CN113912772A

CN113912772A - Thermosensitive resin, environment-friendly thermosensitive plate and preparation method thereof

Info

Publication number: CN113912772A
Application number: CN202111303699.5A
Authority: CN
Inventors: 宋小伟; 齐海潮; 张伟; 张攀; 杨帅; 刘晓蕾
Original assignee: Lucky Huaguang Graphics Co Ltd
Current assignee: Lucky Huaguang Graphics Co Ltd
Priority date: 2021-11-05
Filing date: 2021-11-05
Publication date: 2022-01-11

Abstract

The invention provides a thermosensitive resin, an environment-friendly thermosensitive plate and a preparation method thereof, wherein the thermosensitive resin is an important binder, namely functional film-forming resin, in a thermosensitive coating for forming a thermosensitive layer, and can improve the water or fountain solution developing capability of a plate material and the capability of resisting chemical etching in printing ink, realize that an image layer has a thermosetting urethane bond network structure, increase the wear resistance of the plate material coating and improve the printing resistance of the plate material. The environment-friendly thermosensitive plate has hydrophilicity, can realize water development or fountain solution development, is an environment-friendly thermosensitive plate, and improves the sensitivity of the thermosensitive plate and the dot reduction precision of a plate material through the thermosensitive resin, the cross-linking agent and the thermosensitive color-changing dye with special structures; the printing resistance of the plate is improved, and the problem of color reduction uniformity of an image layer is improved by improving the exposure latitude; the developing property and the printing resistance of the printing plate are improved; the plate making contrast of the plate material is improved, and the problem of automatic plate material identification by a computer is solved.

Description

Thermosensitive resin, environment-friendly thermosensitive plate and preparation method thereof

Technical Field

The invention belongs to the technical field of lithographic printing, and particularly relates to a thermosensitive resin, an environment-friendly thermosensitive plate and a preparation method thereof.

Background

For a long time, the printing industry in China, particularly the packaging printing industry, is developed in a rough manner under the conditions of high consumption and high pollution. However, with the vulnerability of the living ecosystem of human beings, the deterioration of the environment, the high shortage of resources, and the burden of both the resource stock and the environment load. The printing and post-printing processing technologies have the problem of environmental pollution. For example, the developing solution used for plate making before printing contains toxic chemical components, and common printing ink, car washing water and the like used for printing contain heavy metal elements such as lead, chromium, mercury and the like, which cause certain damage to human health. Therefore, it is urgently required to strongly carry out green printing.

The green printing appeared in western countries represented by japan, usa, germany, etc. in the late 80 th 20 th century, and through the development of more than twenty years, the development has progressed from the concept discussion stage to the practical application stage, and the development has been advanced and matured greatly in the aspects of concept, technical standards, equipment and process, raw and auxiliary materials, and software application. In developed countries in europe and america, green printing is an embodiment of the technological development level, and is also an effective means for replacing the traditional printing mode which causes environmental pollution and high energy consumption.

The green printing is a printing mode which adopts environment-friendly materials and processes, generates little pollution in the printing process, saves resources and energy, is easy to recycle and recycle after being discarded, can be naturally degraded and has little influence on the ecological environment. The green printing requirements are coordinated with the environment, including the use of environmentally friendly printing materials, clean printing production processes, the safety of the printed matter to users, and the recycling and reutilization of the printed matter. Namely, the whole life cycle of the printed matter, such as raw material selection, production, use, recovery and the like, is in accordance with the environmental protection requirement.

Currently, green printing is leading the development of printing industry with its strong influence. The prepress plate making has entered the CTP era, so the environment-friendly treatment-free CTP plate material becomes a hot spot of interest in the industry. The processing-free CTP plate material is a processing-free plate material in a real sense, which can be printed on a computer without any subsequent processing procedure after the plate material is exposed and imaged on direct plate-making equipment, and certainly does not need chemical development and washing processing. In a narrow sense, the plate material does not need chemical development after exposure and imaging on a direct plate-making machine, but there are separate non-chemical treatment processes, such as removing ablation scraps of the plate material, coating protective glue, and the like.

Development of green and environment-friendly printing consumables, particularly green and environment-friendly printing plates, is the focus of development of green printing.

The heat-sensitive CTP plate has been widely used, and the development of the first generation of heat-sensitive negative plate to the second generation of mature heat-sensitive positive plate which is largely used, and the development of the third generation of heat-sensitive plate material technology aims at no treatment. The development of the current printing plate materials is developed towards the direction of green and environmental protection, and CTP (computer to plate) plates free of (low) chemical treatment are successively proposed by various famous printing plate material manufacturers in the world.

Classifying treatment-free CTP plates: at present, the treatment-free CTP plates in the market are numerous, and according to the characteristics of the plates, the treatment-free CTP plates can be divided into the following two categories:

(1) the CTP plate is completely free from treatment. The CTP plate material is a CTP plate material which can be directly printed on a machine after being imaged on plate making equipment. According to different imaging modes, the imaging method can be mainly divided into an ablation type treatment-free CTP plate and a thermotropic polarity treatment-free CTP plate.

(2) An environment-friendly developing type treatment-free CTP plate. The CTP plate is exposed and imaged on a plate making machine, and is developed before being printed on the machine, and the process does not need chemical developing solution, and the CTP plate can be developed by adopting clean water to clean or performing gluing protection on the plate; or the CTP plate material is exposed and imaged on a plate making machine, and then is developed on a printing machine by utilizing the wetting effect of the fountain solution, and the non-image-text part of the medicine film is removed.

