An antioxidant rubber material for printing blankets and its preparation method

Abstract

This invention relates to the field of printing blankets, specifically to an antioxidant rubber material for printing blankets and its preparation method. It addresses the problem that traditional printing blanket materials are susceptible to oxidation and wear during use, resulting in a significantly shortened service life and performance degradation, thus affecting the quality of printed materials. The preparation method involves adding a highly efficient antioxidant to the rubber material to effectively capture and eliminate free radicals, significantly improving its antioxidant performance. Subsequently, the addition of mercapto-modified boron nitride nanosheets enhances the strength and hardness of the rubber material while maintaining good flexibility, meeting the mechanical performance requirements of printing blankets and improving their abrasion resistance. Furthermore, the mercapto-modified boron nitride nanosheets possess excellent thermal conductivity, enabling the printing blanket to quickly dissipate heat when used in hot environments, further improving its thermal aging and oxidation resistance, and enhancing the durability of the printing blanket.

Description

Technical Field

[0001] This invention relates to the field of printing blankets, and more specifically to an antioxidant rubber material for printing blankets and its preparation method. Background Technology

[0002] As a key component of printing presses, the performance of printing blankets directly affects the quality of printed materials and production efficiency. During the printing process, printing blankets need to withstand significant pressure and friction, and also need to come into contact with various inks, solvents, and other chemicals in a hot environment. As a result, traditional printing blanket materials are prone to oxidation and wear during use, significantly shortening their service life and leading to performance degradation, which in turn affects the quality of printed materials.

[0003] Therefore, developing an antioxidant rubber material for printing blankets and its preparation method is of great significance for improving the service life and printing quality of printing blankets. Summary of the Invention

[0004] In order to overcome the above-mentioned technical problems, the present invention aims to provide an antioxidant rubber material for printing blankets and its preparation method, which solves the problems that traditional printing blanket materials are easily oxidized and worn during use, resulting in a significantly shortened service life and a decline in performance, thus affecting the quality of printed products.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] An antioxidant rubber material for printing blankets, comprising the following components in parts by weight:

[0007] Natural rubber 65-75 parts, EPDM rubber 25-35 parts, styrene-butadiene rubber 18-24 parts, high-efficiency antioxidant 2.5-11.5 parts, mercapto-modified boron nitride nanosheets 12-18 parts, sulfur 1-3 parts, and accelerator TMTD 1-3 parts.

[0008] As a further aspect of the present invention: the highly efficient antioxidant is prepared by the following steps:

[0009] Step A1: Add hexachlorocyclotriphosphazene, anhydrous potassium carbonate, p-phenylenediamine, and anhydrous acetonitrile to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and reflux condenser. Purge with nitrogen for protection and stir the reaction at 20-25℃ and a stirring rate of 300-400 r / min for 15-20 min. Then, raise the temperature to reflux and continue stirring for 15-20 h. After the reaction is complete, cool the reaction product to room temperature, then filter under vacuum. Wash the filter cake 2-3 times with distilled water and then place it in a vacuum drying oven at 60-65℃ for 2-4 h to obtain intermediate 1.

[0010] Step A2: Add 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and chloroform to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and constant pressure dropping funnel, and purge with nitrogen. Stir the reaction at 25-30℃ and 300-400 r / min for 15-20 min. Then, add thionyl chloride dropwise while stirring, controlling the dropping rate to 1-2 drops / s. After the addition is complete, raise the temperature to 50-55℃ and continue stirring for 4-5 h. After the reaction is complete, cool the reaction product to room temperature and then remove the solvent by rotary evaporation to obtain intermediate 2.

[0011] Step A3: Add intermediate 1, intermediate 2, and anhydrous acetonitrile to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and constant pressure dropping funnel. Purge with nitrogen for protection and stir the reaction at 20-25℃ and a stirring rate of 300-400 r / min for 15-20 min. Then, while stirring, add triethylamine solution dropwise until the pH reaches 9-10, controlling the dropping rate to 1-2 drops / s. After the addition is complete, raise the temperature to 60-65℃ and continue stirring for 10-15 h. After the reaction is complete, cool the reaction product to room temperature, then remove the solvent by rotary evaporation. Add the product to dichloromethane and wash it 2-3 times successively with sodium bicarbonate solution, hydrochloric acid solution, and saturated brine. Allow the mixture to stand and separate into layers. Dry the organic phase with anhydrous sodium sulfate, then filter under vacuum. Remove the solvent from the filtrate by rotary evaporation to obtain a high-efficiency antioxidant.

