Cold rolling method for high-precision CTP printing plate base

Abstract

The invention relates to the technical field of preparation of high-precision CTP printing plate bases, in particular to a cold rolling method of a high-precision CTP printing plate base, which is characterized in that cold rolling reduction pass distribution is as follows: the thickness of 2.5 mm is rolled to the thickness of 1.1 mm in the first pass, the thickness of 1.1 mm is rolled to the thickness of 0.50 mm in the second pass, and the thickness of 0.50 mm is rolled to the thickness of (0.25-0.28) mm in the third pass for cold rolling. The method has the advantages of effectively reducing cold rolling passes, improving the cold rolling pass machining rate, improving the cold rolling production efficiency, reducing the production cost and the like.

Description

Technical Field

[0001] The invention relates to the technical field of high-precision CTP printing plate preparation, and specifically to a cold rolling method for a high-precision CTP printing plate that effectively reduces the number of cold rolling passes, improves the cold rolling pass processing rate, improves the cold rolling production efficiency, and reduces the production cost. Background Art

[0002] As we all know, CTP (computer to plate) technology has gradually replaced the traditional analog plate-making method due to its advantages of digitalization, high efficiency, high quality, simplicity, and environmental protection, and has become a way for printing companies to achieve technological upgrades. At present, hot-rolled blank 1050 alloy or hot-rolled blank 1052 alloy is commonly used in the market to produce printing plate base blanks. The present invention uses 1050H alloy blanks.

[0003] The traditional cold rolling method generally requires no less than 4 cold rolling passes to roll a 0.263mm plate base, such as cold rolling 2.5-1.3-0.75-0.40-0.263, and the cold rolling speed is slow, such as 300m / min for the first pass, 500m / min for the second pass, 700m / min for the third pass, and 900m / min for the fourth pass. Reducing the number of cold rolling passes, increasing the pass processing rate, and increasing the cold rolling speed will lead to surface quality defects such as pine tree branch patterns, water ripples, sticking, scratches, small white spots, and large rib waves or medium waves + rib waves. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies of the above-mentioned prior art and to provide a cold rolling method for a high-precision CTP printing plate substrate which can effectively reduce the number of cold rolling passes, improve the cold rolling pass processing rate, improve the cold rolling production efficiency, and reduce the production cost.

[0005] The technical solution adopted by the present invention to solve its technical problem is: A cold rolling method for a high-precision CTP printing plate substrate, characterized in that the cold rolling method comprises the following steps: (1) Take a 2.5 mm billet coil, completely recrystallize and anneal it, and then cool it to below 45°C; (2) cold rolling the billet coil processed in step (1) in the following passes: in the first pass, the thickness of 2.5 mm is rolled down to 1.1 mm, in the second pass, the thickness of 1.1 mm is rolled down to 0.50 mm, and in the third pass, the thickness of 0.50 mm is rolled down to (0.25-0.28) mm; (3) In step (2): the interval between two adjacent passes is greater than or equal to 24 hours, the inlet temperature of the aluminum coil of the first pass is ≤45°C, the inlet temperature of the second and third passes is ≤60°C, and the outlet temperature of the aluminum coil of the second and third passes is ≤100°C; (3) In step (2): the surface roughness Ra of the working roll used in the first and second passes is 0.28 to 0.38 µm, the surface roughness Ra of the working roll used in the third pass is 0.18 to 0.26 µm, and the surface roughness Ra of the backup rolls in the three passes is 1.0 to 1.2 µm.

[0006] (4) During the rolling process in step (2), the concentration ratio of the process lubricant additive is: alcohol 5-8%, ester 2.5-4%; (5) In step (2), the process oil injection pressure of the three passes is adjusted to 5-7 bar, and the process oil injection flow rate of the three passes is adjusted to 40-100%; (6) In step (2), the given tensions of each pass are: the first pass entrance tension is 14±2MPa, and the exit tension is 28±2MPa; the second pass entrance tension is 24±2MPa, and the exit tension is 28±2MPa; the third pass entrance tension is 24±2MPa, and the exit tension is 26±2MPa; (7) In step (2), the rolling speed of each pass is: the rolling speed of the first pass is 400-590 m / min, the rolling speed of the second pass is 800-1100 m / min, and the rolling speed of the third pass is 1000-1400 m / min.

