstable Complex forms.

WHERE 99/11458 A1 describes single-layer heat-sensitive elements, such as Lithographic printing plate precursors whose thermosensitive Coating is temporarily soluble in the developer by IR irradiation.

In U.S. Patents 6,352,811 B1; 6,352,812 B1; and 6,358,669 B1 each positive-working thermal plates with two-layer structure described. These thermal plates have excellent radiation sensitivity on, their solvent resistance enough but not highest yet Claims.

US 6,506,533 B1 describes polymers with IR-absorbing side chain, which are not soluble in aqueous alkaline developer, but which are soluble by IR radiation in aqueous alkaline developer; their use in lithographic printing plate precursors is also described.

In US 6,124,425 there is described an IR-absorbing polymer comprising IR-absorbing structural units, processibility structural units and thermally-reactive structural units; The polymer is used for laser-imageable coatings.

It Object of the invention, modified with IR absorber polymers to provide when used for the production of heat-sensitive Elements, such as lithographic printing plate precursors, which Solvent resistance improve such elements without the radiation sensitivity losses must be accepted. Another object is the provision of heat-sensitive Elements with improved solvent resistance.

• (a) einem Polymer mit phenolischen OH-Gruppen und/oder -SO₂NHR Gruppen, in denen R unabhängig aus H, Alkyl, Aryl und Aralkyl ausgewählt wird, in der Seitenkette, wobei das Polymer in wässrig-alkalischer Lösung löslich ist und die Löslichkeit durch IR-Strahlung nicht verändert wird, mit
• (b) einem photothermischen Umwandlungsmaterial, das in der Lage ist, Strahlung aus einem Wellenlängenbereich von 750 bis 1300 nm zu absorbieren und in Wärme umzuwandeln, wobei das photothermische Umwandlungsmaterial im Molekül mindestens ein kovalent gebundenes Halogenatom X aufweist, das mit einer phenolischen OH-Gruppe oder -SO₂NHR Gruppe unter HX-Abspaltung reagieren kann, unter alkalischen Bedingungen, wobei das modifizierte Polymer in wässrig-alkalischer Lösung löslich ist und sich die Löslichkeit durch IR-Strahlung nicht verändert.

The first object is achieved by an IR absorber-modified polymer obtainable by reacting

• (a) a polymer having phenolic OH groups and / or -SO ₂ NHR groups in which R is independently selected from H, alkyl, aryl and aralkyl in the side chain, wherein the polymer is soluble in aqueous alkaline solution and the Solubility due to IR radiation is not changed, with
• (b) a photothermal conversion material capable of absorbing radiation from a wavelength range of 750 to 1300 nm and converting it to heat, the photothermal conversion material in the molecule having at least one covalently bonded halogen atom X having a phenolic OH group or -SO ₂ NHR group can react under HX cleavage, under alkaline conditions, wherein the modified polymer is soluble in aqueous-alkaline solution and the solubility does not change by IR radiation.

1 Figure 12 shows the change in color density over time upon exposure of blanket cleaning solution to the coating of Example 1 and Comparative Examples 1 and 2.

Unless otherwise defined, in the context of this invention an alkyl radical is understood to mean a straight-chain, branched or cyclic saturated hydrocarbon radical which preferably has 1 to 18 carbon atoms, more preferably 1 to 10 carbon atoms, and particularly preferably 1 to 6 carbon atoms. The alkyl radical may optionally have one or more substituents (preferably 0 or 1 substituent), for example selected from halogen atoms (fluorine, chlorine, bromine, iodine), CN, NO ₂ , NR ' ₂ , COOR' and OR '(R' independently represents a hydrogen atom or an alkyl radical). The above definition also applies to the alkyl moiety of an aralkyl group and an alkoxy group.

Unless defined otherwise, an aryl radical in the context of this invention is understood as meaning an aromatic carbocyclic radical having one or more fused rings, which preferably has 5 to 14 carbon atoms. The aryl radical may optionally have one or more substituents (preferably 0 to 3), for example selected from halogen atoms, alkyl radicals, alkoxy radicals, CN, NO ₂ , NR ' ₂ , COOR' and OR '(wherein each R' is independently selected from hydrogen and Alkyl is selected). The above definition also applies to the aryl unit of an aralkyl radical. Preferred examples are a phenyl group and a naphthyl group, which may be optionally substituted.

in the This invention is under a fused ring or Ring system understood a ring connected to the ring to which it condenses is, has two carbon atoms in common.

The photothermal conversion material (also referred to as "IR absorber" for short) is capable of absorbing and converting IR radiation into heat, and the chemical structure of the IR absorber is not particularly limited as long as it is capable of absorbing To convert radiation into heat and having at least one halogen atom X capable of reacting with a phenolic OH group or -SO ₂ NHR group with HX cleavage It is preferred that the IR absorber in the range of preferably 750 to 1300 nm is an essential Absorption is preferred, preferably having an absorption maximum there, IR absorbers having an absorption maximum in the range from 800 to 1100 nm are preferred, and it is further preferred that the IR absorber does not absorb or substantially absorb radiation in the UV range Absorbers are made, for example, of phthalocyanine pigments / dyes and pigments / dyes of polythiophene-squarylium, thiazolium-croconate, merocyanine, cyanine, indol Zinc, pyrylium or Metalldithiolinklasse, more preferably selected from the cyanine class, but must have at least one covalently bonded halogen atom. Suitable IR absorbers are, for example, those of the compounds mentioned in Table 1 of WO 00/29214 which have a covalently bonded halogen atom.

wobei
jedes Z¹ unabhängig für S, O, NR^a oder C(Alkyl)₂ steht;
jedes R' unabhängig einen Alkylrest, einen Alkylsulfonatrest oder einen Alkylammoniumrest bedeutet;
R'' für ein Halogenatom, SR^a, OR^a, SO₂R^a oder NR^a ₂ steht;
jedes R''' unabhängig für ein Wasserstoffatom, einen Alkylrest, -COOR^a, -OR^a, -SR^a, -NR^a ₂ oder ein Halogenatom steht; R''' kann auch ein benzokondensierter Ring sein;
A^– für ein Anion steht;
--- für einen gegebenenfalls vorhandenen carbocyclischen Fünf- oder Sechsring steht;
R^a für ein Wasserstoffatom, einen Alkyl- oder Arylrest steht;
jedes b unabhängig 0, 1, 2 oder 3 sein kann,
mit der Maßgabe, dass mindestens einer der Reste R'' und R''' ein Halogenatom ist, eingesetzt.According to one embodiment, a cyanine dye of the formula (I)

in which
each Z ^{1 is} independently S, O, NR ^a or C (alkyl) ₂ ;
each R 'independently represents an alkyl group, an alkylsulfonate residue or an alkylammonium residue;
R '' is a halogen atom, SR ^a , OR ^a , SO ₂ R ^a or NR ^a ₂ ;
each R '''independently represents a hydrogen atom, an alkyl group, -COOR ^a , -OR ^a , -SR ^a , -NR ^a ₂ or a halogen atom; R '''may also be a benzo-fused ring;
A ^{- stands} for an anion;
--- represents an optionally present carbocyclic five- or six-membered ring;
R ^{a represents} a hydrogen atom, an alkyl or aryl radical;
each b can independently be 0, 1, 2 or 3,
with the proviso that at least one of R '' and R '''is a halogen atom used.

