Preparation method of high-temperature-resistant and anti-aging butyl rubber

Abstract

The invention discloses a preparation method of high-temperature-resistant anti-aging butyl rubber, which comprises the following steps of: firstly, sequentially adding raw rubber and carbon black step by step at a relatively low-temperature banburying stage, coating the carbon black by virtue of a functional additive to avoid aggregation of the carbon black and reduce steric hindrance, then adding part of naphthenic oil, and uniformly mixing to obtain the high-temperature-resistant anti-aging butyl rubber. Stearic acid, zinc oxide, an anti-aging agent and the rest naphthenic oil are added, multi-stage dispersion internal mixing is achieved, and the rubber discharging temperature is strictly controlled to be smaller than or equal to 100 DEG C; adding an accelerant DM, p-quinone dioxime and manganese dioxide in a low-temperature open milling stage, and standing after thin-passing for multiple times, so as to obtain uniformly dispersed rubber compound; and finally vulcanizing and forming on a flat plate. According to the method, through a coupling process of low temperature, step-by-step oil feeding and functional additive pre-dispersion, the rubber with comprehensive performance of high temperature resistance and aging resistance is obtained, the problems that a polar vulcanizing agent is wrapped by naphthenic oil and is scorched in the early stage are avoided, and the rubber is obviously superior to a traditional one-step rubber compound; and meanwhile, a process window is wide and energy consumption is low.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rubber materials, in particular to a preparation method of high-temperature-resistant and anti-aging butyl rubber. BACKGROUND

[0002] The limitations of traditional butyl rubber vulcanization system, butyl rubber (IIR) has excellent air tightness and aging resistance due to its highly saturated molecular chain, and is widely used in long-term heat-resistant and medium-resistant occasions such as automobile inner tube, medical rubber plug, and chemical corrosion-resistant lining. However, the existing butyl formula generally uses sulfur-promoter system (CZ / DM / TMTD, etc.) for vulcanization. The cross-linking bond generated by this system is mainly polysulfide bond, which has the following defects: poor thermal stability: polysulfide bond has low bond energy, which is easy to break-recombine at above 100°C, resulting in a decrease in cross-linking density and an increase in compression permanent deformation; high-temperature reversion tendency: after long-term high-temperature service, the product surface is prone to "tacky" or a sharp decrease in hardness; high gas permeability: the flexibility of polysulfide bond segment is large, and the free volume is large, which is difficult to meet the stringent requirements of aviation, aerospace, long-distance oil pipeline, etc. on ultra-low gas permeability.

[0003] Exploration and bottlenecks of resin vulcanization system, in order to overcome the shortcomings of sulfur system, in recent years, resin vulcanization technology using phenolic resin, maleimide resin or p-quinone dioxime (GMF) as vulcanizing agent has appeared. Its mechanism is to realize cross-linking through carbon-carbon bond, ether bond or C=N bond, which has high bond energy and good thermal stability. However, this route still has the following problems: low vulcanization activity: when p-quinone dioxime is used alone, the reaction starts at a high temperature and has a long vulcanization induction period, and thick products are prone to "core under-vulcanization"; poor scorch safety: resin system is prone to premature cross-linking during high-temperature mixing or extrusion, resulting in difficult equipment cleaning and reduced product yield; lack of synergistic system: although lead oxide can activate p-quinone dioxime, high dosage of lead oxide will increase the density of the rubber compound and increase the environmental risk, and there is a lack of guidance on the synergistic ratio with the general accelerator DM.

[0004] With the rapid development of new energy hydrogen fuel cells, deep-sea oil and gas pipelines, and high-temperature chemical valve sealing elements, the market has put forward comprehensive performance indicators of "≥120°C continuous use, gas permeability ≤2×10 -7 cm 3 ·cm / (cm 2 ·s·Pa), compression permanent set ≤20%" for butyl rubber products. However, the existing sulfur system or single resin system cannot meet the above requirements at the same time. SUMMARY

[0005] In order to solve the above problems, the present application provides a preparation method of high-temperature-resistant and anti-aging butyl rubber.

[0006] The method uses butyl rubber as the base material and DM-p-quinone dioxime-lead oxide as the new formula of the synergistic resin vulcanization system to achieve high energy crosslinking network, low air permeability and long service life sealing performance of butyl rubber material.

[0007] A high-temperature-resistant and anti-aging butyl rubber composition, taking 100 parts by weight of butyl rubber 1675 as the base material, and the following components are mixed: Carbon black N330 30-50 parts by weight; Stearic acid 1.8-2.2 parts by weight; Zinc oxide 4.5-5.5 parts by weight; Anti-aging agent RD 1-1.5 parts by weight; Anti-aging agent 4010NA 1-1.5 parts by weight; Naphthenic oil 5.5-6.5 parts by weight; Accelerator DM 0.8-4 parts by weight; p-quinone dioxime 1.2-1.5 parts by weight; Lead oxide or manganese dioxide 1-5 parts by weight; And optional functional additives, the functional additives include: Zinc soap of fatty acid 0.8-1.2 parts by weight, and Nano calcium carbonate 1.5-2.5 parts by weight; The average particle size of the nano calcium carbonate is ≤50 nm.

[0008] Further, the amount of the accelerator DM is 3-4 parts by weight.

[0009] Further, the amount of the carbon black N330 is 40-50 parts by weight.

