CN108297565B

CN108297565B - On-machine development treatment-free thermosensitive plate with nano-micron structure protective layer

Info

Publication number: CN108297565B
Application number: CN201610750332.0A
Authority: CN
Inventors: 宋小伟; 张涛; 高英新; 高峰; 马天如; 刘松玲; 张攀; 李喜乐
Original assignee: Beijing Aerospace Innovation Patent Investment Center LP; Lucky Huaguang Graphics Co Ltd
Current assignee: Beijing Aerospace Innovation Patent Investment Center LP; Lucky Huaguang Graphics Co Ltd
Priority date: 2016-08-27
Filing date: 2016-08-27
Publication date: 2020-10-27
Anticipated expiration: 2036-08-27
Also published as: CN108297565A

Abstract

The invention relates to an on-press development treatment-free thermosensitive plate with a nano-micron structure protective layer, which comprises an aluminum plate base supporting body, a coating layer containing a negative photosensitive composition and the protective layer with the nano-micron structure, wherein the aluminum plate base supporting body, the coating layer and the protective layer are distributed from bottom to top. The aluminum plate base supporting body is subjected to electrolytic coarsening, anodic oxidation and hole sealing treatment, and the average thickness of a central line is 0.4-0.6 mu m; the negative photosensitive composition mainly contains discrete nano-micron particles, a diurea ketone prepolymer, a polyfunctional monomer, a thermal polymerization initiator and an infrared absorbent; the particle size of discrete nano-micron particles in the nano-micron structure protective layer is 50-150 nm. The invention adopts the hydrophilic but water-insoluble protective layer with the nano-micron structure, solves the problems that the protective layer pollutes fountain solution and the permeability of the film is poor at normal temperature, improves the on-machine developing capability of the plate material, greatly reduces the number of paper passing the plate, can directly print on a machine, can obtain high pressrun and realizes green and environment-friendly printing.

Description

On-machine development treatment-free thermosensitive plate with nano-micron structure protective layer

Technical Field

The invention belongs to the technical field of lithographic printing, and particularly relates to an on-press development treatment-free thermosensitive plate with a nano-micron structure protective layer.

Background

The lithographic printing technology has been completely moved from the traditional PS plate copying technology of laser photo film to the computer-to-plate technology (CTP technology for short), and CTP plates are gradually popularized. The CTP plates are various in types and include silver salt diffusion CTP plates, UV-CTP plates, violet laser polymerization CTP plates, thermosensitive CTP plates and the like which are more popular. Among them, the most widely used is the thermosensitive CTP plate.

The CTP plate making technology needs a 'developing process', and has the environmental problem caused by waste liquid treatment. At present, the development of a new generation of green and environment-friendly CTP plate free of chemical treatment is a hotspot for the development of plate materials in the world.

The development of green and environment-friendly chemical treatment-free CTP plates has many technical routes, which can be divided into a thermal ablation technology, a polarity conversion technology and a hot melting technology. The thermal ablation technology plate adopts an aluminum plate base or a polyester base, and utilizes a plasma metal deposition technology to prepare the plate. But ablation plates present a residue problem. Presstek company has published ablative plates with a sandwich structure to solve the ablation residue problem. Eka corporation developed an ablative technique of untreated CTP plates with a silver deposit, consisting of a support with a hydrophilic surface (aluminum, PET), a metal deposit that can be ablated and a cross-linked hydrophobic layer. The metal deposition layer is a metal film formed by using a metal deposition technique, and the metal may be silver, titanium, or the like. The crosslinked hydrophobic layer is crosslinked by irradiation or heat curing to crosslink the unsaturated monomer, and may be crosslinked by a heat-sensitive resin to form a cured layer, or may be obtained by treatment with a lipid-sensitive liquid. The infrared laser energy causes the silver particles in the silver layer to change in surface tension to form fluffy silver particles which remain on the surface of the plate, so that the residues are easily removed by vacuum adsorption or liquid to expose the hydrophilic surface of the aluminum plate to form hydrophilic areas, while the unexposed crosslinked layer is insoluble in the liquid to form lipophilic areas.

Polarity conversion technology: the plate material consists of a supporting body and a thermosensitive imaging layer. The thermosensitive imaging layer contains photothermal transducer and thermosensitive switchable polymer (such as polytetrahydropyran methacrylate, ethylene copolymer with aryldiazosulfonic acid group). A heat sensitive switchable polymer is used to form the heat sensitive material. Before imaging, the thermosensitive layer is dissolved in an aqueous solution. During imaging, the infrared absorber absorbs laser energy, and the generated heat causes diazo decomposition, so that the exposed thermosensitive copolymer is changed from hydrophilic to hydrophobic, and a lipophilic area is formed. While the thermosensitive copolymer remains soluble in water in the unexposed areas, forming hydrophilic areas. The factors that restrict this technology development are still printability. The ink and wash part is coated with a medicine film, so that the printing control and the printing resistance are greatly restricted, and the large-scale commercial application is realized.

Hot melting technology: is a technology really applied to commercialization in the third generation treatment-free plate at present. In thermal imaging, the infrared absorber converts laser energy into heat energy, the generated heat makes the temperature of thermoplastic polymer particles dispersed in the crosslinking hydrophilic layer higher than the gel humidity thereof, the thermoplastic polymer particles are subjected to agglutination reaction, and the exposed area is changed from hydrophilicity to hydrophobicity and lipophilicity. And the unexposed area is still dissolved in the aqueous solution with the PH being more than or equal to 4 to form a hydrophilic area. The blank part of the printing plate is an aluminum base after frosting and oxidation treatment, but not a medicine film coating, and the printability of the printing plate is not different from that of a common plate.

One of the key technologies for developing a chemical treatment-free CTP plate is the development of a plate precursor, namely a functional organic substance. EP0980754 describes a technique for realizing hydrophilic-hydrophobic transformation by carboxyl decarboxylation, but the molecular weight of a phase-transition compound is too large, the energy threshold value is large, and the decarboxylation is difficult, so that the printing plate material has poor printing resistance. WO94/23954 describes a microcapsule hot melting technique, wherein laser hot melting destroys microcapsules, hydrophilic substances are destroyed and turned into hydrophobic substances, but the damaged substances easily cause pollution to printing blanks; US4004924 describes a mixture of thermoplastic hydrophobic particles and a hydrophilic binder, but is not print-resistant; aikfa EP 2006-5-2406114475.4 introduces a semi-continuous emulsion method for preparing styrene and acrylonitrile emulsion thermoplastic particles, which can realize hot melting, but does not contain self-emulsifying hydrophilic groups, has high technical requirements on particle control, has poor stability of emulsified emulsion, and needs to be added with an anti-microbial agent; kodak US 2005-8-311/196, 124 describes an adhesive comprising a polyalkylene oxide segment and a hydrophobic cyano pendant group polymeric, the molecules being one-dimensional linear in structure and not highly resistant to indentation; kodak US 2006-7-2711/494, 235 describes a solvent-resistant polymer containing hydrophilic and cyano side groups, containing allyl ester branches, which are formed by condensation of carboxyl side groups and allyl halides under the action of a base, but with a large number of side reaction by-products, troublesome work-up and also the ester groups are not print-resistant.

At present, further improving the performance of the treatment-free thermosensitive CTP plate, particularly improving the printing resistance of the plate material is a hot spot for developing the thermosensitive CTP plate material.

To improve the printing resistance of the plate material of the treatment-free thermosensitive CTP plate, the solvent resistance of the plate material needs to be improved. By plate resistant to solvents is meant that the printing plate is resistant to attack by organic solvents in various printing chemicals, such as washing oils, fountain solutions, gum solutions, plate preservers, plate cleaners, printing inks, especially UV ink washing oils, used in printing.

The CTP plate printing plate has a certain correlation between the printing resistance and the solvent resistance, and generally, a plate with better solvent resistance has higher wear resistance and can obtain higher printing resistance.

