Treatment-free CTP plate coating and preparation method thereof

Abstract

The invention discloses a treatment-free CTP plate coating and a preparation method of the treatment-free CTP plate coating, and belongs to the technical field of printing plate coating materials. The photosensitive coating liquid is prepared from the following components in parts by weight: 70 to 80 parts of thermosensitive resin, 2 to 6 parts of infrared absorption dye, 1 to 5 parts of free radical initiator, 10 to 20 parts of hyperbranched siloxane containing active groups, 0.3 to 0.5 part of surfactant and 2 to 3 parts of water-soluble film-forming resin; the hyperbranched siloxane containing the active group is obtained by carrying out hydrolytic condensation reaction on gamma-methacryloxy propyl trimethoxy silane and gamma-glycidyl ether oxypropyl trimethoxy silane, the heat-sensitive resin is formed by polymerizing allyl polymeric monomers, and the structure of the heat-sensitive resin comprises an epoxy group. The treatment-free CTP plate coating has good pressrun, and the imaging capability of a plate material is improved by adding hyperbranched siloxane containing active groups.

Description

Technical Field

[0001] The invention belongs to the technical field of printing plate coating materials, and in particular relates to a treatment-free CTP plate coating and a preparation method thereof. Background Art

[0002] The processing-free CTP plate refers to a printing plate that can be directly used for printing in the computer direct platemaking process without the need for complex post-processing procedures such as chemical development. It records graphic information through physical and chemical changes in special photosensitive materials or heat-sensitive materials. After the processing-free CTP plate is exposed and imaged on the direct platemaking equipment, it can be printed on the machine without subsequent processing. It usually does not require chemical development, washing and other steps, and has the advantages of environmental protection and simplified workflow. Ordinary CTP plates need to go through chemical development, washing and other processing steps. Although they can also be directly printed on the machine, there are problems of environmental pollution and waste of resources. Therefore, the processing-free CTP plate has more advantages in environmental protection and ease of operation.

[0003] The treatment-free CTP plates include thermal, photosensitive and inkjet types, etc. For thermal-sensitive treatment-free CTP plates, infrared lasers are used to irradiate the plates, so that the thermal coating on the surface of the plates undergoes physical or chemical changes under the action of laser energy, so that certain components in the coating undergo cross-linking reactions, thereby forming oleophilic and hydrophilic regions, the oleophilic regions constitute the image and text parts, and the hydrophilic regions constitute the non-image and text parts. For photosensitive treatment-free CTP plates, light of a specific wavelength is used to irradiate the photosensitive materials on the surface of the plates to undergo photopolymerization and other reactions to form images and texts. In the application process, although the thermal phase change during imaging changes the affinity of the coating, the wear resistance is poor and the printing durability is low during the printing process. The patent application with publication number CN101397438A discloses a coating, preparation method and application of an aluminum plate substrate for inkjet printing direct platemaking. After the aluminum plate substrate used in the patent application is coated with the coating, the presence of nano-scale or micro-scale oxide particles in the coating makes the surface of the aluminum plate substrate have good wear resistance. However, due to the high specific surface energy of nano- or micron-sized oxide particles, they are in a thermodynamically unstable state and can easily reduce their surface energy by agglomeration. However, agglomeration will affect the uniformity and functionality of the material, making it difficult for the overall performance to meet the requirements. Summary of the invention

[0004] The object of the present invention is to provide a treatment-free CTP plate coating and a preparation method thereof, so as to solve the problem of low printing durability of the treated CTP plate coating.

[0005] A treatment-free CTP plate coating is formed after a photosensitive coating liquid is cured on a plate base, and the photosensitive coating liquid comprises the following components by weight: 70-80 parts of a heat-sensitive resin, 2-6 parts of an infrared absorbing dye, 1-5 parts of a free radical initiator, 10-20 parts of a hyperbranched siloxane containing an active group, 0.3-0.5 parts of a surfactant, and 2-3 parts of a water-soluble film-forming resin; the hyperbranched siloxane containing an active group is obtained by hydrolysis and condensation reaction of γ-methacryloxypropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane, and the active groups are methacryloxy and epoxy groups; the heat-sensitive resin is formed by polymerization of olefinic polymerization monomers, and the heat-sensitive resin comprises an epoxy group in its structure.