[0010] A preparation method of a high-temperature-resistant and anti-aging butyl rubber, comprising the following steps: S1, mixing in an internal mixer: set the initial temperature of the internal mixer to 50-60℃ and the rotation speed to 22-25 rpm; first, add butyl rubber and functional additive 1-2 min; then add the carbon black premix and plasticize for 1-2 min; then add stearic acid, zinc oxide, and anti-aging agent and mix for 1-2 min; add naphthenic oil in two slow feeding steps, and the total mixing time is 8-10 min; the discharge temperature is controlled below 100℃, and the discharge is cooled at room temperature; S2, mixing in an open mill: set the roller temperature of the open mill to ≤60℃; first, plasticize for 2-3 times; then add accelerator DM, p-quinone dioxime, and lead oxide or manganese dioxide, and turn the rubber left and right for 3 times each; then, after thinning for 6-8 times, discharge the material; and then, store it at room temperature for 12 h to obtain a mixed rubber sheet. S3, vulcanization: the mixing rubber sheet of step S2 is placed on a flat vulcanization machine for vulcanization, and finally the target product is obtained, the vulcanization temperature is 150℃, and the vulcanization time is 15 min; In the step S1, the naphthenic oil is added twice, 40-60wt% of the total amount is added 1-2min after the carbon black premix is put in, and the remaining part is added in the internal mixer after the stearic acid, zinc oxide, and antioxidant are put in.

[0011] Further, in the step S2, the initial roll temperature of the open mill is 45-55℃, and the surface temperature of the rubber is controlled below 75℃ in the thin pass stage.

[0012] Further, in the step S1, the antioxidant includes antioxidant RD and antioxidant 4010NA.

[0013] Further, in the step S1, the functional additive one is zinc stearate, the premix of the carbon black premix is a mixture of carbon black and functional additive two, the functional additive two is nano calcium carbonate, and the average particle size of the nano calcium carbonate is ≤50nm.

[0014] Further, in the step S1, when the carbon black in the carbon black premix is 50wt% of the total amount of butyl rubber, the carbon black is added twice, 50wt% of the total amount of carbon black is added 1-2min after the butyl rubber is put in, the 50wt% of carbon black is mixed with nano calcium carbonate in advance to obtain a carbon black premix, and then put into the internal mixer; the remaining part of the carbon black is put into the internal mixer together with the naphthenic oil put in the first time.

[0015] The preparation method of the high-temperature-resistant and anti-aging butyl rubber relates to a specific formula, and comprises the following steps, S1, mixing: the initial temperature of the internal mixer is set to 50-60℃, and the rotating speed is 22-25 rpm; 100 parts by weight of butyl rubber 1675 and 1 part by weight of zinc stearate are first put in and premixed for 1 min; 30 parts by weight of carbon black premix is then put in and plasticated for 2-3 min; 20 parts by weight of carbon black and 3 parts of naphthenic oil are then added and mixed for 2 min; then 2 parts by weight of stearic acid, 5 parts by weight of zinc oxide and 2 parts by weight of antioxidant are sequentially added to the internal mixer and mixed for 1 min, and then 3 parts by weight of naphthenic oil is added and mixed for 2-3 min; the total mixing time in the mixing stage is 8-10 min, and the discharge temperature is controlled below 100℃; and after discharging, the rubber is cooled at room temperature; S2, open mill mixing: the roll temperature of the open mill is set to ≤60℃, the rubber is plasticated for 2-3 times, then 4 parts by weight of accelerator, 1.5 parts by weight of p-quinone dioxime, and 5 parts by weight of manganese dioxide are added, and the rubber is turned left and right for 3 times each; then the rubber is thin passed for 6-8 times and discharged, and then stored at room temperature for 12 h to obtain a mixing rubber sheet; S3, vulcanization: the mixing rubber sheet of step S2 is placed on a flat vulcanization machine to perform vulcanization, and finally the target product is obtained, the vulcanization temperature is 150℃, the vulcanization pressure is 12MPa, and the vulcanization time is 15min.

[0016] Further, in the step S1, when 30 parts by weight of the carbon black premix is put into the internal mixer, it is first plasticated in the internal mixer for 1min, then the upper ram of the internal mixer is lifted for cleaning, and then it is continued to be mixed for 2min.

[0017] Further, in the step S1, when the naphthenic oil is put in for the second time, all the mixture is mixed in the internal mixer for 1min, then the upper ram of the internal mixer is lifted for cleaning, and then it is continued to be mixed for 30-60s until the temperature is 100℃.

[0018] Further, in the step S1, the carbon black is N330, and the carbon black premix is 30 parts by weight of carbon black N330 and 2 parts by weight of nano calcium oxide mixed in advance for 1min.

[0019] Further, in the step S1, the antioxidant includes 1 part by weight of antioxidant RD and 1 part by weight of antioxidant 4010NA, and in the step S2, the accelerator is accelerator DM.

[0020] Compared with the prior art, the butyl rubber prepared by the preparation method has the beneficial effects that, 1. Butyl rubber is a low unsaturated rubber, which is much more difficult to vulcanize than NR and SBR, and the present application selects accelerator DM, p-quinone dioxime and lead oxide as vulcanizing agents, and the resin vulcanization system is mainly formed by high-energy carbon-carbon bonds and ether bonds, which have high bond energy and good thermal stability, forming a stable crosslinked network, which significantly improves the heat aging resistance and air tightness compared with the polysulfide bond of sulfur vulcanization system. The crosslinked structure is more stable in long-term high-temperature environment, and the physical property retention rate is higher; at the same time, the dense network more effectively blocks gas permeation, so that the product has longer service life and more reliable sealing performance.

[0021] 2. The method adopts low temperature-low speed and step-by-step premixing, and the functional additive "pre-occupies" the technical means, that is, the zinc soap of fatty acid and butyl rubber are put in at the same time under the condition of 50-60℃ and 25rpm, and then the nano CaCO3 and part of the carbon black are mixed and added, so that the dispersant and the spacer particles form a synergistic coating layer wrapped in the carbon black, avoiding the carbon black pores being occupied by ZnO and stearic acid in advance, reducing the Payne effect, and significantly improving the crosslinking reaction efficiency of the subsequent quinone oxime, so that the crosslinking density is improved, and the rubber product has excellent medium resistance.

[0022] 3. Add naphthenic oil in stages to avoid agglomeration of high-part carbon black. The naphthenic oil is added in two stages: the first stage is added after the carbon black premix, and the second stage is added simultaneously with the inorganic components. The oil molecules first penetrate into the aggregates and are then sheared open by the outside, so that the 50 phr N330 maintains the same dispersion level as the 30 phr.

