A thermal-sensitive resin, an environmentally friendly thermal-sensitive plate and a preparation method thereof

Abstract

The present invention provides a thermosensitive resin, an environmentally friendly thermosensitive plate and a preparation method thereof. The thermosensitive resin provided in the present application is an important binder in the thermosensitive coating forming the thermosensitive layer, namely, a functional film-forming resin, which can improve the water or fountain solution developing ability of the plate and the ability to resist the erosion of chemicals in the ink, so as to realize the image layer having a thermosetting urethane bond network structure, which can increase the wear resistance of the plate coating and improve the printing resistance of the plate. The environmentally friendly thermosensitive plate provided in the present application is hydrophilic and can realize water development or fountain solution development. It is a green and environmentally friendly thermosensitive plate. Through the thermosensitive resin, crosslinking agent and thermochromic dye with special structure, the sensitivity of the thermosensitive plate is improved, the dot restoration accuracy of the plate is improved; the printing resistance of the plate is improved, and the color restoration uniformity of the image layer is improved by improving the exposure tolerance; the developability and printing resistance of the plate are improved; the platemaking contrast of the plate is improved, and the problem of automatic plate recognition by computer is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of lithography, and in particular relates to a thermosensitive resin, an environmentally friendly thermosensitive plate and a preparation method thereof. Background Art

[0002] For a long time, my country's printing industry, especially the packaging printing industry, has been developing in an extensive manner with high consumption and high pollution. However, with the fragility of the ecosystem in which humans live, the deterioration of the environment, and the high shortage of resources, both the stock of resources and the carrying capacity of the environment have been overwhelmed. Printing and post-press processing technologies have pollution problems on the environment. For example, the developer used in pre-press plate making contains toxic chemical components, and ordinary inks and car wash water used in printing contain heavy metal elements such as lead, chromium, and mercury, which cause certain harm to human health. Therefore, it is urgent to vigorously promote green printing.

[0003] Green printing appeared in the late 1980s in Western countries represented by Japan, the United States, and Germany. After more than 20 years of development, it has now entered the stage of practical application from the stage of conceptual discussion. It has made great progress and matured in terms of concepts, technical standards, equipment technology, raw and auxiliary materials, and software applications. In developed countries in Europe and the United States, green printing is a reflection of their level of scientific and technological development, and it is also an effective means to replace traditional printing methods that cause environmental pollution and high energy consumption.

[0004] Green printing refers to the use of environmentally friendly materials and processes, which produces less pollution during the printing process, saves resources and energy, and is easy to recycle and reuse after the printed products are discarded, can be naturally degraded, and has little impact on the ecological environment. Green printing requires coordination with the environment, including the use of environmentally friendly printing materials, clean printing production processes, the safety of printed products to users, and the recycling and recyclability of printed products. That is, the entire life cycle of printed products, from raw material selection, production, use, recycling, etc., should meet environmental protection requirements.

[0005] At present, green printing leads the development direction of the printing industry with its powerful influence. Prepress platemaking has entered the CTP era, so environmentally friendly treatment-free CTP plates have become a hot topic in the industry. From a broad perspective, treatment-free CTP plates refer to plates that can be printed on the machine without any subsequent processing steps after being exposed and imaged on the direct platemaking equipment, and of course do not require chemical development and washing treatment. They are truly treatment-free plates. From a narrow perspective, it means that plates do not require chemical development treatment after being exposed and imaged on the direct platemaking machine, but there will be individual non-chemical processing steps, such as the removal of plate ablation waste, coating of protective glue, and other processing work.

[0006] Developing green and environmentally friendly printing consumables, especially green and environmentally friendly printing plates, is the top priority in developing green printing.

[0007] Thermal CTP plates have been widely used, from the first generation of preheated negative thermal plates to the second generation of mature preheat-free positive thermal plates, and the third generation of thermal plate technology is aimed at free treatment. Currently, the development of printing plate materials is moving towards green and environmental protection. The world's major printing plate manufacturers have successively launched CTP plates without (low) chemical treatment.

[0008] Classification of processing-free CTP plates: At present, there are many processing-free CTP plates on the market. According to the characteristics of the plates, they can be divided into the following two categories:

[0009] (1) Completely processing-free CTP plates. Refers to CTP plates that can be directly printed on the machine after imaging on the platemaking equipment. According to different imaging methods, they can be mainly divided into ablation-type processing-free CTP plates and thermo-polar processing-free CTP plates.

[0010] (2) Environmentally friendly, developer-free CTP plates. After the CTP plates are exposed and imaged on the plate-making machine, they must be developed before printing. This process does not require chemical developers, and can be developed by washing with clean water or by protecting the printing plate with glue. Alternatively, after the CTP plates are exposed and imaged on the plate-making machine, they are developed on the printing press using the wetting effect of the fountain solution to remove the film on the non-image part.

[0011] There are many technical routes for developing green, environmentally friendly and free-processing CTP plates, which can be divided into thermal ablation technology, phase change technology and hot melt technology. Thermal ablation technology refers to the infrared laser energy ablating the oleophilic coating to expose the hydrophilic surface of the aluminum plate to form a hydrophilic area; phase change technology refers to the laser energy causing the polymer to undergo hydrophilic-oleophilic conversion to achieve ink-water separation; hot melt technology is the laser energy that causes the thermoplastic polymer particles dispersed in the cross-linked hydrophilic layer to melt, changing from hydrophilic to hydrophobic-oleophilic. .

[0012] Development of chemical-free CTP plate technology: EP0980754 introduces decarboxylation to achieve hydrophilic-hydrophobic conversion technology, but the printing resistance is poor. WO94 / 23954 introduces hot melt micro-gel technology, but it is easy to get dirty; US4004924 introduces a mixture of thermoplastic hydrophobic particles and hydrophilic binder, which is also not printing-resistant; EP 2006-5-24 06114475.4 introduces a hot-melt thermoplastic particle, which is easy to contaminate the fountain solution; US 2005-8-3 11 / 196,124 introduces a one-dimensional linear structure hydrophilic adhesive, which has low printing resistance; US 2006-7-27 11 / 494,235 introduces a printing plate precursor containing hydrophilic groups and esterified allyl groups, but the ester group is not resistant to ink erosion.

[0013] At present, environmentally friendly thermal plates are divided into two types: double-layer plates and single-layer plates.

