Iodonium salt photoinitiators and their application in the preparation of treatment-free CTP thermal printing plates

Abstract

This invention discloses an iodonium salt photoinitiator and its application in the preparation of treatment-free CTP thermal printing plates. The general formula of the iodonium salt photoinitiator is shown in Formula 1, wherein R1 is a substituted or unsubstituted alkyl or substituted or unsubstituted alkoxy group having 2-9 carbon atoms, and R2, R3, R4, and R5 are independently hydrogen atoms, alkyl groups, halogens, hydroxyl groups, carboxyl groups, amino groups, alkoxy groups, ester groups, nitro groups, and are tetraphenylboron ions, boron tetrafluoride ions, boron hexafluoride ions, phosphorus hexafluoride ions, arsenic hexafluoride ions, tellurium hexafluoride ions, halide ions, perchlorate ions, acetate ions, or trifluorosulfonate ions. The iodonium salt photoinitiator with the structure of this application can be used to prepare treatment-free CTP thermal printing plates, and can improve digital imaging speed and reduce crystals in the precursor of the formed negative lithographic printing plate. At the same time, the prepared treatment-free CTP thermal printing plate has excellent imaging speed and printing durability.

Description

Technical Field

[0001] This invention belongs to the field of thermal printing plates, specifically relating to an iodonium salt photoinitiator and its application in the preparation of treatment-free CTP thermal printing plates. Background Technology

[0002] Since the application of PS plates to offset printing in the 1960s, the offset printing plate-making process has consistently followed the pre-press process of photosensitive film preparation, plate assembly, exposure, and PS plate printing. However, the drawbacks of this plate-making method have gradually become apparent: it is a long process, results in significant dot loss, and produces relatively low print quality, especially causing considerable environmental pollution. To address this situation, in the 1980s, some companies in the United States and Japan began developing Computer-to-Plate (CTP) technology. Currently, CTP technology is rapidly developing and is in the stage of widespread application. The technology is divided into CTP photosensitive plate-making technology and thermal CTP plate-making technology, with thermal CTP plate-making technology being the most mature, stable, and effective plate-making technology at present.

[0003] Post-processing of thermal CTP plate making is divided into two types: chemical treatment and chemical-free treatment. With the development of technology and the increasing environmental protection requirements, chemical-free CTP thermal plates are gradually becoming the mainstream. This technology mainly utilizes the principle of photothermal conversion. When an infrared laser scans and exposes the plate, the infrared-absorbing dye in the scanned area absorbs the infrared laser and converts the light energy into heat energy, causing the infrared dye molecules to transition from the ground state to the excited state. Since the excited state is unstable, the excited infrared dye molecules release all or part of their energy and return to the ground state or a more stable excited state. In this process, the dye molecules release energy in the form of fluorescence, phosphorescence, and radiation. Then, when the wavelength of the radiation light is equal to the absorption wavelength of the free radical initiator, the initiator absorbs the energy released by the dye and decomposes to produce free radicals, thereby initiating the photopolymerization process. The result of photopolymerization is that the monomers and oligomers in the coating form a three-dimensional network copolymer structure. The final result is that the light-exposed areas change from hydrophilic to oleophilic, forming the image areas. The areas not exposed to light remain water-soluble and dissolve and detach on the printing press under the action of dampening solution, ink, or both, exposing the hydrophilic base as the hydrophilic blank area. Because treatment-free plates do not require development or plate-making processes after plate making, and do not require the use of alkaline solutions and chemical solvents, this type of plate is called a treatment-free CTP plate.

[0004] To ensure fast digital imaging speed and good image recognizability, special free radical photoinitiators are typically required for the characteristics of process-free plates. However, a problem with high-volume use of such photoinitiators is the formation of crystals that prevent them from making molecular contact with other components of the photopolymerizable composition in the imageable layer, resulting in lower crosslinking density during infrared radiation exposure. Therefore, more efficient photoinitiator compounds are needed in the photopolymerizable composition to more effectively improve digital imaging speed, provide excellent printing durability, and simultaneously avoid or significantly reduce crystal formation in negative lithography plate precursors.