[0023] 4. Strictly control the discharge temperature to ≤102℃ and the open mixing temperature to ≤60℃ for double low-temperature chain, eliminating the problem of quinone oxime scorching. The final mixing temperature is strictly controlled below 102℃. The initial rolling temperature of the open mixing is ≤60℃ and water cooling is provided. The surface temperature of the rubber compound during the thin-pass stage is ≤75℃. The GMF decomposition temperature window is completely avoided, tc10 is extended, and there is no risk of early vulcanization after a 12-hour production stoppage, making it suitable for large-scale production line operation in summer.

[0024] Therefore, the butyl rubber preparation method proposed in this invention can obtain rubber with comprehensive properties of high temperature resistance and anti-aging through a coupled process of low temperature-step oil feeding-functional additive pre-dispersion, which is an improvement over the traditional sulfur system product. Detailed Implementation

[0025] The technical solution 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.

[0026] Butyl rubber (IIR) is a linear, gel-free copolymer (i.e., unbranched, and uncrosslinked in uncured form). It is produced by ionic polymerization of isobutylene and a small amount of isoprene. Butyl rubber is a low-unsaturated rubber, and its vulcanization process is much more difficult than that of natural rubber (NR) and styrene-butadiene rubber (SBR). Therefore, a highly efficient accelerator should be selected for the vulcanization system, and high-temperature, long-time vulcanization is required. During vulcanization, sulfur crosslinks on the isoprene molecules to form polysulfide bonds or monosulfide bonds.

[0027] This invention provides a high-temperature resistant and anti-aging butyl rubber material, comprising the following components in parts by weight: 100 parts butyl rubber, 2 parts stearic acid, 2 parts antioxidant, 5 parts zinc oxide, 50 parts carbon black, 6 parts dispersant, 0.8 parts accelerator, 1.2 parts p-quinone dioxime, and 1 part lead oxide.

[0028] Butyl rubber grades include 1675. "16" indicates that the degree of unsaturation is about 1.6% (range 1.6±0.2%), and the last two digits "75" indicate that the Mooney viscosity is about 75 (Mouney viscosity is an indicator of the fluidity of rubber; the higher the value, the harder the rubber).

[0029] Antioxidants, including any one or combination of N-cyclohexyl-N'-phenyl-p-phenylenediamine (antioxidant 4010), N-phenyl-N'-isopropyl-p-phenylenediamine (antioxidant 4010NA), N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (antioxidant 4020), 2,2,4-trimethyl-1,2-dihydroquinoline polymer (antioxidant RD), 2-mercaptobenzimidazole (antioxidant MB).

[0030] Carbon black is ASTM-N series carbon black, including N220, N330, etc.

[0031] Accelerators, the vulcanization accelerator includes any one or combination of N cyclohexyl 2 benzothiazole sulfenamide (accelerator CZ), 2 mercaptobenzothiazole (accelerator M), benzothiazole disulfide (accelerator DM) or tetramethyl thiuram disulfide (accelerator TMTD).

[0032] The rubber performance detection method adopted by the present application is as follows: The stress at a given elongation is the stress that a material will experience or return when it is stretched to a given elongation (strain) and held constant. It describes the "stress at a given elongation".

[0033] The elongation at break is the relative percentage of elongation experienced by a material when it is stretched from its initial length to the point of breakage during a tensile test. It is a key indicator of a material's ductility (toughness / stretchability).

[0034] Hardness: measured by Shore durometer method, Shore durometer method is GB / T531.1-2008 vulcanized rubber or thermoplastic rubber indentation hardness test method first part.

[0035] Tensile strength: measured by GB / T528-2009 vulcanized rubber or thermoplastic rubber tensile stress-strain properties.

[0036] Medium resistance: weigh the rubber sample to be tested, put the sample in different solvents for full immersion, according to the test requirements, put it in the oven at a specific temperature, and soak for 7 days. After soaking, take out the rubber sample and wash it with deionized water, place it on filter paper and dry naturally (1-3 h) or dry in an oven, finally weigh the sample and calculate the mass change rate: Z=(M0-M1) / M0 ×100% Where M0 is the mass of the sample before immersion, and M1 is the mass of the sample after immersion.

[0037] Test conditions: 20% hydrochloric acid (50℃*7 days), 40% sulfuric acid (85℃*7 days), 70% phosphoric acid (85℃*7 days), 40% sodium hydroxide (85℃*7 days).

[0038] Plasticity: GB / T 12828-2006 "Rubber and unvulcanized compounds Determination of plasticity and recovery - Parallel plate method" is used to determine the plasticity of rubber using a plasticity tester (parallel plate method).

[0039] Plasticity P = (h 0- h1) / (h0+h1), h0: initial thickness, h1: height after compression.

[0040] Example 1 This example uses butyl rubber as the base rubber to prepare a high-temperature-resistant and anti-aging butyl rubber material. The components include the following by weight: 100 parts of butyl rubber 1675, 40 parts of carbon black N330, 2 parts of stearic acid, 5 parts of zinc oxide, 1 part of antioxidant RD, 1 part of antioxidant 4010NA, 6 parts of naphthenic oil, 0.8 parts of accelerator DM (benzothiazole disulfide), 1.2 parts of p-quinone dioxime, and 1 part of lead oxide.

[0041] The process steps for preparing the rubber from the above components are as follows: S1, internal mixing, set the initial temperature of the internal mixer to 50-60℃, and the speed to 22-25 rpm. First, put 100 parts by weight of butyl rubber masterbatch and 50 parts by weight of carbon black 330 into the internal mixer, and plasticize for 2-3 min. Then, sequentially add 2 parts by weight of stearic acid, 5 parts by weight of zinc oxide, and 2 parts by weight of antioxidant into the internal mixer, and continue to mix for 2-3 min. Finally, add 6 parts by weight of plasticizer naphthenic oil into the internal mixer, and continue to mix for 3-5 min. Lift the upper ram of the internal mixer for cleaning, and continue to mix for 30-60 s until the temperature reaches 100℃ (mixing at 100℃ ensures sufficient dispersion but avoids scorching). Perform discharge to obtain a rubber sheet, and cool at room temperature after discharge.

