Hot-melting core-shell emulsion particles, preparation method thereof, treatment-free thermosensitive plate precursor containing hot-melting core-shell emulsion particles, treatment-free thermosensitive plate and application of hot-melting core-shell emulsion particles and treatment-free thermosensitive plate precursor

Abstract

The invention discloses a hot-melt core-shell emulsion particle and a preparation method thereof, a treatment-free thermo-sensitive plate precursor containing the hot-melt core-shell emulsion particle, a treatment-free thermo-sensitive plate and application of the hot-melt core-shell emulsion particle and the treatment-free thermo-sensitive plate. The hot-melt core-shell emulsion particle comprises a core layer and a shell layer, and raw materials corresponding to a copolymerization unit of the core layer comprise styrene, acrylonitrile and a water-resistant reactive emulsifier; the corresponding raw materials of the shell layer copolymerization unit comprise vinyl oxetane, butyl methacrylate and a hydrophilic reactive emulsifier. The problem that the imaging capability, the on-machine developing capability and the pressrun of the treatment-free thermosensitive plate are difficult to consider at the same time is effectively solved.

Description

Technical Field

[0001] This invention belongs to the field of advanced lithographic printing technology, specifically to hot-melt core-shell emulsion particles, their preparation method, and a process-free thermal plate precursor and process-free thermal plate containing the same, as well as their applications. This application relates to green printing materials under the strategic emerging industries catalogue, under the key direction of 3.1 New Functional Materials Industry within the 3 New Materials Industry, 3.19 Ecological and Environmental Materials. Background Art

[0002] Early CTP (computer-to-plate) technology relied on chemical development processes. For example, silver salt diffusion transfer plates required the use of silver-containing emulsions and physical development core layers, while photopolymer plates relied on alkaline developers. These processes had the following problems: 1. Environmental pollution: The developer waste liquid contains heavy metals (such as silver) and toxic organic matter, which has high treatment costs and does not meet environmental requirements; 2. Complex processes: Developing equipment and chemical solution management systems are required, which increases equipment investment and maintenance costs; 3. Fluctuations in platemaking quality: Changes in development parameters (such as temperature and concentration) may lead to unstable dot reproducibility.

[0003] The background technology of treatment-free thermal plates originates from the printing industry's continuous pursuit of environmental protection and efficiency. Its core lies in replacing the chemical development link in the platemaking process through technological innovation, thereby reducing pollution and improving production efficiency.

[0004] Process-free thermal plates can be divided into direct-on-press process-free thermal plates and low-chemical development process-free thermal plates. Direct-on-press process-free thermal plates can be directly loaded onto the press after imaging, where they are developed and printed using the printing press's fountain solution. Low-chemical development process-free thermal plates, after exposure and imaging on the platesetter, do not require a strong alkaline chemical developer and can be developed with just water washing before printing.

[0005] Process-free thermal plate technology can be categorized into thermal ablation, phase change, and hot melt. Thermal ablation involves laser ablating the oleophilic coating to expose the hydrophilic area of ​​the aluminum plate. Phase change involves laser-induced polymer conversion from hydrophilic to oleophilic. Hot melt involves laser-induced melting of thermoplastic polymer particles, converting the hydrophilic to hydrophobic properties.

[0006] The performance of process-free thermal plates is enhanced through the design of thermally responsive materials and the optimization of imaging mechanisms. Developing precursor materials for process-free thermal plates and optimizing imaging mechanisms are the primary approaches to improving the performance of process-free thermal plates.

[0007] Currently, one of the mainstream technologies for processing-free thermal plates is laser hot-melt technology. The emulsion particles achieve hydrophilic development, and the laser causes the emulsion particles to hot-melt, achieving demulsification and lipophilicity. Therefore, emulsion particles are widely used in the development of processing-free thermal plates. For example, WO94 / 23954 introduces hot-melt microcapsule technology; US4004924 introduces a mixture of thermoplastic hydrophobic particles and hydrophilic binders; EP 2006-5-24 06114475.4 introduces hot-melt thermoplastic particles.

[0008] Traditional emulsion particles used in process-free thermal plates have certain drawbacks. The emulsion's internal and external structures are simple, without functional partitioning. To balance the contradiction between development and imaging, the emulsion particles must meet the following conditions: 1. The inner layer of the emulsion needs to be hard to provide mechanical support, while the outer layer needs to be softer to facilitate thermal melt imaging. 2. The inner layer does not need to be too hydrophilic, as it exhibits lipophilicity after laser thermal melting, while the outer layer needs to be highly hydrophilic to enable on-press development. 3. The inner layer of the emulsion is difficult for initiators and infrared dyes to enter, and generally does not require the presence of thermosensitive groups to avoid causing core collapse and affecting imaging accuracy. However, the outer layer of the emulsion is easily accessible to initiators and infrared dyes, ensuring imaging performance. Therefore, the traditional emulsion's simple internal and external structures make it difficult to balance the aforementioned contradictions between development and imaging. Summary of the Invention

[0009] In order to solve the above problems, the present invention provides a hot-melt core-shell emulsion particle and a preparation method thereof, as well as a treatment-free heat-sensitive plate precursor and a treatment-free heat-sensitive plate containing the same and its application. The raw materials corresponding to the core layer copolymerization unit of the hot-melt core-shell emulsion particle include styrene, acrylonitrile, and a water-resistant reactive emulsifier. Styrene and acrylonitrile can provide rigid mechanical support for the core layer of the hot-melt core-shell emulsion particle. The water-resistant reactive emulsifier provided in this application can make styrene and acrylonitrile more effectively form seeds and nucleate. Acrylonitrile has solvent resistance and staining resistance, so that the core layer can resist the penetration of solvents in ink into the core layer. The layer causes the inner core to collapse, and at the same time it can resist the penetration of dyes and initiators to avoid reducing the initiation efficiency. The water-resistant reactive emulsifier does not affect the ink affinity after imaging, and at the same time can improve the resistance to fountain solution erosion; the raw materials corresponding to the shell copolymer unit include vinyl oxetane, butyl methacrylate, and hydrophilic reactive emulsifier. Butyl methacrylate is beneficial to improving the adhesion of the emulsion particles. The copolymer unit formed by the hydrophilic reactive emulsifier is beneficial to improving the on-machine development ability. The copolymer unit also contains oxetane, has thermal cross-linking properties, and can improve the thermal imaging performance of the plate.

[0010] The object of the present invention is achieved in the following manner: A hot-melt core-shell emulsion particle comprises a core layer and a shell layer. The raw materials corresponding to the core layer copolymerization unit include styrene, acrylonitrile, and a water-resistant reactive emulsifier, and the raw materials corresponding to the shell layer copolymerization unit include vinyl oxetane, butyl methacrylate, and a hydrophilic reactive emulsifier.