The development of green and environment-friendly treatment-free CTP plates has many technical routes, which can be divided into a thermal ablation technology, a phase change technology and a hot melting technology. The thermal ablation technology means that infrared laser energy ablates the oleophilic coating to expose the hydrophilic surface of the aluminum plate to form a hydrophilic area; the phase change technology means that the laser energy enables the polymer to generate hydrophilic-lipophilic conversion, and ink and water separation is realized; the hot melt technique is a technique in which laser energy melts thermoplastic polymer particles dispersed in a crosslinked hydrophilic layer from hydrophilic to hydrophobic and oleophilic. .

Developing a chemical treatment-free CTP plate technology: EP0980754 describes a technique for decarboxylation to achieve hydrophilic-hydrophobic transitions, but with poor print durability. WO94/23954 describes hot melt micro-gluing techniques, but is prone to soiling; US4004924 describes a mixture of thermoplastic hydrophobic particles and a hydrophilic binder, which is also not print-resistant; EP 2006-5-2406114475.4 describes hot-melt thermoplastic granules which are liable to contaminate the fountain solution; US 2005-8-311/196, 124 describes a one-dimensional linear structure hydrophilic adhesive with low print durability; US 2006-7-2711/494, 235 describes a printing plate precursor containing hydrophilic groups and esterified allyl groups, but the ester groups are not resistant to ink attack.

Currently, environment-friendly thermosensitive plates are classified into two types, a double-layer plate and a single-layer plate.

The double-layer environment-friendly thermosensitive plate is generally a double-bond free radical imaging mechanism, and in order to reduce the stopping effect of oxygen on free radical reaction, an oxygen-blocking protective layer is arranged on a plate material.

The single-layer environment-friendly thermal plate is generally a non-oxygen polymerization inhibition imaging mechanism, and the plate does not need to be provided with an oxygen inhibition protective layer.

At present, the problems of the environment-friendly thermosensitive plate are that: 1. the problem of the dot reduction precision; 2. problems with low chemical development or on-press developability; 3. color reduction uniformity problem; 4. the problem of pressrun, and the problem of plate making contrast.

The problem of the dot reduction precision is mainly reflected in the accurate reduction of image dots; the problem of low chemical development or on-press development capability mainly reflects whether the thermosensitive plate can be developed by water flushing or directly mounted on a printing machine and developed and printed by fountain solution of the printing machine after being scanned and exposed by the thermosensitive CTP plate making machine; the problem of color reduction uniformity is mainly reflected in that the printing plate absorbs ink quantities of different color inks, and the difference of the ink quantities is directly expressed as the color difference of a printing product; the plate making contrast problem reflects whether the image cross line can be automatically identified by a computer system of a printing machine after the thermosensitive plate is scanned and exposed by a thermosensitive CTP plate making machine.

Disclosure of Invention

In order to solve the problems, the invention provides a thermosensitive resin, an environment-friendly thermosensitive plate and a preparation method thereof, wherein the thermosensitive resin is an important binder, namely functional film-forming resin, in a thermosensitive coating for forming a thermosensitive layer, and can improve the developing capability of a plate material in water or fountain solution and the capability of resisting chemical etching in ink, realize that an image layer has a thermosetting urethane bond network structure, increase the wear resistance of the plate material coating and improve the printing resistance of the plate material. The environment-friendly thermosensitive plate has hydrophilicity, can realize water development or fountain solution development, is an environment-friendly thermosensitive plate, and improves the sensitivity of the thermosensitive plate and the dot reduction precision of a plate material through the thermosensitive resin, the cross-linking agent and the thermosensitive color-changing dye with special structures; the printing resistance of the plate is improved, and the problem of color reduction uniformity of an image layer is improved by improving the exposure latitude; the developing property and the printing resistance of the printing plate are improved; the plate making contrast of the plate material is improved, and the problem of automatic plate material identification by a computer is solved.

The object of the invention is achieved in the following way: the thermosensitive resin is monomer a: methacrylamide, monomer b: hydroxyethyl acrylamide and monomer c: the ternary free radical copolymer of 3, 4-epoxy cyclohexyl methyl acrylate has methacrylamide unit in 40-80 wt%, hydroxyethyl acrylamide unit in 10-30 wt% and 3, 4-epoxy cyclohexyl methyl acrylate unit in 10-30 wt%.

The heat-sensitive plate is designed by considering the heat-sensitive coating of the plate firstly, and the heat-sensitive coating needs an important binder, namely functional film-forming resin, and the resin can form a film after ensuring that the coating liquid of the heat-sensitive coating is dried, so that the heat-sensitive coating is attached to a hydrophilic carrier. The binder may be in the form of a solution or an emulsion. Meanwhile, the functional film-forming resin contains functional groups and plays a special function role, and the thermosensitive resin is the adhesive.

The thermosensitive resin contains a hydrophilic structural unit, namely a methacrylamide unit, and after infrared laser scanning imaging, the molecular weight of a thermosensitive layer is rapidly increased, so that the coating is firmer, and the coating after laser thermal exposure is difficult to remove by water and ink; the residual coating of the unexposed blank part is easily removed by water due to the existence of amide groups, and the exposed blank part is a hydrophilic aluminum plate base, so that the environmental protection purpose of no pollutant discharge in the plate making process is realized. The methacrylamide unit content is between 40 and 80% by weight in the copolymer.

The thermosensitive resin contains a hydroxyethyl acrylamide structural unit, the hydroxyethyl acrylamide has good hydrophilicity and oil resistance, the water or fountain solution developing capability of the plate and the capability of resisting chemical corrosion in printing ink can be improved, and meanwhile, hydroxyl energy in the hydroxyethyl acrylamide and isocyanate groups thermally released by a cross-linking agent are subjected to a cross-linking reaction, so that an image layer has a thermosetting urethane bond network structure, and the pressrun of the thermosensitive resin is higher than that of a traditional linear polymerization thermoplastic plate. The content of the hydroxyethyl acrylamide copolymerized unit b in the copolymer is 10-30 wt%.