[0007] The process oil injection flow rate in step (5) of the present invention is: 90% in the first pass, 70% in the second pass, and 55% in the third pass.

[0008] In the step (4) of the present invention, the alcohol in the process lubricant additive is dodecanol and tetradecanol, the ester is hexadecyl ester, and the ratio of dodecanol to tetradecanol is 1:3.

[0009] The process lubricant additive in step (4) of the present invention also includes a surfactant, an antioxidant, an antistatic agent, and a rolling oil compatibility agent. The additive concentration ratio of the surfactant, antioxidant, antistatic agent, and rolling oil compatibility agent is: surfactant 0.5-0.7%, antioxidant 0.2-0.5%, antistatic agent 0.1-0.3%, rolling oil compatibility agent 0.8-1.0%.

[0010] The surfactant of the invention adopts fatty acid glyceride, the antioxidant adopts 2,6-di-tert-butyl-p-cresol, the antistatic agent adopts glyceryl monostearate, and the rolling oil compatibility agent adopts polyether ester.

[0011] In step (3) of the present invention, the surfaces of the working rolls of the first pass, the working rolls of the second pass and the working rolls of the third pass are respectively plated with chrome layers, the thickness of the chrome layer of the first pass is 0.2 mm, the hardness is HS97, the thickness of the chrome layer of the second pass is 0.22 mm, the hardness is HS98, the thickness of the chrome layer of the third pass is 0.25 mm, and the hardness is HS99. In step (5) of the present invention, the process oil injection flow rate is: 90% for the first pass, 70% for the second pass, and 55% for the third pass.

[0012] The present invention adopts the above method, and after being processed by the above cold rolling method, the obtained high-precision CTP printing plate base strip has a thickness of 0.263±0.002mm, a straightness of 15IU, a clean and smooth surface, uniform color, and a transverse roughness Ra of 0.18µm. After conventional cleaning, trimming, stretching and straightening, it meets customer requirements. Under the premise of maintaining high precision and high quality of cold-rolled products (clean and smooth surface, uniform color, transverse roughness Ra of 0.15-0.28µm, thickness tolerance ≤±0.003mm, straightness ≤20IU), one cold rolling pass is reduced, the cold rolling speed is increased, the production efficiency is increased, and the cold rolling production cost is saved by more than 25%. The present invention has the advantages of effectively reducing the number of cold rolling passes, increasing the cold rolling pass processing rate, increasing the cold rolling production efficiency, and reducing the production cost. DETAILED DESCRIPTION

[0013] The present invention is further described below: A cold rolling method for a high-precision CTP printing plate substrate, characterized in that the cold rolling method comprises the following steps: (1) Take a 2.5 mm billet coil, completely recrystallize and anneal it, and then cool it to below 45°C; (2) cold rolling the billet coil processed in step (1) in the following passes: in the first pass, the thickness of 2.5 mm is rolled down to 1.1 mm, in the second pass, the thickness of 1.1 mm is rolled down to 0.50 mm, and in the third pass, the thickness of 0.50 mm is rolled down to (0.25-0.28) mm; (3) In step (2): the interval between two adjacent passes is greater than or equal to 24 hours, the inlet temperature of the aluminum coil of the first pass is ≤45°C, the inlet temperature of the second and third passes is ≤60°C, and the outlet temperature of the aluminum coil of the second and third passes is ≤100°C; (3) In step (2): the surface roughness Ra of the working roll used in the first and second passes is 0.28 to 0.38 µm, the surface roughness Ra of the working roll used in the third pass is 0.18 to 0.26 µm, and the surface roughness Ra of the backup rolls in the three passes is 1.0 to 1.2 µm.