[0012] As a further aspect of the present invention: the ratio of hexachlorocyclotriphosphazene, anhydrous potassium carbonate, p-phenylenediamine and anhydrous acetonitrile in step A1 is 10 mmol: 65-75 mmol: 60 mmol: 80-100 mL.

[0013] As a further aspect of the present invention: the ratio of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, chloroform and sulfoxide in step A2 is 10 mmol: 40-50 mL: 8-12 mL.

[0014] As a further aspect of the present invention: the ratio of intermediate 1, intermediate 2 and anhydrous acetonitrile in step A3 is 10 mmol: 65-75 mmol: 60-80 mL.

[0015] As a further aspect of the present invention: the triethylamine solution in step A3 is a solution with a molar concentration of 0.3-0.5 mol / L formed by dissolving triethylamine in anhydrous acetonitrile.

[0016] As a further aspect of the present invention: the mass fraction of the sodium bicarbonate solution in step A3 is 5-7%, and the mass fraction of the hydrochloric acid solution is 8-10%.

[0017] As a further aspect of the present invention: the thiol-modified boron nitride nanosheets are prepared by the following steps:

[0018] Step B1: Add hexagonal boron nitride and anhydrous glucose to a ball mill jar and ball mill for 12-16 hours at a ball-to-material ratio of 8-10:1 and a ball milling speed of 300-400 r / min. Then add the mixture to deionized water and let it stand for 15-25 minutes. After centrifugation, place the precipitate in a vacuum drying oven and dry it at a temperature of 40-45℃ for 3-5 hours to obtain boron nitride nanosheets.

[0019] Step B2: Add coupling agent KH-590, anhydrous ethanol, and deionized water to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection and stir the reaction at 20-25℃ and a stirring rate of 300-400 r / min for 30-40 min. Then add boron nitride nanosheets and continue stirring the reaction at 75-80℃ for 8-10 h. After the reaction is complete, cool the reaction product to room temperature, centrifuge, and place the precipitate in a vacuum drying oven to dry at 60-65℃ for 6-8 h to obtain mercapto-modified boron nitride nanosheets.

[0020] As a further aspect of the present invention: the ratio of hexagonal boron nitride to anhydrous glucose in step B1 is 1g:8-10g.

[0021] As a further aspect of the present invention: the ratio of the coupling agent KH-590, anhydrous ethanol, deionized water and boron nitride nanosheets in step B2 is 1.5-8.5g: 80-85mL: 10-15mL: 5g.

[0022] As a further aspect of the present invention: a method for preparing an antioxidant rubber material for printing blankets, comprising the following steps:

[0023] Step 1: Weigh out 65-75 parts of natural rubber, 25-35 parts of EPDM rubber, 18-24 parts of styrene-butadiene rubber, 2.5-11.5 parts of high-efficiency antioxidant, 12-18 parts of mercapto-modified boron nitride nanosheets, 1-3 parts of sulfur, and 1-3 parts of accelerator TMTD according to the following weight proportions, and set aside.

[0024] Step 2: Place natural rubber, EPDM rubber and styrene-butadiene rubber into a mixer and mix them at 140-160℃ for 10-20 minutes. Then add a high-efficiency antioxidant, mercapto-modified boron nitride nanosheets, sulfur and accelerator TMTD and continue mixing for 10-20 minutes to obtain the mixed rubber compound.

[0025] Step 3: Put the internally mixed rubber compound into a two-roll mill and pass it through 3-5 times. Then put it into a vulcanizing machine and vulcanize it for 10-20 minutes at a temperature of 160-180℃ to obtain an antioxidant rubber material for printing blankets.

[0026] The beneficial effects of this invention are:

[0027] This invention discloses an antioxidant rubber material for printing blankets and its preparation method. The method involves mixing natural rubber, EPDM rubber, and styrene-butadiene rubber in a Banbury mixer, then adding a high-efficiency antioxidant, mercapto-modified boron nitride nanosheets, sulfur, and an accelerator TMTD, and continuing mixing to obtain a Banbury compound. This compound is then passed through a two-roll mill for thin-pass processing, followed by vulcanization in a vulcanizing machine to obtain the antioxidant rubber material for printing blankets. The addition of a high-efficiency antioxidant to the rubber material effectively captures and eliminates free radicals, preventing oxidation during use. The process involves chemical degradation, significantly improving antioxidant properties. The subsequent addition of mercapto-modified boron nitride nanosheets enhances the strength and hardness of the rubber material while maintaining good flexibility, meeting the mechanical performance requirements of printing blankets. It also improves the abrasion resistance of the printing blankets, extending their service life. Furthermore, the mercapto-modified boron nitride nanosheets possess excellent thermal conductivity, enabling the printing blankets to quickly dissipate heat in hot environments, further improving their thermal aging and oxidation resistance, and enhancing their durability. This aligns with the environmental requirements of the modern printing industry and has broad market application prospects.