[0011] Vinyl oxetane has the following structure: Structure 1 R1 is methylene or carbonyl, R2 is methyl or hydrogen; The water-resistant reactive emulsifier is allyl fatty alcohol polyether ammonium sulfate, and its structure is as follows: Structure 2 R3 is a long-chain alkyl group with ≥12 C atoms or a long-chain alkylphenyl group with ≥9 C atoms; The hydrophilic reactive emulsifier is 2-acrylamido-2-methylpropanesulfonic acid.

[0012] The weight ratio of styrene, acrylonitrile and water-resistant reactive emulsifier in the raw materials corresponding to the core copolymer units is: styrene: acrylonitrile: water-resistant reactive emulsifier is 30-40:10-20:3-6; the weight ratio of vinyl oxetane: butyl methacrylate: hydrophilic reactive emulsifier in the raw materials corresponding to the shell copolymer units is: vinyl oxetane: butyl methacrylate: hydrophilic reactive emulsifier is 10-20:30-40:5-10.

[0013] The preparation method of the hot-melt core-shell emulsion particles is a step-by-step polymerization method of forming seed crystals → core layer polymerization → shell layer polymerization: first, a portion of the core layer pre-emulsion containing the raw materials corresponding to the core layer copolymerization units is added to deionized water with mechanical stirring and nitrogen protection for heating reaction to form seed crystals, and then the remaining core layer pre-emulsion containing the raw materials corresponding to the core layer copolymerization units is added dropwise to react to form a core layer. After a certain reaction time, the shell layer pre-emulsion containing the raw materials corresponding to the shell layer copolymerization units is added dropwise to continue the reaction. After the addition is completed, the reaction is continued for a certain time, and then the temperature is lowered to terminate the reaction.

[0014] The method for preparing the hot-melt core-shell emulsion particles comprises the following steps: (1) Preparing a core layer pre-emulsion containing raw materials corresponding to the core layer copolymer units: stirring a mixture of styrene, acrylonitrile, a water-resistant reactive emulsifier, an initiator, and deionized water at 200-300 rpm and room temperature for at least 30 minutes to form a stable core layer pre-emulsion; (2) preparing a shell pre-emulsion containing raw materials corresponding to the shell copolymer units: stirring a mixture of vinyl oxetane, butyl methacrylate, a hydrophilic reactive emulsifier, an initiator, and ionized water at room temperature for at least 30 minutes under stirring at 200-300 rpm to form a stable shell pre-emulsion; steps (1) and (2) are performed in no particular order; (3) At 200-300 rpm: add 3-5 parts of the core layer pre-emulsion to 160-240 parts of deionized water, and react at 70-80°C under nitrogen protection until the system changes from a transparent state to a turbid state instantly. Start timing. After reacting for 30-40 minutes, add the remaining core layer pre-emulsion dropwise within 2-3 hours. After the addition is complete, react for another 3-4 hours. Then, add the shell layer pre-emulsion dropwise within 3-4 hours. After the addition is complete, react for another 3-4 hours. Cool to room temperature to terminate the reaction.

[0015] The initiator is ammonium persulfate or azobisisobutyronitrile.

[0016] A processing-free heat-sensitive plate precursor comprises a carrier and an imaging layer, wherein the imaging layer comprises hot-melt core-shell emulsion particles, a cross-linkable prepolymer, a thermal initiator and an infrared absorber, and the hot-melt core-shell emulsion particles are the hot-melt core-shell emulsion particles described in any one of claims 1 to 6.

[0017] In the imaging layer, by weight percentage, the hot-melt core-shell emulsion particles account for 40-70% of the total solid content of the composition, the cross-linkable prepolymer accounts for 20-40% of the total solid content of the composition, the thermal initiator accounts for 5-13% of the total solid content of the composition, and the infrared absorber accounts for 3-10% of the total solid content of the composition.

[0018] A protective layer is also provided on the imaging layer; The crosslinkable prepolymer is a crosslinkable prepolymer containing double bonds or epoxy bonds or a mixture thereof, or a crosslinkable prepolymer containing both double bonds and epoxy bonds; The thermal initiator is an iodonium salt; The infrared absorber is a cyanine dye with an absorption peak at 750-850 nm; The carrier is an aluminum plate that has been electrolytically roughened and anodized.

[0019] A process-free heat-sensitive plate is prepared from the process-free heat-sensitive plate precursor.

[0020] The application of the treatment-free thermal plate is that after being scanned and exposed by a thermal CTP platemaking machine, the treatment-free thermal plate is washed with water and developed before being mounted on a printing press for printing or directly mounted on a printing press for development and printing with a printing press fountain solution.

[0021] Compared with the prior art, the present invention provides a hot-melt core-shell emulsion particle and a preparation method thereof, a treatment-free heat-sensitive plate precursor and a treatment-free heat-sensitive plate containing the same, and applications. The raw materials corresponding to the core layer copolymerization unit of the hot-melt core-shell emulsion particle include styrene, acrylonitrile, and a water-resistant reactive emulsifier. Styrene and acrylonitrile can provide rigid mechanical support for the core layer of the hot-melt core-shell emulsion particle. The water-resistant reactive emulsifier provided in this application can enable styrene and acrylonitrile to form seeds and nuclei more effectively. Acrylonitrile has solvent resistance and staining resistance, so that the core layer can resist the penetration of solvents in ink into the core layer. The layer causes the inner core to collapse, and at the same time it can resist the penetration of dyes and initiators to avoid reducing the initiation efficiency. The water-resistant reactive emulsifier does not affect the ink affinity after imaging, and at the same time can improve the resistance to fountain solution erosion; the raw materials corresponding to the shell copolymer unit include vinyl oxetane, butyl methacrylate, and hydrophilic reactive emulsifier. Butyl methacrylate is beneficial to improving the adhesion of the emulsion particles. The copolymer unit formed by the hydrophilic reactive emulsifier is beneficial to improving the on-machine development ability. The copolymer unit also contains oxetane, has thermal cross-linking properties, and can improve the thermal imaging performance of the plate. DETAILED DESCRIPTION

[0022] A hot-melt core-shell emulsion particle, wherein the raw materials corresponding to the core copolymerization unit of the hot-melt core-shell emulsion particle include styrene, acrylonitrile, and a water-resistant reactive emulsifier, and the raw materials corresponding to the shell copolymerization unit include vinyl oxetane, butyl methacrylate, and a hydrophilic reactive emulsifier, wherein the vinyl oxetane has the following structure: Structure 1 R1 is methylene or carbonyl, and R2 is methyl or hydrogen.