[0014] (4) During the rolling process in step (2), the concentration ratio of the process lubricant additive is: alcohol 5-8%, ester 2.5-4%; (5) In step (2), the process oil injection pressure of the three passes is adjusted to 5-7 bar, and the process oil injection flow rate of the three passes is adjusted to 40-100%; (6) In step (2), the given tensions of each pass are: the first pass entrance tension is 14±2MPa, and the exit tension is 28±2MPa; the second pass entrance tension is 24±2MPa, and the exit tension is 28±2MPa; the third pass entrance tension is 24±2MPa, and the exit tension is 26±2MPa; (7) In step (2), the rolling speed of each pass is: the rolling speed of the first pass is 400-590 m / min, the rolling speed of the second pass is 800-1100 m / min, and the rolling speed of the third pass is 1000-1400 m / min.

[0015] Furthermore, in step (5), the process oil injection flow rate is: 90% in the first pass, 70% in the second pass, and 55% in the third pass.

[0016] Furthermore, in the step (4), the alcohol in the process lubricant additive is dodecanol and tetradecanol, the ester is hexadecyl ester, and the ratio of dodecanol to tetradecanol is 1:3.

[0017] Furthermore, the process lubricant additive in step (4) further includes a surfactant, an antioxidant, an antistatic agent, and a rolling oil compatibility agent, and the additive concentration ratio of the surfactant, antioxidant, antistatic agent, and rolling oil compatibility agent is: surfactant 0.5-0.7%, antioxidant 0.2-0.5%, antistatic agent 0.1-0.3%, rolling oil compatibility agent 0.8-1.0%.

[0018] Furthermore, the surfactant is fatty acid glyceride, the antioxidant is 2,6-di-tert-butyl-p-cresol, the antistatic agent is glyceryl monostearate, and the rolling oil compatibility agent is polyether ester.

[0019] Furthermore, in the step (3), the surfaces of the working rolls of the first pass, the working rolls of the second pass, and the working rolls of the third pass are respectively plated with chrome layers, the thickness of the chrome layer of the first pass is 0.2 mm, and the hardness is HS97, the thickness of the chrome layer of the second pass is 0.22 mm, and the hardness is HS98, and the thickness of the chrome layer of the third pass is 0.25 mm, and the hardness is HS99.

[0020] The present invention has the following advantages: under the premise of maintaining high precision and high quality of cold-rolled products (clean and smooth surface, uniform color, transverse roughness Ra of the strip is 0.15-0.28µm, thickness tolerance ≤±0.003mm, straightness ≤20IU), one cold rolling pass is reduced, the cold rolling speed is increased, the production efficiency is improved, and the cold rolling production cost is saved by more than 25%.

[0021] The principle analysis of the method used in the present invention is as follows: 1. Roughness control between rollers. The roughness of the working roller required for rolling high-precision CTP printing plate base strip is relatively low, and a certain roughness must be reached so that the surface roughness of the roller can be "copied" to the surface of the strip during rolling. If the roughness of the working roller is too small, it is easy to slip during high-speed rolling; if the roughness of the working roller is too large, the surface roughness of the strip will exceed the range required by the customer; and in addition to the surface of the aluminum strip, the support roller is also in direct contact with the working roller, and there are strict requirements for the matching of the surface roughness of the support roller. Because if the surface roughness of the support roller is too large, the contact friction between the working roller and the support roller will be too large. When the rollers rotate with each other, the contact friction between the roller surfaces is too large, and the working roller and the support roller will be scratched, resulting in scratches on the surface of the aluminum strip, and the uniformity of the surface roughness will be destroyed. If the surface roughness of the support roller is too small, the surface of the working roller and the support roller will easily slip during rolling, damaging the roller surface, and the scratches on the roller surface will be transferred to the surface of the aluminum strip. The roughness of the working roll and the support roll provided by the present invention will not produce defects such as scratches when the rollers interact with each other, and can greatly improve the uniformity of the surface roughness of the aluminum strip.

