A high-efficiency low-temperature vulcanization preparation method of acid and alkali resistant rubber pad

Abstract

The application discloses a high-efficiency low-temperature vulcanization preparation method of an acid-alkali-resistant rubber pad, and comprises the following steps: S1, preparing materials according to precise proportioning of a raw material system; wherein, the raw material system comprises, in terms of weight parts, 100 parts of acid-alkali-resistant base rubber, 4-7 parts of an activation system, 35-60 parts of reinforcing barrier fillers, 8-16 parts of acid-alkali-resistant in-situ compounded modification additives, 1.8-3.6 parts of a low-temperature rapid composite vulcanization system, 2-5 parts of processing lubricating additives and 1.2-2.8 parts of anti-aging stabilizers; S2, segmental constant-temperature plasticizing; S3, in-situ compounding of acid-alkali-resistant modifiers based on the acid-alkali-resistant in-situ compounded modification additives; S4, secondary finalizing of the low-temperature vulcanization system; S5, standing and curing of the rubber compound; S6, low-temperature rapid mold pressing vulcanization forming based on the low-temperature rapid composite vulcanization system; and S7, normal-temperature normal-pressure stable post-processing.

Description

Technical Field

[0001] This invention belongs to the technical field of rubber and plastic anti-corrosion material manufacturing process, specifically relating to an efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads. Background Technology

[0002] Acid and alkali resistant rubber mats are widely used in industrial settings such as chemical, electroplating, metallurgy, wastewater treatment, and pharmaceutical industries where strong acids and alkalis come into contact with the environment. They rely on the stable molecular structure of the rubber matrix and the barrier fillers to form a dense protective layer, preventing the penetration of acid and alkali media and providing sealing, buffering, and corrosion protection. Currently, the domestic industrial production of acid and alkali resistant rubber mats still generally adopts the traditional high-temperature vulcanization process, with the mainstream vulcanization temperature range of 150–165℃ and the standard vulcanization holding time of 25–40 minutes. This entire production process has many inherent defects, and existing modification and vulcanization technologies in the industry face a technical contradiction in achieving a balance between energy saving, efficiency, and corrosion resistance.

[0003] First, traditional high-temperature vulcanization processes are energy-intensive and generate significant carbon emissions, failing to meet current energy-saving renovation policies for the rubber and plastics manufacturing industry. Traditional flat vulcanizing machines maintain temperatures above 150°C for extended periods, with molds and hot plates continuously supplied with high-power heat. Heat loss during the heating and insulation stages of a single batch of rubber pads is substantial. The long vulcanization cycle results in low output per unit time, and the equipment operates under idle heating conditions for a high proportion of the time. The comprehensive electricity consumption per ton of finished rubber pads typically reaches 280–350 kWh. Simultaneously, the high-temperature environment easily causes the volatilization of small-molecule additives in the rubber system, generating trace amounts of organic waste gas. This necessitates high-power waste gas treatment equipment, further increasing equipment investment and operating energy consumption, resulting in insufficient environmental friendliness in the overall manufacturing process. Existing industry energy-saving renovation solutions mostly focus on optimizing equipment such as vulcanizing machine insulation layers and waste heat recovery, without addressing the vulcanization system formulation and reaction mechanism to reduce the basic vulcanization temperature. Therefore, the energy-saving effect is limited, only reducing comprehensive energy consumption by 8%–15%, resulting in low renovation benefits.

[0004] Secondly, the long vulcanization cycle at high temperatures limits production line capacity and increases production costs. Traditional vulcanization processes take at least 25 minutes, with a single vulcanizing machine producing only about 30 batches per day. Facing large orders for anti-corrosion gaskets from the chemical industry requires additional vulcanization equipment and expanded factory buildings, leading to a simultaneous increase in fixed asset investment and labor costs. Some companies have attempted to increase vulcanization temperature to shorten vulcanization time, but temperatures exceeding 160℃ easily result in localized scorching of the rubber compound, surface cracking of the rubber gaskets, and internal microporous defects, increasing product scrap rates. Furthermore, high temperatures accelerate the thermal degradation of rubber molecular chains, causing irreversible decline in the tensile strength and acid / alkali resistance of the finished product, making it impossible to balance production efficiency and product quality.

[0005] Third, conventional acid and alkali resistant rubber modification processes involve stepwise addition of fillers to the vulcanization system, resulting in uneven filler dispersion and limited improvement in corrosion resistance. In existing acid and alkali resistant rubber preparation processes, corrosion-resistant fillers and modifying agents are simply physically blended with raw rubber without in-situ interface modification of the filler surface. Barium sulfate, montmorillonite, and other barrier fillers easily agglomerate in the rubber matrix, forming micron-sized particle clusters. Acid and alkali media can rapidly penetrate along the gaps in these agglomerates. After long-term immersion in acid and alkali media, the volume swelling rate of the rubber pad can reach 12%–18%, and bulging and delamination failure occur after 3–6 months of continuous use. Increasing the amount of corrosion-resistant filler alone directly reduces the rubber's elasticity and tensile mechanical strength, significantly decreasing the pad's pressure-bearing and cushioning performance, making it unsuitable for equipment vibration damping and sealing conditions. Existing in-situ modification technologies are mostly applied to high-end fluororubber products, resulting in high raw material costs and making large-scale application to general-purpose acid and alkali resistant industrial pads difficult. Furthermore, the modification process has poor compatibility with the vulcanization system, and cross-linking is incomplete at low temperatures.