[0014] Double-layer environmentally friendly thermal plates generally use a double-bond free radical imaging mechanism. In order to reduce the inhibitory effect of oxygen on free radical reactions, an oxygen barrier protective layer is set on the plate. The advantage is that the plate has high printing resistance, but the disadvantage is that it requires double-layer coating, high production process control requirements, low product yield, and the processing of defective products produced in the production process will cause environmental pollution, which indirectly increases environmental pressure.

[0015] Single-layer environmentally friendly thermal plates generally adopt a non-oxygen inhibition imaging mechanism, and the plate does not need to be set with an oxygen barrier protective layer. Its advantages are single-layer coating, simple plate production process, high yield rate, and high press run. Its disadvantages are high requirements on the imaging ability of the imaging material. Insufficient imaging ability of the imaging material often affects the environmental performance and press run of the thermal plate.

[0016] At present, common problems with environmentally friendly thermal plates are: 1. Problems with dot reproduction accuracy; 2. Problems with low chemical development or on-press development capabilities; 3. Problems with color reproduction uniformity; 4. Problems with press durability; 5. Problems with platemaking contrast.

[0017] The problem of dot reproduction accuracy is mainly reflected in the accurate reproduction of image dots; the problem of low chemical development or on-press development ability is mainly reflected in whether the thermal plate can be washed and developed with water after being scanned and exposed by the thermal CTP platemaking machine, or directly loaded on the printing press for development and printing with the printing press fountain solution; the problem of color reproduction uniformity is mainly reflected in the amount of ink of different colors absorbed by the printing plate, and the difference in ink amount is directly manifested as the color difference of the printed product; the problem of platemaking contrast is reflected in whether the image cross lines can be automatically recognized by the printing press computer system after the thermal plate is scanned and exposed by the thermal CTP platemaking machine. Summary of the invention

[0018] In order to solve the above problems, the present invention provides a thermosensitive resin, an environmentally friendly thermosensitive plate and a preparation method thereof. The thermosensitive resin provided in the present application is an important binder in the thermosensitive coating forming the thermosensitive layer, namely, a functional film-forming resin, which can improve the water or fountain solution developing ability of the plate and the ability to resist the erosion of chemicals in the ink, and realize that the image layer has a thermosetting urethane bond network structure, which can increase the wear resistance of the plate coating and improve the printing resistance of the plate. The environmentally friendly thermosensitive plate provided in the present application is hydrophilic and can realize water development or fountain solution development. It is a green and environmentally friendly thermosensitive plate. Through the thermosensitive resin, crosslinking agent and thermochromic dye with a special structure, the sensitivity of the thermosensitive plate is improved, the dot restoration accuracy of the plate is improved; the printing resistance of the plate is improved, and the color restoration uniformity of the image layer is improved by increasing the exposure tolerance; the developability and printing resistance of the plate are improved; the platemaking contrast of the plate is improved, and the problem of automatic plate recognition by the computer is solved.

[0019] The object of the present invention is achieved in the following manner: the heat-sensitive resin is a ternary free radical copolymer of monomer a: methacrylamide, monomer b: hydroxyethyl acrylamide and monomer c: 3,4-epoxycyclohexyl methacrylate, wherein the weight proportion of methacrylamide units in the copolymer is 40-80% (weight percentage), the weight proportion of hydroxyethyl acrylamide units in the copolymer is 10-30% (weight percentage), and the weight proportion of 3,4-epoxycyclohexyl methacrylate units in the copolymer is 10-30% (weight percentage).

[0020] When designing a thermal plate, the first thing to consider is the thermal coating of the plate. The thermal coating requires an important binder, namely a functional film-forming resin. The resin can form a film after the coating liquid of the thermal coating is dried, so that the thermal coating is attached to the hydrophilic carrier. The binder can be in a solution state or an emulsion state. At the same time, the functional film-forming resin contains functional groups and plays a special functional role. The thermal resin described in the present invention is such a binder.

[0021] The thermosensitive resin of the present invention contains a hydrophilic structural unit, a methacrylamide unit. After infrared laser scanning and imaging, the molecular weight of the thermosensitive layer increases sharply, making the coating more solid. The coating after laser thermal exposure is difficult to be removed by water and ink; the excess coating in the unexposed blank area is easily removed by water due to the presence of amide groups, and the exposed blank area is a hydrophilic aluminum plate base, achieving the environmental protection purpose of no pollution discharge during the platemaking process. The weight percentage content of the methacrylamide unit in the copolymer is 40-80% (weight percentage).

[0022] The thermosensitive resin contains hydroxyethyl acrylamide structural units. Hydroxyethyl acrylamide has good hydrophilicity and oil resistance, which can improve the water or fountain solution developing ability of the plate and the ability to resist the chemical erosion in the ink. At the same time, the hydroxyl group in hydroxyethyl acrylamide can react with the isocyanate group released by the crosslinking agent to crosslink, so that the image layer has a thermosetting urethane bond network structure, which has higher printing resistance than traditional linear polymerized thermoplastic plates. The weight percentage of hydroxyethyl acrylamide copolymer unit b in the copolymer is 10-30% (weight percentage).

[0023] The special thermosensitive resin designed by the present invention contains epoxy bonds on cyclohexyl groups, and has the ability of efficient cationic crosslinking. Laser heat energy is transferred to the thermal initiator through the thermochromic dye, and the thermal initiator generates cations by heterolysis, so that the epoxy bonds on the cyclohexyl groups in the special thermosensitive resin and the epoxy bonds in the crosslinking agent are crosslinked and polymerized. The epoxy bonds on the cyclohexyl groups contained in the thermosensitive resin of the present invention have the ability of ultra-high cationic crosslinking, and the cyclohexyl groups have certain rigidity, which can increase the wear resistance of the plate coating and improve the printing resistance of the plate. The weight percentage content of the copolymerization unit c containing the epoxy bonds on the cyclohexyl groups in the multi-polymer is 10-30% (weight percentage).

[0024] The thermosensitive resin of the present invention is synthesized by solution or emulsion copolymerization, and the copolymerization reaction can be random copolymerization or block copolymerization, preferably random copolymerization. The polymerization initiator includes peroxides such as di-tert-butyl peroxide, benzoyl peroxide, persulfates such as potassium persulfate, ammonium persulfate, azo compounds such as azobisisobutyronitrile, etc., and the copolymerization method is preferably solution polymerization.

[0025] The reaction solvent that can be used includes water, methanol, ethanol, n-propanol, isopropanol, butanol, acetone, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, dimethylacetamideacetone, methyl ethyl ketone, cyclohexane, ethylene dichloride, toluene, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol dimethyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, acetylacetone, diacetone alcohol, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol isopropyl ether, ethylene glycol butyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, dimethyl sulfoxide, methyl lactate and ethyl lactate, or the like, or a mixture thereof. The copolymerization temperature is preferably 40-100°C, and most preferably 60-90°C.