[0022] 2. Optimize the lubrication state of the upper and lower surfaces during the cold rolling process. When the aluminum strip is rolled, the friction and lubrication between the rollers and the aluminum strip work together. If the lubrication is excessive, slipping will occur in the roller gap, causing surface defects such as chatter marks and scratches; if the lubrication is insufficient, surface defects such as pine tree branch patterns, water ripples, sticking, and small white spots will appear; the process lubricant must simultaneously meet the requirements of the high-speed cold rolling process for lubrication, cooling, and cleaning functions; the rolling oil additive ratio provided by the present invention can ensure the smooth progress of the cold rolling process and that the rolled strip has excellent surface quality, thickness accuracy, and plate straightness.

[0023] 3. Process oil injection pressure and flow control. The main functions of process oil in the rolling process of aluminum strip are cooling, lubrication and cleaning. If the process oil injection pressure and flow are too large, the cooling capacity will be too large, causing the roller profile to change, resulting in the deterioration of the cold-rolled outlet strip shape. When the process oil injection pressure and flow are too small, poor lubrication, surface defects, abnormal plate shape and the like will occur. The process oil injection pressure and injection flow values ​​provided by the present invention can well meet the various requirements of high-precision CTP printing plate base strip cold rolling.

[0024] 4. Rolling pass reduction distribution. The first two passes focus on production efficiency and use the largest possible pass processing rate; the third pass focuses on surface quality and plate flatness control and uses a relatively smaller pass processing rate. If the pass processing rate is too large, it will cause surface defects such as pine tree branch patterns, water ripples, sticking, small white spots, and poor plate shape. If the pass processing rate is too small, the production efficiency is low and the production cost is high.

[0025] 5. Optimize the entrance and exit tension of each pass. In rolling production, applying tension is an important means to adjust the plate shape and ensure the smooth progress of the rolling process. The effect of tension changes the stress state of the deformation zone in the roll gap, reduces the longitudinal compressive stress, and thus reduces the unit pressure during rolling. The change in tension affects the thermal convexity of the roll, the rolling pressure distribution, and the lateral flow of the metal. The tension affects the thermal convexity of the roll, especially the entrance tension. Increasing the entrance and exit tension can reduce the lateral deformation of the metal, reduce the exit thickness, and make the cross-section of the rolled piece more uniform. However, the tension cannot be too large. If the exit tension is too large, first, the contact pressure between the exit strip and the plate roller is too large, which is easy to scratch the lower surface of the strip. Second, it is not conducive to observing the exit plate shape, and third, it is easy to break the strip. If the entrance tension is too large, the forward slip value may be negative, the strip slips in the roll gap, and it is also easy to cause the strip to break. The given entrance tension and exit tension of each pass provided by the present invention can effectively reduce the rolling pressure and avoid surface scratches, slippage, and strip breakage.

[0026] 6. Optimize the temperature of the cold-rolled strip. If the temperature of the cold-rolled strip is too high, the temperature in the cold-rolled roll gap will be too high, the lubrication performance of the process oil will decrease, and surface quality defects will occur. Secondly, the roll shape will change, resulting in poor plate shape. Thirdly, the surface of the strip is easily scratched by the roll system. To achieve high-speed cold rolling, it is necessary to reasonably limit the temperature of the aluminum strip coil. Therefore, the present invention provides a limit on the temperature of the aluminum coil at the entrance of each cold rolling pass and the interval cooling time between adjacent passes, which can effectively avoid the above-mentioned disadvantages.

[0027] 7. The alcohol is dodecanol and tetradecanol, and the ester is hexadecyl ester. The ratio of dodecanol to tetradecanol is 1:3. Dodecanol increases the overall lubrication performance, and tetradecanol and hexadecyl ester can ensure the support strength of the formed oil film, ensuring that after reducing one rolling pass, the support strength of the oil film can make the rolling effect better.