The special thermosensitive resin designed by the invention contains epoxy bonds on cyclohexyl, has high-efficiency cationic crosslinking capability, laser heat energy is transferred to a thermal initiator through a thermosensitive color-changing dye, and the thermal initiator is heterolytic to generate cations, so that the epoxy bonds on the cyclohexyl in the special thermosensitive resin and the epoxy bonds in a crosslinking agent are crosslinked and polymerized. The epoxy bond on the cyclohexyl contained in the thermosensitive resin has ultrahigh cationic crosslinking capability, and the cyclohexyl has certain rigidity, so that the wear resistance of a plate coating can be improved, and the printing resistance of the plate can be improved. The content of the copolymerized unit c containing an epoxy bond in a cyclohexyl group in the multipolymer is 10 to 30% by weight.

The heat-sensitive resin is synthesized by adopting a solution or emulsion copolymerization method, and the copolymerization reaction can be random copolymerization or block copolymerization, preferably random copolymerization. The polymerization initiator includes peroxides such as di-t-butyl peroxide, benzoyl peroxide, persulfates such as potassium persulfate, amine persulfate, azo compounds such as azobisisobutyronitrile, etc., and the copolymerization is preferably a solution polymerization.

As the reaction solvent, there can be mentioned water, methanol, ethanol, N-propanol, isopropanol, butanol, acetone, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, tetrahydrofuran, 1, 4-dioxane, N-dimethylformamide, dimethylacetamide acetone, 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, ethyl lactate and the like, or a mixture thereof. The copolymerization reaction temperature is preferably 40 to 100 ℃ and most preferably 60 to 90 ℃.

The weight average molecular weight of the thermal sensitive resin is 4000-150000, and the glass transition temperature is 110-130 ℃.

The green environment-friendly thermosensitive plate comprises a hydrophilic carrier and a thermosensitive layer, wherein the thermosensitive layer contains the thermosensitive resin, a cross-linking agent, a thermal initiator and a thermosensitive color-changing dye; the heat-sensitive resin accounts for 50-90%, preferably 60-80% of the total solid content of the heat-sensitive layer.

The environment-friendly thermosensitive plate improves the performance of the plate material by adding a special cross-linking agent, and has the following structure (code number; cross-linking agent P):

the environment-friendly thermosensitive plate improves the imaging capability of the plate material by adding the special cross-linking agent, and the plate material has double imaging mechanisms of cationic polymerization and urethane reaction. The laser thermal energy transfers energy to a thermal initiator through a thermal dye, and cations generated by heterolysis of the thermal initiator enable epoxy bonds in a cross-linking agent and epoxy bonds on cyclohexyl in special thermal-sensitive resin to generate cation network cross-linking, so that cation network thermal-sensitive imaging is realized; meanwhile, the plate material has the capability of aminoesterification reticular thermal imaging, the caprolactam group at the tail end is removed by the cross-linking agent under the action of laser heat, and the active isocyanate group is released and can perform urethane reaction with the hydroxyl group on the special thermal sensitive resin, so that a thermosetting urethane-bond reticular structure image is formed, and the sensitivity and the printing resistance of the plate material are improved. The cross-linking agent accounts for 5-30%, preferably 10-20% of the total solid content of the heat-sensitive layer composition.

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

The plate material has cationic polymerization imaging capability, so the thermal initiator is also called cationic photopolymerization initiator, and the thermal initiator is selected from onium salts, such as sulfonium salt, iodonium salt, etc. Suitable onium salts include sulfonium salts, maple oxide salts, sulfoxonium salts, diazonium salts, and halonium salts such as iodonium anchor salts, and the like. Specific examples of suitable onium salts are: diphenyliodonium chloride, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, [4- [ (2-hydroxytetradecyl-oxy ] -phenyl ] phenyliodonium hexafluoroantimonate, triphenylsulfonium iodonium tetrafluoroborate, triphenylsulfonium iodonium octylsulfate, 2-methoxy-4-aminophenyldiazonium hexafluorophosphate, phenoxyphenyldiazonium hexafluoroantimonate, and the like, the cationic photopolymerization initiator according to the present invention is one or more selected from the group consisting of iodonium salts and sulfonium salts, and the thermal decomposition temperature thereof is 200 ℃ at 150. the cationic photopolymerization initiator preferably accounts for 1 to 15% by dry weight of the coating film (i.e., the total amount of solids of the heat-sensitive layer composition) in the heat-sensitive layer, and more preferably 1 to 10%.

The components of the thermosensitive layer of the thermosensitive plate of the present invention are detailed below: a thermochromic dye.

The component thermosensitive color-changing dye in the thermosensitive plate composition has the functions of infrared dye and laser color change, and mainly plays roles in energy transfer and color change. The heat of the infrared laser transmits the laser energy to the thermal initiator through the thermosensitive color-changing dye, and the thermal initiator generates cations to initiate the polymerization of epoxy groups in the system, so that the thermosensitive imaging is realized. The laser energy is converted into heat energy through the thermosensitive dye, the caprolactam group at the tail end of the cross-linking agent is removed, active isocyanate group is released, and the active isocyanate group can perform urethane reaction with the hydroxyl group on the special thermosensitive resin, so that a thermosetting urethane bond network structure image is formed. Meanwhile, the thermochromic dye has a laser color changing function, can perform closed-loop reaction under the action of laser heat, so that the color is changed, the color change is irreversible, the contrast presentation of a non-development type plate material is realized, the image defect of a printing plate is favorably detected by the naked eye plate correction of a printing operator, and meanwhile, the automatic intelligent plate installation can be realized through the automatic positioning recognition of a modern highly intelligent printing machine. The thermochromic dye of the present invention may be a thermochromic azamethine dye. The thermochromic azamethine dyes having an absorption peak at 730-880nm can be selected, preferably from azamethine dyes of the following structure (code: thermochromic dye D):

the thermosensitive color-changing dye accounts for 1-15% of the dry weight of the coating film in the thermosensitive layer, preferably 5-10%.