When R 'is an alkylsulfonate radical, an internal salt can form so that no anion A ^{- is} necessary. When R 'is an alkylammonium radical, a second counterion which is the same as or different from A ^- is necessary.
Z ¹ is preferably a C (alkyl) ₂ group.
R 'is preferably an alkyl radical having 1 to 4 carbon atoms.
R '' is preferably a halogen atom or SR ^a , wherein a radical R '''must be a halogen atom when R''is SR ^a .
each R '''is preferably a hydrogen atom or halogen atom, where R''must be a halogen atom when each R''' is H.
R ^a is preferably an optionally substituted phenyl radical or an optionally substituted heteroaromatic radical.

The dashed line preferably represents the remainder of a ring of 5 or 6 C atoms. The counterion A ^- is preferably a chloride ion, trifluoromethylsulfonate or a tosylate anion.

Of the IR dyes of the formula (III), those having a symmetrical structure are particularly preferable. Examples of particularly preferred dyes are:
2- [2- [2-chloro-3- [2- (1,3-dihydro-1,3,3-trimethyl-2H-benzo [e] indol-2-ylidene) ethylidene] -1-cyclohexene -l-yl] -ethenyl] -1,3,3-trimethyl-1H-benzo [e] -indolium tosylate and
2- [2- [2-chloro-3- [2-ethyl- (3H-benzthiazole-2-ylidene) ethylidene] -1-cyclohexen-l-yl] ethenyl] -3-ethyl-benzthiazolium-tosylate.

Further IR absorbers suitable for the present invention are the following compounds:

Besides, those can IR absorbers shown in Table 1 of WO 00/29214 and a contain covalently bonded halogen atom; be used.

wobei Y¹ ein gegebenenfalls substituierter aliphatischer, gegebenenfalls substituierter aromatischer oder gegebenenfalls substituierter heterocyclischer Spacer oder eine Kombination von zwei oder mehreren ist,
jedes R unabhängig ausgewählt wird aus einem Alkylrest, einem Alkoxyrest und einem Halogenatom,
m eine ganze Zahl von 1 bis 5 ist,
n 0 oder eine ganze Zahl von 1 bis 4 ist,
und m + n ≤ 5 ist,
oder ein Homo- oder Copolymer, das sowohl phenolische OH-Gruppen als auch -SO₂NHR-Gruppen in den Seitenketten aufweist.The starting polymer is a homo- or co-polymer with -SO ₂ NHR groups in the side chains or a homo- or copolymer with phenolic OH groups in the side chains, which contains the following structural unit (II)

wherein Y ^{1 is} an optionally substituted aliphatic, optionally substituted aromatic or optionally substituted heterocyclic spacer or a combination of two or more,
each R is independently selected from an alkyl group, an alkoxy group and a halogen atom,
m is an integer from 1 to 5,
n is 0 or an integer from 1 to 4,
and m + n ≤ 5,
or a homo- or copolymer having both phenolic OH groups and -SO ₂ NHR groups in the side chains.

By "heterocyclic spacer" in the context of this invention is meant a saturated, unsaturated or aromatic divalent radical in which one or more ring carbon atoms are substituted by heteroatoms selected from O, S, N and NR ¹ (wherein R ^{1 is} H, alkyl, aryl and Aralkyl is selected) are replaced.

In the context of this invention, "aliphatic spacer" is understood to mean a saturated or (mono- or polyunsaturated) unsaturated chain-like divalent radical, where the chain may also contain branches, and the carbon chain may be substituted by heteroatoms selected from O, S, NR ¹ , N be interrupted.

wobei R, m und n wie vorstehend definiert sind.In one embodiment, the starting polymer is a polyvinyl acetal containing the following units (A), (B) and (C)

wherein R, m and n are as defined above.

wobei R, m und n wie vorstehend definiert sind.In another embodiment, the starting polymer is a maleimide unit polymer of the following structure (D)

wherein R, m and n are as defined above.

Further suitable starting polymers are polyvinylphenols and copolymers from that.

Another group of polymers which can be used as the starting polymer are copolymers containing from 1 to 90 mol% of a sulfonamide monomer unit, in particular N- (p-aminosulfonylphenyl) methacrylamide, N- (mAminosulfonylphenol) methacrylamide, N- (o-aminosulfonylphenyl) methacrylamide and / or corresponding acrylamides. Suitable polymers containing a sulfonamide group in the side group, processes for their preparation, and suitable monomers are disclosed in U.S. Patent Nos. 5,429,866, 4,329,859, 4,329,859, 4,329,859, and 5,305,347 US 5,141,838 B described. Particularly suitable polymers include (1) a sulfonamide monomer unit, especially N- (p-aminosulfonylphenyl) methacrylamide, (2) acrylonitrile and / or methacrylonitrile, and (3) methyl methacrylate and / or methyl acrylate. Some of these copolymers are available under the name PU copolymers from Kokusan Chemical, Gumma, Japan.

In addition, polyacrylates containing structural units of the following formula (IIa) and / or (IIb) may be used: - [CH ₂ -CH (CO-X ¹ -R ^a -SO ₂ NH-R ^b )] - (IIa) - [CH ₂ -CH (CO-X ¹ -R ^a -NHSO ₂ -R ^d )] - (IIb) in which
Each X ¹ represents O or NR ^c ;
R ^a each (preferably C ₁ -C ₁₂₎ represents a substituted or unsubstituted Alkandiylest, Cycloalkandiylrest (preferably C ₆ -C ₁₂₎ arylene group (preferably C ₆ -C ₁₂₎ or Aralkandiylrest (preferably C ₇ -C _14);
R ^b and R ^c each independently represent a hydrogen atom or a substituted or unsubstituted alkyl group (preferably C ₁ -C ₁₂ ); Cycloalkyl (preferably C ₆ -C ₁₂ ), aryl (preferably C ₆ -C ₁₂ ) or aralkyl (preferably C ₇ -C ₁₄ ); and
R ^d represents a substituted or unsubstituted alkyl group (preferably C ₁ -C _12), cycloalkyl (preferably C ₆ -C _12), aryl (preferably C ₆ -C ₁₂₎ or aralkyl (preferably C ₇ -C _14).

