NBR compound for low hardness ink resistant printer roller
By using emulsion polymerization and hydrazone crosslinking of aminosilane-modified silica and α-bromoisobutyryl bromide initiator to graft silica, the problems of low hardness and insufficient mechanical properties of NBR rollers were solved, achieving high oil resistance and excellent printer roller performance, and reducing production costs.
Patent Information
- Application Number
- CN202611185126.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-06
- Publication Date
- 2026-11-06
AI Technical Summary
Existing NBR rollers have high hardness, which can easily damage the print head and paper. They also lack mechanical properties, making it difficult to balance low hardness and high oil resistance. Traditional modification methods result in insufficient wear resistance and service life.
Aminosilane-modified silica and α-bromoisobutyryl bromide initiator were grafted onto silica, and NBR compound was formed through emulsion polymerization and hydrazone crosslinking, combined with a dynamic covalent network, achieving low hardness, high oil resistance and excellent mechanical properties.
After immersion in ink for 72 hours, the volume expansion rate is controlled within 4%, tensile strength is improved, compression set is reduced, wear resistance is enhanced, printing accuracy and lifespan are extended, and the cost is only 1/3 of that of HNBR.
Abstract
Description
Technical Field
[0001] This invention belongs to the field of rubber material technology, specifically relating to a low-hardness, ink-resistant NBR rubber compound for ink printer rollers. Background Technology
[0002] As a core component of printing equipment, the performance of printer rollers directly affects print quality and equipment lifespan. While traditional nitrile rubber (NBR) rollers possess good oil resistance, they still face numerous technical challenges in practical applications. Currently, commercially available NBR rollers generally have high hardness (Shore A above 60°), which can easily damage the print head and paper during high-speed printing. To reduce hardness, large amounts of plasticizers are typically added, but this significantly reduces oil resistance, causing the rollers to swell and deform after prolonged contact with ink, severely impacting print accuracy. Tests show that low-hardness NBR compounds modified with plasticizers can experience a volume expansion rate of 8-12% after 72 hours of ink immersion, completely failing to meet the requirements of high-precision printing.
[0003] Furthermore, existing low-hardness NBR compounds generally suffer from insufficient mechanical properties. To reduce costs, manufacturers often add large amounts of cheap fillers such as calcium carbonate, resulting in insufficient tensile strength (typically below 5 MPa), poor abrasion resistance, and a significantly shortened service life under high-speed printing conditions. Regarding the vulcanization system, traditional sulfur vulcanization processes struggle to form an effective cross-linking network in low-hardness compounds, making the rollers prone to compression set and gradual deterioration of resilience during use. While some improvements employ peroxide vulcanization or NBR / PVC blending technologies, these methods either increase the brittleness of the compound or affect long-term performance due to PVC plasticizer migration. More advanced hydrogenated nitrile butadiene rubber (HNBR) can improve oil resistance, but its high cost (3-5 times that of ordinary NBR) severely restricts its widespread application in printer rollers. These technological bottlenecks make the development of NBR compounds that combine low hardness, high oil resistance, and excellent mechanical properties a critical technical challenge that the industry urgently needs to overcome. Summary of the Invention
[0004] To address the challenge of balancing low hardness and strong mechanical properties in existing NBR compounds, this invention provides an NBR compound with low hardness, high ink resistance, and resistance to permanent compression set, along with its preparation method. The technical solution is as follows:
[0005] A method for preparing a low-hardness, ink-resistant NBR rubber compound for printer rollers includes the following steps: amino-modifying silica with aminosilane to obtain amino-containing silica; fully dissolving the amino-containing silica and reacting it dropwise with α-bromoisobutyryl bromide at low temperature to obtain initiator-grafted silica; emulsion polymerizing the initiator-grafted silica with butadiene and acrylonitrile monomers to obtain NBR-grafted modified silica; mixing nitrile rubber, aldehyde-terminated liquid nitrile rubber, and adipyl hydrazine to crosslink and generate hydrazone bonds; adding 2-halocyclopropane carboxylic acid for grafting; uniformly mixing the modified silica with inorganic pigments and then adding it to the system, mixing thoroughly; adding plasticizer, antioxidant, compounding agent, vulcanizing agent, and accelerator, mixing thoroughly, and then discharging the binder to obtain the final product.
