Lithographic printing plates and instructions for use

Abstract

The negative type lithographic printing plate master has a negative type infrared-sensitive image recording layer having a) two or more free radical polymerizable components, b) an initiator composition capable of generating free radicals, and c) one or more infrared-absorbing cyanine dyes. a) The two or more free radical polymerizable components include a combination of urethane (meth)acrylate and polyester (meth)acrylate, which together constitute 75 to 100% by weight of all free radical polymerizable components. The weight ratio of urethane (meth)acrylate to polyester (meth)acrylate is 90:10 to 35:65 or less. The urethane (meth)acrylate contains one or more urethane bonds and at least four acrylic acid ester groups or methacrylic acid ester groups. Each of the one or more polyester (meth)acrylates does not contain a urethane bond and is represented by the following structure (I). These masters have low sensitivity to ambient ozone and allow infrared image formation and on-press development during lithographic printing.

Description

[Technical Field]

[0001] The present invention relates to an infrared-sensitive lithographic printing plate master capable of image formation using infrared light to provide an imaged lithographic printing plate. Such a master plate contains a crucial combination of free-radical polymerizable components to protect the infrared-absorbing cyanine dye from ambient ozone, thereby minimizing the reduction in on-press developability and print durability. The master plate of the present invention is negative type and, in particular, on-press developable. The present invention also relates to a method for providing a lithographic printing plate using these master plates after appropriate infrared image formation and development, particularly after on-press development. [Background technology]

[0002] Image forming systems, such as computer-to-plate (CTP) image forming systems, are known in the art and are used to record images on lithographic printing plates. Such plates typically include a substrate made of aluminum having a hydrophilic surface on which one or more radiative image-forming layers are disposed. These plates are used to manufacture lithographic printing plates having lithographic ink-receiving areas, known as image areas, on the hydrophilic surface of the substrate. When the surface of the printing plate is moistened with water and lithographic ink is applied, the hydrophilic areas retain water and repel the lithographic ink, while the lithographic ink-receiving image areas accept the lithographic ink and repel water. The lithographic ink is transferred to the surface of the material, possibly using a blanket roller, and an image is reproduced on the material.

[0003] Lithographic printing plates are considered to be either "positive" or "negative." Positive lithographic printing plates are designed to include one or more radiation-sensitive layers, and therefore, when image-like exposed to suitable radiation such as infrared light, the exposed areas of the layers become more easily soluble in alkaline solutions and can be removed during processing, leaving unexposed areas that accept lithographic inks for printing.

[0004] In contrast, negative type lithographic printing plates are designed to include a radiation-sensitive layer, and therefore, when exposed to appropriate radiation such as infrared light, the exposed areas of the layer harden and become resistant to removal during processing, while the unexposed areas remain removable during processing.

[0005] In the current state of technology in the lithographic printing industry, lithographic printing plates are typically exposed to image-forming radiation, such as infrared light, using a laser, within an imaging apparatus commonly known as a platesetter (for CTP imaging), before undergoing additional processing (developing) to remove unwanted material from the image-formed plate.

[0006] In recent years, there has been a growing demand in the lithographic printing industry for simplification in the production of lithographic printing plates, which involves on-press development ("DOP") using lithographic inks, dampening solutions, or both, to remove unexposed areas of the image recording layer. Therefore, the use of on-press developable lithographic plates is increasingly being adopted in the printing industry due to its numerous advantages, including reduced environmental impact, savings in processing chemicals and equipment footprint, and reduced operating and maintenance costs. After laser imaging, on-press developable plates can be directly loaded into the lithographic printing press.

[0007] Many of the positive and negative lithographic printing plates used in this industry are designed to be sensitive to near-infrared or infrared light (typically radiation with at least 800 nm). It has become particularly desirable for negative plates, such as press-developable plates, to be designed to contain cyanine dye compounds, especially those containing polymethine chains, as infrared-sensitive dyes.

[0008] However, many of such cyanine infrared-sensitive dyes have been found to be particularly vulnerable to attack by ambient ozone, especially when the compound is incorporated into one or more top layers of the original plate. As a result of such attacks, the original plate may lose its on-machine durability. These problems can be particularly severe when the original plate is stored for a long time before being exposed, processed (developed), and used in lithography.

[0009] U.S. Patent Application Publication No. 2019 / 0022993 (Igarashi et al.) describes using a filter specifically arranged inside or around an image forming apparatus (such as a plate setter) to remove ambient ozone and thereby reduce the effect of ozone on a negative lithographic printing plate original.

[0010] U.S. Patent Application Publication No. 2022 / 0072844 (Miyamoto et al., hereinafter referred to as U.S. Patent Application Publication ‘844) describes the progress in the art for improving the stability of such an original by including a predetermined ozone-blocking material in the negative lithographic printing plate original.

[0011] After extensive studies to find the problems caused by ambient ozone and to attempt various solutions to this problem, it has been found that further improvements beyond those described in U.S. Patent Application Publication ‘844 are desirable.

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

[0013] The present invention relates to a negative-type lithographic printing plate master comprising an aluminum-containing substrate and a negative-type infrared-sensitive image recording layer disposed on the aluminum-containing substrate, The negative infrared-sensitive image recording layer is a) Two or more free radical polymerizable components, b) an initiator composition capable of generating free radicals, and c) Contains one or more infrared absorbing cyanine dyes, a) comprising one or more urethane (meth)acrylates and one or more polyester (meth)acrylates, wherein two or more free radical polymerizable components together constitute at least 75% to 100% by weight of all free radical polymerizable components. The weight ratio of one or more urethane (meth)acrylates to one or more polyester (meth)acrylates is 90:10 to 35:65 or less. Each of the one or more urethane (meth)acrylates comprises one or more urethane bonds and at least four acrylic acid ester groups or methacrylic acid ester groups. Each of the one or more polyester (meth)acrylates does not contain a urethane bond and has the following structure (I): X-OC(=O)-LC(=O)-OY (I) [In the formula, L represents a single bond or carbon chain, and X and Y independently represent a hydrogen atom or an organic group represented by the following structure (II), however, X and Y cannot both be hydrogen atoms.] -A(R) n (II) In the formula, A represents an n+1 valent organic group, R represents a hydroxyl group, an acrylic acid ester group (CH2=CHC(=O)O-), or a methacrylic acid ester group (CH2=C(CH3)C(=O)O-), and n is an integer between 1 and 12, provided that not all R groups are hydroxyl groups. We provide negative-type lithographic printing plates.

[0014] In some embodiments of the present invention, the negative type lithographic printing plate master includes an aluminum-containing substrate comprising two or more aluminum oxide layers, and a negative type infrared-sensitive image recording layer disposed as the outermost layer on the aluminum-containing substrate. The negative-type infrared-sensitive image recording layer is a) Two or more free radical polymerizable components, b) An initiator composition that can generate free radicals and comprises an iodonium cation and a tetraarylborate anion, and c) Contains one or more infrared absorbing cyanine dyes, a) The two or more free radical polymerizable components include one or more urethane (meth)acrylates and one or more polyester (meth)acrylates, which together constitute at least 80% to 100% by weight of all free radical polymerizable components. The weight ratio of one or more types of urethane (meth)acrylate to one or more types of polyester (meth)acrylate is 75:25 to 50:50 or less. Each of the one or more urethane (meth)acrylates comprises one or more urethane bonds and at least four acrylic acid ester groups or methacrylic acid ester groups, and has the following structure (III): L'-[NH-C(=O)-O-X'] p (III) [In the formula, L' represents a p-valent linking group, where p is an integer of 2 or 3, and X' is represented by the following structure (IV), -A'(R') n’ (IV) In the formula, A' represents an n'+1 valent organic group, R' represents a hydroxyl group, an acrylic acid ester group [CH2=CHC(=O)O-], or a methacrylic acid ester group [(CH2=C(CH3)C(=O)O-] independently, and n' is an integer between 1 and 6, provided that not all R' groups are hydroxyl groups]. Each of the one or more polyester (meth)acrylates does not contain a urethane bond and has the following structure (I): X-OC(=O)-LC(=O)-OY (I) [In the formula, L represents a single bond, or a *CH2-CH2* group, a *CH=CH* group, and the groups Ia and Ib shown below: [ka] (Ia), and [ka] (Ib) (In the formula, * represents a connection point with the rest of structure (I)), and X and Y independently represent a hydrogen atom or an organic group represented by the following structure (II), however, X and Y cannot both be hydrogen atoms. -A(R) n (II) In the formula, A represents an n+1 valent organic group, R represents a hydroxyl group, an acrylic acid ester group (CH2=CHC(=O)O-), or a methacrylic acid ester group (CH2=C(CH3)C(=O)O-), and n is an integer between 1 and 12, provided that not all R groups are hydroxyl groups.

[0015] Furthermore, the present invention relates to a method for providing a lithographic printing plate, A) A step of exposing a negative type lithographic printing plate according to any one embodiment of the present invention to image-like light with image-forming infrared light to provide exposed regions and unexposed regions in a negative type infrared-sensitive image recording layer, and B) A process of removing unexposed areas in the negative-type infrared-sensitive image recording layer from the aluminum-containing substrate. This provides a method that includes [something].