Finally, the hydrophilic support of the thermal plate of the present invention is described in detail.

The heat-sensitive layer composition of the present invention is applied to a heat-sensitive plate hydrophilic support including a metal plate base such as a copper plate base, an aluminum plate base, etc. The hydrophilic carrier selected by the invention is an aluminum plate base which is subjected to electrolytic roughening, anodic oxidation and hole sealing treatment, the average roughness of the central line is 0.3-0.6um, and the hydrophilic carrier is prepared by electrolytic roughening. The aluminum plate base is more than 99 percent of aluminum, 0.1 to 0.5 percent of iron, 0.03 to 0.3 percent of silicon, 0.003 to 0.03 percent of copper and 0.01 to 0.l percent of titanium. The electrolytic roughening electrolyte may be an aqueous solution of an acid, base or salt. Firstly, the aluminum plate is put into 1% -30% aqueous solution of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate and the like, and is chemically corroded at the temperature of 20-80 ℃ for 5-250 seconds. Then neutralizing in 10% -30% nitric acid or sulfuric acid at 20-70 deg.C to remove gray matter. At 10-60 deg.C, using rectangular wave, table wave or sine wave of positive and negative interaction change at 5-100A/dm²The current density of (2) is electrolytic treatment in an electrolyte of nitric acid or hydrochloric acid for 10 to 300 seconds. Then, anodic oxidation treatment is performed. The anodic oxidation is usually carried out by sulfuric acid process using sulfuric acid having a concentration of 5-30% and a current density of 1-15A/dm²The oxidation temperature is 20-60 deg.C, and the oxidation time is 5-250 s, so as to form 1-10g/m²And finally, sealing the hole. The sealing treatment can be carried out by various methods, preferably by sealing 50 to 80% by volume of the micropores of the oxide film, and finally coating polyvinyl phosphonic acid to a thickness of 3mg/m on the aluminum plate treated as above²。

The heat-sensitive layer composition of the present invention may be produced by adding other necessary additives such as a solvent, a room temperature thermal polymerization inhibitor, a surfactant, and the like. The solvent is mainly used for preparing the photosensitive liquid of the thermosensitive coating, and comprises the following components: alcohols, ketones, esters, ethers, amides, aromatic solvents, ethylene dichloride, tetrahydrofuran, and the like, the solvents may be used in pure form or in the form of a mixture; the normal temperature thermal polymerization inhibitor is used for preventing the sheet material from polymerizing at normal temperature and improving the normal temperature stability of the plate material. The thermal polymerization inhibitor includes: hydroquinone, nitroxide radical piperidinol, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4 '-thiobis- (3-methyl-6-t-butylphenol), 2' -methylenebis (4-methyl-16-t-butylphenol), and the primary cerium salt of N-nitrosophenylhydroxylamine, and the like; the addition of the layer coloring agent is to increase the image density of the heat-sensitive plate after platemaking, so that the heat-sensitive plate after platemaking can be conveniently subjected to visual inspection or the performance of the plate material can be conveniently measured by an image analysis measuring device, and the method comprises the following steps: methyl violet, ethyl violet, crystal violet, victoria blue, oil green, oil blue, oil yellow, rhodamine B, methyl violet, malachite green, methylene blue, triazines, and the like; the coating layer is also added with surfactant, such as nonionic surfactant, amphoteric surfactant, silicon-containing surfactant, fluorine-containing surfactant, etc., such as betaine, glyceryl stearate, sorbitan, polysiloxane, and polyfluoroalkyl ether.

The heat sensitive layer compositions of the present invention are typically coated using techniques known in the art (e.g., knife coating, bar coating, roll coating, press coating, etc.).

Compared with the prior art, the thermosensitive resin provided by the application is an important binder in the thermosensitive coating for forming the thermosensitive layer, namely, the functional film-forming resin, and 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 the thermosensitive layer. The binder may be in the form of a solution or an emulsion. Meanwhile, the functional film forming resin contains hydrophilic units of methacrylamide and hydroxyethylated acrylamide, can realize water development or on-press development, and is a green and environment-friendly thermosensitive plate. In addition, the developing capability of the plate material in water or fountain solution and the capability of resisting chemical erosion in printing ink can be improved, the image layer has a thermosetting urethane bond net structure, the printing resistance is higher than that of the traditional linear polymerization thermoplastic plate material, the wear resistance of the plate material coating can be improved, and the printing resistance of the plate material is improved.

According to the invention, the thermosensitive resin, the cross-linking agent and the thermosensitive color-changing dye with special structures are adopted, and the sensitivity of the thermosensitive plate is improved and the dot reduction precision of the plate material is improved through a double imaging mechanism of cationic polymerization and urethane reaction; the thermosetting high-wear-resistance urethane bond net-shaped crosslinking structure is introduced through the crosslinking agent, so that the crosslinking density of the image layer is improved, the printing resistance of the plate is improved, and the color reduction uniformity of the image layer is improved by improving the exposure latitude; the development performance and the printing resistance of the plate are improved by introducing amide groups; the thermosensitive color-changing dye with a special structure is adopted to improve the plate making contrast of the plate material, and the problem of automatic plate material identification by a computer is solved; meanwhile, the plate material has hydrophilicity, can realize water development or fountain solution development, and is a green and environment-friendly thermosensitive plate.