[0005] Photoinitiators include free radical photoinitiators and cationic photoinitiators. Under suitable conditions, both free radical and cationic photoinitiators can undergo photopolymerization. Free radical photoinitiators are used to initiate the free radical polymerization of unsaturated polyesters, acrylates, and other resins. They are characterized by fast curing speed and wide application, but suffer from drawbacks such as oxygen inhibition, high curing shrinkage, and poor adhesion. Cationic photoinitiators are used to initiate the cationic polymerization of epoxy resins, vinyl ethers, cyclic acetals, lactones, etc. They are characterized by strong adhesion, but suffer from low curing shrinkage and post-curing defects.

[0006] Therefore, existing photoinitiators used for thermal CTP thermal printing plates need to be improved. Summary of the Invention

[0007] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one object of this invention is to provide an iodonium salt photoinitiator and its application in the preparation of treatment-free CTP thermal printing plates. The iodonium salt photoinitiator of this application can be used to prepare treatment-free CTP thermal printing plates, and can improve digital imaging speed and reduce crystals in the resulting negative lithographic printing plate precursor. Simultaneously, the prepared treatment-free CTP thermal printing plate exhibits excellent imaging speed and printing durability.

[0008] In one aspect of the invention, an iodonium salt photoinitiator is provided. According to an embodiment of the invention, the iodonium salt photoinitiator has the general formula shown in Formula 1.

[0009]

[0010] Wherein, R1 is a substituted alkyl or unsubstituted alkyl or substituted alkoxy or unsubstituted alkoxy having 2-9 carbon atoms, preferably R1 is a substituted alkyl or unsubstituted alkyl having 3-5 carbon atoms;

[0011] R2, R3, R4, and R5 are independently hydrogen atoms, alkyl groups, halogens, hydroxyl groups, carboxyl groups, amino groups, alkoxy groups, ester groups, and nitro groups, respectively.

[0012] The ions are tetraphenylboron ion, boron tetrafluoride ion, boron hexafluoride ion, phosphorus hexafluoride ion, arsenic hexafluoride ion, tellurium hexafluoride ion, halide ion, perchlorate ion, acetate ion, or trifluorosulfonate ion, preferably. It is tetraphenylboron ion, boron tetrafluoride ion, or phosphorus hexafluoride ion.

[0013] Therefore, the iodonium salt photoinitiator with the above structure can be used to prepare treatment-free CTP thermal printing plates, and can improve the digital imaging speed and reduce the crystals in the precursor of the formed negative lithographic printing plate. At the same time, the prepared treatment-free CTP thermal printing plate has excellent imaging speed and printing durability.

[0014] According to some embodiments of the present invention, in the general formula of the above-mentioned iodonium salt photoinitiator, R2 and R4 are the same, and R3 and R5 are the same, that is, the general formula structure of the iodonium salt photoinitiator is symmetrical. For example, the structural formula of the iodonium salt photoinitiator includes:

[0015]

[0016] According to some embodiments of the present invention, in the general formula of the above-mentioned iodonium salt photoinitiator, R2 and R5 are the same, and R3 and R4 are the same. For example, the structural formula of the iodonium salt photoinitiator includes:

[0017]

[0018] According to some embodiments of the present invention, in the general formula of the above-mentioned iodonium salt photoinitiator, R4 and R5 are both hydrogen atoms. For example, the structural formula of the iodonium salt photoinitiator includes:

[0019]

[0020]

[0021] In a second aspect, the present invention proposes the application of the above-mentioned iodonium salt photoinitiator in the preparation of treatment-free CTP thermal printing plates.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0024] Figure 1 This is the NMR spectrum of the final product obtained in Example 1;

[0025] Figure 2This is the NMR spectrum of the final product obtained in Example 2;

[0026] Figure 3 This is the NMR spectrum of the final product obtained in Example 8. Detailed Implementation

[0027] The embodiments of the present invention are described in detail below. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. In addition, unless otherwise specified, all reagents used in the following embodiments are commercially available or can be synthesized according to the methods described herein or known to others. For reaction conditions not listed, they are also readily available to those skilled in the art.