[0026] The heat-sensitive resin of the present invention has a weight average molecular weight of 4000-150000 and a glass transition temperature of 110-130°C.

[0027] A green and environmentally friendly thermosensitive plate, the plate material comprises a hydrophilic carrier and a thermosensitive layer, wherein the thermosensitive layer contains the above-mentioned thermosensitive resin, crosslinking agent, thermal initiator and thermochromic dye; the thermosensitive resin accounts for 50-90% of the total solid content of the thermosensitive layer, preferably 60-80%.

[0028] The environmentally friendly thermal plate of the present invention improves the performance of the plate material by adding a special cross-linking agent, which has the following structure (code: cross-linking agent P):

[0029]

[0030] The environmentally friendly thermal plate of the present invention improves the imaging ability of the plate by adding a special crosslinking agent, and the plate has a dual imaging mechanism of cationic polymerization and amination reaction. Laser thermal energy transfers energy to the thermal initiator through the thermal dye, and the cations generated by the heterolysis of the thermal initiator cause the epoxy bonds in the crosslinking agent and the epoxy bonds on the cyclohexyl group in the special thermal resin to undergo cationic network crosslinking, thereby realizing cationic network thermal imaging; at the same time, the plate has the ability of amination network thermal imaging, and the crosslinking agent removes the caprolactam group at the tail end under the action of laser heat, releasing the active isocyanate group, and the active isocyanate group can react with the hydroxyl group on the special thermal resin to undergo amination reaction, thereby forming a thermosetting ammonia bond network structure image, thereby improving the sensitivity and printing durability of the plate. The crosslinking agent accounts for 5%-30% of the total solid content of the thermal layer composition, preferably 10%-20%.

[0031] The thermal initiator in the heat-sensitive layer of the plate is described in detail below.

[0032] The plate has cationic polymerization imaging ability, so the thermal initiator here is also called a cationic photopolymerization initiator, and the thermal initiator is selected from onium salts, such as sulfonium salts, iodonium salts, etc. Suitable onium salts include sulfonium salts, oxysulfonium salts, oxysulfonium salts, sulfoxide salts, diazonium salts and halogen onium salts such as iodonium salts. Specific examples of suitable onium salts include diphenyliodonium chloride, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, [4-[(2-hydroxytetradecyl-oxy]-phenyl]phenyliodonium hexafluoroantimonate, triphenylsulfonium iodonium tetrafluoroborate, triphenylsulfonium iodonium octylsulfate, 2-methoxy-4-aminophenyl diazonium hexafluorophosphate, phenoxyphenyl diazonium hexafluoroantimonate, and the like. The cationic photopolymerization initiator of the present invention is selected from one or more iodonium salts and sulfonium salts. Its thermal decomposition temperature is 150-200° C. The cationic photopolymerization initiator preferably accounts for 1%-15% of the dry weight of the coating film (i.e., the total solid content of the heat-sensitive layer composition) in the heat-sensitive layer, preferably 1%-10%.

[0033] The components in the heat-sensitive layer of the heat-sensitive plate of the present invention are described in detail below: Thermochromic dye.

[0034] The thermochromic dye component in the thermosensitive plate composition of the present invention has the functions of both infrared dye and laser color change, and mainly plays the role of energy transfer and color change. The heat of the infrared laser transfers the laser energy to the thermal initiator through the thermochromic dye, and the thermal initiator generates the epoxy polymerization in the cationic initiation system to realize thermal imaging. The laser energy is converted into thermal energy by the thermochromic dye, and the caprolactam group at the end of the crosslinking agent is removed, and the active isocyanate group is released. The active isocyanate group can react with the hydroxyl group on the special thermosensitive resin to undergo an amine esterification reaction, thereby forming a thermosetting amine bond network structure image. At the same time, the thermochromic dye has the function of laser color change, and a closed-loop reaction can occur under the action of laser heat, thereby changing the color, and this color change is irreversible, realizing the contrast presentation of the plate material in a non-developing manner, which is conducive to the printing operator to check the plate with the naked eye to detect the image defects of the printing plate, and can be automatically positioned and identified by a modern highly intelligent printing press, realizing automatic intelligent plate loading. The thermochromic dye of the present invention can be a thermochromic azamethine dye. A thermochromic azamethine dye with an absorption peak in the range of 730-880 nm may be selected, and an azamethine dye with the following structure (code: thermochromic dye D) is preferred:

[0035]

[0036] The thermochromic dye in the thermosensitive layer preferably accounts for 1%-15% of the dry weight of the coating film, preferably 5%-10%.

[0037] Finally, the hydrophilic carrier of the heat-sensitive plate of the present invention is described in detail.

[0038] The heat-sensitive layer composition of the present invention needs to be coated on the hydrophilic carrier of the heat-sensitive plate, and the carrier of the heat-sensitive plate includes a metal plate base such as a copper plate base, an aluminum plate base, etc. The hydrophilic carrier selected by the present invention is an aluminum plate base after electrolytic roughening, anodizing, and sealing treatment, with an average center line roughness of 0.3-0.6um, and is obtained by electrolytic roughening. The aluminum plate base is more than 99% aluminum, 0.1%-0.5% iron, 0.03%-0.3% silicon, 0.003%-0.03% copper, and 0.01%-0.1% titanium. The electrolytic roughening electrolyte can be an aqueous solution of acid, alkali or salt. First, the aluminum plate is placed in an aqueous solution of 1%-30% sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, etc., and chemically corroded at a temperature of 20-80°C for 5-250 seconds. Then it is neutralized in 10%-30% nitric acid or sulfuric acid at a temperature of 20-70°C to remove the ash. At a temperature of 10-60°C, use a rectangular wave, a mezzanine wave or a sine wave with alternating positive and negative currents at 5-100A / dm 2 The current density is 10-300 seconds in a nitric acid or hydrochloric acid electrolyte. Then anodizing is performed. Anodizing is usually done by sulfuric acid method, with a sulfuric acid concentration of 5-30% and a current density of 1-15A / dm2 The oxidation temperature is 20-60°C and the oxidation time is 5-250 seconds to form 1-10g / m 2 The oxide film is then sealed. Various methods can be used to seal the pores, preferably sealing 50-80% of the volume of the oxide film micropores. Finally, polyvinylphosphonic acid is coated on the aluminum plate treated as above with a thickness of 3 mg / m 2 .