[0028] In the preparation of antioxidant rubber materials for printing blankets, a highly efficient antioxidant was first prepared. Firstly, hexachlorocyclotriphosphazene and p-phenylenediamine reacted, with the chlorine atom on hexachlorocyclotriphosphazene reacting with an amino group on p-phenylenediamine to obtain intermediate 1. Then, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and sulfoxide were reacted, with sulfoxide converting the carboxyl group on 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid into an acyl chloride group to obtain intermediate 2. Finally, intermediates 1 and 2 reacted, with the amino group on intermediate 1 reacting with the acyl chloride group on intermediate 2, introducing a large number of hindered phenolic structures to obtain the highly efficient antioxidant. The molecular structure of this highly efficient antioxidant contains a large number of hindered phenolic structures, which can effectively capture and scavenge free radicals. The synergistic effect of these hindered phenolic structures endows it with excellent antioxidant properties. Therefore, adding it to rubber materials can significantly improve the antioxidant properties of the rubber materials and extend the service life of printing blankets.

[0029] In the process of preparing antioxidant rubber materials for printing blankets, a mercapto-modified boron nitride nanosheet was also prepared. First, glucose was used as a ball milling aid. The impact between the grinding balls and the material during ball milling, along with the temperature rise caused by the impact friction, enabled the exfoliation modification of the hexagonal boron nitride layers. Glucose was then grafted to introduce a large number of hydroxyl groups, resulting in boron nitride nanosheets. Subsequently, the boron nitride nanosheets were modified using a coupling agent KH-590. The siloxanes on the coupling agent KH-590 hydrolyze to form silanols, which can undergo dehydration condensation with the hydroxyl groups on the boron nitride nanosheets. By introducing organosilicon and a large number of thiol groups, thiol-modified boron nitride nanosheets are obtained. These boron nitride nanosheets exhibit excellent mechanical and thermal conductivity. The modified nanosheets also possess excellent dispersibility, allowing them to be uniformly distributed within rubber materials. Furthermore, they can participate in the cross-linking reaction of rubber through thiol-alkene click reactions, increasing interfacial interactions and forming a boron nitride nanosheet particle network. This results in a consistent improvement in the thermal and mechanical properties of the rubber material, significantly enhancing both and further extending the service life of printing blankets. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1:

[0032] This embodiment describes a method for preparing an antioxidant rubber material for printing blankets, comprising the following steps:

[0033] Step S1: 10 mmol hexachlorocyclotriphosphazene, 65 mmol anhydrous potassium carbonate, 60 mmol p-phenylenediamine and 80 mL anhydrous acetonitrile were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection. The mixture was stirred at 20 °C and 300 r / min for 15 min. Then the temperature was raised to reflux and the mixture was stirred for 15 h. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filter cake was washed twice with distilled water and then placed in a vacuum drying oven and dried at 60 °C for 2 h to obtain intermediate 1.

[0034] Step S2: 10 mmol of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and 40 mL of chloroform were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and constant pressure dropping funnel. Nitrogen gas was introduced for protection. The mixture was stirred for 15 min at 25 °C and a stirring rate of 300 r / min. Then, 8 mL of thionyl chloride was added dropwise while stirring, with the dropping rate controlled at 1 drop / s. After the addition was completed, the temperature was raised to 50 °C and the mixture was stirred for another 4 h. After the reaction was completed, the reaction product was cooled to room temperature and then the solvent was removed by rotary evaporation to obtain intermediate 2.

[0035] Step S3: 10 mmol of intermediate 1, 65 mmol of intermediate 2 and 60 mL of anhydrous acetonitrile were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and constant pressure dropping funnel. Nitrogen gas was introduced for protection. The mixture was stirred for 15 min at 20 °C and a stirring rate of 300 r / min. Then, a 0.3 mol / L triethylamine solution was added dropwise while stirring until the pH reached 9. The dropping rate was controlled at 1 drop / s. After the addition was completed, the temperature was raised to 60 °C and the reaction was stirred for 10 h. After the reaction was completed, the reaction product was cooled to room temperature and the solvent was removed by rotary evaporation. The product was then added to dichloromethane and washed twice with 5% sodium bicarbonate solution, 8% hydrochloric acid solution and saturated brine solution. The mixture was then allowed to stand and separate into layers. The organic phase was dried with anhydrous sodium sulfate and then vacuum filtered. The filtrate was then evaporated by rotary evaporation to remove the solvent, yielding a high-efficiency antioxidant.