[0023] The hot-melt core-shell emulsion particles disclosed in the present invention are a new functionally partitioned material. The raw materials corresponding to the core layer copolymer units include styrene, acrylonitrile, and a water-resistant reactive emulsifier. The benzene rings of styrene are rigid, and acrylonitrile provides a hard segment copolymer unit. The two can provide rigid mechanical support for the hot-melt core-shell emulsion particles. Acrylonitrile has excellent solvent resistance and staining resistance, enabling the core layer to resist the penetration of solvents in ink into the core layer and cause the core to collapse. It can also resist the penetration of dyes and initiators to avoid reducing the initiation efficiency. The water-resistant reactive emulsifier is allyl fatty alcohol polyether ammonium sulfate, which has the following structure: Structure 2 R3 is a long-chain alkyl group (number of carbon atoms ≥ 12) or a long-chain alkyl group (number of carbon atoms ≥ 9) phenyl group, preferably a dodecyl group or a p-nonylphenyl group; Examples of water-resistant reactive emulsifiers include, but are not limited to, the following structures: A1; A2: This type of emulsifier is a polyether anionic emulsifier with an alkyl hydrophobic group, and can make styrene and acrylonitrile form seeds and nuclei more effectively. At the same time, it contains long-chain alkyl or long-chain alkylphenyl groups, which ensures effective emulsification while being water-resistant. It will not significantly increase the hydrophilicity of the emulsion particles, does not affect the ink affinity after imaging, and can improve the resistance to fountain solution erosion.

[0024] The raw materials corresponding to the shell copolymerization unit of the hot-melt core-shell emulsion particles include vinyl oxetane, butyl methacrylate, and a hydrophilic reactive emulsifier, wherein the vinyl oxetane has the following structure: Structure 1 R1 is methylene or carbonyl, and R2 is methyl or hydrogen.

[0025] The vinyl oxetane of structure 1 may include the following structures, but is not limited thereto: C1: C2: C3: Vinyl oxetane exhibits cationic polymerization properties. When the iodonium salt initiator in the treatment-free thermal plate initiation system is cracked by laser heat, it generates free radicals and cations. These initiate cationic and free radical polymerization of the copolymer units formed by vinyl oxetane and the crosslinkable prepolymer in the imaging layer, achieving imaging using a hybrid mechanism of thermal-sensitive cationic and free radical polymerization, which is more precise than imaging using free radical polymerization alone. Butyl methacrylate, a soft comonomer in the shell copolymer units of the hot-melt core-shell emulsion particles, imparts flexibility to the shell layer of the core-shell emulsion. Laser melting facilitates adhesion between particles and to the grain of the plate substrate, helping to improve the plate's printability. The hydrophilic reactive emulsifier provides hydrophilic emulsifying copolymer units, which helps improve the plate's on-press development capabilities. The shell hydrophilic reactive emulsifier is 2-acrylamide-2-methylpropanesulfonic acid, which has stronger hydrophilicity than the water-resistant reactive emulsifier. It can improve the developability of the plate. At the same time, the acrylamide structure has excellent hydrophilic and oil-repellent capabilities, which can provide a layer of anti-solvent protective shell for the hot-melt core-shell emulsion particles, thereby improving the ink erosion ability of the plate.

[0026] The preparation method of the hot-melt core-shell emulsion particles or the emulsion containing the hot-melt core-shell emulsion particles adopts a step-by-step polymerization method of forming seed crystals → core layer polymerization → shell layer polymerization. First, a part of the pre-emulsion containing the core layer copolymerization unit is added to deionized water with mechanical stirring and nitrogen protection for heating reaction to form seed crystals, and then the remaining pre-emulsion containing the core layer copolymerization unit is added dropwise to react to form the core layer. After a certain reaction time, the pre-emulsion containing the shell layer copolymerization unit is added dropwise to continue the reaction. After the addition is completed, the reaction is continued for a certain time, and then the temperature is lowered to terminate the reaction.

[0027] More specifically, the preparation method of the hot-melt core-shell emulsion particles or the emulsion containing the hot-melt core-shell emulsion particles is as follows: a mixture of the raw materials corresponding to the core layer: styrene (30-40 parts), acrylonitrile (10-20 parts), a water-resistant reactive emulsifier (3-6 parts), an initiator (1-1.5 parts), and deionized water (40-60 parts) is stirred at 200-300 rpm and room temperature for at least 30 minutes to form a stable core layer pre-emulsion; 3-5 parts of the core layer pre-emulsion is added to a reactor containing 160-240 parts of deionized water at 200-300 rpm, and the mixture is stirred at 70-80 rpm under nitrogen protection. The reaction is continued at 40°C until the system turns from transparent to turbid. After 30-40 minutes of reaction, the remaining core layer pre-emulsion is added dropwise over 2-3 hours. The reaction continues for another 3-4 hours. The shell layer pre-emulsion, which has been pre-emulsified, is then added dropwise over 3-4 hours. Stirring is performed at 200-300 rpm for at least 30 minutes at room temperature. The pre-emulsified shell layer pre-emulsion comprises: vinyl oxetane (10-20 parts), butyl methacrylate (30-40 parts), a hydrophilic reactive emulsifier (5-10 parts), an initiator (1-1.5 parts), and deionized water (40-60 parts). The reaction continues for another 3-4 hours after the addition is complete. The reaction is terminated by cooling to room temperature. The initiator is preferably a peroxide such as ammonium persulfate or an azo compound such as azobisisobutyronitrile.

[0028] The following sections describe a process-free heat-sensitive plate precursor and a process-free heat-sensitive plate comprising the above-mentioned heat-fusible core-shell emulsion particles and their applications.

[0029] The precursor of the process-free thermal plate refers to the precursor for manufacturing the process-free thermal plate, and generally refers to the necessary materials and technologies required before manufacturing the process-free thermal plate.

[0030] A processing-free heat-sensitive plate precursor comprises a carrier and an imaging layer. The imaging layer comprises hot-melt core-shell emulsion particles, a cross-linkable prepolymer, a thermal initiator and an infrared absorber. The hot-melt core-shell emulsion particles are the hot-melt core-shell emulsion particles described in the present invention.

[0031] The imaging layer of the treatment-free heat-sensitive plate precursor of the present invention comprises, by weight percentage, 40-70% of the total solid content of the composition of the hot-melt core-shell emulsion particles, 20-40% of the total solid content of the composition of the crosslinkable prepolymer, 5-13% of the total solid content of the composition of the thermal initiator, and 3-10% of the total solid content of the infrared absorber.