[0006] Furthermore, the aminosilane accounts for 0.2-0.5% of the mass of the silica; the α-bromoisobutyryl bromide accounts for 0.2-0.6% of the silica; and the sum of the masses of butadiene and acrylonitrile monomers to the mass ratio of the initiator-grafted silica is 50-70:1.
[0007] Furthermore, the 2-halocyclopropane carboxylic acid includes one or more of 2-chlorocyclopropane carboxylic acid, 2-bromocyclopropane carboxylic acid, or 2-fluorocyclopropane carboxylic acid.
[0008] Furthermore, the plasticizer includes one or more of dibutyl diglyceride, trioctyl trimellitate, dioctyl terephthalate, dioctyl sebacate, or dioctyl adipate; the antioxidant includes one or more of octyl diphenylamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, 2-mercaptobenzimidazole, or stylated phenol; the accelerator includes one or more of N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, dibenzothiazole disulfide, tetramethylthiuram disulfide, tetramethylthiuram monosulfide, zinc diethyldithiocarbamate, or 1,3-diphenylguanidine.
[0009] Further, nitrile rubber is added to a mixer, followed by aldehyde-terminated liquid nitrile rubber and adipic hydrazide. The mixer temperature is controlled at 50-70°C, and the mixture is stirred for 3-10 minutes. Then, the temperature is raised to 110-130°C, and the mixture is stirred for another 3-10 minutes. 2-Halocyclopropanecarboxylic acid and dicumyl peroxide are added, and the temperature is raised to 130-150°C. The mixture is stirred for 8-12 minutes, and cyclopropane groups are grafted onto the NBR molecular chain through mechanical force and an initiator. Modified silica is added and dispersed evenly. The temperature is lowered to below 100°C, and antioxidants and compounding agents are added. Finally, sulfur and accelerators are added, and the mixture is stirred evenly and discharged.
[0010] Furthermore, the mass ratio of dicumyl peroxide to 2-halocyclopropanecarboxylic acid is 1:0.05~0.15.
[0011] Furthermore, amino-containing silica is fully dispersed to prepare a solution of 3-8 g / L, and triethylamine is added at 0.1-0.15% of the mass of amino-containing silica. α-bromoisobutyryl bromide is added dropwise at 0-5℃, and the reaction is maintained at this temperature for 20-30 h to obtain initiator-grafted silica.
[0012] Further, an aqueous solution of sodium dodecyl sulfate was prepared; the initiator-grafted silica was dispersed in toluene, and the sodium dodecyl sulfate aqueous solution was added to emulsify it; butadiene and acrylonitrile monomers were added, followed by copper salt, tertiary amine catalyst, and ascorbic acid, and the reaction was carried out at 50-70℃ for 20-30 h; after demulsification, the product was collected and dried to obtain NBR-grafted modified silica.
[0013] Further, liquid nitrile rubber is dissolved in toluene, and sodium periodate (0.3-0.8% by mass of the liquid nitrile rubber) is added and stirred for 1-3 hours. Water is added to dissolve and remove unreacted oxidant, the organic phase is separated, and the solvent is removed by vacuum distillation to obtain aldehyde-terminated liquid nitrile rubber.
[0014] A low-hardness, ink-resistant NBR rubber compound for printer rollers prepared by the above method comprises, by weight, the following components: 80-120 parts nitrile rubber, 20-30 parts liquid nitrile rubber, 10-20 parts modified silica, 30-50 parts inorganic pigment, 15-25 parts plasticizer, 1-4 parts antioxidant, 1-2 parts 2-halocyclopropanecarboxylic acid, 0.6-0.9 parts adipamide, 0.5-2 parts vulcanizing agent, 1.5-4 parts accelerator, and 3.5-7 parts activator.
[0015] By adopting the above scheme, the method of the present invention has the following advantages:
[0016] 1. The hydrazone-bonded dynamic covalent plasticizing network constructed in this invention covalently binds the liquid nitrile rubber plasticizing component to the matrix crosslinking network. While achieving an ultra-low Shore A hardness of 20-30, it completely avoids the inherent defects of small molecule plasticizers, such as easy migration and extraction by ink solvents. The volume expansion rate of the rubber compound after 72 hours of ink immersion can be controlled to within 4%, which is far lower than the expansion level of up to 8% of traditional plasticized modified rubber compounds. This fundamentally breaks through the performance bottleneck of the difficulty in balancing low hardness and ink resistance. At the same time, the ultra-low hardness can effectively avoid damage to the print head and paper by the rubber roller during high-speed printing, and improve print adhesion.