[0028] Example 1 (structural formula is) (Note as P1)

[0029] Preparation methods include:

[0030] (1) In a 3L three-necked flask, add 171g potassium iodate, 324g tert-butyl-m-xylene, 306g acetic anhydride and 800ml glacial acetic acid in sequence, and then add a mixed acid solution of (260g concentrated sulfuric acid + 280ml glacial acetic acid) dropwise. Control the temperature at 5-10℃. After the addition is complete, raise the temperature to room temperature and continue stirring the reaction for 10h. Then pour the reaction solution into 1.5L of water and extract it with 1L of petroleum ether to separate the aqueous phase.

[0031] (2) Adding 200g of ammonium chloride aqueous solution to the above aqueous phase resulted in the precipitation of a large amount of solid. After filtration, 171g of pale yellow solid powder was obtained, with a yield of 45.61%. The NMR spectrum of the pale yellow solid powder is shown below. Figure 1 As shown, it can be seen that 1 HNMR: (400MHZ, MeOD)δ(ppm): 1.31(s,18H,-(CH3)3); 2.58(s,12H,-CH3-Ar); 7.39(s,4H,-ArH).

[0032] Example 2 (structural formula is) (Note as P2)

[0033] Preparation methods include:

[0034] In a 3L three-necked flask, 242.5g of the pale yellow solid powder obtained in Example 1, 188g of sodium tetraphenylborate, and 2L of acetone were added sequentially. The mixture was refluxed for 1 hour at room temperature and then filtered to obtain 342g of a white solid, with a yield of 89.06%. The NMR spectrum of this white solid is shown below. Figure 2 As shown, it can be seen that 1HNMR: (400MHZ, CDCl3)δ(ppm):1.25(s,18H,-(CH3)3); 2.10(s,12H,-CH3-Ar); 6.66-7.64(m,24H,-ArH).

[0035] Example 3 (structural formula is) (Note: P3)

[0036] Preparation methods include:

[0037] In a 3L three-necked flask, add 171g potassium iodate, 304g 3-tert-butyltoluene, 306g acetic anhydride, and 800ml glacial acetic acid in sequence. Then, add a mixed acid solution of (260g concentrated sulfuric acid + 280ml glacial acetic acid) dropwise. Control the temperature at 5-10℃. After the addition is complete, raise the temperature to room temperature and continue stirring for 10 hours. Then, pour the reaction solution into 1.5L of water and extract with 1L of petroleum ether to separate the aqueous phase.

[0038] (2) When 200g of an aqueous solution of ammonium chloride was added to the above aqueous phase, a large amount of solid precipitated out. After filtration, 151g of a pale yellow solid powder was obtained, with a yield of 41.21%. The NMR spectrum of the pale yellow solid powder showed that: 1 HNMR: (400MHZ, MeOD)δ(ppm): 1.30(s,18H,-(CH3)3); 2.55(s,6H,-CH3-Ar); 7.40(s,6H,-ArH).

[0039] Example 4 (structural formula is) (Note: P4)

[0040] Preparation methods include:

[0041] (1) In a 3L three-necked flask, add 171g potassium iodate, 304g 3-tert-butyltoluene, 306g acetic anhydride, and 800ml glacial acetic acid in sequence. Then add a mixed acid solution of (260g concentrated sulfuric acid + 280ml glacial acetic acid) dropwise. Control the temperature at 5-10℃. After the addition is complete, raise the temperature to room temperature and continue stirring for 10h. Then pour the reaction solution into 1.5L of water and extract with 1L of petroleum ether to separate the aqueous phase.

[0042] (2) When 300g of sodium tetrafluoroborate aqueous solution was added to the above aqueous phase, a large amount of solid precipitated out. After filtration, 156g of pale yellow solid powder was obtained, with a yield of 41.01%. The NMR spectrum of the pale yellow solid powder showed that: 1 HNMR: (400MHZ, CDCl3)δ(ppm):1.26(s,18H,-(CH3)3); 2.09(s,6H,-CH3-Ar); 6.68-7.61(m,26H,-ArH).