[0028] 8. The role of surfactants: it can ensure the activity of alcohol and ester, make them fully mixed and evenly dispersed, and thus form an oil film with higher support strength. The role of antioxidants: rolling base oil is mainly an alkane structure, and oxidation problems will occur after long-term use. The addition of antioxidants can effectively improve the antioxidant ability of rolling oil and extend the service life of rolling oil. The role of antistatic agents: improve the conductivity of rolling oil, reduce static electricity accumulation caused by internal friction, and reduce fire hazards. The role of rolling oil compatibility agents: improve the compatibility of alcohol ester additives with base oils, promote the uniform dispersion of alcohol ester additives in the base oil, and make the rolling oil have stable and uniform lubrication properties, which can effectively reduce rolled plate surface defects (such as uneven plate shape, herringbone patterns, tire marks, etc.).

[0029] 9. The surfaces of the working rolls of the first pass, the second pass and the third pass are respectively plated with chrome layers. The chrome layers increase the hardness of the working roll surfaces, making the rolling effect better. Moreover, the thickness and hardness of the chrome layers on the working roll surfaces of the first pass, the second pass and the third pass are different, and are determined according to the rolling ratios of different passes, which can ensure better rolling effects.

[0030] The production method of high-precision CTP printing plate is as follows: 2.5mm billet coil → complete recrystallization annealing → cold rolling → cleaning, trimming, stretching and straightening.

[0031] The high-precision CTP printing plate substrate high-processing rate high-speed cold rolling method of the present invention adopts a four-roll irreversible cold rolling mill to perform cold rolling on the aluminum billet. The required surface roughness of the working roll is 0.28-0.38µm for the first and second passes, 0.18-0.26µm for the third pass, and the surface roughness of the support roll is 1.0-1.2µm.

[0032] Embodiment 1: The 2.5mm thick aluminum coil, which has been completely recrystallized and annealed and cooled to below 45°C, is subjected to high-precision CTP printing plate base high-processing rate high-speed cold rolling. The method and process parameters are as follows: (1) Cold rolling pass distribution: 2.5-1.1-0.50-0.263.

[0033] (2) The temperature of the aluminum coil at the entrance of each pass and the cooling time between adjacent passes: The interval between two adjacent passes is 24 hours. The temperature of the aluminum coil at the entrance of the first pass is 35°C, the temperature of the aluminum coil at the entrance of the remaining passes is ≤60°C, and the temperature of the aluminum coil at the exit is ≤100°C.

[0034] (3) Roll surface roughness control: the working roll surface roughness Ra of the first and second passes is 0.28µm, the third pass Ra is 0.18µm, and the support roll surface roughness Ra is 1.0µm; (4) Adjust the ratio of process lubricant additives: alcohol 7%, ester 3.5%; (5) Adjust the process oil injection pressure to 6 bar, process oil injection flow rate: 90% for the first pass, 70% for the second pass, and 55% for the third pass (6) The given tension for each pass is: the entrance tension of the first pass is 12 MPa, and the exit tension is 26 MPa; the entrance tension of the second pass is 22 MPa, and the exit tension is 26 MPa; the entrance tension of the third pass is 22 MPa, and the exit tension is 24 MPa.

[0035] (7) Rolling speed of each pass: 400 m / min for the first pass, 800 m / min for the second pass, and 1000 m / min for the third pass.

[0036] The alcohol in the process lubricant additive is dodecanol and tetradecanol, the ester is hexadecyl ester, and the ratio of dodecanol to tetradecanol is 1:3.

[0037] The process lubricant additive in the above step (4) also includes a surfactant, an antioxidant, an antistatic agent, and a rolling oil compatibility agent. The additive concentration ratio of the surfactant, antioxidant, antistatic agent, and rolling oil compatibility agent is: surfactant 0.5-0.7%, antioxidant 0.2-0.5%, antistatic agent 0.1-0.3%, rolling oil compatibility agent 0.8-1.0%.