[0006] Furthermore, the heat-sensitive resin is prepared by the following steps:

[0007] Add vinyl polymerizable monomers into a solvent and mix, add an initiator to initiate a thermal polymerization reaction, and obtain a thermosensitive resin; the vinyl polymerizable monomers include 4-chloromethylstyrene, glycidyl methacrylate, and hydroxyethyl methacrylate.

[0008] Furthermore, the molar ratio of 4-chloromethylstyrene, glycidyl methacrylate and hydroxyethyl methacrylate is 1:5-6:3-4.

[0009] Further, the maximum absorption wavelength of the infrared absorbing dye is in the range of 700-1200nm;

[0010] The free radical initiator is one of an onium salt and a metallocene compound;

[0011] The water-soluble film-forming resin includes natural water-soluble polymers, semi-synthetic water-soluble polymers and synthetic water-soluble polymers.

[0012] Preferably, the infrared absorbing dye is one of cyanine dye, anthraquinone dye, phthalocyanine dye, quinoneimine dye and methine cyanine dye;

[0013] The free radical initiator is one of a diaryl iodonium salt and a triaryl sulfonium salt;

[0014] The water-soluble film-forming resin is one of carboxymethyl cellulose and polyvinyl alcohol.

[0015] Furthermore, the photosensitive coating liquid further comprises a diluent, and the mass proportion of the diluent in the photosensitive coating liquid is 85% to 90%;

[0016] The diluent includes at least one of alcohol, ketone, ester, ether, amide and aromatic solvents.

[0017] Preferably, the diluent is methyl ethyl ketone and 1-methoxy-2-propanol in a volume ratio of 2:7.

[0018] Furthermore, the molar ratio of the γ-methacryloxypropyltrimethoxysilane to the γ-glycidyloxypropyltrimethoxysilane is 1-1.5:1.

[0019] Furthermore, the hyperbranched siloxane containing active groups is prepared by the following steps:

[0020] γ-methacryloxypropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane are added to a 90% by volume aqueous ethanol solution, acetic acid is added to adjust the pH value to 3-5, and the mixture is stirred and reacted at 50-55° C. for 4 hours to obtain a hyperbranched siloxane containing active groups.

[0021] A method for preparing a treatment-free CTP plate coating, characterized in that it comprises the following steps:

[0022] The photosensitive coating liquid is coated on the plate base, and then exposed after drying to form exposed areas and unexposed areas. The unexposed areas are removed to obtain a processing-free CTP plate coating.

[0023] Beneficial effects of the present invention:

[0024] The treatment-free CTP plate coating prepared by the present invention has good printing durability. The imaging ability of the plate is improved by adding hyperbranched siloxane containing active groups. The introduced hyperbranched siloxane containing active groups can form a cationic cross-linking network with epoxy bonds on a photosensitive resin during exposure, which improves the wear resistance of the coating on the one hand. On the other hand, the introduced hyperbranched siloxane containing active groups has a hyperbranched structure and has a good adsorption effect on ink, which can further improve the printing efficiency. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Obviously, the following descriptions are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in the field related to the content disclosed in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient content disclosed in this application.

[0027] However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially the same structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the following description is provided for those skilled in the art to fully understand the present application and is not intended to limit the subject matter described in the claims.

[0028] If not otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution, and all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0029] The substrates in the examples and comparative examples of the present application were pre-treated before use, and the pre-treatment steps are as follows:

[0030] A 0.30 mm thick aluminum sheet was immersed in a 60°C aqueous solution containing 40 g / L NaOH for 8 seconds to remove oil stains, and then rinsed with demineralized water for 2 seconds. 2 The thin aluminum sheet was electrochemically roughened in an aqueous solution containing 12 g / L HCl and 38 g / L Al2(SO4)3 using alternating current at a current density of 1.5 A / dm to form a surface morphology with an average centerline roughness Ra of 0.5 μm. After rinsing with water for 2 seconds, it was etched with an aqueous solution containing 155 g / L sulfuric acid at 70°C for 4 seconds and then rinsed with water for 2 seconds. It was then heated at 45°C and 22 A / dm 2 The thin film was anodized in an aqueous solution containing 155g / L sulfuric acid at a current density of 2.90g / m 2 The A1203 anodized film was then washed with water for 2 seconds, treated with a solution containing 4 g / L polyvinylphosphonic acid at 40°C for 10 seconds, rinsed with water for 2 seconds, and then dried.

