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

Abstract

The application discloses a preparation method of high-temperature-resistant and anti-aging butyl rubber, which comprises the following steps: firstly, in a mixing stage at a lower temperature, raw rubber and carbon black are sequentially and step by step added, carbon black is coated by means of functional additives, the aggregation of carbon black is avoided, and the steric hindrance is reduced; then, part of naphthenic oil is added, stearic acid, zinc oxide, an antioxidant and the remaining part of naphthenic oil are added, multi-stage dispersion mixing is realized, and the temperature of discharging rubber is strictly controlled to be less than or equal to 100 DEG C; secondly, in a mixing stage at a low temperature, an accelerator DM, para-quinone dioxime and manganese dioxide are added, and the mixing rubber with uniform dispersion is obtained after thin passing multiple times and parking; and finally, the mixing rubber is vulcanized and formed on a flat plate. The coupling process of low temperature-step-by-step oil feeding-functional additive pre-dispersion is adopted, the rubber with the comprehensive performance of high-temperature resistance and anti-aging is obtained, the problems of the polar vulcanizing agent being wrapped by naphthenic oil and early scorching are avoided, and the traditional one-step mixing rubber is significantly superior; meanwhile, the process window is wide, and the energy consumption is low.

Description

Technical Field

[0001] This invention relates to the field of rubber materials technology, and specifically to a method for preparing high-temperature resistant and anti-aging butyl rubber. Background Technology

[0002] The limitations of traditional butyl rubber vulcanization systems: Butyl rubber (IIR), due to its highly saturated molecular chain, inherently possesses excellent airtightness and aging resistance, making it widely used in long-term heat- and media-resistant applications such as automotive inner tubes, pharmaceutical rubber stoppers, and chemical anti-corrosion linings. However, existing butyl formulations generally employ sulfur-accelerator systems (CZ / DM / TMTD, etc.) for vulcanization. This system generates primarily polysulfide bonds, which have the following drawbacks: Poor thermal stability: Polysulfide bonds have low bond energies and are prone to breakage-recombination reactions above 100°C, leading to decreased crosslinking density and increased compression set; High-temperature reversion tendency: After prolonged high-temperature service, the product surface is prone to becoming "sticky" or experiencing a sharp decrease in hardness; High gas permeability: Polysulfide segments are highly flexible and have a large free volume, making it difficult to meet the stringent requirements for ultra-low gas permeability in aerospace, aviation, and long-distance oil pipelines.

[0003] The exploration and bottlenecks of resin vulcanization systems: To overcome the shortcomings of sulfur systems, resin vulcanization technologies using phenolic resins, maleimide resins, or p-quinone dioxime (GMF) as vulcanizing agents have emerged in recent years. Their mechanism involves cross-linking through carbon-carbon bonds, ether bonds, or C=N bonds, resulting in 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 initiation temperature is high and the vulcanization induction period is long, making thick products prone to "core under-vulcanization"; Poor scorch safety: The resin system is prone to premature cross-linking during high-temperature mixing or extrusion, leading to difficult equipment cleaning and reduced yield; Lack of synergistic system: Although lead oxide can activate p-quinone dioxime, excessive dosage will increase the density of the rubber compound and increase environmental risks, and there is a lack of guidance on the synergistic ratio with the general-purpose accelerator DM.

[0004] With the rapid development of new energy hydrogen fuel cells, deep-sea oil and gas pipelines, and high-temperature chemical valve seals, the market has demanded that butyl rubber products meet requirements such as "continuous use at ≥120°C and gas permeability ≤2×10⁻⁶". -7 cm 3 ·cm / (cm 2 The comprehensive performance indicators are "compression set ≤20% (Pa·s·Pa)". However, existing sulfur systems or single resin systems are difficult to meet these requirements simultaneously. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a method for preparing high-temperature resistant and anti-aging butyl rubber.

[0006] This method uses a novel formulation with butyl rubber as the matrix and DM-p-quinone dioxime-lead oxide as the synergistic resin vulcanization system to obtain butyl rubber materials with high bond energy crosslinking network, low air permeability, and long-life sealing performance.