[0032] The processing-free thermal plate precursor of the present invention may optionally include a protective layer on the imaging layer, which serves as an oxygen barrier and protective layer. The protective layer may be made of a water-soluble polymer with relatively good crystallinity, such as polyvinyl alcohol, polyvinyl pyrrolidone, hydroxypropyl cellulose, gelatin, gum arabic, polyacrylic acid, or the like.

[0033] The cross-linkable prepolymers in the imaging layer are described below: The crosslinkable prepolymer in the imaging layer of the present invention is a crosslinkable prepolymer containing double bonds or epoxy bonds, or a mixture thereof, or a crosslinkable prepolymer containing double bonds or epoxy bonds at the same time, and can undergo free radical polymerization and epoxy bond cationic polymerization. Crosslinkable prepolymers containing double bonds include 1,6-hexanediol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, trimethylolpropane triacrylate, hydroxypropyl glyceryl triacrylate, hydroxyethyl trimethylolpropane triacrylate, polyethylene glycol dimethacrylate, dipentaerythritol hexaacrylate, and condensation products of isocyanates and multifunctional acrylates, such as condensation products of isocyanates with hydroxyethyl acrylate and pentaerythritol triacrylate. , or the condensation product of an isocyanate containing a double bond such as methacryloyloxyisocyanate and a polyhydroxy compound such as pentaerythritol; a cross-linkable prepolymer containing an epoxy bond such as glycidyl methacrylate, 3,4-epoxycyclohexyl methacrylate, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3-((oxiranyl)methyl)oxetane, 3-ethyl-3-(benzyloxymethyl)oxetane, tetraepoxycyclohexyl-2,2,6,8-tetramethylcyclotetrasiloxane, etc.

[0034] The cross-linkable prepolymer in the imaging layer accounts for 20-40% by weight of the total solid content of the imaging layer composition.

[0035] The thermal initiators in the imaging layer are described below: The thermal initiator in the imaging layer of the present invention initiates the crosslinkable components in the system, achieving thermal imaging. The thermal initiator can be an onium salt. Under the action of heat, the onium salt undergoes both homolytic and heterolytic cleavage. Homolytic cleavage generates free radicals that initiate free radical polymerization, while heterolytic cleavage generates cations that initiate cationic polymerization. Therefore, the treatment-free thermal plate produced using the precursor of the present invention exhibits dual imaging capabilities through free radical polymerization and cationic polymerization, resulting in excellent imaging performance. Curing of the imaging layer forms a network-like crosslinked structure with high wear resistance. Onium salts include sulfonium salts, oxysulfonium salts, oxosulfonium salts, sulfoxide onium 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-hydroxytetradecyloxy]-phenyl]phenyliodonium hexafluoroantimonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium octylsulfate, 2-methoxy-4-aminophenyldiazonium hexafluorophosphate, and phenoxyphenyldiazonium hexafluoroantimonate. The thermal initiator of the present invention is selected from iodonium salts capable of both homolytic and heterolytic cleavage, and has a thermal decomposition temperature of 150-200° C. The thermal initiator accounts for 5-13% of the total solid weight of the imaging layer.

[0036] The infrared absorbers in the imaging layer are described below: The infrared absorber in the imaging layer of the present invention primarily functions as an energy transfer agent. Heat from the infrared laser transfers the laser energy to the thermal initiator via the infrared absorber. The thermal initiator then decomposes to produce active radicals, which cause the hot-melt core-shell emulsion particles and the crosslinkable prepolymer to undergo three-dimensional network polymerization, achieving thermal imaging. The infrared absorber has a maximum absorption wavelength range of 750-1100 nm and is selected from carbon black, azo dyes, triarylamine dyes, indolium dyes, oxonol dyes, cyanine dyes, merocyanine dyes, indocyanine dyes, phthalocyanine dyes, polythiophene dyes, pyrazoline azo dyes, oxazine dyes, naphthoquinone dyes, anthraquinone dyes, quinoneimine dyes, methine dyes, porphyrin dyes, and the like. This improves platemaking contrast, facilitating visual plate proofing and detection of image defects by printing operators. It also facilitates modern, highly intelligent printing presses, enabling automated intelligent plate loading through automatic positioning and recognition of crosshair images at the four corners of the plate. The infrared absorber can be selected to have a color-changing function, enabling high-contrast image presentation through laser decomposition. The infrared absorber in the imaging layer of the present invention is preferably a cyanine dye having a wavelength of 750 to 850 nm.

[0037] The infrared absorber in the imaging layer of the present invention accounts for 3-10% by weight of the total solid content of the imaging layer composition.

[0038] The carrier in the process-free heat-sensitive plate precursor of the present invention is described in detail below.

[0039] The imaging layer of the present invention needs to be coated on a carrier, which includes a metal base such as a steel base, a copper base, an aluminum base, etc. The carrier selected in the present invention is an aluminum plate substrate that has been roughened by electrolysis and anodic oxidation.

[0040] The aluminum substrate is made by electrolytic roughening, with an average centerline roughness of 0.3-0.6um. An aluminum substrate with 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 is used. The electrolytic roughening electrolyte can be an aqueous solution of acid, alkali or salt. First, place the aluminum plate in an aqueous solution of 1%-30% sodium hydroxide, potassium hydroxide, sodium carbonate or sodium silicate, etc., and chemically corrode it at a temperature of 20-80°C for 5-250 seconds. Then neutralize it 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 a speed of 5-100A / dm 2 The current density is 10-300 seconds in nitric acid or hydrochloric acid electrolyte. The aluminum substrate treated by electrolytic roughening is then anodized. Anodization is usually carried out using sulfuric acid method, with a concentration of sulfuric acid of 5-30% and a current density of 1-15A / dm 2 The oxidation temperature is 20-60℃ and the oxidation time is 5-250 seconds to form 1-10g / m 2 The aluminum substrate treated by electrolytic roughening and anodizing can be sealed or not. A variety of methods can be used to seal the pores, preferably to seal 50-80% of the volume of the oxide film micropores. For example, a coating with a thickness of 3mg / m 2 Polyvinylphosphonic acid seals the micropores of the oxide film.

[0041] The process-free thermal plate precursor of the present invention can be used to manufacture process-free thermal plates. The steps for manufacturing the process-free thermal plates include at least carrier treatment and imaging layer coating. A protective layer may or may not be applied. Applying a protective layer over the imaging layer reduces the inhibitory effect of oxygen on the performance of the thermal plate imaging layer, while also protecting the imaging layer from environmental contamination and scratching. The protective layer can be made of a water-soluble polymer with relatively good crystallinity, such as polyvinyl alcohol, polyvinyl pyrrolidone, hydroxypropyl cellulose, gelatin, gum arabic, polyacrylic acid, and other water-soluble polymers.