[0031] Preparation Example 1

[0032] The hyperbranched siloxane containing active groups is prepared by the following steps:

[0033] γ-Methacryloxypropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane were added to a 90% ethanol aqueous solution, acetic acid was added to adjust the pH value to 5, and the mixture was stirred at 50°C for 4 hours. After the reaction, the small molecules were removed by rotary evaporation at 50°C for 30 minutes to obtain a hyperbranched siloxane containing active groups. The molar ratio of γ-methacryloxypropyltrimethoxysilane to γ-glycidyloxypropyltrimethoxysilane was 1:1. The ratio of the amount of 90% ethanol aqueous solution to the total amount of γ-methacryloxypropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane was 5mL:2g.

[0034] Preparation Example 2

[0035] The hyperbranched siloxane containing active groups is prepared by the following steps:

[0036] γ-Methacryloxypropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane were added to a 90% ethanol aqueous solution, acetic acid was added to adjust the pH value to 5, and the mixture was stirred at 50°C for 4 hours. After the reaction, the small molecules were removed by rotary evaporation at 50°C for 30 minutes to obtain a hyperbranched siloxane containing active groups. The molar ratio of γ-methacryloxypropyltrimethoxysilane to γ-glycidyloxypropyltrimethoxysilane was 1.5:1. The amount of 90% ethanol aqueous solution and the total mass of γ-methacryloxypropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane were 5mL:2g.

[0037] Comparative Example Preparation Example 1

[0038] The hyperbranched siloxane containing active groups is prepared by the following steps:

[0039] γ-Methacryloxypropyltrimethoxysilane was added to a 90% ethanol aqueous solution, acetic acid was added to adjust the pH value to 5, and the mixture was stirred at 50°C for 4 hours. After the reaction, the small molecular substances were removed by rotary evaporation at 50-55°C for 30 minutes to obtain a hyperbranched siloxane containing active groups. The amount of 90% ethanol aqueous solution and the mass of γ-methacryloxypropyltrimethoxysilane were 5mL:2g.

[0040] Comparative Example Preparation Example 2

[0041] The hyperbranched siloxane containing active groups is prepared by the following steps:

[0042] γ-glycidyloxypropyltrimethoxysilane was added to a 90% ethanol aqueous solution, acetic acid was added to adjust the pH value to 5, and the mixture was stirred at 50°C for 4 hours. After the reaction, the small molecular substances were removed by rotary evaporation at 50-55°C for 30 minutes to obtain a hyperbranched siloxane containing active groups. The amount of the 90% ethanol aqueous solution and the total mass of γ-glycidyloxypropyltrimethoxysilane were 5 mL: 2 g.

[0043] Example 1

[0044] This embodiment provides a treatment-free CTP plate coating, wherein the coating is formed after a photosensitive coating liquid is cured on a plate substrate, wherein the photosensitive coating liquid comprises the following components in parts by weight: 70 parts of a heat-sensitive resin, 2 parts of IR-813 p-toluenesulfonate (CAS registration number 134127-48-3), 1 part of diphenyliodonium hexafluorophosphate, 10 parts of a hyperbranched siloxane containing an active group in Preparation Example 1, 0.3 parts of sodium dodecyl sulfate, and 2 parts of polyvinyl alcohol (PVA1788);

[0045] The thermosensitive resin is prepared by the following steps: adding 4-chloromethylstyrene, glycidyl methacrylate and hydroxyethyl methacrylate in a molar ratio of 1:5.5:3.5 to methyl ethyl ketone and mixing, adding 1% of the total weight of the monomer as an initiator azobisisobutyronitrile for polymerization reaction, reacting at a temperature of 70°C for 8 hours to obtain a thermosensitive resin.

[0046] The method for preparing the treatment-free CTP plate coating comprises the following steps:

[0047] The components of the photosensitive coating liquid were weighed according to the formula, diluted with a diluent and coated on the substrate. The diluent was methyl ethyl ketone and 1-methoxy-2-propanol in a volume ratio of 2:7, and the diluent accounted for 85%. Drying (drying at 100°C for 1 min; the coating dry weight was 8 mg / dm 2 ) is then exposed to form exposed areas and unexposed areas, and the unexposed areas are removed by a development process.