[0006] Fourth, existing low-temperature vulcanization rubber technology has significant shortcomings and cannot be simultaneously adapted to the production of acid and alkali resistant and corrosion-resistant products. Most publicly available low-temperature vulcanization rubber formulations are designed for sealing rings and everyday rubber parts, focusing solely on low-temperature molding without a dedicated acid and alkali resistant modification system. Simply relying on accelerators to lower the vulcanization temperature results in insufficient cross-linking density, increased free volume within the rubber, and easier diffusion of small acid and alkali molecules into the matrix, leading to substandard corrosion resistance. Some low-temperature vulcanization systems use peroxide cross-linking, which has higher raw material costs than sulfur vulcanization systems, and decomposition byproducts can damage the rubber's barrier structure, exacerbating acid and alkali swelling. Furthermore, the existing low-temperature vulcanization process lacks optimized mixing, curing, and post-processing steps, resulting in poor processing stability of low-temperature vulcanized rubber compounds, large fluctuations in product performance during mass production, and a low yield rate.

[0007] In summary, the current acid and alkali resistant rubber mat manufacturing industry lacks a process solution that optimizes the entire process from raw material compounding, mixing and processing, low-temperature vulcanization molding to post-processing. It is impossible to simultaneously achieve the five goals of reducing vulcanization temperature, shortening molding cycle, reducing production energy consumption, improving acid and alkali corrosion resistance, and improving mechanical strength. Traditional high-temperature vulcanization processes have high energy consumption, low production efficiency, and large waste gas emissions, and there is a lot of room for process transformation. They are traditional rubber and plastic manufacturing processes that urgently need energy-saving and environmental protection upgrades. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies in the aforementioned industries by developing an integrated preparation process that combines a low-temperature rapid vulcanization system with an acid and alkali resistant modifier in situ. This process does not modify existing vulcanization equipment; instead, it achieves energy-saving and efficiency-enhancing upgrades to traditional anti-corrosion rubber gasket production lines through formula optimization and refined control of process steps. This invention provides a low-temperature rapid vulcanization preparation process for acid and alkali resistant rubber gaskets, designed for industrial anti-corrosion applications while also considering energy conservation and environmental protection. The product is suitable for the production of industrial anti-corrosion gaskets such as chemical storage tank liners, pickling tank sealing gaskets, anti-corrosion pads for electroplating equipment, and buffer rubber gaskets for acid and alkali pools in wastewater treatment. It represents an energy-saving and consumption-reducing improvement technology for traditional rubber hot vulcanization manufacturing processes.

[0009] The purpose of this invention is to provide an efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads, comprising:

[0010] S1. Prepare materials according to the precise proportions of the raw material system; wherein, by weight, the raw material system comprises: 100 parts of acid and alkali resistant base raw rubber, 4-7 parts of activation system, 35-60 parts of reinforcing and barrier filler, 8-16 parts of acid and alkali resistant in-situ compounding and modifying agent, 1.8-3.6 parts of low-temperature rapid composite vulcanization system, 2-5 parts of processing and lubricating agent, and 1.2-2.8 parts of anti-aging stabilizer; wherein, the acid and alkali resistant in-situ compounding and modifying agent comprises silane-modified nano-barium sulfate, epoxy-modified montmorillonite, and maleic anhydride-grafted polyene. The three hydrocarbons are in-situ blended powders; wherein the low-temperature rapid composite vulcanization system is composed of low-temperature accelerator A, low-temperature accelerator B, and slow-release sulfur in a mass ratio of 1:0.6-0.9:1.2-1.6; the vulcanization temperature of the low-temperature rapid molding vulcanization is controlled at 125-138℃, the vulcanization holding time is 8-18 min, and the molding pressure is 10-14 MPa; wherein the low-temperature accelerator A is dibenzothiazole disulfide MBT, and the low-temperature accelerator B is N-cyclohexyl-2-benzothiazole sulfenamide CBS;

[0011] S2, segmented constant temperature plasticizing;

[0012] S3, based on the acid and alkali resistant in-situ compounding and modifying agent, perform a first-stage intensive mixing of the acid and alkali resistant modifier in-situ compounding agent;

[0013] S4, low-temperature vulcanization system, secondary final refining;

[0014] S5, rubber compound is left to mature under static conditions;

[0015] S6, Low-temperature rapid compression molding is performed based on the aforementioned low-temperature rapid composite vulcanization system;

[0016] S7, post-processing for stabilization at room temperature and pressure.