[0017] 2. The single-molecule NBR grafted silica functional filler used in this invention achieves molecular-level compatibility between the filler and the matrix by growing NBR molecular chains homogeneous with the matrix in situ on the filler surface. While providing a reinforcing effect, it does not cause a significant increase in the hardness of the rubber compound like conventional silica or calcium carbonate fillers. It can improve the tensile strength of the rubber compound while maintaining ultra-low hardness. At the same time, the nanoscale physical barrier layer formed by the grafted filler can further hinder the penetration and diffusion of ink solvents, thereby improving the wear resistance of the rubber compound and effectively extending the service life of the rubber roller.
[0018] 3. The NBR compound of this invention utilizes a dual crosslinking network system of dynamic hydrazone bonds and sulfur covalent bonds. The dynamic hydrazone bonds provide low-modulus flexibility, ensuring the low hardness of the rubber roller, while the sulfur covalent bonds provide a stable crosslinking skeleton. At the same time, the trace copper ions remaining during the polymerization process can further promote the dynamic exchange of disulfide bonds in the vulcanization network. This allows the crosslinking network to achieve rapid elastic recovery through the reversible exchange of dynamic bonds after the compound is subjected to compressive load. The compression set can be controlled at around 10%, which is far superior to the compression set of traditional low-hardness NBR compounds of more than 20%, ensuring the resilience and printing accuracy stability of the rubber roller after long-term use.
[0019] 4. The donor-acceptor cyclopropane mechanochemical activation mechanism introduced in the rubber compound of this invention can achieve in-situ functionalization using only the shear force during the mixing process, without the need for additional catalysts. The instantaneously generated polar intermediates can further enhance the interaction between molecular chains and assist in filler dispersion. At the same time, this solution completely avoids the plasticizer migration problem of NBR / PVC blend system, the brittleness problem of peroxide vulcanization system, and the high cost bottleneck of HNBR. The raw material cost of the entire solution is only about 1 / 3 of that of HNBR, and all processing steps are compatible with conventional rubber production equipment, without the need for customized equipment. It has extremely strong industrial scale-up potential and can achieve performance upgrades of printer rollers without significantly increasing production costs. Detailed Implementation
[0020] Example 1: (1) Silica was dispersed in ethanol, and KH550 was added at 0.25% of the mass of Silica. The mixture was reacted at 80°C for 2 hours to obtain Silica with amino groups on the surface. The Silica with amino groups was ultrasonically dispersed in anhydrous DMF to prepare a uniform solution of 5 mg / ml. Triethylamine at 0.12% of the mass of the Silica with amino groups was added, and α-bromoisobutyryl bromide at 0°C was added dropwise. The mixture was kept warm for 24 hours to obtain ATRP initiator-grafted Silica.
[0021] (2) Sodium dodecyl sulfate was placed in water to prepare an aqueous solution of sodium dodecyl sulfate; ATRP initiator-grafted silica was dispersed in toluene, and butadiene and acrylonitrile monomers were added to make the mass ratio of monomer to initiator-grafted silica 60:1; then it was slowly added dropwise to the aqueous solution of sodium dodecyl sulfate and emulsified by high-speed stirring to obtain an emulsion; 10ppm CuCl2, 10ppm PMDETA and 0.1 part ascorbic acid were added to the emulsion, mixed evenly, and reacted at 60℃ for 24h; the emulsion was broken, filtered, and dried to obtain NBR-grafted modified silica;
[0022] (3) Dissolve liquid nitrile rubber in toluene to prepare a 10wt% solution. Add sodium periodate at 0.5% of the mass of the liquid nitrile rubber and stir for 2 hours to oxidize the terminal hydroxyl groups of the liquid nitrile rubber to aldehyde groups. Add water to remove unreacted oxidant, separate the organic phase to obtain a toluene solution of aldehyde-terminated liquid nitrile rubber, and evaporate the toluene under reduced pressure at 60℃ to obtain aldehyde-terminated liquid nitrile rubber.