Detailed Description

The present invention is described in detail below with reference to specific embodiments, it should be noted that the embodiments are only used for further illustration of the present invention, and should not be construed as limiting the scope of the present invention, and those skilled in the art can make modifications and adaptations of the present invention based on the above-mentioned disclosure.

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

Raw materials are available from the following companies: methacrylamide, hydroxyethyl acrylamide: shanghai Bailingwei science and technology; 3, 4-epoxycyclohexyl methacrylate CMA: mitsubishi yang chemical japan; dimethylacetamide DMAC: landification, azobisisobutyronitrile AIBN: tianjin Fuchen chemical reagent; benzoyl peroxide BPO: new Laiwukang reagent.

A first part: synthesis examples of specific Heat-sensitive resins (code number L) L1-L11

Example 1 (Special Heat-sensitive resin L1)

300g of dimethylacetamide, 80g (80 wt%) of methacrylamide, 10g (10 wt%) of hydroxyethyl acrylamide, 10g (10 wt%) of 3, 4-epoxycyclohexyl methacrylate and 1g of azobisisobutyronitrile are added into a 500 ml four-neck flask with a temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection device, uniformly stirred, reacted at 70 ℃ for 8 hours, and cooled to finish the reaction, and the reaction stock solution can be directly used.

Example 2 (Special Heat-sensitive resin L2)

300g of dimethylacetamide, 70g (70 wt%) of methacrylamide, 20g (20 wt%) of hydroxyethyl acrylamide, 10g (10 wt%) of 3, 4-epoxycyclohexyl methacrylate and 1g of azobisisobutyronitrile are added into a 500 ml four-neck flask with a temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection device, uniformly stirred, reacted at 70 ℃ for 8 hours, and cooled to finish the reaction, and the reaction stock solution can be directly used.

Example 3 (Special Heat-sensitive resin L3)

300g of dimethylacetamide, 70g (70 wt%) of methacrylamide, 10g (10 wt%) of hydroxyethyl acrylamide, 20g (20 wt%) of 3, 4-epoxycyclohexyl methacrylate and 1g of azobisisobutyronitrile are added into a 500 ml four-neck flask with a temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection device, uniformly stirred, reacted at 70 ℃ for 8 hours, and cooled to finish the reaction, and the reaction stock solution can be directly used.

Example 4 (Special Heat-sensitive resin L4)

300g of dimethylacetamide, 70g (70 wt%) of methacrylamide, 15g (15 wt%) of hydroxyethyl acrylamide, 15g (15 wt%) of 3, 4-epoxycyclohexyl methacrylate and 1g of azobisisobutyronitrile are added into a 500 ml four-neck flask with a temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection device, uniformly stirred, reacted at 70 ℃ for 8 hours, and cooled to finish the reaction, and the reaction stock solution can be directly used.

Example 5 (Special Heat-sensitive resin L5)

300g of dimethylacetamide, 60g (60 wt%) of methacrylamide, 30g (30 wt%) of hydroxyethyl acrylamide, 10g (10 wt%) of 3, 4-epoxycyclohexyl methacrylate and 1g of azobisisobutyronitrile are added into a 500 ml four-neck flask with a temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection device, uniformly stirred, reacted at 70 ℃ for 8 hours, and cooled to finish the reaction, and the reaction stock solution can be directly used.

Example 6 (Special Heat-sensitive resin L6)

300g of dimethylacetamide, 60g (60 wt%) of methacrylamide, 10g (10 wt%) of hydroxyethyl acrylamide, 30g (30 wt%) of 3, 4-epoxycyclohexyl methacrylate and 1g of azobisisobutyronitrile are added into a 500 ml four-neck flask with a temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection device, uniformly stirred, reacted at 70 ℃ for 8 hours, and cooled to finish the reaction, and the reaction stock solution can be directly used.

Example 7 (Special Heat-sensitive resin L7)

300g of dimethylacetamide, 60g (60 wt%) of methacrylamide, 20g (20 wt%) of hydroxyethyl acrylamide, 20g (20 wt%) of 3, 4-epoxycyclohexyl methacrylate and 1g of azobisisobutyronitrile are added into a 500 ml four-neck flask with a temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection device, the mixture is uniformly stirred and reacts at 70 ℃ for 8 hours, and the reaction is finished after cooling, so that the reaction stock solution can be directly used.

Example 8 (Special Heat-sensitive resin L8)

300g of dimethylacetamide, 50g (50 wt%) of methacrylamide, 20g (20 wt%) of hydroxyethyl acrylamide, 30g (30 wt%) of 3, 4-epoxycyclohexyl methacrylate and 1g of azobisisobutyronitrile are added into a 500 ml four-neck flask with a temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection device, the mixture is uniformly stirred and reacts at 70 ℃ for 8 hours, and the reaction is finished after cooling, so that the reaction stock solution can be directly used.

Example 9 (Special Heat-sensitive resin L9)

300g of dimethylacetamide, 50g (50 wt%) of methacrylamide, 30g (30 wt%) of hydroxyethyl acrylamide, 20g (20 wt%) of 3, 4-epoxycyclohexyl methacrylate and 1g of azobisisobutyronitrile are added into a 500 ml four-neck flask with a temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection device, the mixture is uniformly stirred and reacts at 70 ℃ for 8 hours, and the reaction is finished after cooling, so that the reaction stock solution can be directly used.

Example 10 (Special Heat-sensitive resin L10)

300g of dimethylacetamide, 50g (50 wt%) of methacrylamide, 25g (25 wt%) of hydroxyethyl acrylamide, 25g (25 wt%) of 3, 4-epoxycyclohexyl methacrylate and 1g of azobisisobutyronitrile are added into a 500 ml four-neck flask with a temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection device, uniformly stirred, reacted at 70 ℃ for 8 hours, and cooled to finish the reaction, and the reaction stock solution can be directly used.