[0007] A high-temperature resistant and anti-aging butyl rubber composition, using 100 parts by weight of butyl rubber 1675 as the matrix, and incorporating the following components:

[0008] Carbon black N330 30–50 parts by weight;

[0009] Stearic acid 1.8–2.2 parts by weight;

[0010] Zinc oxide 4.5–5.5 parts by weight;

[0011] Antioxidant RD 1–1.5 parts by weight;

[0012] Antioxidant 4010NA 1–1.5 parts by weight;

[0013] Naphthenic oil 5.5–6.5 parts by weight;

[0014] Accelerator DM 0.8–4 parts by weight;

[0015] p-Quinone dioxime 1.2–1.5 parts by weight;

[0016] 1–5 parts by weight of lead oxide or manganese dioxide;

[0017] And optional functional additives, said functional additives comprising:

[0018] Zinc fatty acid soap, 0.8–1.2 parts by weight, and

[0019] Nano calcium carbonate, 1.5–2.5 parts by weight;

[0020] The average particle size of the nano-calcium carbonate is ≤50nm.

[0021] Furthermore, the amount of the accelerator DM is 3-4 parts by weight.

[0022] Furthermore, the amount of carbon black N330 used is 40-50 parts by weight.

[0023] A method for preparing high-temperature resistant and anti-aging butyl rubber includes the following steps:

[0024] 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.

[0025] 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;

[0026] 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.

[0027] 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.

[0028] Furthermore, in step S2, during the initial rolling stage, the initial rolling temperature is 45-55 ℃, and the surface temperature of the rubber compound is controlled below 75 ℃ during the thin-pass stage.

[0029] Furthermore, in the mixing stage of step S1, the antioxidants include antioxidant RD and antioxidant 4010NA.

[0030] Furthermore, in step S1, the first functional additive is a zinc soap of fatty acids, and the premix of 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.

[0031] Furthermore, in step S1, when the carbon black in the carbon black premix is ​​50 wt% of the total amount of butyl rubber added, 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.

[0032] The preparation method of high-temperature resistant and anti-aging butyl rubber involving specific formulations includes the following steps:

[0033] 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.

[0034] 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.

[0035] 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.

[0036] Furthermore, 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, and then the top bolt of the internal mixer is lifted for cleaning, and then the mixing continues for 2 minutes.

[0037] Furthermore, 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 plug of the internal mixer for cleaning, and then continue internal mixing for 30-60 seconds until the temperature reaches 100°C.

[0038] Furthermore, 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.

[0039] Furthermore, in step S1, the antioxidant includes 1 part by weight of antioxidant RD and 1 part by weight of antioxidant 4010NA, and in step S2, the accelerator is accelerator DM.

[0040] Compared to existing technologies, the beneficial effects of this preparation method on butyl rubber are as follows:

[0041] 1. Butyl rubber is a low-unsaturated rubber, and its vulcanization is much more difficult than that of NR and SBR. This invention uses accelerator DM, p-quinone dioxime, and lead oxide as vulcanizing agents. Its resin vulcanization system is mainly composed of high-energy carbon-carbon bonds and ether bonds, exhibiting high bond energy and good thermal stability, forming a stable cross-linked network. Compared to the polysulfide bonds in the sulfur vulcanization system, this significantly improves heat aging resistance and airtightness. This results in a more stable cross-linked structure and higher retention of physical properties under long-term high-temperature environments. Simultaneously, the dense network effectively blocks gas permeation, giving the product a longer service life and more reliable sealing performance.

[0042] 2. This method employs a low-temperature, low-speed, and stepwise premixing technique, with functional additives "pre-occupying" the space. Specifically, at an initial temperature of 50–60℃ and 25 rpm, zinc fatty acid soap and butyl rubber are added simultaneously, followed by the addition of nano-CaCO3 mixed with some carbon black. This allows the dispersant and spacer particles to form a synergistic coating layer around the carbon black, preventing ZnO and stearic acid from preemptively occupying the carbon black pores. This reduces the Payne effect and significantly improves the efficiency of subsequent quinone oxime crosslinking reactions, resulting in increased crosslinking density and excellent resistance to media in the rubber products.

[0043] 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.

[0044] 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.

[0045] 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

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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).

[0050] Antioxidants include any one or a combination of several of the following: 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), and 2-thiol-benzimidazole (antioxidant MB).

[0051] The carbon black is from the ASTM-N series, including N220, N330, etc.

[0052] The accelerator includes any one or a combination of several of N-cyclohexyl-2-benzothiazole sulfenamide (accelerator CZ), 2-thiol-benzothiazole (accelerator M), benzothiazole disulfide (accelerator DM), or tetramethylthiuram disulfide (accelerator TMTD).

[0053] The rubber performance testing method used in this invention is as follows:

[0054] Stress at constant elongation refers to the stress value that a material experiences or transmits when it is stretched to a fixed elongation ratio (strain) and kept constant during a tensile test. It describes "stress under a fixed elongation state".