[0048] Example 2

[0049] The present embodiment provides a treatment-free CTP plate coating, wherein the coating is formed after a photosensitive coating liquid is cured on a plate substrate, wherein the photosensitive coating liquid comprises the following components in parts by weight: 70 parts of a heat-sensitive resin, 2 parts of IR-813 p-toluenesulfonate (CAS registration number 134127-48-3), 1 part of diphenyliodonium hexafluorophosphate, 10 parts of a hyperbranched siloxane containing an active group in Preparation Example 2, 0.3 parts of sodium dodecyl sulfate, and 2 parts of polyvinyl alcohol (PVA1788);

[0050] The thermosensitive resin is prepared by the following steps: adding 4-chloromethylstyrene, glycidyl methacrylate and hydroxyethyl methacrylate in a molar ratio of 1:5.5:3.5 to methyl ethyl ketone and mixing, adding 1% of the total weight of the monomer as an initiator azobisisobutyronitrile for polymerization reaction, reacting at a temperature of 70°C for 8 hours to obtain a thermosensitive resin.

[0051] The method for preparing the treatment-free CTP plate coating comprises the following steps:

[0052] The components of the photosensitive coating liquid were weighed according to the formula, diluted with a diluent and coated on the substrate. The diluent was methyl ethyl ketone and 1-methoxy-2-propanol in a volume ratio of 2:7, and the diluent accounted for 85%. Drying (drying at 100°C for 1 min; the coating dry weight was 8 mg / dm 2 ) is then exposed to form exposed areas and unexposed areas, and the unexposed areas are removed by a development process.

[0053] Example 3

[0054] This embodiment provides a treatment-free CTP plate coating, wherein the coating is formed after a photosensitive coating liquid is cured on a plate substrate, wherein the photosensitive coating liquid comprises the following components in parts by weight: 80 parts of a heat-sensitive resin, 6 parts of IR-813 p-toluenesulfonate (CAS registration number 134127-48-3), 5 parts of diphenyliodonium hexafluorophosphate, 20 parts of a hyperbranched siloxane containing an active group in Preparation Example 1, 0.5 parts of sodium dodecyl sulfate, and 3 parts of polyvinyl alcohol (PVA1788);

[0055] The thermosensitive resin is prepared by the following steps: adding 4-chloromethylstyrene, glycidyl methacrylate and hydroxyethyl methacrylate in a molar ratio of 1:5.5:3.5 to methyl ethyl ketone and mixing, adding 1% of the total weight of the monomer as an initiator azobisisobutyronitrile for polymerization reaction, reacting at a temperature of 70°C for 8 hours to obtain a thermosensitive resin.

[0056] The method for preparing the treatment-free CTP plate coating comprises the following steps:

[0057] The components of the photosensitive coating liquid were weighed according to the formula, diluted with a diluent and coated on the substrate. The diluent was methyl ethyl ketone and 1-methoxy-2-propanol in a volume ratio of 2:7, and the diluent accounted for 85%. Drying (drying at 100°C for 1 min; the coating dry weight was 8 mg / dm 2 ) is then exposed to form exposed areas and unexposed areas, and the unexposed areas are removed by a development process.

[0058] Example 4

[0059] This embodiment provides a treatment-free CTP plate coating, wherein the coating is formed after a photosensitive coating liquid is cured on a plate substrate, wherein the photosensitive coating liquid comprises the following components in parts by weight: 80 parts of a heat-sensitive resin, 6 parts of IR-813 p-toluenesulfonate (CAS registration number 134127-48-3), 5 parts of diphenyliodonium hexafluorophosphate, 20 parts of a hyperbranched siloxane containing an active group in Preparation Example 2, 0.5 parts of sodium dodecyl sulfate, and 3 parts of polyvinyl alcohol (PVA1788);

[0060] The thermosensitive resin is prepared by the following steps: adding 4-chloromethylstyrene, glycidyl methacrylate and hydroxyethyl methacrylate in a molar ratio of 1:5.5:3.5 to methyl ethyl ketone and mixing, adding 1% of the total weight of the monomer as an initiator azobisisobutyronitrile for polymerization reaction, reacting at a temperature of 70°C for 8 hours to obtain a thermosensitive resin.