[0016] The present invention overcomes the aforementioned problems caused by ambient ozone, namely a reduction in image formation sensitivity and on-press print durability, by a) selecting a critical combination of two or more free radical polymerizable components in critical amounts and weight ratios in a negative-type infrared-sensitive image recording layer. Unexpectedly, this selection in the negative-type infrared-sensitive image recording layer results in excellent resistance of the infrared-absorbing cyanine dye to decomposition in the presence of ambient ozone, and thus enables the printing press operator to maintain the desired image formation speed (image formation sensitivity) and other properties of the lithographic printing plate, such as the on-press print durability of the resulting lithographic printing plate.

[0017] Specifically, the above problem was solved by selecting a combination of one or more urethane (meth)acrylates and one or more polyester (meth)acrylates, with at least 75% by weight of all free radical polymerizable components in the negative-type infrared-sensitive image recording layer. The crucial presence of urethane (meth)acrylates improves print durability (print life as defined below), with or without exposure to ambient ozone, but their presence also tends to reduce on-press developability (DOP as defined below). By incorporating a specific amount of polyester (meth)acrylate in combination with urethane (meth)acrylates, on-press developability is improved while unexpectedly maintaining the desired print durability (print life) and other properties, even after exposure to ambient ozone. While other non-urethane (meth)acrylates are known to improve on-press developability, these non-urethane (meth)acrylates tend to make infrared-absorbing cyanine dyes vulnerable to degradation, and therefore, print durability and other properties may decrease when the unimaged master plate is exposed to ambient ozone. [Modes for carrying out the invention]

[0018] definition Unless otherwise indicated in the context, the terms “negative lithographic printing plate,” “plate,” and “IR-sensitive negative lithographic printing plate” are intended to be equivalent to embodiments of the present invention as used herein.

[0019] As used herein, the term “infrared-absorbing cyanine dye” refers to a cyanine dye compound or material that absorbs electromagnetic radiation in the near-infrared (near-IR) and infrared (IR) regions of the electromagnetic spectrum, and typically refers to a cyanine dye compound or material having an absorption maximum in the near-IR and IR regions.

[0020] As used herein, the terms “near-infrared region” and “infrared region” refer to radiation having wavelengths of at least 750 nm or greater. In most cases, these terms are used to refer to the electromagnetic spectrum region of at least 750 nm, and more preferably between at least 800 nm and 1400 nm.

[0021] As used herein, the term “ethylenically unsaturated polymerizable monomer” refers to a compound containing one or more ethylenically unsaturated (-C=C-) bonds that can be polymerized using free radical or acid-catalyzed polymerization reactions and conditions. This term is not intended to refer to a compound having only unsaturated -C=C- bonds that cannot be polymerized under such conditions.

[0022] Unless otherwise indicated, the term "weight %" refers to the amount of an ingredient or material relative to the total solids of a composition, formulation, or layer. Unless otherwise indicated, the percentage may be the same for the dry layer or the total solids of a formulation or composition.

[0023] As used herein, the terms “layer” or “coating” may consist of one arranged or coated layer, or a combination of several consecutively arranged or coated layers. Where a layer is considered infrared sensitive and negative, it is both sensitive to infrared light (as described above for “infrared absorbers”) and negative in the formation of a lithographic printing plate.

[0024] use The lithographic printing plates according to the present invention are useful for providing lithographic printing plates using a negative-type image-forming chemical reaction system present in one or more negative-type infrared-sensitive image recording layers. These lithographic printing plates are useful for lithographic printing during the printing operation. The lithographic printing plates can be manufactured according to the present invention using either on-press or off-press (developing) processing, as described below. The negative-type lithographic printing plates of the present invention are manufactured using the structure and components described below.

[0025] Planographic printing plate original plate The master plates according to the present invention can be formed by appropriately coating one or more negative-type infrared-sensitive image recording compositions, as described below, onto a suitable substrate (as described below) to form one or more negative-type infrared-sensitive image recording layers on the substrate. All of these master plates require the presence of the substrate described below.

[0026] substrate: A substrate used to manufacture a master plate according to the present invention generally has a hydrophilic image-forming surface or at least a surface that is more hydrophilic than (one or more) negative-type infrared-sensitive image recording layers placed thereon. The substrate generally includes an aluminum-containing support which may be made of raw aluminum or a suitable aluminum alloy conventionally used to manufacture lithographic printing plates, and therefore a more desirable substrate is the aluminum-containing substrate detailed below.

[0027] Aluminum-containing substrates can be processed using techniques known in the art, which include roughening the aluminum-containing support by physical (mechanical) granulation, electrochemical granulation, or chemical granulation, followed by one or more anodic oxidation treatments, or various rinsing operations as appropriate.

[0028] Each anodizing process is typically carried out using either phosphoric acid or sulfuric acid and conventional conditions to form a desired hydrophilic aluminum oxide (or anodic oxide) layer on an aluminum-containing support. There may be one aluminum oxide (anodic oxide) layer, or there may be multiple (two or more) aluminum oxide layers having multiple pores with pore openings of varying depths and shapes. Thus, such a process provides one or more anodic oxide layers beneath one or more negative-type infrared-sensitive image recording layers. Processes for controlling such pores and pore widths are described, for example, in U.S. Patent Publication No. 2013 / 0052582 (Hayashi), No. 2014 / 0326151 (Namba et al.), and No. 2018 / 0250925 (Merka et al.), as well as U.S. Patent No. 4,566,952 (Sprintschuik et al.), No. 8,789,464 (Tagawa et al.), No. 8,783,179 (Kurokawa et al.), and No. 8,978,555 (Kurokawa et al.), and European Patent No. 2,353,882 (Tagawa et al.). Teachings on providing separate aluminum oxide layers in an improved substrate by performing two consecutive anodizing treatments are described, for example, in U.S. Patent Publication No. 2018 / 0250925 (Merka et al.).

[0029] The anodized aluminum-containing support can be further processed to seal the anodic oxide pores, or to hydrophilize its surface, or both, using a post-treatment process known for anodic treatment, such as an aqueous solution of one or more hydrophilic substances or polymers such as poly(vinylphosphonic acid) (PVPA), vinylphosphonic acid copolymer, poly[(meth)acrylic acid] or its alkali metal salts, or (meth)acrylic acid copolymer or its alkali metal salts, a mixture of phosphate and fluoride salts, or sodium silicate. The post-treatment process material can also contain unsaturated double bonds to strengthen the adhesion between the treated aluminum oxide surface and the infrared exposure area of the negative infrared-sensitive image recording layer laminated thereon. Such unsaturated double bonds may be provided in a low molecular weight material or may be present in the side chains of a hydrophilic polymer.

[0030] In some embodiments, the hydrophilic layer contains one or more hydrophilic polymers in a dry coating amount of at least 0.0002 g / m 2 ~0.1 g / m 2 or less, or in an amount of at least 0.005 g / m 2 ~0.08 g / m 2 or less. The total dry coating amount of the hydrophilic layer can be at least 0.0002 g / m 2 ~0.25 g / m 2 or less. Generally, since the hydrophilic layer is disposed directly on the outer aluminum oxide layer, there is no intermediate layer. Since the outer aluminum oxide layer contains micropores, a part of the hydrophilic layer can be present inside such micropores and in the micropores under the outer aluminum oxide layer.

[0031] Particularly useful examples of such hydrophilic layers for the present invention include those described in US Patent Application Publication No. 2022-0118754 (Merka et al.) and US Patent Application No. 17 / 880,877 (published as US Patent Application Publication No. 2024 / 0061337).

[0032] In some embodiments, the hydrophilic layer further comprises a compound having one or more ethylenically unsaturated polymerizable groups and one or more -OM groups, at least one of which is directly bonded to a phosphorus atom, and having a molecular weight of less than 2000 daltons / mol or less than 1500 daltons / mol, where M represents a hydrogen, sodium, potassium, or aluminum atom.

[0033] A particularly useful example of such a hydrophilic layer for the present invention is the one described in U.S. Patent Application Publication No. 2022-0194112 (Obenauf et al.).

[0034] Negative type lithographic printing plate original The negative lithographic printing plates according to the present invention can be constructed using the following components and materials. Typically, each of these plates has an aluminum-containing substrate (as described above), on which one or more negative infrared-sensitive image recording layers are disposed, each of which includes a chemical reaction system suitable for negative infrared image formation and appropriate processing to facilitate the removal of unexposed areas of each negative infrared-sensitive image recording layer. In the case of certain negative lithographic printing plates, one negative infrared-sensitive image recording layer is present on the aluminum-containing substrate.

[0035] The infrared-sensitive composition according to the present invention (and the infrared-sensitive image recording layer produced from the composition) is designed in a "negative" form, a term known in the art of lithographic printing. Furthermore, the infrared-sensitive image recording layer may be designed in a specific combination of components to enable development using, for example, dampening solution, lithographic ink, or a combination of dampening solution and lithographic ink, in order to give the negative-type lithographic printing plate, after exposure, on-press developability.

[0036] One or more infrared image recording layers: The master plate can be formed by appropriately coating one or more negative infrared-sensitive compositions, as described below, onto a suitable substrate (as described above) to form one or more negative infrared-sensitive image recording layers on the substrate.

