Lithographic printing plate precursors, methods of use and manufacture

Abstract

On-press developable negative-working infrared radiation-sensitive lithographic plate precursors have an aluminum-containing substrate with at least an inner layer of aluminum oxide and an outer layer of aluminum oxide. A hydrophilic layer is present on the outer layer of aluminum oxide and contains a phosphorus-containing compound represented by formula (I) at a coverage of 50-300 mg / m 2 These precursors have on-press developable negative-working infrared radiation-sensitive imageable layers with at least a free-radically polymerizable component; an initiator composition that provides free radicals upon exposure to imaging infrared radiation; an infrared radiation absorber having an anionic chromophore; and optionally a polymeric binder that is different from all other components. Such precursors can be imaged and on-press developed to provide lithographic printing plates and can be readily prepared using a particular sequence of steps including multiple anodization steps.

Description

Technical Field

[0001] This invention relates to a machine-developable negative lithographic printing plate precursor (“precursor”) that comprises an inventive aluminum-containing substrate prepared using at least two separate anodizing processes to provide at least an alumina inner layer and an alumina outer layer. The aluminum-containing substrate also has a unique hydrophilic layer disposed on the alumina outer layer, the hydrophilic layer comprising a predominantly phosphorus-containing compound dry coating at a specific dry coverage ratio. The invention also relates to a method for infrared imaging and washing such a precursor to provide a lithographic printing plate. It further relates to a method for preparing such an inventive precursor from the inventive aluminum-containing substrate. Background Technology

[0002] In offset printing, an ink-receiving area, called the image area, is formed on the hydrophilic surface of the substrate. When the printing plate surface is wetted with water and offset printing ink is applied, the hydrophilic area retains water and repels the offset printing ink, while the ink-receiving image area accepts the offset printing ink and repels water. Alternatively, in the case of using a blanket roller, the offset printing ink is transferred from the offset printing plate to the surface of the material on which the image is to be reproduced.

[0003] The imageable element or lithographic plate precursor used to prepare a lithographic printing plate typically comprises one or more radiation-sensitive imageable layers disposed on the outermost hydrophilic surface of a substrate. After imaging, the exposed (imaged) or unexposed (unimaged) areas of one or more radiation-sensitive layers can be removed using a suitable developer, exposing the outermost hydrophilic surface of the substrate. If the exposed areas are removable, the lithographic plate precursor is considered a positive plate. Conversely, if the unexposed areas are removable, the lithographic plate precursor is considered a negative plate.

[0004] The radiation-sensitive photopolymerizable composition used in negative lithographic printing plate precursors typically comprises a free radical polymerizable component, one or more radiation absorbers, an initiator composition, and optionally one or more polymer binders different from the other indicated components.

[0005] In recent decades, industry has emphasized simplifying lithographic plate preparation methods, including omitting the preheating step (development heating) and using lithographic inks and / or dampening solutions for in-machine development (DOP) to remove unwanted (unexposed) imageable layer material from the lithographic plate precursor. Such negative lithographic plate precursors should be designed by balancing numerous features within the element structure to achieve optimal plate durability, in-machine development capability, imaging speed, storage stability, scratch resistance, and other industry-required properties. Achieving simultaneous optimization of all these properties is not an easy task, as a chemical composition or structural feature that provides an optimal level of one or two properties may result in the loss of another.

[0006] The unique anodized substrate described in U.S. Patent Application Publication 2018 / 0250925 (Merka et al.) provides an advancement in the art for machine-developable lithographic printing plate precursors.

[0007] It remains necessary to mitigate the adverse effects of atmospheric ozone on imaging chemistry in precursors. Ozone can reduce the imaging sensitivity of certain infrared radiation absorbers (i.e., those containing cationic chromophores with a net positive charge). Precursors containing such compounds can exhibit reduced print durability. To effectively address this issue, researchers have learned that using infrared radiation absorbers containing anionic chromophores with a net negative charge or acidic groups in the imaging chemistry of imageable layers is useful.

[0008] However, the use of such "anionic" infrared radiation absorbers raises another problem when applying an imaging layer to an aluminum-containing substrate with multiple alumina layers, prepared using sulfuric acid in the final anodizing process as described in U.S. Patent Application Publication 2018 / 0250925 (Merka et al.). Such anodizing processes can generate aluminum sulfate, which is water-soluble and can migrate into the imaging layer, forming aluminum salts with the anionic infrared radiation absorbers. This effect severely impairs the imaging sensitivity of those infrared radiation absorbers.

[0009] Therefore, it is necessary to solve these multiple problems without sacrificing imaging sensitivity and print durability. Summary of the Invention

[0010] This invention provides a lithographic printing plate precursor, comprising: Aluminum-containing substrates with hydrophilic surfaces, and An infrared radiation-sensitive imaging layer for negative lithography, which is machine-developable and can be placed on the hydrophilic surface of an aluminum-containing substrate. The aluminum-containing substrate includes: An aluminum plate with a ground and etched surface; An alumina inner layer is disposed on the ground and etched surface, the alumina inner layer having an average dry thickness (T) of at least 300 nm and at most including 3000 nm. i ), and contains many average internal micropore diameters (D i Micropores less than or equal to 11 nm, wherein the inner layer of alumina contains aluminum sulfate; An outer layer of alumina is disposed above the inner layer of alumina, and the outer layer of alumina contains a number of average external micropores with a diameter (D). o The external micropores are at least 12 nm and at most 50 nm in size, and have an average dry thickness (T) of at least 20 nm and at most 650 nm. o );and A hydrophilic layer disposed on the outer layer of alumina, wherein the hydrophilic layer comprises: (1) one or more phosphorus-containing compounds having a C1 dry coverage and represented by the following formula (I): Formula (I) Where n is 0 or an integer from 1 to 10, and -OM represents -OH or -O. - M + And M + It is a monovalent cation; and optionally (2) one or more hydrophilic polymers having a C2 dry coverage in the presence, (1) The C1 dry coverage of one or more phosphorus-containing compounds is at least 50 mg / m³. 2 And at most including 300 mg / m 2 And when (2) one or more hydrophilic polymers are present, the ratio of C1 dry coverage to C2 dry coverage is at least 11:9; and The machine-developable negative lithography infrared radiation-sensitive imageable layer comprises the following components (a) to (c) and optional component (d): (a) One or more components that are free radical polymerizable; (b) An initiator composition that provides free radicals when a machine-developable infrared-sensitive imageable layer of a negative plate is exposed to imaging infrared radiation; (c) One or more infrared radiation absorbers comprising anionic chromophores having a net negative charge or an acidic group; and optionally... (d) One or more polymeric adhesives that are all different from all components (a), (b) and (c).

[0011] The present invention also provides a method for providing a lithographic printing plate, comprising: The lithographic printing plate precursor of any precursor embodiment of the present invention is exposed imagewise to imaging infrared radiation to form an imageable layer having exposed and unexposed areas exposed to image infrared radiation, and Using lithographic printing ink, dampening solution, or both, unexposed areas are removed from the imageable layer exposed by infrared radiation to form a lithographic printing plate.

[0012] Furthermore, the present invention provides a method for preparing a lithographic printing plate precursor, which comprises, in sequence: A) Provide aluminum plates with surfaces that have been electrochemically or mechanically ground and etched; B) A first anodizing treatment is applied to the aluminum-containing plate to form an aluminum oxide outer layer on the surface that has been electrochemically or mechanically ground and etched. The aluminum oxide outer layer contains a number of average external micropores with a diameter (D). o The external micropores are at least 12 nm and at most 50 nm in size, and have an average dry thickness (T) of at least 20 nm and at most 650 nm. o ); C) Rinse the outer layer of alumina; D) Applying additional anodizing treatment to the aluminum-containing plate using sulfuric acid to form an inner aluminum oxide layer beneath the outer aluminum oxide layer, the inner aluminum oxide layer having an average dry thickness (T) of at least 300 nm and at most including 3000 nm. i ), and contains many average internal micropore diameters (D i Micropores less than or equal to 11 nm, wherein the inner layer of alumina contains aluminum sulfate; E) Rinse the outer and inner layers of alumina; F) A hydrophilic layer is provided above the alumina outer layer, wherein the hydrophilic layer comprises: (1) one or more phosphorus-containing compounds having a C1 dry coverage and represented by the following formula (I): Formula (I) Where n is 0 or an integer from 1 to 10, and -OM represents -OH or -O. - M + And M + It is a monovalent cation; and optionally (2) one or more hydrophilic polymers having a C2 dry coverage in the presence, (1) The C1 dry coverage of one or more phosphorus-containing compounds is at least 50 mg / m³. 2 And at most including 300 mg / m 2 And when (2) one or more hydrophilic polymers are present, the ratio of C1 dry coverage to C2 dry coverage is at least 11:9; and G) Form an infrared-sensitive imageable layer on top of the alumina outer layer for machine development of negative plates. The machine-developable negative lithography infrared radiation-sensitive imageable layer comprises the following components (a) to (c) and optional component (d): (a) One or more components that are free radical polymerizable; (b) An initiator composition that provides free radicals when a machine-developable infrared-sensitive imageable layer of a negative plate is exposed to imaging infrared radiation; (c) One or more infrared radiation absorbers comprising anionic chromophores having a net negative charge or an acidic group; and optionally... (d) One or more polymeric adhesives that are all different from all components (a), (b) and (c).

[0013] In some embodiments of the manufacturing method of the present invention, the method further includes, between step B) and C): C') A second anodizing treatment is applied to the aluminum-containing plate to form an aluminum oxide intermediate layer under the aluminum oxide outer layer, the aluminum oxide intermediate layer having an average dry thickness (T) of at least 60 nm and at most including 300 nm. m ), and contains many average intermediate micropore diameters (D m ) is at least 20 nm and at most includes 60 nm of intermediate micropores, wherein D m Greater than D o D o Greater than D i And the average dry thickness of the outer layer of alumina (T) o (less than 150 nm, and) The additional anodizing process in step D) is a third anodizing process used to form an inner layer of aluminum oxide under the intermediate layer of aluminum oxide.

[0014] The practice of this invention has significantly reduced the problem of decreased imaging sensitivity when anionic infrared radiation absorbers are present in imaging chemistry. Specifically, it has been found that imaging sensitivity is maintained when anionic infrared radiation absorbers are used in imaging chemistry, especially when phosphoric acid, phosphoric acid condensates, or phosphates constitute the dominant component of the hydrophilic layer between the aluminum-containing substrate and the machine-developable infrared-sensitive imageable layer of the negative plate. These advantages are particularly evident when the aluminum-containing substrate has two or more layers of alumina produced by anodizing (the final anodizing process is performed using sulfuric acid). The anodized alumina produced using sulfuric acid contains aluminum sulfate. Although aluminum sulfate is readily soluble in water in its pure form, the aluminum sulfate trapped within the anodized alumina structure cannot be easily removed by a water rinsing step within the practical timeframe of a typical printing plate precursor manufacturing machine. During the natural storage of lithographic printing plate precursors derived from such aluminum-containing substrates (especially in humid environments), the aluminum sulfate retained in the aluminum-containing substrate can be slowly released.