[0061] The method for preparing the treatment-free CTP plate coating comprises the following steps:

[0062] The components of the photosensitive coating liquid were weighed according to the formula, diluted with a diluent and coated on the substrate. The diluent was methyl ethyl ketone and 1-methoxy-2-propanol in a volume ratio of 2:7, and the diluent accounted for 85%. Drying (drying at 100°C for 1 min; the coating dry weight was 8 mg / dm 2 ) is then exposed to form exposed areas and unexposed areas, and the unexposed areas are removed by water development in a development process.

[0063] Example 5

[0064] This embodiment provides a treatment-free CTP plate coating, wherein the coating is formed after a photosensitive coating liquid is cured on a plate substrate, wherein the photosensitive coating liquid comprises the following components in parts by weight: 70 parts of a heat-sensitive resin, 2 parts of IR-813 p-toluenesulfonate (CAS registration number 134127-48-3), 1 part of diphenyliodonium hexafluorophosphate, 10 parts of a hyperbranched siloxane containing an active group in Preparation Example 1, 0.3 parts of sodium dodecyl sulfate, and 2 parts of polyvinyl alcohol (PVA1788);

[0065] The thermosensitive resin is prepared by the following steps: adding 4-chloromethylstyrene, glycidyl methacrylate and hydroxyethyl methacrylate in a molar ratio of 1:5:4 to methyl ethyl ketone and mixing, adding 1% of the total weight of the monomer as an initiator azobisisobutyronitrile for polymerization reaction, reacting at a temperature of 70°C for 8 hours to obtain the thermosensitive resin.

[0066] The method for preparing the treatment-free CTP plate coating comprises the following steps:

[0067] The components of the photosensitive coating liquid were weighed according to the formula, diluted with a diluent and coated on the substrate. The diluent was methyl ethyl ketone and 1-methoxy-2-propanol in a volume ratio of 2:7, and the diluent accounted for 85%. Drying (drying at 100°C for 1 min; the coating dry weight was 8 mg / dm 2 ) is then exposed to form exposed areas and unexposed areas, and the unexposed areas are removed by a development process.

[0068] Example 6

[0069] This embodiment provides a treatment-free CTP plate coating, wherein the coating is formed after a photosensitive coating liquid is cured on a plate substrate, wherein the photosensitive coating liquid comprises the following components in parts by weight: 70 parts of a heat-sensitive resin, 2 parts of IR-813 p-toluenesulfonate (CAS registration number 134127-48-3), 1 part of diphenyliodonium hexafluorophosphate, 10 parts of a hyperbranched siloxane containing an active group in Preparation Example 1, 0.3 parts of sodium dodecyl sulfate, and 2 parts of polyvinyl alcohol (PVA1788);

[0070] The thermosensitive resin is prepared by the following steps: adding 4-chloromethylstyrene, glycidyl methacrylate and hydroxyethyl methacrylate in a molar ratio of 1:6:3 to methyl ethyl ketone and mixing, adding 1% of the total weight of the monomer as an initiator azobisisobutyronitrile for polymerization reaction, reacting at a temperature of 70°C for 8 hours to obtain the thermosensitive resin.

[0071] The method for preparing the treatment-free CTP plate coating comprises the following steps:

[0072] The components of the photosensitive coating liquid were weighed according to the formula, diluted with a diluent and coated on the substrate. The diluent was methyl ethyl ketone and 1-methoxy-2-propanol in a volume ratio of 2:7, and the diluent accounted for 85%. Drying (drying at 100°C for 1 min; the coating dry weight was 8 mg / dm 2 ) is then exposed to form exposed areas and unexposed areas, and the unexposed areas are removed by a development process.

[0073] Example 7

[0074] This embodiment provides a treatment-free CTP plate coating, wherein the coating is formed after a photosensitive coating liquid is cured on a plate substrate, wherein the photosensitive coating liquid comprises the following components in parts by weight: 80 parts of a heat-sensitive resin, 6 parts of IR-813 p-toluenesulfonate (CAS registration number 134127-48-3), 5 parts of diphenyliodonium hexafluorophosphate, 20 parts of a hyperbranched siloxane containing an active group in Preparation Example 1, 0.5 parts of sodium dodecyl sulfate, and 3 parts of polyvinyl alcohol (PVA1788);

[0075] The thermosensitive resin is prepared by the following steps: adding 4-chloromethylstyrene, glycidyl methacrylate and hydroxyethyl methacrylate in a molar ratio of 1:5:4 to methyl ethyl ketone and mixing, adding 1% of the total weight of the monomer as an initiator azobisisobutyronitrile for polymerization reaction, reacting at a temperature of 70°C for 8 hours to obtain the thermosensitive resin.