[0039] The heat-sensitive layer composition of the present invention may also be added with some other necessary auxiliary agents during production, such as solvents, room-temperature thermal polymerization inhibitors, surfactants, etc. Solvents are mainly used to prepare heat-sensitive coating photosensitive liquids, including: alcohols, ketones, esters, ethers, amides, aromatic solvents, ethylene dichloride, tetrahydrofuran, etc. Solvents can be used in pure or mixed forms; room-temperature thermal polymerization inhibitors are used to prevent the plate from polymerizing at room temperature and improve the room-temperature stability of the plate. Thermal polymerization inhibitors include: hydroquinone, nitroxide free radical piperidinol, p-methoxyphenol, di-tert-butyl-p-cresol, pyrogallol, tert-butylcatechol, benzoquinone, 4,4'-thiobis-(3-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-methyl-16-tert-butylphenol), and primary cerium salt of N-nitrosophenylhydroxylamine, etc.; adding a layer colorant is to increase the image density of the heat-sensitive plate after platemaking, so as to facilitate visual inspection or image analysis of the heat-sensitive plate after platemaking. Analytical measuring equipment is used to measure the properties of the plate, which include: methyl violet, ethyl violet, crystal violet, crystal violet, Victoria blue, oil green, oil blue, oil yellow, rhodamine B, methyl violet, malachite green, methylene blue, triazines, etc.; surfactants need to be added to the coating, and non-ionic surfactants, amphoteric surfactants, silicon-containing surfactants, fluorine-containing surfactants, etc. can be selected, such as betaines, stearic acid glyceryl esters, sorbic acid palm oil esters, polysiloxanes, and polyfluoroalkyl ethers.

[0040] The heat-sensitive layer composition of the present invention is usually coated by techniques known in the art (e.g., knife coating, blade coating, bar coating, roller coating, press coating, etc.).

[0041] Compared with the prior art, the thermosensitive resin provided in the present application is an important binder in the thermosensitive coating that forms the thermosensitive layer, namely, a functional film-forming resin. The resin can form a film after the coating liquid of the thermosensitive coating is dried, so that the thermosensitive coating is attached to the hydrophilic carrier to form a thermosensitive layer. The binder can be in a solution state or an emulsion state. At the same time, the functional film-forming resin contains methacrylamide and hydroxyethylated acrylamide hydrophilic units, which can achieve water development or on-machine development, and is a green and environmentally friendly thermosensitive plate. In addition, it can improve the water or fountain solution development ability of the plate and the ability to resist the erosion of chemicals in the ink, and realize that the image layer has a thermosetting urethane bond network structure, which has a higher printing resistance than the traditional linear polymerized thermoplastic plate, can increase the wear resistance of the plate coating, and improve the printing resistance of the plate.

[0042] The invention adopts the thermosensitive resin, crosslinking agent and thermochromic dye of the special structure of the present application, improves the sensitivity of the thermosensitive plate through the dual imaging mechanism of cationic polymerization and urethanization reaction, and improves the dot restoration accuracy of the plate; introduces a thermosetting high wear-resistant urethane bond network crosslinking structure through the crosslinking agent, improves the crosslinking density of the image layer and improves the printing endurance of the plate, and improves the color restoration uniformity of the image layer by improving the exposure tolerance; improves the developability and printing endurance of the plate by introducing an amide group; adopts a thermochromic dye of a special structure to improve the platemaking contrast of the plate, and solves the problem of automatic plate recognition by computers; at the same time, the plate is hydrophilic and can realize water development or fountain solution development, and is a green and environmentally friendly thermosensitive plate. DETAILED DESCRIPTION

[0043] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that this embodiment is only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Technical personnel skilled in the art can make some non-essential improvements and adjustments based on the above-mentioned contents of the present invention.

[0044] The following are synthesis examples of the present invention, but the present invention is not limited to the following examples.

[0045] The raw materials can be obtained from the following companies: methacrylamide, hydroxyethyl acrylamide: Shanghai Bailingwei Technology; 3,4-epoxycyclohexyl methacrylate CMA: Mitsubishi Rayon Chemical of Japan; dimethylacetamide DMAC: Lanzhou Petrochemical, azobisisobutylcyanide AIBN: Tianjin Fuchen Chemical Reagent; benzoyl peroxide BPO: Laiwu Kangxin Reagent.

[0046] Part 1: Synthesis Examples of Special Thermosensitive Resin (Code L) L1-L11

[0047] Example 1 (Special Thermosensitive Resin L1)

[0048] In a 500 ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection, add 300 g of dimethylacetamide, 80 g (80 wt%) of methacrylamide, 10 g (10 wt%) of hydroxyethyl acrylamide, 10 g (10 wt%) of 3,4-epoxycyclohexyl methacrylate and 1 g of azobisisobutyronitrile, stir evenly, react at 70°C for 8 hours, cool down to terminate the reaction, and the reaction stock solution can be used directly.

[0049] Example 2 (Special Thermosensitive Resin L2)

[0050] In a 500 ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection, add 300 g of dimethylacetamide, 70 g (70 wt%) of methacrylamide, 20 g (20 wt%) of hydroxyethyl acrylamide, 10 g (10 wt%) of 3,4-epoxycyclohexyl methacrylate and 1 g of azobisisobutyronitrile, stir evenly, react at 70°C for 8 hours, cool down to terminate the reaction, and the reaction stock solution can be used directly.

[0051] Example 3 (Special Thermosensitive Resin L3)

[0052] In a 500 ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection, add 300 g of dimethylacetamide, 70 g (70 wt%) of methacrylamide, 10 g (10 wt%) of hydroxyethyl acrylamide, 20 g (20 wt%) of 3,4-epoxycyclohexyl methacrylate and 1 g of azobisisobutyronitrile, stir evenly, react at 70°C for 8 hours, cool down to terminate the reaction, and the reaction stock solution can be used directly.

[0053] Example 4 (Special Thermosensitive Resin L4)

[0054] In a 500 ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection, add 300 g of dimethylacetamide, 70 g (70 wt%) of methacrylamide, 15 g (15 wt%) of hydroxyethyl acrylamide, 15 g (15 wt%) of 3,4-epoxycyclohexyl methacrylate and 1 g of azobisisobutyronitrile, stir evenly, react at 70°C for 8 hours, cool down to terminate the reaction, and the reaction stock solution can be used directly.