[0038] The surfactant is fatty acid glyceride, the antioxidant is 2,6-di-tert-butyl-p-cresol, the antistatic agent is glyceryl monostearate, and the rolling oil compatibility agent is polyether ester.

[0039] In the above step (3), the surfaces of the working rolls of the first pass, the working rolls of the second pass and the working rolls of the third pass are respectively plated with chrome layers, the thickness of the chrome layer of the first pass is 0.2 mm, the hardness is HS97, the thickness of the chrome layer of the second pass is 0.22 mm, the hardness is HS98, and the thickness of the chrome layer of the third pass is 0.25 mm, the hardness is HS99.

[0040] After the above-mentioned cold rolling method, the obtained high-precision CTP printing plate base strip has a thickness of 0.263±0.002mm, a straightness of 15IU, a clean and smooth surface, and a uniform color. The transverse roughness Ra of the strip is 0.18µm. After conventional cleaning, trimming, stretching and straightening, it meets customer requirements.

[0041] Embodiment 2: The 2.5mm thick aluminum coil, which has been completely recrystallized and annealed and cooled to below 45°C, is subjected to high-precision CTP printing plate base high-processing rate high-speed cold rolling. The method and process parameters are as follows: (1) Cold rolling pass distribution: 2.5-1.1-0.50-0.263 (2) The temperature of the aluminum coil at the entrance of each pass and the cooling time between adjacent passes: The interval between two adjacent passes is 48 hours, the temperature of the aluminum coil at the entrance of the first pass is 45°C, the temperature of the aluminum coil at the entrance of the remaining passes is ≤60°C, and the temperature of the aluminum coil at the exit is ≤100°C.

[0042] (3) Roller surface roughness control: the working roll surface roughness Ra of the first and second passes is 0.38µm, the third pass Ra is 0.26µm, and the support roll surface roughness Ra is 1.2µm; (4) Adjust the ratio of process lubricant additives: alcohol 7%, ester 3.5%; (5) Adjust the process oil injection pressure to 6 bar, process oil injection flow rate: 90% for the first pass, 70% for the second pass, and 55% for the third pass (6) The given tension for each pass is: the entrance tension of the first pass is 16 MPa, and the exit tension is 30 MPa; the entrance tension of the second pass is 26 MPa, and the exit tension is 30 MPa; the entrance tension of the third pass is 26 MPa, and the exit tension is 28 MPa.

[0043] (7) Rolling speed of each pass: 590 m / min for the first pass, 1100 m / min for the second pass, and 1400 m / min for the third pass.

[0044] The alcohol in the process lubricant additive is dodecanol and tetradecanol, the ester is hexadecyl ester, and the ratio of dodecanol to tetradecanol is 1:3.

[0045] The process lubricant additive in the above step (4) also includes a surfactant, an antioxidant, an antistatic agent, and a rolling oil compatibility agent. The additive concentration ratio of the surfactant, antioxidant, antistatic agent, and rolling oil compatibility agent is: surfactant 0.5-0.7%, antioxidant 0.2-0.5%, antistatic agent 0.1-0.3%, rolling oil compatibility agent 0.8-1.0%.

[0046] The surfactant is fatty acid glyceride, the antioxidant is 2,6-di-tert-butyl-p-cresol, the antistatic agent is glyceryl monostearate, and the rolling oil compatibility agent is polyether ester.

[0047] In the above step (3), the surfaces of the working rolls of the first pass, the working rolls of the second pass and the working rolls of the third pass are respectively plated with chrome layers, the thickness of the chrome layer of the first pass is 0.2 mm, the hardness is HS97, the thickness of the chrome layer of the second pass is 0.22 mm, the hardness is HS98, and the thickness of the chrome layer of the third pass is 0.25 mm, the hardness is HS99.

[0048] After the above-mentioned cold rolling method, the obtained high-precision CTP printing plate base strip has a thickness of 0.263±0.003mm, a straightness of 16IU, a smooth surface, and uniform color. The transverse roughness Ra of the strip is 0.22µm. After conventional cleaning, trimming, stretching and straightening, it meets customer requirements.