[0043] Example 5 (structural formula is) (Note: P5)

[0044] Preparation methods include:

[0045] (1) In a 3L three-necked flask, add 171g potassium iodate, 298g 1,3-diisopropylbenzene, 306g acetic anhydride and 800ml glacial acetic acid in sequence, and then add a mixed acid solution of (260g concentrated sulfuric acid + 280ml glacial acetic acid) dropwise. Control the temperature at 5-10℃. After the addition is complete, raise the temperature to room temperature and continue stirring for 10h. Then pour the reaction solution into 1.5L of water and extract with 1L of petroleum ether to separate the aqueous phase.

[0046] (2) When 450g of an aqueous solution of sodium hexafluorophosphate was added to the above aqueous phase, a large amount of solid precipitated out. After filtration, 265g of a pale yellow solid powder was obtained, with a yield of 44.56%. The NMR spectrum of the pale yellow solid powder showed that: 1 HNMR: (400MHZ, CDCl3) δ (ppm): 1.24 (d, 24H, -CH3); 2.86 (m, 4H, -CH); 7.05-7.23 (m, 6H, -ArH).

[0047] Example 6 (structural formula is) (Note: P6)

[0048] Preparation methods include:

[0049] (1) In a 3L three-necked flask, add 171g potassium iodate, 324g m-tert-butylphenol, 306g acetic anhydride, and 800ml glacial acetic acid in sequence. Then add a mixed acid solution of (260g concentrated sulfuric acid + 280ml glacial acetic acid) dropwise. Control the temperature at 5-10℃. After the addition is complete, raise the temperature to room temperature and continue stirring for 10h. Then pour the reaction solution into 1.5L of water and extract with 1L of petroleum ether to separate the aqueous phase.

[0050] (2) When 200g of an aqueous solution of ammonium chloride was added to the above aqueous phase, a large amount of solid precipitated out. After filtration, 172g of a pale yellow solid powder was obtained, with a yield of 45.66%. The NMR spectrum of the pale yellow solid powder showed that: 1 HNMR: (400MHZ, CDCl3)δ(ppm): 1.26(s,18H,-(CH3)3); 2.09(s,6H,-CH3-Ar); 9.02(s,2H,-OH).

[0051] Example 7 (the compound has the structural formula shown in Formula 5) (Note: P7)

[0052] Preparation methods include:

[0053] (1) In a 3L three-necked flask, add 171g potassium iodate, 323g m-tert-butylaniline, 306g acetic anhydride, and 800ml glacial acetic acid in sequence. Then add a mixed acid solution of (260g concentrated sulfuric acid + 280ml glacial acetic acid) dropwise. Control the temperature at 5-10℃. After the addition is complete, raise the temperature to room temperature and continue stirring for 10h. Then pour the reaction solution into 1.5L of water and extract with 1L of petroleum ether to separate the aqueous phase.

[0054] (2) When 200g of ammonium bromide aqueous solution was added to the above aqueous phase, a large amount of solid precipitated out. After filtration, 193 g of pale yellow solid powder was obtained, with a yield of 47.91%. The NMR spectrum of the pale yellow solid powder showed that: 1 HNMR: (400MHZ, CDCl3) δ (ppm): 1.26 (s, 18H, - (CH3) 3); 2.09 (s, 6H, -CH3 - Ar); 8.52 (S, 4H, -NH2).

[0055] Example 8 (structural formula is) (Note: P8)

[0056] Preparation methods include:

[0057] (1) In a 250mL three-necked flask, add 23g tetrahydrate and sodium perborate, 40ml glacial acetic acid and 60ml acetic anhydride in sequence. Stir the reaction at room temperature for 1.5h. Then add 13g p-tert-butyliodobenzene, heat to 35℃ and continue the reaction for 1h. Then cool to 0-5℃ and add 37ml tert-butyl-m-xylene. Keep this temperature and continue to add 15ml of concentrated sulfuric acid mixed with glacial acetic acid dropwise. Continue the reaction for 24h. Add to 500ml water and extract twice with petroleum ether to separate the aqueous phase.