[0017] Preferably, the matrix raw rubber is any one or a blend of two of chloroprene rubber CR1212, nitrile rubber NBR3305, and ethylene propylene diene monomer rubber EPDM4045; the activation system is a compound of indirect zinc oxide and stearic acid in a mass ratio of 3.2 to 4.5:1; and the reinforcing and barrier filler is a compound of precipitated silica, barite powder, and calcined kaolin in a mass ratio of 2:1.1:0.8.

[0018] Preferably, the anti-aging stabilizer is a mixture of 4010NA antioxidant and microcrystalline wax at a ratio of 1:0.5; the processing lubricant is a mixture of naphthenic rubber processing oil and polyethylene wax at a mass ratio of 2.5:1.

[0019] Preferably, S1 includes:

[0020] S11, Weigh all solid powder additives, granular raw rubber and liquid processing aids according to the formula weight parts of the raw material system; wherein, the weighing error of all raw materials is controlled to be ≤±0.3wt%; the raw materials are stored in separate areas, and the vulcanization system is stored separately in a sealed and light-proof manner to avoid premature pre-crosslinking;

[0021] S12, the granular raw rubber is pre-cut into 5-10cm rubber blocks, and the solid powder additive is sieved through a 120-mesh standard sieve to remove agglomerates; the liquid processing additive is quantitatively delivered using a constant temperature metering pump.

[0022] Preferably, S2 includes:

[0023] S21, the cut rubber blocks are fed into a two-roll mill for two-stage plasticizing; the first stage plasticizing has a roll temperature of 45-55℃, a roll gap of 3.0-4.0mm, a plasticizing time of 3-5min, and the rubber compound is passed through the mill 4 times after completely covering the rolls; the second stage plasticizing has a roll temperature of 60-70℃, a roll gap of 1.0-1.8mm, and is passed through the mill 6-8 times.

[0024] S22, Quality control of the raw rubber plasticizing process is based on the plasticizing endpoint condition parameters; wherein, the plasticizing endpoint condition parameters are to control the Mooney viscosity ML(1+4) at 100℃ to be 48-56; this parameter is the core quality control indicator of the raw rubber plasticizing process, and the Mooney viscosity ML(1+4) at 100℃ characterizes the shear flowability and molecular chain breakage degree of the rubber compound at 100℃. In this invention, the segmented plasticizing process limits the viscosity to the range of 48-56. A viscosity higher than 56 indicates that the raw rubber molecular chains are too long and the rubber compound is too rigid, making it difficult to evenly disperse modified fillers and low-temperature vulcanization aids during subsequent internal mixing, which can easily lead to filler agglomeration, incomplete interfacial grafting, and reduced acid and alkali resistance; a viscosity lower than 48 indicates excessive degradation of molecular chains, a significant decrease in the basic mechanical strength of the rubber matrix, and a decrease in the tensile and tear strength of the finished product. This range can balance the processing flowability of the rubber compound and the inherent strength of the matrix, ensuring that the in-situ modification reaction is fully carried out in the first stage of internal mixing, while avoiding problems such as the rubber compound being too soft and sticking to the mold, and fluctuations in molding dimensions during the final mixing and low-temperature vulcanization stages.

[0025] S23, based on meeting quality control requirements, is sheeted out after plasticizing and cooled to room temperature for later use.

[0026] Preferably, S3 includes:

[0027] S31, the plasticized raw rubber is fed into a closed internal mixer, wherein the initial temperature of the mixing chamber of the closed internal mixer is 70-80℃ and the rotor speed is 35-45rpm.

[0028] S32 is added sequentially to the activation system, processing lubricant and anti-aging stabilizer, and mixed for 1.5 to 2.5 minutes;

[0029] S33, reinforcing and barrier fillers and acid and alkali resistant in-situ compounding modifiers are added in two batches. After each batch is added, the mixture is mixed for 2 minutes. The maximum temperature of the mixing chamber of the closed mixer is controlled to not exceed 118℃ throughout the process. After the material reaches the preset temperature, the top plug is raised to discharge the rubber, and a section of mixed rubber is obtained.

[0030] Preferably, S4 includes:

[0031] S41, the section of compounded rubber is fed into the roll wrapper of a two-roll mill, with a roll temperature of 55-65°C;

[0032] S42 is slowly and evenly added to the low-temperature rapid compound vulcanization system, and the mixture is turned over by the left and right cutters at least 8 times, with a total turning time of 2.5 to 4 minutes; the surface temperature of the rubber compound should not exceed 92°C throughout the final mixing process to prevent the risk of scorching.

[0033] S43, after final refining, produces uniformly 2.2-2.8mm thick rubber sheets without localized white spots caused by vulcanizing agent aggregation.

[0034] Preferably, S5 includes:

[0035] S51, after the final refining is completed, the film is laid flat on a clean and ventilated material rack, stacked in a single layer, with anti-stick paper separating the film sheets;

[0036] S52, set the ambient temperature to 22~28℃, the relative humidity to 40%~60%, and let it stand in the dark for 16~24h to obtain the cured film; the curing process completes the diffusion of additive molecules and the secondary bonding at the filler interface, eliminates the internal stress of the mixing, and the hardness fluctuation range of the cured film is ≤±2HA.