Such Polyacrylates and starting monomers and comonomers for their preparation are detailed in EP-A-0 544 264 (pages 3 to 5).

To the polyacrylates of the formula (IIa) and (IIb) analogous polymethacrylates can also be used.

wobei
X² ein substituierter oder unsubstituierter Alkandiylest (vorzugsweise C₁-C₁₂), Cycloalkandiylrest (vorzugsweise C₆-C₁₂), Arylenrest (vorzugsweise C₆-C₁₂) oder Aralkandiylrest (vorzugsweise C₇-C₁₄) ist, und
X³ ein substituierter oder unsubstituierter Arylenrest (vorzugsweise C₆-C₁₂) ist.Also, polyacrylates having pendant sulfonamide groups which additionally contain a urea moiety in the side chains can be used. Such polyacrylates are described, for example, in EP-A-0 737 896 and have the following structural unit (IIc)

in which
X ^{2 is} a substituted or unsubstituted alkanediyl radical (preferably C ₁ -C ₁₂ ), cycloalkanediyl radical (preferably ^two C ₆ -C ₁₂ ), arylene radical (preferably C ₆ -C ₁₂ ) or aralkanediyl radical (preferably C ₇ -C ₁₄ ), and
X ^{3 is} a substituted or unsubstituted arylene radical (preferably C ₆ -C ₁₂ ).

To The polyacrylates of the formula (IIc) analogous polymethacrylates can also be used.

The Reaction of starting polymer (a) and IR absorber (b) takes place at Room temperature or elevated Temperature, e.g. at a temperature of 20 ° C to 90 ° C, preferably at 30 ° C to 60 ° C.

The Reaction takes place in the presence of an alkali reagent, e.g. one Alkali metal hydroxides or alkaline earth metal hydroxides. According to one embodiment For example, an alkaline reagent is used together with an elevated temperature (e.g., 40 ° C to 60 ° C).

The Reaction takes place in a suitable solvent for the starting polymer instead, in which the IR absorber dissolves at least partially. suitable solvent are e.g. Alcohols, alcohol ethers, ketones, N-methylpyrrolidinone and Mixtures thereof.

The Reaction time can vary within a wide range, e.g. from half an hour to 24 hours.

The modified polymer is isolated by precipitation and filtration and subsequently dried. As precipitant For example, water, water acidified with 0.01 to 0.1 wt.% Acid, such as. hydrochloric acid or p-toluenesulfonic acid, or organic solvents, in which the modified polymer is insoluble in question. The drying is preferably carried out at an elevated temperature of 30-80 ° C, but can even at room temperature under vacuum.

The modified according to the invention Polymer can e.g. for the production of radiation-sensitive elements used, such as lithographic printing plate precursors and Photomasks.

Especially are the modified invention Polymers for thermosensitive Suitable elements. By using the modified invention Polymers in radiation-sensitive coatings can increase solvent resistance these coatings are significantly improved. In particular are the modified invention Polymers for the coating of heat-sensitive elements, such as lithographic printing plate precursors, suitable; they can do it both in negative-working single-layer elements as well be used in positive working two-layer elements.

• (i) mindestens eine Verbindung, die bei Wärmeeinwirkung eine Säure bildet (im Folgenden auch als „latente Brönstedsäure bezeichnet), und
• (ii) eine durch Säure vernetzbare Komponente (im Folgenden auch als „Vernetzungsmittel" bezeichnet) oder ein Gemisch davon und gegebenenfalls
• (iii) ein Bindemittelharz oder ein Gemisch davon.

In the case of the negative-working single-layer elements according to the invention, there is a radiation-sensitive layer on the hydrophilic surface of the support which becomes insoluble or impermeable by IR irradiation in the aqueous alkaline developer and which contains one or more modified polymers according to the invention. Preferably, the layer also contains

• (i) at least one compound which forms an acid upon exposure to heat (hereinafter also referred to as latent Bronsted acid), and
• (ii) an acid-crosslinkable component (hereinafter also referred to as "crosslinking agent") or a mixture thereof and optionally
• (iii) a binder resin or a mixture thereof.

When latent Brönsted acid come ionic and nonionic in question. Examples of ionic latent Bronsted acids include opium salts, especially iodonium, sulfonium, oxysulfoxonium, oxysulfonium, Phosphonium, selenonium, telluronium, diazonium and arsonium salts one. Specific examples are diphenyliodonium hexafluorophosphate, Triphenylsulfonium hexafluoroantimonate, phenylmethyl-ortho-cyanobenzylsulfonium trifluoromethanesulfonate and 2-methoxy-4-aminophenyl diazonium hexafluorophosphate.

Examples of nonionic latent Bronsted acids are RCH ₂ X, RCHX ₂ , RCX ₃ , R (CH ₂ X) ₂ and R (CH ₂ X) ₃ , where X is Cl, Br, F or CF ₃ SO ₃ and R is an aromatic , aliphatic or araliphatic radical.

Suitable ionic latent Bronsted acids are also those of the formula X ^⊕ R ^1a R ^1b R ^1c R ^1d W ^⊝ where X is iodine, R ^1a and R ^{1d are lone} pairs and R ^1a and R ^{1b are} aryl radicals or substituted aryl radicals,
when X is S or Se, R ^{1d is} a lone pair of electrons, and R ^1a , R ^1b , R ^{1c are} independently selected from aryl radicals, substituted aryl radicals, an aliphatic radical or substituted aliphatic radical,
when X is P or As, R ^{1d may be} aryl, substituted aryl, aliphatic or substituted aliphatic, and
where W is selected from BF ₄ , CF ₃ SO ₃ , SbF ₆ , CCl ₃ CO ₂ , ClO ₄ , AsF ₆ or PF ₆ .

Also suitable are C ₁ -C ₅ -alkyl sulfonates, arylsulfonates (eg benzoin tosylate, 2-hydroxymethylbenzointosylate and 2,6-dinitrobenzyl tosylate) and NC ₁ -C ₅ -alkyl sulfonylsulfonamides (eg N-methanesulfonyl-p-toluenesulfonamide and N-methanesulfonyl-2,4-dimethylbenzenesulfonamide).

Suitable specific opium compounds are described in detail, for example US 5,965,319 with the formulas (I) to (III) listed.

The latent Brönsted acids preferably in an amount of 0.5 to 50% by weight, especially preferably 3 to 20% by weight, based on the dry layer weight, used.