[0058] (2) A saturated ammonium chloride aqueous solution was added to the above aqueous phase, resulting in the precipitation of a large amount of solid. After filtration, 9.2 g of product was obtained, with a yield of 40.10%. The NMR spectrum of the obtained product is shown below. Figure 3 As shown, it can be seen that: 1 HNMR: (400MHZ, CDCl3)δ(ppm):1.27(s,18H,-(CH3)3); 2.25(s,6H,-CH3-Ar); 6.67-7.81(m,6H,-ArH).

[0059] Example 9 (structural formula is) (Note: P9)

[0060] Preparation methods include:

[0061] In a 250 mL three-necked flask, 45.7 g of the final product obtained in Example 8, 37.6 g of sodium tetraphenylborate, and 100 mL of acetone were added sequentially. The mixture was refluxed for 1 h at room temperature and filtered to obtain 66.69 g of a white solid, with a yield of 90.01%. The NMR spectrum of the obtained product showed that: 1 HNMR: (400MHZ, CDCl3)δ(ppm): 1.27(s,18H,-(CH3)3); 2.25(s,6H,-CH3-Ar); 6.67-7.81(m,26H,-ArH).

[0062] Example 10 (structural formula is) (Note: P10)

[0063] Preparation methods include:

[0064] (1) In a 250mL three-necked flask, add 23g tetrahydrate and sodium perborate, 40ml glacial acetic acid and 60ml acetic anhydride in sequence. Stir the reaction at room temperature for 1.5h. Then add 13g p-tert-butyliodobenzene, heat to 35℃ and continue the reaction for 1h. Then cool to 0-5℃ and add 35ml m-tert-butylm-toluene. Keep this temperature and continue to add 15ml of concentrated sulfuric acid mixed with glacial acetic acid dropwise. Continue the reaction for 24h. Add to 500ml water and extract twice with petroleum ether to separate the aqueous phase.

[0065] (2) A saturated ammonium chloride aqueous solution was added to the above aqueous phase, and a large amount of solid precipitated out. After filtration, 9.2 g of product was obtained, with a yield of 40.58%. The NMR spectrum of the obtained product showed that: 1 HNMR: (400MHZ, CDCl3)δ(ppm):1.27(s,18H,-(CH3)3); 2.27(s,3H,-CH3-Ar); 6.67-7.81(m,7H,-ArH).

[0066] Example 11 (structural formula is) (Note: P11)

[0067] Preparation methods include:

[0068] (1) In a 250mL three-necked flask, add 23g tetrahydrate and sodium perborate, 40ml glacial acetic acid and 60ml acetic anhydride in sequence. Stir the reaction at room temperature for 1.5h. Then add 13g p-tert-butyliodobenzene, heat to 35℃ and continue the reaction for 1h. Then cool to 0-5℃ and add 35ml m-tert-butylm-toluene. Keep this temperature and continue to add 15ml of concentrated sulfuric acid mixed with glacial acetic acid dropwise. Continue the reaction for 24h. Add to 500ml water and extract twice with petroleum ether to separate the aqueous phase.

[0069] (2) When excess sodium tetrafluoroborate aqueous solution was added to the above aqueous phase, a large amount of solid precipitated out. After filtration, 12.5 g of product was obtained, with a yield of 47.58%. The NMR spectrum of the obtained product showed that: 1 HNMR: (400MHZ, CDCl3)δ(ppm):1.27(s,18H,-(CH3)3); 2.27(s,3H,-CH3-Ar); 6.67-7.81(m,7H,-ArH).

[0070] Example 12 (structural formula is) (Note: P12)

[0071] Preparation methods include:

[0072] (1) In a 250mL three-necked flask, add 23g tetrahydrate and sodium perborate, 40ml glacial acetic acid and 60ml acetic anhydride in sequence. Stir the reaction at room temperature for 1.5h. Then add 13g p-tert-butyliodobenzene, heat to 35℃ and continue the reaction for 1h. Cool down to 0-5℃ and add 35ml diisopropylbenzene. Keep this temperature and continue to add 15ml concentrated sulfuric acid and glacial acetic acid mixed acid solution. Continue the reaction for 24h. Add to 500ml water and extract twice with petroleum ether to separate the aqueous phase.