[0055] Elongation at break refers to the percentage of relative elongation a material undergoes from its initial length to its fracture length during a tensile test. It is a key indicator characterizing the ductility (toughness / stretchability) of a material.

[0056] Hardness: The Shore hardness test was performed. The Shore hardness test method is GB / T531.1-2008 Test Method for Indentation Hardness of Vulcanized Rubber or Thermoplastic Rubber, Part 1.

[0057] Tensile strength: Measured according to GB / T528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber.

[0058] Media resistance test: Weigh the rubber sample to be tested and immerse it thoroughly in different solvents. Place the sample in an oven at a specific temperature according to the test requirements for 7 days. After immersion, remove the rubber sample, wash it with deionized water, and air dry it on filter paper (1-3 hours) or in an oven. Finally, weigh the sample and calculate the rate of change in mass.

[0059] Z = (M0 - M1) / M0 × 100%

[0060] Where M0 is the mass of the sample before immersion, and M1 is the mass of the sample after immersion.

[0061] 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).

[0062] Plasticity: The plasticity of rubber was determined using a plasticity testing machine (parallel plate method) according to GB / T 12828-2006 "Determination of plasticity and recovery value of raw rubber and unvulcanized compound rubber".

[0063] Plasticity P = (h 0- h1) / (h0+h1), h0: initial thickness, h1: height after compression.

[0064] Example 1

[0065] This embodiment uses butyl rubber as the base raw rubber to prepare a high-temperature resistant and anti-aging butyl rubber material. It includes the following components by weight: 100 parts butyl rubber 1675, 40 parts carbon black N330, 2 parts stearic acid, 5 parts zinc oxide, 1 part antioxidant RD, 1 part antioxidant 4010NA, 6 parts naphthenic oil, 0.8 parts accelerator DM (benzothiazole disulfide), 1.2 parts p-quinone dioxime, and 1 part lead oxide.

[0066] The process steps for preparing rubber from the above components are as follows:

[0067] 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 masterbatch and 50 parts by weight of carbon black 330 into the internal mixer and plasticize for 2-3 minutes. Then, 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 in sequence and continue mixing for 2-3 minutes. Finally, add 6 parts by weight of plasticizer naphthenic oil into the internal mixer and continue mixing for 3-5 minutes. Lift the top bolt of the internal mixer for cleaning, and continue mixing for 30-60 seconds until the temperature reaches 100℃ (mixing at 100℃ ensures sufficient dispersion but avoids scorching). Discharge the rubber to obtain rubber sheets, and cool them at room temperature after discharge.

[0068] S2. Open milling: Control the temperature of the open mill at 40-60℃ (to prevent premature vulcanization), and adjust the roll gap to 1.5mm. First, add the rubber sheet obtained in step S1 to the open mill for plasticizing 2-3 times (about 5-10 minutes). 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 three times each. Finally, adjust the roll gap of the open mill to 0.2mm and pass it through the mill 6-8 times before discharging. Let it stand at room temperature for 12 hours (to promote stress relaxation and migration of compounding agents) to obtain the compounded rubber.

[0069] S3. Vulcanization: The compounded rubber is vulcanized on a flat vulcanizing machine at 150°C for 15 minutes and a pressure of 12 MPa to obtain vulcanized rubber test pieces.

[0070] In the above steps, during the internal mixing stage of step S1, the butyl rubber masterbatch and carbon black are plasticized in an internal mixer at 50-60°C. The Mooney viscosity of butyl 1675 is approximately 45-55. At 50-60°C, the initial viscosity is sufficient to "powder" 40 parts of N330 in one go without clumping, that is, the shear force of the high-viscosity raw rubber is used to break up the carbon black aggregates. During this process, if the peak current drops by ≤10%, the power curve is stable, the rubber compound clumps together, and there is no visible carbon black dust on the surface, the dispersion can be confirmed to be ≥95%.

[0071] When the high-viscosity raw rubber mixture is coated onto the rotor, stearic acid, zinc oxide, and antioxidants are added sequentially. These smaller components disperse quickly. Stearic acid is added first to lubricate the rubber compound, reduce the peak internal temperature, and simultaneously "saponify" part of the carbon black surface, providing dispersion sites for zinc oxide. Zinc oxide follows, then Zn... 2 ⁺ It immediately forms soluble zinc soap with stearic acid, improving the dispersion speed; if ZnO is added first, due to its high surface polarity, it easily forms 2-5μm hard agglomerates, which are difficult to break up later. The antioxidant is added last. The amines in the antioxidant have low melting points, and adding them last can avoid being adsorbed by zinc oxide and reducing the effective concentration, and also reduce early volatilization.