[0015] It has been found that the release of aluminum sulfate into the channels of an infrared radiation-sensitive imageable layer in a machine-developable negative lithography plate can be achieved at a concentration of at least 50 mg / m². 2 And at most including 300 mg / m 2The presence of C1 dry coverage (1) effectively blocks one or more phosphorus-containing compounds. Therefore, it can effectively prevent the formation of salts between the anionic chromophores of (c) one or more infrared radiation absorbers and the aluminum ions released from the aluminum-containing substrate. If such salt formation is not prevented, the effectiveness of (c) one or more infrared radiation absorbers is significantly reduced. Detailed Implementation

[0016] definition This document uses the term "aluminum-containing plate" to refer to aluminum-containing materials or materials containing other metals (sheets, meshes, strips, flakes, or other forms) that may be subsequently processed to prepare a "substrate" as described in more detail below. Sometimes, this term is referred to in the art as a "support".

[0017] Average external micropore diameter (D) o The diameter (in nanometers (nm)) can be determined by a top-view SEM image taken from the substrate surface at a magnification of at least 50,000X before the application of the hydrophilic layer and the infrared radiation-sensitive imageable layer. The external micropore diameter (D) of the lithographic printing plate precursor can also be determined by... o The organic layer was stripped away with a suitable solvent, and the outer portion of the alumina layer, approximately 20 nm–80 nm thick, was optionally removed using a suitable technique such as argon ion beam sputtering. A top-view SEM image was then captured. The average value was determined by examining more than 200 external micropores.

[0018] Average internal micropore diameter (D) i The cross-sectional area can be determined by a cross-sectional SEM image with a magnification of at least 50,000X. The cross-section can be generated by bending the lithographic printing plate precursor or its substrate after the imageable and hydrophilic layers have been removed. During bending, cracks form in the alumina layer, and new surfaces are typically formed at the weakest points (which are usually located at the thinnest walls between adjacent internal micropores). Thus, the new cracked surfaces provide a cross-sectional view of numerous micropores. For the purposes of this invention, it is not necessary to determine the precise average internal micropore diameter (D). i (This is acceptable, provided that at least 90% of the exposed micropore cross-sections have a width of less than 11 nm.)

[0019] Average dry thickness (T) of the outer layer of alumina in nanometers (nm). o ), the average dry thickness of the alumina intermediate layer and the average dry thickness of the alumina inner layer (T) i Each can be determined by a cross-sectional SEM image with a magnification of at least 50,000X. The cross-section of the alumina layer can be exposed by a crack formed by bending the lithographic printing plate precursor or its aluminum-containing substrate. The cross-section of each alumina layer can also be exposed by cutting a slit through the alumina layer using a technique well known in the art—focused ion beam (FIB).

[0020] In some implementations, the micropore density of the outer layer of alumina (C o (per micropore / µm) 2 The number of micropores can be determined from a top-view SEM image with a magnification of at least 50,000X by counting the number of micropores in a square predetermined region having an area of, for example, 500 nm × 500 nm.

[0021] Additionally, in some implementations, the porosity (P) of the outer layer of alumina is... o It can be constrained by each of the following equations: 0.3 < P o < 0.8 or 0.3 < P o < 0.6, Where P o Defined as 3.14(C) o (D) o 2 ) / 4,000,000.

[0022] As used herein, the term “infrared radiation absorber” refers to a compound or material that absorbs electromagnetic radiation in a defined region, and generally refers to a compound or material, or a mixture thereof, that has maximum absorption in a region of at least 750 nm and at most 1400 nm.

[0023] For clarification of the definitions of any terms related to polymers, please refer to, for example, "Glossary of Basic Terms in Polymer Science" published by the International Union of Pure and Applied Chemistry (IUPAC). Pure Appl. Chem. 68, 2287-2311 (1996). However, any definitions explicitly set forth herein should be considered definitive.

[0024] Unless otherwise specified, the term "weight%" refers to the amount of component or material based on the total solids of the composition, formulation, or dried layer. Unless otherwise specified, the percentage of total solids for the dried layer or the formulation or composition used to form the dried layer may be the same.

[0025] use The lithographic printing plate precursors of the present invention (“precursors”) are used to form lithographic printing plates for lithographic printing, for example, using lithographic printing inks, dampening solutions, or both lithographic printing inks and dampening solutions. These precursors are prepared to have the structure and composition described below. Furthermore, the lithographic printing plate precursors of the present invention are designed as negative plates and machine-developable using suitable materials and manufacturing processes described below to provide machine-developable negative plate infrared radiation-sensitive formulations and imageable layers.

[0026] However, if the user requires it, it may still be possible to use a suitable developer to develop such invention precursors offline.

[0027] Invention substrate Generally, the aluminum-containing substrate of the lithographic printing plate can be obtained from aluminum or other metallic materials, such as aluminum alloys containing up to 10% by weight of one or more elements, including but not limited to manganese, silicon, iron, titanium, copper, magnesium, chromium, zinc, bismuth, nickel, and zirconium. The aluminum-containing support or aluminum alloy-containing support (or the “plate” or “raw material”) can have any form (including sheets, continuous meshes, and coiled strips) that can be further processed therefrom, provided that it has at least one (substantially flat) surface, which can be treated as described below to form a hydrophilic surface in the inventive substrate. Polymer films or papers containing pure aluminum layers or aluminum alloy layers deposited or laminated thereon may also be used.

[0028] The resulting aluminum-containing substrate should be thick enough to mechanically withstand the conditions of modern printing presses, but thin enough to be mounted (or wound) onto the printing cylinders of such machines. Therefore, the aluminum-containing substrate should also possess the appropriate tensile strength, elasticity, crystallinity, and electrical conductivity required for lithographic printing. These properties can be achieved by standard methods such as heat treatment or cold and hot rolling (typically used for manufacturing continuous lithographic printing support strips, screens, or rolls). The dry thickness of the resulting inventive substrate is typically at least 100 µm and at most, including, 600 µm.

[0029] Typical lithographic printing plate precursor manufacturing methods, including pre-etching, water rinsing, roughening, water rinsing, post-etching, and final water rinsing procedures, can be used to process the described aluminum-containing plate in combination with two or more anodizing processes described in more detail below.

[0030] A pre-etching step is typically performed on the aluminum substrate (or support) to remove oil, grease, metal, and other contaminants from or near the substrate surface. As is known in the art, this pre-etching step can be performed using sodium hydroxide or other alkaline aqueous solutions, or even certain organic solvents, at known concentrations, times, and temperatures. Alternative or additional degreasing steps may be performed using aqueous surfactant solutions, if necessary. Those skilled in the art will be able to conduct routine experiments to determine the optimal pre-etching conditions (e.g., optimal solution concentration, residence time, and temperature).

[0031] Typically, after a pre-etching step, the etched support is "roughened" in a suitable manner, for example, by using known electrochemical or mechanical roughening (or polishing) methods. In electrochemical polishing, the etched support may be treated with an alternating current in a 5-20 g / L hydrochloric acid solution. Nitric acid solutions (e.g., up to 2.5 wt%) or sulfuric acid solutions or mixtures may also be used for this purpose. Such electrochemical polishing solutions may also contain additives, such as corrosion inhibitors and stabilizers, including but not limited to metal nitrates, metal chlorides, monoamines, diamines, aldehydes, phosphoric acid, chromic acid, boric acid, lactic acid, acetic acid, and oxalic acid. For example, electrochemical polishing can be performed using the method described in U.S. Patent Application Publication 2008 / 0003411 (Hunter et al.). Those skilled in the art will be able to determine the optimal conditions for electrochemical or mechanical polishing through routine experimentation, as such methods are well known in the art. Mechanical polishing methods can be performed, for example, using a suitable brush, either alone or in combination with a slurry of abrasives such as silica particles or alumina particles. Alternatively, a combination of mechanical and electrochemical grinding methods can be used.

[0032] During roughening or grinding, contaminants may form on the surface of the aluminum-containing support, and these contaminants can be removed, for example, by using strong acidic or alkaline solutions in subsequent etching steps. 2 The surface of the support is treated to remove the contaminant. For example, post-etching can be performed using sodium hydroxide solution, trisodium phosphate solution, or sulfuric acid solution. The amount of post-etching can be controlled by setting the residence time, concentration, and temperature of the etching solution. The appropriate amount of post-etching also depends on the amount of roughening and the amount of contaminant formed in this step. The post-etching treatment should be sufficient to remove the contaminant, but it should not excessively damage the surface structure formed in the roughening step. Therefore, there are many combinations of parameters that can be considered by those skilled in the art during routine experiments to find the optimal post-etching conditions.

[0033] The aforementioned steps produce an electrochemically ground (roughened) or mechanically ground (roughened) and etched surface in an aluminum-containing plate (or support) provided in step A) of the manufacturing method according to the invention.

[0034] The subsequent steps according to the invention include at least a first anodizing treatment and a second anodizing treatment (both of which are essential to the invention) to form an outer alumina layer and an inner alumina layer, respectively. The method of the invention does not require additional anodizing treatments (i.e., a third or more anodizing treatments), but one or more additional anodizing treatments are possible and therefore optional.

[0035] Typically, a sulfuric acid or phosphoric acid (electrolyte) solution can be used to perform a first anodizing treatment and a second anodizing treatment for at least 1 second and at most 250 seconds at a suitable time at a temperature of at least 20°C and up to 70°C, sufficient to provide up to 4 g / m 2 The total dry alumina coverage (the sum of the outer and inner alumina layers). The conditions for the first and second anodizing treatments are described below.

[0036] Therefore, in step B), a suitable aluminum-containing plate having a surface that has been electrochemically or mechanically ground and etched as described above is subjected to a first anodizing treatment to form an alumina outer layer on the electrochemically or mechanically ground and etched surface. For example, the first anodizing treatment can be performed using an electrolyte composition containing at least 50 g / L and at most 350 g / L of phosphoric acid or at least 150 g / L and at most 300 g / L of sulfuric acid, and a suitable amount of aluminum ions (e.g., 5 g / L). These solution amounts can be optimized with respect to the type of acid, acid concentration, aluminum ion concentration, residence time, and temperature to achieve the desired alumina outer layer properties as described herein. Representative details of such a first anodizing treatment are illustrated in the working embodiments described below or in known techniques, such as U.S. Patent Application Publication 2018 / 0250925 (Merka et al.), U.S. Patent Nos. 9,259,954 (Tagawa et al.), 8,978,555 (Kurokawa et al.), 8,789,464 (Tagawa et al.), and 8,783,179 (Kurokawa et al.). Particularly useful is the use of phosphoric acid for the first anodizing treatment.