[0042] When using the process-free thermal plate precursor of the present invention to produce a process-free thermal plate, other necessary additives may be added, such as solvents, room-temperature thermal polymerization inhibitors, surfactants, and layer colorants. Solvents are primarily used to prepare the thermal coating photosensitive solution from the thermal composition and include alcohols, ketones, esters, ethers, amides, aromatic solvents, as well as ethylene dichloride and tetrahydrofuran. Solvents can be used in pure or mixed forms. Room-temperature thermal polymerization inhibitors are used to prevent polymerization of the plate at room temperature, thereby improving the plate's room-temperature stability. Thermal polymerization inhibitors include: hydroquinone, nitroxide 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.; the addition of layer colorants is to increase the image density of the thermal plate after platemaking, so as to facilitate visual inspection or image analysis of the thermal plate after platemaking. The plate performance is measured by analytical measuring equipment, including: methyl violet, ethyl violet, crystal violet, crystal inner violet, Victoria blue, oil green, oil blue, oil yellow, rhodamine B, methyl violet, malachite green, methylene blue, triazines, etc.; the imaging layer can be added with surfactants, and non-ionic surfactants, amphoteric surfactants, silicon-containing surfactants, fluorine-containing surfactants, etc. can be selected, such as betaines, glyceryl stearate, palm oil sorbate, polysiloxanes, and polyfluoroalkyl ethers.

[0043] The process-free heat-sensitive plate prepared using the process-free heat-sensitive plate precursor of the present invention is usually coated by techniques known in the art, such as knife coating (including air knife coating), blade coating, strip coating, roller coating, press coating, etc.

[0044] The processing-free thermal plate made from the processing-free thermal plate precursor of the present invention is scanned and exposed by a thermal CTP platemaking machine, and then washed and developed with water before being mounted on a printing press for printing or directly mounted on a printing press for development and printing with a printing press fountain solution.

[0045] The present invention is described in detail below with reference to 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. Those skilled in the art in this field can make some non-essential improvements and adjustments based on the contents of the present invention.

[0046] Part 1: Synthesis examples of thermally fused core-shell emulsion particles (D1-D8) or emulsions containing thermally fused core-shell emulsion particles (D1-D8), but the present invention is not limited to the following examples.

[0047] The main raw materials can be obtained from the following companies: vinyl oxetane C1, C2, and C3 are all from Hubei Gurun Technology Co., Ltd., styrene is from Qilu Petrochemical, acrylonitrile is from Tianjin Chemical Reagent Plant No. 2, water-resistant reactive emulsifiers A1 and A2 are from Japan ADICO Co., Ltd., hydrophilic reactive emulsifier 2-acrylamide-2-methylpropanesulfonic acid is from Jinan Kaichuang Chemical Co., Ltd., ammonium persulfate, azobisisobutyronitrile, and butyl methacrylate are from Bailingwei Chemical Technology Co., Ltd.

[0048] Synthesis of hot-melt core-shell emulsion particles D1 or preparation of an emulsion containing hot-melt core-shell emulsion particles D1: Calculated by weight, a mixture of core layer components: styrene (30 parts), acrylonitrile (10 parts), water-resistant reactive emulsifier A1 (3 parts), ammonium persulfate (1 part), and deionized water (40 parts) was stirred at 200 rpm and room temperature for 30 minutes to form a stable core layer pre-emulsion; 3 parts of the core layer pre-emulsion was added to a reactor containing 160 parts of deionized water at 200 rpm, and the reaction was carried out at 70°C under nitrogen protection until the system instantly changed from a transparent state to a turbid state, and the reaction time was started. After 30 minutes, the remaining core layer pre-emulsion was added dropwise within 2 hours, and the reaction was continued for 3 hours. Then, the shell layer pre-emulsification solution, which had been pre-emulsified by stirring at 200 rpm for 30 minutes at room temperature, was added dropwise within 3 hours: vinyl oxetane C1 (10 parts), butyl methacrylate (30 parts), hydrophilic reactive emulsifier 2-acrylamide-2-methylpropanesulfonic acid (5 parts), ammonium persulfate (1 part), and ionized water (40 parts). After the addition was completed, the reaction was continued for 3 hours, and the temperature was lowered to room temperature to terminate the reaction.

[0049] Synthesis of hot-melt core-shell emulsion particles D2 or preparation of an emulsion containing hot-melt core-shell emulsion particles D2: Calculated by weight, a mixture of the core layer components: styrene (40 parts), acrylonitrile (20 parts), water-resistant reactive emulsifier A2 (6 parts), azobisisobutyronitrile (1.5 parts), and deionized water (60 parts) was stirred at 300 rpm and room temperature for 30 minutes to form a stable core layer pre-emulsion; 5 parts of the core layer pre-emulsion was added to a reactor containing 240 parts of deionized water at 300 rpm, and the reaction was carried out at 80°C under nitrogen protection until the system instantly changed from a transparent state to a turbid state, and the timer was started. After 40 minutes, the remaining core layer pre-emulsion was added dropwise within 3 hours, and the reaction was continued for 4 hours. Then, the shell layer pre-emulsification solution was added dropwise within 4 hours and stirred at room temperature for 30 minutes under stirring at 300 rpm: vinyl oxetane C2 (20 parts), butyl methacrylate (40 parts), hydrophilic reactive emulsifier 2-acrylamide-2-methylpropanesulfonic acid (10 parts), azobisisobutyronitrile (1.5 parts), and ionized water (60 parts). After the addition was completed, the reaction was continued for 4 hours, and the temperature was lowered to room temperature to terminate the reaction.

[0050] Synthesis of hot-melt core-shell emulsion particles D3 or preparation of an emulsion containing hot-melt core-shell emulsion particles D3: Calculated by weight, a mixture of core layer components: styrene (35 parts), acrylonitrile (15 parts), water-resistant reactive emulsifier A1 (5 parts), ammonium persulfate (1.25 parts), and deionized water (50 parts) was stirred at 250 rpm at room temperature for 35 minutes to form a stable core layer pre-emulsion; 4 parts of the core layer pre-emulsion was added to a reactor containing 200 parts of deionized water at 250 rpm, and the reaction was carried out at 75°C under nitrogen protection until the system instantly changed from a transparent state to a turbid state. The timer was started after the reaction for 35 minutes. , dropwise add the remaining core layer pre-emulsion within 2.5 hours, react for 3.5 hours after addition, then dropwise add the pre-emulsified shell layer pre-emulsion at room temperature for 30 minutes under stirring at 250 rpm: vinyl oxetane C3 (15 parts), butyl methacrylate (35 parts), hydrophilic reactive emulsifier 2-acrylamide-2-methylpropanesulfonic acid (7.5 parts), azobisisobutyronitrile (1.25 parts), ionized water (50 parts) within 3.5 hours, react for 3.5 hours after addition, and cool to room temperature to terminate the reaction.