[0073] (2) When excess sodium hexafluorophosphate aqueous solution was added to the above aqueous phase, a large amount of solid precipitated out. After filtration, 14.5 g of product was obtained, with a yield of 48.2%. The NMR spectrum of the obtained product showed that: 1 HNMR: (400MHZ, CDCl3) δ (ppm): 1.25 (d, 12H, - (CH3) 2); 1.27 (s, 9H, - (CH3) 3); 2.86 (m, 2H, -CH-Ar); 6.67-7.81 (m, 7H, -ArH).

[0074] Example 13 (Structural Formula) (Note: P13)

[0075] Preparation methods include:

[0076] (1) In a 250mL three-necked flask, add 23g tetrahydrate and sodium perborate, 40ml glacial acetic acid and 60ml acetic anhydride in sequence. Stir the reaction at room temperature for 1.5h. Then add 13g p-tert-butyliodobenzene, heat to 35℃ and continue the reaction for 1h. Cool down to 0-5℃ and add 10g m-tert-butylphenol. Keep this temperature and continue to add 15ml of concentrated sulfuric acid mixed with glacial acetic acid dropwise. Continue the reaction for 24h. Add to 500ml water and extract twice with petroleum ether to separate the aqueous phase.

[0077] (2) When excess sodium perchlorate aqueous solution was added to the above aqueous phase, a large amount of solid precipitated out. After filtration, 12.2 g of product was obtained, with a yield of 47.8%. The NMR spectrum of the obtained product showed that: 1 HNMR: (400MHZ, CDCl3) δ (ppm): 1.27 (s, 18H, - (CH3) 3); 6.67-7.81 (m, 7H, -ArH); 9.21 (s, 1H, -OH).

[0078] Example 14 (structural formula is) (Note: P14)

[0079] Preparation methods include:

[0080] (1) In a 250mL three-necked flask, add 23g tetrahydrate and sodium perborate, 40ml glacial acetic acid and 60ml acetic anhydride in sequence. Stir the reaction at room temperature for 1.5h. Then add 13g p-tert-butyliodobenzene, heat to 35℃ and continue the reaction for 1h. Cool down to 0-5℃ and add 38ml m-tert-butylaniline. Keep this temperature and continue to add 15ml of a mixed acid solution of concentrated sulfuric acid and glacial acetic acid. Continue the reaction for 24h. Add to 500ml water and extract twice with petroleum ether to separate the aqueous phase.

[0081] (2) When excess sodium bromide aqueous solution was added to the above aqueous phase, a large amount of solid precipitated out. After filtration, 11.7 g of product was obtained, with a yield of 47.6%. The NMR spectrum of the obtained product showed that: 1 HNMR: (400MHZ, CDCl3) δ (ppm): 1.27 (s, 18H, - (CH3) 3); 6.67-7.81 (m, 7H, -ArH); 8.46 (s, 2H, -NH2).

[0082] Example 15 (structural formula is formula) (Note: P15)

[0083] Preparation methods include:

[0084] (1) In a 250mL three-necked flask, add 23g tetrahydrate and sodium perborate, 40ml glacial acetic acid and 60ml acetic anhydride in sequence. Stir the reaction at room temperature for 1.5h. Then add 13g p-tert-butyliodobenzene, heat to 35℃ and continue the reaction for 1h. Cool down to 0-5℃ and add 40ml m-isopropyltoluene. Maintain this temperature and continue to add 15ml of a mixed acid solution of concentrated sulfuric acid and glacial acetic acid. Continue the reaction for 24h. Add to 500ml water and extract twice with petroleum ether to separate the aqueous phase.

[0085] (2) When excess sodium bromide aqueous solution was added to the above aqueous phase, a large amount of solid precipitated out. After filtration, 11.6 g of product was obtained, with a yield of 46.6%. The NMR spectrum of the obtained product showed that: 1 HNMR: (400MHZ, CDCl3)δ(ppm): 1.23(d,6H,-(CH3)2); 1.27(s,9H,-(CH3)3); 2.88(s.3H,-CH3-Ar); 6.67-7.81(m,7H,-ArH).