[0042] S2, open mixing, control the temperature of the open mill at 40-60℃ (to prevent premature vulcanization), and adjust the roll gap to 1.5 mm. First, add the rubber sheet obtained in step S1 into the open mill and plasticize for 2-3 passes (about 5-10 min). Then, add 2 parts by weight of accelerator, 1.2 parts by weight of p-quinone dioxime, and 1 part by weight of lead oxide, and turn the rubber left and right for three times each. Finally, adjust the roll gap of the open mill to 0.2 mm for thin pass 6-8 times, and discharge. Stop for 12 h at room temperature (to promote stress relaxation and migration of the compounding agents), and obtain the mixed rubber.

[0043] S3, vulcanization, the rubber compound is vulcanized on a flat vulcanizing machine at 150°C, 15 min, pressure 12 MPa, to obtain a vulcanized rubber test piece.

[0044] In the above steps, in the mixing stage of step S1, the butyl rubber masterbatch and carbon black are plasticized in the internal mixer at 50-60°C, the Mooney of butyl 1675 is about 45-55, and the initial viscosity at 50-60°C is sufficient to "eat" 40 parts of N330 at one time without forming a ball, that is, the shear force of the high-viscosity raw rubber is used to break the carbon black aggregates. In this process, the peak current falls by ≤10%, the power curve is smooth, the compound is balled and the surface is free of visible carbon black dust, that is, the dispersibility is ≥95%.

[0045] When the above high-viscosity raw rubber mixture coats the rotor, the small materials such as stearic acid, zinc oxide, and antioxidant are added in turn. The small materials can be quickly dispersed. The stearic acid is added first, which lubricates the compound and reduces the internal temperature peak, and at the same time, it "saponifies" part of the surface of the carbon black, providing a dispersion site for zinc oxide. Zinc oxide is added next. Zn 2 ⁺ immediately forms a soluble zinc soap with stearic acid, increasing the dispersion speed; if ZnO is added first, it is easy to form hard agglomerates of 2-5 μm due to its high surface polarity, which is difficult to break down later. The antioxidant is added last. The amine in the antioxidant has a low melting point, and adding it last can avoid being adsorbed by zinc oxide to reduce the effective concentration and reduce early volatilization.

[0046] The initial temperature of the internal mixer is set to 50-60°C, and the rotor generates heat, increasing by about 5°C per 1 min. Therefore, after 2-3 min of plasticizing the first batch of rubber and carbon black, the temperature of the internal mixer is between 75±5°C, and after 2-3 min of plasticizing the second batch of small materials such as stearic acid, the temperature of the internal mixer is between 90±5°C. After 3-5 min of plasticizing the third batch of naphthenic oil, the temperature of the internal mixer is between 95-100°C. Once the oil is added, the viscosity of the system drops sharply; if the oil is added too early, the carbon black will form a structure with a soft outside and a hard inside due to "oil-encapsulated carbon", and the dispersibility will decrease. Adding naphthenic oil last in the small materials can use the high shear in the early stage to break down the carbon black structure, and then use the oil to adjust the viscosity, promote dispersion, and reduce heat generation. Due to the large weight fraction of naphthenic oil, the plasticizing time is longer, and the temperature during the naphthenic oil input stage needs to be controlled to reduce the raw rubber temperature and reduce heat generation, avoid premature reaction or balling of small materials such as zinc oxide and antioxidant due to local overheating, and also avoid the critical decomposition temperature of quinone oxime vulcanizing agents (≈120°C) to prevent early scorching. The rubber is discharged at 100°C, at which point the carbon black is fully infiltrated and the dispersibility is above 95%, and the surface of the compound is smooth; and it is still below the activation temperature of the accelerant DM and p-quinone dioxime (DM ≈ 110°C, GMF ≈ 120°C), ensuring that there is no crosslinking in the masterbatch stage.

[0047] According to the above parameters, even if stirring for 4 minutes, the out-gum temperature can be stably controlled at 100±2℃, the risk of scorching remains unchanged, and the dispersion can still be maintained at more than 95%.

[0048] In the open mill stage of step S2, the uniformly dispersed master batch sheet obtained in step (1) is put into an open mill at 40-60℃. This is because, when the roller temperature is higher than 40℃, the sheet can be smoothly wrapped on the roller without brittle fracture. When the temperature is lower than 60℃, the viscosity of the system is high enough after the addition of the accelerator / vulcanizing agent, which is because, firstly, the accelerators DM (melting point 154℃) and GMF (melting point 123℃) are still in the form of solid microcrystals at 40-60℃, but the particle size is usually ≤75μm; secondly, when the sheet is 0.2 mm thick, the local shear rate at the roller gap is 10 3 –10 4 s -1 , and the mechanical force generated is sufficient to further grind the particles (DM and GMF) to 1-3μm and adhere them to the rubber chain, realizing micron-level dispersion of the solid phase.

[0049] Prevent premature reaction at low temperature, the critical activation temperature of DM is about 110℃, and the temperature at which the GMF / lead oxide complex system starts to crosslink is more than 120℃. If the roller temperature is >80℃, the cumulative temperature rise during thinning can make the rubber locally reach 100-110℃, and the Mooney scorch t5 will be shortened by more than 30%, and "self-sulfur" particles will appear. The setting of 40-60℃ can lock the temperature of the discharged sheet within 75℃, leaving a safety margin for subsequent storage, extrusion or calendering. Eliminate scorching, and the complete crosslinking reaction is delayed to the final vulcanization stage ≥150℃. Therefore, this temperature setting not only meets the process dispersion requirements, but also ensures the safety of processing.