[0037] The resulting alumina outer layer contains many average external micropores with a diameter (D) o The external micropores are at least 12 nm or at least 15 nm, and at most 30 nm or even at most 50 nm. Additionally, the average dry thickness (T) of the alumina outer layer... o The pore size can be at least 20 nm, at least 50 nm, at least 130 nm, or even at least 150 nm, and at most and including 300 nm, at most and including 400 nm, or at most and including 650 nm. In some embodiments, the micropore density (C0) of the anodized outer layer is... o Typically, it can be at least 500 micropores / µm 2 And includes up to 3,000 micropores / µm 2 .

[0038] Furthermore, in some implementations, the average external micropore diameter (D, in nanometers) of the alumina outer layer can be further constrained or correlated according to each of the following equations. o) and per micropore / µm 2 The micropore density (C) of the calculation o ): 0.3 < P o < 0.8 or 0.3 < P o < 0.6, Porosity P o As defined above.

[0039] Once the required time for the first anodizing process has been completed, the formed outer layer of alumina can be rinsed with a suitable solution (e.g., water) at a suitable temperature and time in step C) as needed to remove residual acid and aluminum, and the first anodizing process can be stopped.

[0040] In some of these, the average external micropore diameter (D) from the first anodizing treatment o In embodiments where the value is less than that specified above (typically the first anodizing treatment is performed in sulfuric acid), a pore-expansion treatment may be added after the first anodizing treatment and an optional rinsing treatment. The pore-expansion treatment may be performed in an acidic or alkaline solution. Details regarding the pore-expansion treatment can be found in the known art, such as U.S. Patents 9,259,954, 8,978,555, 8,789,464, and 8,783,179 (all identified above). Following such a pore-expansion treatment, another rinsing step may be performed using a suitable solution such as water to remove the acidic or alkaline components used in the pore-expansion treatment.

[0041] Step D) is then performed using a suitable electrolyte composition to form an inner alumina layer beneath the outer alumina layer. This electrolyte composition may contain at least 100 g / L and at most 350 g / L of sulfuric acid, and a suitable amount (e.g., 5 g / L) of aluminum ions. These solution amounts can be optimized with respect to acid concentration, aluminum ion concentration, residence time, and temperature to achieve the desired alumina inner layer properties as described herein. Details of this second anodizing process are illustrated in the working examples described below. This additional anodizing process is typically a “second” and final anodizing process, but in some embodiments, it is a third and final anodizing process used to form an inner alumina layer beneath the intermediate alumina layer (described below).

[0042] The resulting alumina inner layer, disposed on the ground and etched surface of the substrate, contains a number of average internal micropores with a diameter (D). i Internal micropores less than or equal to 11 nm. In such embodiments, D o With Di The ratio can be greater than 1.1:1, or even greater than 1.5:1. Additionally, the average dry thickness (T) of the alumina inner layer... i It can be at least 300 nm or at least 500 nm, and at most 1500 nm or at most 3000 nm.

[0043] In some implementations, the alumina outer layer is directly disposed on the alumina inner layer, and the average dry thickness (T) of the alumina outer layer is... o The internal micropore diameter is at least 50 nm, and the average internal micropore diameter (D) is... i The average dry thickness (T) of the alumina inner layer is equal to or less than 11 nm. i The diameter of the inner hole is at least 500 nm, and the inner hole diameter (D) is at least 500 nm. i ) smaller than the average external micropore diameter (D o ).

[0044] Once the required time for the second anodizing process has been completed, the formed outer and inner alumina layers can be rinsed with a suitable solution (e.g., water) at a suitable temperature and time in step E) as needed to remove residual acid and aluminum salts, and the second anodizing process can be stopped.

[0045] In some embodiments of the invention, an aluminum-containing support is subjected to a second (but not final) anodizing treatment (step C') between steps C) and D) using a suitable acid or a mixture thereof for a suitable time and at a suitable temperature to provide an alumina intermediate layer beneath the alumina outer layer. This second anodizing treatment is performed after the first anodizing treatment and before the third anodizing treatment used to form the alumina inner layer. Therefore, an alumina intermediate layer is typically formed between the alumina outer layer and the subsequently formed alumina inner layer. In such embodiments, the formed alumina intermediate layer may have an average dry thickness (T0) of at least 60 nm and at most including 300 nm. m ), and may contain many average intermediate micropore diameters (D m The intermediate micropores are at least 20 nm and at most include 60 nm.

[0046] In such implementations, D m Greater than D o D o Greater than D i And T o It can be less than 150 nm, and the average dry thickness (T) of the alumina outer layer o (less than 150 nm)

[0047] After the alumina intermediate layer is formed, and before the alumina inner layer is formed as indicated above, the alumina outer layer and the alumina intermediate layer can be rinsed in step C) in the manner described above for the individual alumina outer layer.

[0048] According to the invention, a hydrophilic layer must be provided in step F) for application on the outer layer of alumina. The hydrophilic layer may be provided by a hydrophilic layer formulation comprising: (1) one or more phosphorus-containing compounds having a C1 dry coverage, the one or more phosphorus compounds being represented by formula (I) described below; and optionally (2) one or more hydrophilic polymers having a C2 dry coverage.

[0049] The hydrophilic layer has a total strength of at least 50 mg / m³. 2 And at most including 500 mg / m 2 The dry coverage. Typically, the hydrophilic layer is placed directly on the outer layer of alumina, so there is no intermediate layer. Since the outer layer of alumina contains micropores, some (parts) of the hydrophilic layer can be located inside these external micropores and in the micropores beneath the outer layer of alumina.

[0050] When both (1) and (2) are present, the ratio of C1 dry coverage to C2 dry coverage is at least 11:9, and this ratio may be at most and include 10:1 or at most and include 30:1, and is typically applied or set on the outer layer of alumina to provide dry coverage of the hydrophilic layer. The C1 dry coverage may be at least 50 mg / m³. 2 Or at least 75 mg / m 2 And at most including 200mg / m² 2 or up to and including 300 mg / m 2 C2 dry coverage can be zero or at most and includes 200 mg / m². 2 or at most including 100 mg / m 2 or up to and including 50 mg / m 2 .

[0051] The necessary (1) phosphorus-containing compounds for the hydrophilic layer are represented by the following formula (I): Formula (I) Where n is 0 or an integer from 1 to 10 (and n is especially 0). Additionally, -OM represents -OH or -O. - M + M + It is a monovalent cation, such as H+. +Sodium cations, potassium cations, ammonium cations, alkylammonium cations, dialkylammonium cations, trialkylammonium cations, or tetraalkylammonium cations. Examples of alkyl groups in alkylammonium cations, dialkylammonium cations, trialkylammonium cations, and tetraalkylammonium cations include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and sec-butyl. + Cations can be the same or different within the same molecule. Alkyl groups can be the same or different within the same cation. As a skilled chemist will readily determine, such alkyl groups can be substituted or unsubstituted. In various M... + Among cations, ammonium (NH4) + ) is especially suitable.

[0052] Additionally, for one or more phosphorus-containing compounds of formula (I) (1), a -OM group is selected such that it (alone or in a mixture of such compounds) exhibits a pH of at least 1 and at most 10, or at least 1 and at most 8, when dissolved in an aqueous solution containing 5% by weight of one or more phosphorus-containing compounds of formula (I) (1). When two or more phosphorus-containing compounds are used, a mixture of the two or more phosphorus-containing compounds is selected to similarly satisfy the pH requirement.

[0053] The compounds represented by formula (I) can be obtained from a variety of commercial sources or synthesized by skilled chemists using known raw materials and synthetic procedures.

[0054] The hydrophilic layer used in this invention practice optionally, but preferably, comprises (2) one or more hydrophilic polymers as defined above for the C2 dry coverage ratio. For the purposes of "hydrophilic" in relation to these polymers, it means that these polymers have a solubility of at least 1% in water at 25°C.

[0055] More specifically, (2) at least one of one or more hydrophilic polymers comprises a carboxylic acid side group, a phosphonic acid side group, or a phosphate side group, a salt of these groups (carboxylates, phosphonates, and phosphates), or a combination of two or more of these acidic side groups (or their salts). These acid and salt groups contribute to the water solubility of the hydrophilic polymer and thus to its adhesion to anodized aluminum surfaces. Therefore, these acid and salt groups can be considered as surface-bound hydrophilic groups. In addition to surface-bound hydrophilic groups, the hydrophilic polymer may also contain non-surface-bound hydrophilic groups that primarily contribute to its water solubility. Useful non-surface-bound hydrophilic groups include, but are not limited to, amide groups, hydroxyl groups, sulfonate groups, and polyoxyethylene groups.

[0056] (2) One or more hydrophilic polymers can be synthesized via condensation or addition polymerization using monomers having surface-bound hydrophilic groups and non-surface-bound hydrophilic groups. Addition polymerization of suitable olefinically unsaturated polymerizable monomers can be initiated using radical initiators, cationic initiators, and anionic initiators. Surface-bound and non-surface-bound hydrophilic groups on these hydrophilic polymers can be introduced via polymerization of monomers having these groups or formed by the reaction of a suitable precursor polymer having precursor side groups capable of being converted into surface-bound and non-surface-bound hydrophilic groups. Among the various synthetic techniques for preparing one or more hydrophilic polymers of the present invention, radical addition polymerization of monomer compositions comprising an olefinically unsaturated polymerizable monomer having surface-bound (hydrophilic) groups and optionally an olefinically unsaturated polymerizable monomer having non-surface-bound hydrophilic groups is particularly useful.

[0057] Examples of useful olefinically unsaturated polymerizable monomers having surface-bound hydrophilic groups include, but are not limited to, acrylic acid, methacrylic acid, itaconic acid, maleic acid, vinylphosphonic acid, acryloyloxyethyl phosphate, methacryloyloxyethyl phosphate, polyethylene glycol acrylate phosphate, and polyethylene glycol methacrylate phosphate.