Example 11 (Special Heat-sensitive resin L11)

300g of dimethylacetamide, 40g (40 wt%) of methacrylamide, 30g (30 wt%) of hydroxyethyl acrylamide, 30g (30 wt%) of 3, 4-epoxycyclohexyl methacrylate and 1g of azobisisobutyronitrile are added into a 500 ml four-neck flask with a temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection device, uniformly stirred, reacted at 70 ℃ for 8 hours, and cooled to finish the reaction, and the reaction stock solution can be directly used.

A second part: synthesis of the crosslinking agent P

Raw materials are available from the following companies: dicyclohexylmethane diisocyanate: german Bayer chemistry; 3-ethyl-3-oxetanemethanol: southwest xinnaxi new materials ltd; epsilon-caprolactam: shanghai Bailingwei science and technology; dibutyltin dilaurate: tianjin chemical reagent II; dimethyl acetamide: landification in Lanzhou province.

262.3g dicyclohexylmethane diisocyanate, 3g dibutyltin dilaurate and 491.7g dimethylacetamide are added into a 1000 ml four-neck flask with a temperature control heating, mechanical stirring, condensation reflux and drying tube, 116.2g 3-ethyl-3-oxetanylcarbinol is added dropwise when the temperature is increased to 50 ℃, the dropwise addition time is 30 minutes, the reaction is carried out for 1 hour, 113.2g epsilon-caprolactam is added, the reaction is carried out for 20 minutes, the reaction is carried out for 48 hours in ice-water bath until the peak of 2275 active isocyanate groups disappears through infrared spectrum detection, a dimethylformamide solution of a compound P with the solid content of 50% is obtained, and the solution can be directly used according to the solid content.

Comparative examples 1-5 (Synthesis of similar Ackero polymers A1-A5):

according to the introduction of Ekerhair patent EP 2006-5-2406114475.4, an Ekerhair-like polymer was synthesized by solution polymerization, but the polymer did not contain hydrophilic groups and the polymer structure:

a1: 400g of methyl ethyl ketone and 5g of sodium dodecyl sulfate are added into a 1000 ml four-neck flask with a temperature-controlled heating device, a mechanical stirring device, a condensation reflux device and a nitrogen protection device, 80g (80 wt%) of ST (styrene), 20g (20 wt%) of AN (acrylonitrile) and 0.7g of AIBN (azobisisobutyronitrile) are dropwise added at 80 ℃, the dropwise adding time is 0.5 hour, 0.3g of AIBN (azobisisobutyronitrile) is supplemented after 7.5 hours of reaction, and the reaction is continued for 12 hours and then is finished.

Changing the feeding proportion to synthesize the similar Ikefa polymer:

A2(ST:60,AN:40), A3(ST:50,AN:50) , A4(ST:40,AN:60),A5(ST:20,AN:80) 。

comparative examples 6-10 (Synthesis of similar kodak polymers K1-K5):

according to Kodak patent US 2005-8-311/196, an acrylic polymer is synthesized by solution polymerization, the polymer contains hydrophilic groups but no epoxy groups, the polymer structure:

k1: 400g of methyl ethyl ketone was added to a 1000 ml four-neck flask equipped with a temperature-controlled heating device, mechanical stirring device, reflux condenser and nitrogen blanket, 80g (80 wt%) of ST (styrene), 10g (10 wt%) of AN (acrylonitrile), 10g (0.7g (10 wt%) of PEGMA45 (polyethoxymethylacrylate, degree of polymerization N =45) and AIBN (azobisisobutyronitrile) were added dropwise at 80 ℃ for 0.5 hour, and after 7.5 hours of further reaction, 0.3g of AIBN (azobisisobutyronitrile) was added, and the reaction was continued for 12 hours and ended.

And (3) synthesizing a kodak-like polymer by changing the feeding ratio and the reaction concentration:

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)

the structural thermochromic dye D described above is commercially available from Shenyang chemical research institute.

The infrared absorbing dye ADS830 used in the comparative examples is available from Qingdao blue Safan New materials, having the following structure:

example 1

Preparing a substrate: a1050-rolled aluminum plate having a purity of 99.5% and a thickness of 0.3mm was immersed in a 5% aqueous solution of sodium hydroxide at 70 ℃ for 20 seconds, washed with running water, and immediately neutralized with A1% aqueous solution of nitric acid. Then, the mixture was subjected to a sine wave alternating current at 40 ℃ in a 1% hydrochloric acid aqueous solution at a frequency of 50A/dm²The resultant was subjected to electrolytic roughening at a current density of 16 seconds, followed by neutralization with a 5% aqueous solution of sodium hydroxide at 40 ℃ for 10 seconds, and washing with water. Finally, at 30 ℃, using 20% sulfuric acid water solution at 15A/dm²Current density of (2), anodizing for 20 seconds, and water washing. Sealing with 5% sodium silicate aqueous solution at 80 deg.C for 18 s, washing with water, and drying to obtain a plate base with average thickness of central line of 0.5 μm and oxide film weight of 3.0g/dm²。