[0036] Step S4: Add 1g of hexagonal boron nitride and 8g of anhydrous glucose to a ball mill jar, and ball mill for 12h at a ball-to-material ratio of 8:1 and a ball milling speed of 300r / min. Then add it to deionized water and let it stand for 15min. After centrifugation, place the precipitate in a vacuum drying oven and dry it at 40℃ for 3h to obtain boron nitride nanosheets.

[0037] Step S5: Add 1.5g of coupling agent KH-590, 80mL of anhydrous ethanol and 10mL of deionized water to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Purge with nitrogen for protection and stir at 20℃ and 300r / min for 30min. Then add 5g of boron nitride nanosheets and continue stirring at 75℃ for 8h. After the reaction is complete, cool the reaction product to room temperature, centrifuge, and place the precipitate in a vacuum drying oven and dry at 60℃ for 6h to obtain mercapto-modified boron nitride nanosheets.

[0038] Step S6: Weigh out 65 parts of natural rubber, 25 parts of EPDM rubber, 18 parts of styrene-butadiene rubber, 2.5 parts of high-efficiency antioxidant, 12 parts of mercapto-modified boron nitride nanosheets, 1 part of sulfur, and 1 part of accelerator TMTD according to the following weight proportions, and set aside.

[0039] Step S7: Place natural rubber, EPDM rubber and styrene-butadiene rubber into a mixer and mix at 140°C for 10 minutes. Then add high-efficiency antioxidant, mercapto-modified boron nitride nanosheets, sulfur and accelerator TMTD and continue mixing for 10 minutes to obtain the mixed rubber compound.

[0040] Step S8: The internally mixed rubber compound is passed through a two-roll mill three times, and then placed in a vulcanizing machine and vulcanized at 160°C for 10 minutes to obtain an antioxidant rubber material for printing blankets.

[0041] Example 2:

[0042] This embodiment describes a method for preparing an antioxidant rubber material for printing blankets, comprising the following steps:

[0043] Step S1: 10 mmol hexachlorocyclotriphosphazene, 70 mmol anhydrous potassium carbonate, 60 mmol p-phenylenediamine and 90 mL anhydrous acetonitrile were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection. The mixture was stirred at 22 °C and 350 r / min for 18 min. Then the temperature was raised to reflux and the mixture was stirred for another 18 h. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filter cake was washed twice with distilled water and then placed in a vacuum drying oven and dried at 62 °C for 3 h to obtain intermediate 1.

[0044] Step S2: 10 mmol of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and 45 mL of chloroform were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and constant pressure dropping funnel. Nitrogen gas was introduced for protection, and the reaction was stirred at 28 °C and a stirring rate of 350 r / min for 18 min. Then, 10 mL of thionyl chloride was added dropwise while stirring, with the dropping rate controlled at 1 drop / s. After the addition was completed, the temperature was raised to 52 °C and the reaction was stirred for another 4.5 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation to obtain intermediate 2.

[0045] Step S3: 10 mmol of intermediate 1, 70 mmol of intermediate 2, and 70 mL of anhydrous acetonitrile were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and constant pressure dropping funnel. Nitrogen gas was introduced for protection, and the mixture was stirred for 18 min at 22 °C and a stirring rate of 350 r / min. Then, while stirring, a 0.4 mol / L triethylamine solution was added dropwise to anhydrous acetonitrile until the pH reached 9.5, with the dropping rate controlled at 1 drop / s. After the addition was completed, the temperature was raised to 62 °C and the reaction was stirred for 12 h. After the reaction was completed, the reaction product was cooled to room temperature, and the solvent was removed by rotary evaporation. The product was then added to dichloromethane and washed twice with 6% sodium bicarbonate solution, 9% hydrochloric acid solution, and saturated brine. The mixture was then allowed to stand and separate into layers. The organic phase was dried with anhydrous sodium sulfate and then filtered under vacuum. The filtrate was then evaporated by rotary evaporation to remove the solvent, yielding a high-efficiency antioxidant.