[0023] (4) By mass, take 100 parts of Emulcril 3350 and add it to the internal mixer, then add 25 parts of aldehyde-terminated liquid nitrile rubber and 0.75 parts of adipamide, control the internal mixer temperature at 60℃ and the speed at 30 rpm, and mix for 5 min; then raise the temperature to 120℃ and continue mixing for 5 min at 40 rpm, add 1.5 parts of 2-chlorocyclopropanecarboxylic acid and 0.1 parts of DCP, then raise the temperature to 140℃ and mix for 10 min, using mechanical force and an initiator to graft cyclopropane groups onto the molecular chain of NBR; take 16 parts of modified silica and 40 parts of lithopone and mix them evenly, add them to the system and mix for 3 min to allow the filler to be evenly dispersed; cool down to below 100℃ and add 1. Two parts of antioxidant OD, 1.2 parts of antioxidant RD, 4 parts of zinc oxide, 1 part of stearic acid, 8 parts of white oil paste WIOL-W, 10 parts of softening oil TP-95, and 6 parts of petroleum resin 1102 were mixed at 125°C for 70 seconds and then discharged. The mixture was then sheeted at 140°C to form a compound. Finally, 0.8 parts of sulfur, 1.5 parts of accelerator CZ-80, and 1.5 parts of accelerator TMTD-75 were mixed with the compound for 35 seconds. After cleaning, the mixture was continued to be mixed for 40 seconds and then discharged onto a sheeter to obtain a low-hardness, ink-resistant NBR rubber compound for ink printer rollers. The rubber compound was then vulcanized at 145°C for 25 minutes to obtain the rubber material.
[0024] Example 2: The difference from Example 1 is as follows:
[0025] In step (4), the following components are included by weight: 100 parts of nitrile rubber Emulcril 3350, 10 parts of modified silica, 50 parts of lithopone, 30 parts of aldehyde-terminated liquid nitrile rubber, 1.5 parts of 2-halocyclopropanecarboxylic acid, 0.8 parts of adipamide, 4 parts of white grease WIOL-W, 5 parts of softening oil TP-95, 0.5 parts of antioxidant OD, 2 parts of antioxidant RD, 3 parts of zinc oxide ZNOA, 2 parts of stearic acid SA, 5 parts of petroleum resin 1102, 1 part of sulfur, 2 parts of accelerator CZ-80, and 1 part of accelerator TMTD-75.
[0026] Example 3: The difference from Example 1 is as follows:
[0027] In step (4), by weight, the following components are included: 100 parts of nitrile rubber Emulcril 3350, 20 parts of modified silica, 30 parts of lithopone, 20 parts of aldehyde-terminated liquid nitrile rubber, 1.5 parts of 2-halocyclopropanecarboxylic acid, 0.8 parts of adipamide, 10 parts of white grease WIOL-W, 15 parts of softening oil TP-95, 2 parts of antioxidant OD, 0.5 parts of antioxidant RD, 5 parts of zinc oxide ZNOA, 1 part of stearic acid SA, 8 parts of petroleum resin 1102, 1 part of sulfur, 1 part of accelerator CZ-80, and 2 parts of accelerator TMTD-75.
[0028] Comparative Example 1: The difference from Example 1 is that:
[0029] Modified silica that does not use NBR grafting;
[0030] By weight, 100 parts of Emulcril 3350 were added to a mixer, followed by 25 parts of aldehyde-terminated liquid nitrile rubber and 0.75 parts of adipamide. The mixer temperature was controlled at 60°C and the speed at 30 rpm for 5 minutes. The temperature was then raised to 120°C and the mixing continued for 5 minutes at 40 rpm. 1.5 parts of 2-chlorocyclopropanecarboxylic acid and 0.1 parts of DCP were added, and the temperature was raised to 140°C for 10 minutes. Through mechanical force and an initiator, cyclopropane groups were grafted onto the NBR molecular chain. 16 parts of silica, 2 parts of silane coupling agent SI-69, and 40 parts of lithopone were mixed evenly and added to the system. The mixture was then mixed for 3 minutes to ensure uniform dispersion of the filler. The temperature was then lowered to below 100°C. Add 1.2 parts antioxidant OD, 1.2 parts antioxidant RD, 4 parts zinc oxide, 1 part stearic acid, 8 parts white oil paste WIOL-W, 10 parts softening oil TP-95, and 6 parts petroleum resin 1102. Mix at 125℃ for 70 seconds and unload. Then, extrude the mixture onto a cutting machine at 140℃ to form a compound. Finally, add 0.8 parts sulfur, 1.5 parts accelerator CZ-80, and 1.5 parts accelerator TMTD-75 to the compound and mix for 35 seconds. After cleaning, continue mixing for 40 seconds and unload the mixture onto a cutting machine to form a sheet. Discharge the rubber to obtain a low-hardness, ink-resistant NBR rubber compound for ink printer rollers. Cure the rubber compound at 145℃ for 25 minutes to obtain the rubber material.