Coating a heat-sensitive layer: the following photosensitive liquid (i.e., the heat-sensitive layer composition) was extrusion-coated on the above-mentioned hydrophilized plate base, and then dried at 100 ℃ for 60 seconds to obtain 10mg/dm²Dry weight of coating (2). The photosensitive solution used was the following composition (each component in parts by weight):

special heat-sensitive resin L190

Crosslinking agent P5

Diaryl iodonium hexafluorophosphate 3

Thermochromic dye D2

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 2

The plate base and the thermosensitive layer are prepared by the same method, and the photosensitive solution comprises the following components:

special heat-sensitive resin L185

Crosslinking agent P10

Diaryl iodonium hexafluorophosphate 3

Thermochromic dye D2

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 3

special heat-sensitive resin L180

Crosslinking agent P15

Diaryl iodonium hexafluorophosphate 3

Thermochromic dye D2

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 4

special heat-sensitive resin L275

Crosslinking agent P20

Diaryl iodonium hexafluorophosphate 3

Thermochromic dye D2

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 5

special heat-sensitive resin L270

Crosslinking agent P25

Diaryl iodonium hexafluorophosphate 3

Thermochromic dye D2

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 6

special heat-sensitive resin L265

Crosslinking agent P30

Diaryl iodonium hexafluorophosphate 3

Thermochromic dye D2

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 7

special heat-sensitive resin L360

Crosslinking agent P30

Diaryl iodonium hexafluorophosphate 5

Thermochromic dye D5

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 8

special heat-sensitive resin L355

Crosslinking agent P15

Diaryl iodonium hexafluorophosphate 15

Thermochromic dye D15

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 9

special heat-sensitive resin L350

Crosslinking agent P30

Diaryl iodonium hexafluorophosphate salt 10

Thermochromic dye D10

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 10

special heat-sensitive resin L485

Crosslinking agent P10

Diaryl iodonium hexafluorophosphate 3

Thermochromic dye D2

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 11

special heat-sensitive resin L585

Crosslinking agent P10

Diaryl iodonium hexafluorophosphate 3

Thermochromic dye D2

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 12

special heat-sensitive resin L685

Crosslinking agent P10

Diaryl iodonium hexafluorophosphate 3

Thermochromic dye D2

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 13

special heat-sensitive resin L785

Crosslinking agent P10

Diaryl iodonium hexafluorophosphate 3

Thermochromic dye D2

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 14

special heat-sensitive resin L885

Crosslinking agent P10

Diaryl iodonium hexafluorophosphate 3

Thermochromic dye D2

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 15

special heat-sensitive resin L985

Crosslinking agent P10

Diaryl iodonium hexafluorophosphate 3

Thermochromic dye D2

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 16

special heat-sensitive resin L1085

Crosslinking agent P10

Diaryl iodonium hexafluorophosphate 4

Thermochromic dye D1

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 17

special heat-sensitive resin L1185

Crosslinking agent P10

Diaryl iodonium hexafluorophosphate 1

Thermochromic dye D4

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

Example 18

A substrate and a heat-sensitive layer were prepared in the same manner as in example 1, except that the average thickness of the center line of the substrate was 0.4. mu.m.

Example 19

A substrate and a heat-sensitive layer were prepared in the same manner as in example 1, except that the average thickness of the center line of the substrate was 0.6. mu.m.

Example 20

A plate base, a heat-sensitive layer, was prepared in the same manner as in example 1, except that the dry coating weight of the photosensitive layer was adjusted to 8mg/dm²。

Example 21

A plate base, a heat-sensitive layer, was prepared in the same manner as in example 1 except that the weight of the photosensitive layer in dry coating was 15mg/dm²。

Comparative examples 1 to 5

The plate base and the heat-sensitive layer were prepared in the same manner as in example 1. The following components were used for the photosensitive liquid:

polymer A1-A570

Pentaerythritol triacrylate 15

Hydroxypropyl cellulose 10

Diaryl iodonium hexafluorophosphate 2.5

Thermosensitive dye ADS 8301

Nitroxyl radical piperidinol 0.5

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

That is, the photosensitive liquids of comparative examples 1 to 5 were obtained by using the polymers A1 to A5 in the order of 70 parts and the same amount of the other raw materials.

Coating an oxygen barrier layer: the following oxygen barrier layer solution was extrusion-coated on the thermosensitive layer obtained above, and then dried at 110 ℃ for 60 seconds. 10mg/dm was obtained²Dry weight of coating (parts by weight of each component).

Formula of oxygen barrier layer (each component is in weight portion)

Polyvinyl alcohol PVA-205 (Colorado, Japan) 17

Polyvinylpyrrolidone PVPK30 (BASF, Germany) 3

Emulsifier OP-10 (Hamm Germany) 0.45

Deionized water 480

Comparative examples 6 to 10

polymer K1-K570

Pentaerythritol triacrylate 25

Diaryl iodonium hexafluorophosphate 2.5

Thermosensitive dye ADS 8301

Nitroxyl radical piperidinol 0.5

0.5 parts of basic brilliant blue

Surfactant (BYK 306) 0.5

Methyl ethyl ketone 200

1-methoxy-2-propanol 700

That is, the above-mentioned polymers K1 to K5 were 70 parts in this order, and the other raw materials and the amounts thereof were the same, to obtain the photosensitive liquids of comparative examples 6 to 10 in this order.

Coating an oxygen barrier layer: the following oxygen barrier layer solution was extrusion-coated on the thermosensitive layer obtained above, and then dried at 110 ℃ for 60 seconds. A dry coating weight of 10mg/dm2 was obtained (parts by weight of each component).