[0050] Stop at room temperature for 12h, let the molecular chain relax, reduce the subsequent calendering / extrusion shrinkage; make the small polar materials such as stearic acid and zinc oxide continue to migrate to the rubber-filler interface, improve the interface bonding, and at the same time let a small amount of residual air diffuse out, so that the temperature of the final mixed rubber is ≤25℃, avoiding premature crosslinking.

[0051] Therefore, the process of the embodiment adopts the "oil first and then sulfur" sequence, first disperses the carbon black and small materials thoroughly with high shear, then adjusts the viscosity and cools the rubber with oil, and then adds the accelerator, GMF and lead oxide respectively in the low-temperature open mill stage, to ensure uniformity of each component and avoid early scorching.

[0052] Example 2 This embodiment uses butyl rubber as the base rubber to prepare a high-temperature-resistant and anti-aging butyl rubber material. The components include the following by weight: butyl rubber 1675 is 100 parts, carbon black N330 is 30 parts, stearic acid is 2 parts, zinc oxide is 5 parts, antioxidant RD is 1 part, antioxidant 4010NA is 1 part, naphthenic oil is 6 parts, accelerator DM is 4 parts, p-quinone dioxime is 1.5 parts, and manganese dioxide is 5 parts.

[0053] The process steps for preparing the rubber from the above components are as follows: S1, internal mixing, set the initial temperature of the internal mixer to 50-60°C, and the speed to 22-25 rpm. First, put the butyl rubber masterbatch and carbon black 330 into the internal mixer, and plasticize for 2-3 min. Then, sequentially add stearic acid, zinc oxide, and antioxidants into the internal mixer, and continue internal mixing for 2-3 min. Finally, add the plasticizer naphthenic oil into the internal mixer, and continue internal mixing for 3-5 min. Remove the upper pin of the internal mixer for cleaning, and continue internal mixing for 30-60 s until the temperature reaches 100°C (internal mixing at 100°C ensures sufficient dispersion but avoids scorching). Perform discharge to obtain a rubber sheet, and cool at room temperature after discharge.

[0054] S2, open mixing, control the temperature of the open mill at 40-60°C (to prevent premature vulcanization), and adjust the roll gap to 1.5 mm. First, add the rubber sheet obtained in step S1 into the open mill and plasticize for 2-3 passes (about 5-10 min). Then, add the accelerators, p-quinone dioxime, and manganese dioxide, and flip the rubber left and right for three times each. Finally, adjust the roll gap of the open mill to 0.2 mm for thin passing 6-8 times, and discharge. Stop for 12 h at room temperature (to allow stress relaxation and migration of the additives), to obtain the mixed rubber.

[0055] S3, vulcanization, vulcanize the mixed rubber on a flat vulcanization machine at 150°C, 15 min, and a pressure of 12 MPa, to obtain a vulcanized rubber test piece.

[0056] Example 3 This embodiment uses butyl rubber as the base rubber to prepare a high-temperature-resistant and anti-aging butyl rubber material. The components include the following by weight: butyl rubber 1675 is 100 parts, carbon black N330 is 40 parts, stearic acid is 2 parts, zinc oxide is 5 parts, antioxidant RD is 1.5 parts, antioxidant 4010NA is 1.5 parts, naphthenic oil is 6 parts, accelerator DM is 4 parts, p-quinone dioxime is 1.5 parts, and manganese dioxide is 5 parts, as well as functional additives, including functional additive one zinc stearate 1 part and functional additive two nano calcium carbonate (50 nm) 2 parts.

[0057] The process steps for preparing the rubber from the above components are as follows: S1, mixing, set the initial temperature of the mixer to 50-60℃, the speed is 22-25 rpm, first add the butyl rubber masterbatch and the dispersant zinc stearate, plasticize for 1 min, then add the premix of carbon black 330 and nano calcium carbonate into the mixer, mix for 1 min; lift the top bolt of the mixer to clean, continue mixing for 2 min; add 3 parts of naphthenic oil, continue mixing for 2 min; then add stearic acid, zinc oxide, antioxidant in sequence, then add the remaining 3 parts of naphthenic oil, continue mixing for 2 min; lift the top bolt of the mixer to clean, continue mixing for 30-60 s until the temperature is 100℃ (mixing at 100℃ ensures sufficient dispersion but avoids scorching), discharge the rubber sheet, and cool at room temperature after discharging.

[0058] S2, mixing, control the temperature of the mixer to 40-60℃ (to prevent premature vulcanization), adjust the roll gap to 1.5 mm, first add the rubber sheet obtained in step S1 into the mixer and plasticize for 2-3 times (about 5-10 min); then add 2 parts by weight of accelerator, 1.2 parts by weight of p-quinone dioxime and 1 part by weight of lead oxide, flip the rubber three times on the left and right; finally adjust the roll gap of the mixer to 0.2 mm for thin pass 6-8 times, then discharge, and store at room temperature for 12 h (to promote stress relaxation and migration of the compounding agent), to obtain the mixed rubber.

[0059] S3, vulcanization, vulcanize the mixed rubber on a flat vulcanizing machine at 150℃, 15 min, pressure 12 MPa, to obtain the vulcanized rubber test piece.

[0060] Example 4 In this example, butyl rubber is used as the base rubber to prepare a high-temperature-resistant and anti-aging butyl rubber material. The components include, by weight: butyl rubber 1675 100 parts, carbon black N330 50 parts, stearic acid 2 parts, zinc oxide 5 parts, antioxidant RD 1.5 parts, antioxidant 4010NA 1.5 parts, naphthenic oil 6 parts, accelerator DM 4 parts, p-quinone dioxime 1.5 parts, manganese dioxide 5 parts, and functional additives, including functional additive one zinc stearate 1 part and functional additive two nano calcium carbonate (50 nm) 2 parts.