[0037] Preferably, S6 includes:

[0038] S61, the cured film is cut to match the size of the rubber pad mold cavity, and the film filling amount exceeds the cavity volume by 5% to 8%;

[0039] S62, preheat the mold to 125-138℃, and apply a constant pressure of 10-14MPa after closing the mold;

[0040] S63, low temperature holding pressure vulcanization for 8-18 minutes, after vulcanization, quickly open the mold and demold. After demolding, the rubber pad naturally detaches from the mold, without sticking, missing material and air bubbles; the temperature fluctuation of the mold is controlled ≤±2℃.

[0041] Preferably, S7 includes:

[0042] S71, after demolding, lay the rubber pad flat on a ventilated workbench and let it rest naturally at room temperature (20-30℃) for 4-6 hours to release the internal stress of vulcanization.

[0043] S72, trim the edge burrs and polish the parting surface;

[0044] S73, after completing the initial inspection of size and appearance, is placed in a ventilated storage environment and left to stand for 72 hours to eliminate residual small molecule volatiles from sulfurization, finally obtaining the finished acid and alkali resistant rubber pad.

[0045] The beneficial effects of the preparation method of the present invention:

[0046] 1. Significantly reduced production energy consumption and outstanding energy-saving and environmental protection benefits: The vulcanization temperature is reduced by 20-40℃, the molding cycle is shortened by more than 40%, the comprehensive electricity saving per ton of finished product is 30%-45%, the amount of volatile organic waste gas is reduced by 70%, reducing the energy consumption for waste gas treatment and pollutant emissions, which meets the requirements of energy conservation, carbon reduction and clean production in the rubber and plastics industry.

[0047] 2. Production efficiency is greatly improved and manufacturing costs are reduced: the number of batches formed per day by a single flat vulcanizing machine is increased from 30 to 48-52, which can reduce the investment in vulcanizing equipment by 25% under the same capacity demand; vulcanizing energy consumption, equipment depreciation and labor hours are reduced simultaneously, and the comprehensive manufacturing cost per ton of rubber pads is reduced by 12%-19%.

[0048] 3. Significantly improved acid and alkali resistance and corrosion protection: After being immersed in 30wt% sulfuric acid and 30wt% sodium hydroxide solution at room temperature for 720 hours, the volume swelling rate of the finished rubber pad is ≤4.8% and the weight change rate is ≤3.2%, with no bulging, delamination, or surface powdering. Under the same conditions, the swelling rate of the traditional high-temperature vulcanization control sample is 14.6%, the weight loss is 8.3%, and local bulging failure occurs after 180 hours.

[0049] 4. Simultaneous optimization of mechanical properties: The finished product of this invention has a tensile strength ≥16.2MPa and a tear strength ≥48kN / m; the sample with the same filler ratio in the traditional process has a tensile strength of 12.8MPa and a tear strength of 37kN / m, which improves the mechanical properties by more than 18%, and extends the pressure bearing capacity, wear resistance and service life of the rubber pad.

[0050] 5. Strong stability in industrial mass production and simple to implement: The whole process is compatible with existing general rubber processing equipment without the need for new large-scale equipment; the process parameters have a wide range, and the tolerance for errors in raw material weighing, temperature and time control is high. The fluctuation range of hardness, swelling and strength indicators between batches of mass production is ≤±5%, and the yield rate is stable at ≥98.5%, which is suitable for large-scale continuous production of chemical anti-corrosion rubber mats. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of the present invention, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0052] Figure 1 This is a flowchart illustrating the efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads according to an embodiment of the present invention. Detailed Implementation

[0053] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0055] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0056] The embodiments of this invention overcome the multiple defects of existing high-temperature vulcanization processes for acid and alkali resistant rubber pads, such as high energy consumption, long vulcanization cycles, poor acid and alkali swelling resistance, and insufficient mechanical strength. It also solves the industry problem that existing low-temperature vulcanization technologies cannot simultaneously achieve both corrosion resistance and mass production stability. This invention provides a highly efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads. Based on a low-temperature rapid composite vulcanization system, it reduces the activation energy of the vulcanization reaction. Combined with an in-situ compounding and mixing process for acid and alkali resistant modifiers, it optimizes the interface bonding of fillers. While reducing vulcanization temperature, shortening the molding cycle, and reducing production energy consumption, it simultaneously improves the rubber pad's resistance to acid and alkali corrosion and its tensile and tear mechanical strength. This achieves energy-saving and environmentally friendly transformation of traditional rubber manufacturing processes, making it suitable for the stable mass production of large-scale industrial anti-corrosion rubber pads in chemical, electroplating, and wastewater treatment industries.