Many methods are used for improving the solvent resistance and printing resistance of the thermosensitive CTP plate, and one of the most important methods is the development of organic matters of the printing plate, particularly functional film-forming resins. According to the disclosure of Shimazu patent US 6294311: carboxyl acrylic resin, vinyl acetate/crotonate (trans-butenoate)/vinyl neodecanoate copolymer, styrene maleic anhydride copolymer, phenolic resin, maleated wood rosin and the composition thereof have solvent resistance, and particularly, N-substituted maleimide, methacrylamide and polyvinyl acetal polymers can improve the printing process of a printing plate; kodak patent CN101321632A discloses that a phosphoric acid or adamantane side group is introduced into a polymer to improve the chemical resistance and the pressrun of a printing plate; WO2004/033206 by Kodak company proposes that barbituric acid groups are introduced into the side chains of high polymer resin, so that the solvent resistance and the wear resistance of a plate coating can be obviously improved, and the printing resistance of the plate is improved; kodak in WO2004/033206 discloses a QHB modified phenolic resin, which is modified with isocytosine (2-amino-4-hydroxypyrimidine) and isocyanate to form a strong polar tetrahydrobonded structure, and is used as an upper layer of a multi-layer thermosensitive plate, i.e., a second polymerization layer, to improve the wear resistance of the plate; in kodak patent US2006, 045648 a solvent resistant plate is disclosed containing an anhydride based polymer, the most useful anhydride groups disclosed being maleic anhydride and its derivatives; ackshire EP 31 02102446.8 discloses a modification method for diazo salt grafting of phenolic resin by phenolic hydroxyl telechelic group to form azo-aryl group (-N-Q group, Q is aromatic group), which improves chemical resistance of coating and printing plate resistance; fuji film [32]2004.3.11[33] JP [31]2004-069478 proposes that thermosensitive plate resin with a main chain having a phenol skeleton and a urea bond (-NHCONH-) has solvent resistance, so that the printing resistance of the printing plate material is improved; in EP- ｃA-1101607, ｃA heat-sensitive plate technique is disclosed, in which ｃA solvent-resistant technique is described, in which ｃA coating of the plate, to which an acidic cellulose polymer is added, improves the solvent resistance of the coating of the plate, and which is resistant to attack by ink and fountain solution on the film of the plate and has excellent resistance to printing.

The method for improving the printing capability of the thermosensitive CTP plate is realized by developing organic matters of the printing plate, particularly functional film-forming resin.

It is well known that the polymer resin is divided into a linear structure and a network structure, and generally, the linear structure resin can be dissolved in a solvent, while the network structure polymer resin is generally swollen by the solvent and can not be dissolved by the solvent. Therefore, the reticular polymer resin has better wear resistance.

The process for producing the treatment-free thermosensitive CTP plate generally comprises the step of coating a thermosensitive composition on a support such as an aluminum plate base in a form of solution by means of dip coating, spray coating or extrusion coating, so that the situation that a reticular structure polymer resin which is difficult to dissolve is added into the thermosensitive composition to obtain better wear resistance so as to improve the printing resistance of the plate material is difficult to realize.

In view of the above problems, our patent application CN 104730862A: the negative photosensitive composition and the thermosensitive plate made of the composition are designed into a treatment-free thermosensitive CTP plate negative photosensitive composition and the thermosensitive plate made of the composition. The negative photosensitive composition comprises discrete nano-micron particles, a diurea ketone prepolymer, a multifunctional monomer, a thermal polymerization initiator, an infrared absorbent and an organic metal promoter. The plate material has a brand new multiple thermal-sensitive imaging mechanism, can realize the hot melting thermoplasticity of nano-micron particles, the free baseline thermal polymerization and the reticulated thermal crosslinking of polyurethane, and has the advantages of high light sensitivity, good mesh reducibility and high pressrun due to the multiple thermal-sensitive imaging mechanism. After infrared laser scanning imaging is carried out, the oil-in-water structure is changed into oleophylic by the hot melting and thermoplastic destruction of nano-micro particles, and meanwhile, the molecular weight of a coating is rapidly increased by free-base linear thermal polymerization and the reticular thermal crosslinking of polyurethane, so that the coating is firmer, and the coating after laser thermal exposure is difficult to remove by fountain water and printing ink; and removing the redundant coating of the unexposed blank part on a printing machine under the action of dampening water and printing ink, and carrying away the redundant coating by the printing paper after removing the redundant coating, wherein the blank part is a hydrophilic aluminum plate base. The strong polar urethane bond net-shaped cross-linked structure enables the plate material to obtain ultrahigh printing resistance. The method can be used for direct machine printing without any washing processing step, can obtain high printing resistance, and realizes the environmental protection purpose of no pollutant discharge in the plate making process.

Our patent application CN 104730862A: the negative image photosensitive composition and the thermosensitive plate made of the composition have not solved a problem, and the protective layer causes the problems of polluting fountain solution and reducing on-press developing capability: the water-soluble polymer used as the material of the protective layer, such as polyvinyl alcohol, is dissolved and accumulated for a long time, pollutes fountain solution, and in addition, the normal temperature permeability of the protective layer material after film forming is poor, so that the protective layer material is difficult to remove under the action of fountain solution and ink, the number of paper passing through the plate is increased rapidly, and paper is wasted.

Disclosure of Invention

The object of the present invention is to provide a method for CN 104730862A: the invention adopts the hydrophilic but water-insoluble protective layer with a nano-micron structure, solves the problems of the pollution of the protective layer to fountain solution and poor permeability of the film at normal temperature, improves the on-machine development capability of the plate, greatly reduces the number of paper passing through the plate, can be directly printed on a machine, can obtain high printing resistance and realizes green and environment-friendly printing.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the invention provides an on-press development treatment-free thermosensitive plate with a nano-micron structure protective layer, which comprises an aluminum plate base support, a coating layer containing a negative photosensitive composition and the protective layer with the nano-micron structure, wherein the aluminum plate base support is distributed from bottom to top.

According to the on-press development treatment-free thermosensitive plate with the nano-micron structure protective layer, the negative photosensitive composition mainly comprises, by weight, 40-60% of discrete nano-micron particles, 20-40% of diurea ketone prepolymer, 10-20% of polyfunctional monomer, 5-15% of thermal polymerization initiator, 5-15% of infrared absorbent and 1-3% of organic metal accelerator, wherein the discrete nano-micron particles account for the total solid amount of the negative photosensitive composition.

The on-press development treatment-free thermosensitive plate with the protective layer with the nano-micron structure has the following structure, wherein the particle size of the discrete nano-micron particles is 50-300nm, and the weight-average molecular weight is 40000-10000:

R₁、R₂、R₄is H atom or methyl group, R₃Is CH₂CH₂OH or CH₂CH₂CH₂OH,R₅Is COO (CH)₂CH₂)_nH or COOCH₂CH₂NHCOO(CH₂CH₂)_nH, n is an integer of 20-60;

a. b, c and d are the weight percentage of the corresponding copolymerization units, the proportion of a is 40-70%, the proportion of b is 10-30%, the proportion of c is 10-30%, and the proportion of d is 10-30%.

The on-press development treatment-free thermosensitive plate with the nano-micron structure protective layer is characterized in that the diurea ketone prepolymer has the following structure:

wherein R is:

the multifunctional monomer is a multifunctional acrylic monomer.

The thermal polymerization initiator is a halogen substituted triazine compound, and the thermal decomposition temperature of the thermal polymerization initiator is 150-200 ℃.

The infrared absorbent is a cyanine dye with an absorption peak at 750-850 nm.

The organometallic promoter is an organometallic tin.

The protective layer with the nano-micron structure comprises the particles with the particle size of 50-150nm in the discrete nano-micron particles.

The aluminum plate base supporting body is subjected to electrolytic coarsening, anodic oxidation and hole sealing treatment, and the average thickness of the central line is 0.4-0.6 mu m.

The dry weight of the coating layer containing the negative photosensitive composition is 8-15mg/dm²。

The dry weight of the protective layer with the nano-micron structure is 5-20mg/dm²。

The planographic plate can be directly mounted on a printing machine for printing without any processing step after being scanned and exposed by using a thermosensitive CTP plate making machine.

The following is a detailed description of the invention.