[0037] Generally, at least one negative infrared-sensitive image recording layer contains, as essential components, a) two or more free radical polymerizable components as described below, b) an initiator composition (described below) that can generate free radicals when the negative infrared-sensitive image recording layer is exposed to image-forming infrared light, and c) one or more infrared absorbers including at least one infrared-absorbing cyanine dye as described below. In some cases, there may be one or more non-free radical polymerizable polymer materials different from all of a) two or more free radical polymerizable components, b) the initiator composition, and c) the infrared-absorbing cyanine dye. All of these essential components and various optional components will be described in more detail below. The negative infrared-sensitive image recording layer may be the outermost layer of the master plate.

[0038] An essential component of one or more negative infrared-sensitive image recording layers is a) two or more free radical polymerizable components, the composition and amounts of two of which are critical to achieving the advantages described herein. a) Each of the two or more free radical polymerizable components comprises one or more free radical polymerizable groups that can be polymerized using free radical initiation during infrared exposure, and in many embodiments, each of these compounds comprises at least one acrylic acid ester group or methacrylic acid ester group, or further at least two or at least four acrylic acid ester groups or methacrylic acid ester groups.

[0039] a) At least one of the essential compounds of the two or more free radical polymerizable components should be a urethane (meth)acrylate. That is, this compound may be a urethane acrylate or a urethane methacrylate compound, meaning that both types of compounds may exist. Each urethane (meth)acrylate contains one or more urethane [-NHC(=O)O-] groups, or even two or more of these urethane groups, and one or more acrylate or methacrylate groups. Each urethane (meth)acrylate is generally obtained by reacting an isocyanate compound having one or more isocyanate (-NCO) groups with an acrylic acid ester or methacrylic acid ester having one or more hydroxy (-OH) groups. For example, one useful urethane (meth)acrylate is obtained by reacting hexamethylene diisocyanate with dipentaerythritol pentaacrylate. Other useful urethanes include those obtained by reacting DESMODUR® N100 aliphatic polyisocyanate resin (Bayer Corp., Milford, Connecticut), which is based on hexamethylene diisocyanate, with hydroxyethyl acrylate, pentaerythritol triacrylate, and dipentaerythritol pentaacrylate. For example, at least one of the one or more urethane (meth)acrylates contains at least five acrylate groups or methacrylate groups, or even more than ten acrylate groups or methacrylate groups.

[0040] In some embodiments, one or more urethane (meth)acrylates have the following structure (III): L'-[NH-C(=O)-O-X'] p (III) [In the formula, L' represents a p-valent linking group, where p is an integer of 2 or 3, and X' is represented by the following structure (IV), -A'(R') n’ (IV) In the formula, A' represents an n'+1 valent organic group, and R' represents a hydroxyl group, an acrylic acid ester group [CH2=CHC(=O)O-], or a methacrylic acid ester group [(CH2=C(CH3)C(=O)O-] independently, where n' is an integer between 1 and 6, provided that not all R' groups are hydroxyl groups].

[0041] L' can be a linear, branched, or cyclic organic group, such as a linear, branched, or cyclic hydrocarbon group, such as an aliphatic hydrocarbon group. Useful examples of the L' group include the hexamethylene[-(CH2)6-] group, the -CH2CH(CH3)CH2C(CH3)2CH2CH2- group, and the following groups: [ka]

[0042] The hexamethylene group is particularly useful for L'.

[0043] In structure (IV), a particularly useful example of the A' group is in the following structure (V): [ka] (V) (In the formula, * represents the connection point with the R' group.) This is represented by the formula. Other useful examples of the A' group include -CH2-CH2*, -CH2-CH2-CH2*, -CH2-CH(CH3)*, -CH2-CH(*)-CH2*, -CH(CH2*)2, and -C(CH2CH3)(CH2*)2, where * again represents the connection point with the R' group.

[0044] Useful urethane (meth)acrylates typically have a weight-average molecular weight of at least 500, more typically at least 1,000 to 10,000 or less, and more typically 5,000 or less. The weight-average molecular weight can be determined using gel permeation chromatography (GPC) calibrated with a set of polystyrene standards, which is a technique well known to those skilled in the art.

[0045] Useful urethane (meth)acrylates can be obtained from various commercial sources known to those skilled in the art.

[0046] a) At least one other essential compound in two or more free radical polymerizable components should be a polyester (meth)acrylate. That is, this compound may be a polyester acrylate or a polyester methacrylate compound, but both types of compounds may be present. Such a polyester (meth)acrylate does not contain urethane bonds and contains one or more acrylate groups or methacrylate groups and two or more ester groups [-OC(=O)*] linked to each other via single bonds or carbon-carbon linkage groups (carbon chains) at connection points*. Typically, each polyester (meth)acrylate may have 1 to 15 or 4 to 15 acrylate or methacrylate groups in each molecule.

[0047] In some embodiments, each polyester (meth)acrylate has the following structure (I): X-OC(=O)-LC(=O)-OY (I) This can be represented as follows, where L represents a single bond or a carbon chain having at least two bonded carbon atoms and up to 10 bonded carbon atoms. For example, the L bond in structure (I) may be a linear, branched, or cyclic saturated hydrocarbon chain containing 2 to 10 carbon atoms, or a linear, branched, or cyclic carbon chain containing 2 to 10 carbon atoms and at least one carbon-carbon unsaturated group. Such groups may be aromatic or non-aromatic in nature.

[0048] For example, L consists of a single bond, a *CH2-CH2* group, a *CH=CH* group, and the following groups Ia and Ib: [ka] (Ia), and [ka] (Ib) (In the formula, * represents a connection point with the rest of structure (I)) One of the following may be selected.

[0049] Furthermore, X and Y in structure (I) may be the same or different, and independently represent a hydrogen atom or an organic group represented in structure (II) below, except that both X and Y cannot be hydrogen atoms: -A(R) n (II) (In the formula, A represents an n+1 valent organic group). Useful examples of the A' group in structure (IV) above can also represent useful examples of A in structure (II). Among these, -C(CH2CH3)(CH2*)2 is a particularly useful example of A.

[0050] R represents a hydroxyl group, an acrylic acid ester group [CH2=CHC(=O)O-], or a methacrylic acid ester group [CH2=C(CH3)C(=O)O-], and n is an integer between 1 and 12 (more typically between 1 and 5), however, not all R groups are hydroxyl groups.

[0051] Useful polyester (meth)acrylates typically have a weight-average molecular weight of at least 500, more typically at least 1,000 to 10,000 or less, and more typically 5,000 or less. The weight-average molecular weight can be determined using gel permeation chromatography (GPC) calibrated with a set of polystyrene standards, which is a technique well known to those skilled in the art.

[0052] The total amount of urethane (meth)acrylate and polyester (meth)acrylate in the negative infrared-sensitive image recording layer is a) at least 75% by weight, at least 80% by weight, or even more than 90% by weight, and 90% or less by weight or 100% or less, relative to the total weight of all two or more free radical polymerizable components. If the total amount of urethane (meth)acrylate and polyester (meth)acrylate is less than 75% by weight, the imaged and developed negative plate is likely to exhibit insufficient on-press print durability (LOR as defined above) after an unexposed and undeveloped negative plate has been exposed to ambient ozone.

[0053] Furthermore, a) two or more free radical polymerizable components are present in an amount of at least 20% by weight or at least 30% by weight, and 70% by weight or less or 80% by weight or less, relative to the total solid content of the negative infrared-sensitive image recording layer of the original plate of the present invention.

[0054] a) It is also extremely important that, in two or more free radical polymerizable components, the weight ratio of one or more urethane (meth)acrylates to one or more polyester (meth)acrylates is 90:10 to 35:65 or less, or 75:25 to 50:50 or less.

[0055] It is not essential, but possible, to include one or more additional free radical polymerizable components among the two or more free radical polymerizable components used in each negative infrared-sensitive image recording layer, other than urethane (meth)acrylate and polyester (meth)acrylate (both described above). Such additional compounds do not contain urethane bonds or structures having at least two ester groups linked to each other by single bonds or carbon-carbon chains. If present, such one or more additional free radical polymerizable components may all be present in an amount of at least 0.5% by weight and less than 25% by weight, less than 20% by weight, or even less than 15% by weight, relative to the total weight of the two or more free radical polymerizable components.

[0056] For example, each of the one or more further free radical polymerizable components may contain a glycol ether bond [-OMO-], where M represents -CH2-CH2- or CH2-CH(CH3)-.

[0057] Representative examples of one or more additional free radical polymerizable components include, but are not limited to, NK Ester A-DPH (dipentaerythritol hexaacrylate) available from Kowa American, Sartomer SR399 (dipentaerythritol pentaacrylate), Sartomer SR355 (ditrimethylolpropane tetraacrylate), Sartomer SR295 (pentaerythritol tetraacrylate), and Sartomer SR415 [ethoxylated (20) trimethylolpropane triacrylate] available from Sartomer Company, Inc.

[0058] a) One or more of the two or more free radical polymerizable components may have a sufficiently large molecular weight or sufficient polymerizable groups to provide a crosslinkable polymer matrix that functions as a "polymer binder" for other components in the negative infrared-sensitive image recording layer. In such embodiments, a separate non-free radical polymerizable polymer binder (described below) is not required.