[0058] Examples of useful olefinically unsaturated polymerizable monomers with non-surface-bound hydrophilic groups include, but are not limited to, methacrylamide, acrylamide, etc. N,N -Dimethylacrylamide, N -Hydroxyethylmethylacrylamide, N -(methoxymethyl)acrylamide, hydroxyethyl acrylate, hydroxyethyl methacrylate, N-vinylpyrrolidone, sodium p-styrene sulfonate, sodium acrylamide propyl sulfonate, and polyethylene glycol methyl ether methacrylate. Mixtures of two or more of these monomers can be used to provide a wide variety of repeating units. Among monomers having non-surface-bound hydrophilic groups, those having at least one amide group such as acrylamide or methacrylamide are particularly useful. In some embodiments, repeating units derived from monomers having amide groups may account for up to 95 mol% of the total repeating units in the hydrophilic polymer, and repeating units derived from monomers having hydrophilic surface-bound groups (e.g., one or more of carboxylic acid groups, carboxylates, or carboxyl esters) may account for up to and include 50 mol% of the total repeating units in the hydrophilic polymer, typically up to and including 40 mol% or up to and including 30 mol%.

[0059] Therefore, in some embodiments in which one or more hydrophilic polymers are present in the hydrophilic layer, (2) one or more hydrophilic polymers include hydrophilic polymers comprising repeating units of: repeating units comprising a salt or ester of a carboxylic acid, phosphonic acid, phosphate group, or any of these acids; and optionally repeating units comprising an amide group.

[0060] If (2) there is a mixture of one or more hydrophilic polymers, they may have different repeating unit compositions and / or different repeating unit amounts.

[0061] In addition to (1) one or more phosphorus-containing compounds (with or without (2) one or more hydrophilic polymers), the hydrophilic layer may also contain one or more surfactants, leveling agents, chelating agents and biocides.

[0062] The method for forming the hydrophilic layer can be carried out in any suitable manner as described, for example, in U.S. Patent Application Publication 2014 / 0047993 (as stated above)

[0058] -

[0061] . A particularly useful technique for forming the hydrophilic layer is to directly coat the outer layer of alumina with a desired amount of the hydrophilic layer formulation in a suitable solvent such as water, and then allow the resulting wet coating to dry.

[0063] After all these necessary processes, the resulting aluminum-containing substrate of the invention, in any suitable form (e.g., flat sheet or continuous mesh or roll), is ready for use in preparing a lithographic printing plate precursor according to the invention.

[0064] Infrared radiation-sensitive imageable layer and precursor Generally, suitable machine-developable negative lithography infrared-sensitive imageable layer formulations, as described in more detail below, can be used to form or place a single machine-developable negative lithography infrared-sensitive imageable layer over a hydrophilic layer on an aluminum-containing substrate of the invention in a suitable manner.

[0065] Negative plate making, lithographic printing plate precursor: The precursor of the present invention can be formed by suitably applying a machine-developable negative lithography infrared-sensitive composition as described below to a suitable inventive aluminum-containing substrate (as described above) to form a machine-developable negative lithography infrared-sensitive imageable layer on the substrate. Generally, the machine-developable negative lithography infrared-sensitive composition (and the resulting machine-developable negative lithography infrared-sensitive imageable layer) comprises, as essential components, (a) one or more radically polymerizable components; (b) an initiator composition that provides radicals upon exposure to imaging radiation (e.g., infrared radiation as defined herein); and (c) an infrared radiation absorber comprising an anionic chromophore having a net negative charge or an acidic group; and optionally a polymer binder different from all (a), (b), and (c), all of which are described in more detail below. The infrared radiation-sensitive imageable layer of the machine-developable negative plate is usually the outermost layer in the precursor, but in some embodiments, an outermost cover layer (also called a top coating or oxygen barrier layer, and described below) may be present on top of it as the outermost layer.

[0066] Machine-developable negative infrared radiation-sensitive compositions (and machine-developable negative infrared radiation-sensitive imageable layers prepared therefrom) comprise (a) one or more radically polymerizable components, each containing one or more radically polymerizable groups that can be polymerized using radical initiation (and in some embodiments, two or more such groups). In some embodiments, the machine-developable negative infrared radiation-sensitive imageable layer comprises two or more radically polymerizable components having the same or different numbers of radically polymerizable groups in their respective molecules.

[0067] Useful radical-polymerizable components may contain one or more radical-polymerizable monomers or oligomers having one or more addition-polymerizable olefinic unsaturated groups (e.g., two or more such groups). Similarly, crosslinkable polymers having such radical-polymerizable groups may also be used. Oligomers or prepolymers may be used, such as urethane acrylates and urethane methacrylates, epoxide acrylates and epoxide methacrylates, polyester acrylates and polyester methacrylates, polyether acrylates and polyether methacrylates, and unsaturated polyester resins. In some embodiments, the radical-polymerizable component comprises a carboxyl group.

[0068] One or more free radical polymerizable components may have sufficiently large molecular weights to enhance the mechanical properties of the machine-developable infrared radiation-sensitive imageable layer of the negative plate, and thus make the corresponding lithographic plate precursor suitable for shipment in typical packaging and for handling during normal prepress operations.

[0069] Numerous other radical-polymerizable components are known in the art and described in a considerable number of documents, including EP 1,182,033A1 (Fujimaki et al.) (starting from paragraph

[0170] ), U.S. Patents 6,309,792 (Hauck et al.), 6,569,603 (Furukawa), and 6,893,797 (Munnelly et al.), and U.S. Patent Application Publication 2009 / 0142695 (Baumann et al.).

[0070] The presence of one or more radically polymerizable components in the machine-developable negative lithography infrared radiation-sensitive imageable layer is typically at least 10% by weight or at least 20% by weight, and at most 50% by weight or at most 70% by weight, all based on the total dry weight of the machine-developable negative lithography infrared radiation-sensitive imageable layer.

[0071] The machine-developable negative lithography infrared-sensitive imageable layer used in this invention further comprises (b) an initiator composition that, in the presence of a suitable infrared radiation absorber, provides free radicals when the machine-developable negative lithography infrared-sensitive imageable layer is exposed to suitable imaging infrared radiation to initiate the polymerization of one or more radically polymerizable components.

[0072] Initiator compositions for infrared radiation-sensitive compositions and imageable layers include, but are not limited to, ononium salts, such as ammonium, iodonium, sulfonium, and phosphonium compounds described in detail in U.S. Patent Application Publication 2014 / 0047993 (mentioned above)

[0131] . Examples of ononium salts include triarylsulfonium (salt), diaryliodonium (salt), and diaryldiazo (salt), wherein the aryl group includes phenyl and naphthyl groups and may be substituted.

[0073] Onon salts can be obtained by combining an onon salt containing sulfonium or iodonium in the molecule with an onon salt in the molecule. The onon salt can be a polyvalent onon salt having at least two onon ion atoms covalently bonded in the molecule. Among polyvalent onon salts, those having at least two onon ion atoms in the molecule are useful, and those having sulfonium or iodonium cations in the molecule are particularly useful. Representative polyvalent onon salts are represented by the following formulas (6) and (7): In addition, the ononium salt described in paragraphs

[0033] to

[0038] of the specification of Japanese Patent Publication 2002-082429 [or U.S. Patent Application Publication 2002-0051934 (Ippei et al.)], or the iodonium borate complex described in U.S. Patent 7,524,614 (as stated above) may also be used.

[0074] Anions used in iodonium salts include, but are not limited to, ClO4. - PF6 - BF4 - SbF6 - CH3SO3 - CF3SO3 - C6H5SO3 - CH3C6H4SO3 - HOC6H4SO3 - ClC6H4SO3 - and the borate anion represented by the following structure (VII): B - (R 1 (R) 2 (R) 3 (R) 4 ) (VII) Where R 1 R 2 R 3 and R 4 Independently representing a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group (including halogen-substituted aryl groups), a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted cycloalkyl group, or a substituted or unsubstituted heterocyclic group, or R 1 R 2 R 3 and R 4 Two or more of the R atoms can be linked together to form a substituted or unsubstituted heterocycle with boron atoms, such a ring having up to seven carbon, nitrogen, oxygen, or sulfur atoms. In some embodiments, all R atoms... 1 R 2 R 3 and R 4 These are the same or different substituted or unsubstituted aryl groups, such as substituted or unsubstituted phenyl groups, or more likely, all of these groups are unsubstituted phenyl groups. In many embodiments, at least one of X1, X2, and X3 is a tetraarylborate anion containing the same or different aryl groups, or in particularly useful embodiments, one or more of (X1, X2, and X3) are tetraphenylborate anions, or X1, X2, and X3 are each tetraphenylborate anions.

[0075] The initiator composition is typically present in a machine-developable negative lithography infrared-sensitive imageable layer, and is sufficient to provide one or more polymerization initiators in amounts of at least 0.5% by weight, at least 2% by weight, or even at least 4% by weight, and up to and including 12% by weight, at or including 15% by weight, or at or including 20% ​​by weight, all based on the total dry weight of the machine-developable negative lithography infrared-sensitive imageable layer.

[0076] Additionally, the machine-developable infrared radiation-sensitive imageable layer further comprises (c) one or more infrared radiation absorbers, each containing anionic chromophores with a net negative charge or acidic groups, to provide the required infrared radiation sensitivity when imaging using a suitable imaging device that responds to digital information (e.g., a laser emitting infrared radiation). In other words, none of these one or more infrared radiation absorbers contains cationic chromophores with a net positive charge and no acidic groups, and none of these one or more infrared radiation absorbers has a net zero charge and no acidic groups.

[0077] (c) One or more infrared radiation absorbers may each further comprise one or more suitable counterions against anionic chromophores, as will be readily apparent to those skilled in the art.

[0078] Suitable infrared radiation absorbers are known in the art, which may be infrared radiation absorbing dyes containing anionic chromophores with the required net negative charge, including but not limited to those described in U.S. Patents 6,511,782 (Vermeersch et al.), 5,208,135 (Patel et al.), 7,368,215 (Munnelly et al.), 8,409,780 (Callant et al.), and 8,778,590 (Callant).

[0079] A particularly useful class (c) of infrared radiation absorbers according to the invention comprises one or more anionic chromophores represented by formula (II): Equation (II) in: Each X represents >S, >O, >NR, or >C(R)2; Each R 1 Alkyl groups that are optionally substituted; R 2 Represents hydrogen, halogen, -SR, -SO2R, -OR, or -NR2 groups; Each R 3 Independently representing hydrogen atoms, optionally substituted alkyl groups, -COO --COOR, -OR, -SR, -NR2, halogen atom, sulfonate group, or optionally substituted benzofused ring; - - - represents either a five-membered or six-membered carbon ring; Each R independently represents hydrogen, an optionally substituted alkyl group, or an optionally substituted aryl group; Each n is independently 0, 1, 2, or 3; and R 1 R 2 and R 3 At least one of them contains one or more of a sulfonate group, a sulfonic acid group, a carboxylate group, and a carboxylic acid group, sufficient to provide a net negative charge or an acidic group for formula (II).

[0080] In some implementation schemes, it is desirable that R 1 R 2 and R 3 At least one of them contains a carboxylate group to provide a net negative charge or an acidic group for formula (II).