The crosslinking agent may be, for example, in the resin selected from resole resins, C ₁ -C ₅ alkoxymethylmelamines, C ₁ -C ₅ alkoxymethyl glycoluril resins, poly (C ₁ -C ₅ alkoxymethylstyrenes) and poly (C ₁ -C _5- alkoxymethylacrylamides), epoxidized novolak resins and urea resins. In particular, compounds are usable as crosslinking agents having in a molecule at least 2 groups selected from hydroxymethyl, alkoxymethyl, epoxy and vinyl ether groups attached to a benzene ring; Preferred are phenol derivatives having at least 2 groups selected from hydroxymethyl and alkoxymethyl groups attached to a benzene ring, 3 to 5 benzene rings, and a molecular weight of 1200 or less, as described in U.S. Pat US 5,965,319 listed in columns 31 to 37.

The Crosslinking agent is preferably in an amount of 5 to 90 wt.%, Based on the dry layer weight, particularly preferred 10 to 60 wt. Used.

As the binder in the radiation-sensitive layer, the modified polymer of the present invention can function. However, one or more further binders may optionally also be present, for example selected from polymers having an alkali-soluble group, such as novolaks, acetone-pyrogallol resin, polyhydroxystyrenes and hydroxystyrene-N-substituted maleimide copolymers, as in US 5,965,319 listed as component (C), or polymers as in US 5,919,601 called binder resin.

The Binder is preferably in an amount of 0 to 90 % By weight, based on the dry layer weight, particularly preferred 5 to 60 wt.% Used.

In principle, known heat-sensitive elements with a single-layer structure, such as those in US 5,919,601 . US 5,965,319 . US 5,371,907 and WO 00/17711 A1, are modified by additional use of the modified polymer according to the invention in the coating. Preferably, the modified polymer is used in a single-layer structure in an amount of 5 to 80 wt.%, Based on the dry layer weight, particularly preferably 20 to 60 wt.%.

at the invention positive working two-layered elements is located on the hydrophilic surface of the carrier a first layer that is in aqueous-alkaline Developer soluble is, their solubility does not change by IR irradiation and a modified invention Contains polymer; on the first layer is an aqueous-alkaline developer insoluble Cover layer which is soluble in the developer by IR irradiation or becomes permeable by the developer.

• (a) Es wird ein in stark alkalischem wässrigen Entwickler (pH > 11) unlösliches Polymer verwendet, das durch IR-Bestrahlung im Entwickler löslich oder von diesem durchdringbar wird; solche Systeme sind z.B. in US 6,352,812 beschrieben.
• (b) Es wird ein in stark alkalischem wässrigen Entwickler (pH > 11) lösliches Polymer verwendet, dessen Löslichkeit durch einen gleichzeitig vorhandenen Löslichkeitsinhibitor so stark reduziert wird, dass die Schicht unter Entwicklungsbedingungen nicht lösbar oder durchdringbar ist; durch IR-Bestrahlung wird die Wechselwirkung zwischen Polymer und Inhibitor so geschwächt, dass die Schicht in den bestrahlten (erwärmten) Bereichen im Entwickler löslich oder durchdringbar wird. Solche Systeme sind z.B. in US 6,352,811 und US 6,358,669 beschrieben. Es ist nicht erforderlich, dass Polymer und Löslichkeitsinhibitor als zwei getrennte Verbindungen vorliegen, sondern es können auch Polymere eingesetzt werden, die gleichzeitig eine Löslichkeitsinhibitorfunktion aufweisen, wie z.B. die in US 2002/0,150,833 A1, US 6,320,018 B und US 6,537,735 beschriebenen funktionalisierten Harze, wie z.B. funktionalisierte Novolake.
• (c) Es wird ein in wässrig-alkalischem Entwickler mit pH < 11 unlösliches (bei pH > 11 aber lösliches) Polymer verwendet, das durch IR-Bestrahlung in einem solchen Entwickler mit pH < 11 löslich wird, und die Entwicklung des bestrahlten Elements wird mit einem alkalischen Entwickler mit pH < 11 vorgenommen. Ein derartiges System ist zum Beispiel in WO 02/14071 beschrieben.

For the topcoat, known principles can be used:

• (A) A polymer which is insoluble in strongly alkaline aqueous developer (pH> 11) and which becomes soluble in or permeable to the developer by IR irradiation is used; such systems are eg in US 6,352,812 described.
• (b) A polymer which is soluble in a strongly alkaline aqueous developer (pH> 11) and whose solubility is so greatly reduced by a co-existing solubility inhibitor that the layer is not soluble or penetrable under development conditions is used; IR irradiation weakens the interaction between polymer and inhibitor so that the layer becomes soluble or penetrable in the exposed (heated) areas in the developer. Such systems are eg in US 6,352,811 and US 6,358,669 described. It is not necessary for the polymer and solubility inhibitor to be present as two separate compounds, but it is also possible to use polymers which simultaneously have a solubility inhibitor function, such as those described in US 2002 / 0,150,833 A1, for example. US 6,320,018 B and US 6,537,735 described functionalized resins, such as functionalized novolacs.
• (c) A polymer which is insoluble in aqueous alkaline developer of pH <11 (but soluble at pH> 11) and which becomes soluble by IR irradiation in such a developer of pH <11, becomes the development of the irradiated element with an alkaline developer with pH <11 made. Such a system is described, for example, in WO 02/14071.

For a covering layer of the above type (a), (meth) acrylic polymers and copolymers, polystyrene, styrene- (meth) acrylic acid copolymers, polyesters, polyamides, polyureas, polyurethanes, nitrocelluloses, epoxy resins and combinations thereof may be used, provided that they are in alkaline Developers are insoluble at pH> 11, by IR radiation but soluble in the developer or from this penetrable. The polymer for a cover layer of type (a) is applied in an amount such that preferably a cover layer with a dry layer weight of 0.1 to 1.5 g / m ² , more preferably 0.2 to 0.9 g / m ² is obtained.

For a topcoat of the above type (b) are preferably polymers and copolymers used with phenolic OH groups, that is phenolic resins. As appropriate Phenolic resins are e.g. Novolacs, resols, acrylic resins with phenolic To name side chains and polyvinylphenol resins, of which novolaks especially are preferred.