[0059] Furthermore, the present invention utilizes b) initiator compositions in each negative-type infrared-sensitive image recording layer. Such initiator compositions may contain one or more compounds that can generate free radicals when the chemical reaction system for image formation in the negative-type infrared-sensitive image recording layer is appropriately exposed. Examples of such compounds include, but are not limited to, organohalogen compounds, such as trihaloallyl compounds; trihalomethylarylsulfones; bis(trihalomethyl)triazines; and onium salts, such as iodonium salts, sulfonium salts, diazonium salts, phosphonium salts, and ammonium salts, many of which are known in the art. For example, representative compounds other than onium salts are described in sections

[0087] to

[0102] of U.S. Patent Application Publication No. 2005 / 0170282 (Inno et al., U.S. Patent Application Publication '282) and U.S. Patent No. 6,309,792 (Hauck et al.), as well as in Japanese Patent Publication No. 2002 / 107916 and International Publication No. 2019 / 179995.

[0060] Useful onium salts are described, for example, in paragraphs

[0103] to

[0109] of the aforementioned U.S. Patent Application Publication '282. For example, a useful onium salt contains at least one onium cation and a suitable anion in the molecule. Examples of onium salts include triphenylsulfonium, diphenyliodonium, diphenyldiazonium, compounds obtained by introducing one or more substituents to the benzene ring of these compounds, and their derivatives. Suitable substituents include, but are not limited to, alkyl, alkoxy, alkoxycarbonyl, acyl, acyloxy, chloro, bromo, fluoro, and nitro groups.

[0061] Examples of anions in onium salts include halogen anions and ClO4. - PF6 - BF4 - SbF6 - CH3SO3 - CF3SO3 - , C6H5SO3 - CH3C6H4SO3- HOC6H4SO3 - ClC6H4SO3 - Examples include, but are not limited to, boron anions (e.g., tetraarylborate anions as described in U.S. Patent No. 7,524,614 (Tao et al.)).

[0062] Typical useful iodonium salts are described in columns 6-7 of U.S. Patent No. 7,524,614 (above), where the iodonium cation may include the various monovalent substituents "X" and "Y" listed, or carbocyclic or heterocyclic rings fused to a phenyl group, respectively.

[0063] Useful onium salts can be polyvalent onium salts that have at least two onium ions covalently bonded together in the molecule. Among polyvalent onium salts, those having at least two onium ions in the molecule are useful, and those having a sulfonium cation or iodonium cation in the molecule are particularly useful.

[0064] Furthermore, onium salts described in paragraphs

[0033] to

[0038] of Japanese Patent Publication No. 2002-082429 [or U.S. Patent Application Publication No. 2002-0051934 (Nakamura et al.)] and iodonium borate complexes described in U.S. Patent No. 7,524,614 (above) may also be used. Typical iodonium borate salts are listed, for example, in column 8 of U.S. Patent No. 7,524,614 (above). Such iodonium borate salts have the following structure: B + (R 1 )(R 2 )(R 3 )(R 4 ) - It may contain a borate anion represented by the formula, where R 1 , R 2 , R 3 , and R 4Each independently represents a substituted or unsubstituted alkyl, aryl, alkenyl, alkynyl, cycloalkyl, or heterocyclic group bonded to a boron atom, or R 1 , R 2 , R 3 , and R 4 Two or more of these atoms can bond together to form a heterocycle with a boron atom, each of which may have up to seven carbon, nitrogen, oxygen, or sulfur atoms. For example, tetraarylborate anions such as tetraphenylborate and triarylalkylborates, such as triphenylalkylborate compounds, are useful.

[0065] In some embodiments, a combination of onium salts, for example, a combination of compounds described in U.S. Patent Application Publication No. 2017 / 0217149 (Hayashi et al.), may be used as part of the initiator composition.

[0066] b) Since initiator compositions may have multiple components, useful amounts or dry coating amounts of various components of b) initiator compositions in each negative infrared-sensitive image recording layer will be readily apparent to those skilled in the art, based on the knowledge of those skilled in the art and the representative teachings provided herein, including the examples shown below. b) Useful materials in initiator compositions capable of generating free radicals are readily available from commercial sources worldwide or can be readily prepared using known starting materials and synthesis methods performed by skilled synthetic chemists.

[0067] Furthermore, each of the one or more negative infrared-sensitive image recording layers contains one or more infrared-absorbing cyanine dyes to provide a desired infrared sensitivity, or to convert radiation into heat, or both. Suitable cyanine dyes for this purpose are described, for example, in U.S. Patent No. 5,208,135 (Patel et al.), No. 6,153,356 (Urano et al.), No. 6,309,792 (Hauck et al.), No. 6,569,603 (Furukawa), No. 6,797,449 (Nakamura et al.), No. 7,018,775 (Tao), No. 7,368,215 (Munnelly et al.), No. 8,632,941 (Balbinot et al.), and U.S. Patent Application Publication No. 2007 / 056457 (Iwai et al.). A suitable cyanine dye comprises a suitable cationic cyanine chromophore and a suitable anion, such as a tetraarylborate anion, including a tetraphenylborate anion. An example of such a dye is described in U.S. Patent Application Publication 2011 / 003123 (Simpson et al.).

[0068] In carrying out the present invention, c) equally useful as infrared-absorbing cyanine dyes are at least

[0088] to

[0097] of U.S. Patent Application Publication No. 2022 / 0324220 (A1) (Simpson et al.), at least

[0091] to

[0100] of U.S. Patent Application Publication No. 2022 / 0317569 (A1) (Simpson et al.), and cyanine compounds described as “discoloration compounds” in concurrently pending U.S. Patent Application Publication No. 2023 / 0314935 (Simpson et al.) and U.S. Patent Application Publication No. 2024 / 0069439 (Simpson et al.) by the same applicant. These discoloration compounds can be used alone or in combination with those described in the preceding paragraph, such as infrared-absorbing cyanine dyes that do not show significant discoloration, for example, the cyanine dye described in U.S. Patent No. 6,797,449 (Nakamura et al., above).

[0069] c) The total amount of one or more infrared-absorbing cyanine dyes is at least 0.5% by weight or at least 1% by weight relative to the total solid content of at least one or more negative-type infrared-sensitive image recording layers, and is 15% by weight or less or 30% by weight or less. The amount of c) one or more infrared-absorbing cyanine dyes described is what may be present in one or more negative-type infrared-sensitive image recording layers, and the amount described represents the total amount in the original plate.

[0070] In some embodiments, and preferably, the negative infrared-sensitive image recording layer further comprises one or more non-free-radical polymerizable polymer materials (or polymer binders), each of which has no functional groups that would enable the polymer material to be free-radical polymerizable, if present. Thus, such non-free-radical polymerizable polymer materials are different from a) the two or more free-radical polymerizable components described above, and different from all of b) the initiator composition and c) the one or more infrared-absorbing cyanine dyes described above.

[0071] Useful non-free radical polymerizable polymer binders generally have a weight-average molecular weight (M) determined by gel permeation chromatography (polystyrene standard). w ) is at least 2,000 or at least 20,000, and is 300,000 or 500,000 or less.

[0072] Such non-free radical polymerizable polymer binders can be selected from polymer materials known in the art, including polymers containing repeating units having side chains containing polyalkylene oxide segments, such as those described in U.S. Patent No. 6,899,994 (Huang et al.). Other useful polymer binders include two or more repeating units having different side chains containing polyalkylene oxide segments, such as those described in International Publication No. 2015-156065 (Kamiya et al.). Some of these polymer binders may further include repeating units having pendant cyano groups, such as those described in U.S. Patent No. 7,261,998 (Hayashi et al.).

[0073] Such non-free radical polymerizable polymer binders may also have a backbone comprising multiple (at least two) urethane moieties and a pendant group comprising a polyalkylene oxide segment.

[0074] Some particularly useful non-free radical polymerizable polymer binders exist in particulate form, i.e., discrete particles (non-aggregated particles), which may have an average particle size of at least 10 nm to 1500 nm, or typically at least 80 nm to 600 nm, and are generally uniformly distributed in the negative infrared-sensitive image recording layer. Some of these polymer binders may exist in particulate form and may have an average particle size of at least 50 nm to 400 nm. The average particle size can be determined using various known methods and particle measuring devices, for example, by measuring particles in electron scanning microscope images and averaging a set number of measurements.

[0075] One or more non-free radical polymerizable polymer binders may be present in amounts of at least 10% by weight or at least 20% by weight, and 50% by weight or less or 70% by weight or less, relative to the total solid content of each negative infrared-sensitive image recording layer.

[0076] The negative infrared-sensitive image recording layer may optionally contain crosslinked polymer particles, such as those described in, for example, U.S. Patent No. 9,366,962 (Hayakawa et al.), U.S. Patent No. 8,383,319 (Huang et al.), and U.S. Patent No. 8,105,751 (Endo et al.), having an average particle size of at least 2 μm or at least 4 μm to 20 μm.

[0077] In some embodiments, the negative infrared-sensitive image recording layer may, but preferably, further comprise one or more acid-sensitive dye precursors. Useful acid-sensitive dye precursors are described in the sections 31, 32, and 33 of U.S. Patent No. 11,294,279 (B2) (Ishiji et al.) regarding acid-sensitive dyes, as well as in U.S. Patent Publication No. 2022 / 0111629 (Enomoto et al.), No. 2021 / 0078350 (Viehmann et al.), and No. 2023 / 0091079 (Hansmann et al.).