[0086] Referring to Chinese Patent CN 201010614939.9, the substrate was prepared as follows: an A1050 rolled aluminum plate with a purity of 99.5% and a thickness of 0.3 mm was etched in a 5 wt% sodium hydroxide aqueous solution at 70°C for 20 seconds. After rinsing with running water, it was immediately neutralized with a 1 wt% nitric acid aqueous solution, and then etched in a 1 wt% hydrochloric acid aqueous solution at 40°C with a sinusoidal alternating current at 50 A / dm². 2 The surface was roughened by electrolysis at a current density of 16 seconds, followed by neutralization with a 5 wt% sodium hydroxide aqueous solution at 40°C for 10 seconds, then washed with water, and finally subjected to electrolysis with a 20 wt% sulfuric acid aqueous solution at 30°C at 15 A / dm³. 2 The current density was adjusted, and anodizing was performed for 20 seconds, followed by water washing. Then, the pores were sealed with a 5wt% sodium silicate aqueous solution at 80℃ for 18 seconds, followed by water washing and drying to obtain the substrate. The average thickness of the centerline of this substrate was 0.5 μm, and the oxide film weight was 3.0 g / dm². 2 .

[0087] Photosensitive layer coating: The photosensitive liquid with the following composition is applied by extrusion coating onto the substrate obtained above, and then dried at 100°C for 60 seconds to obtain a dry weight of 10 mg / dm³. 2 The coating;

[0088] The photosensitive solution comprises: a polymer with structure A, a polymer with structure B, a polyester acrylate prepolymer, polypentanetetrafluoroethylene acrylate, an iodonium salt photoinitiator, an infrared dye, BYK-333, and 1-methoxy-2-propanol, wherein...

[0089] The final products obtained in Examples 1-14 were used as iodonium salt photoinitiators to prepare photosensitive solutions, and the compositions are shown in Table 1.

[0090] Table 1

[0091]

[0092]

[0093] In Table 1 above: Structural formula of polymer A1:

[0094] Polymer A2 structural formula

[0095]

[0096] The structural formula of initiator P16 used in Comparative Example 1:

[0097]

[0098] Initiator P17 used in Comparative Example 2:

[0099]

[0100] The structural formula of infrared dye R:

[0101]

[0102] The plates obtained using the photosensitive solutions from Experimental Examples 1-15 and Comparative Examples 1-2 were first tested on a Kodak Allwinner thermal CTP plate-making machine using its built-in test strips to determine the minimum exposure energy. Then, exposure was performed at an appropriate energy. Finally, the plates were directly mounted onto a Heidelberg SM52 printing press, the press was turned on, and the entire plate was dampened with dampening solution for 10 seconds before paper was fed and printing began. The performance is listed in Table 2 below.

[0103] Furthermore, the plate samples obtained in each embodiment underwent accelerated aging for 7 days in a constant temperature chamber at 40°C and 80% RH. These plate samples were then imaged using a Kodak Allwinner thermal CTP plate-making machine with appropriate energy. Their performance is listed in Table 3 below.

[0104] Table 2

[0105]

[0106] Table 3

[0107]

[0108]

[0109] Remark:

[0110] 1. Crystallization is a 5-point rating of the amount of crystals observed after high temperature and high humidity testing, where "5" indicates no crystals were observed, "1" indicates many crystals were observed, "2" indicates a relatively large number of crystals were observed, and "3" indicates some crystals were observed.

[0111] 2. As described above, the plate samples obtained in each embodiment were imaged and exposed using a Kodak CTP plate-making machine. The color difference between the exposed and unexposed areas was measured using an X-Rite spectral densitometer. The Euclidean distance of the measured L*a*b values ​​was calculated, ΔE=[(ΔL)] 2 +(△a) 2 +(△b) 2 ] 1 / 2 In the table, "+" indicates that △E > 8; "0" indicates that △E is between 5 and 8; and "-" indicates that △E < 5.

[0112] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0113] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An iodonium salt photoinitiator characterized in that, The structural formula of the iodonium salt photoinitiator is shown below, 。 2. Use of the iodonium salt photoinitiator described in claim 1 in the preparation of a processless CTP thermal sensitive printing plate.

Images