[0081] The net negative charge on the anionic chromophore represented by formula (II) can be transmitted via the cation Z + To achieve equilibrium and form a neutral infrared radiation absorber. A suitable cation Z... + Including M as described in equation (I) + And ononium salts, such as the cations of diaryliodoonium salts as described above for the initiator composition (b).

[0082] The following shows specific examples of useful anionic infrared radiation absorbers (AIR) having chromophores represented by formula (II).

[0083] AIR-1 AIR-2 AIR-3 AIR-4 AIR-5 AIR-6 AIR-7 AIR-8 AIR-9 AIR-10 AIR-11 AIR-12 AIR-13 AIR-14 AIR-15 AIR-16 AIR-17 In the infrared radiation-sensitive imageable layer of the machine-developable negative lithography plate, (c) the total dry coverage of one or more radiation absorbers is at least 5 mg / m². 2 Or at least 10 mg / m 2 And at most including 100 mg / m 2 or up to and including 200 mg / m 2 .

[0084] Optionally, but desirable in many embodiments, the machine-developable negative lithography infrared-sensitive imageable layer further comprises one or more (d) polymer binders (or materials acting as polymer binders) for all materials in the indicated layer. Such polymer binders differ from all (a), (b), and (c) materials described above. These polymer binders are generally non-crosslinkable and non-polymerizable, and at least one of these polymer binders may be in particulate form.

[0085] Such (d) polymeric adhesives can be selected from a wide variety of polymeric adhesive materials known in the art, including polymers comprising repeating units having side chains comprising polyoxyethylene segments, such polymers are described, for example, those in U.S. Patent 6,899,994 (Huang et al.). Other useful (d) polymeric adhesives comprise two or more types of repeating units having different side chains comprising polyoxyethylene segments, as described, for example, in WO Publication 2015-156065 (Kamiya et al.). Some of such (d) polymeric adhesives may further comprise repeating units having cyano side groups, as described, for example, in U.S. Patent 7,261,998 (Hayashi et al.).

[0086] Some useful (d) polymeric adhesives may exist in particulate form, i.e., as discrete, non-agglomerated particles. The average particle size of such discrete particles may be at least 10 nm and up to and including 1500 nm, or typically at least 80 nm and up to and including 600 nm, and they are generally uniformly distributed within an infrared-sensitive imageable layer of a machine-developable negative lithography plate. For example, one or more useful (d) polymeric adhesives may exist as particles with an average particle size of at least 50 nm and up to and including 400 nm. The average particle size can be determined by various known methods, including measuring particles in an electron scanning microscope image and averaging a number of measurements.

[0087] (d) The polymer adhesive may also have a main chain comprising a plurality of (at least two) urethane segments and side groups comprising polyoxyethylene segments.

[0088] Other useful (d) polymeric adhesives may contain polymerizable groups, such as acrylate groups, methacrylate groups, vinyl aryl and allyl groups; and alkali-soluble groups, such as carboxylic acids. Some of these useful (d) polymeric adhesives are described in U.S. Patent Application Publication 2015 / 0099229 (Simpson et al.) and U.S. Patent 6,916,595 (Fujimaki et al.).

[0089] As determined by gel permeation chromatography (polystyrene standard), useful (d) polymeric adhesives typically have a weight-average molecular weight (Mw) of at least 2,000 and up to and including 500,000, or at least 20,000 and up to and including 300,000.

[0090] Based on the total dry weight of the machine-developable negative infrared radiation sensitive imageable layer, the total amount of polymer binder present in (d) of the machine-developable negative infrared radiation sensitive imageable layer may be at least 10% by weight or at least 20% by weight, and at most and including 50% by weight or at most and including 70% by weight.

[0091] Other polymeric materials known in the art (unlike the (d) polymeric adhesive) can be present in machine-developable infrared-sensitive imageable layers for negative lithography, and these polymeric materials are generally more hydrophilic or more hydrophobic than the (d) polymeric adhesive described above. Examples of such hydrophilic polymeric adhesives include, but are not limited to, cellulose derivatives, such as hydroxypropyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol with various degrees of saponification. More hydrophobic polymeric adhesives are less developable than the (d) polymeric adhesive described above and generally have an acid value of less than 20 mg KOH / g for all acidic groups with pKa below 7 and their corresponding salts.

[0092] Additional optional additives for machine-developable negative lithography infrared-sensitive imageable layers may include organic dyes or organic dye precursors and color developers as known in the art. Such optional additives may be used as printing colorants and may be present in an amount of at least 1% by weight and at most, including 10% by weight, based on the total dry weight of the machine-developable negative lithography infrared-sensitive imageable layer.

[0093] Other useful printing colorants are known in the art and may include azo dyes, triarylmethane dyes, cyanine dyes, and spironolactone or spironolactam colorants as described, for example, in U.S. Patent Application Publication 2009 / 0047599 (Horne et al.), as well as various printing chemicals described in U.S. Patent Application Publications 2021 / 0078350 (Viehmann et al.) and 2021 / 0302834 (Viehmann et al.), and U.S. Serial Nos. 17 / 685,570 (filed by Simpson et al. on March 3, 2022), 17 / 685,592 (filed by Simpson et al. on March 3, 2002), and 17 / 720,405 (filed by Hansmann et al. on April 14, 2022).

[0094] The machine-developable negative lithography infrared radiation sensitive imageable layer may include cross-linked polymer particles as described in, for example, U.S. Patents 8,383,319 (Huang et al.), 8,105,751 (Endo et al.), and 9,366,962 (Kamiya et al.), having an average particle size of at least 2 µm or at least 4 µm, and up to and including 20 µm.

[0095] Topcoat layer: Although in many embodiments of the inventive lithographic printing plate precursor, the machine-developable negative lithography infrared-sensitive imageable layer is the outermost layer, with no layer disposed thereon, it is possible for the inventive precursor to be designed to have a layer (also referred to in the art as a cover layer or top layer) disposed above (or directly on) the machine-developable negative lithography infrared-sensitive imageable layer (with no intermediate layer between these two layers). When present, this cover layer is typically the outermost layer of the precursor and can be hydrophilic or hydrophobic.

[0096] The topcoat layer may contain one or more film-forming water-soluble polymeric adhesives, in an amount of at least 60% by weight and at most, including 100% by weight, based on the total dry weight of the hydrophilic topcoat layer. Such film-forming water-soluble (or hydrophilic) polymeric adhesives may include modified or unmodified polyvinyl alcohol having a saponification degree of at least 30%, at least 75%, at least 90%, and at most, including 99.9%.

[0097] It can be administered at a rate of at least 0.1 g / m 2 Or at least 0.15 g / m 2 And at most including 2.5 g / m 2 But less than 4 g / m 2 The dry coating coverage is used to provide the topcoat. In some embodiments, the dry coating coverage is as low as 0.1 g / m². 2 And at most including 1.5g / m 2 Or at least 0.1 g / m 2 And at most including 0.9 g / m 2 This results in a relatively thin outer layer.

[0098] Preparation of lithographic printing plate precursor The inventive lithographic printing plate precursor can be provided in the following ways. A machine-developable negative lithography infrared-sensitive imageable layer formulation containing the materials described above can be applied to the inventive aluminum-containing substrate (typically in the form of a continuous substrate roll or mesh) as described above, using any suitable equipment and procedures such as spin coating, doctor blade coating, gravure coating, die coating, slot coating, bar coating, wire rod coating, roller coating, or extrusion hopper coating. The machine-developable negative lithography infrared-sensitive imageable layer formulation can also be applied to a suitable inventive aluminum-containing substrate by spraying. Typically, once the formulation is applied with a suitable wet coverage, it is dried in a manner known in the art to provide the desired dry coverage as indicated below, thereby providing an infrared-sensitive continuous article of any suitable form (e.g., a mesh), from which individual precursors can be prepared using known manufacturing methods.

[0099] The manufacturing process typically involves mixing various components required by a special machine-developable negative lithography infrared radiation-sensitive imageable layer chemistry in a suitable organic solvent or a mixture thereof, and removing the solvent by evaporation under suitable drying conditions.

[0100] After proper drying, the dry coverage of the machine-developable negative lithography infrared radiation-sensitive imageable layer on the invention substrate is typically at least 0.1 g / m². 2 Or at least 0.4 g / m 2 And at most including 2 g / m 2 or at most including 4 g / m2 However, other dry coverage amounts may be used as needed.

[0101] Under actual manufacturing conditions, the result of these coating operations is a continuous web or roll of infrared radiation-sensitive lithographic printing plate precursor material having a machine-developable negative lithography infrared radiation-sensitive imageable layer disposed on the aluminum-containing substrate of the invention described above, and any optional layer (as indicated above).

[0102] Imaging (exposure) conditions During use, depending on the infrared radiation absorber present in the machine-developable infrared-sensitive imageable layer of the negative lithography plate, the lithographic printing plate precursor of the present invention can be exposed in-machine to a suitable exposure infrared radiation source. For example, the lithographic printing plate precursor can be imaged using an infrared laser that emits significant radiation in the range of at least 750 nm and up to and including 1400 nm, or at least 800 nm and up to and including 1250 nm. Such image-dependent exposure results in providing exposed and unexposed areas in the exposed, machine-developable infrared-sensitive imageable layer of the negative lithography plate.

[0103] Imaging can be performed using imaging or exposure to infrared radiation from a laser (or an array of such lasers) that generates infrared radiation. Imaging can also be performed simultaneously using imaging infrared radiation at multiple wavelengths, if necessary. Due to the reliability and low maintenance of diode laser systems, the laser used to expose the precursor of the invention is typically a diode laser, but other lasers such as gas lasers or solid-state lasers can also be used. The combination of power, intensity, and exposure time used for infrared radiation imaging will be readily apparent to those skilled in the art.

[0104] Depending on the sensitivity of the infrared-sensitive imageable layer in the machine-developable negative lithography, the infrared imaging energy can be at least 30 mJ / cm². 2 And at most including 500 mJ / cm 2 And typically at least 50 mJ / cm 2 And at most including 300 mJ / cm 2 .

[0105] Washing (developing) and printing After infrared image exposure, the exposed precursor, which has exposed and unexposed areas in the machine-developable radiation-sensitive imageable layer, can be machine-washed in a suitable manner to remove the unexposed areas and any masking layer (if present), leaving the fully hardened exposed areas.

[0106] For example, lithographic printing inks, dampening solutions, or a combination of lithographic printing inks and dampening solutions can be used to make the inventive precursor machine-developable. In such embodiments, the imaged, machine-developable negative lithographic printing plate precursor according to the invention can be mounted on a printing press, and then the printing operation can begin. During the preparation of the initial print run, unexposed areas in the machine-developable negative lithographic imageable layer are removed by using a suitable dampening solution, lithographic printing ink, or a combination of both.