[0046] Step S4: Add 1g of hexagonal boron nitride and 9g of anhydrous glucose to a ball mill jar, and ball mill for 14h at a ball-to-material ratio of 9:1 and a ball milling speed of 350r / min. Then add it to deionized water and let it stand for 20min. After centrifugation, place the precipitate in a vacuum drying oven and dry it at a temperature of 42℃ for 4h to obtain boron nitride nanosheets.

[0047] Step S5: Add 5g of coupling agent KH-590, 82mL of anhydrous ethanol and 12mL of deionized water to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Purge with nitrogen for protection and stir at 22℃ and 350r / min for 35min. Then add 5g of boron nitride nanosheets and continue stirring at 78℃ for 9h. After the reaction is complete, cool the reaction product to room temperature, centrifuge, and place the precipitate in a vacuum drying oven and dry at 62℃ for 7h to obtain mercapto-modified boron nitride nanosheets.

[0048] Step S6: Weigh out 70 parts of natural rubber, 30 parts of EPDM rubber, 21 parts of styrene-butadiene rubber, 7 parts of high-efficiency antioxidant, 15 parts of mercapto-modified boron nitride nanosheets, 2 parts of sulfur, and 2 parts of accelerator TMTD according to the following weight proportions, and set aside.

[0049] Step S7: Place natural rubber, EPDM rubber and styrene-butadiene rubber into a mixer and mix at 150°C for 15 minutes. Then add high-efficiency antioxidant, mercapto-modified boron nitride nanosheets, sulfur and accelerator TMTD and continue mixing for 15 minutes to obtain the mixed rubber compound.

[0050] Step S8: The internally mixed rubber compound is passed through a two-roll mill four times, and then placed in a vulcanizing machine and vulcanized at 170°C for 15 minutes to obtain an antioxidant rubber material for printing blankets.

[0051] Example 3:

[0052] This embodiment describes a method for preparing an antioxidant rubber material for printing blankets, comprising the following steps:

[0053] Step S1: 10 mmol hexachlorocyclotriphosphazene, 75 mmol anhydrous potassium carbonate, 60 mmol p-phenylenediamine and 100 mL anhydrous acetonitrile were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection. The mixture was stirred at 25 °C and 400 r / min for 20 min. Then the temperature was raised to reflux and the mixture was stirred for another 20 h. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filter cake was washed three times with distilled water and then placed in a vacuum drying oven and dried at 65 °C for 4 h to obtain intermediate 1.

[0054] Step S2: 10 mmol of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and 50 mL of chloroform were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and constant pressure dropping funnel. Nitrogen gas was introduced for protection, and the reaction was stirred at 30 °C and 400 r / min for 20 min. Then, 12 mL of thionyl chloride was added dropwise while stirring, with the dropping rate controlled at 2 drops / s. After the addition was completed, the temperature was raised to 55 °C and the reaction was stirred for 5 h. After the reaction was completed, the reaction product was cooled to room temperature and then the solvent was removed by rotary evaporation to obtain intermediate 2.

[0055] Step S3: 10 mmol of intermediate 1, 75 mmol of intermediate 2, and 80 mL of anhydrous acetonitrile were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and constant pressure dropping funnel. Nitrogen gas was introduced for protection, and the mixture was stirred at 25 °C and a stirring rate of 400 r / min for 20 min. Then, while stirring, a 0.5 mol / L triethylamine solution was added dropwise to anhydrous acetonitrile until the pH reached 10, with a dropping rate of 2 drops / s. After the addition was complete, the temperature was raised to 65 °C and the reaction was continued for 15 h. After the reaction was completed, the reaction product was cooled to room temperature, and the solvent was removed by rotary evaporation. The product was then added to dichloromethane and washed three times in sequence with a 7% sodium bicarbonate solution, a 10% hydrochloric acid solution, and saturated brine. The mixture was then allowed to stand and separate into layers. The organic phase was dried with anhydrous sodium sulfate and then vacuum filtered. The filtrate was then evaporated by rotary evaporation to remove the solvent, yielding a high-efficiency antioxidant.

[0056] Step S4: Add 1g of hexagonal boron nitride and 10g of anhydrous glucose to a ball mill jar, and ball mill for 16h at a ball-to-material ratio of 10:1 and a ball milling speed of 400r / min. Then add it to deionized water and let it stand for 25min. After centrifugation, place the precipitate in a vacuum drying oven and dry it at a temperature of 45℃ for 5h to obtain boron nitride nanosheets.