[0055] Example 5 (Special Thermosensitive Resin L5)

[0056] In a 500 ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection, add 300 g of dimethylacetamide, 60 g (60 wt%) of methacrylamide, 30 g (30 wt%) of hydroxyethyl acrylamide, 10 g (10 wt%) of 3,4-epoxycyclohexyl methacrylate and 1 g of azobisisobutyronitrile, stir evenly, react at 70°C for 8 hours, cool down to terminate the reaction, and the reaction stock solution can be used directly.

[0057] Example 6 (Special Thermosensitive Resin L6)

[0058] In a 500 ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection, add 300 g of dimethylacetamide, 60 g (60 wt%) of methacrylamide, 10 g (10 wt%) of hydroxyethyl acrylamide, 30 g (30 wt%) of 3,4-epoxycyclohexyl methacrylate and 1 g of azobisisobutyronitrile, stir evenly, react at 70°C for 8 hours, cool down to terminate the reaction, and the reaction stock solution can be used directly.

[0059] Example 7 (Special Thermosensitive Resin L7)

[0060] In a 500 ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection, add 300 g of dimethylacetamide, 60 g (60 wt%) of methacrylamide, 20 g (20 wt%) of hydroxyethyl acrylamide, 20 g (20 wt%) of 3,4-epoxycyclohexyl methacrylate and 1 g of azobisisobutyronitrile, stir evenly, react at 70°C for 8 hours, cool down to terminate the reaction, and the reaction stock solution can be used directly.

[0061] Example 8 (Special Thermosensitive Resin L8)

[0062] In a 500 ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection, add 300 g of dimethylacetamide, 50 g (50 wt%) of methacrylamide, 20 g (20 wt%) of hydroxyethyl acrylamide, 30 g (30 wt%) of 3,4-epoxycyclohexyl methacrylate and 1 g of azobisisobutyronitrile, stir evenly, react at 70°C for 8 hours, cool down to terminate the reaction, and the reaction stock solution can be used directly.

[0063] Example 9 (Special Thermosensitive Resin L9)

[0064] In a 500 ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection, add 300 g of dimethylacetamide, 50 g (50 wt%) of methacrylamide, 30 g (30 wt%) of hydroxyethyl acrylamide, 20 g (20 wt%) of 3,4-epoxycyclohexyl methacrylate and 1 g of azobisisobutyronitrile, stir evenly, react at 70°C for 8 hours, cool down to terminate the reaction, and the reaction stock solution can be used directly.

[0065] Example 10 (Special Thermosensitive Resin L10)

[0066] In a 500 ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection, add 300 g of dimethylacetamide, 50 g (50 wt%) of methacrylamide, 25 g (25 wt%) of hydroxyethyl acrylamide, 25 g (25 wt%) of 3,4-epoxycyclohexyl methacrylate and 1 g of azobisisobutyronitrile, stir evenly, react at 70°C for 8 hours, cool down to terminate the reaction, and the reaction stock solution can be used directly.

[0067] Example 11 (Special Thermosensitive Resin L11)

[0068] In a 500 ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection, add 300 g of dimethylacetamide, 40 g (40 wt%) of methacrylamide, 30 g (30 wt%) of hydroxyethyl acrylamide, 30 g (30 wt%) of 3,4-epoxycyclohexyl methacrylate and 1 g of azobisisobutyronitrile, stir evenly, react at 70°C for 8 hours, cool down to terminate the reaction, and the reaction stock solution can be used directly.

[0069] Part II: Synthesis of crosslinker P

[0070] The raw materials can be obtained from the following companies: dicyclohexylmethane diisocyanate: Bayer Chemical, Germany; 3-ethyl-3-oxetane methanol: Nantong Xinashi New Materials Co., Ltd.; ε-caprolactam: Shanghai Bailingwei Technology; dibutyltin dilaurate: Tianjin Chemical Reagent Plant No. 2; dimethylacetamide: Lanzhou Petrochemical.

[0071] In a 1000 ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, condensation reflux and drying tube, 262.3 g of dicyclohexylmethane diisocyanate, 3 g of dibutyltin dilaurate and 491.7 g of dimethylacetamide were added, heated to 50°C, 116.2 g of 3-ethyl-3-oxetane methanol was added dropwise for 30 minutes, and the mixture was reacted for 1 hour. Then 113.2 g of ε-caprolactam was added and the mixture was reacted for 20 minutes. The mixture was reacted in an ice-water bath for 48 hours until the peak of the active isocyanate group at 2275 disappeared as detected by infrared spectroscopy, and a dimethylformamide solution of compound P with a solid content of 50% was obtained. The solution can be used directly according to the solid content.

[0072] Comparative Examples 1-5 (Synthesis of similar Agfa polymers A1-A5):

[0073] According to Agfa patent EP 2006-5-24 06114475.4, a polymer similar to Agfa is synthesized by solution polymerization, but the polymer does not contain hydrophilic groups. The polymer structure is:

[0074]

[0075] A1: Add 400 g methyl ethyl ketone and 5 g sodium dodecyl sulfate to a 1000 ml four-necked flask equipped with temperature control heating, mechanical stirring, condensation reflux and nitrogen protection. Add 80 g (80 wt%) ST (styrene), 20 g (20 wt%) AN (acrylonitrile) and 0.7 g AIBN (azobisisobutyronitrile) dropwise at 80°C for 0.5 hour. After reacting for 7.5 hours, add 0.3 g AIBN (azobisisobutyronitrile) and continue to react for 12 hours before the reaction is completed.

[0076] Change the feed ratio to synthesize similar Agfa polymers:

[0077] A2(ST:60,AN:40), A3(ST:50,AN:50), A4(ST:40,AN:60),A5(ST:20,AN:80).

[0078] Comparative Examples 6-10 (Synthesis of similar Kodak polymers K1-K5):

[0079] According to Kodak patent US 2005-8-3 11 / 196, a polymer similar to Agfa is synthesized by solution polymerization. The polymer contains hydrophilic groups but no epoxy groups. The polymer structure is:

[0080]

[0081] K1: Add 400 g of methyl ethyl ketone to a 1000 ml four-necked flask equipped with temperature control heating, mechanical stirring, condensation reflux and nitrogen protection devices, and drop 80 g (80 wt%) ST (styrene), 10 g (10 wt%) AN (acrylonitrile), 10 g0.7 g (10 wt%) PEGMA45 (polyethoxy methacrylate, degree of polymerization N=45), and AIBN (azobisisobutyronitrile) at 80°C for 0.5 hour. After reacting for 7.5 hours, add 0.3 g of AIBN (azobisisobutyronitrile) and continue to react for another 12 hours before ending.