[0107] In a typical sheet-fed printing press, the dampening rollers are first engaged and dampening solution is supplied to the mounted imaging precursor, causing the exposed, machine-developable infrared-sensitive imageable layer of the negative to swell, at least in the unexposed areas. After several rotations, the inking rollers are engaged, and they supply lithographic ink to cover the entire printing surface of the lithographic plate. Typically, within 5 to 20 rotations after the inking rollers are engaged, printing paper is supplied to remove material from the unexposed areas of the machine-developable infrared-sensitive imageable layer of the negative, as well as from the blanket cylinder (if present), using the resulting ink-dampening emulsion.

[0108] The present invention provides at least the following embodiments, either individually or in any suitable combination: 1. A lithographic printing plate precursor, comprising: Aluminum-containing substrates with hydrophilic surfaces, and An infrared radiation-sensitive imaging layer for negative lithography, which is machine-developable and can be placed on the hydrophilic surface of an aluminum-containing substrate. The aluminum-containing substrate includes: An aluminum plate with a ground and etched surface; An alumina inner layer is disposed on the ground and etched surface, the alumina inner layer having an average dry thickness (T) of at least 300 nm and at most including 3000 nm. i ), and contains many average internal micropore diameters (D i Micropores less than or equal to 11 nm, wherein the inner layer of alumina contains aluminum sulfate; An outer layer of alumina is disposed above the inner layer of alumina, and the outer layer of alumina contains a number of average external micropores with a diameter (D). o The external micropores are at least 12 nm and at most 50 nm in size, and have an average dry thickness (T) of at least 20 nm and at most 650 nm. o );as well as A hydrophilic layer disposed on the outer layer of alumina, wherein the hydrophilic layer comprises: (1) one or more phosphorus-containing compounds having a C1 dry coverage and represented by the following formula (I): Formula (I) Where n is 0 or an integer from 1 to 10, and -OM represents -OH or -O. - M + And M + It is a monovalent cation; and optionally (2) one or more hydrophilic polymers having a C2 dry coverage in the presence, (1) The C1 dry coverage of one or more phosphorus-containing compounds is at least 50 mg / m³. 2 And at most including 300 mg / m 2 And when (2) one or more hydrophilic polymers are present, the ratio of C1 dry coverage to C2 dry coverage is at least 11:9; and The machine-developable negative lithography infrared radiation-sensitive imageable layer comprises the following components (a) to (c) and optional component (d): (a) One or more components that are free radical polymerizable; (b) An initiator composition that provides free radicals when a machine-developable infrared-sensitive imageable layer of a negative plate is exposed to imaging infrared radiation; (c) One or more infrared radiation absorbers comprising anionic chromophores having a net negative charge or an acidic group; and optionally... (d) One or more polymeric adhesives that are all different from all components (a), (b) and (c).

[0109] 2. The lithographic printing plate precursor of implementation scheme 1, wherein the C1 dry coverage is at least 75 mg / m². 2 And at most including 200 mg / m 2 .

[0110] 3. The lithographic printing plate precursor of embodiment 1 or 2, wherein the ratio of C1 dry coverage to C2 dry coverage is at least 11:9 and at most and includes 30:1, wherein (2) one or more hydrophilic polymers are present in the hydrophilic layer.

[0111] 4. A lithographic printing plate precursor of any of the embodiments 1-3, wherein (c) one or more infrared radiation absorbers are present at a concentration of at least 5 mg / m³. 2 And at most including 200 mg / m 2 The dry coverage exists in the infrared radiation-sensitive imageable layer of the negative plate that can be developed in the machine.

[0112] 5. A lithographic printing plate precursor of any of embodiments 1-4, wherein (2) one or more hydrophilic polymers are present in the hydrophilic layer, and (2) one or more hydrophilic polymers include hydrophilic polymers comprising repeating units of: repeating units comprising a salt or ester of a carboxylic acid, phosphonic acid, phosphate group, or any of these acids; and optionally repeating units comprising an amide group.

[0113] 6. A pre-printing plate of any of the methods described in Implementation Scheme 1-5, wherein M + It is independently selected from proton, sodium cation, potassium cation, ammonium cation, alkylammonium cation, dialkylammonium cation, trialkylammonium cation and tetraalkylammonium cation, wherein each alkyl group may optionally be substituted.

[0114] 7. A lithographic printing plate precursor of any of embodiments 1-6, wherein the -OM group is selected such that one or more phosphorus-containing compounds represented by formula (I) exhibit a pH of at least 1 and at most and including 10 when dissolved in an aqueous solution containing 5% by weight of one or more phosphorus-containing compounds represented by formula (I).

[0115] 8. A lithographic printing plate precursor of any of the embodiments 1-7, wherein the anionic chromophore having a net negative charge or acidic group is represented by the following formula (II): Equation (II) in: Each X represents >S, >O, >NR, or >C(R)2; Each R 1 Alkyl groups that are optionally substituted; R 2 Represents hydrogen, halogen, -SR, -SO2R, -OR, or -NR2 groups; Each R 3 Independently representing hydrogen atoms, optionally substituted alkyl groups, -COO - -COOR, -OR, -SR, -NR2, halogen atom, sulfonate group, or optionally substituted benzofused ring; - - - represents either a five-membered or six-membered carbon ring; Each R independently represents hydrogen, an optionally substituted alkyl group, or an optionally substituted aryl group; Each n is independently 0, 1, 2, or 3; and R 1 R 2 and R 3 At least one of them contains a sulfonate group, a carboxylate group, or both a sulfonate group and a carboxylate group, to provide a net negative charge or an acidic group for formula (II).

[0116] 9. The lithographic printing plate precursor as described in Implementation Scheme 8, wherein R 1 R 2 and R 3 At least one of them contains a carboxylate group to provide a net negative charge or an acidic group for formula (II).

[0117] 10. A lithographic printing plate precursor of any of embodiments 1-9, wherein the alumina outer layer has an average dry thickness (T) of at least 50 nm. o Furthermore, the outer layer of alumina is directly disposed on the inner layer of alumina; the average dry thickness (T) of the inner layer of alumina i The internal micropore diameter is at least 500 nm, and the average internal micropore diameter (D) is... i The diameter of the external micropore is less than or equal to 11 nm and less than the average external micropore diameter (D). o ).

[0118] 11. A lithographic printing plate precursor of any of embodiments 1-10, wherein the aluminum-containing substrate further comprises an alumina intermediate layer disposed between an alumina inner layer and an alumina outer layer, wherein the alumina intermediate layer has an average dry thickness (T) of at least 60 nm and at most including 300 nm. m ), and contains many average intermediate micropore diameters (D m ) is at least 20 nm and at most includes 60 nm of intermediate micropores, wherein D m Greater than D o D o Greater than D i And the average dry thickness of the outer layer of alumina (T) o (less than 150 nm)

[0119] 12. A lithographic printing plate precursor of any of embodiments 1-11, wherein the machine-developable negative plate infrared radiation sensitive layer further comprises (d) one or more polymer binders, wherein at least one is in particulate form.

[0120] 13. Any of the lithographic printing plate precursors in Implementation Scheme 1-12, wherein the infrared radiation-sensitive imageable layer of the negative plate that can be developed in a machine is the outermost layer.

[0121] 14. A lithographic printing plate precursor of any of embodiments 1-13, wherein (2) one or more hydrophilic polymers are present, and the hydrophilic polymer comprises repeating units containing one or more of carboxylic acid groups, carboxyl salts or carboxylic ester groups, the repeating units comprising at least 50 mol of all repeating units.

[0122] 15. A lithographic printing plate precursor of any of embodiments 1-14, wherein (2) one or more hydrophilic polymers are present, and the hydrophilic polymer comprises repeating units containing repeating units of carboxylic acid, phosphonic acid or phosphate groups; and repeating units containing amide groups.

[0123] 16. A method for providing a lithographic printing plate, comprising: The lithographic printing plate precursor of any of the embodiments 1-15 is exposed to imaging infrared radiation according to the image to form an imageable layer with exposed and unexposed areas exposed to the infrared radiation according to the image, and Using lithographic printing ink, dampening solution, or both, unexposed areas are removed from the imageable layer exposed by infrared radiation to form a lithographic printing plate.

[0124] 17. A method for preparing a lithographic printing plate precursor of any of embodiments 1-15, comprising, in sequence: A) Provide aluminum plates with surfaces that have been electrochemically or mechanically ground and etched; B) A first anodizing treatment is applied to the aluminum-containing plate to form an aluminum oxide outer layer on the surface that has been electrochemically or mechanically ground and etched. The aluminum oxide outer layer contains a number of average external micropores with a diameter (D). o The external micropores are at least 12 nm and at most 50 nm in size, and have an average dry thickness (T) of at least 20 nm and at most 650 nm. o ); C) Rinse the outer layer of alumina; D) Applying additional anodizing treatment to the aluminum-containing plate using sulfuric acid to form an inner aluminum oxide layer beneath the outer aluminum oxide layer, the inner aluminum oxide layer having an average dry thickness (T) of at least 300 nm and at most including 3000 nm. i ), and contains many average internal micropore diameters (D i The micropores are less than or equal to 11 nm, wherein the inner layer of alumina contains aluminum sulfate; E) Rinse the outer and inner layers of alumina; F) A hydrophilic layer is provided above the alumina outer layer, wherein the hydrophilic layer comprises: (1) one or more phosphorus-containing compounds having a C1 dry coverage and represented by the following formula (I): Formula (I) Where n is 0 or an integer from 1 to 10, and -OM represents -OH or -O. - M + And M +It is a monovalent cation; and optionally (2) one or more hydrophilic polymers having a C2 dry coverage in the presence, (1) The C1 dry coverage of one or more phosphorus-containing compounds is at least 50 mg / m³. 2 And at most including 300 mg / m 2 And when (2) one or more hydrophilic polymers are present, the ratio of C1 dry coverage to C2 dry coverage is at least 11:9; and G) Form an infrared-sensitive imageable layer on top of the alumina outer layer for machine development of negative plates. The machine-developable negative lithography infrared radiation-sensitive imageable layer comprises the following components (a) to (c) and optional component (d): (a) One or more components that are free radical polymerizable; (b) An initiator composition that provides free radicals when a machine-developable infrared-sensitive imageable layer of a negative plate is exposed to imaging infrared radiation; (c) One or more infrared radiation absorbers comprising anionic chromophores having a net negative charge or an acidic group; and optionally... (d) One or more polymeric adhesives that are all different from all components (a), (b) and (c).

[0125] 18. The method of embodiment 17, wherein phosphoric acid is used for the first anodizing treatment.