[0061] The process steps for preparing the rubber from the above components are as follows: S1, mixing, set the initial temperature of the mixer to 50-60℃, the speed is 22-25 rpm, first add the butyl rubber masterbatch and the dispersant zinc stearate, plasticize for 1 min, then add carbon black 330 and nano calcium carbonate into the mixer, plasticize for 1 min; lift the top bolt of the mixer to clean, continue mixing for 2 min; add 3 parts of naphthenic oil, continue mixing for 2 min; then add stearic acid, zinc oxide, antioxidant in sequence, then add the remaining 3 parts of naphthenic oil, continue mixing for 2 min; lift the top bolt of the mixer to clean, continue mixing for 30-60 s until the temperature is 100℃ (mixing at 100℃ ensures sufficient dispersion but avoids scorching), discharge the rubber sheet, and cool at room temperature after discharging.

[0062] S2, mixing, control the temperature of the mixer to 40-60℃ (to prevent premature vulcanization), adjust the roll gap to 1.5 mm, first add the rubber sheet obtained in step S1 into the mixer and plasticize for 2-3 times (about 5-10 min); then add 2 parts by weight of accelerator, 1.2 parts by weight of p-quinone dioxime and 1 part by weight of lead oxide, flip the rubber three times on the left and right; finally adjust the roll gap of the mixer to 0.2 mm for thin pass 6-8 times, then discharge, and store at room temperature for 12 h (to promote stress relaxation and migration of the compounding agent), to obtain the mixed rubber.

[0063] S3, vulcanization, vulcanize the mixed rubber on a flat vulcanizing machine at 150℃, 15 min, pressure 12 MPa, to obtain the vulcanized rubber test piece.

[0064] Example 5 This example uses butyl rubber as the base rubber to prepare a high-temperature-resistant and anti-aging butyl rubber material. The components include, by weight: butyl rubber 1675 100 parts, carbon black N330 50 parts, stearic acid 2 parts, zinc oxide 5 parts, antioxidant RD 1.5 parts, antioxidant 4010NA 1.5 parts, naphthenic oil 6 parts, accelerator DM 4 parts, p-quinone dioxime 1.5 parts, manganese dioxide 5 parts, and functional additives, including functional additive one zinc stearate 1 part and functional additive two nano calcium carbonate (50 nm) 2 parts.

[0065] The process steps for preparing the rubber from the above components are as follows: S1, mixing, set the initial temperature of the mixer to 50-60℃, the speed is 22-25 rpm, first add the butyl rubber masterbatch and the dispersant zinc stearate into the mixer and mix for 1 min, then add 30 parts of carbon black 330 and nano calcium carbonate into the mixer and plasticize for 1 min; lift the top bolt of the mixer to clean, then continue mixing for 2 min; add 20 parts of carbon black 330 and 3 parts of naphthenic oil, continue mixing for 2 min; then add stearic acid, zinc oxide, antioxidant in sequence into the mixer and mix for 1 min, then add the remaining 3 parts of naphthenic oil, continue mixing for 1-2 min; lift the top bolt of the mixer to clean, then continue mixing for 30-60 s until the temperature is 100℃ (mixing at 100℃ ensures sufficient dispersion but avoids scorching), then discharge the rubber sheet and cool at room temperature.

[0066] S2, mixing, control the temperature of the mixer to 40-60℃ (to prevent premature vulcanization), adjust the roll gap to 1.5 mm, first add the rubber sheet obtained in step S1 into the mixer and plasticize for 2-3 times (about 5-10 min); then add the accelerator, p-quinone dioxime and manganese dioxide, flip the rubber three times on the left and right; finally adjust the roll gap of the mixer to 0.2 mm and pass through the mixer 6-8 times, then discharge, and store at room temperature for 12 h (to promote stress relaxation and migration of the additives), to obtain the mixed rubber.

[0067] S3, vulcanization, vulcanize the mixed rubber on a flat vulcanization machine at 150℃, 15 min, pressure 12 MPa, to obtain the vulcanized rubber test piece.

[0068] Comparative Example 1 In this example, butyl rubber is used as the base rubber, and a sulfur accelerator system is used as the vulcanization system to prepare a high-temperature-resistant and anti-aging butyl rubber material. The components include the following by weight: butyl rubber 1675 100 parts, carbon black N330 30 parts, stearic acid 2 parts, zinc oxide 5 parts, antioxidant RD 1 part, antioxidant 4010NA 1 part, naphthenic oil 6 parts, accelerator DM 1 part, accelerator TMTD 0.3, sulfur 1 part.

[0069] The process steps for preparing the rubber from the above components are as follows: S1, mixing, the initial temperature of the mixer is set to 45-55°C (the rotor and the chamber wall are both passed through 15°C cooling water), the speed is 15-18 rpm, first put the butyl rubber masterbatch and carbon black 330 into the mixer, plasticize for 2 min; then put the stearic acid, zinc oxide, antioxidant into the mixer in turn, continue mixing for 2-3 min, finally put the plasticizer naphthenic oil (about 20°C) into the mixer, continue mixing for 2-3 min; lift the upper jack of the mixer for cleaning (open 2s pressure relief to discharge heat), continue mixing for 30-60s to about 80°C (strictly control the temperature below 85°C), discharge the glue to get the rubber sheet, cool at room temperature after discharging.

[0070] S2, mixing, the temperature of the mixer is controlled at about 40°C (to prevent premature vulcanization), the roller distance is adjusted to 2mm, first put the rubber sheet obtained in step S1 into the mixer for plasticizing for 1 pass (about 2 min); then evenly scatter the DM + TMTD + sulfur pre-dispersed particles (complete within 1 min), turn the rubber left and right for three times each; finally adjust the roller distance of the mixer to 0.5mm for thin pass for 2 times (cumulative 2 min) after discharging, the rubber temperature is ≤65°C, the rubber sheet thickness is 6mm, cool in air cooling to room temperature or ≤30°C, the cooling process is about 8h (to promote stress relaxation and additive migration), get the mixed rubber.

[0071] S3, vulcanization, vulcanize the mixed rubber on the flat vulcanizing machine at 160°C, 15 min, pressure 102 MPa, get the vulcanized rubber test piece.

[0072] The performance test results of the above examples and comparative examples are shown in Table 1.