[0082] Change the feed ratio and reaction concentration to synthesize similar Kodak polymers:

[0083] K2(ST / AN / PEFMA=70 / 15 / 15,N=55),K3(ST / AN / PEFMA=60 / 20 / 20,N=45), K4(ST / AN / PEFMA=50 / 40 / 100,N=55), K5(ST / AN / PEFMA=30 / 60 / 10,N=65)

[0084] The thermochromic dye D with the above structure can be purchased from Shenyang Research Institute of Chemical Industry.

[0085] The infrared absorbing dye ADS830 used in the comparative example can be purchased from Qingdao Lanfan New Materials Co., Ltd., and its structure is as follows:

[0086]

[0087] Example 1

[0088] Preparation of the plate base: A1050 rolled aluminum plate with a purity of 99.5% and a thickness of 0.3 mm was etched in a 5% sodium hydroxide aqueous solution at 70°C for 20 seconds, rinsed with running water, and immediately neutralized with a 1% nitric acid aqueous solution. Then, in a 1% hydrochloric acid aqueous solution, a sine wave AC current of 50 A / dm was used at 40°C. 2 The surface was electrolytically roughened at a current density of 15A / dm for 16 seconds, then neutralized with a 5% sodium hydroxide aqueous solution at 40°C for 10 seconds and washed with water. Finally, a 20% sulfuric acid aqueous solution was used at 30°C with a current density of 15A / dm 2 The current density was 20 seconds for anodization and then washed with water. The holes were sealed with a 5% sodium silicate aqueous solution at 80°C for 18 seconds, washed with water and dried. The average center line roughness of the plate obtained was 0.5 μm and the oxide film weight was 3.0 g / dm 2 .

[0089] Thermal layer coating: The following photosensitive liquid (i.e., thermal layer composition) is extruded and coated on the hydrophilized substrate, and then dried at 100°C for 60 seconds to obtain a 10 mg / dm 2 The photosensitive solution uses the following components (each component is by weight):

[0090] Special thermosensitive resin L1 90

[0091] Crosslinker P 5

[0092] Diaryl iodonium hexafluorophosphate salt 3

[0093] Thermochromic Dye D 2

[0094] Basic Brilliant Blue 0.5

[0095] Surfactant (BYK306) 0.5

[0096] Methyl Ethyl Ketone 200

[0097] 1-Methoxy-2-propanol 700

[0098] Example 2

[0099] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0100] Special thermosensitive resin L1 85

[0101] Crosslinker P 10

[0102] Diaryl iodonium hexafluorophosphate salt 3

[0103] Thermochromic Dye D 2

[0104] Basic Brilliant Blue 0.5

[0105] Surfactant (BYK306) 0.5

[0106] Methyl Ethyl Ketone 200

[0107] 1-Methoxy-2-propanol 700

[0108] Example 3

[0109] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0110] Special thermosensitive resin L1 80

[0111] Crosslinker P 15

[0112] Diaryl iodonium hexafluorophosphate salt 3

[0113] Thermochromic Dye D 2

[0114] Basic Brilliant Blue 0.5

[0115] Surfactant (BYK306) 0.5

[0116] Methyl Ethyl Ketone 200

[0117] 1-Methoxy-2-propanol 700

[0118] Example 4

[0119] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0120] Special thermosensitive resin L2 75

[0121] Crosslinker P 20

[0122] Diaryl iodonium hexafluorophosphate salt 3

[0123] Thermochromic Dye D 2

[0124] Basic Brilliant Blue 0.5

[0125] Surfactant (BYK306) 0.5

[0126] Methyl Ethyl Ketone 200

[0127] 1-Methoxy-2-propanol 700

[0128] Example 5

[0129] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0130] Special thermosensitive resin L2 70

[0131] Crosslinker P 25

[0132] Diaryl iodonium hexafluorophosphate salt 3

[0133] Thermochromic Dye D 2

[0134] Basic Brilliant Blue 0.5

[0135] Surfactant (BYK306) 0.5

[0136] Methyl Ethyl Ketone 200

[0137] 1-Methoxy-2-propanol 700

[0138] Example 6

[0139] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0140] Special thermosensitive resin L2 65

[0141] Crosslinker P 30

[0142] Diaryl iodonium hexafluorophosphate salt 3

[0143] Thermochromic Dye D 2

[0144] Basic Brilliant Blue 0.5

[0145] Surfactant (BYK306) 0.5

[0146] Methyl Ethyl Ketone 200

[0147] 1-Methoxy-2-propanol 700

[0148] Example 7

[0149] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0150] Special thermosensitive resin L3 60

[0151] Crosslinker P 30

[0152] Diaryl iodonium hexafluorophosphate salt 5

[0153] Thermochromic Dye D 5

[0154] Basic Brilliant Blue 0.5

[0155] Surfactant (BYK306) 0.5

[0156] Methyl Ethyl Ketone 200

[0157] 1-Methoxy-2-propanol 700

[0158] Example 8

[0159] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0160] Special thermosensitive resin L3 55

[0161] Crosslinker P 15

[0162] Diaryl iodonium hexafluorophosphate salt 15

[0163] Thermochromic Dye D 15

[0164] Basic Brilliant Blue 0.5

[0165] Surfactant (BYK306) 0.5

[0166] Methyl Ethyl Ketone 200

[0167] 1-Methoxy-2-propanol 700

[0168] Example 9

[0169] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0170] Special thermosensitive resin L3 50

[0171] Crosslinker P 30

[0172] Diaryl iodonium hexafluorophosphate salt 10

[0173] Thermochromic Dye D 10

[0174] Basic Brilliant Blue 0.5

[0175] Surfactant (BYK306) 0.5

[0176] Methyl Ethyl Ketone 200

[0177] 1-Methoxy-2-propanol 700

[0178] Example 10

[0179] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0180] Special thermosensitive resin L4 85

[0181] Crosslinker P 10

[0182] Diaryl iodonium hexafluorophosphate salt 3

[0183] Thermochromic Dye D 2

[0184] Basic Brilliant Blue 0.5

[0185] Surfactant (BYK306) 0.5

[0186] Methyl Ethyl Ketone 200

[0187] 1-Methoxy-2-propanol 700

[0188] Embodiment 11

[0189] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0190] Special thermosensitive resin L5 85