The heat-sensitive support comprises a paper substrate, a polyester substrate, a rubber substrate and a composite materialSubstrate, and metal substrates such as copper substrates, aluminum substrates, and the like. The heat-sensitive plate support is an aluminum plate base support, and the aluminum plate base is processed by a special process. The aluminum plate base treatment process comprises the following steps: the plate base used by the invention is an aluminum plate base subjected to electrolytic coarsening, anodic oxidation and hole sealing treatment, and the average thickness of the central line is 0.4-0.6u m. Such a substrate can be produced by various electrolytic roughening methods. The aluminum plate base of the invention is a high-purity aluminum plate, and the aluminum content is preferably more than 99%. Suitable aluminum plate bases are (but not limited to): 0.1-0.5% of iron, 0.03-0.3% of silicon, 0.003-0.03% of copper and 0.01-0. l of titanium. The electrolyte used for electrolytic roughening may be an aqueous solution of an acid, base or salt or an aqueous solution containing an organic solvent. Among them, hydrochloric acid, nitric acid or an aqueous solution of a salt thereof is preferably used as the electrolyte. Firstly, the aluminum plate is put into 1% -30% aqueous solution of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate and the like, and chemical corrosion is carried out for 5-250 seconds at the temperature of 20-80 ℃. Then neutralizing in 10% -30% nitric acid or sulfuric acid at 20-70 deg.C to remove gray matter. The cleaned aluminum plate is electrolyzed in electrolyte of nitric acid or hydrochloric acid at the temperature of 10-60 deg.c for 10-300 sec with rectangular wave, table wave, sine wave, etc. of positive and negative alternate change and current density of 5-100A/d square meter. Subsequently, the electrolytic aluminum plate is subjected to anodic oxidation treatment. Anodic oxidation is typically carried out by the sulfuric acid process. The concentration of the used sulfuric acid is 5-30%, the current density is 1-15A/d square meter, the oxidation temperature is 20-60 ℃, and the oxidation time is 5-250 seconds, so that an oxidation film of 1-10 g/square meter is formed. The oxide film formed in this way usually has high oxide film micropores, has strong adsorption capacity, and is easy to adhere dirt. Therefore, a sealing treatment is usually required. The sealing treatment may be carried out by various methods, preferably by sealing 50 to 80% by volume of the micropores of the oxide film. Finally, polyvinyl phosphonic acid is coated on the aluminum plate treated in the way, and the thickness of the polyvinyl phosphonic acid is 3mg/m²。

The negative photosensitive composition comprises discrete nano-micron particles, a diuridone prepolymer, a polyfunctional monomer, a thermal polymerization initiator, an infrared absorbent and an organic metal accelerator. The plate material has a brand new multiple thermal-sensitive imaging mechanism, can realize nano-micron particle hot melting thermoplasticity, free baseline thermal polymerization and polyurethane reticular thermal crosslinking, strong polar urethane bonds have high wear resistance, the urethane bond reticular crosslinking structure enables the plate material to obtain ultrahigh printing resistance, and the plate material can be directly printed on a machine, so that the green environmental protection is realized.

The discrete nano-micro particles in the negative-working photosensitive composition are first described.

The heat-sensitive plate is designed by considering the heat-sensitive coating of the plate, wherein the heat-sensitive coating needs an important binder, namely functional film-forming resin, and the resin can form a film after ensuring that the coating liquid is dried so as to ensure that the heat-sensitive coating is attached to a support. The binder may be in the form of a solution or an emulsion. The discrete nano-micro particles in the negative photosensitive composition of the invention are such binders.

The particle size of the discrete nano-micron particles in the negative photosensitive composition is 50-300nm, the weight average molecular weight is 40000-10000, and the negative photosensitive composition has the following structure:

Most of the chemical treatment-free thermosensitive CTP plate discrete nano-micron particle adhesives are designed with thermoplastic styrene structural units, and the thermoplastic nano-micron particles also contain thermoplastic styrene structural units. As is well known, the styrene structural unit has good thermoplasticity and higher glass transition temperature, and the styrene copolymer used as the adhesive of the chemical treatment-free thermosensitive CTP plate has the advantages that the heated part is easier to melt, the arrangement among molecules is tighter, the thermal image part is firmer, and the printing resistance of the plate can be increased. The content of styrene in the copolymer directly affects the glass transition temperature and the thermoplasticity of the polymer. The multipolymer of the invention is synthesized, and the content of the styrene copolymerization unit in the multipolymer is 40 to 70 percent by weight.

It is necessary to design a CTP plate binder and select an excellent hydrophobic segment. Cyano groups are relatively excellent hydrophobic groups. The thermoplastic nano-micron particles of the invention are introduced with hydrophobic side chain cyano groups, and the copolymer is used as an adhesive thermoplastic fusion imaging part after being introduced with the hydrophobic side chain cyano groups, and has good flexibility, drug resistance and hydrophobicity. The method for introducing hydrophobic side chain group nitrile into the multipolymer is to design a vinyl component structural unit of side chain group-containing nitrile in a copolymerization component, preferably acrylonitrile or methacrylonitrile or a mixture of the acrylonitrile or the methacrylonitrile. The multipolymer of the invention is synthesized, and the content of the (methyl) acrylonitrile copolymerization unit in the multipolymer is 10 to 30 percent by weight.

The plate material designed by the invention has the capability of net-shaped thermal crosslinking, the heat of infrared laser leads the diurea ketone in the diurea ketone prepolymer to generate thermal splitting through the laser energy transferred by an infrared absorbent, active isocyanate (-NCO) is generated, the active isocyanate (-NCO) and branched chain hydroxyl (-OH) in nano-micron particles generate polyurethane reaction under the catalysis of an organic metal accelerator, strong polar urethane bond (-NHCOO) is formed, and the net-shaped thermal crosslinking of polyurethane is realized while the free base linear polymerization is realized. The invention introduces branched hydroxyl into a discrete nano-micron particle polymer resin structure chain, selects hydroxyl-containing acrylic monomers as copolymerization units, the hydroxyl-containing acrylic monomers comprise 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate (HPA), 2-hydroxyethyl methacrylate (HEMA), 2-hydroxypropyl methacrylate (HPMA) and the like, and the weight percentage content of the hydroxyl-containing acrylic monomer copolymerization units in the multipolymer is 10-30%.

As the chemical treatment-free CTP emulsion adhesive, the thermoplastic nano-micron particles contain self-emulsifying structural units better, the polymer can realize emulsification by polyether emulsifying groups under the condition of no external emulsifier, and the synthesized emulsion particles are more uniform and smooth than external emulsion particles and have better stability. The thermoplastic nano-micron particles of the invention are designed with polyether self-emulsifying structural units in the copolymerization component, including esterified branched polyether and urethanized branched polyether, and the specific examples are as follows (without being limited thereto):

A1:

A2:

the weight percentage content of the polyether self-emulsifying structure copolymerization unit in the multipolymer is 10-30%.

The synthesis of the thermoplastic nano-micron particles adopts an emulsion copolymerization method, and the copolymerization reaction can be random copolymerization or block copolymerization, preferably random copolymerization. Initiators for polymerization include peroxides such as di-t-butyl peroxide, benzoyl peroxide, persulfates such as potassium persulfate, amine persulfate, azo compounds such as azobisisobutyronitrile, and the like. The copolymerization mode adopts emulsion polymerization.

As the reaction solvent, there can be mentioned water, methanol, ethanol, N-propanol, isopropanol, butanol, acetone, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, tetrahydrofuran, 1, 4-dioxane, N-dimethylformamide, dimethylacetamide acetone, methyl ethyl ketone, cyclohexane, ethylene dichloride, toluene, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol dimethyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, acetylacetone, diacetone alcohol, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol isopropyl ether, ethylene glycol butyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, dimethyl sulfoxide, methyl lactate, ethyl lactate and the like, or a mixture thereof. It is advantageous to use mixtures of alcohols and water, preferably n-propanol-water or isopropanol-water mixtures. The emulsion copolymerization reaction temperature is preferably 40 to 100 ℃, and most preferably 60 to 90 ℃.

The thermoplastic nano-micron particles are synthesized, a feeding mode adopts a mode of dropwise adding partial raw materials, the particle size of the thermoplastic nano-micron particles can be controlled by changing the concentration of a reaction system and the dropwise adding time, the diameter of the thermoplastic nano-micron particles is reduced along with the reduction of the concentration of the reaction system and the increase of the dropwise adding time, and the particle size of the thermoplastic nano-micron particles can be controlled in a nano-scale by adjusting the concentration of the reaction system and the dropwise adding time. The diameter of the discrete nano-micron particles in the negative photosensitive composition is 50-300 nm.