For the present Invention suitable novolak resins are condensation products of suitable phenols, for. As phenol itself, substituted C-alkyl Phenols (including Cresols, xylenols, p-tert-butylphenol, p-phenylphenol and nonylphenols) and diphenols (eg bisphenol-A), with suitable aldehydes such as formaldehyde, Acetaldehyde, propionaldehyde and furfuraldehyde. The type of catalyst and the molar ratio the reactants determine the molecular structure and thus the physical Properties of the resin. An aldehyde-phenol ratio from about 0.5: 1 to 1: 1, preferably 0.5: 1 to 0.8: 1 and an acid catalyst are used to prepare those phenolic resins known as "novolacs" and have a thermoplastic character. As used in the application here, The term "novolak resin" but also known as "Resole" phenolic resins include those at higher levels Aldehyde phenol ratios and basic catalysts.

When The solubility inhibitor (also referred to as "insolubilizer") present in the topcoat of type (b) may be Insolubilizers already described in the prior art can be used or others.

suitable insolubilizing are z. As described in WO 98/42507 and EP-A 0 823 327 non-photosensitive Compounds having functional groups which react with the phenolic OH groups of novolak resins a hydrogen bond can enter. Suitable functional groups in WO 98/42507 are sulfone, Sulfoxide, thione, phosphine oxide, nitrile, imide, amide, thiol, Ether, alcohol, urea, nitroso, azo, azoxy, nitro groups, Called halogens and especially keto groups. As examples of suitable Compounds are xanthone, flavanone, flavone, 2,3-diphenyl-1-indenone, Pyron, thiopyron and 1 '- (2'-acetonaphthonyl) benzoate called.

In WO 99/01795 are used as insolubilizers Polymers with special functional groups Q used which preferably no Diazidgruppierung and no acid group or acid generating group contained and according to one preferred embodiment Q is selected from amino, monoalkylamino, dialkylamino, amido, monoalkylamido, Dialkylamido groups, fluorine atoms, chlorine atoms, carbonyl, sulfinyl or sulfonyl groups. These polymeric insolubilizers can also used in the present invention.

Also the insolubilizers described in WO 99/01796, in this case Compounds with diazide units can be used in the present invention be used.

Another group of insolubilizers suitable for this invention is described in WO 97/39894. It is z. Nitrogen-containing compounds wherein at least one nitrogen atom is quaternized and is part of a heterocyclic ring; Examples are z. Quinolinium compounds, benzothiazolium compounds and pyridinium compounds, and in particular cationic trimethylmethane dyes such as Victoria Blue (CI Basic Blue 7), Crystal Violet (CI Basic Violet 3) and Ethyl Violet (CI Basic Violet 4). Furthermore, compounds having a carbonyl function such as N- (4-bromobutyl) phthalimide, benzophenone and phenanthrenequinone are mentioned. Also suitable compounds of the formula Q ₁ -S (O) _n -Q ₂ (with Q ₁ = optionally substituted phenyl or alkyl radical, n = 0.1 or 2, Q ₂ = halogen atom or alkoxy radical), acridine orange base and ferrocenium compounds in question ,

Provided the possibly existing IR absorbers mentioned in WO 97/39894 Contain structural elements, they also act as insolubilizers.

Also those described in US-2002-0,150,833 A1 and US-6,320,018 B functionalized novolaks can in the heat-sensitive invention Elements are used. These novolaks contain substituents, which is a two- or four-center hydrogen bond (preferably 4-center H-bond) between the polymer molecules enable. This will be the solubility of the underlying novolak in an aqueous alkaline developer also degraded. By heating become such hydrogen bonds destroyed and the original one solubility of the novolak restored. If such a functionalized Novolac is used he the function of component (i) and (ii) the heat-sensitive Composition, so the extra Use of novolak without appropriate functional groups and / or an aforementioned insolubilizing not required, but also not excluded.

wobei die Reste R¹ und R² unabhängig voneinander aus einem Wasserstoffatom und einem cyclischen oder geraden oder verzweigten, gesättigten oder ungesättigten Kohlenwasserstoffrest mit vorzugsweise 1 bis 22 Kohlenstoffatomen ausgewählt werden (vorzugsweise Wasserstoff und C₁-C₄-Alkyl), R³ ein phenolischer Rest ist, der sich von einem Novolak R³(OH)_p ableitet, Y ein zweiwertiger cyclischer oder gerader oder verzweigter, gesättigter oder ungesättigter Kohlenwasserstoffrest mit vorzugsweise 1 bis 22 Kohlenstoffatomen ist, der sich von einem Diisocyanat der Formel Y(NCO)₂ (z.B. Isophoron-Diisocyanat, Toluol-1,2-diisocyanat, 3-Isocyanatomethyl-1-methylcyclo-hexylisocyanat) ableitet, m mindestens 1 und p1 oder 2 ist.The functionalized novolaks contain at least one covalently bonded moiety and at least one non-covalently bound moiety, which non-covalent bond is thermally unstable; these novolaks have a 2 or 4-center hydrogen bond in substantially every non-covalently attached moiety. A preferred group of such functionalized novolaks which can be used as a novolak with simultaneous insolubilization function can be described by the following formula (III):

wherein the radicals R ¹ and R ^{2 are} independently selected from a hydrogen atom and a cyclic or straight or branched, saturated or unsaturated hydrocarbon radical preferably having 1 to 22 carbon atoms (preferably hydrogen and C ₁ -C ₄ alkyl), R ^{3 is} a phenolic Is a radical derived from a novolak R ³ (OH) _p , Y is a divalent cyclic or straight or branched, saturated or unsaturated hydrocarbon radical preferably having 1 to 22 carbon atoms, which is derived from a diisocyanate of the formula Y (NCO) ₂ ( eg isophorone diisocyanate, toluene-1,2-diisocyanate, 3-isocyanatomethyl-1-methylcyclohexylisocyanate), m is at least 1 and p1 or 2.

The Preparation of Functionalized Novolacs of Formula III is US-2002-0,150,833 A1.

Another class of suitable functionalized resins, such as functionalized phenolic resins, and especially functionalized novolacs, is disclosed in U.S. Pat US 6,537,735 B disclosed. While the unfunctionalized resin is soluble in aqueous alkaline developer, the functionalized resin is insoluble in the developer but becomes soluble in the developer by heat (e.g., generated by IR radiation). Preferably, the non-functionalized resin has OH or SH groups which have been at least partially converted to covalently bonded functional groups Q in the functionalized resin; Preferably, the functional groups Q are generated by esterification reaction of the OH groups and are preferably selected from -O-SO ₂ -Tolyl, -O-Dansyl, -O-SO ₂ -Thienyl, -O-SO ₂ -naphthyl and -O- CO-phenyl. The ratio of functional groups Q to OH groups is preferably 1: 100 to 1: 2, more preferably 1:50 to 1: 3. As non-functionalized resins, there may be used, for example, the above-described novolak resins, resole resins, acrylic resins having phenolic side chains and hydroxystyrenes. A particularly preferred functionalized resin of this class is a phenolic resin (preferably a novolak) partially (eg, 10-20%) esterified with toluenesulfonic acid or sulfonic acid chloride; however, in the present invention everyone else in US 6,537,735 described functionalized resins are used.