[0049] Comparative Example 1: This comparative example adopts conventional methods and parameters in the art, and cold-rolls a 2.5 mm thick billet aluminum coil that has been completely recrystallized and annealed and cooled, and the method and process parameters are as follows: (1) Cold rolling pass distribution: 2.5-1.3-0.75-0.40-0.263.

[0050] (2) The temperature of the aluminum coil at the entrance of each pass and the cooling time between adjacent passes: The interval between two adjacent passes is 4 hours, and the temperature of the aluminum coil at the entrance of the first pass is 45°C.

[0051] (3) Roller surface roughness control: the working roll surface roughness Ra of the first and second passes is 0.28µm, the third pass Ra is 0.18µm, and the support roll surface roughness Ra is 1.1µm; (4) Adjust the ratio of process lubricant additives: alcohol 7%, ester 2% (5) Adjust the process oil injection pressure to 6 bar, process oil injection flow rate: 90% for the first pass, 70% for the second pass, 55% for the third pass, and 50% for the fourth pass (6) The given tension for each pass is: the entrance tension of the first pass is 12 MPa, and the exit tension is 20 MPa; the entrance tension of the second pass is 17 MPa, and the exit tension is 28 MPa; the entrance tension of the third pass is 20 MPa, and the exit tension is 28 MPa; the entrance tension of the fourth pass is 20 MPa, and the exit tension is 26 MPa.

[0052] (7) Rolling speed of each pass: 300 m / min for the first pass, 500 m / min for the second pass, 700 m / min for the third pass, and 900 m / min for the fourth pass.

[0053] After the above cold rolling method, the obtained high-precision CTP printing plate base strip has a thickness of 0.263±0.002mm, a straightness of 15IU, a basically clean and smooth surface, uniform color, and a transverse roughness Ra of 0.18µm. After conventional cleaning, trimming, stretching and straightening, it meets customer requirements. The disadvantage is that there are more cold rolling passes, low production efficiency and high cost.

[0054] Comparative Example 2: This comparative example adopts conventional methods and parameters in the art, and cold-rolls a 2.5 mm thick billet aluminum coil that has been completely recrystallized and annealed and cooled, and the method and process parameters are as follows: (1) Cold rolling pass distribution: 2.5-1.0-0.45-0.263.

[0055] (2) The temperature of the aluminum coil at the entrance of each pass and the cooling time between adjacent passes: The interval between two adjacent passes is 4 hours, and the temperature of the aluminum coil at the entrance of the first pass is 40°C.

[0056] (3) Roller surface roughness control: the working roll surface roughness Ra of the first and second passes is 0.45µm, the third pass Ra is 0.35µm, and the support roll surface roughness Ra is 1.3µm; (4) Adjust the ratio of process lubricant additives: alcohol 7%, ester 2% (5) Adjust the process oil injection pressure to 6 bar, process oil injection flow rate: 90% for the first pass, 70% for the second pass, and 55% for the third pass (6) The given tension for each pass is: the entrance tension of the first pass is 12 MPa, and the exit tension is 20 MPa; the entrance tension of the second pass is 18 MPa, and the exit tension is 35 MPa; the entrance tension of the third pass is 20 MPa, and the exit tension is 35 MPa.

[0057] (7) Rolling speed of each pass: 500 m / min for the first pass, 1100 m / min for the second pass, and 1300 m / min for the third pass.

[0058] After the above-mentioned cold rolling method, the obtained high-precision CTP printing plate base strip has a thickness of 0.263±0.005mm and a straightness of 30IU. There are defects such as pine branch patterns, sticking, scratches, and small white spots on the surface. The transverse roughness Ra of the strip is 0.30µm. After conventional cleaning, trimming, stretching and straightening, it cannot meet customer requirements.

[0059] The product quality of the above embodiments and comparative examples after cold rolling is shown in Table 1.