[0057] like Figure 1 As shown, an embodiment of the present invention provides a highly efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads, comprising:

[0058] S1, precise proportioning and preparation of raw materials;

[0059] S2, segmented constant temperature plasticizing;

[0060] S3, acid and alkali resistant modifier in situ compounded and mixed in one stage;

[0061] S4, low-temperature vulcanization system, secondary final refining;

[0062] S5, rubber compound is left to mature under static conditions;

[0063] S6, low-temperature rapid compression molding and vulcanization;

[0064] S7, stable post-treatment at room temperature and pressure;

[0065] Each process is equipped with a dedicated raw material compounding system, including two technical modules: a low-temperature rapid compound vulcanization system and an integrated mixing technology for in-situ compounding of acid and alkali resistant modifiers.

[0066] The raw material system is uniformly proportioned by weight as follows: 100 parts of acid and alkali resistant base raw rubber, 4-7 parts of activation system, 35-60 parts of reinforcing and barrier filler, 8-16 parts of acid and alkali resistant in-situ compound modification agent, 1.8-3.6 parts of low temperature rapid composite vulcanization system, 2-5 parts of processing lubricant, and 1.2-2.8 parts of anti-aging stabilizer.

[0067] The core raw material components include:

[0068] (1) Low-temperature rapid composite vulcanization system: Low-temperature accelerator A (MBT), low-temperature accelerator B (CBS), and slow-release sulfur are compounded in a mass ratio of 1:0.6-0.9:1.2-1.6; the two accelerators work together to reduce the activation energy of the vulcanization reaction, so that the vulcanization crosslinking reaction can be fully completed in the range of 125-138℃. The slow-release sulfur slowly releases crosslinking active sulfur molecules, avoiding insufficient crosslinking density at low temperature, and at the same time eliminating high-temperature scorching defects.

[0069] (2) Acid and alkali resistant in-situ compounding modification additives: silane-modified nano barium sulfate, epoxy-modified montmorillonite, and maleic anhydride-grafted polyolefin are mixed in-situ in powder form. During the in-situ blending process, epoxy groups and silane hydroxyl groups react with rubber molecular chains and filler surface hydroxyl groups simultaneously to form a continuous and dense barrier network, which greatly reduces the penetration rate of acid and alkali media, and simultaneously improves the bonding force between filler and rubber matrix, taking into account both anti-corrosion performance and mechanical properties.

[0070] (3) The base raw rubber is selected from chloroprene rubber, nitrile rubber and EPDM rubber, either alone or in blends. The cost of these three types of general-purpose rubber raw materials is moderate, and their basic acid and alkali resistance is better than that of natural rubber, making them suitable for most industrial anti-corrosion conditions. The activation system is an indirect zinc oxide + stearic acid compound, which provides stable activation sites for low-temperature vulcanization. The reinforcing barrier filler is a ternary compound of silica, barite and calcined kaolin, with multiple layers and particle structures superimposed to form physical barrier channels, inhibiting acid and alkali diffusion. The processing lubricant is naphthenic oil + polyethylene wax, which improves the fluidity of the low-temperature rubber compound and reduces the resistance of mixing and molding. The anti-aging stabilizer is an amine antioxidant + microcrystalline wax compound, which reduces the volatilization of small molecules during vulcanization and improves the long-term resistance of the rubber pad to media aging.

[0071] Process parameter control includes:

[0072] (1) The temperature of the vulcanization molding process is reduced to 125-138℃, which significantly reduces the heat energy consumption compared to the traditional high-temperature vulcanization of 150-165℃;

[0073] (2) The vulcanization holding time is reduced to 8-18 minutes, the molding cycle is shortened by 40%-65%, and the daily production capacity of a single machine is increased by more than 50%;

[0074] (3) The maximum temperature during the entire mixing process shall not exceed 118℃, and the temperature of the final compound shall be controlled below 92℃. The vulcanization system shall not undergo pre-crosslinking in advance, and the storage and curing stability of the compound shall be greatly improved.

[0075] (4) The entire process of segmented plasticizing, in-situ compounding and internal mixing, low-temperature final mixing, light-proof curing and room-temperature post-treatment is coordinated and controlled to ensure the consistency of low-temperature vulcanized rubber processing and the mass production yield is stable at over 98.5%.

[0076] Raw material specifications for application examples (the application examples use standardized raw material specifications and are commercially available industrial raw materials).

[0077] (1) Base rubber: CR1212 chloroprene rubber, NBR3305 nitrile rubber, EPDM4045 ethylene propylene diene monomer rubber;

[0078] (2) Activation system: indirect zinc oxide (325 mesh), industrial stearic acid;

[0079] (3) Reinforcing and barrier fillers: precipitated silica (150nm), 400 mesh barite powder, calcined kaolin;

[0080] (4) Acid and alkali resistant in-situ compounding modification additives: silane modified nano barium sulfate (80nm), epoxy intercalated montmorillonite, and MAH grafted EVA powder are premixed into finished products.

[0081] (5) Low-temperature composite vulcanization system: MBT (accelerator A), CBS (accelerator B), slow-release coated sulfur;

[0082] (6) Processing lubricants: naphthenic rubber processing oil (flash point 290℃), polyethylene wax;

[0083] (7) Anti-aging stabilizers: Anti-aging agent 4010NA, industrial microcrystalline wax.