Although all the above-mentioned insolubilizers can be used in the heat-sensitive coating of the present invention, the following are preferable:
Cyanine dyes, triarylmethane dyes, quinolinium compounds, above insolubilizers with ketone group (s) and above insolubilizers with sulfone group (s) and functionalized novolacs. The cyanine dyes, triarylmethane dyes, quinolinium compounds, ketones and sulfones can be used as low molecular weight substances or in polymer-bound form.

In the heat-sensitive invention Elements can be a single insolubilizer or mixtures of two or more compounds.

The Amount of insolubilizer (s) is not particularly limited as long as the solubility of the novolak in watery alkaline developer is reduced. However, a solubility reduction must be to such an extent done that when exposed to an aqueous alkaline developer the heated ones Regions of the layer are detached much faster than the unheated areas.

Independently of, whether the insolubilizer also acts as an IR absorber is the amount preferably at least 0.1% by weight, based on the dry layer weight, more preferably at least 0.5% by weight, more preferably at least 2 wt .-% and particularly preferably at least 5 wt .-%. Preferably not more than 40% by weight, more preferably not more than 25 % By weight used.

The soluble Polymer is preferably used in cover layers of the above type (b) in an amount of 60 to 99% by weight, based on the dry layer weight the topcoat, more preferably 80 to 98% by weight.

For a topcoat of the above type (c) Polymers with phenolic OH groups or active amide groups (NH). For cover layers of type (c) is not an insolubilizer present, and the polymers with phenolic OH groups allowed it is not a functionalized novolak with the possibility to multi-center hydrogen bonds act.

Both the radiation-sensitive layer in the single-layer elements and the lower layer and / or the cover layer in the two-layer elements may optionally contain further additives which may be added to the coating solution used for the production of the respective layer:
The coating solutions used may also contain dyes or pigments which have a high absorption in the visible spectral range to increase the color contrast ("contrast dyes and pigments") .Suitable are, in particular, those which dissolve well in the solvent or solvent mixture used for coating or Suitable contrasting dyes include, but are not limited to, rhodamine dyes, triarylmethane dyes such as Victoria Blue R and Vikoriarein Blue BO, crystal violet and methyl violet, anthraquinone pigments, azo pigments, and phthalocyanine dyes and pigments, respectively.

In addition, the coating solutions surfactants Agents (e.g., anionic, cationic, amphoteric or nonionic Surfactants or mixtures thereof). Suitable examples are fluorine-containing polymers, polymers with ethylene oxide and / or propylene oxide groups, Sorbitol tristearate and alkyl di (aminoethyl) glycine. Their amount is preferably 0 to 10 wt.%, Based on the solids content of the first coating solution, especially preferably 0.2 to 5 wt.%.

In addition, the coating solutions Print-out dyes, such as crystal violet lactone or photochromic Dyes (e.g., spiropyranes, etc.). Their amount is preferably 0 to 15 wt.%, Based on the solids content of the first coating solution, especially preferably 0.5 to 5 wt.%.

Of Further can Leveling agents may be present in the coating solutions, such as Poly (glycol) ether modified siloxanes; their amount is preferably 0 to 1 wt.%, Based on the solids content of the first coating solution.

Of course you can too other coating aids may be present.

Since the modified polymer is prepared by reacting a suitable poly as described above Mers was obtained with a suitable IR absorber, it is not necessary that in addition an IR absorber is added to the coating solutions; However, it is within the scope of the invention possible to use an additional IR absorber. The optional additional IR absorber may be present in two-layer elements in the lower layer, in the upper layer, or both.

The modified polymer is in two-layer imageable elements in the lower layer, preferably in an amount of 5 to 100 Wt.%, Particularly preferably 50 to 100 wt.%, Based on the dry layer weight, in front.

at The preparation of printing plate precursors is preferred as the carrier a dimensionally stable plate-shaped or foil-shaped Material used. As such a dimensionally stable plate or film material is preferably used that already previously as a carrier for printing forms has been used. Examples of such a carrier include paper, Paper made with plastics (such as polyethylene, polypropylene, polystyrene) coated, a metal plate or foil, e.g. aluminum (including Aluminum alloys), zinc and copper plates, plastic films from, for example, cellulose diacetate, cellulose triacetate, cellulose propionate, Cellulose acetate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, Polystyrene, polypropylene, polycarbonate and polyvinyl acetate, and a laminate of paper or a plastic film and one of the above Metals or a paper / plastic film that metallizes by vapor deposition has been. Among these carriers For example, an aluminum plate or foil is particularly preferred since it remarkably dimensionally stable and is cheap, thermally stable and also has excellent adhesion the coating shows. Furthermore a composite foil can be used, in which an aluminum foil is laminated to a polyethylene terephthalate film.

One Metal support, in particular an aluminum support, is preferably a surface treatment, for example a roughening by brushing in the dry state, or brushes with abrasive suspensions or by electrochemical means, e.g. with a hydrochloric acid electrolyte, and optionally anodic oxidation.

In addition, can to improve the hydrophilic properties of the surface of the roughened and optionally anodized in sulfuric or phosphoric acid metal support this post-treatment with an aqueous solution of e.g. Sodium silicate, Calcium zirconium fluoride, polyvinyl phosphonic acid or phosphoric acid subjected become. In the context of this invention, the term "carrier" also includes an optional one pretreated supports, the e.g. having a hydrophilizing layer on the surface.

The Details of the o.g. Substrate pretreatment are well known to those skilled in the art.

in the By the term of this invention is meant by the notation "(meth) acrylate" both "acrylate" and "methacrylate"; analog applies to "(meth) acrylic acid".

in the For the purposes of this invention, a polymer, e.g. a novolac, as in aqueous alkaline developer soluble when 1 g or more at room temperature in 100 ml Solve developers.

Production Example 1

1. Preparation of Polymer 1A

68.75 g Mowiol ^® 10/98 (polyvinyl alcohol) was dissolved at 60 ° C under a nitrogen atmosphere in 440 ml DMSO. Subsequently, 6.75 ml of concentrated hydrochloric acid (32%) were added, followed by 69.97 g of 4-hydroxybenzaldehyde. After stirring at 60 ° C for 2 hours, 500 ml of ethanol was added. The polyvinyl acetal with phenolic side groups was precipitated in a mixture of 4.5 l of H ₂ O and 1.5 l of ice with stirring, filtered off and dried at 40 ° C in vacuo.