The weight average molecular weight of the thermoplastic nano-micron particles is 40000-10000, and the glass transition temperature is 110-130 ℃.

The nano-micron particles designed by the invention account for 30-70%, preferably 40-60% of the total solid content of the negative photosensitive composition.

Next, the diurea ketone prepolymer in the negative photosensitive composition will be described.

The plate material designed by the invention has the capability of net-shaped thermal crosslinking, the heat of infrared laser leads the diurea ketone in the diurea ketone prepolymer to generate thermal splitting through the laser energy transferred by an infrared absorbent (dye) to generate active isocyanate (-NCO), the active isocyanate (-NCO) and branched chain hydroxyl (-OH) in nano-micron particles generate polyurethane reaction under the catalysis of an organic metal accelerator to form strong polar urethane bond (-NHCOO), and the net-shaped thermal crosslinking of polyurethane is realized while the free-radical linear polymerization is realized.

The diurea ketone prepolymer in the negative photosensitive composition has the following structural general formula:

wherein R is:

the laser pyrolysis mechanism is illustrated as follows:

diuranones are dimers of two isocyanate groups provided by two different structures of isocyanate (-R1-NCO, -R2-NCO) or by one of the same structures of isocyanate (-RNCO). The two isocyanate groups for synthesizing the diurea ketone are provided by isocyanate- (RNCO) with the same structure. The diuranone synthesized by isocyanate groups provided by isocyanate with the same structure has symmetrical structure and good stability at normal temperature, and active isocyanate (-NCO) groups are quickly decomposed at high temperature under the action of laser.

The diuridone prepolymer designed by the invention contains unsaturated double bonds, and the unsaturated double bonds are connected with isocyanate groups through hydroxyl groups, so the selected isocyanate is diisocyanate. Diisocyanates include aromatic diisocyanate Toluene Diisocyanate (TDI) and diphenylmethane diisocyanate (MDI), p-phenylene diisocyanate (PPDI), Naphthalene Diisocyanate (NDI), dimethylbiphenyl diisocyanate (TODI); aliphatic and cycloaliphatic isomers are 1, 6-Hexamethylene Diisocyanate (HDI), 1-isocyanate-3-isocyanatomethylene-3, 5, 5-trimethyl-cyclohexyl (isophorone diisocyanate, IPDI), 4' -diisocyanate dicyclohexylmethane (H12MDI), Xylylene Diisocyanate (XDI), cyclohexane diisocyanate (CHDI), tetramethylxylylene diisocyanate (TMXDI), 1, 3-bis (isocyanatomethyl) cyclohexane (H6XDI), and the like. The diisocyanate selected for synthesizing the biurea ketone prepolymer in the invention is aromatic diisocyanate or diisocyanate containing cyclohexyl. Considering the good stability at normal temperature and the laser pyrolysis property of the diuridone prepolymer, the diisocyanate selected by the invention is diphenylmethane diisocyanate (MDI), 4' -diisocyanate dicyclohexylmethane (H12MDI), Xylylene Diisocyanate (XDI), Toluene Diisocyanate (TDI) and Naphthalene Diisocyanate (NDI).

The unsaturated double bond contained in the diurea ketone prepolymer designed by the invention is connected with isocyanate group through hydroxyl, and the unsaturated double bond monomer containing hydroxyl comprises 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate (HPA), 2-hydroxyethyl methacrylate (HEMA), 2-hydroxypropyl methacrylate (HPMA), pentaerythritol triacrylate (PETA) and the like. Considering the activity of unsaturated double bond and the good stability of diurea ketone prepolymer at normal temperature and laser pyrolysis, the unsaturated double bond monomer containing hydroxyl is methacrylic acid-2-hydroxyethyl methacrylate (HEMA) and pentaerythritol triacrylate (PETA).

The diuridone prepolymer designed by the invention accounts for 10-50%, preferably 20-40% of the total solid of the negative photosensitive composition.

The photopolymerizable polyfunctional monomer comprises diacrylate, 1, 6-hexanediol diacrylate, pentaerythritol triacrylate and tetraacrylate, 1,3, 5-tris (2-acryloyloxyethyl) isocyanurate, hydroxypropyl glyceryl triacrylate, hydroxyethyl trimethylolpropane triacrylate, polyethylene glycol dimethacrylate and the like. The polyfunctional monomer accounts for 10-30% of the dry weight of the coating film in the photosensitive coating, preferably 10-20%.

The components of the heat-sensitive negative-working composition of the invention are described in detail below: a thermal polymerization initiator.

The thermosensitive plate is a polymerizable plate, the plate has the capability of free radical thermal polymerization, the heat of infrared laser transmits laser energy to a thermal polymerization initiator through an infrared absorbent, the thermal polymerization initiator releases active primary free radicals, and the primary free radicals initiate unsaturated double bonds in a polyfunctional group monomer and a diurea ketone prepolymer to realize free radical linear polymerization.

The thermal polymerization initiator in the invention is heated and decomposed to generate primary free radicals, and the unsaturated double bonds are initiated to generate free radical polymerization. There are many kinds of thermal polymerization initiators capable of initiating radical polymerization, including peroxides such as hydrogen peroxide, ammonium persulfate, potassium persulfate, benzoyl peroxide t-butyl peroxide, methyl ethyl ketone peroxide, etc.; azo compounds such as azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate, azo compounds having a carboxyl group or a sulfonic group, and azobisisobutylamidine hydrochloride; onium salts such as iodonium salt, sulfonium salt and the like; and triazine compounds containing halogen substitution, and the like. Considering their stability at room temperature and sensitivity to laser thermal decomposition, halogen-substituted triazine compounds are preferable. The thermal polymerization initiator is 1 to 20%, preferably 5 to 15% of the total solid content of the composition of the negative photosensitive composition.

The components of the heat-sensitive negative-working composition of the invention are described in detail below: an infrared absorber.

The components in the thermosensitive plate composition of the invention are as follows: the infrared absorbent mainly plays a role in energy transfer, the heat of infrared laser transfers laser energy to the thermal polymerization initiator through the infrared absorbent, the thermal polymerization initiator releases active primary free radicals, and the primary free radicals initiate unsaturated double bonds in the polyfunctional monomer and the diurea ketone prepolymer to realize free-radical linear polymerization; meanwhile, the heat of the infrared laser is utilized to carry out thermal splitting on the diurea ketone in the diurea ketone prepolymer through the laser energy transferred by the infrared absorbent, so as to generate active isocyanate groups (-NCO), and the active isocyanate groups (-NCO) and branched chain hydroxyl groups (-OH) of the discrete nano-micron particles are subjected to polyurethane reaction under the catalytic action of the organic metal accelerator, so as to form urethane bonds (-NHCOO), realize the linear polymerization of free radicals and realize the reticular thermal crosslinking of polyurethane.

The infrared absorbing compound contained in the negative photosensitive composition has a maximum absorption wavelength range of 750-1100nm, 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. The negative photosensitive composition of the invention comprises the following components: the infrared absorbent is cyanine dye with the maximum absorption range of preferably 750-850nm, and the infrared absorbent accounts for 1-20% of the dry weight of the coating in the photosensitive coating, preferably 5-15%.

The components contained in the negative photosensitive composition of the present invention are described in detail below: an organometallic promoter.

The thermal sensitive plate has the characteristic of polyurethane thermal crosslinking, the heat of infrared laser leads diurea ketone in diurea ketone prepolymer to generate thermal splitting through the laser energy transferred by an infrared absorbent, active isocyanate (-NCO) is generated, the active isocyanate (-NCO) and branched chain hydroxyl (-OH) of discrete nano-micron particles generate polyurethane reaction under the catalysis of an organic metal accelerant, an ammonia ester bond (-NHCOO) is formed, and the reticular thermal crosslinking of polyurethane is realized while the linear polymerization of free radicals is realized.