[0072] The internal mixer temperature is initially set at 50-60℃. Due to rotor friction, the temperature rises by approximately 5℃ per minute. Therefore, after the first addition of rubber and carbon black and mixing for 2-3 minutes, the internal mixer temperature is between 75±5℃. After the second addition of stearic acid and other minor ingredients and mixing for 2-3 minutes, the temperature is between 90±5℃. After the third addition of naphthenic oil and further mixing for 3-5 minutes, the temperature is between 95-100℃. Once the oil is added, the system viscosity drops sharply. If the oil is added too early, the carbon black will form a soft outer and hard inner structure due to "oil-encapsulated carbon," resulting in decreased dispersibility. Adding naphthenic oil last among the minor ingredients utilizes the initial high shear to open up the carbon black structure, and then the oil is used to adjust viscosity, promote dispersion, and reduce heat generation. Because naphthenic oil has a large weight percentage and requires a longer mixing time, it is crucial to control the temperature during the naphthenic oil addition stage. Lowering the raw rubber temperature reduces heat generation and prevents minor components such as zinc oxide and antioxidants from reacting prematurely or clumping due to localized overheating. Simultaneously, it must be kept away from the critical decomposition temperature of quinone oxime vulcanizing agents (≈120℃) to prevent early scorching. The rubber is discharged at 100℃, at which point the carbon black is fully wetted, achieving a dispersion of over 95%, and the rubber surface is smooth. This temperature is still below the activation temperatures of accelerator DM and p-quinone dioxime (DM≈110℃, GMF≈120℃), ensuring no crosslinking occurs during the masterbatch stage.

[0073] With the above parameters, even after stirring for 4 minutes, the dispensing temperature can be stably controlled at 100±2℃, the risk of scorching remains unchanged, and the dispersion can still be maintained at over 95%.

[0074] In the initial mixing stage of step S2, the uniformly dispersed masterbatch sheet obtained in step (1) is fed into an open mill at 40-60℃. This is to ensure that the sheet can smoothly wrap around the rolls at a temperature above 40℃, preventing embrittlement and breakage. Below 60℃, it is necessary to ensure that the viscosity of the system is sufficiently high after adding the accelerator / vulcanizing agent. Firstly, the accelerators DM (melting point 154℃) and GMF (melting point 123℃) remain solid microcrystals at 40-60℃, but their particle size is typically ≤75μm. Secondly, at a thickness of 0.2 mm, the local shear rate at the roll gap is 10. 3 -10 4 s -1 The mechanical force generated is sufficient to further grind the particles (DM and GMF) to 1-3 μm and adhere them to the rubber chain, achieving micron-level dispersion of the solid phase.

[0075] To prevent premature reaction at low temperatures, the critical activation temperature of DM is approximately 110℃, and the crosslinking temperature of the GMF / lead oxide complex system begins around 120℃. If the roller temperature exceeds 80℃, the cumulative temperature rise during thin-pass processing can cause the rubber compound to locally reach 100–110℃, shortening the Mooney scorch t5 by more than 30% and resulting in "self-vulcanized" particles. Setting the temperature to 40-60℃ locks the upper limit of the discharge sheet temperature below 75℃, leaving a safety margin for subsequent storage, extrusion, or calendering. Scorching is prevented, and the complete crosslinking reaction is delayed until the final vulcanization stage at ≥150℃. Therefore, this temperature setting satisfies both process dispersion requirements and ensures processing safety.

[0076] Let it stand at room temperature for 12 hours to relax the molecular chains and reduce subsequent calendering / extrusion shrinkage; allow polar minor materials such as stearic acid and zinc oxide to continue migrating to the rubber-filler interface, improve interfacial bonding, and allow a small amount of residual air to diffuse out. The final temperature of the compound is ≤25℃ to avoid premature crosslinking.

[0077] Therefore, the process in this embodiment adopts the "oil first, sulfur later" sequence. First, high shear is used to thoroughly disperse carbon black and small materials, then oil is used to adjust the viscosity and cool the rubber compound. In the low-temperature open refining stage, accelerator, GMF and lead oxide are added respectively to ensure that each component is uniform and to avoid early scorching.

[0078] Example 2

[0079] This embodiment uses butyl rubber as the base raw rubber to prepare a high-temperature resistant and anti-aging butyl rubber material. It includes the following components by weight: 100 parts butyl rubber 1675, 30 parts carbon black N330, 2 parts stearic acid, 5 parts zinc oxide, 1 part antioxidant RD, 1 part antioxidant 4010NA, 6 parts naphthenic oil, 4 parts accelerator DM, 1.5 parts p-quinone dioxime, and 5 parts manganese dioxide.