[0191] Crosslinker P 10

[0192] Diaryl iodonium hexafluorophosphate salt 3

[0193] Thermochromic Dye D 2

[0194] Basic Brilliant Blue 0.5

[0195] Surfactant (BYK306) 0.5

[0196] Methyl Ethyl Ketone 200

[0197] 1-Methoxy-2-propanol 700

[0198] Example 12

[0199] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0200] Special thermosensitive resin L6 85

[0201] Crosslinker P 10

[0202] Diaryl iodonium hexafluorophosphate salt 3

[0203] Thermochromic Dye D 2

[0204] Basic Brilliant Blue 0.5

[0205] Surfactant (BYK306) 0.5

[0206] Methyl Ethyl Ketone 200

[0207] 1-Methoxy-2-propanol 700

[0208] Example 13

[0209] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0210] Special thermosensitive resin L7 85

[0211] Crosslinker P 10

[0212] Diaryl iodonium hexafluorophosphate salt 3

[0213] Thermochromic Dye D 2

[0214] Basic Brilliant Blue 0.5

[0215] Surfactant (BYK306) 0.5

[0216] Methyl Ethyl Ketone 200

[0217] 1-Methoxy-2-propanol 700

[0218] Embodiment 14

[0219] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0220] Special thermosensitive resin L8 85

[0221] Crosslinker P 10

[0222] Diaryl iodonium hexafluorophosphate salt 3

[0223] Thermochromic Dye D 2

[0224] Basic Brilliant Blue 0.5

[0225] Surfactant (BYK306) 0.5

[0226] Methyl Ethyl Ketone 200

[0227] 1-Methoxy-2-propanol 700

[0228] Embodiment 15

[0229] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0230] Special thermosensitive resin L9 85

[0231] Crosslinker P 10

[0232] Diaryl iodonium hexafluorophosphate salt 3

[0233] Thermochromic Dye D 2

[0234] Basic Brilliant Blue 0.5

[0235] Surfactant (BYK306) 0.5

[0236] Methyl Ethyl Ketone 200

[0237] 1-Methoxy-2-propanol 700

[0238] Example 16

[0239] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0240] Special thermosensitive resin L10 85

[0241] Crosslinker P 10

[0242] Diaryl iodonium hexafluorophosphate salt 4

[0243] Thermochromic Dye D 1

[0244] Basic Brilliant Blue 0.5

[0245] Surfactant (BYK306) 0.5

[0246] Methyl Ethyl Ketone 200

[0247] 1-Methoxy-2-propanol 700

[0248] Embodiment 17

[0249] Use the same method as above to prepare the base and heat-sensitive layer, and the photosensitive liquid uses the following components:

[0250] Special thermosensitive resin L11 85

[0251] Crosslinker P 10

[0252] Diaryl iodonium hexafluorophosphate salt 1

[0253] Thermochromic Dye D 4

[0254] Basic Brilliant Blue 0.5

[0255] Surfactant (BYK306) 0.5

[0256] Methyl Ethyl Ketone 200

[0257] 1-Methoxy-2-propanol 700

[0258] Embodiment 18

[0259] The substrate and the heat-sensitive layer were prepared in the same manner as in Example 1, except that the average center line thickness of the substrate was set to 0.4 μm.

[0260] Embodiment 19

[0261] The same method as in Example 1 was used to prepare the substrate and the heat-sensitive layer, except that the average center line thickness of the substrate was set to 0.6 μm.

[0262] Embodiment 20

[0263] The plate base and heat-sensitive layer were prepared in the same manner as in Example 1, except that the dry coating weight of the photosensitive layer was 8 mg / dm 2 .

[0264] Embodiment 21

[0265] The plate base and heat-sensitive layer were prepared in the same manner as in Example 1, except that the dry coating weight of the photosensitive layer was 15 mg / dm 2 .

[0266] Comparative Examples 1-5

[0267] The substrate and the heat-sensitive layer were prepared in the same manner as in Example 1. The photosensitive solution used the following components:

[0268] Polymer A1-A5 70

[0269] Pentaerythritol triacrylate 15

[0270] Hydroxypropyl cellulose 10

[0271] Diaryl iodonium hexafluorophosphate salt 2.5

[0272] Thermosensitive dye ADS830 1

[0273] Nitrogen oxide free radical piperidinol 0.5

[0274] Basic Brilliant Blue 0.5

[0275] Surfactant (BYK306) 0.5

[0276] Methyl Ethyl Ketone 200

[0277] 1-Methoxy-2-propanol 700

[0278] That is, the above polymers A1-A5 are 70 parts respectively, and other raw materials and amounts are the same, and the corresponding photosensitive solutions of Comparative Examples 1-5 are obtained respectively.

[0279] Oxygen barrier coating: The following oxygen barrier solution was extrusion coated on the above-obtained heat-sensitive layer, and then dried at 110°C for 60 seconds. 2 The dry weight of the coating (each component is by weight).

[0280] Oxygen barrier layer formula (components by weight)

[0281] Polyvinyl alcohol PVA-205 (Japan Kuraray) 17

[0282] Polyvinylpyrrolidone PVPK30 (BASF, Germany) 3

[0283] Emulsifier OP-10 (Helm, Germany) 0.45

[0284] Deionized water 480

[0285] Comparative Examples 6-10

[0286] The substrate and the heat-sensitive layer were prepared in the same manner as in Example 1. The photosensitive solution used the following components:

[0287] Polymer K1-K5 70

[0288] Pentaerythritol triacrylate 25

[0289] Diaryl iodonium hexafluorophosphate salt 2.5

[0290] Thermosensitive dye ADS830 1

[0291] Nitrogen oxide free radical piperidinol 0.5

[0292] Basic Brilliant Blue 0.5

[0293] Surfactant (BYK306) 0.5

[0294] Methyl Ethyl Ketone 200

[0295] 1-Methoxy-2-propanol 700

[0296] That is, the above polymers K1-K5 are 70 parts respectively, and other raw materials and amounts are the same, and the corresponding photosensitive solutions of Comparative Examples 6-10 are obtained respectively.

[0297] Oxygen barrier coating: The oxygen barrier solution was extrusion coated on the above-obtained heat-sensitive layer, and then dried at 110° C. for 60 seconds to obtain a coating dry weight of 10 mg / dm2 (each component is by weight).