Polyurethane reactions generally require catalysts, and there are many catalysts that promote polyurethane reactions, and polyurethane catalysts can be divided into two broad classes, amine compounds and organometallic compounds. Amine compounds such as Triethylenediamine (TEDA), Dimethylcyclohexylamine (DMCHA), Dimethylethanolamine (DMEA), Tetramethylbutanediamine (TMBDA), dimethylaminebisethylether (a-99) Benzyldimethylamine (BDMA), and the like; organometallic compounds such as mercury, lead, tin, bismuth, zinc, iron, and the like. The components of the thermosensitive plate composition of the invention are as follows: the organic metal promoter is stable and efficient organic metal tin compound, such as diisobutyl tin laurate, stannous octoate, etc. The organometallic tin compound is preferably present in the photosensitive coating in an amount of 0.5 to 5%, preferably 1 to 3%, based on the dry weight of the coating film.

The negative photosensitive composition of the present invention may further comprise other necessary auxiliaries such as a solvent, a thermal polymerization inhibitor at room temperature, a coating colorant, a surfactant and the like.

The solvent is mainly used for preparing the thermosensitive coating photosensitive solution, and the preparation of the thermosensitive coating photosensitive solution solvent comprises the following steps: acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol dimethyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol isopropyl ether, ethylene glycol butyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, n.n-dimethylformamide, dimethyl sulfoxide, methyl lactate, and ethyl lactate, and the like. The solvents can be used in pure form or as mixtures.

The normal temperature thermal polymerization inhibitor is used for preventing the sheet material from polymerizing at normal temperature and improving the normal temperature stability of the plate material. The thermal polymerization inhibitor includes: hydroquinone, nitroxide radical piperidinol, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4 '-thiobis- (3-methyl-6-t-butylphenol), 2' -methylenebis (4-methyl-16-t-butylphenol), and the primary cerium salt of N-nitrosophenylhydroxylamine, and the like.

The heat sensitive coating contains a coating colorant. In order to increase the image density of the heat-sensitive plate after the plate is made and facilitate the visual inspection of the heat-sensitive plate after the plate is made or the plate performance measurement of image analysis and measurement equipment, the heat-sensitive layer of the heat-sensitive plate is added with a layer coloring agent. It includes: methyl violet, ethyl violet, crystal violet, victoria blue, oil green, oil blue, oil yellow, rhodamine B, methyl violet, malachite green, methylene blue, triazines, and the like.

The heat sensitive coating contains a surfactant, and can be selected from nonionic surfactants, amphoteric surfactants, silicon-containing surfactants, fluorine-containing surfactants and the like. Such as betaines, glyceryl stearates, sorbitan esters, silicones, polyfluoroalkyl ethers.

The protective layer with the nano-micro structure over the coating layer is described below. The protective layer is to prevent oxygen present in the air or other contaminants in the environment from affecting the performance of the heat sensitive coating. As the material for the protective layer, water-soluble polymers such as poly (vinyl alcohol), polyvinylpyrrolidone, acidic cellulose derivatives, gelatin, gum arabic and the like can be selected, but these materials such as polyvinyl alcohol are dissolved and accumulated in dampening water for a long time, pollute dampening solution, and in addition, the protective layer material has poor normal temperature permeability after film forming, is difficult to remove under the action of dampening water and ink, and causes the number of paper passing through the plate to be increased sharply, and wastes paper.

The present invention solves the above problems by using a hydrophilic, water-insoluble, protective layer having a nano-micro structure. The protective layer of the present invention uses particles having a particle size of 50 to 150nm among the above-described discrete nano-micro particles as the protective layer. Unexposed nano-micron particle structure has excellent wetting property of fountain solution and removability of printing ink, but is insoluble and does not pollute the fountain solution, and can be easily removed through a printing machine fountain solution cleaning and filtering system, and nano-micron particles of the exposed part of a protective layer and nano-micron particles of a photosensitive layer are demulsified and melted by laser to form a fused integral structure, namely, the protective layer of the image-text part occupying most area of a plate surface does not enter a fountain solution system, so that the capability of the protective layer to pollute the fountain solution is greatly reduced. The particle size of the nano-micron particles can be matched only when the particle size is moderate, the air tightness of the protective film is poor due to the overlarge particle size, the wettability of the protective film is poor due to the undersize particle size, the contradiction between the air tightness and the wettability must be balanced, and the particle size of the nano-micron structure protective layer particles is 50-150nm, so that good oxygen resistance and development removability can be obtained.

The coating amount of the protective layer is usually 5 to 20mg/dm by dry mass²Preferably 10-15mg/dm²。

The heat-sensitive compositions of the present invention are typically coated (e.g., knife coated, bar coated, roll coated, press coated, etc.) onto an aluminum substrate using techniques known in the art.

Drawings

FIG. 1 is a schematic diagram of the plate structure of an on-press development process-free thermosensitive plate with a nano-micro structure protective layer.

Detailed Description

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

Raw materials are available from the following companies: styrene St: shandong Han Zun energy science and technology, Inc.; methacrylonitrile MAN, acrylonitrile AN: tianjin chemical reagent II; hydroxyethyl methacrylate HEMA, hydroxyethyl acrylate HEA, hydroxypropyl methacrylate HPMA, hydroxypropyl acrylate HPA: mitsubishi corporation of japan; exemplary compounds a1, a 2: SIGMA corporation, UK; isopropyl alcohol: yangzhou Chengyu chemical industry; azobisisobutyronitrile: fosen chemistry; benzoyl peroxide BPO, a Laiwukang new reagent.

A first part: synthesis examples of discrete Nano-micro emulsion particles (code P) P1-P10

Synthesis example 1 (emulsion particles P1)

300g of isopropanol, 100g of deionized water, 10g (10 wt%) of the exemplified compound A1(n is 60) were placed in a 1000ml four-necked flask with temperature-controlled heating, mechanical stirring, reflux condensation and nitrogen protection, and the mixture was stirred while heating, 70g (70 wt%) of St (styrene), 10g (10 wt%) of AN (acrylonitrile), 10g (10 wt%) of HEMA hydroxyethyl methacrylate and 0.7g of AIBN (azobisisobutyronitrile) were added dropwise at 80 ℃ for 1 hour, reacted for 7.5 hours, then 0.3g of AIBN (azobisisobutyronitrile) was added, and the reaction was continued for 12 hours.

The solids content was 25%, the GPC molecular weight was 93600, and the particle diameter was 200 nm.

Synthesis example 2 (emulsion particle P2)

357g of isopropanol, 119g of deionized water, 10g (10 wt.%) of the exemplified compound A2(n is 50) were added to a 1000ml four-necked flask with temperature-controlled heating, mechanical stirring, reflux condensation and nitrogen protection, and the mixture was stirred while heating, 60g (60 wt.%) of St (styrene), 20g (20 wt.%) of AN (acrylonitrile), 10g (10 wt.%) of HEMA hydroxyethyl methacrylate and 0.7g of AIBN (azobisisobutyronitrile) were added dropwise at 60 ℃ for 1.5 hours, and after 7.5 hours of further reaction, 0.3g of AIBN (azobisisobutyronitrile) was added, and the reaction was completed after 12 hours of further reaction.

The solids content (solute/solvent) was 21%, the GPC molecular weight was 76800, and the particle diameter was 150 nm.

Synthesis example 3 (emulsion particle P3)

417g of isopropanol, 139g of deionized water, 10g (10% by weight) of the exemplified compound A1(n is 40) were placed in a 1000ml four-neck flask with temperature-controlled heating, mechanical stirring, reflux condensation and nitrogen protection, and the mixture was stirred while heating, 50g (50% by weight) of St (styrene), 30g (30% by weight) of AN (acrylonitrile), 10g (10% by weight) of hydroxyethyl HEA acrylate and 0.7g of AIBN (azobisisobutyronitrile) were added dropwise at 60 ℃ for 2.0 hours, and after 7.5 hours of further reaction, 0.3g of AIBN (azobisisobutyronitrile) was added and the reaction was continued for 12 hours.

The solid content was 18%, the GPC molecular weight was 63700, and the particle diameter was 100 nm.