[0031] Comparative Example 2: The difference from Example 1 is that:
[0032] By weight, 100 parts of Emulcril 3350 were added to a mixer, followed by 25 parts of liquid nitrile rubber, 1.5 parts of 2-chlorocyclopropanecarboxylic acid, and 0.1 parts of DCP. The mixture was then heated to 140°C and mixed for 10 minutes. Through mechanical force and an initiator, cyclopropane groups were grafted onto the NBR molecular chain. 16 parts of modified silica and 40 parts of lithopone were mixed evenly and added to the system, then mixed for 3 minutes to ensure uniform dispersion of the filler. The temperature was lowered to below 100°C, and 1.2 parts of antioxidant OD, 1.2 parts of antioxidant RD, 4 parts of zinc oxide, 1 part of stearic acid, and 8 parts of white oil were added. Mix WIOL-W paste, 10 parts softening oil TP-95, and 6 parts petroleum resin 1102 at 125℃ for 70 seconds, then discharge the mixture at 140℃ onto a sheet cutter to produce a compound. Finally, mix 0.8 parts sulfur, 1.5 parts accelerator CZ-80, and 1.5 parts accelerator TMTD-75 with the compound for 35 seconds, then clean and continue mixing for 40 seconds before discharging onto a sheet cutter to obtain a low-hardness, ink-resistant NBR rubber compound for ink-printer rollers. Cure the rubber compound at 145℃ for 25 minutes to obtain the rubber material.
[0033] Comparative Example 3: The difference from Example 1 is that:
[0034] By weight, add 100 parts of Emulcril 3350 to a mixer, then add 25 parts of aldehyde-terminated liquid nitrile rubber and 0.75 parts of adipamide. Control the mixer temperature at 60℃ and the speed at 30 rpm, and mix for 5 minutes. Then raise the temperature to 120℃ and continue mixing for 5 minutes at 40 rpm. Take 16 parts of modified silica and 40 parts of lithopone, mix them evenly, add them to the system, and mix for 3 minutes to ensure the filler is evenly dispersed. Cool down to below 100℃, then add 1.2 parts of antioxidant OD, 1.2 parts of antioxidant RD, 4 parts of zinc oxide, 1 part of stearic acid, and 8 parts of white paste. WIOL-W, 10 parts softening oil TP-95, and 6 parts petroleum resin 1102 were mixed at 125°C for 70 seconds and then discharged. The mixture was then sheeted out at 140°C to form a compound. Finally, 0.8 parts sulfur, 1.5 parts accelerator CZ-80, and 1.5 parts accelerator TMTD-75 were mixed with the compound for 35 seconds. After cleaning, the mixture was continued to be mixed for 40 seconds and then discharged onto a sheeter to obtain a low-hardness, ink-resistant NBR rubber compound for printer rollers. The rubber compound was then vulcanized at 145°C for 25 minutes to obtain the rubber material.
[0035] Comparative Example 4: The difference from Example 1 is that:
[0036] By weight, add 100 parts of Emulcril 3350 to a mixer, then add 25 parts of liquid nitrile rubber, control the mixer temperature at 60℃ and the speed at 30 rpm, and mix for 5 minutes; mix 16 parts of modified silica, 2 parts of silane coupling agent SI-69 and 40 parts of lithopone evenly, add to the system and mix for 3 minutes; add 1.2 parts of antioxidant OD, 1.2 parts of antioxidant RD, 4 parts of zinc oxide, 1 part of stearic acid, 8 parts of white oil paste WIOL-W, 10 parts of softening oil TP-95, and 6 parts of stone Oleoresin 1102 was mixed at 125℃ for 70 seconds and then discharged. The mixture was then sheeted out at 140℃ to form a compound. Finally, 0.8 parts of sulfur, 1.5 parts of accelerator CZ-80, and 1.5 parts of accelerator TMTD-75 were mixed with the compound for 35 seconds. After cleaning, the mixture was continued to be mixed for 40 seconds and then discharged onto a sheeter to obtain a low-hardness, ink-resistant NBR rubber compound for printer rollers. The rubber compound was then vulcanized at 145℃ for 25 minutes to obtain the rubber material.