[0057] Step S5: Add 8.5g of coupling agent KH-590, 85mL of anhydrous ethanol and 15mL of deionized water to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Purge with nitrogen for protection and stir at 25℃ and 400r / min for 40min. Then add 5g of boron nitride nanosheets and continue stirring at 80℃ for 10h. After the reaction is complete, cool the reaction product to room temperature, centrifuge, and place the precipitate in a vacuum drying oven and dry at 65℃ for 8h to obtain mercapto-modified boron nitride nanosheets.

[0058] Step S6: Weigh out 75 parts of natural rubber, 35 parts of EPDM rubber, 24 parts of styrene-butadiene rubber, 11.5 parts of high-efficiency antioxidant, 18 parts of mercapto-modified boron nitride nanosheets, 3 parts of sulfur, and 3 parts of accelerator TMTD according to the following weight proportions, and set aside.

[0059] Step S7: Place natural rubber, EPDM rubber and styrene-butadiene rubber into a mixer and mix at 160°C for 20 minutes. Then add high-efficiency antioxidant, mercapto-modified boron nitride nanosheets, sulfur and accelerator TMTD and continue mixing for 20 minutes to obtain the mixed rubber compound.

[0060] Step S8: The internally mixed rubber compound is passed through a two-roll mill 5 times, and then placed in a vulcanizing machine and vulcanized at 180°C for 20 minutes to obtain an antioxidant rubber material for printing blankets.

[0061] Comparative Example 1:

[0062] This comparative example illustrates a method for preparing an antioxidant rubber material for printing blankets, comprising the following steps:

[0063] Step S1: Weigh out 75 parts of natural rubber, 35 parts of EPDM rubber, 24 parts of styrene-butadiene rubber, 3 parts of sulfur, and 3 parts of accelerator TMTD according to the weight ratio, and set aside.

[0064] Step S2: Place natural rubber, EPDM rubber and styrene-butadiene rubber into a mixer and mix at 160°C for 20 minutes. Then add sulfur and accelerator TMTD and continue mixing for 20 minutes to obtain the mixed rubber compound.

[0065] Step S3: The internally mixed rubber compound is passed through a two-roll mill 5 times, and then placed in a vulcanizing machine and vulcanized at 180°C for 20 minutes to obtain an antioxidant rubber material for printing blankets.

[0066] Comparative Example 2:

[0067] This comparative example illustrates a method for preparing an antioxidant rubber material for printing blankets, comprising the following steps:

[0068] Step S1: Weigh out 75 parts of natural rubber, 35 parts of EPDM rubber, 24 parts of styrene-butadiene rubber, 11.5 parts of antioxidant BHT, 3 parts of sulfur, and 3 parts of accelerator TMTD according to the weight ratio, and set aside.

[0069] Step S2: Place natural rubber, EPDM rubber and styrene-butadiene rubber into a mixer and mix at 160°C for 20 minutes. Then add antioxidant BHT, sulfur and accelerator TMTD and continue mixing for 20 minutes to obtain the mixed rubber compound.

[0070] Step S3: The internally mixed rubber compound is passed through a two-roll mill 5 times, and then placed in a vulcanizing machine and vulcanized at 180°C for 20 minutes to obtain an antioxidant rubber material for printing blankets.

[0071] Comparative Example 3:

[0072] This comparative example illustrates a method for preparing an antioxidant rubber material for printing blankets, comprising the following steps:

[0073] Step S1: 10 mmol hexachlorocyclotriphosphazene, 75 mmol anhydrous potassium carbonate, 60 mmol p-phenylenediamine and 100 mL anhydrous acetonitrile were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection. The mixture was stirred at 25 °C and 400 r / min for 20 min. Then the temperature was raised to reflux and the mixture was stirred for another 20 h. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filter cake was washed three times with distilled water and then placed in a vacuum drying oven and dried at 65 °C for 4 h to obtain intermediate 1.

[0074] Step S2: 10 mmol of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and 50 mL of chloroform were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and constant pressure dropping funnel. Nitrogen gas was introduced for protection, and the reaction was stirred at 30 °C and 400 r / min for 20 min. Then, 12 mL of thionyl chloride was added dropwise while stirring, with the dropping rate controlled at 2 drops / s. After the addition was completed, the temperature was raised to 55 °C and the reaction was stirred for 5 h. After the reaction was completed, the reaction product was cooled to room temperature and then the solvent was removed by rotary evaporation to obtain intermediate 2.