Synthesis example 4 (emulsion particle P4)

500g of isopropanol, 167g of deionized water, 10g (10 wt%) of the exemplified compound A2(n is 20) were placed in a 1000ml four-necked flask with temperature-controlled heating, mechanical stirring, reflux condensation and nitrogen protection, and the mixture was stirred while heating, 40g (40 wt%) of St (styrene), 10g (10 wt%) of AN (acrylonitrile), 20g (20 wt%) of hydroxyethyl HEA acrylate and 0.7g of AIBN (azobisisobutyronitrile) were added dropwise at 60 ℃ for 2.5 hours, reacted for 7.5 hours, then 0.3g of AIBN (azobisisobutyronitrile) was added, and the reaction was continued for 12 hours.

The solids content was 15%, the GPC molecular weight was 40500, and the particle diameter was 50 nm.

Synthesis example 5 (emulsion particles P5)

250g of isopropanol, 83.3g of deionized water, 10g (10 wt%) of the exemplified compound A1(n is about 50) were placed in a 1000ml four-necked flask with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection, heated and stirred uniformly, 60g (60 wt%) of St (styrene), 10g (10 wt%) of MAN (methacrylonitrile), 20g (20 wt%) of HEPA hydroxypropyl methacrylate and 0.7g of benzoyl peroxide BPO were added dropwise at 90 ℃ for 0.5 hour, and after 7.5 hours of further reaction, 0.3g of benzoyl peroxide BPO was added, and after 12 hours of further reaction, the reaction was completed.

The solids content was 30%, the GPC molecular weight was 102400, and the particle diameter was 300 nm.

Synthesis example 6 (emulsion particles P6)

268g of isopropanol, 89.3g of deionized water, 10g (10 wt%) of the exemplified compound A2(n is 40) were added to a 1000ml four-necked flask with temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection, the mixture was heated and stirred uniformly, 50g (50 wt%) of St (styrene), 10g (10 wt%) of MAN (methacrylonitrile), 30g (30 wt%) of HPMA hydroxypropyl methacrylate and 0.7g of benzoyl peroxide BPO were added dropwise at 85 ℃ for 45 minutes, the mixture was reacted for 7.5 hours, then 0.3g of benzoyl peroxide BPO was added, and the reaction was continued for 12 hours.

The solids content was 28%, the GPC molecular weight was 97500, and the particle diameter was 250 nm.

Synthesis example 7 (emulsion particles P7)

A1000 ml four-necked flask with temperature-controlled heating, mechanical stirring, reflux condensation and nitrogen protection was charged with 312.5g of isopropanol, 104.1g of deionized water, 30g (30 wt%) of the exemplified compound A1(n about 20), heated and stirred uniformly, 40g (40 wt%) of St (styrene), 20g (20 wt%) of MAN (methacrylonitrile), 10g (10 wt%) of HPA hydroxypropyl acrylate and 0.7g of AIBN (azobisisobutyronitrile) were added dropwise at 80 ℃ for 1 hour and 20 minutes, reacted for 7.5 hours, and then 0.3g of AIBN (azobisisobutyronitrile) was added, and the reaction was continued for 12 hours and then ended.

The solid content was 24%, the GPC molecular weight was 91300, and the particle diameter was 180 nm.

Synthesis example 8 (emulsion particles P8)

441g of isopropanol, 147g of deionized water, 20g (20 wt%) of the exemplified compound A2(n is 60) were added to a 1000ml four-necked flask equipped with a temperature-controlled heating device, a mechanical stirring device, a condensing reflux device and a nitrogen blanket, and the mixture was stirred while heating, 60g (60 wt%) of St (styrene), 10g (10 wt%) of AN (acrylonitrile), 10g (10 wt%) of hydroxypropyl HPA acrylate and 0.7g of AIBN (azobisisobutyronitrile) were added dropwise at 65 ℃ for 2.5 hours, reacted for 7.5 hours, added with 0.3g of AIBN (azobisisobutyronitrile), and the reaction was terminated after further 12 hours.

The solids content was 17%, the GPC molecular weight was 56400, and the particle diameter was 70 nm.

Synthesis example 9 (emulsion particle P9)

375g of isopropanol, 125g of deionized water, 30g (30 wt.%) of the exemplified compound A1(n is 30) were added to a 1000ml four-neck flask with temperature-controlled heating, mechanical stirring, reflux condensation and nitrogen protection, the mixture was stirred while heating, 50g (50 wt.%) of St (styrene), 10g (10 wt.%) of AN (acrylonitrile), 10g (10 wt.%) of HEMA hydroxyethyl methacrylate and 0.7g of AIBN (azobisisobutyronitrile) were added dropwise at 70 ℃ for 2 hours and 15 minutes, the mixture was reacted for 7.5 hours, 0.3g of AIBN (azobisisobutyronitrile) was added, and the reaction was completed after 12 hours.

The solids content was 20%, the GPC molecular weight was 68700, and the particle diameter was 90 nm.

Synthesis example 10 (emulsion particles P10)

In a 1000ml four-necked flask with temperature-controlled heating, mechanical stirring, reflux condensation and nitrogen protection, 326g of isopropanol, 108.7g of deionized water, 10g (10 wt.%) of the exemplified compound A2(n is about 60) were placed, heated and stirred uniformly, 40g (40 wt.%) St (styrene), 30g (30 wt.%) of AN (acrylonitrile), 10g (10 wt.%) of hydroxyethyl HEA acrylate and 0.7g of AIBN (azobisisobutyronitrile) were added dropwise at 80 ℃ for 1 hour, reacted for 7.5 hours, then 0.3g of AIBN (azobisisobutyronitrile) was added, and the reaction was continued for 12 hours and ended.

The solids content was 23%, the GPC molecular weight was 85400, and the particle diameter was 130 nm.

b: diurea ketone prepolymer: synthesis examples b1-b5

Raw materials are available from the following companies: pentaerythritol triacrylate PETA: sartomer, SR444, sartomer, usa; 2-hydroxyethyl methacrylate: mitsubishi corporation of japan; xylene methane diisocyanate MDI, Japan Tri-well chemistry; toluene diisocyanate TDI: japan polyurethane industries Ltd; xylylene diisocyanate XDI manufactured by Takenato, Wuta chemical industries, Japan; naphthalene-1, 5-diisocyanate NDI, Sandhoo pressure chemical Co., Ltd, Japan; dicyclohexylmethane diisocyanate HMDI Bayer, Desodurw; methyl ethyl ketone MEK: japan is perfecting petrochemicals.

Example of synthesis of compound b 1:

298.0g of pentaerythritol triacrylate PETA and 1.0g of dibutyltin dilaurate are added into a 2000ml four-neck flask with a temperature-controlled heating device, mechanical stirring device, condensation reflux device and a nitrogen protection device, nitrogen protection is carried out, 500.5g of molten xylene methane diisocyanate MDI is added dropwise when the temperature is 60 ℃, the dropping time is 30 minutes, after 2 hours of reaction, 130.1g of 2-hydroxyethyl methacrylate is added dropwise, the dropping time is 30 minutes, the reaction is carried out for 2 hours again, 232.1g of methyl ethyl ketone is added, and the reaction is carried out in an ice-water bath for 48 hours until the peak of active isocyanate 2275 disappears through infrared spectrum detection, so that the MEK solution of the compound 1 with the solid content of 80% is obtained.

Example of synthesis of compound b 2:

298.0g of pentaerythritol triacrylate PETA and 1.0g of dibutyltin dilaurate are added into a 1000ml four-neck flask with a temperature-controlled heating device, a mechanical stirring device, a condensation reflux device and a nitrogen protection device, nitrogen protection is carried out, 348.3g of toluene diisocyanate TDI is added dropwise when the temperature is increased to 60 ℃, the dropping time is 30 minutes, after 2 hours of reaction, 130.1g of 2-hydroxyethyl methacrylate is added dropwise, the dropping time is 30 minutes, the reaction is carried out for 2 hours again, 194.1g of methyl ethyl ketone is added, and the reaction is carried out for 48 hours in an ice water bath until the peak of active isocyanate group 2275 disappears through detection, so that the MEK solution of the compound b2 with the solid content of 80% is obtained.