2. Preparation of Polymer 1B

To a solution of 5 g of Polymer 1A in 50 ml of a solvent mixture of methyl glycol, methanol and H ₂ O (55/35/10 by volume) was added 0.048 g of NaOH followed by 0.882 g of IR Trump dye. The solution was heated at 80 ° C for 60 minutes. Polymer 1B was prepared by precipitation in a What ser-ice mixture and filtration and then dried at 40 ° C under vacuum.

3. Preparation of polymer 1C

The Process for the preparation of polymer 1B was repeated, however the IR dye IR 66e was used instead of the IR Trump dye, which is 2- [2- [2-thiophenyl-3- [2- (1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene) ethylidene] -1-cyclohexene -l-yl] ethenyl] -1,3,3-trimethyl-3H-indoliunichlorid is.

Production Example 2

1. Preparation of Polymer 2A

To a solution of 20 g of Gantrez ^® AN 119 (copolymer of vinyl ether and maleic anhydride available from GAF Chemical Corporation USA; quantitative ratio of the comonomers of 1: 1) in 100 g of anhydrous N-methylpyrrolidinone were 24.02 g of glacial acetic acid was slowly added anhydrous with stirring; it was ensured that no resin precipitated. At room temperature, a mixture of 4.42 g of aniline and 8.81 g of 4-hydroxyaniline was added very slowly with stirring to this solution. The solution was stirred for 16 hours. After all the anhydride groups had reacted (confirmed by IR spectroscopy), the solution was heated at 100 ° C for 3 hours. The solution was then added to 2 L of water containing 5 mL of concentrated hydrochloric acid, whereupon the polymer precipitated. The precipitated polymer was filtered off and dried at 50 ° C.

2. Preparation of Polymer 2 B

To 7 g of polymer 2A dissolved in 56 g of methoxyethanol were added 0.102 g of NaOH dissolved in 21 g of ethanol and stirred overnight at room temperature. The reaction mixture was poured slowly into a mixture of 1400 g of H ₂ O and 0.476 g of p-toluenesulfonic acid. The resulting precipitate was filtered off, washed and dried at 50 ° C.

Comparative Example 1

An aluminum support for lithography electrochemically roughened, anodized and hydrophilized with polyvinylphosphonic acid was dissolved with a coating solution of 5 g of polymer 1A and 0.882 g of IR Trump dye dissolved in 45 g of a mixture of methyl ethyl ketone (65% by volume), Dowanol PM ( 15 vol.%), BLO (?) (10 vol.%) And H ₂ O (10 vol.%) Coated; after drying at 135 ° C for 45 seconds in an oven, the dry layer weight was found to be 1.38 g / m ² . The plate was dyed very green.

The developability of the coating was examined as follows:
It was Gold Star ^® developer in 5 s intervals dropped onto respectively different areas of the coating and after a total of 30 s rinsed with water; the longest exposure time was therefore 30 s and the shortest 0 s. It was found that after 5 s exposure time of the developer, the coating was completely removed when rinsing with water.

In addition, the panel was tested for resistance to blanket cleaning solution (95% UV wash by Varn Products, UK, and 5% H ₂ O). For this purpose, at 30 s intervals, cleaning solution was added dropwise to different locations of the plate and rubbed off after a total of 3 minutes with a cloth; the longest exposure time was therefore 3 minutes and the shortest 30 s. The removal of the coating was measured indirectly via the (normalized) color density. The decrease in color density with time is in 1 represented graphically; a significant decrease was noted, which means that the resistance to the wash solution is unsatisfactory.

example 1

An aluminum support for lithography electrochemically roughened, anodized and hydrophilized with polyvinylphosphonic acid was dissolved with a coating solution of 1.25 g of polymer 1B dissolved in 15 g of a mixture of methyl ethyl ketone (65% by volume), Dowanol PM (15% by volume). ), BLO (10 vol.%) And H ₂ O (10 vol.%) Coated; after drying at 135 ° C for 45 seconds in an oven, the dry layer weight was found to be 1.35 g / m ² . The plate was dyed very green.

The developability test described in Comparative Example 1 was carried out. When using Gold Star ^® developer s exposure, the coating was completely removed during rinsing after 5; the coating dissolved in the form of a skin. When using a 1: 1 mixture of Gold Star ^® (positive developer), and 956 ^® (negative developer) s exposure, the coating was completely removed during rinsing after 5; a skin was not noticed.

From the fact that when using Gold Star ^® coating in the form of a skin was removed, whereas this was not the case with Comparative Example 1, it can be concluded that the polymer 1A in the production of polymer 1B (Preparation Example 1 (2)) was changed.

The result of the test for resistance to blanket cleaning solution is in 1 shown graphically. There was no decrease in color density, so that there was a high resistance to the cleaning solution. Again, this is an indication that Polymer 1A was changed in Preparation Example 1 (2).

Comparative Example 2

example 1 was repeated, but instead of polymer 1B, polymer was used 1C used. The plate showed a gray color.

The developability test described in Comparative Example 1 was carried out. After 5 sec exposure time of the developer, rinsing with water completely removed the coating; Skin formation was not observed. The result of the test for resistance to blanket cleaning solution (see 1 ) shows that the durability was unsatisfactory.

Example 2 and Comparative Examples 3 and 4

Two-layered sheets were prepared by first coating the backing described in Comparative Example 1 as described in Comparative Example 1 (Comparative Example 3), Example 1 (Example 2) and Comparative Example 2 (Comparative Example 4), and then coating 0.8 g / m ² dry layer weight was applied. For the preparation of the topcoat, 8 g of 15 mol% of tosylated N13 novolac (available from Diversitec Corp., USA) was dissolved in 40 g of a mixture of 92% by volume of diethyl ketone and 8% by volume of Dowanol PMA.

The thus prepared two-layered plates were irradiated imagewise (full area and various pixel patterns) with a Creo Quantum 800 exposure unit (12 watts, 225 rpm, 140 mJ / cm ² ).

The plates of Comparative Example 3 and Comparative Example 4 were developed at 24 ° C in a Mercury Processor ^® Gold Star ^®, while for the sheet of Example 2 is a 1: 1 mixture of Gold Star ^® and 956 ^® was used. In Comparative Example 3 and Example 2, respectively, clear images and a clean background were obtained, while in Comparative Example 4 images of poor quality and unclean background were obtained.

TLC

It became a silica gel 60 F254 thin layer chromatography plate used by Merck.