[0051] Synthesis of hot-melt core-shell emulsion particles D4 or preparation of an emulsion containing hot-melt core-shell emulsion particles D4: Calculated by weight, a mixture of the core layer components: styrene (40 parts), acrylonitrile (10 parts), water-resistant reactive emulsifier A1 (5 parts), ammonium persulfate (1.25 parts), and deionized water (50 parts) was stirred at 250 rpm at room temperature for 33 minutes to form a stable core layer pre-emulsion; 4 parts of the core layer pre-emulsion was added to a reactor containing 200 parts of deionized water at 250 rpm, and the reaction was carried out at 75°C under nitrogen protection until the system instantly changed from a transparent state to a turbid state. The reaction time was started and the reaction lasted for 35 minutes. Then, the remaining core layer pre-emulsion was added dropwise within 2.5 hours, and the reaction was continued for 3.5 hours. Then, the shell layer pre-emulsification solution, which had been pre-emulsified under stirring at 250 rpm for 30 minutes at room temperature, was added dropwise within 3.5 hours: vinyl oxetane C1 (20 parts), butyl methacrylate (30 parts), hydrophilic reactive emulsifier 2-acrylamide-2-methylpropanesulfonic acid (7.5 parts), ammonium persulfate (1.25 parts), and ionized water (50 parts). After the addition was completed, the reaction was continued for 3.5 hours, and the temperature was lowered to room temperature to terminate the reaction.

[0052] Synthesis of hot-melt core-shell emulsion particles D5 or preparation of an emulsion containing hot-melt core-shell emulsion particles D5: Calculated by weight, a mixture of the core layer components: styrene (30 parts), acrylonitrile (20 parts), water-resistant reactive emulsifier A2 (5 parts), azobisisobutyronitrile (1.25 parts), and deionized water (50 parts) was stirred at 250 rpm and room temperature for 38 minutes to form a stable core layer pre-emulsion; 4 parts of the core layer pre-emulsion was added to a reactor containing 200 parts of deionized water at 250 rpm, and the reaction was carried out at 70-80°C under nitrogen protection until the system instantly changed from a transparent state to a turbid state, and the reaction time was started. After 40 minutes, the remaining core layer pre-emulsion was added dropwise within 2.5 hours, and the mixture was reacted for another 4 hours. Then, the shell layer pre-emulsification solution, which had been pre-emulsified by stirring at 250 rpm for 30 minutes at room temperature, was added dropwise within 4 hours: vinyl oxetane C2 (10 parts), butyl methacrylate (40 parts), hydrophilic reactive emulsifier 2-acrylamide-2-methylpropanesulfonic acid (7.5 parts), azobisisobutyronitrile (1.25 parts), and ionized water (50 parts). The mixture was reacted for another 4 hours after the addition was completed, and the temperature was lowered to room temperature to terminate the reaction.

[0053] Comparative Example Emulsion Synthesis: 1. Agfa Emulsion Particles F: According to Agfa patent EP 2006-5-24 06114475.4, Agfa Emulsion Particles F are synthesized. Agfa Emulsion Particles do not contain reactive emulsifiers. Emulsification relies on the surfactant sodium lauryl sulfate. Agfa Emulsion Particles are not core-shell emulsion particles. Agfa Emulsion Particle Structure: The basic steps for synthesizing Agfa Emulsion Granule F are as follows: 75 g of deionized water, 250 g of isopropyl alcohol, and 5 g of sodium lauryl sulfate were added to a 1000 ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, reflux, and nitrogen protection. 60 g (60 wt%) of St (styrene), 40 g (40 wt%) of AN (acrylonitrile), and 0.7 g of AIBN (azobisisobutyronitrile) were then added dropwise at 80°C for 0.5 hours. After an additional 7.5 hours of reaction, an additional 0.3 g of AIBN (azobisisobutyronitrile) was added and the reaction continued for an additional 12 hours.

[0054] 2. Kodak Emulsion Particle K: Kodak Emulsion Particle K was synthesized according to Kodak patent US 2005-8-3 11 / 196. Kodak Emulsion Particle K contains polyether hydrophilic groups but no epoxy groups. It is not a core-shell emulsion particle. The structure of Kodak Emulsion Particle K is as follows: The basic operation of Kodak emulsion particle K synthesis is as follows: 75g of deionized water and 250g of n-propanol are added to a 1000ml four-necked flask equipped with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection devices, and 20g (20 wt%) of St (styrene), 70g (70 wt%) of AN (acrylonitrile), 10g (10 wt%) of PEGMA (polyethoxymethyl acrylate) and AIBN (azobisisobutyronitrile) are added dropwise at 80°C for 0.5 hour. After reacting for 7.5 hours, 0.3g of AIBN (azobisisobutyronitrile) is added and the reaction is continued for another 12 hours before the reaction is completed.

[0055] 3. Referring to the synthesis of the hot-melt core-shell emulsion particles D1 or the preparation of the emulsion containing the hot-melt core-shell emulsion particles D1, synthesize and compare non-core-shell emulsion particles d1 or prepare an emulsion containing the emulsion particles d1: Calculated by weight, styrene (30 parts), acrylonitrile (10 parts), water-resistant reactive emulsifier A1 (3 parts), ammonium persulfate (2 parts), vinyl oxetane C1 (10 parts), butyl methacrylate (30 parts), and hydrophilic reactive emulsifier (5 parts) are added dropwise to deionized water (240 parts) and reacted for 3 hours. After the addition is completed, the reaction is continued for 5 hours, and the temperature is cooled to room temperature to terminate the reaction.

[0056] 4. Referring to the synthesis of the heat-melting core-shell emulsion particles D5 or the preparation of the emulsion containing the heat-melting core-shell emulsion particles D5, synthesize the non-core-shell comparative emulsion particles d5 without the heat-sensitive component oxetane component or prepare the emulsion containing the emulsion particles d5: Calculated by weight, the core layer components: styrene (30 parts), acrylonitrile (20 parts), water-resistant reactive emulsifier A2 (5 parts), azobisisobutyronitrile (2.5 parts), butyl methacrylate (40 parts), and hydrophilic reactive emulsifier (7.5 parts) were added dropwise to 270 parts of deionized water for reaction over a period of 3 hours. After the addition was complete, the reaction continued for another 4 hours, and the temperature was lowered to room temperature to terminate the reaction.