[0060] Table 1: From the quality of the CTP printing plate base strips produced by the processing methods of Examples 1 and 2 and Comparative Examples 1 and 2, it can be seen that the present invention can reduce the number of cold rolling passes, significantly improve the cold rolling production efficiency, reduce the cold rolling production cost, and the product quality is excellent and can meet customer needs.

Claims

1. A cold rolling method for a high-precision CTP printing plate substrate, characterized in that The steps of the cold rolling method are as follows: (1) Take a 2.5 mm billet coil, completely recrystallize and anneal it, and then cool it to below 45°C; (2) cold rolling the billet coil processed in step (1) in the following passes: in the first pass, the thickness of 2.5 mm is rolled down to 1.1 mm, in the second pass, the thickness of 1.1 mm is rolled down to 0.50 mm, and in the third pass, the thickness of 0.50 mm is rolled down to (0.25-0.28) mm; (3) In step (2): the interval between two adjacent passes is greater than or equal to 24 hours, the inlet temperature of the aluminum coil of the first pass is ≤45°C, the inlet temperature of the second and third passes is ≤60°C, and the outlet temperature of the aluminum coil of the second and third passes is ≤100°C; (3) In step (2): the surface roughness Ra of the working roll used in the first and second passes is 0.28-0.38 µm, the surface roughness Ra of the working roll used in the third pass is 0.18-0.26 µm, and the surface roughness Ra of the backup rolls in the three passes is 1.0-1.2 µm. (4) During the rolling process in step (2), the concentration ratio of the process lubricant additive is: alcohol 5-8%, ester 2.5-4%; (5) In step (2), the process oil injection pressure of the three passes is adjusted to 5-7 bar, and the process oil injection flow rate of the three passes is adjusted to 40-100%; (6) In step (2), the given tensions of each pass are: the first pass entrance tension is 14±2MPa, and the exit tension is 28±2MPa; the second pass entrance tension is 24±2MPa, and the exit tension is 28±2MPa; the third pass entrance tension is 24±2MPa, and the exit tension is 26±2MPa; (7) In step (2), the rolling speed of each pass is: the rolling speed of the first pass is 400-590 m / min, the rolling speed of the second pass is 800-1100 m / min, and the rolling speed of the third pass is 1000-1400 m / min.

2. The cold rolling method for a high-precision CTP printing plate substrate according to claim 1, characterized in that The process oil injection flow rate in step (5) is: 90% for the first pass, 70% for the second pass, and 55% for the third pass.

3. The cold rolling method for a high-precision CTP printing plate substrate according to claim 1, characterized in that In the step (4), the alcohol in the process lubricant additive is dodecanol and tetradecanol, the ester is hexadecyl ester, and the ratio of dodecanol to tetradecanol is 1:

3.

4. The cold rolling method for a high-precision CTP printing plate substrate according to claim 1, characterized in that The process lubricant additive in step (4) further comprises a surfactant, an antioxidant, an antistatic agent, and a rolling oil compatibility agent, wherein the additive concentration ratio of the surfactant, antioxidant, antistatic agent, and rolling oil compatibility agent is: 0.5-0.7% surfactant, 0.2-0.5% antioxidant, 0.1-0.3% antistatic agent, and 0.8-1.0% rolling oil compatibility agent.

5. The cold rolling method for a high-precision CTP printing plate substrate according to claim 1, characterized in that The surfactant is fatty acid glyceride, the antioxidant is 2,6-di-tert-butyl-p-cresol, the antistatic agent is glyceryl monostearate, and the rolling oil compatibility agent is polyether ester.

6. The cold rolling method for a high-precision CTP printing plate substrate according to claim 1, characterized in that In the step (3), the surfaces of the working rolls of the first pass, the working rolls of the second pass and the working rolls of the third pass are respectively plated with chrome layers, the thickness of the chrome layer of the first pass is 0.2 mm and the hardness is HS97, the thickness of the chrome layer of the second pass is 0.22 mm and the hardness is HS98, and the thickness of the chrome layer of the third pass is 0.25 mm and the hardness is HS99.

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