[0126] 19. The method of embodiment 17 or 18, further comprising between step C) and step D): C') A second anodizing treatment is applied to the aluminum-containing plate to form an aluminum oxide intermediate layer under the aluminum oxide outer layer, the aluminum oxide intermediate layer having an average dry thickness (T) of at least 60 nm and at most including 300 nm. m ), and contains many average intermediate micropore diameters (D m ) is at least 20 nm and at most includes 60 nm of intermediate micropores, wherein D m Greater than D o D o Greater than D i And the average dry thickness of the outer layer of alumina (T) o (less than 150 nm, and) C”) Rinse the outer and middle layers of alumina, and The additional anodizing process in step D) is a third anodizing process used to form an inner layer of aluminum oxide under the intermediate layer of aluminum oxide.

[0127] 20. The method of embodiment 17, wherein (2) one or more hydrophilic polymers are present in the hydrophilic layer, and the method comprises a hydrophilic polymer containing repeating units of: repeating units containing carboxylic acid, phosphonic acid or phosphate groups; and optionally repeating units containing amide groups.

[0128] 21. The method of embodiment 17, wherein (2) one or more hydrophilic polymers are present in the hydrophilic layer, and the ratio of C1 dry coverage to C2 dry coverage is at least 11:9 and at most and includes 30:1.

[0129] The following embodiments are provided to illustrate the practice of the invention, and these embodiments are not intended to be limiting in any way.

[0130] Invention Examples 1-16 and Comparative Examples 1-8: Type A and Type B aluminum-containing substrates for preparing infrared radiation-sensitive offset printing plate precursors for negative lithography in the inventive and comparative examples are prepared according to the general method described above.

[0131] Type A support: This aluminum-containing support is prepared as described in Invention Example 1 of U.S. Patent 10,363,734 (as stated above). Therefore, the Type A support has an inner aluminum oxide layer and an outer aluminum oxide layer.

[0132] Type B support: This aluminum-containing support is prepared in the manner described in Type 3 aluminum-containing substrate (or "support") as in U.S. Serial No. 17 / 189,497, filed March 2, 2021 (now published as U.S. Patent Application 2022 / 0194112A1 (mentioned above)). Therefore, the Type B support has an inner aluminum oxide layer, an intermediate aluminum oxide layer, and an outer aluminum oxide layer.

[0133] Synthesis of copolymers used for the hydrophilic layer: Polymer 1 (which is a copolymer derived from vinylphosphonic acid and acrylamide (molar ratio of 1:9)) was prepared as follows: 3500 g of ethanol was charged into a 10 L reaction vessel equipped with a condenser and heated at 70 °C. 231.1 g of vinylphosphonic acid monomer and 1368.9 g of acrylamide monomer were mixed into 1000 g of ethanol, and 52 g of commercially available azobisisobutyronitrile (AIBN) polymerization initiator was dissolved in the monomer mixture. This AIBN-containing monomer mixture was then added dropwise to the 10 L reaction vessel over a 4-hour process at 70 °C. After this addition, the resulting reaction mixture was maintained at 70 °C for 2 hours and then cooled to room temperature. The resulting polymer 1 copolymer was precipitated as a white powder, separated by filtration, and washed with 1 L of ethanol. The polymer yield was determined to be 1550 g.

[0134] Preparation of hydrophilic layer formulation: Prepare hydrophilic layer formulations for use in various working examples using the components described in Table I below.

[0135] Table I: Hydrophilic Layer Formulation Table I (continued) Table I (continued) ACUMER TM Polymer 1000 is an aqueous solution (50 wt%) of polyacrylic acid, obtained from Dow Chemical Company.

[0136] Takesurf TM D-410-GL is a leveling agent obtained from TAKEMOTO OIL&FAT CO., LTD.

[0137] Using a wire-coated bar, at 20 g / m 2 The wet coverage was determined by coating the hydrophilic layer formulations shown in Table I onto either the Type A or Type B support sample. The resulting aluminum-containing substrates were then subjected to a wet coating process at 80°C. o Dry at C for 2 minutes. The dry coverage of each dried hydrophilic layer is shown in Table I above.

[0138] Preparation of infrared radiation-sensitive precursors for machine-developable negative lithography: The coating formulations MC-1, MC-2, and MC-3 for machine-developable negative lithography infrared radiation-sensitive imageable layers were prepared using the components and amounts shown in Table II below. The formulations were dissolved or dispersed at a total solids content of 5% by weight in a coating solvent mixture of 35% by weight n-propanol, 20% by weight 2-methoxypropanol, 35% by weight 2-butanone, and 10% by weight water.

[0139] The raw materials identified in Table II below are available from one or more commercial sources of chemicals or can be prepared using known synthetic methods and starting materials. Other materials are described in Table III below.

[0140] Table II Table III These formulations were coated onto an aluminum-containing substrate containing a hydrophilic layer using a wire-wound coating rod, and then at 80°C. o Dry at C for 2 minutes to provide machine-developable negative lithography infrared radiation-sensitive image recording layers, each having a concentration of 1 g / m². 2 The dry coverage. The resulting lithographic printing plate precursor is shown in Table IV below.

[0141] Table IV Table IV – Continued Using a Kodak Magnus 800 imagesetter and 150 mJ / cm in the solid area. 2 The exposure energy enables the imaging of each lithographic printing plate precursor identified above.

[0142] The following evaluation is performed on each imaging precursor or its corresponding unimaged precursor.

[0143] In-machine developability (DOP): As indicated above, each lithographic printing plate precursor was imaged and then mounted on a Roland R-201 printing press for in-machine development. The press was supplied with dampening solution [Presarto WS 100 (sold by DIC Graphics) / isopropyl alcohol / water 1 / 1 / 98 (volume ratio)], an S-7400 blanket (Kin-yo-sha), OK top-coated matte N-grade paper (Oji paper) as printing paper, and lithographic ink (Fusion G Magenta N sold by DIC Graphics), and printing was carried out at a rate of 9,000 sheets / hour. In-machine development capability was evaluated by the number of sheets (or print runs) from which no ink transfer was subsequently observed in the unimaged areas.

[0144] DOP was evaluated using the following two types of lithographic printing plates. Immediately after manufacturing, samples of each lithographic printing plate precursor were wrapped in light-shielding paper and stored at 25°C for 7 days (in the case of 'NK7'). Additionally, samples of each lithographic printing plate precursor were stored at 40°C and 80% RH in a commercially available ETAC FX-430 humidity chamber for 7 days (in the case of 'HT7').

[0145] In this evaluation, DOP with fewer than 50 sheets (prints) is preferred, and DOP with more than 100 sheets (prints) is unacceptable for this printing press condition. The smaller the difference in quantity between DOP identified as NK7 and DOP identified as HT7, the better the stability of the precursor over time after manufacturing.

[0146] Ozone-free printing plate durability: As described above, each lithographic printing plate precursor was imaged, and the resulting imaged precursors were mounted on a Komori S-26 printing press at 8,000 rpm. The printing plate durability was evaluated using a mixture of 1% K701 (DIC Graphics) and 10% isopropyl alcohol in water as dampening solution, S-7400 (Kin-yo-sha) blanket, OK top-coated matte N-grade paper (Oji paper) as printing paper, and K Magenta N-grade lithographic printing ink (DIC Graphics).

[0147] As the number of printed sheets (copies or print runs) increases through continuous printing, the infrared-sensitive imaging layer of the offset printing plate, which is machine-developable, gradually wears down, and its ink receptivity deteriorates. Consequently, the ink density on the printed paper decreases. Plate durability is defined as the number of copies (or print runs) required when the reflectance density of the solid areas on the printed paper decreases to 90% of its initial value. The greater the number of copies (or print runs) at which this deterioration occurs, the better the plate durability.

[0148] Printing plate durability with ozone exposure: Prior to imaging, each lithographic printing plate precursor was exposed to a controlled amount of ozone in a commercially available ETAC FX-430 humidity chamber, where the ozone concentration was controlled at 1 ppm and the chamber temperature was controlled at 25°C. o C. Use the following equipment to control ozone concentration: Kotohira portable ozone generator KPO-T01 as an ozone source; The Kanomax Gasmaster Model 2750 is an ozone monitor.

[0149] The ozone exposure time for each precursor was 6 hours, equivalent to an ozone exposure dose of 21,600 ppm∙s (where "ppm" is the ozone concentration per million parts per volume and "s" is an abbreviation for the time unit, seconds). After this ozone exposure, each precursor was imaged, and the printing plate durability was evaluated as described above for precursors not exposed to ozone.

[0150] The results of all these assessments are shown in Table V below.

[0151] Table V Table V – Continued As can be seen from the results shown in Table V, the precursors of Invention Examples 1 to 16, which contain anionic IR dyes and aluminum-containing substrates, exhibit desirable rapid in-machine development and small DOP differences compared to the imaging precursors labeled NK7 and HT7. These invention precursors also exhibited long imaging plate durability regardless of whether the unimaged precursors were exposed to ozone.

[0152] Although the precursors of Comparative Examples 1, 4, and 7 contain anionic IR dyes, they contain aluminum-containing substrates outside the scope of this invention because the dry coverage of phosphoric acid in the hydrophilic layer is greater than 300 mg / m². 2 They exhibited desirable rapid in-machine development of the imaging precursor labeled NK7 and the imaging precursor labeled HT7, as well as small DOP differences. Regardless of whether the unimaged precursor was exposed to ozone, these comparative precursors all exhibited poor plate durability.

[0153] Although the precursors of Comparative Examples 2, 3, 5, and 8 contain anionic IR dyes, they contain aluminum-containing substrates outside the scope of this invention because the dry coverage of phosphoric acid in the hydrophilic layer is less than 50 mg / m². 2 Regardless of whether the unimaged precursors were exposed to ozone, they all exhibited long plate durability, but they exhibited extremely slow HT7 post-development and a large DOP gap. It is believed that this extremely slow HT7 post-development is due to the interaction between the anionic chromophores of the infrared radiation absorber in the infrared-radiation-encapsulating layer of the imaged negative during the storage of the precursors under HT7 conditions and the aluminum ions (Al) of aluminum sulfate released from the anode layer of the substrate. 3+ The formation of salts between them is caused by salt.

[0154] Comparative Example 6's precursor contains a cationic dye and an aluminum-containing substrate according to the invention. However, while the precursor exhibits desirable rapid in-machine development for cases identified as NK7 and for cases identified as HK7, as well as a small DOP gap, and exhibits long plate durability if the unimaged precursor is not exposed to ozone, it exhibits poor plate durability if these precursors are exposed to ozone before imaging.