• 1) Lösungsmittelgemisch: n-Butanol/H₂O/Ethanol/Eisessig (60:20:10:0,5 Volumenverhältnis); das Lösungsmittelgemisch wurde als Laufmittel bei der Dünnschichtchromatographie verwendet und zum Herstellen der aufzubringenden Probenlösung. Polymer 1A (85 Gew.%, bezogen auf Feststoffgehalt), IR Trump dye (15 Gew.%, bezogen auf Feststoffgehalt).
• 2) Lösungsmittelgemisch wie bei 1) Polymer 1B
• 3) Lösungsmittelgemisch wie bei 1) Polymer 1C

The following solutions were applied:

• 1) solvent mixture: n-butanol / H ₂ O / ethanol / glacial acetic acid (60: 20: 10: 0.5 by volume); the solvent mixture was used as the eluent in thin-layer chromatography and for preparing the sample solution to be applied. Polymer 1A (85% by weight, based on solids content), IR Trump dye (15% by weight, based on solids content).
• 2) solvent mixture as in 1) Polymer 1B
• 3) solvent mixture as in 1) Polymer 1C

While at solution 1) and 3) the color spot migrated with the mobile phase changed the position of the color spot in solution 2) not (that is, the Spot remained at the job site).

The The fact that the dye did not migrate in solution 2) leaves the To conclude that the dye was bound to the polymer and due its high molecular weight could not migrate; in solutions 1) and 3), on the other hand, no molecular weight increase had occurred, so that the dye migrated normally with the eluent.

Claims (16)

IR-absorber-modified polymer obtainable by reacting (a) a polymer having phenolic OH groups and / or -SO ₂ NHR groups in which R is independently selected from H, alkyl, aryl and aralkyl in the side chain, wherein the polymer is soluble in an aqueous alkaline solution and the solubility is not altered by IR radiation, with (b) a photothermal conversion material capable of absorbing radiation from a wavelength range of 750 to 1300 nm and converting it to heat, wherein the photothermal conversion material in the molecule has at least one covalently bonded halogen atom X which can react with a phenolic OH group or -SO ₂ NHR group under HX cleavage, under alkaline conditions, wherein the modified polymer is soluble in aqueous alkaline solution, and the solubility does not change due to IR radiation. An IR absorber-modified polymer according to claim 1, wherein polymer (a) is selected from: (i) a polyvinyl acetal containing the following units:

wherein m is an integer of 1 to 5, n is 0 or an integer of 1 to 4, m and n ≤ 5, and each R is independently selected from an alkyl group, an alkoxy group and a halogen atom; (ii) polyvinylphenols and their copolymers; and (iii) a polymer having a maleimide unit of the following structure (D)

wherein R, m and n are as defined above. IR-absorber-modified polymer according to claim 1 or 2, wherein the halogen atom X is a chlorine atom. The IR absorber-modified polymer according to any one of claims 1 to 3, wherein the photothermal conversion material (b) is a cyanine dye of the formula (I)

wherein each Z ^{1 is} independently S, O, NR ^a or C (alkyl) ₂ ; each R ¹ independently represents an alkyl group, an alkylsulfonate residue or an alkylammonium residue; R '' is a halogen atom, SR ^a , OR ^a , SO ₂ R ^a or NR ^a ₂ ; each R '''independently represents a hydrogen atom, an alkyl group, -COOR ^a , -OR ^a , -SR ^a , -NR ^a ₂ or a halogen atom; R '''may also be a benzo-fused ring; A ^{- stands} for an anion; --- represents an optionally present carbocyclic five- or six-membered ring; R ^{a represents} a hydrogen atom, an alkyl or aryl radical; each b may independently be 0, 1, 2 or 3, with the proviso that at least one of R '' and R '''is a halogen atom. IR-modified polymer according to a the claims 1 to 4, wherein the reaction of (a) with (b) at elevated temperature takes place. IR-modified polymer according to a the claims 1 to 5, wherein in the reaction 0.2 to 30 wt.% Photothermal Conversion material (b), based on the total amount of Component (a) and (b) are used. A process for producing an IR absorber-modified polymer comprising reacting (a) a polymer having phenolic OH groups and / or -SO ₂ NHR groups in which R is independently selected from H, alkyl, aryl and aralkyl the side chain, wherein the polymer is soluble in aqueous alkaline solution and the solubility is not changed by IR radiation, with (b) a photothermal conversion material capable of absorbing radiation from a wavelength range of 750 to 1300 nm and into heat, wherein the photothermal conversion material in the molecule has at least one covalently bonded halogen atom X, which can react with a phenolic OH group or -SO ₂ NHR group with HX cleavage, under alkaline conditions. Method according to claim 7, wherein the reaction under elevated Temperature takes place. Radiation-sensitive negative-working element, full (a) a carrier with hydrophilic surface and (b) a layer on the hydrophilic surface of the support this layer being a modified one as defined in claims 1 to 6 Contains polymer, in aqueous-alkaline Developer soluble is insoluble by IR radiation but in aqueous alkaline developer. Radiation-sensitive element according to claim 9, wherein the layer also (i) at least one compound which forms an acid by the action of heat, and (ii) at least one by acid contains crosslinkable component. Radiation sensitive positive working element, full (a) a carrier with hydrophilic surface, (B) a first layer on the hydrophilic surface of the support and (c) a cover layer, in which the first layer is a modified polymer as defined in claims 1 to 6 contains in aqueous-alkaline Developer soluble is and the solubility not changed by IR radiation and wherein the topcoat is in aqueous alkaline developer not soluble or permeable to it, but by IR radiation in aqueous-alkaline Developer soluble or becomes penetrable by it. Radiation-sensitive element according to claim 11, wherein the cover layer in a strongly alkaline-aqueous Developer insoluble Contains polymer, that by IR radiation soluble in the developer or becomes permeable to it. Radiation-sensitive element according to claim 11, wherein the cover layer in a strongly alkaline-aqueous Developer soluble Polymer and a solubility inhibitor contains wherein the interaction between polymer and solubility inhibitor by IR radiation so changed is that the irradiated areas in the developer or soluble be penetrated by him. Radiation-sensitive element according to claim 11, wherein the cover layer in an aqueous alkaline developer with pH <11 insoluble, at pH> 11 but soluble Contains polymer, that is soluble in a developer of pH <11 by IR radiation or becomes permeable by him. Method for producing an imaged element, full: (a) providing one as in any one of claims 9 to 14 defined radiation-sensitive element; (b) imagewise Irradiate the element with IR radiation or imagewise exposure the element of a heat source; (C) Developing the imagewise irradiated element with an aqueous-alkaline Developer. The method of claim 15, wherein in step (b) imagewise with a computer-controlled IR-La is irradiated.