[0078] The negative infrared-sensitive image recording layer may also contain, in conventional amounts, various other additives, including but not limited to, dispersants, humectants, biocides, plasticizers, surfactants for coating or other properties, viscosity modifiers, pH adjusters, desiccants, defoamers, developer aids, rheology modifiers, or combinations thereof, or any other additives commonly used in lithographic coating technology. The negative infrared-sensitive image recording layer may also contain phosphoric (meth)acrylates with a molecular weight generally exceeding 250, as described in U.S. Patent No. 7,429,445 (Munnelly et al.). Furthermore, the negative infrared-sensitive image recording layer may optionally include one or more suitable chain transfer agents, antioxidants, or stabilizers (inhibitors) to prevent or moderate undesirable radical reactions, as described, for example, in sections

[0144] to

[0149] of European Patent No. 2,735,903 (B1) (Werner et al.) and columns 7 to 9 of U.S. Patent No. 7,189,494 (Munnelly et al.).

[0079] Protective layer: The negative infrared-sensitive image recording layer may be the outermost layer, but some of the master plates according to the present invention may be designed with a protective layer placed on top of the outermost negative infrared-sensitive image recording layer. The protective layer is typically hydrophilic, as is known in the art, but may also be hydrophobic or contain hydrophobic components as described in PCT Patent Application Publication 2019 / 243036 (A1). However, for the purpose of protecting the negative infrared-sensitive image recording layer according to the present invention, the use of a) a) unique combination of two or more free radical polymerizable components is advantageous over conventional oxygen-barrier protective layers. This is because the latter may have undesirable effects on negative lithographic master plates, particularly those designed for on-press development, such as slow ink evacuation, dampening water contamination, and reduced image durability due to uncontrolled mixing between the protective layer and the negative infrared-sensitive image recording layer.

[0080] Manufacturing of negative-type lithographic printing plates. The negative lithographic printing plates according to the present invention may be provided in the following forms: One or more negative infrared-sensitive image recording layer formulations, each comprising the essential components a), b), and c) described above and the other additives described above, dissolved or dispersed in a suitable solvent, can be applied to the hydrophilic surface of a suitable aluminum-containing substrate as described above using any suitable apparatus and procedure, e.g., spin coating, knife coating, gravure coating, die coating, slot coating, bar coating, wire rod coating, roller coating, or extrusion hopper coating. Such formulations can also be applied by spraying onto a suitable aluminum-containing substrate. Typically, once the negative infrared-sensitive image recording layer formulation is applied to a suitable wet coverage amount, the formulation is dried in a suitable manner known in the art to give a desired dry coverage amount (solid coverage amount) as described below.

[0081] A solvent suitable for producing the master plate according to the present invention may consist of water and / or one or more organic solvents. Examples of useful organic solvents include methyl ethyl ketone (2-butanone), methanol, ethanol, 1-methoxy-2-propanol, 2-methoxypropanol, isopropyl alcohol, acetone, γ-butyrolactone, n-propanol, tetrahydrofuran, and others readily known in the art.

[0082] After proper drying, the dry coating weight (or total solids content) of each of the at least one negative-type infrared-sensitive image recording layers on the aluminum-containing substrate is generally at least 0.1 g / m². 2 Or at least 0.4 g / m 2 And 2g / m 2 or less, or 4g / m² 2 The following applies, but other dry coating amounts can be used if desired.

[0083] Under actual manufacturing conditions, the result of these coating operations is a continuous web (or roll) of negative infrared-sensitive lithographic printing plate material having one or more negative infrared-sensitive image recording layers and optionally a protective layer, present on a suitable aluminum-containing substrate. Such a continuous web of this structure can be elongated or cut into plates of a suitable size for use.

[0084] Image formation (exposure) conditions During use, the negative infrared-sensitive lithographic printing plate of the present invention can be exposed to a suitable infrared source depending on one or more infrared-absorbing cyanine dyes present in one or more negative infrared-sensitive image recording layers. In some embodiments, the negative infrared-sensitive lithographic printing plate can be imaged with one or more lasers emitting a considerable amount of infrared radiation in the range of at least 750 nm to 1400 nm or at least 800 nm to 1250 nm to create exposed and unexposed regions in one or more negative infrared-sensitive image recording layers. Such infrared-emitting lasers can be used for such image formation in response to digital information supplied by a computing device or other digital information source. Laser imaging can be digitally controlled in a suitable manner known in the art.

[0085] Therefore, imaging can be carried out using imaging infrared or exposure infrared from an infrared generating laser or an array of such lasers. Imaging can also be carried out using imaging radiation of multiple infrared (or near-IR) wavelengths simultaneously, if desired. The one or more lasers used to expose the master plate are usually one or more diode lasers due to the reliability and low maintenance of diode laser systems, but other lasers, such as gas or solid-state lasers, may also be used. Combinations of power, intensity, and exposure time for infrared imaging will be readily apparent to those skilled in the art.

[0086] Infrared imaging apparatuses can be configured as flatbed recorders or drum recorders in which infrared-sensitive lithographic printing plates are mounted on the inner or outer cylindrical surface of a drum. Examples of useful imaging apparatuses include the KODAK® Trendsetter platesetter (Eastman Kodak Company) and the NEC AMZISetter X series (NEC Corporation, Japan), which include laser diodes emitting radiation at a wavelength of approximately 830 nm. Other suitable imaging apparatuses include the Screen PlateRite 4300 series or 8600 series platesetters (available from Screen USA, Chicago, Illinois), or the Panasonic Corporation (Japan) thermal CTP platesetters operating at a wavelength of 810 nm.

[0087] When an infrared image-forming source is used, the image-forming energy intensity is at least 30 mJ / cm², depending on the sensitivity of one or more infrared-sensitive image recording layers. 2 ~500mJ / cm 2 The following are typically at least 50 mJ / cm² 2 ~300 mJ / cm 2 The following are possible:

[0088] Processing (developing) and printing As described above, after image-like exposure, the exposed infrared-sensitive lithographic printing plate, having exposed and unexposed regions in each infrared-sensitive image recording layer, can be processed either off-machine or on-machine to remove the unexposed regions (and, if present, the protective layer on the unexposed regions) from the exposed negative-type infrared-sensitive lithographic printing plate. After this processing and during lithographic printing, the exposed hydrophilic aluminum-containing substrate surface repels ink, while the remaining exposed regions accept lithographic printing ink. On-machine processing is particularly preferred and is described below.

[0089] Onboard developing and printing: Some negative lithographic printing plates of the present invention are press-developable using lithographic ink, dampening solution, or a combination of lithographic ink and dampening solution. In such embodiments, the image-formed (exposed) infrared-sensitive lithographic printing plate according to the present invention is mounted on a printing press and the printing operation is started. Unexposed areas in the infrared-sensitive image recording layer are removed by appropriate dampening solution, lithographic ink, or a combination thereof once the first printed print is produced.

[0090] In a typical sheet-fed printing press startup, the dampening roller is engaged first, supplying dampening water to the mounted image-formed plate to swell the exposed infrared-sensitive image recording layer, at least in the unexposed areas. After several rotations, the inking roller is engaged, supplying one or more lithographic inks to the entire printing surface of the lithographic plate. Typically, within 5 to 20 rotations after the inking roller is engaged, the printing paper is fed, and lithographic printing begins. Initially, the pressed paper may have some ink or infrared-sensitive image recording layer from the lithographic plate adhering to the unexposed areas. The removal of one or more infrared-sensitive image recording layers from the unexposed areas may proceed from the engagement of the dampening roller until the unexposed areas of the lithographic plate no longer transfer ink to the printing paper.

[0091] While the present invention provides at least the following embodiments and combinations thereof, other combinations of features are also considered to be within the scope of the invention, as those skilled in the art will understand from the teachings of this disclosure.

[0092] 1. A negative-type lithographic printing plate master comprising an aluminum-containing substrate and a negative-type infrared-sensitive image recording layer disposed on the aluminum-containing substrate, The negative infrared-sensitive image recording layer is a) Two or more free radical polymerizable components, b) an initiator composition capable of generating free radicals, and c) Contains one or more infrared absorbing cyanine dyes, a) comprising one or more urethane (meth)acrylates and one or more polyester (meth)acrylates, wherein two or more free radical polymerizable components together constitute at least 75% to 100% by weight of all free radical polymerizable components. The weight ratio of one or more urethane (meth)acrylates to one or more polyester (meth)acrylates is 90:10 to 35:65 or less. Each of the one or more urethane (meth)acrylates comprises one or more urethane bonds and at least four acrylic acid ester groups or methacrylic acid ester groups. Each of the one or more polyester (meth)acrylates does not contain a urethane bond and has the following structure (I): X-OC(=O)-LC(=O)-OY (I) [In the formula, L represents a single bond or carbon chain, and X and Y independently represent a hydrogen atom or an organic group represented by the following structure (II), however, X and Y cannot both be hydrogen atoms.] -A(R) n (II) In the formula, A represents an n+1 valent organic group, R represents a hydroxyl group, an acrylic acid ester group (CH2=CHC(=O)O-), or a methacrylic acid ester group (CH2=C(CH3)C(=O)O-), and n is an integer between 1 and 12, provided that not all R groups are hydroxyl groups. Negative type lithographic printing plate original.