[0075] Step S3: 10 mmol of intermediate 1, 75 mmol of intermediate 2, and 80 mL of anhydrous acetonitrile were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and constant pressure dropping funnel. Nitrogen gas was introduced for protection, and the mixture was stirred at 25 °C and a stirring rate of 400 r / min for 20 min. Then, while stirring, a 0.5 mol / L triethylamine solution was added dropwise to anhydrous acetonitrile until the pH reached 10, with a dropping rate of 2 drops / s. After the addition was complete, the temperature was raised to 65 °C and the reaction was continued for 15 h. After the reaction was completed, the reaction product was cooled to room temperature, and the solvent was removed by rotary evaporation. The product was then added to dichloromethane and washed three times in sequence with a 7% sodium bicarbonate solution, a 10% hydrochloric acid solution, and saturated brine. The mixture was then allowed to stand and separate into layers. The organic phase was dried with anhydrous sodium sulfate and then vacuum filtered. The filtrate was then evaporated by rotary evaporation to remove the solvent, yielding a high-efficiency antioxidant.

[0076] Step S4: Weigh out 75 parts of natural rubber, 35 parts of EPDM rubber, 24 parts of styrene-butadiene rubber, 11.5 parts of high-efficiency antioxidant, 3 parts of sulfur, and 3 parts of accelerator TMTD according to the following weight proportions, and set aside.

[0077] Step S5: Place natural rubber, EPDM rubber and styrene-butadiene rubber into a mixer and mix at 160°C for 20 minutes. Then add high-efficiency antioxidant, sulfur and accelerator TMTD and continue mixing for 20 minutes to obtain the mixed rubber compound.

[0078] Step S6: The internally mixed rubber compound is passed through a two-roll mill 5 times, and then placed in a vulcanizing machine and vulcanized at 180°C for 20 minutes to obtain an antioxidant rubber material for printing blankets.

[0079] Comparative Example 4:

[0080] This comparative example illustrates a method for preparing an antioxidant rubber material for printing blankets, comprising the following steps:

[0081] Step S1: Add 1g of hexagonal boron nitride and 10g of anhydrous glucose to a ball mill jar, and ball mill for 16h at a ball-to-material ratio of 10:1 and a ball milling speed of 400r / min. Then add it to deionized water and let it stand for 25min. After centrifugation, place the precipitate in a vacuum drying oven and dry it at a temperature of 45℃ for 5h to obtain boron nitride nanosheets.

[0082] Step S2: Add 8.5g of coupling agent KH-590, 85mL of anhydrous ethanol and 15mL of deionized water to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Purge with nitrogen for protection and stir at 25℃ and 400r / min for 40min. Then add 5g of boron nitride nanosheets and continue stirring at 80℃ for 10h. After the reaction is complete, cool the reaction product to room temperature, centrifuge, and place the precipitate in a vacuum drying oven and dry at 65℃ for 8h to obtain mercapto-modified boron nitride nanosheets.

[0083] Step S3: Weigh out 75 parts of natural rubber, 35 parts of EPDM rubber, 24 parts of styrene-butadiene rubber, 18 parts of mercapto-modified boron nitride nanosheets, 3 parts of sulfur, and 3 parts of accelerator TMTD according to the following weight proportions, and set aside.

[0084] Step S4: Place natural rubber, EPDM rubber and styrene-butadiene rubber into a mixer and mix at 160°C for 20 minutes. Then add mercapto-modified boron nitride nanosheets, sulfur and accelerator TMTD and continue mixing for 20 minutes to obtain the mixed rubber compound.

[0085] Step S5: The internally mixed rubber compound is passed through a two-roll mill 5 times, and then placed in a vulcanizing machine and vulcanized at 180°C for 20 minutes to obtain an antioxidant rubber material for printing blankets.

[0086] The properties of the antioxidant rubber materials used for printing blankets in Examples 1-3 and Comparative Examples 1-4 were tested, and the test results are shown in the table below:

[0087]

[0088] Referring to the data in the table above, it can be seen that adding a high-efficiency antioxidant can effectively improve the antioxidant properties of rubber materials, and adding mercapto-modified boron nitride nanosheets can effectively improve the mechanical properties of rubber materials. Under the synergistic effect of the high-efficiency antioxidant and mercapto-modified boron nitride nanosheets, the resulting rubber materials have excellent antioxidant and mechanical properties.

[0089] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," 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 invention. In this specification, 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.