Example of synthesis of compound b 3:

298.0g of pentaerythritol triacrylate PETA and 1.0g of dibutyltin dilaurate are added into a 1000ml four-neck flask with a temperature-controlled heating device, mechanical stirring is carried out, condensation reflux is carried out, a nitrogen protection device is arranged, 376.4g of xylylene diisocyanate XDI is added dropwise when the temperature is increased to 60 ℃ and the nitrogen protection device is carried out, the dropping time is 30 minutes, 130.1g of 2-hydroxyethyl methacrylate is added dropwise after 2-hour reaction, the dropping time is 30 minutes and then the reaction is carried out for 2 hours, 201.1g of methyl ethyl ketone is added, the reaction is carried out in an ice-water bath for 48 hours until the peak of active isocyanate 2275 disappears through infrared spectrum detection, and the MEK solution of the compound 3 with the solid content of 80% is obtained.

Compounds b4 as examples:

298.0g of pentaerythritol triacrylate PETA and 1.0g of dibutyltin dilaurate were added to a 2000ml four-neck flask with a temperature-controlled heating, mechanical stirring, condensation reflux and nitrogen protection device, the flask was heated to 60 ℃ under nitrogen protection, 420.0g of fused naphthalene-1, 5-diisocyanate NDI was added dropwise over a period of 30 minutes, 130.1g of 2-hydroxyethyl methacrylate was added dropwise after 2 hours of reaction, the dropwise addition was carried out over a period of 30 minutes, the reaction was carried out for 2 hours again, 212.0g of methyl ethyl ketone was added, and the reaction was carried out in an ice water bath for 48 hours until the peak at 2275 for active isocyanate groups disappeared by infrared spectroscopy, whereby an MEK solution of compound b4 with a solid content of 80% was obtained.

Example of synthesis of compound b 5:

298.0g of pentaerythritol triacrylate PETA and 1.0g of dibutyltin dilaurate are added into a 2000ml four-neck flask with a temperature-controlled heating device, mechanical stirring device, condensation reflux device and a nitrogen protection device, nitrogen protection is carried out, 524.0g of dicyclohexylmethane diisocyanate HMDI is added after heating to 60 ℃, the adding time is 30 minutes, 130.1g of 2-hydroxyethyl methacrylate is added after 2 hours of reaction, the adding time is 30 minutes, the reaction is carried out for 2 hours again, 238.0g of methyl ethyl ketone is added, and the reaction is carried out in an ice-water bath for 48 hours until the peak of 2275 active isocyanate groups disappears through infrared spectrum detection, so that the MEK solution of the compound b5 with the solid content of 80% is obtained.

The photosensitive composition of the present invention is dissolved in an appropriate solvent to prepare a coating solution. The following photosensitive liquid is extruded and coated on the aluminum plate base, and then the aluminum plate base is dried for 60 seconds at the temperature of 110 ℃ to obtain the dry weight of the coating of 1.8g per square meter.

The following are examples of the practice of the process-free thermal plate of the present invention, but are not limited to the following examples:

example 1

Preparing a substrate: a1050-rolled aluminum plate having a purity of 99.5% and a thickness of 0.3mm was immersed in a 5% aqueous solution of sodium hydroxide at 70 ℃ for 20 seconds, washed with running water, and immediately neutralized with A1% aqueous solution of nitric acid. Then, the mixture was subjected to a sine wave alternating current at 40 ℃ in a 1% hydrochloric acid aqueous solution at a frequency of 50A/dm²Current density electrolytic roughening for 16 seconds. Then, the mixture was neutralized with a 5% aqueous solution of sodium hydroxide at 40 ℃ for 10 seconds. And (5) washing with water. Finally, at 30 ℃, using 20% sulfuric acid water solution at 15A/dm²The current density of (2) was adjusted to anodic oxidation for 20 seconds, washed with water, and subjected to pore sealing treatment with a 5% aqueous solution of sodium silicate at 80 ℃ for 18 seconds. And (5) washing with water. And (5) drying. The substrate thus obtained had an average thickness of 0.5 μm in the center line and a weight of the oxide film of 3.0g/dm²。

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

coating a protective layer: the emulsion particles P3 were extrusion-coated on the photosensitive layer obtained above, followed by drying at 110 ℃ for 60 seconds to give 10mg/dm²Dry weight of coating (parts by weight of each component).

The infrared absorbing dye ADS830 has the following structure:

the plate thus obtained was subjected to Kodak-win thermosensitive CTP plate-making machine at 120mJ/cm²Is exposed to light. The properties are shown in Table 2 below.

Example 2

The same method as above was used to prepare the substrate and the photosensitive layer. The photosensitive solution comprises the following components:

Example 3

coating a protective layer: in the above-mentioned orderThe resultant photosensitive layer was extrusion-coated with emulsion particles P4, and then dried at 110 ℃ for 60 seconds to give 10mg/dm²Dry weight of coating (parts by weight of each component).

Example 4

coating a protective layer: the emulsion particles P4 were extrusion-coated on the photosensitive layer obtained above, followed by drying at 110 ℃ for 60 seconds to give 10mg/dm²Dry weight of coating (parts by weight of each component).

Example 5

coating a protective layer: the emulsion particles P8 were extrusion-coated on the photosensitive layer obtained above, followed by drying at 110 ℃ for 60 seconds to give 10mg/dm²Dry weight of coating (parts by weight of each component).

Example 6

the emulsion particles P8 were extrusion-coated on the photosensitive layer obtained above, followed by drying at 110 ℃ for 60 seconds to give 10mg/dm²Dry weight of coating (parts by weight of each component).

Example 7

coating a protective layer: the emulsion particles P9 were extrusion-coated on the photosensitive layer obtained above, followed by drying at 110 ℃ for 60 seconds to give 10mg/dm²Dry weight of coating (parts by weight of each component).

Example 8

The plate thus obtained has a heat-well of Kodak120mJ/cm on quick CTP platemaking machine²Is exposed to light. The properties are shown in Table 2 below.

Example 9

coating a protective layer: the emulsion particles P10 were extrusion-coated on the photosensitive layer obtained above, followed by drying at 110 ℃ for 60 seconds to give 10mg/dm²Dry weight of coating (parts by weight of each component).

Example 10

coating a protective layer: the emulsion particles P2 were extrusion-coated on the photosensitive layer obtained above, followed by drying at 110 ℃ for 60 seconds to give 10mg/dm²Dry weight of coating (parts by weight of each component).

Example 11

A substrate, a photosensitive layer and a protective layer were prepared in the same manner as in example 1. Except that the average thickness of the center line of the plate base is 0.4um, the plate material obtained in this way is 120mJ/cm on a Kodak full-win thermosensitive CTP platemaking machine²Is exposed to light. The properties are shown in Table 2 below.

Example 12

A substrate, a photosensitive layer and a protective layer were prepared in the same manner as in example 1. Except that the average thickness of the center line of the plate base was set to 0.6. mu.m, the plate thus obtained was subjected to a Kodak-win thermosensitive CTP plate-making machine at 120mJ/cm²Is exposed to light. The properties are shown in Table 2 below.

Example 13

A substrate, a photosensitive layer and a protective layer were prepared in the same manner as in example 1. Except that the dry coating weight of the photosensitive layer was 8mg/dm²The plate thus obtained was subjected to a Kodak-win thermosensitive CTP plate-making machine at 120mJ/cm²Is exposed to light. The properties are shown in Table 2 below.

Example 14

A substrate, a photosensitive layer and a protective layer were prepared in the same manner as in example 1. Except that the weight of the dried coating layer of the photosensitive layer was set to 15mg/dm²The plate thus obtained was subjected to a Kodak-win thermosensitive CTP plate-making machine at 120mJ/cm²Is exposed to light. The properties are listed in table 2 below.

Example 15

A substrate, a photosensitive layer and a protective layer were prepared in the same manner as in example 1. Except that the dry coating weight of the protective layer was set to 5mg/dm²The plate thus obtained was subjected to a Kodak-win thermosensitive CTP plate-making machine at 120mJ/cm²Is exposed to light. The properties are shown in Table 2 below.

Example 16

A substrate, a photosensitive layer and a protective layer were prepared in the same manner as in example 1. Except that the dry coating weight of the protective layer was 20mg/dm²The plate thus obtained was subjected to a Kodak-win thermosensitive CTP plate-making machine at 120mJ/cm²Is exposed to light. The properties are shown in Table 2 below.