[0093] 2.1 or more urethane (meth)acrylates and 1 or more polyester (meth)acrylates together constitute at least 80% by weight of all of the 2 or more free radical polymerizable components, as described in Embodiment 1.

[0094] 3. A negative-type lithographic printing plate according to Embodiment 1 or 2, wherein the outermost layer is a negative-type infrared-sensitive image recording layer.

[0095] 4. A negative-type lithographic printing plate according to any one of embodiments 1 to 3, which can be developed on-press using lithographic ink, dampening solution, or a combination of lithographic ink and dampening solution.

[0096] 5. The L bond in structure (I) is a single bond, a *CH2-CH2* group, a *CH=CH* group, and the following groups Ia and Ib: [ka] (Ia), and [ka] (Ib) (In the formula, * represents a connection point with the rest of structure (I)) A negative type lithographic printing plate master according to Embodiment 3, selected from any of the following.

[0097] 6. A negative type lithographic printing plate according to any one of Embodiments 1 to 5, wherein the negative type infrared-sensitive image recording layer further comprises a particulate non-free radical polymerizable polymer binder.

[0098] 7.a) A negative type lithographic printing plate according to any one of Embodiments 1 to 6, wherein two or more free radical polymerizable components are present in an amount of at least 20% to 80% by weight relative to the total solid content of the negative type infrared-sensitive image recording layer.

[0099] 8. A negative type lithographic printing plate according to any one of Embodiments 1 to 7, wherein the aluminum-containing substrate comprises two or more aluminum oxide layers and a hydrophilic polymer coating disposed on the outermost aluminum oxide layer.

[0100] 9.1 A negative type lithographic printing plate according to any one of Embodiments 1 to 8, wherein at least one of the 1 or more urethane (meth)acrylates contains at least five acrylate groups or methacrylate groups.

[0101] 10. A negative type lithographic printing plate according to any one of Embodiments 1 to 9, wherein at least one of 10 or more urethane (meth)acrylates contains at least 10 acrylate groups or methacrylate groups.

[0102] 11.a) A negative type lithographic printing plate according to any one of Embodiments 1 to 10, wherein two or more free radical polymerizable components further comprise one or more further free radical polymerizable components, none of which contain urethane bonds, none of which contain structures having at least two ester groups bonded to each other by bonds or carbon-carbon chains, but each of the one or more further free radical polymerizable components comprises one or more (meth)acrylic acid ester groups, and the one or more further free radical polymerizable components are present in a total amount of less than 25% by weight relative to the total weight of the two or more free radical polymerizable components.

[0103] 12.1 A negative type lithographic printing plate according to Embodiment 11, wherein each of the 1 or more further free radical polymerizable components comprises a glycol ether bond [-OMO-] (wherein M represents -CH2-CH2- or CH2-CH(CH3)-).

[0104] 13.1 or more types of urethane (meth)acrylates have the following structure (III): L'-[NH-C(=O)-O-X'] p (III) [In the formula, L' represents a p-valent linking group, where p is an integer of 2 or 3, and X' is represented by the following structure (IV), -A'(R') n’ (IV) In the formula, A' represents an n'+1 valent organic group, and R' represents a hydroxyl group, an acrylic acid ester group [CH2=CHC(=O)O-], or a methacrylic acid ester group [(CH2=C(CH3)C(=O)O-] independently, where n' is an integer between 1 and 6, provided that not all R' groups are hydroxyl groups]. A negative-type lithographic printing plate master according to any one of Embodiments 1 to 12.

[0105] 14. A negative type lithographic printing plate according to Embodiment 13, wherein L' is a hydrocarbon group.

[0106] 15. A negative type lithographic printing plate according to Embodiment 13 or 14, wherein L' is an aliphatic hydrocarbon group.

[0107] 16. A negative type lithographic printing plate according to any one of embodiments 13 to 15, wherein L' is a hexamethylene [-(CH2)6-] group.

[0108] 17. A' has the following structure (V): [ka] (V) (In the formula, * represents the connection point with the R' group.) A negative type lithographic printing plate according to any one of embodiments 13 to 16, represented by [the formula shown].

[0109] 18. A negative-type lithographic printing plate master comprising an aluminum-containing substrate containing two or more aluminum oxide layers, and a negative-type infrared-sensitive image recording layer disposed as the outermost layer on the aluminum-containing substrate, The negative infrared-sensitive image recording layer is a) Two or more free radical polymerizable components, b) An initiator composition that can generate free radicals and comprises an iodonium cation and a tetraarylborate anion, and c) Contains one or more infrared absorbing cyanine dyes, a) comprising one or more urethane (meth)acrylates and one or more polyester (meth)acrylates, wherein two or more free radical polymerizable components together constitute at least 80% to 100% by weight of all free radical polymerizable components. The weight ratio of one or more types of urethane (meth)acrylate to one or more types of polyester (meth)acrylate is 75:25 to 50:50 or less. Each of the one or more urethane (meth)acrylates contains one or more urethane bonds and at least four acrylic acid ester groups or methacrylic acid ester groups, and has the following structure (III): L'-[NH-C(=O)-O-X'] p (III) [In the formula, L' represents a p-valent linking group, where p is an integer of 2 or 3, and X' is represented by the following structure (IV), -A'(R') n’ (IV) In the formula, A' represents an n'+1 valent organic group, R' represents a hydroxyl group, an acrylic acid ester group [CH2=CHC(=O)O-], or a methacrylic acid ester group [(CH2=C(CH3)C(=O)O-] independently, and n' is an integer between 1 and 6, provided that not all R' groups are hydroxyl groups]. Each of the one or more polyester (meth)acrylates does not contain a urethane bond and has the following structure (I): X-OC(=O)-LC(=O)-OY (I) [In the formula, L represents a single bond, or a *CH2-CH2* group, a *CH=CH* group, and the groups Ia and Ib shown below: [ka] (Ia), and [ka] (Ib) (In the formula, * represents a connection point with the rest of structure (I)), and X and Y independently represent a hydrogen atom or an organic group represented by the following structure (II), however, X and Y cannot both be hydrogen atoms. -A(R) n (II) In the formula, A represents an n+1 valent organic group, R represents a hydroxyl group, an acrylic acid ester group (CH2=CHC(=O)O-), or a methacrylic acid ester group (CH2=C(CH3)C(=O)O-), and n is an integer between 1 and 12, provided that not all R groups are hydroxyl groups. Negative type lithographic printing plate original.

[0110] 19. A method for providing a lithographic printing plate, A) A step of exposing a negative type lithographic printing plate master according to any one of Embodiments 1 to 18 to an image-like exposure with image-forming infrared light to provide exposed regions and unexposed regions in a negative type infrared-sensitive image recording layer, and B) A process of removing unexposed areas in the negative-type infrared-sensitive image recording layer from the aluminum-containing substrate. Methods that include...

[0111] 20. The method according to Embodiment 19, comprising the step of removing unexposed areas in a negative infrared-sensitive image recording layer from an aluminum-containing substrate on machine using lithographic ink, dampening solution, or a combination of lithographic ink and dampening solution.

[0112] The following embodiments are provided to further illustrate the implementation of the invention and are not intended to limit it in any way. Unless otherwise indicated, the materials used in the embodiments were obtained from various commercial sources as shown, but other commercial sources may also be available.

[0113] Examples 1-12 and Comparative Examples 1-14 of the present invention Manufacturing of aluminum-containing substrates: An aluminum-containing substrate was manufactured for use in both the present example and comparative example lithographic printing plates, according to the teachings in Example 1 of the U.S. Patent Application Publication No. 2019 / 0016110 (Merka et al., hereinafter referred to as U.S. Patent No. 110).

[0114] In short, aluminum-containing substrates were manufactured using 0.28 mm thick Hydro 1052 aluminum alloy strips or webs (Norsk Hydro ASA, available from Norway) as aluminum-containing "plates" or supports. Both pre-etching and post-etching processes were carried out in alkaline solutions under known conditions. Roughening (or granulation) was performed electrochemically in a hydrochloric acid solution at approximately 23°C to obtain an arithmetic mean roughness (Ra) of 0.5 μm on the surface of the aluminum-containing supports. These processing steps were carried out in a continuous process on a typical manufacturing line used for the production of lithographic printing plates. The resulting granulated and etched aluminum-containing supports were then rinsed with water, dried, and cut into individual granulated and etched aluminum-containing sheets. Each individual sheet was then anodized twice. Here, each anodizing process bath contained approximately 100 liters of anodizing solution. The first and second anodizing conditions are shown in Table I of U.S. Patent No. 110. A first anodizing process for forming the outer aluminum oxide layer was carried out using phosphoric acid as the electrolyte, and a second anodizing process for forming the inner aluminum oxide layer was carried out using sulfuric acid as the electrolyte. Further details regarding other features of the aluminum-containing substrate thus produced are described in Example 1 of Invention in Table II of U.S. Patent No. 110.

[0115] A hydrophilic layer was placed on the manufactured aluminum-containing substrate as follows.