[0090] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. An antioxidant rubber material for printing blankets, characterized in that, Includes the following components by weight: Natural rubber 65-75 parts, EPDM rubber 25-35 parts, styrene-butadiene rubber 18-24 parts, high-efficiency antioxidant 2.5-11.5 parts, mercapto-modified boron nitride nanosheets 12-18 parts, sulfur 1-3 parts, and accelerator TMTD 1-3 parts; The highly effective antioxidant is prepared by the following steps: Step A1: Hexachlorocyclotriphosphazene, anhydrous potassium carbonate, p-phenylenediamine and anhydrous acetonitrile were stirred and reacted. After the reaction was completed, the reaction product was cooled and then vacuum filtered. The filter cake was washed and dried to obtain intermediate 1. Step A2: 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and chloroform were stirred and reacted. Then, thionyl chloride was added dropwise while stirring. After the addition was complete, the reaction was continued to be stirred. After the reaction was completed, the reaction product was cooled and then evaporated by rotary evaporation to obtain intermediate 2. Step A3: Intermediate 1, Intermediate 2 and anhydrous acetonitrile are stirred and reacted. Then, triethylamine solution is added dropwise while stirring. After the addition is complete, the reaction is continued to be stirred. After the reaction is completed, the reaction product is cooled and then evaporated by rotary evaporation. The product is then added to dichloromethane and washed successively with sodium bicarbonate solution, hydrochloric acid solution and saturated brine. After standing and separating the layers, the organic phase is dried and then filtered under vacuum. The filtrate is evaporated by rotary evaporation to obtain a high-efficiency antioxidant. The thiol-modified boron nitride nanosheets were prepared by the following steps: Step B1: Add hexagonal boron nitride and anhydrous glucose to a ball mill jar for ball milling, then add to deionized water and let stand, then centrifuge, dry the precipitate to obtain boron nitride nanosheets; Step B2: The coupling agent KH-590, anhydrous ethanol and deionized water were stirred and reacted. Then boron nitride nanosheets were added and the reaction was stirred and continued. After the reaction was completed, the reaction product was cooled, centrifuged, and the precipitate was dried to obtain mercapto-modified boron nitride nanosheets.

2. The antioxidant rubber material for printing blankets according to claim 1, characterized in that, The ratio of hexachlorocyclotriphosphazene, anhydrous potassium carbonate, p-phenylenediamine, and anhydrous acetonitrile in step A1 is 10 mmol: 65-75 mmol: 60 mmol: 80-100 mL.

3. The antioxidant rubber material for printing blankets according to claim 1, characterized in that, The ratio of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, chloroform, and sulfoxide in step A2 is 10 mmol: 40-50 mL: 8-12 mL.

4. The antioxidant rubber material for printing blankets according to claim 1, characterized in that, The ratio of intermediate 1, intermediate 2 and anhydrous acetonitrile in step A3 is 10 mmol: 65-75 mmol: 60-80 mL.

5. The antioxidant rubber material for printing blankets according to claim 1, characterized in that, The triethylamine solution mentioned in step A3 is a solution with a molar concentration of 0.3-0.5 mol / L formed by dissolving triethylamine in anhydrous acetonitrile.

6. The antioxidant rubber material for printing blankets according to claim 1, characterized in that, The sodium bicarbonate solution in step A3 has a mass fraction of 5-7%, and the hydrochloric acid solution has a mass fraction of 8-10%.

7. The antioxidant rubber material for printing blankets according to claim 1, characterized in that, The ratio of hexagonal boron nitride to anhydrous glucose in step B1 is 1g:8-10g.

8. The antioxidant rubber material for printing blankets according to claim 1, characterized in that, The ratio of coupling agent KH-590, anhydrous ethanol, deionized water and boron nitride nanosheets in step B2 is 1.5-8.5g: 80-85mL: 10-15mL: 5g.

9. A method for preparing an antioxidant rubber material for printing blankets according to any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Weigh out 65-75 parts of natural rubber, 25-35 parts of EPDM rubber, 18-24 parts of styrene-butadiene rubber, 2.5-11.5 parts of high-efficiency antioxidant, 12-18 parts of mercapto-modified boron nitride nanosheets, 1-3 parts of sulfur, and 1-3 parts of accelerator TMTD according to the following weight proportions, and set aside. Step 2: Place natural rubber, EPDM rubber and styrene-butadiene rubber into a mixer and mix them at 140-160℃ for 10-20 minutes. Then add a high-efficiency antioxidant, mercapto-modified boron nitride nanosheets, sulfur and accelerator TMTD and continue mixing for 10-20 minutes to obtain the mixed rubber compound. Step 3: Put the internally mixed rubber compound into a two-roll mill and pass it through 3-5 times. Then put it into a vulcanizing machine and vulcanize it for 10-20 minutes at a temperature of 160-180℃ to obtain an antioxidant rubber material for printing blankets.

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