[0084] Application Example 1: Application scenario: 5mm thick acid and alkali resistant neoprene rubber pads for chemical pickling tanks.

[0085] 1. Raw material weight ratio

[0086] 100 parts of chloroprene rubber CR1212; 5.2 parts of activation system (4.2 parts of zinc oxide + 1 part of stearic acid); 40 parts of reinforcing and barrier filler (20 parts of silica + 11 parts of barite + 9 parts of kaolin); 12 parts of acid and alkali resistant in-situ compound modification additive; 2.7 parts of low-temperature rapid composite vulcanization system (0.9 parts of MBT, 0.7 parts of CBS, 1.1 parts of slow-release sulfur, mass ratio 1:0.78:1.22); 3 parts of processing lubricant (2 parts of naphthenic oil + 1 part of polyethylene wax); 1.8 parts of anti-aging stabilizer (1 part of 4010NA + 0.8 parts of paraffin wax).

[0087] 2. Stepwise preparation process

[0088] S1, Precise raw material proportioning and preparation: Weigh 100kg of CR1212 rubber blocks and cut them into 6cm blocks; all powdered additives are filtered through a 120-mesh sieve, and liquid naphthenic oil is added quantitatively using a metering pump; the weighing error of all materials is controlled within ±0.2%; the low-temperature vulcanization system is stored separately in a sealed, light-proof environment, and is separated from other materials.

[0089] S2, segmented constant temperature plasticizing: two-roll open mill, first stage roll temperature 50℃, roll gap 3.5mm, plasticizing for 4min, after wrapping the rolls, thin pass 4 times; second stage roll temperature 65℃, roll gap 1.4mm, thin pass 7 times; final Mooney viscosity ML(1+4)100℃=52, after which the sheet is air-cooled to 25℃ for use.

[0090] S3, acid and alkali resistant modifier in-situ compounding, first-stage intensive mixing: initial temperature of the intensive mixing chamber 75℃, rotor speed 40rpm; add plasticized chloroprene rubber, add activation system, lubricant, and anti-aging stabilizer and mix for 2min; add 40 parts reinforcing filler and 12 parts in-situ modifier in two batches, each batch mixed for 2min; the maximum intensive mixing temperature is 114℃, and the top plug is used to discharge the rubber when the temperature rises, thus obtaining the first-stage compound rubber.

[0091] S4, Low-temperature vulcanization system secondary final refining: The open mill roller temperature is 60℃. After a section of rubber compound completely wraps around the roller, 2.7 parts of low-temperature composite vulcanization system are evenly sprinkled in. The rubber compound is folded 9 times by left and right cutters, with a total folding time of 3 minutes. The highest surface temperature of the rubber compound is 88℃, and a uniform 2.5mm rubber sheet is produced without any white spots of vulcanizing agent agglomeration.

[0092] S5, Rubber compound static curing: The rubber sheet is laid flat with release paper and stored in a constant temperature and ventilation room at an ambient temperature of 25℃ and humidity of 50% for 20 hours in the dark; after curing, the hardness fluctuation of the rubber compound is ≤±1.5HA.

[0093] S6, low-temperature rapid molding and vulcanization: the mold is preheated to 132℃, the film is cut to match the 5mm rubber pad cavity, and the filling amount exceeds the cavity by 7%; a constant pressure of 12MPa is applied when the mold is closed, and the pressure is held for vulcanization for 12 minutes; after vulcanization, the mold is opened quickly and the mold is naturally demolded without sticking or bubble defects; the mold temperature fluctuation is controlled within ±1.5℃.

[0094] S7, after stabilization at room temperature and pressure: the demolded rubber pad is laid flat on a ventilation table and placed at 24℃ for 5 hours to release internal stress; trim the flash and grind the parting burrs; after the appearance and size pass the initial inspection, it is stored and left to stand for 72 hours to obtain the finished acid and alkali resistant rubber pad for pickling tank.

[0095] 3. Application of the finished product performance test data from Example 1 (national standard test method)

[0096] Mechanical properties: tensile strength 17.1 MPa, elongation at break 425%, tear strength 51 kN / m, Shore A hardness 68 HA;

[0097] Acid and alkali resistance: After soaking in 30wt% H2SO4 at room temperature for 720h, the volume swelling rate was 4.2% and the weight change rate was -2.9%; after soaking in 30wt% NaOH at room temperature for 720h, the volume swelling rate was 4.5% and the weight change rate was -3.1%; the sample was intact without bulging, cracking, or pulverization.

[0098] Processing energy consumption data: The comprehensive power consumption per ton of finished product is 172 kWh, and the vulcanization molding time per batch is 12 minutes;

[0099] Mass production yield: The average yield of 30 consecutive batches of production is 99.1%.

[0100] Application Example 2: The application scenario is an acid and alkali resistant EPDM rubber pad for buffering electroplating equipment, 8mm thick industrial pad.