[0080] The process steps for preparing rubber from the above components are as follows:

[0081] S1. Internal mixing: Set the initial temperature of the internal mixer to 50-60℃ and the rotation speed to 22-25 rpm. First, add the butyl rubber masterbatch and carbon black 330 into the internal mixer and plasticize for 2-3 minutes. Then, add the stearic acid, zinc oxide, and antioxidant in sequence into the internal mixer and continue mixing for 2-3 minutes. Finally, add the plasticizer naphthenic oil into the internal mixer and continue mixing for 3-5 minutes. Lift the top bolt of the internal mixer for cleaning, and continue mixing for 30-60 seconds until the temperature reaches 100℃ (mixing at 100℃ ensures sufficient dispersion but avoids scorching). Discharge the rubber to obtain rubber sheets, and cool them at room temperature after discharge.

[0082] S2. Open milling: Control the temperature of the open mill at 40-60℃ (to prevent premature vulcanization), and adjust the roll gap to 1.5mm. First, add the rubber sheet obtained in step S1 to the open mill for plasticizing 2-3 times (about 5-10 minutes). Then, add the accelerator, p-quinone dioxime, and manganese dioxide, and turn the rubber from left to right three times each. Finally, adjust the roll gap of the open mill to 0.2mm and pass it through the mill 6-8 times before discharging. Let it stand at room temperature for 12 hours (to promote stress relaxation and migration of compounding agents) to obtain the compounded rubber.

[0083] S3. Vulcanization: The compounded rubber is vulcanized on a flat vulcanizing machine at 150°C for 15 minutes and a pressure of 12 MPa to obtain vulcanized rubber test pieces.

[0084] Example 3

[0085] This embodiment uses butyl rubber as the base raw rubber to prepare a high-temperature resistant and anti-aging butyl rubber material. It includes the following components by weight: 100 parts butyl rubber 1675, 40 parts carbon black N330, 2 parts stearic acid, 5 parts zinc oxide, 1.5 parts antioxidant RD, 1.5 parts antioxidant 4010NA, 6 parts naphthenic oil, 4 parts accelerator DM, 1.5 parts p-quinone dioxime, 5 parts manganese dioxide, and functional additives, including 1 part of functional additive zinc fatty acid soap and 2 parts of functional additive nano-calcium carbonate (50nm).

[0086] The process steps for preparing rubber from the above components are as follows:

[0087] S1. Internal mixing: Set the initial temperature of the internal mixer to 50-60℃ and the rotation speed to 22-25 rpm. First, add the butyl rubber masterbatch and dispersant zinc fatty acid soap, and plasticize for 1 minute. Then, add the premix of carbon black 330 and nano calcium carbonate to the internal mixer and mix for 1 minute. Lift the top plug of the internal mixer to clean it, and continue mixing for 2 minutes. Add 3 parts of naphthenic oil and continue mixing for 2 minutes. Then, add stearic acid, zinc oxide, and antioxidant to the internal mixer in sequence, followed by the remaining 3 parts of naphthenic oil, and continue mixing for 2 minutes. Lift the top plug of the internal mixer to clean it, and continue mixing for 30-60 seconds until the temperature reaches 100℃ (mixing at 100℃ ensures sufficient dispersion but avoids scorching). Discharge the rubber to obtain the sheet, and cool it at room temperature after discharge.

[0088] S2. Open milling: Control the temperature of the open mill at 40-60℃ (to prevent premature vulcanization), and adjust the roll gap to 1.5mm. First, add the rubber sheet obtained in step S1 to the open mill for plasticizing 2-3 times (about 5-10 minutes). 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 three times each. Finally, adjust the roll gap of the open mill to 0.2mm and pass it through the mill 6-8 times before discharging. Let it stand at room temperature for 12 hours (to promote stress relaxation and migration of compounding agents) to obtain the compounded rubber.

[0089] S3. Vulcanization: The compounded rubber is vulcanized on a flat vulcanizing machine at 150°C for 15 minutes and a pressure of 12 MPa to obtain vulcanized rubber test pieces.