[0116] Preparation of hydrophilic layer formulations: 3500 g of ethanol was placed in a 10-liter reaction vessel equipped with a condenser, and then heated to 70°C to prepare polymer 1, a copolymer derived from vinylphosphonic acid and acrylamide (molar ratio 1:9). Next, 231.1 g of vinylphosphonic acid monomer and 1368.9 g of acrylamide monomer were mixed with 1000 g of ethanol, and 52 g of AIBN polymerization initiator was dissolved in the monomer mixture. The resulting polymerization mixture was added dropwise to the reaction vessel at 70°C for 4 hours. After this addition, the polymerization mixture was maintained at 70°C for 2 hours and then cooled to room temperature. The precipitated white powder copolymer was isolated by filtration and washed with 1 liter of ethanol to obtain a yield of 1550 g.

[0117] The hydrophilic layer compositions SL-1 and SL-2, which are placed on a treated and anodized aluminum-containing support, were prepared from the components shown in Table I below.

[0118] [Table 1]

[0119] ACUMER® 1000 Polymer is an aqueous solution (50% by weight) of poly(acrylic acid) obtained from The Dow Chemical Company.

[0120] TAKESURF(registered trademark) D-410-GL is a leveling agent obtained from TAKEMOTO OIL & FAT CO.,LTD.

[0121] Each of the hydrophilic layer formulations listed in Table I should be 20 g / m² 2 The aluminum-containing support sample was coated using a wound coating bar to achieve the wet coating weight, and then dried at 80°C for 2 minutes.

[0122] Preparation of negative-type infrared-sensitive image recording layer formulations: These formulations (MC-1 to MC-26) having the components shown in Table II below were prepared. Each of these formulations has a total solids content of 5% by weight when dissolved or dispersed in a coating solvent mixture containing 35% by weight n-propanol, 20% by weight 2-methoxypropanol, 35% by weight 2-butanone, and 10% by weight water. The raw materials listed in Table III below can be obtained from one or more commercial sources of chemicals or can be prepared by those skilled in the art using known synthesis methods.

[0123] [Table 2A]

[0124] [Table 2B]

[0125] [Table 2C]

[0126] [Table 2D]

[0127] [Table 2E]

[0128] [Table 2F]

[0129] In Table II, "AA" represents the total weight of all two or more free radical polymerizable components, "UA" represents the total weight of one or more urethane (meth)acrylates, and "PEA" represents the total weight of one or more polyester (meth)acrylates. Therefore, "(UA+PEA) / AA" represents the ratio of the total weight of one or more urethane (meth)acrylates and one or more polyester (meth)acrylates to all of the two or more free radical polymerizable components, and according to the present invention, it should be at least 75% by weight. "PU / (UA+PEA)" represents the ratio of the total weight of one or more urethane (meth)acrylates to the total weight of the combination of one or more urethane (meth)acrylates and one or more polyester (meth)acrylates, and according to the present invention, it should be in the range of 35% to 90% by weight or less.

[0130] [Table 3]

[0131] Each negative-type infrared-sensitive image recording layer formulation was coated onto a substrate coated with a sublayer, then coated onto the hydrophilic layer of a suitable aluminum-containing substrate using a wound coating bar, dried at 80°C for 2 minutes, and the resulting layer was 1 g / m². 2 A negative-type infrared-sensitive image recording layer having a dry coating amount was obtained.

[0132] The obtained negative-type lithographic printing plates having an outermost negative-type infrared-sensitive image recording layer (both examples and comparative examples of the present invention) are specified in Table IV below.

[0133] [Table 4]

[0134] Evaluation of negative-type lithographic printing plates: The original plates of the present invention example and comparative example obtained as described above were each exposed to a solid area at an exposure energy of 150 mJ / cm using a KODAK Magnus 800 imagesetter.2 Images were formed using the following method. The original plates of the present invention example and comparative example were also evaluated for several characteristics described below.

[0135] On-press developability (DOP): Each negative-type lithographic printing plate was imaged as described above and mounted on a Roland R-201 printing press for on-press 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 Topcoat Matte N grade paper (Oji paper) as printing paper, and lithographic printing ink (Fusion G Magenta N, sold by DIC Graphics), and printing was performed at a printing speed of 9,000 sheets / hour. On-press developability (DOP) was evaluated by the number of printed sheets at which no further ink transfer was observed in the non-image-forming area.

[0136] Each negative-type lithographic printing plate master was stored in the following two ways, and then the DOP was evaluated. First, each sample of the negative-type lithographic printing plate master of the present invention example or comparative example was wrapped in light-shielding paper immediately after manufacturing and stored at 25°C for 7 days (this storage condition is referred to as "NK7"). Second, each sample of the negative-type lithographic printing plate master of the present invention example and comparative example was stored in a commercially available humidity chamber ETAC FX-430 at 50°C for 7 days (this storage condition is referred to as "DT7").

[0137] For all evaluations, a DOP of less than 50 is highly desirable, and a DOP exceeding 100 is unacceptable under proven press conditions consistent with commercial lithographic printing conditions. The smaller the difference ("gap") in DOP between NK7 and DT7, the better the stability of image formation in the original plate over time after its manufacture.

[0138] Print life (after no ozone exposure): Each sample of the negative type lithographic printing plate original was subjected to 150 mJ / cm². 2The samples were exposed to infrared light at the exposure levels described above. These samples were not exposed to significant levels of ambient ozone. The exposed plates were then mounted on a Komori S-26 printing press operating at 8,000 rpm, and the press life (durability) was evaluated using a 1.3% aqueous solution of CDS503 (TOKYO PRINTING INK MFG) as dampening solution, an S-7400 blanket (Kin-yo-sha), OK Topcoat Matte N-grade paper (Oji paper) as printable paper, and K Magenta N-grade (DIC Graphics) as lithographic ink.

[0139] As printing continued and the number of printed sheets increased, the negative image recording layer of each negative-type lithographic printing plate, exposed to infrared light, gradually wore down, reducing the ink-receiving capacity of the layer. As a result, the lithographic printing ink density of the printed sheets decreased as printing continued. The print life (print durability) was determined by the number of copies produced when the reflectance density of the solid areas of the resulting copies decreased to 90% of the reflectance density observed at the start of printing. The greater the number of printed sheets produced when this decrease in reflectance density occurred, the better the print life (print durability) of the lithographic printing plate.

[0140] Print life (after exposure to ozone): Each separate sample of a negative-type lithographic printing plate was exposed to a controlled amount of ozone inside a commercially available humidity chamber, ETAC FX-430, with the ozone concentration controlled to 1 ppm and the chamber temperature controlled to 25°C. The following equipment was used to control the ozone concentration inside the humidity chamber.

[0141] A Kotohira KPO-T01 portable ozone generator was used as the ozone source, and a Kanomax Gasmaster Model 2750 was used as the ozone monitor inside the humidity chamber.

[0142] The ozone exposure times were 1 hour and 6 hours, corresponding to ozone exposure levels of 3,600 ppm·s and 21,600 ppm·s, respectively. In the unit "ppm·s," "ppm" is the unit of ozone concentration in parts per million by volume, and "s" represents the unit of time, which is seconds.

[0143] After this ozone exposure, the print life (print durability) of each sample of the negative type lithographic printing plate was evaluated in the same manner as described above.

[0144] The results of the on-press developability (DOP) and print life (print durability) tests are shown in Table V below.

[0145] [Table 5]

[0146] From the results shown in Table V, several conclusions can be drawn by those skilled in the art of lithographic printing. The negative lithographic printing plates manufactured according to Examples 1 to 12 of the present invention contained, in appropriate amounts, one or more urethane (meth)acrylates and one or more polyester (meth)acrylates required in a) two or more free radical polymerizable components in the negative infrared-sensitive image recording layer. These plates were observed to exhibit a desirable fast DOP for both NK7 and DT7 retention tests, as well as a desirable small DOP "gap" and a desirable long print life (print durability), regardless of the amount of exposure to ambient ozone.

[0147] The master plates of Comparative Examples 1, 2, 8, and 9 a) lacked the required polyester (meth)acrylate among two or more free radical polymerizable components, and instead contained further free radical polymerizable components SR494 and SR399, which were neither polyurethane (meth)acrylate nor polyester (meth)acrylate. The (UA+PEA) / AA values ​​in Table II were also below the required minimum of 75 wt%, and the UA / (UA+PEA) values ​​were above the specified upper limit of 90 wt%. These master plates showed the desired fast DOP after NK7 and DT7 retention tests and the desired small DOP "gap" when not exposed to ambient ozone. However, these master plates showed undesirable insufficient print life (print durability) after exposure to ambient ozone.

[0148] The master plates of Comparative Examples 3, 4, 10, and 11 contained, a) polyester (meth)acrylate in less than the specified amount relative to urethane (meth)acrylate in two or more free radical polymerizable components. The (UA+PEA) / AA values ​​in Table II were within the required range of at least 75% by weight, but the UA / (UA+PEA) values ​​exceeded the specified upper limit of 90% by weight. These master plates exhibited the desired long print life (print durability) regardless of exposure to ambient ozone. However, these master plates showed extremely slow and undesirable DOP after the DT7 retention test, as well as undesirable large DOP "gaps".

[0149] The master plates of Comparative Examples 5, 6, 12, and 13 contained, a) polyester (meth)acrylate in two or more free radical polymerizable components in an amount exceeding the specified amount relative to urethane (meth)acrylate. The (UA+PEA) / AA values ​​in Table II were within the required range of at least 75% by weight, but the UA / (UA+PEA) values ​​were below the specified lower limit of 35% by weight. These master plates exhibited the desired fast DOP after both NK7 and DT7 retention tests, and also showed the desired small DOP "gap". However, these master plates exhibited undesirable insufficient print life (print durability) regardless of the amount of ozone exposure.