Claims

1. A lithographic printing plate precursor, comprising: Aluminum-containing substrates with hydrophilic surfaces, and An infrared radiation-sensitive imageable layer for negative lithography, disposed above the hydrophilic surface of the aluminum-containing substrate, is available for machine development. The aluminum-containing substrate comprises: An aluminum plate with a ground and etched surface; An alumina inner layer disposed on the ground and etched surface, the alumina inner layer having an average dry thickness (T) of at least 300 nm and at most including 3000 nm. i ), and contains many average internal micropore diameters (D i Micropores less than or equal to 11 nm, wherein the inner layer of alumina contains aluminum sulfate; An outer layer of alumina is disposed above the inner layer of alumina, the outer layer of alumina comprising a plurality of average external micropore diameters (D). o The external micropores are at least 12 nm and at most 50 nm in size, and have an average dry thickness (T) of at least 20 nm and at most 650 nm. o );and A hydrophilic layer disposed on the outer layer of the alumina, wherein the hydrophilic layer comprises: (1) one or more phosphorus-containing compounds having a C1 dry coverage and represented by the following formula (I): Formula (I) Where n is 0 or an integer from 1 to 10, and -OM represents -OH or -O. - M + And M + It is a monovalent cation; and optionally (2) one or more hydrophilic polymers having a C2 dry coverage in the presence, The C1 dry coverage of one or more phosphorus-containing compounds in (1) is at least 50 mg / m³. 2 And at most including 300 mg / m 2 And when one or more of the hydrophilic polymers mentioned in (2) are present, the ratio of the dry coverage of C1 to the dry coverage of C2 is at least 11:9; and The machine-developable negative lithography infrared radiation-sensitive imageable layer comprises the following components (a) to (c) and optional component (d): (a) One or more components that are free radical polymerizable; (b) An initiator composition that provides free radicals when the machine-developable infrared-sensitive imageable layer of the negative lithography is exposed to imaging infrared radiation; (c) One or more infrared radiation absorbers comprising anionic chromophores having a net negative charge or an acidic group; and optionally... (d) One or more polymeric adhesives that are all different from all components (a), (b) and (c).

2. The lithographic printing plate precursor of claim 1, wherein the C1 dry coverage is at least 75 mg / m². 2 And at most including 200 mg / m 2 .

3. The lithographic printing plate precursor of claim 1 or 2, wherein one or more hydrophilic polymers are present in the hydrophilic layer, and the ratio of the C1 dry coverage to the C2 dry coverage is at least 11:9 and at most and includes 30:

1.

4. The lithographic printing plate precursor according to claim 1 or 2, wherein one or more infrared radiation absorbers are present at a concentration of at least 10 mg / m³. 2 And at most including 200 mg / m 2 The dry coverage exists in the infrared radiation-sensitive imageable layer of the negative plate that can be developed in the machine.

5. The lithographic printing plate precursor of claim 1 or 2, wherein one or more hydrophilic polymers of (2) are present in the hydrophilic layer, and the one or more hydrophilic polymers of (2) comprise hydrophilic polymers containing repeating units of: repeating units containing a salt or ester of a carboxylic acid, phosphonic acid, phosphate group, or any of these acids; and optionally repeating units containing an amide group.

6. The lithographic printing plate precursor according to claim 1 or 2, wherein M + It is independently selected from proton, sodium cation, potassium cation, ammonium cation, alkylammonium cation, dialkylammonium cation, trialkylammonium cation and tetraalkylammonium cation, wherein each alkyl group may optionally be substituted.

7. The lithographic printing plate precursor of claim 1 or 2, wherein the -OM group is selected such that the phosphorus-containing compound (1) represented by formula (I) exhibits a pH of at least 1 and at most and including 10 when dissolved in an aqueous solution containing 5% by weight of the phosphorus-containing compound (1) represented by formula (I).

8. The lithographic printing plate precursor of claim 1 or 2, wherein the anionic chromophore having a net negative charge or acidic group is represented by the following formula (II): Equation (II) in: Each X represents >S, >O, >NR, or >C(R)2; Each R 1 Alkyl groups that are optionally substituted; R 2 Represents hydrogen, halogens, -SR, -SO2R, -OR, or -NR2 groups; Each R 3 Independently representing hydrogen atoms, optionally substituted alkyl groups, -COO - -COOR, -OR, -SR, -NR2, halogen atom, sulfonate group, or optionally substituted benzofused ring; - - - represents either a five-membered or six-membered carbon ring; Each R independently represents hydrogen, an optionally substituted alkyl group, or an optionally substituted aryl group; Each n is independently 0, 1, 2, or 3; and R 1 R 2 and R 3 At least one of them contains a sulfonate group, a carboxylate group, or both a sulfonate group and a carboxylate group, to provide a net negative charge or an acidic group for formula (II).

9. The lithographic printing plate precursor of claim 8, wherein R 1 R 2 and R 3 At least one of them contains a carboxylate group to provide a net negative charge or an acidic group for formula (II).

10. The lithographic printing plate precursor of claim 1 or 2, wherein the alumina outer layer has an average dry thickness (T) of at least 50 nm. o The outer layer of alumina is directly disposed on the inner layer of alumina; the average dry thickness (T) of the inner layer of alumina... i The average internal micropore diameter (D) is at least 500 nm. i The diameter of the external micropore is less than or equal to 11 nm and less than the average external micropore diameter (D). o ).

11. The lithographic printing plate precursor of claim 1 or 2, wherein the aluminum-containing substrate further comprises an alumina intermediate layer disposed between the inner alumina layer and the outer alumina layer, wherein the alumina intermediate layer has an average dry thickness (T) of at least 60 nm and at most including 300 nm. m ), and contains many average intermediate micropore diameters (D m ) is at least 20 nm and at most includes 60 nm of intermediate micropores, wherein D m Greater than D o D o Greater than D i And the average dry thickness (T) of the outer layer of the alumina o (less than 150 nm) 12. The lithographic printing plate precursor of claim 1 or 2, wherein the machine-developable negative plate infrared radiation sensitive layer further comprises (d) one or more polymeric binders, wherein at least one is in particulate form.

13. The lithographic printing plate precursor of claim 1 or 2, wherein the machine-developable negative plate infrared radiation sensitive imageable layer is the outermost layer.

14. The lithographic printing plate precursor of claim 1 or 2, wherein one or more of the hydrophilic polymers of claim (2) are present, and wherein the hydrophilic polymer comprises repeating units of one or more of carboxylic acid groups, carboxyl salts or carboxylic ester groups, wherein the repeating units comprise at least 50 mol of all repeating units.

15. The lithographic printing plate precursor of claim 1 or 2, wherein one or more of the hydrophilic polymers of claim (2) are present, and wherein the hydrophilic polymer comprises repeating units containing repeating units of carboxylic acid, phosphonic acid or phosphate groups; and repeating units containing amide groups.

16. A method for providing a lithographic printing plate, comprising: The lithographic printing plate precursor of any one of claims 1-15 is exposed to imaging infrared radiation according to an image to form an imageable layer having exposed and unexposed areas exposed to image infrared radiation, and Using lithographic printing ink, dampening solution, or both, the unexposed areas are removed from the imageable layer exposed by infrared radiation to form a lithographic printing plate.

17. A method for preparing a lithographic printing plate precursor according to any one of claims 1-15, comprising, in sequence: A) Provide aluminum plates with surfaces that have been electrochemically or mechanically ground and etched; B) The aluminum-containing plate is subjected to a first anodizing treatment to form an aluminum oxide outer layer on the surface that has been electrochemically or mechanically ground and etched, the aluminum oxide outer layer comprising a plurality of average external micropore diameters (D). o The external micropores are at least 12 nm and at most 50 nm in size, and have an average dry thickness (T) of at least 20 nm and at most 650 nm. o ); C) Rinse the outer layer of the alumina; D) Apply an additional anodizing treatment to the aluminum-containing plate using sulfuric acid to form an inner aluminum oxide layer beneath the outer aluminum oxide layer, the inner aluminum oxide layer having an average dry thickness (T) of at least 300 nm and at most including 3000 nm. i ), and contains many average internal micropore diameters (D i The inner pores are less than or equal to 11 nm, wherein the inner alumina layer contains aluminum sulfate. E) Rinse the outer and inner layers of the alumina; F) A hydrophilic layer is provided above the alumina outer layer, wherein the hydrophilic layer comprises: (1) one or more phosphorus-containing compounds having a C1 dry coverage and represented by the following formula (I): Formula (I) Where n is 0 or an integer from 1 to 10, and -OM represents -OH or -O. - M + And M + It is a monovalent cation; and optionally (2) one or more hydrophilic polymers having a C2 dry coverage in the presence, The C1 dry coverage of one or more phosphorus-containing compounds in (1) is at least 50 mg / m³. 2 And at most including 300 mg / m 2 And when one or more of the hydrophilic polymers mentioned in (2) are present, the ratio of the dry coverage of C1 to the dry coverage of C2 is at least 11:9; and G) Form an infrared-sensitive imageable layer for negative lithography that can be machine-developed above the outer layer of alumina. The machine-developable negative lithography infrared radiation-sensitive imageable layer comprises the following components (a) to (c) and optional component (d): (a) One or more components that are free radical polymerizable; (b) An initiator composition that provides free radicals when the machine-developable infrared-sensitive imageable layer of the negative lithography is exposed to imaging infrared radiation; (c) One or more infrared radiation absorbers comprising anionic chromophores having a net negative charge or an acidic group; And optional (d) One or more polymeric adhesives that are all different from all components (a), (b) and (c).

18. The method of claim 17, wherein phosphoric acid is used for the first anodizing treatment.

19. The method of claim 17 or 18, further comprising between step C) and step D): C') A second anodizing treatment is applied to the aluminum-containing plate to form an aluminum oxide intermediate layer under the aluminum oxide outer layer, the aluminum oxide intermediate layer having an average dry thickness (T) of at least 60 nm and at most including 300 nm. m ), and contains many average intermediate micropore diameters (D m ) is at least 20 nm and at most includes 60 nm of intermediate micropores, wherein D m Greater than D o D o Greater than D i And the average dry thickness (T) of the outer layer of the alumina o (less than 150 nm, and) The additional anodizing treatment in step D) is a third anodizing treatment used to form the inner layer of aluminum oxide under the intermediate layer of aluminum oxide.

20. The method of claim 17 or 18, wherein one or more hydrophilic polymers are present in the hydrophilic layer, and the hydrophilic polymer comprises repeating units containing repeating units of: repeating units containing carboxylic acid, phosphonic acid or phosphate groups; and optionally repeating units containing amide groups.

21. The method of claim 17 or 18, wherein one or more hydrophilic polymers are present in the hydrophilic layer, and the ratio of the C1 dry coverage to the C2 dry coverage is at least 11:9 and at most and includes 30:1.

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