[0298] Oxygen barrier layer formula (components by weight)

[0299] Polyvinyl alcohol PVA-205 (Japan Kuraray) 17

[0300] Polyvinylpyrrolidone PVPK30 (BASF, Germany) 3

[0301] Emulsifier OP-10 (Helm, Germany) 0.45

[0302] Deionized water 480

[0303] Application detection:

[0304] 1. Dot reproduction: The above plates are exposed to 120mJ / cm2 energy on a Kodak Thermal CTP plate-making machine to test whether they can reproduce 1%-99% of the dots. 1%-99% is the best, 2%-99% is the second best, 3%-98% is the worst, and so on. The performance is shown in Table 1;

[0305] 2. Contrast △E1: The above plates are exposed at 120mJ / cm2 energy on a Kodak Thermal CTP plate-making machine, and the density difference between 100% solid exposure density and unexposed density is tested. The larger the contrast △E1, the higher the image is recognizable to the naked eye, and the crosshairs of the image after scanning and exposure are automatically recognizable by the computer system of the printing machine. Performance is shown in Table 1;

[0306] 3. Color difference △E2: The above plates were exposed at 160mJ / cm2 and 80mJ / cm2 on a Kodak Thermal CTP plate-making machine, and the density difference of the two different exposures of 100% solid black ink was tested. The smaller the color difference △E2, the greater the exposure latitude of the plate, and the better the color uniformity of the prints exposed by different models of exposure machines. Performance is shown in Table 1;

[0307] 4. Water development time: The above plates were exposed to 120mJ / cm2 energy on a Kodak Thermal CTP platemaker, and the time (in seconds) required to remove the unexposed layer by water development at 25°C was tested. The shorter the water development time, the better the low chemical development of the plate. Performance is shown in Table 1;

[0308] 5. Number of paper passes: The above-mentioned plates are exposed to 120mJ / cm2 energy on a Kodak Thermal CTP plate-making machine, and directly put on a printing press. The plates are developed under the action of the fountain solution, and the paper is taken away from the unexposed layer. The number of papers consumed before the printed product is normal is tested (unit: sheets). The fewer the number of paper passes, the better the on-machine development performance of the plates. The performance is shown in Table 1;

[0309] 6. Printing life: The above plates are exposed to 120mJ / cm2 energy on a Kodak Thermal CTP plate-making machine, and printed on a Beiren four-color rotary printing machine to test the number of normal prints that can be printed (unit: 10,000 prints). The higher the number of normal prints, the better the plate quality. Performance is shown in Table 1;

[0310] The detection and application results in Table 1 show that, compared with other environmentally friendly thermal plates, the environmentally friendly thermal plate designed by the present invention improves the sensitivity of the plate material and improves the dot quality of the plate material through the dual imaging mechanism of cationic polymerization and urethanization reaction; introduces a thermosetting high wear-resistant urethanide bond network cross-linking structure through a cross-linking agent to improve the printing durability of the plate material; improves the uniformity of color restoration of the image layer by increasing the exposure latitude; selects a special structure of thermochromic dye to improve the plate making contrast of the plate material, and solves the problem of automatic plate recognition by computers; the plate material has a hydroxyethylated acrylamide hydrophilic unit, can realize water development or on-machine development, and is a green and environmentally friendly thermal plate.

[0311] Table 1 Plate application performance table

[0312]

[0313] The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. It should be pointed out that for those skilled in the art and any technician familiar with the technical field, without departing from the overall concept of the present invention, the technical solution and the inventive concept of the present invention are equivalently replaced or changed, and several changes and improvements are made, which should also be regarded as the protection scope of the present invention.

Claims

1. A heat-sensitive resin, characterized in that: The heat-sensitive resin is a ternary free radical copolymer of monomer a: methacrylamide, monomer b: hydroxyethyl acrylamide and monomer c: 3,4-epoxycyclohexyl methacrylate, wherein the weight proportion of the methacrylamide unit in the copolymer is 40-80% (weight percentage), the weight proportion of the hydroxyethyl acrylamide unit in the copolymer is 10-30% (weight percentage), and the weight proportion of the 3,4-epoxycyclohexyl methacrylate unit in the copolymer is 10-30% (weight percentage).

2. The heat-sensitive resin according to claim 1, characterized in that: The weight average molecular weight of the heat-sensitive resin is 4000-150000, and the glass transition temperature is 110-130°C.

3. The method for preparing a heat-sensitive resin according to claim 1 or 2, characterized in that: The heat-sensitive resin is prepared by solution or emulsion copolymerization.

4. An environmentally friendly thermal plate, characterized in that: The thermal plate comprises a hydrophilic carrier and a thermal layer, wherein the thermal layer contains the thermal resin, crosslinking agent, thermal initiator and thermal color-changing dye according to claim 1 or 2; by weight percentage, the thermal resin accounts for 50-90% of the total solid amount of the thermal layer composition, the crosslinking agent accounts for 5-30% of the total solid amount of the thermal layer composition, the thermal initiator accounts for 1-15% of the total solid amount of the thermal layer composition, and the thermal color-changing dye accounts for 1-15% of the total solid amount of the thermal layer composition.

5. The environmentally friendly thermal plate according to claim 4, characterized in that: The crosslinking agent has the following structure: 。 6. The environmentally friendly thermal plate according to claim 4, characterized in that: The thermosensitive layer comprises, by weight percentage, 60-80% of the total solid content of the thermosensitive layer composition of the thermosensitive resin, 10-20% of the total solid content of the thermosensitive layer composition of the crosslinking agent, 1-10% of the total solid content of the thermosensitive layer composition of the thermal initiator, and 1-10% of the total solid content of the thermosensitive layer composition of the thermosensitive dye.

7. The environmentally friendly thermal plate according to claim 4, characterized in that: The thermal initiator is selected from one or more of iodonium salts and sulfonium salts, and the decomposition temperature is 150-220°C; the thermochromic dye is a thermochromic azamethine dye; the hydrophilic carrier is an aluminum plate substrate that has been electrolytically roughened, anodized and sealed, and the average centerline roughness is 0.4-0.6 μm.

8. The environmentally friendly thermal plate according to claim 7, characterized in that: Thermochromic dye is a thermochromic azamethine dye with an absorption peak at 730-880nm.

9. The method for preparing an environmentally friendly thermal plate according to claim 4, characterized in that: The specific steps are as follows: (1) treating the aluminum substrate with a hydrophilic carrier; (2) coating the treated aluminum substrate with a heat-sensitive layer, wherein the dry weight of the heat-sensitive layer is 8-15 mg / dm 2 .

10. The method for applying the environmentally friendly thermal plate according to claim 4, characterized in that: After the thermal plate is scanned and exposed by a thermal CTP plate-making machine, it is washed and developed with water or directly mounted on a printing press and developed and printed with a printing press fountain solution.

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