[0076] The method for preparing the treatment-free CTP plate coating comprises the following steps:

[0077] The components of the photosensitive coating liquid were weighed according to the formula, diluted with a diluent and coated on the substrate. The diluent was methyl ethyl ketone and 1-methoxy-2-propanol in a volume ratio of 2:7, and the diluent accounted for 85%. Drying (drying at 100°C for 1 min; the coating dry weight was 8 g / dm 2 ) is then exposed to form exposed areas and unexposed areas, and the unexposed areas are removed by a development process.

[0078] Example 8

[0079] This embodiment provides a treatment-free CTP plate coating, wherein the coating is formed after a photosensitive coating liquid is cured on a plate substrate, wherein the photosensitive coating liquid comprises the following components in parts by weight: 80 parts of a heat-sensitive resin, 6 parts of IR-813 p-toluenesulfonate (CAS registration number 134127-48-3), 5 parts of diphenyliodonium hexafluorophosphate, 20 parts of a hyperbranched siloxane containing an active group in Preparation Example 1, 0.5 parts of sodium dodecyl sulfate, and 3 parts of polyvinyl alcohol (PVA1788);

[0080] The thermosensitive resin is prepared by the following steps: adding 4-chloromethylstyrene, glycidyl methacrylate and hydroxyethyl methacrylate in a molar ratio of 1:6:3 to methyl ethyl ketone and mixing, adding 1% of the total weight of the monomer as an initiator azobisisobutyronitrile for polymerization reaction, reacting at a temperature of 70°C for 8 hours to obtain the thermosensitive resin.

[0081] The method for preparing the treatment-free CTP plate coating comprises the following steps:

[0082] The components of the photosensitive coating liquid were weighed according to the formula, diluted with a diluent and coated on the substrate. The diluent was methyl ethyl ketone and 1-methoxy-2-propanol in a volume ratio of 2:7, and the diluent accounted for 85%. Drying (drying at 100°C for 1 min; the coating dry weight was 8 g / dm 2 ) and then exposed at 120 mJ / cm 2 The material is exposed by energy of , forming exposed areas and unexposed areas, and the unexposed areas are removed by a development process.

[0083] Comparative Example 1

[0084] Compared with Example 1, the hyperbranched siloxane containing active groups in this comparative example is replaced with the hyperbranched siloxane containing active groups prepared in Comparative Example Preparation Example 1, and the other raw materials and preparation method are the same as those in Example 1.

[0085] Comparative Example 2

[0086] Compared with Example 1, the hyperbranched siloxane containing active groups in this comparative example is replaced with the hyperbranched siloxane containing active groups prepared in Comparative Example Preparation Example 2, and the other raw materials and preparation method remain the same as those in Example 1.

[0087] Comparative Example 3

[0088] Compared with Example 1, in this comparative example, no hyperbranched siloxane containing active groups is added, and the remaining raw materials and preparation methods are the same as those in Example 1.

[0089] Performance tests were conducted on Examples 1 to 8 and Comparative Examples 1 to 3: Printing durability test: The above-mentioned plate samples were put into normal printing on a machine (Beiren four-color four-page high-speed rotary printing press), the printing press was turned on and the entire plate surface was moistened with fountain solution for 20 seconds, then the ink roller was closed and run for 5 seconds, and then paper was supplied to start printing.

[0090] The results are shown in Table 1:

[0091] Table 1

[0092]

[0093]

[0094] As can be seen from Table 1, the paper prepared by the present invention has good press run, the prepared hyperbranched siloxane containing active groups can increase the wear resistance of the plate, the hyperbranched siloxane containing active groups and the photosensitive resin both contain highly active groups (not only have free radical polymerization imaging ability, but also have epoxy bonds that can undergo cationic network crosslinking), which can achieve network imaging, especially the hyperbranched structure in the hyperbranched siloxane containing active groups can greatly improve the press run of the plate.