[0037] Example Sample Testing:
[0038] The hardness, tensile strength, and elongation at break of the rubber materials in each embodiment and comparative example were tested to evaluate their basic mechanical properties. The results are shown in Table 1.
[0039] Table 1:
[0040] project Hardness (Shore A) Tensile strength (MPa) Elongation at break (%) Example 1 24 12.63 653 Example 2 24 11.76 685 Example 3 25 12.94 649 Comparative Example 1 32 9.07 505 Comparative Example 2 26 9.54 663 Comparative Example 3 27 9.92 587 Comparative Example 4 29 9.13 728
[0041] As can be seen from Table 1, the mechanical properties of Examples 1 to 3 are all superior to those of the comparative examples. In particular, they all have high tensile strength and elongation at break while maintaining a low hardness level, thus solving the problem of difficulty in balancing low hardness and mechanical properties.
[0042] Comparative Example 1, using ordinary silica and SI69, suffers from insufficient filler compatibility, resulting in a significant decrease in the overall performance of the product. While Comparative Example 2, using ordinary liquid nitrile butadiene, exhibits good hardness and elongation at break, its strength is compromised. Comparative Example 3, lacking the auxiliary effect of cyclopropane, loses the bridging effect generated by the temporary polarity enhancement during the internal mixing stage, leading to decreased filler dispersibility and a noticeable decline in mechanical properties.
[0043] Type A specimens were prepared from each embodiment and comparative example. The test temperature was set at 70°C and the test time was 16 hours. The compression set at high temperature was tested to evaluate the elastic recovery ability under long-term compressive load. Ink was used as the test liquid medium, and an immersion test was conducted at 40°C for 72 hours. The volume change rate was measured to evaluate the degree of swelling of the product in the ink medium and the precipitation of components. The results are shown in Table 2.
[0044] Table 2:
[0045] Compression set (%) Volume change rate (%) Example 1 9.8 3.0 Example 2 10.5 3.3 Example 3 9.6 2.9 Comparative Example 1 16.3 4.8 Comparative Example 2 18.7 6.4 Comparative Example 3 15.6 4.2 Comparative Example 4 22.2 8.3
[0046] As can be seen from Table 2, the modified silica grafted with NBR in each embodiment, the dynamic crosslinking of hydrazone bonds and the mechanochemical effect of cyclopropane improved the crosslinking strength, significantly improved the dispersibility and bonding strength between fillers and additives in the network, reduced the ink volume change rate to about 3, and reduced the compression set from 22.4 to 9.0, achieving a significant performance improvement.
[0047] In the examples, NBR-grafted modified silica effectively disperses lithopone, while ordinary silica in Comparative Example 1 fails to disperse it. The agglomeration of silica and lithopone creates minor defects that facilitate solvent penetration and result in an uneven network, leading to a significant decrease in compression set and ink resistance. In Comparative Example 2, free LNBR fails to aid elastic recovery, and the plasticizer extraction problem remains unresolved, resulting in a significant increase in compression set and volume change rate. In Comparative Example 3, decreased intermolecular forces lead to increased ink resistance and compression set.
[0048] Based on the test results in Tables 1 and 2, it can be seen that the present invention has excellent basic physical properties and resistance to compressive deformation, good long-term ink resistance, and is suitable for use as NBR material for low-hardness ink-resistant printer rollers.
[0049] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this invention.
Claims
1. A method for preparing a low-hardness, ink-resistant NBR rubber compound for printer rollers, characterized in that, Includes the following steps: Amino-modified silica is obtained by amino-modifying fumed silica with amino silane; amino-modified fumed silica is then fully dissolved and reacted with α-bromoisobutyryl bromide at low temperature to obtain initiator-grafted fumed silica; initiator-grafted fumed silica is then emulsion polymerized with butadiene and acrylonitrile monomers to obtain NBR-grafted modified fumed silica; and nitrile rubber, aldehyde-terminated liquid nitrile rubber, and adipylhydrazine are compounded and crosslinked to form hydrazone bonds. Grafting is performed by adding 2-halocyclopropanecarboxylic acid; modified silica and inorganic pigments are mixed evenly and then added to the system and mixed evenly; plasticizer, antioxidant, compounding agent, vulcanizing agent and accelerator are added, and the mixture is kneaded evenly and then discharged to obtain the final product.