[0150] The master plates of Comparative Examples 7 and 14 contained additional free radical polymerizable components, and therefore the total amount of urethane (meth)acrylate and polyester (meth)acrylate was below the required amount to be included in two or more free radical polymerizable components. The (UA+PEA) / AA value in Table II was below the required range of at least 75% by weight, but the UA / (UA+PEA) value was within the specified range of at least 35% to 90% by weight. These master plates showed the desired fast DOP after both NK7 and DT7 retention tests, and also showed the desired small DOP "gap". However, these master plates showed insufficient print life (print durability) after exposure to ambient ozone.

Claims

1. Aluminum-containing substrate and A negative-type infrared-sensitive image recording layer disposed on the aluminum-containing substrate and A negative type lithographic printing plate original, The aforementioned negative-type infrared-sensitive image recording layer, a) Two or more free radical polymerizable components, b) an initiator composition capable of generating free radicals, and c) Contains one or more infrared absorbing cyanine dyes, a) The above-mentioned free radical polymerizable components comprise one or more urethane (meth)acrylates and one or more polyester (meth)acrylates, wherein two or more free radical polymerizable components together constitute at least 75% to 100% by weight of all free radical polymerizable components. The weight ratio of one or more urethane (meth)acrylates to one or more polyester (meth)acrylates is 90:10 to 35:65 or less. Each of the one or more urethane (meth)acrylates comprises one or more urethane bonds and at least four acrylic acid ester groups or methacrylic acid ester groups. Each of the one or more polyester (meth)acrylates described above does not contain a urethane bond and has the following structure (I): X-OC(=O)-L-C(=O)-O-Y (I) [In the formula, L represents a single bond or a carbon chain, and X and Y independently represent a hydrogen atom or an organic group represented by the following structure (II), however, X and Y cannot both be hydrogen atoms.] (R) n (II) In the formula, A represents an n+1 valent organic group, and R represents a hydroxyl group or an acrylic acid ester group (CH₂). 2 =CHC(=O)O-), or methacrylate ester group (CH 2 = C(CH 3 A negative type lithographic printing plate original represented as )C(=O)O-), where n is an integer between 1 and 12, but not all R groups are hydroxyl groups.

2. The negative type lithographic printing plate according to claim 1, wherein the one or more urethane (meth)acrylates and one or more polyester (meth)acrylates together constitute at least 80% by weight of all of the two or more free radical polymerizable components.

3. The negative-type lithographic printing plate master according to claim 1 or 2, wherein the negative-type infrared-sensitive image recording layer is the outermost layer.

4. A negative-type lithographic printing plate according to any one of claims 1 to 3, which is press-developable using lithographic ink, dampening solution, or a combination of lithographic ink and dampening solution.

5. The L bond in structure (I) is a single bond, *CH 2 -CH 2 * group, *CH=CH* group, and the following groups Ia and Ib: 【Chemistry 1】 (Ia), and 【Chemistry 2】 (Ib) (In the formula, * represents a connection point with the rest of structure (I)) A negative type lithographic printing plate according to claim 3, selected from any of the following.

6. The negative-type lithographic printing plate according to any one of claims 1 to 5, wherein the negative-type infrared-sensitive image recording layer further comprises a particulate non-free radical polymerizable polymer binder.

7. The negative type lithographic printing plate according to any one of claims 1 to 6, wherein two or more free radical polymerizable components are present in an amount of at least 20% to 80% by weight relative to the total solid content of the negative type infrared-sensitive image recording layer.

8. The negative type lithographic printing plate master according to any one of claims 1 to 7, wherein the aluminum-containing substrate comprises two or more aluminum oxide layers and a hydrophilic polymer coating disposed on the outermost aluminum oxide layer.

9. A negative type lithographic printing plate according to any one of claims 1 to 8, wherein at least one of the one or more urethane (meth)acrylates comprises at least five acrylate groups or methacrylate groups.

10. The negative type lithographic printing plate according to any one of claims 1 to 9, wherein at least one of the one or more urethane (meth)acrylates comprises at least 10 acrylate groups or methacrylate groups.

11. The negative type lithographic printing plate according to any one of claims 1 to 10, wherein the a) two or more free radical polymerizable components further comprises one or more further free radical polymerizable components, none of which contain urethane bonds, none of which contain structures having at least two ester groups bonded to each other by bonds or carbon-carbon chains, but each of the one or more further free radical polymerizable components contains one or more (meth)acrylic acid ester groups, and the one or more further free radical polymerizable components are present in a total amount of less than 25% by weight of the total weight of the two or more free radical polymerizable components.

12. Each of the above one or more further free radical polymerizable components has a glycol ether bond [-O-M-O-] (where M represents -CH 2 -CH 2 - or CH 2 -CH(CH 3 )) and the negative-type lithographic printing plate precursor according to claim 11.

13. The one or more urethane (meth)acrylates described above have the following structure (III): L’-[NH-C(=O)-O-X’] p (III) [In the formula, L' represents a p-valent linking group, where p is an integer of 2 or 3, and X' is represented by the following structure (IV), -A’(R’) n’ (IV) In the formula, A' represents an n'+1 valent organic group, and R' represents a hydroxyl group or an acrylic acid ester group [CH 2 =CHC(=O)O-], or methacrylate ester group [(CH 2 = C(CH 3 A negative type lithographic printing plate according to any one of claims 1 to 12, represented by [C(=O)O-] independently, where n' is an integer between 1 and 6, but not all R' groups are hydroxyl groups].

14. The negative type lithographic printing plate according to claim 13, wherein L' is a hydrocarbon group.

15. The negative type lithographic printing plate according to claim 13, wherein L' is an aliphatic hydrocarbon group.

16. L' is hexamethylene [-(CH 2 ) 6 -] A negative type lithographic printing plate according to claim 13.

17. A' has the following structure (V): 【Transformation 3】 （V） (In the formula, * represents the connection point with the R' group.) A negative type lithographic printing plate according to claim 13, represented as [the original plate].

18. An aluminum-containing substrate comprising two or more aluminum oxide layers, A negative-type infrared-sensitive image recording layer is disposed as the outermost layer on the aluminum-containing substrate. A negative type lithographic printing plate original, The aforementioned negative-type infrared-sensitive image recording layer, a) Two or more free radical polymerizable components, b) An initiator composition that can generate free radicals and comprises an iodonium cation and a tetraarylborate anion, and c) Contains one or more infrared absorbing cyanine dyes, a) The above-mentioned free radical polymerizable components comprise one or more urethane (meth)acrylates and one or more polyester (meth)acrylates, wherein two or more free radical polymerizable components together constitute at least 80% to 100% by weight of all free radical polymerizable components. The weight ratio of one or more urethane (meth)acrylates to one or more polyester (meth)acrylates is 75:25 to 50:50 or less. Each of the one or more urethane (meth)acrylates comprises one or more urethane bonds and at least four acrylic acid ester groups or methacrylic acid ester groups, and has the following structure (III): L’-[NH-C(=O)-O-X’] p (III) [In the formula, L' represents a p-valent linking group, where p is an integer of 2 or 3, and X' is represented by the following structure (IV), -A’(R’) n’ (IV) In the formula, A' represents an n'+1 valent organic group, and R' represents a hydroxyl group or an acrylic acid ester group [CH 2 =CHC(=O)O-], or methacrylate ester group [(CH 2 = C(CH 3 The R' groups are represented independently as )C(=O)O-, where n' is an integer between 1 and 6, but not all R' groups are hydroxyl groups. Each of the one or more polyester (meth)acrylates described above does not contain a urethane bond and has the following structure (I): X-OC(=O)-L-C(=O)-O-Y (I) [In the formula, L represents a single bond, or *CH] 2 -CH 2 * group, *CH=CH* group, and the following groups Ia and Ib: 【Chemistry 4】 (Ia), and 【Transformation 5】 (Ib) (In the formula, * represents a connection point with the rest of structure (I)), and X and Y independently represent a hydrogen atom or an organic group represented by the following structure (II), however, X and Y cannot both be hydrogen atoms. (R) n (II) In the formula, A represents an n+1 valent organic group, and R represents a hydroxyl group or an acrylic acid ester group (CH₂). 2 =CHC(=O)O-), or methacrylate ester group (CH 2 = C(CH 3 A negative type lithographic printing plate original represented as )C(=O)O-), where n is an integer between 1 and 12, but not all R groups are hydroxyl groups.

19. A method for providing a lithographic printing plate, A) A step of exposing a negative type lithographic printing plate according to any one of claims 1 to 18 to an image-like light with image-forming infrared light to provide exposed regions and unexposed regions in the negative type infrared-sensitive image recording layer, B) A step of removing the unexposed region in the negative infrared-sensitive image recording layer from the aluminum-containing substrate. Methods that include...

20. The method according to claim 19, comprising the step of removing the unexposed region in the negative infrared-sensitive image recording layer from the aluminum-containing substrate on the machine using a lithographic ink, dampening solution, or a combination of a lithographic ink and dampening solution.

Images