[0073] Table 1 From comparative example 1 and comparative example 1, it can be seen that the mixing window temperature of the quinone dioxime / lead oxide system (non-sulfur high-temperature stable vulcanization system) in example 1 is 15 DEG C wider than that of the sulfur / TMTD / DM system in comparative example 1, the quinone dioxime / lead oxide system has high activation energy and is obviously crosslinked at ≥120 DEG C; in actual production, 100 DEG C is set as the red line; the sulfur / super accelerator system in comparative example 1 has approached scorching at 75-80 DEG C, and must be water-cooled in summer, while the quinone dioxime / lead oxide system can be stabilized by air cooling. The number of thin passes is not limited, the quinone dioxime / lead oxide system can be passed 6-8 times at 0.2 mm, and the cumulative temperature is still 75 DEG C without self-sulfur; the sulfur / super accelerator system can only be mixed uniformly for 2 times and quickly discharged, so as to compare scorching. The tolerance of the storage time is high, the quinone dioxime / lead oxide system can be stored for more than 12 h at 30 DEG C, and the Mooney increment is less than 3%; while the sulfur / super accelerator system must be used up within 8 h, otherwise the Mooney increment is 8-10%, and the surface of the extruded product appears "sesame points". Overall, in the quinone dioxime / lead oxide system, the preparation process adopts normal temperature processing process to produce high-temperature products, while the sulfur / super accelerator system must be run at low temperature throughout the process, and the equipment investment, energy consumption, process rhythm and scrap risk are all amplified, therefore, the quinone dioxime route has great advantages in high-end heat-resistant butyl products.

[0074] Moreover, it can be found from table 1 that the tensile strength of the rubber product obtained in example 1 is better than that of comparative example 1, and the medium resistance performance is improved, which is because the quinone dioxime / lead oxide system forms high-energy carbon-carbon bonds and ether bonds, and the thermal stability is much higher than that of the polysulfide bond of the sulfur / super accelerator system, so the bond breaking, recombination (anti-sulfur) or degradation at high temperature is not easy. Through the synergistic activation of the accelerator DM and the lead oxide, the vulcanization reaction is more gentle, the induction period is prolonged, and the risk of "core undercure" of thick products is reduced. Once the resin crosslinking network is formed, it is not easy to degrade (over-sulfur) due to the extension of the vulcanization time, and the physical property retention rate is high.

[0075] In example 2, the amount of accelerator DM in the quinone dioxime / lead oxide system and the oxidizing agent are adjusted to manganese dioxide, which has a higher oxidation-reduction potential than lead oxide, and the conversion rate of GMF to p-dinitrosobenzene is improved. Due to the reduction of carbon black, the steric hindrance of the rubber chain end is reduced, so that the free radicals of p-dinitrosobenzene are more easily close to the double bonds in the rubber molecules, and the C-N-C network structure is formed faster. Therefore, after adjusting the quinone dioxime / lead oxide system, although the amount of carbon black is reduced, the performance of the rubber product does not decrease, which proves that the preparation method of example 2 can obtain rubber products with excellent performance in the quinone dioxime system with different accelerators.

[0076] In Example 3 to Example 5, the functional composite additive (1 part of zinc soaps of fatty acids and 2 parts of 50 nm CaCO3) is added in the whole formula, although the carbon black is increased to 40 parts, the zinc soaps of fatty acids are mixed with the raw rubber in advance, and the nano CaCO3 acts as a spacer particle, which can all be adsorbed or penetrated to the surface of the carbon black in advance, reducing the formation of carbon black aggregates, and the dispersion efficiency is obviously improved. The zinc soaps of fatty acids are added first as oleophilic molecules, and the surface of the nano CaCO3 is treated with fatty acids. When they exist at the same time, a synergistic coating layer can be formed to wrap around the outer layer of the carbon black, avoiding the occupation of the carbon black surface vacancies by stearic acid or zinc oxide, and weakening the dispersion effect. When the amount of carbon black is further increased to 50 parts, the carbon black can be added in two steps. The first step is to mix the carbon black and nano CaCO3 and then perform mixing and compounding, obtaining carbon black particles with a synergistic coating layer. Then, the second step is to add the carbon black and part of the naphthenic oil. The purpose of this step is to add part of the naphthenic oil before the stearic acid, ZnO, and antioxidant, and use the high permeability of the oil to expand the carbon black aggregates, fill the internal voids, reduce the strength of the aggregates, include the oil film on the surface of the synergistic coating layer, and reduce the adsorption of subsequent inorganic powders. This allows the carbon black-rubber interface to be lubricated during the strongest stage of shear, reducing the carbon black-rubber interfacial energy. In this way, multiple methods can be used to significantly reduce the steric hindrance around the double bonds in the rubber molecules. The last step is to add the naphthenic oil after the stearic acid, ZnO, and antioxidant. This allows the mixing and compounding to be performed at the end of the mixing process, reducing the shear heat generation and controlling the discharge temperature to 100°C.

[0077] In Comparative Example 2, the stearic acid, ZnO, and antioxidant are added first, and the oil is added later. Due to insufficient reduction of carbon black aggregates, the steric hindrance around the double bonds in the rubber molecules does not further decrease, making it difficult for GMF radicals to approach the double bonds in the rubber molecules during the subsequent mixing stage. On the other hand, the small particle size and high polarity of zinc oxide and stearic acid preferentially enter the carbon black voids, forming a shell-core hard group. When the naphthenic oil is added, it cannot fully penetrate. Therefore, in Example 3 to Example 4, step-by-step addition of naphthenic oil and pre-treatment of carbon black mixing with functional composite additives are used. The rubber products prepared in this way have better medium resistance and aging resistance than those in Example 2 and Example 1. When further step-by-step addition of a large amount of carbon black is used in Example 5, the carbon black is added in two steps. The mixing of naphthenic oil and carbon black avoids high shear heat generation caused by concentrated addition of carbon black, and further reduces carbon black aggregates to reduce steric hindrance. Therefore, in Example 5, a better dispersion compound can be obtained in step S1, allowing the GMF to better complete the crosslinking reaction in step S2. As a result, the medium resistance / aging resistance of the rubber products obtained in Example 5 can be further improved.