[0090] Example 4

[0091] This embodiment uses butyl rubber as the base raw rubber to prepare a high-temperature resistant and anti-aging butyl rubber material. It includes the following components by weight: 100 parts butyl rubber 1675, 50 parts carbon black N330, 2 parts stearic acid, 5 parts zinc oxide, 1.5 parts antioxidant RD, 1.5 parts antioxidant 4010NA, 6 parts naphthenic oil, 4 parts accelerator DM, 1.5 parts p-quinone dioxime, 5 parts manganese dioxide, and functional additives, including 1 part of functional additive zinc fatty acid soap and 2 parts of functional additive nano-calcium carbonate (50nm).

[0092] The process steps for preparing rubber from the above components are as follows:

[0093] S1. Internal mixing: Set the initial temperature of the internal mixer to 50-60℃ and the rotation speed to 22-25 rpm. First, add the butyl rubber masterbatch and dispersant zinc fatty acid soap, and masticate for 1 minute. Then, add carbon black 330 and nano calcium carbonate to the internal mixer and masticate for 1 minute. Lift the top plug of the internal mixer to clean it, and continue mixing for 2 minutes. Add 3 parts of naphthenic oil and continue mixing for 2 minutes. Then, add stearic acid, zinc oxide, and antioxidant to the internal mixer in sequence, followed by the remaining 3 parts of naphthenic oil, and continue mixing for 2 minutes. Lift the top plug of the internal mixer to clean it, and continue mixing for 30-60 seconds until the temperature reaches 100℃ (mixing at 100℃ ensures sufficient dispersion but avoids scorching). Discharge the rubber to obtain rubber sheets, and cool them at room temperature after discharge.

[0094] S2. Open milling: Control the temperature of the open mill at 40-60℃ (to prevent premature vulcanization), and adjust the roll gap to 1.5mm. First, add the rubber sheet obtained in step S1 to the open mill for plasticizing 2-3 times (about 5-10 minutes). 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 three times each. Finally, adjust the roll gap of the open mill to 0.2mm and pass it through the mill 6-8 times before discharging. Let it stand at room temperature for 12 hours (to promote stress relaxation and migration of compounding agents) to obtain the compounded rubber.

[0095] S3. Vulcanization: The compounded rubber is vulcanized on a flat vulcanizing machine at 150°C for 15 minutes and a pressure of 12 MPa to obtain vulcanized rubber test pieces.

[0096] Example 5

[0097] This embodiment uses butyl rubber as the base raw rubber to prepare a high-temperature resistant and anti-aging butyl rubber material. It includes the following components by weight: 100 parts butyl rubber 1675, 50 parts carbon black N330, 2 parts stearic acid, 5 parts zinc oxide, 1.5 parts antioxidant RD, 1.5 parts antioxidant 4010NA, 6 parts naphthenic oil, 4 parts accelerator DM, 1.5 parts p-quinone dioxime, 5 parts manganese dioxide, and functional additives, including 1 part of functional additive zinc fatty acid soap and 2 parts of functional additive nano-calcium carbonate (50nm).

[0098] The process steps for preparing rubber from the above components are as follows:

[0099] S1. Internal mixing: Set the initial temperature of the internal mixer to 50-60℃ and the rotation speed to 22-25 rpm. First, add the butyl rubber masterbatch and dispersant zinc fatty acid soap and premix for 1 minute. Then, add 30 parts of carbon black 330 and nano calcium carbonate to the internal mixer and masticate for 1 minute. Lift the top plug of the internal mixer to clean it, and continue mixing for 2 minutes. Add 20 parts of carbon black 330 and 3 parts of naphthenic oil, and continue mixing for 2 minutes. Then, add stearic acid, zinc oxide, and antioxidant to the internal mixer in sequence and mix for 1 minute. Then, add the remaining 3 parts of naphthenic oil and continue mixing for 1-2 minutes. Lift the top plug of the internal mixer to clean it, and continue mixing for 30-60 seconds until the temperature reaches 100℃ (mixing at 100℃ ensures sufficient dispersion but avoids scorching). Discharge the rubber to obtain a sheet, and cool it at room temperature after discharge.

[0100] S2. Open milling: Control the temperature of the open mill at 40-60℃ (to prevent premature vulcanization), and adjust the roll gap to 1.5mm. First, add the rubber sheet obtained in step S1 to the open mill for plasticizing 2-3 times (about 5-10 minutes). Then, add the accelerator, p-quinone dioxime, and manganese dioxide, and turn the rubber from left to right three times each. Finally, adjust the roll gap of the open mill to 0.2mm and pass it through the mill 6-8 times before discharging. Let it stand at room temperature for 12 hours (to promote stress relaxation and migration of compounding agents) to obtain the compounded rubber.