Formula of oxygen barrier layer (each component is in weight portion)

Polyvinyl alcohol PVA-205 (Colorado, Japan) 17

Polyvinylpyrrolidone PVPK30 (BASF, Germany) 3

Emulsifier OP-10 (Hamm Germany) 0.45

Deionized water 480

Application detection:

1. mesh point reduction: the plate material is exposed on a Kodak full win thermosensitive CTP plate making machine at the energy of 120mJ/cm2 to test whether the plate material can reproduce 1-99% of dots, 1-99% is optimal, 2-99% is the best, 3-98% is the next, and so on. The properties are shown in Table 1;

2. contrast Δ E1: the plate material is exposed on a Kodak win-win thermosensitive CTP plate making machine at the energy of 120mJ/cm2, the difference value between 100% field exposure density and the density of an unexposed part is tested, the larger the contrast delta E1 is, the higher the identifiability of an image by naked eyes is, and the higher the automatic identifiability of an image cross line after scanning exposure by a computer system of a printing machine is. The properties are shown in Table 1;

3. color difference Δ E2: the plate material is exposed on a Kodak full-win thermosensitive CTP plate making machine at the energy of 160mJ/cm2 and 80mJ/cm2, the density difference of 100% of black ink of a printing product of the plate material and the black ink in the field with different exposure amounts is tested, the smaller the color difference delta E2 is, the larger the exposure latitude of the plate material is, and the better the color uniformity of the exposed printing products of different types of exposure machines is. The properties are shown in Table 1;

4. water display time: the plate material is exposed on a Kodak full-win thermosensitive CTP platemaking machine at the energy of 120mJ/cm2, the time (unit: second) consumed for removing an unexposed coating layer by water development at the temperature of 25 ℃ is tested, and the shorter the water development time is, the better the low chemical developability of the plate material is. The properties are shown in Table 1;

5. number of passing papers: the plate material is exposed on a Kodak full-win thermosensitive CTP plate making machine at the energy of 120mJ/cm2, the plate material is directly put on a printing machine and is developed under the action of a fountain solution, the paper is provided with an unexposed layer, the number of consumed paper (unit: sheet) before the printing product is normal is tested, and the smaller the number of paper passing through the plate is, the better the on-machine development performance of the plate material is. The properties are shown in Table 1;

6. printing resistance: the plate material is exposed on a Kodak win-win thermosensitive CTP plate making machine at the energy of 120mJ/cm2, prints are printed on a northern four-color rotary press, the number of the prints which can be printed is tested, and the higher the number of the prints is, the better the plate material quality is. The properties are shown in Table 1;

the detection application results in table 1 show that, compared with other environment-friendly thermal plates, the environment-friendly thermal plate designed by the invention improves the sensitivity of the plate material and improves the dot quality of the plate material through a double imaging mechanism of cationic polymerization and urethane reaction; the thermosetting high-wear-resistance urethane bond net-shaped cross-linking structure is introduced through the cross-linking agent, so that the printing resistance of the plate is improved; the problem of color reduction uniformity of an image layer is improved by improving the exposure tolerance; the thermosensitive color-changing dye with a special structure is selected to improve the plate making contrast of the plate material, so that the problem of automatic plate material identification by a computer is solved; the plate material has a hydroxyethylation acrylamide hydrophilic unit, can realize water development or on-press development, and is a green and environment-friendly thermosensitive plate.

TABLE 1 plate application Performance Table

While the preferred embodiments of the present invention have been described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

Claims

1. A heat-sensitive resin characterized by: the thermosensitive resin is monomer a: methacrylamide, monomer b: hydroxyethyl acrylamide and monomer c: the ternary free radical copolymer of 3, 4-epoxy cyclohexyl methyl acrylate has methacrylamide unit in 40-80 wt%, hydroxyethyl acrylamide unit in 10-30 wt% and 3, 4-epoxy cyclohexyl methyl acrylate unit in 10-30 wt%.

2. A thermosensitive resin according to claim 1, wherein: the weight-average molecular weight of the thermal sensitive resin is 4000-150000, and the glass transition temperature is 110-130 ℃.

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

4. An environment-friendly thermosensitive plate is characterized in that: the thermosensitive plate comprising a hydrophilic support and a thermosensitive layer, wherein the thermosensitive layer contains the thermosensitive resin according to claim 1 or 2, a crosslinking agent, a thermal initiator, and a thermosensitive color-changing dye; the heat-sensitive resin accounts for 50-90% of the total solid content of the heat-sensitive layer composition, the cross-linking agent accounts for 5-30% of the total solid content of the heat-sensitive layer composition, the thermal initiator accounts for 1-15% of the total solid content of the heat-sensitive layer composition, and the heat-sensitive color-changing dye accounts for 1-15% of the total solid content of the heat-sensitive layer composition.

5. The environmentally friendly thermal plate according to claim 4, wherein: the cross-linking agent has the following structure:

。

6. the environmentally friendly thermal plate according to claim 4, wherein: the heat-sensitive layer comprises, by weight, 60-80% of heat-sensitive resin, 10-20% of cross-linking agent, 1-10% of thermal initiator and 1-10% of heat-sensitive color-changing dye.

7. The environmentally friendly thermal plate according to claim 4, wherein: the thermal initiator is selected from one or more of iodonium salt and sulfonium salt, and the decomposition temperature is 150-220 ℃; the thermochromic dye is a thermochromic azamethine dye; the hydrophilic carrier is an aluminum plate base which is subjected to electrolytic coarsening and anodic oxidation and hole sealing treatment, and the average thickness of the central line is 0.4-0.6 mu m.

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

9. The method for preparing an environmentally friendly thermal plate according to claim 4, wherein: the method comprises the following specific steps: (1) treating an aluminum plate base hydrophilic carrier; (2) coating the treated hydrophilic carrier of the aluminum plate base with a heat-sensitive layer, wherein the coating dry weight of the heat-sensitive layer is 8-15mg/dm²。

10. The method for applying the environment-friendly thermosensitive plate according to claim 4, wherein: the lithographic plate is scanned and exposed by a thermosensitive CTP plate making machine, and is developed by water washing or directly mounted on a printing machine and developed and printed by a fountain solution of the printing machine.