[0057] Part II: The following are examples of heat-sensitive plates free of processing according to the present invention, but the present invention is not limited to the following examples.

[0058] Example 1 Preparation of the plate base: A1050 rolled aluminum plate with a purity of 99.5% and a thickness of 0.3mm was etched in a 5% sodium hydroxide aqueous solution at 70℃ 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 at 40℃, a sinusoidal AC current of 50A / dm was used to etch the plate base. 2 The surface was electrolytically roughened for 16 seconds at a current density of 10A / dm, then neutralized with a 5% sodium hydroxide aqueous solution at 40°C for 10 seconds and washed with water. Finally, the surface was electrolytically roughened with a 20% sulfuric acid aqueous solution at 30°C at a current density of 15A / dm 2 The current density was set at 1000 nm, anodized for 20 seconds, and washed with water. The pores were sealed with a 5% sodium silicate aqueous solution at 80°C for 18 seconds, washed with water, and dried. The plate substrate thus obtained had an average centerline roughness of 0.5 μm and an oxide film weight of 3.0 g / dm 2 .

[0059] Imaging layer materials: Infrared absorber: obtained from Dye Chemical Company, having the following structure: Code: IR830 Cross-linkable prepolymer: Multifunctional acrylate (codename: SR399) is dipentaerythritol pentaacrylate, sourced from Sartomer; Multifunctional polyurethane acrylate (codename: UN-100) is polyurethane acrylate, a condensation product of Covestro's Desmodurn 100, hydroxyethyl acrylate, and pentaerythritol triacrylate, sourced from Negami Chemical Corporation; 3-ethyl-3-hydroxymethyloxetane (codename: OXT-1) and 3,3'-(oxybis(methylidene)bis(3-ethyl)oxetane (codename: OXT-3) are sourced from Hubei Gurun Technology Co., Ltd. Thermal initiators: bis(4-tert-butylphenyl)-iodonium tetraphenylborate (code: B1) and 4,4-di-tert-butyldiphenyliodonium hexafluorophosphate (code: B2) were from J&K; Other additives: surfactant BYK306 comes from BYK; 1-methoxy-2-propanol comes from Union Carbide Chemical; Protective layer materials: Polyvinyl alcohol PVA-205 comes from Kuraray Co., Ltd. of Japan; Polyvinyl pyrrolidone PVPK30 comes from BASF of Germany; Emulsifier OP-10 comes from Hamm, Germany.

[0060] Imaging layer raw materials (specific raw materials and amounts are shown in Table 1): Heat-sensitive component: The heat-sensitive component is based on the solid content of the emulsion, that is, the weight of the emulsion particles in the emulsion, excluding the solvent in the solution; Cross-linkable prepolymers; Thermal initiator; Infrared absorber IR830; The above raw materials were added with 0.5g of surfactant BYK306 and 700g of 1-methoxy-2-propanol to prepare an imaging layer coating solution. The imaging layer coating solution was extruded onto the hydrophilized substrate and dried at 100°C for 60 seconds to obtain 15mg / dm 2 dry weight of the coating.

[0061] The following protective layer may be extrusion coated on the imaging layer or not, and then dried at 110°C for 60 seconds. 2 dry weight of the coating.

[0062] Protective layer formula: Polyvinyl alcohol PVA-205 (Kuraray, Japan) 17g Polyvinylpyrrolidone PVPK30 (BASF, Germany) 3g Emulsifier OP-10 (Helm, Germany) 0.45g 480g deionized water Different thermal plates were prepared using the same process as above: the plate base, protective layer, solvent, and other necessary additives remained unchanged. The imaging layer formulation was modified according to the data in Table 1 to produce Examples 1-16 and Comparative Examples 1-8. Only Example 1 and Comparative Example 1 were coated with a protective layer; the remaining Examples were not. The properties of the thermal plates of these Examples and Comparative Examples are listed in Table 2.

[0063] Test and analysis of the plate material: All the thermal plate materials prepared above were placed in a standard thermal plate product packaging box. After being placed in an aging box at 40°C and 80% humidity for 24 hours, their performance was tested according to the following procedure.

[0064] 1. Sensitivity: On a Kodak Thermal CTP platesetter, 5 mJ / cm 2 The progressive amount is 80-200mJ / cm 2The plate was exposed within an energy range of 100 nm and the sensitivity of the plate was measured according to the Pantone LIVE color digital workflow. The performance is listed in Table 2 below.

[0065] 2. Dot Quality: Exposure was performed on a Kodak Trendsetter thermal CTP platesetter at optimal sensitivity. The image dot reproduction values ​​were measured according to the Pantone LIVE color digital workflow. The performance is listed in Table 2.

[0066] 3. On-press Development Performance (DOP): The printing plate was laser imaged on a Kodak Trendsetter thermal CTP platesetter and then mounted on a Roland R-201 press for on-press development. The fountain solution was DIC Graphics Presarto WS 100 / isopropyl alcohol / water (1 / 1 / 98, volume ratio). The rubber blanket was Kin-yo-sha S-7400. The paper was OK Top Coat Matte N Grade (Oji Paper). The ink was DIC Graphics Fusion G Magenta N. The printing speed was 9,000 sheets / hour. The number of printed sheets (unit: sheets) with no observed ink transfer in the unimaged area was used to characterize the DOP. The performance is listed in Table 2.

[0067] 4. Press life: Printing was performed on a Heidelberg-XL754C printing press. The total number of sheets of normal printed products produced by the thermal plate was tested. The performance is listed in Table 2 below.

[0068] The test application results in Table 2 show that, compared with the comparative example of the treatment-free plate, the treatment-free thermal plate produced by the treatment-free thermal plate precursor of the present invention has excellent imaging ability, on-press developing ability and printing run. This is because the hot-melt core-shell emulsion particles of the present invention contained in the treatment-free thermal plate precursor can achieve functional partitioning compared with traditional emulsion particles. The core layer copolymerization unit adopts a hard copolymerization unit, which is beneficial to improving the overall mechanical properties of the emulsion particles. Acrylonitrile has excellent solvent resistance and staining resistance, and can resist the solvent in the ink from penetrating into the core layer to cause the core to collapse. It can also resist the penetration of dyes and initiators. Avoid causing a decrease in initiation efficiency, the water-resistant reactive emulsifier can improve the ability to resist fountain solution erosion and improve ink affinity, the core layer does not contain double bonds to avoid causing polymerization shrinkage and affecting the accuracy of dot restoration; the shell copolymerization unit package adopts a soft copolymerization unit, which is conducive to improving the adhesion of the hot-melt core-shell emulsion particles, the hydrophilic reactive emulsifier can improve the on-machine development ability of the plate material, and at the same time, the oxetane copolymer component it contains has thermosensitive cross-linking, which can improve the thermal imaging performance of the plate material. The hot-melt core-shell emulsion particles provided by the present invention effectively solve the problem of the imaging ability, on-machine development ability and printing durability of the treatment-free thermal plate. The advantage of the protective layer is that it can protect the thermal layer, but it will cause the DOP to increase. Example 1 and Comparative Example 1 have a protective layer. Compared with the treatment-free thermal plate without a protective layer, the DOP will be relatively higher. Users can choose whether to have a protective layer for the treatment-free thermal plate according to their own operating environment.