[0101] S3. Vulcanization: The compounded rubber is vulcanized on a flat vulcanizing machine at 150°C for 15 minutes and a pressure of 12 MPa to obtain vulcanized rubber test pieces.

[0102] Comparative Example 1

[0103] This embodiment uses butyl rubber as the base raw rubber and a sulfur accelerator system as the vulcanization system to prepare a high-temperature resistant and anti-aging butyl rubber material. It includes the following components by weight: 100 parts butyl rubber 1675, 30 parts carbon black N330, 2 parts stearic acid, 5 parts zinc oxide, 1 part antioxidant RD, 1 part antioxidant 4010NA, 6 parts naphthenic oil, 1 part accelerator DM, 0.3 parts accelerator TMTD, and 1 part sulfur.

[0104] The process steps for preparing rubber from the above components are as follows:

[0105] S1. Internal mixing: Set the initial temperature of the internal mixer to 45-55℃ (with 15℃ cooling water flowing through the rotor and chamber walls), and the speed to 15-18 rpm. First, add the butyl rubber masterbatch and carbon black 330 into the internal mixer and plasticize for 2 minutes. Then, add stearic acid, zinc oxide, and antioxidant in sequence to the internal mixer and continue mixing for 2-3 minutes. Finally, add the plasticizer naphthenic oil (approximately 20℃) to the internal mixer and continue mixing for 2-3 minutes. Lift the top bolt of the internal mixer for cleaning (open for 2 seconds to release pressure and heat), and continue mixing for 30-60 seconds until the temperature reaches approximately 80℃ (strictly control the temperature below 85℃). Discharge the rubber to obtain rubber sheets, and cool them at room temperature after discharge.

[0106] S2. Open milling: Control the temperature of the open mill at about 40℃ (to prevent premature vulcanization), and adjust the roller gap to 2mm. First, add the rubber sheet obtained in step S1 to the open mill for plasticizing once (about 2 minutes). Then, evenly sprinkle in DM + TMTD + sulfur pre-dispersed granules (complete within 1 minute), and turn the rubber to the left and right three times each. Finally, adjust the roller gap of the open mill to 0.5mm and pass it through the mill twice (total 2 minutes) before discharging. The rubber temperature should be ≤65℃ and the rubber sheet thickness should be 6mm. Cool the rubber to room temperature or ≤30℃ in air cooling for about 8 hours (to promote stress relaxation and compounding agent migration) to obtain the compounded rubber.

[0107] S3. Vulcanization: The compound rubber is vulcanized on a flat vulcanizing machine at 160°C for 15 minutes and a pressure of 102 MPa to obtain vulcanized rubber test pieces.

[0108] The performance test results of the above embodiments and comparative examples are shown in Table 1.

[0109] Table 1

[0110]

[0111] Comparing 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°C wider than that of the sulfur / TMTD / DM system in Comparative Example 1. The activation energy of the quinone dioxime / lead oxide system is higher, and significant crosslinking only occurs at ≥120°C; in actual production, 100°C can be set as the red line. The sulfur / super accelerator system in Comparative Example 1 is close to scorching at 75-80°C, and forced water cooling is necessary in summer. The quinone dioxime / lead oxide system can be stabilized by air cooling. There is no limit to the number of thin passes. For the quinone dioxime / lead oxide system, 6-8 thin passes of 0.2 mm and a cumulative temperature rise to 75°C still show no self-vulcanization. The sulfur / super accelerator system can only be mixed twice and rapidly sheeted to compare scorching. The quinone dioxime / lead oxide system offers high tolerance for storage time; the compound can be stored at 30°C for over 12 hours with a Mooney rise of less than 3%, while the sulfur-based super-accelerated system must be used within 8 hours, otherwise the Mooney rise will be 8-10%, resulting in "sesame seed spots" on the extruded surface. Overall, the quinone dioxime / lead oxide system can achieve high-temperature performance using a room-temperature processing method, while the sulfur-based super-accelerated system requires low-temperature, high-speed processing throughout, significantly increasing equipment investment, energy consumption, process cycle time, and the risk of scrap. Therefore, the quinone dioxime route has a significant advantage in high-end heat-resistant butyl products.

[0112] Furthermore, as shown in Table 1, the tensile strength of the rubber product obtained in Example 1 is superior to that in Comparative Example 1, and its resistance to media is further improved. This is because the quinone dioxime / lead oxide system forms high-energy carbon-carbon bonds and ether bonds, resulting in thermal stability far exceeding that of the polysulfide bonds in the sulfur-accelerated system. Therefore, it is less prone to bond breakage, recombination (re-sulfurization), or degradation at high temperatures. Through the synergistic activation of accelerator DM and lead oxide, the vulcanization reaction is more gradual, the induction period is extended, and the risk of "core under-sulfurization" in thick products is reduced. Once the resin crosslinking network is formed, it is not easily degraded (over-sulfurized) due to prolonged vulcanization time, resulting in a high retention rate of physical properties.