[0095] The number of overprinted papers refers to the number of papers used to adjust the parameters such as ink-water balance and pressure of the printing press before formal printing in the offset printing production process. These papers may be wasted during the adjustment process because they are usually unable to become qualified printed products. The fewer the number of overprinted papers, the fewer the wasted papers, which helps to reduce printing costs. The number of overprinted papers of the sample prepared by the present invention is small, and the reason is that the hyperbranched structure in the hyperbranched siloxane containing active groups can increase the adsorption effect on ink, reduce the interfacial tension between ink and substrate, increase the contact area between ink and substrate, and improve the rheological properties of ink. This helps to reduce the waste of ink in the printing process, because the ink can be more effectively transferred to the substrate, reducing the use of overprinted paper. And the hyperbranched structure can reduce the time required for the printing press to adjust the ink-water balance by improving the adsorption effect of ink on the layout, because the ink can adapt to the printing conditions faster, improve the adhesion of ink to the substrate, can improve the printing quality, reduce the reprinting caused by the printing quality problem, and then reduce the use of overprinted paper.

[0096] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0097] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A treatment-free CTP plate coating, characterized in that: The coating is formed after a photosensitive coating liquid is cured on a substrate, and the photosensitive coating liquid comprises the following components in parts by weight: 70-80 parts of a heat-sensitive resin, 2-6 parts of an infrared absorbing dye, 1-5 parts of a free radical initiator, 10-20 parts of a hyperbranched siloxane containing an active group, 0.3-0.5 parts of a surfactant, and 2-3 parts of a water-soluble film-forming resin; the hyperbranched siloxane containing an active group is obtained by hydrolysis and condensation reaction of γ-methacryloxypropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane, and the active groups are methacryloxy and epoxy groups; the heat-sensitive resin is formed by polymerization of olefinic polymerization monomers, and the structure of the heat-sensitive resin comprises an epoxy group.

2. A treatment-free CTP plate coating according to claim 1, characterized in that: The heat-sensitive resin is prepared by the following steps: Add vinyl polymerizable monomers into a solvent and mix, add an initiator to initiate a thermal polymerization reaction, and obtain a thermosensitive resin; the vinyl polymerizable monomers include 4-chloromethylstyrene, glycidyl methacrylate, and hydroxyethyl methacrylate.

3. A treatment-free CTP plate coating according to claim 2, characterized in that: The molar ratio of the 4-chloromethylstyrene, glycidyl methacrylate and hydroxyethyl methacrylate is 1:5-6:3-4.

4. The treatment-free CTP plate coating according to claim 1, characterized in that: The maximum absorption wavelength of the infrared absorbing dye is in the range of 700-1200nm; The free radical initiator is one of an onium salt and a metallocene compound; The water-soluble film-forming resin includes natural water-soluble polymers, semi-synthetic water-soluble polymers and synthetic water-soluble polymers.

5. The treatment-free CTP plate coating according to claim 1, characterized in that: The infrared absorbing dye is one of cyanine dye, anthraquinone dye, phthalocyanine dye, quinoneimine dye and methine cyanine dye; The free radical initiator is one of a diaryl iodonium salt and a triaryl sulfonium salt; The water-soluble film-forming resin is one of carboxymethyl cellulose and polyvinyl alcohol.

6. The treatment-free CTP plate coating according to claim 1, characterized in that: The photosensitive coating liquid further includes a diluent, and the mass proportion of the diluent in the photosensitive coating liquid is 85% to 90%; The diluent includes at least one of alcohol, ketone, ester, ether, amide and aromatic solvents.

7. The treatment-free CTP plate coating according to claim 6, characterized in that: The diluent is methyl ethyl ketone and 1-methoxy-2-propanol in a volume ratio of 2:

7.

8. The treatment-free CTP plate coating according to claim 1, characterized in that: The molar ratio of the γ-methacryloxypropyltrimethoxysilane to the γ-glycidyloxypropyltrimethoxysilane is 1-1.5:

1.

9. The treatment-free CTP plate coating according to claim 1, characterized in that: The hyperbranched siloxane containing active groups is prepared by the following steps: γ-methacryloxypropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane are added to an ethanol aqueous solution, the pH value is adjusted to 3-5, and the mixture is stirred and reacted at 50-55° C. for 4 hours to obtain a hyperbranched siloxane containing an active group.

10. A method for preparing a treatment-free CTP plate coating according to any one of claims 1 to 9, characterized in that: The steps include: The photosensitive coating liquid is coated on the plate base, and after drying, it is exposed to form exposed areas and unexposed areas. The unexposed areas are removed to obtain a processing-free CTP plate coating.

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