[0069] Table 1 Material input for the imaging layer of the plates of the examples and comparative examples (unit: g) In Table 1, the heat-sensitive component is based on the solid content of the emulsion, that is, the weight of each emulsion particle in the emulsion, excluding the solvent in the solution. For example, in Example 1 in Table 1, the heat-sensitive component is the amount of the hot-melt core-shell emulsion particles D1 in the emulsion, which is 70 g.

[0070] Table 2 Plate application performance table The above description is only a preferred embodiment of the present invention, but the scope of protection 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 this 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 scope of protection of the present invention.

Claims

1. A hot-melt core-shell emulsion particle, characterized in that: The invention comprises a core layer and a shell layer. The raw materials corresponding to the core layer copolymerization unit include styrene, acrylonitrile and a water-resistant reactive emulsifier. The raw materials corresponding to the shell layer copolymerization unit include vinyl oxetane, butyl methacrylate and a hydrophilic reactive emulsifier.

2. The hot-melt core-shell emulsion particles according to claim 1, characterized in that: Vinyl oxetane has the following structure: Structure 1 R1 is methylene or carbonyl, R2 is methyl or hydrogen; The water-resistant reactive emulsifier is allyl fatty alcohol polyether ammonium sulfate, and its structure is as follows: Structure 2 R3 is a long-chain alkyl group with ≥12 C atoms or a long-chain alkylphenyl group with ≥9 C atoms; The hydrophilic reactive emulsifier is 2-acrylamido-2-methylpropanesulfonic acid.

3. The hot-melt core-shell emulsion particles according to claim 1, characterized in that: The weight ratio of styrene, acrylonitrile and water-resistant reactive emulsifier in the raw materials corresponding to the core copolymer units is: styrene: acrylonitrile: water-resistant reactive emulsifier is 30-40:10-20:3-6; the weight ratio of vinyl oxetane: butyl methacrylate: hydrophilic reactive emulsifier in the raw materials corresponding to the shell copolymer units is: vinyl oxetane: butyl methacrylate: hydrophilic reactive emulsifier is 10-20:30-40:5-10.

4. The method for preparing the hot-melt core-shell emulsion particles according to any one of claims 1 to 3, characterized in that: The step-by-step polymerization method of forming seed crystals → core layer polymerization → shell layer polymerization: first, take a part of the core layer pre-emulsion containing the raw materials corresponding to the core layer copolymerization unit, add it into deionized water with mechanical stirring and nitrogen protection, and heat it to react to form seed crystals, and then add the remaining core layer pre-emulsion containing the raw materials corresponding to the core layer copolymerization unit dropwise to react to form a core layer. After a certain reaction time, the shell layer pre-emulsion containing the raw materials corresponding to the shell layer copolymerization unit is added dropwise to continue the reaction. After the addition is completed, the reaction is continued for a certain time, and the temperature is lowered to terminate the reaction.

5. The method for preparing hot-melt core-shell emulsion particles according to claim 4, wherein: (1) Preparing a core layer pre-emulsion containing raw materials corresponding to the core layer copolymer units: stirring a mixture of styrene, acrylonitrile, a water-resistant reactive emulsifier, an initiator, and deionized water at 200-300 rpm and room temperature for at least 30 minutes to form a stable core layer pre-emulsion; (2) Preparing a shell pre-emulsion containing raw materials corresponding to the shell copolymer units: stirring a mixture of vinyl oxetane, butyl methacrylate, a hydrophilic reactive emulsifier, an initiator, and ionized water at room temperature for at least 30 minutes at 200-300 rpm to form a stable shell pre-emulsion; (3) At 200-300 rpm: add 3-5 parts of the core layer pre-emulsion to 160-240 parts of deionized water, and react at 70-80°C under nitrogen protection until the system changes from a transparent state to a turbid state instantly. Start timing. After reacting for 30-40 minutes, add the remaining core layer pre-emulsion dropwise within 2-3 hours. After the addition is complete, react for another 3-4 hours. Then, add the shell layer pre-emulsion dropwise within 3-4 hours. After the addition is complete, react for another 3-4 hours. Cool to room temperature to terminate the reaction.

6. The method for preparing hot-melt core-shell emulsion particles according to claim 5, wherein: The initiator is ammonium persulfate or azobisisobutyronitrile.

7. A process-free thermal plate precursor comprising a carrier and an imaging layer, characterized in that: The imaging layer comprises hot-melt core-shell emulsion particles, a cross-linkable prepolymer, a thermal initiator and an infrared absorber. The hot-melt core-shell emulsion particles are the hot-melt core-shell emulsion particles according to any one of claims 1 to 6.

8. The process-free heat-sensitive plate precursor according to claim 7, characterized in that: In the imaging layer, by weight percentage, the hot-melt core-shell emulsion particles account for 40-70% of the total solid content of the composition, the cross-linkable prepolymer accounts for 20-40% of the total solid content of the composition, the thermal initiator accounts for 5-13% of the total solid content of the composition, and the infrared absorber accounts for 3-10% of the total solid content of the composition.

9. The process-free heat-sensitive plate precursor according to claim 7, characterized in that: A protective layer is also provided on the imaging layer; The crosslinkable prepolymer is a crosslinkable prepolymer containing double bonds or epoxy bonds or a mixture thereof, or a crosslinkable prepolymer containing both double bonds and epoxy bonds; The thermal initiator is an iodonium salt; The infrared absorber is a cyanine dye with an absorption peak at 750-850 nm; The carrier is an aluminum plate that has been electrolytically roughened and anodized.

10. A treatment-free thermal plate, characterized in that: It is prepared from the processing-free heat-sensitive plate precursor described in any one of claims 7 to 9.

11. The use of the treatment-free thermal plate according to claim 10, characterized in that: The treatment-free thermal plate is scanned and exposed by a thermal CTP platemaking machine, and then washed and developed with water before being mounted on a printing press for printing or directly mounted on a printing press for development and printing with a printing press fountain solution.

Images