2. The method for preparing the low-hardness, ink-resistant NBR rubber compound for printer rollers according to claim 1, characterized in that, The aminosilane accounts for 0.2-0.5% of the silica by mass; the α-bromoisobutyryl bromide accounts for 0.2-0.6% of the silica by mass; and the sum of the masses of butadiene and acrylonitrile monomers is in a mass ratio of 50-70:1 to the initiator-grafted silica.
3. The method for preparing the low-hardness, ink-resistant NBR rubber compound for printer rollers according to claim 1, characterized in that, The 2-halocyclopropane carboxylic acid includes one or more of 2-chlorocyclopropane carboxylic acid, 2-bromocyclopropane carboxylic acid, or 2-fluorocyclopropane carboxylic acid.
4. The method for preparing the low-hardness, ink-resistant NBR rubber compound for printer rollers according to claim 1, characterized in that, The plasticizer includes one or more of dibutyl diglyceride, trioctyl trimellitate, dioctyl terephthalate, dioctyl sebacate, or dioctyl adipate; the antioxidant includes one or more of octyl diphenylamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, 2-mercaptobenzimidazole, or styrene-modified phenol; the accelerator includes one or more of N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, dibenzothiazole disulfide, tetramethylthiuram disulfide, tetramethylthiuram monosulfide, zinc diethyldithiocarbamate, or 1,3-diphenylguanidine.
5. The method for preparing the low-hardness, ink-resistant NBR rubber compound for printer rollers according to claim 1, characterized in that, Add nitrile rubber to a mixer, then add aldehyde-terminated liquid nitrile rubber and adipamide, controlling the mixer temperature at 50-70℃ and mixing for 3-10 minutes; then raise the temperature to 110-130℃ and continue mixing for 3-10 minutes; add 2-halocyclopropanecarboxylic acid and dicumyl peroxide, then raise the temperature to 130-150℃ and mix for 8-12 minutes, using mechanical force and an initiator to graft cyclopropane groups onto the NBR molecular chain; add modified silica and disperse evenly; cool to below 100℃, add antioxidants and compounding agents, and finally add sulfur and accelerators, mix evenly, and discharge the rubber.
6. The method for preparing the low-hardness, ink-resistant NBR rubber compound for printer rollers according to claim 5, characterized in that, The mass ratio of dicumyl peroxide to 2-halocyclopropane carboxylic acid is 1:0.05~0.
15.
7. The method for preparing the low-hardness, ink-resistant NBR rubber compound for printer rollers according to claim 1, characterized in that, Amino-containing silica is fully dispersed and prepared into a solution of 3-8 g / L. Triethylamine, accounting for 0.1-0.15% of the mass of amino-containing silica, is added. α-Bromoisobutyryl bromide is added dropwise at 0-5℃, and the reaction is maintained at this temperature for 20-30 h to obtain initiator-grafted silica.
8. The method for preparing the low-hardness, ink-resistant NBR rubber compound for printer rollers according to claim 1, characterized in that, Sodium dodecyl sulfate was used to prepare an aqueous solution; initiator-grafted silica was dispersed in toluene, and sodium dodecyl sulfate aqueous solution was added to emulsify; butadiene and acrylonitrile monomer were added, followed by copper salt, tertiary amine catalyst, and ascorbic acid, and the reaction was carried out at 50-70℃ for 20-30 h; after demulsification, the product was collected and dried to obtain NBR-grafted modified silica.
9. The method for preparing the low-hardness, ink-resistant NBR rubber compound for printer rollers according to claim 1, characterized in that, Liquid nitrile rubber was dissolved in toluene, and sodium periodate (0.3-0.8% of the mass of the liquid nitrile rubber) was added. The mixture was stirred and reacted for 1-3 hours. Water was added to dissolve and remove unreacted oxidant. The organic phase was separated, and the solvent was removed by vacuum distillation to obtain aldehyde-terminated liquid nitrile rubber.
10. A low-hardness, ink-resistant NBR rubber compound for ink-printer rollers prepared by the method according to any one of claims 1 to 9, characterized in that, By weight, it comprises the following components: 80-120 parts nitrile rubber, 20-30 parts liquid nitrile rubber, 10-20 parts modified silica, 30-50 parts inorganic pigment, 15-25 parts plasticizer, 1-4 parts antioxidant, 1-2 parts 2-halocyclopropanecarboxylic acid, 0.6-0.9 parts adipylhydrazide, 0.5-2 parts vulcanizing agent, 1.5-4 parts accelerator, and 3.5-7 parts activator.