[0101] 1. Raw material weight ratio

[0102] 100 parts of EPDM4045 ethylene propylene diene monomer (EPDM) rubber; 5.5 parts of activation system (4.5 parts zinc oxide + 1 part stearic acid); 47 parts of reinforcing and barrier filler (24 parts silica + 13 parts barite + 10 parts kaolin); 14 parts of acid and alkali resistant in-situ compound modification additives; 3.2 parts of low-temperature rapid composite vulcanization system (1.1 parts MBT, 0.8 parts CBS, 1.3 parts slow-release sulfur, mass ratio 1:0.73:1.18); 3.6 parts of processing lubricant (2.4 parts naphthenic oil + 1.2 parts polyethylene wax); and 2.2 parts of anti-aging stabilizer (1.2 parts 4010NA + 1 part paraffin wax).

[0103] 2. Stepwise preparation process

[0104] S1, Precise raw material proportioning and preparation: EPDM rubber blocks are cut to 8cm, all powders are passed through a 120-mesh sieve, naphthenic oil is added by metering pump, and the weighing error of all raw materials is ≤±0.3%; vulcanization aids are sealed and stored separately away from light.

[0105] S2, segmented constant temperature plasticizing: first stage of open mill, roller temperature 52℃, roller gap 3.8mm, plasticizing for 4.5min, thin pass 4 times; second stage, roller temperature 68℃, roller gap 1.6mm, thin pass 8 times; after plasticizing, Mooney viscosity ML(1+4)100℃=54, air-cooled to room temperature for later use.

[0106] S3, acid and alkali resistant modifier in-situ compounding, first stage of intensive mixing: initial temperature of the intensive mixing chamber 78℃, rotor speed 42rpm; EPDM raw rubber is added, along with the activation system, lubricant, and stabilizer, and mixed for 2.2min; 47 parts of reinforcing filler and 14 parts of in-situ modifying agent are added in two batches, and each batch is mixed for 2min; the peak temperature of the intensive mixing is 116℃, and after reaching the standard, the rubber is discharged to obtain the first stage of compound rubber.

[0107] S4, Secondary final refining of low-temperature vulcanization system: Open mill roll temperature 62℃, after the rubber compound wraps around the roll, slowly sprinkle in 3.2 parts of low-temperature vulcanization composite system, and tumble 8 times with left and right cutters, with a total time of 3.5min; the highest temperature of the rubber compound is 90℃, and a uniform rubber sheet of 2.6mm is produced.

[0108] S5, rubber compound static curing: The rubber sheets are stacked in a single layer with isolation, ambient temperature 26℃, relative humidity 52%, and kept in the dark for 22 hours. The hardness fluctuation of the rubber compound is ≤±2HA.

[0109] S6, low-temperature rapid molding and vulcanization: mold preheated to 135℃, film cut to fit 8mm backing plate cavity, 6% overfill; mold closing pressure 13MPa, constant temperature and pressure vulcanization for 15min; mold temperature fluctuation ≤±2℃, complete demolding without defects.

[0110] S7, after stabilization at room temperature and pressure: release the mold pad at 26℃ and ventilate for 5.5 hours to release the internal stress of vulcanization; trim and grind the flash and burrs; after quality inspection, store and stand for 72 hours to obtain the finished product of the buffer anti-corrosion rubber pad of the electroplating production line.

[0111] 3. Application of Performance Test Data of Finished Products in Example 2

[0112] Mechanical properties: tensile strength 16.5 MPa, elongation at break 460%, tear strength 49 kN / m, Shore A hardness 65 HA;

[0113] Acid and alkali resistance: After immersion in 30% sulfuric acid for 720 hours, the volume swelled by 4.5% and the weight loss was 2.7%; after immersion in 30% sodium hydroxide for 720 hours, the volume swelled by 4.7% and the weight loss was 3.0%, with no damage to the appearance;

[0114] Energy consumption and efficiency: The comprehensive power consumption per ton of finished product is 181 kWh, and the vulcanization time is 15 minutes per batch;

[0115] Mass production stability: 98.7% yield rate for 30 consecutive batches.

[0116] Comparative example: The traditional high-temperature vulcanization process is consistent with the total amount of raw rubber and filler added in Application Example 1.

[0117] 1. The raw materials used in the comparison are free of in-situ compounded modifying agents and adopt a conventional single accelerator high-temperature vulcanization system.

[0118] CR1212 chloroprene rubber 100 parts; zinc oxide 5 parts, stearic acid 1 part; silica 20 parts, barite 11 parts, kaolin 9 parts; barium sulfate single anticorrosive filler 12 parts (non-in-situ compounded powder); traditional high-temperature vulcanization system (ordinary sulfur 2.2 parts, single accelerator DM 1.8 parts); naphthenic oil 3 parts, polyethylene wax 1 part; 4010NA 1 part, paraffin wax 0.8 parts.