[0113] In Example 2, the amount of accelerator DM and the oxidant manganese dioxide were adjusted in the quinone dioxime / lead oxide system. Compared with lead oxide, manganese dioxide has a higher redox potential, which improves the conversion rate of GMF to p-nitrosobenzene. Since the amount of carbon black was reduced, the steric hindrance at the rubber chain ends was reduced during rubber premixing, making it easier for the free radicals of p-nitrosobenzene to approach the double bonds in the rubber molecules and form a C–N–C network structure more quickly. Therefore, after adjusting the quinone dioxime / lead oxide system, although the amount of carbon black was reduced, the performance of the rubber product did not decrease. This proves that the preparation method of Example 2 can obtain rubber products with excellent performance in quinone dioxime systems with different accelerator ranges.

[0114] In Examples 3 to 5, functional composite additives (1 part of zinc fatty acid soap and 2 parts of 50nm CaCO3) were added to the overall formulation. Although the carbon black was increased to 40 parts, the zinc fatty acid soap was pre-mixed with the raw gum, and the nano CaCO3, as spacer particles, could preemptively adsorb or penetrate to the carbon black surface, reducing the formation of carbon black aggregates and significantly improving dispersion efficiency. The zinc fatty acid soap, as a lipophilic molecule, was added first, and the surface of the nano CaCO3 was treated with fatty acids. When the two coexisted, they could form a synergistic coating layer that wrapped around the outer layer of carbon black, preventing the carbon black surface vacancies from being occupied by stearic acid or zinc oxide, thus weakening the dispersion effect. When the carbon black content is further increased to 50 parts, it can be added in two steps. First, carbon black and nano-CaCO3 are mixed and kneaded to obtain carbon black particles with a synergistic coating. Then, carbon black and a portion of naphthenic oil are added. The purpose of this second step is to add the naphthenic oil before stearic acid, ZnO, and antioxidants. The high permeability of the oil helps to expand the carbon black aggregates, fill the internal voids, reduce aggregate strength, and ensure the oil film is present on the surface of the synergistic coating. This reduces the adsorption of subsequent inorganic powders, lubricates the carbon black-rubber interface during the strongest shear phase, and lowers the interfacial energy. This multiple approach significantly reduces the steric hindrance around the double bonds in the rubber molecules. The final addition of naphthenic oil is after stearic acid, ZnO, and antioxidants. This reduces shear heat generation at the end of the kneading process, controlling the discharge temperature at 100℃.

[0115] Compared to Example 2, when stearic acid, ZnO, and antioxidant were added first, followed by oil, the steric hindrance around the double bonds in the rubber molecules did not decrease further due to insufficient reduction in carbon black aggregates. This made it difficult for GMF free radicals to approach the double bonds in the rubber molecules during the subsequent open milling stage. On the other hand, the small-sized and highly polar zinc oxide and stearic acid preferentially entered the carbon black voids, forming shell-core hard clusters. When the naphthenic oil was added later, it could not penetrate fully. Therefore, Examples 3 and 4 adopted the stepwise addition of naphthenic oil and the addition of functional composite additives for the pretreatment of carbon black mixing. The rubber products prepared in this way have better resistance to media and aging than those in Examples 2 and 1. When a large amount of carbon black is added in stages in Example 5, the carbon black is added in two steps. By mixing the naphthenic oil and carbon black, on the one hand, the high shear caused by the concentrated addition of a large amount of carbon black is avoided, and on the other hand, the carbon black aggregates are further reduced, thereby reducing steric hindrance. Therefore, in the rubber preparation process of Example 5, a better dispersed rubber compound can be obtained in step S1, so that GMF can better complete the crosslinking reaction in the initial kneading stage of step S2. Therefore, the rubber products obtained in Example 5 have further improved resistance to media and aging resistance.

[0116] The above specific embodiments are merely explanations of this application and are not intended to limit this application. After reading this specification, those skilled in the art can make modifications to these embodiments without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

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 DM, 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, In step S1, when 30 parts by weight of carbon black premix are fed into the internal mixer, it is first plasticized in the internal mixer for 1 minute, and 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 plug of the internal mixer for cleaning, and continue internal mixing 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.

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