[0078] The above specific embodiments are only an explanation of the present application, which is not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A method for preparing high-temperature resistant and anti-aging butyl rubber, characterized in that, Includes the following steps: S1. Internal mixing: Set the initial temperature of the internal mixer to 50-60℃ and the rotation speed to 22-25 rpm; first, add butyl rubber and functional additives and premix for 1-2 minutes; then add carbon black premix and masticate for 1-2 minutes; subsequently, add stearic acid, zinc oxide, and antioxidant in sequence and mix and internally mix for 1-2 minutes; naphthenic oil is fed in slowly in two batches, with a total internal mixing time of 8-10 minutes. The discharge temperature is controlled below 100℃, and the mixture is cooled at room temperature after discharge. S2, Open Milling: Set the roller temperature of the open mill to ≤60℃, first plasticize 2-3 times, then add accelerator DM, p-quinone dioxime and lead oxide or manganese dioxide, turn the rubber to the left and right 3 times each; then pass through the thin mill 6-8 times and discharge the material, then let it stand at room temperature for 12 hours to obtain the compounded rubber sheet; S3. Vulcanization: Place the compounded rubber sheet from step S2 on a flat vulcanizing machine for vulcanization to obtain the target product. The vulcanization temperature is 150℃ and the vulcanization time is 15 min. In step S1, the naphthenic oil is added in two parts. The first part, 40-60 wt% of the total amount, is added 1-2 minutes after the carbon black premix is ​​added. The remaining part is added to the internal mixer after the stearic acid, zinc oxide, and antioxidant are added.

2. The method for preparing high-temperature resistant and anti-aging butyl rubber according to claim 1, characterized in that, In step S2, the initial rolling temperature is 45-55 ℃, and the surface temperature of the rubber compound is controlled below 75 ℃ during the thin-pass stage.

3. The method for preparing high-temperature resistant and anti-aging butyl rubber according to claim 1, characterized in that, In step S1, the mixing stage, the antioxidants include antioxidant RD and antioxidant 4010NA.

4. The method for preparing high-temperature resistant and anti-aging butyl rubber according to claim 1, characterized in that, In step S1, the first functional additive is a zinc soap of fatty acids, and the carbon black premix is ​​a mixture of carbon black and the second functional additive, which is nano-calcium carbonate; the average particle size of the nano-calcium carbonate is ≤50 nm.

5. The method for preparing high-temperature resistant and anti-aging butyl rubber according to claim 4, characterized in that, In step S1, when the carbon black in the carbon black premix is ​​50 wt% of the total amount of butyl rubber, the carbon black is added in two parts. The first part is 50 wt% of the total amount of carbon black added 1-2 minutes after the butyl rubber is added. This 50 wt% of carbon black is premixed with nano calcium carbonate to obtain the carbon black premix, and then fed into the internal mixer. The remaining carbon black and the naphthenic oil added in the first part are fed into the internal mixer together.

6. The method for preparing high-temperature resistant and anti-aging butyl rubber according to any one of claims 1-5, characterized in that, Includes the following steps, S1. Internal mixing: Set the initial temperature of the internal mixer to 50-60℃ and the rotation speed to 22-25 rpm; first, add 100 parts by weight of butyl rubber 1675 and 1 part by weight of fatty acid zinc soap for 1 min; then add 30 parts by weight of carbon black premix and plasticize for 2-3 min; then add 20 parts by weight of carbon black and 3 parts by weight of naphthenic oil and continue internal mixing for 2 min; then add 2 parts by weight of stearic acid, 5 parts by weight of zinc oxide and 2 parts by weight of antioxidant in sequence to the internal mixer and mix for 1 min; then add 3 parts by weight of naphthenic oil and continue internal mixing for 2-3 min. The total time for the internal mixing stage is 8-10 min. The discharge temperature is controlled below 100℃. After discharge, cool at room temperature. S2. Open mill: Set the roller temperature of the open mill to ≤60℃, first plasticize 2-3 times, then add 4 parts by weight of accelerator, 1.5 parts by weight of p-quinone dioxime, and 5 parts by weight of manganese dioxide, and turn the rubber to the left and right 3 times each; then pass through the thin mill 6-8 times and discharge the material, and then let it stand at room temperature for 12 hours to obtain the compounded rubber sheet. S3. Vulcanization: The compounded rubber sheet from step S2 is placed on a flat vulcanizing machine for vulcanization to obtain the target product. The vulcanization temperature is 150℃, the vulcanization pressure is 12MPa, and the vulcanization time is 15 min.

7. The method for preparing high-temperature resistant and anti-aging butyl rubber according to claim 6, characterized in that, When 30 parts by weight of carbon black premix are fed into the internal mixer in step S1, it is first plasticized in the internal mixer for 1 minute, then the top bolt of the internal mixer is lifted for cleaning, and then the mixing continues for 2 minutes.

8. The method for preparing high-temperature resistant and anti-aging butyl rubber according to claim 6, characterized in that, When adding naphthenic oil for the second time in step S1, first let all the mixture be internally mixed in the internal mixer for 1 minute, then lift the top bolt of the internal mixer to clean it, and then continue to internally mix for 30-60 seconds until the temperature reaches 100°C.

9. The method for preparing high-temperature resistant and anti-aging butyl rubber according to claim 6, characterized in that, In step S1, the carbon black is N330, and the carbon black premix is ​​prepared by premixing 30 parts by weight of carbon black N330 and 2 parts by weight of nano calcium oxide for 1 minute.

10. The method for preparing high-temperature resistant and anti-aging butyl rubber according to claim 6, characterized in that, The antioxidant in step S1 includes 1 part by weight of antioxidant RD and 1 part by weight of antioxidant 4010NA, and the accelerator in step S2 is accelerator DM.

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