Comparative example 1

Preparing a substrate: a1050-rolled aluminum plate having a purity of 99.5% and a thickness of 0.3mm was immersed in a 5% aqueous solution of sodium hydroxide at 70 ℃ for 20 seconds, washed with running water, and immediately neutralized with A1% aqueous solution of nitric acid. Then, the mixture was subjected to a sine wave alternating current at 40 ℃ in a 1% hydrochloric acid aqueous solution at a frequency of 50A/dm²Current density electrolytic roughening for 16 seconds. Then, the mixture was neutralized with a 5% aqueous solution of sodium hydroxide at 40 ℃ for 10 seconds. And (5) washing with water. Finally, at 30 ℃, using 20% sulfuric acid water solution at 15A/dm²The current density of (2) was adjusted to anodic oxidation for 20 seconds, washed with water, and subjected to pore sealing treatment with a 5% aqueous solution of sodium silicate at 80 ℃ for 18 seconds. And (5) washing with water. And (5) drying. The thus obtained plate had an average thickness of the center line of 0.5um and an oxide film weight of 3.0g/dm²。

Coating a photosensitive layer: the following photosensitive solution was extrusion-coated on the above-mentioned plate base subjected to the hydrophilization treatment, and then dried at 100 ℃ for 60 seconds. 10mg/dm was obtained²Dry weight of coating (2). The photosensitive solution used was the following composition (each component in parts by weight):

coating a protective layer: the photosensitive layer obtained above was extrusion-coated with the following protective layer solution, followed by drying at 110 ℃ for 60 seconds to obtain 10mg/dm²Dry weight of coating (parts by weight of each component).

Protective layer formula (each component is according to weight portion)

The infrared absorbing dye ADS830 has the following structure:

Comparative example 2

The substrate, photosensitive layer and protective layer were prepared in the same manner as above. The photosensitive solution comprises the following components:

Comparative example 3

Comparative example 4

Comparative example 5

Comparative example 6

Comparative example 7

Comparative example 8

Comparative example 9

Comparative example 10

Comparative example 11

The plate base, photosensitive layer and protective layer were prepared in the same manner as in comparative example 1. Except that the average thickness of the center line of the plate base is 0.4um, the plate material obtained in this way is 120mJ/cm on a Kodak full-win thermosensitive CTP platemaking machine²Is exposed to light. The properties are shown in Table 2 below.

Comparative example 12

The plate base, photosensitive layer and protective layer were prepared in the same manner as in comparative example 1. Except that the average thickness of the center line of the plate base is 0.6um, the plate material obtained in this way is 120mJ/cm on a Kodak full-win thermosensitive CTP platemaking machine²Is exposed to light. The properties are shown in Table 2 below.

Comparative example 13

The plate base, photosensitive layer and protective layer were prepared in the same manner as in comparative example 1. Except that the dry coating weight of the photosensitive layer was 8mg/dm²The plate thus obtained was subjected to a Kodak-win thermosensitive CTP plate-making machine at 120mJ/cm²Is exposed to light. The properties are shown in Table 2 below.

Comparative example 14

The plate base, photosensitive layer and protective layer were prepared in the same manner as in comparative example 1. Except that the weight of the dried coating layer of the photosensitive layer was set to 15mg/dm²

The plate thus obtained was subjected to Kodak-win thermosensitive CTP plate-making machine at 120mJ/cm²Is exposed to light. The properties are listed in table 2 below.

Comparative example 15

Preparation of a substrate and sensitization in the same manner as in comparative example 1A layer and a protective layer. Except that the dry coating weight of the protective layer was set to 5mg/dm²The plate thus obtained was subjected to a Kodak-win thermosensitive CTP plate-making machine at 120mJ/cm²Is exposed to light. The properties are shown in Table 2 below.

Comparative example 16

The plate base, photosensitive layer and protective layer were prepared in the same manner as in comparative example 1. Except that the dry coating weight of the protective layer was 20mg/dm²The plate thus obtained was subjected to a Kodak-win thermosensitive CTP plate-making machine at 120mJ/cm²Is exposed to light. The properties are shown in Table 2 below.

The detection and application results of the attached table show that the invention adopts the hydrophilic but water-insoluble protective layer with the nano-micron structure, solves the problem of poor normal temperature permeability after the protective layer is formed into a film, and improves the plate material and greatly reduces the number of paper passing the plate under the on-machine developing capability; meanwhile, the plate material has the advantages of high light sensitivity, good dot reducibility and high printing resistance by a multiple thermal sensitive imaging mechanism, can be directly printed on a machine without any washing processing step after being scanned and imaged by infrared laser, can obtain high printing resistance, and realizes green and environment-friendly printing.

Attached table 1: emulsion particle performance table

Attached table 2: plate material application performance table

Claims

1. An on-press development treatment-free thermosensitive plate with a nano-micron structure protective layer, which is characterized in that: it comprises an aluminum plate substrate support, a coating layer containing a negative photosensitive composition and a protective layer with a nano-micron structure, wherein the aluminum plate substrate support is distributed from bottom to top; the protective layer with the nano-micron structure comprises discrete nano-micron particles with the particle size of 50-150nm, and the structural formula is as follows:

R₁、R₂、R₄is H atom or methyl group, R₃Is CH₂CH₂OH or CH₂CH₂CH₂OH,R₅Is COO (CH)₂CH₂)_nH or COOCH₂CH₂NHCOO(CH₂CH₂)_nH, n is an integer of 20-60; a. b, c and d are the weight percentage of the corresponding copolymerization units, the proportion of a is 40-70%, the proportion of b is 10-30%, the proportion of c is 10-30%, and the proportion of d is 10-30%.

2. The on-press development process-free thermal plate with a nano-micro structured protective layer according to claim 1, wherein: the negative photosensitive composition mainly comprises, by weight, 40-60% of discrete nano-micron particles, 20-40% of diurea ketone prepolymer, 10-20% of polyfunctional monomer, 5-15% of thermal polymerization initiator, 5-15% of infrared absorbent and 1-3% of organic metal accelerator.

3. The on-press development process-free thermal plate with a nano-micro structured protective layer according to claim 2, wherein: the particle size of the discrete nano-micron particles in the negative photosensitive composition is 50-300nm, the weight average molecular weight is 40000-10000, and the negative photosensitive composition has the following structure:

4. The on-press development process-free thermal plate with a nano-micro structured protective layer according to claim 2, wherein: the diurea ketone prepolymer has the following structure:

wherein R is:

5. the on-press development process-free thermal plate with a nano-micro structured protective layer according to claim 2, wherein: the multifunctional monomer is a multifunctional acrylic monomer.

6. The on-press development process-free thermal plate with a nano-micro structured protective layer according to claim 2, wherein: the thermal polymerization initiator is a halogen substituted triazine compound, and the thermal decomposition temperature of the thermal polymerization initiator is 150-200 ℃.

7. The on-press development process-free thermal plate with a nano-micro structured protective layer according to claim 2, wherein: the infrared absorbent is a cyanine dye with an absorption peak at 750-850 nm.

8. The on-press development process-free thermal plate with a nano-micro structured protective layer according to claim 2, wherein: the organometallic promoter is an organometallic tin.

9. The on-press development process-free thermal plate with a nano-micro structured protective layer according to claim 1, wherein: the aluminum plate base supporting body is subjected to electrolytic coarsening, anodic oxidation and hole sealing treatment, and the average thickness of the central line is 0.4-0.6 mu m.

10. The on-press development process-free thermal plate with a nano-micro structured protective layer according to claim 1, wherein: the dry weight of the coating layer containing the negative photosensitive composition is 8-15mg/dm²。

11. The on-press development process-free thermal plate with a nano-micro structured protective layer according to claim 1, wherein: the dry weight of the protective layer with the nano-micron structure is 5-20mg/dm²。

12. The on-press development process-free thermal plate with a nano-micro structured protective layer according to claim 1, wherein: the on-press development treatment-free thermosensitive plate with the nano-micron structure protective layer can be directly installed on a printing machine for printing without any processing step after scanning exposure by using a thermosensitive CTP plate making machine.