[0119] 2. Traditional preparation process parameters

[0120] The plasticizing and internal mixing processes are the same as in Application Example 1, but the in-situ modification internal mixing reaction control is eliminated; the rubber compound is directly vulcanized at high temperature after final mixing; the vulcanization temperature is 158℃, the holding time is 32min, and the molding pressure is 12MPa; there is no light-proof constant temperature curing process, and the rubber sheets are put into vulcanization after being stacked at room temperature for 8h; after demolding, they are placed naturally for only 2h before being put into storage.

[0121] 3. Comparative test data

[0122] Mechanical properties: tensile strength 12.9 MPa, tear strength 36.8 kN / m;

[0123] Acid and alkali resistance: After immersion in 30% sulfuric acid for 720 hours, the sample swelled by 14.6% and lost 8.3% of its weight. After immersion for 180 hours, bulging appeared on the sample surface.

[0124] Energy efficiency: The power consumption per ton of finished product is 316 kWh, the vulcanization time per batch is 32 minutes, and the daily production capacity is only 57% of that in Example 1;

[0125] Mass production yield: The average yield of 30 consecutive batches was 91.2%, with a relatively high proportion of defects such as bubbles, material shortage, and scorching.

[0126] A comparison of the effects of the application examples and the comparative examples shows that, in terms of energy saving and consumption reduction, application examples 1 and 22 save 42% and 39.5% of electricity per ton of finished product, respectively, significantly reduce the heating load of vulcanization, and reduce organic waste gas emissions by 70%, demonstrating significant energy-saving and environmental protection effects. In terms of production efficiency, the vulcanization cycle is shortened by 53% to 62.5%, and the daily capacity of a single piece of equipment is increased by more than 56%, reducing the investment in vulcanization equipment for the same capacity. In terms of corrosion resistance, the swelling rate after long-term immersion in acid and alkali is reduced by 68% to 71%, the media weight loss is significantly reduced, and the product's corrosion resistance service life is doubled. In terms of mechanical strength, the tensile strength is increased by 24%, the tear strength is increased by about 38%, and the pressure-bearing and wear-resistant performance is significantly better than that of products made using traditional processes. In terms of mass production stability, the yield rate is increased by 7 to 8 percentage points, the batch performance fluctuations are smaller, raw material scrap losses are reduced, and the overall production cost is further reduced.

[0127] The embodiments of this invention represent a systematic improvement technology for energy conservation and environmental protection in the traditional manufacturing process of anti-corrosion rubber products. It features low barriers to entry, high energy savings, and simultaneous product performance upgrades. It requires no replacement of existing mainstream rubber processing equipment; only adjustments to the formulation raw material ratios and process parameters such as temperature, time, and rotation speed are needed for rapid implementation. The products cover a full range of acid and alkali resistant rubber pads and industrial anti-corrosion rubber mats for chemical pickling tanks, electroplating production lines, metallurgical acid and alkali equipment, wastewater treatment ponds, and pharmaceutical anti-corrosion equipment. In terms of process adaptability, the low-temperature rapid vulcanization system combined with in-situ compound anti-corrosion modification technology can be extended to the production of other anti-corrosion rubber products such as butyl rubber and fluororubber, not limited to rubber pads alone. Further development can extend to acid and alkali resistant sealing rings, anti-corrosion rubber linings, and cushioning and shock-absorbing anti-corrosion rubber products, offering significant potential for technological derivatives. The entire technical solution includes the cross-linking mechanism of the formulation molecules, the microstructure modification of the filler interface, and the control of the entire industrial process.

[0128] The two application embodiments of this invention employ a low-temperature rapid composite vulcanization system, thereby achieving energy saving, consumption reduction, and shortening the molding cycle. Traditional sulfur vulcanization systems use a single accelerator with high activation energy, requiring temperatures above 150°C to complete full cross-linking, resulting in high energy consumption and long processing times for heating and heat preservation. This invention uses a combination of MBT and CBS dual low-temperature accelerators with slow-release sulfur. The two accelerators form a synergistic catalytic system, significantly reducing the activation energy required for the vulcanization cross-linking reaction. The initial vulcanization temperature is lowered to below 120°C, and a complete and stable rubber cross-linking network can be formed in the low-temperature range of 125–138°C. The slow-release sulfur particles are coated with a small amount of paraffin slow-release layer, which slowly decomposes and releases active sulfur during the vulcanization process, avoiding uneven local cross-linking at low temperatures and ensuring uniform overall cross-linking density of the rubber. The tensile strength and compression set of the finished product are superior to those of traditional high-temperature vulcanized products. In terms of energy saving and efficiency improvement, the vulcanization temperature is reduced by 20-40℃, and the continuous heating power of the vulcanizing machine hot plate and mold is reduced by 32%-45%; the vulcanization molding time is shortened from the traditional 25-40 minutes to 8-18 minutes, the equipment output per unit time is increased, and the idle heating time of the equipment is reduced by more than 60%; the comprehensive power consumption per ton of finished rubber pads can be reduced to 160-190 kWh, which is 30%-45% more energy-saving than the traditional process; after the vulcanization temperature is reduced, the volatilization of small molecule additives in the rubber compound is reduced by 70%, the operating load of the supporting waste gas treatment equipment is reduced, the auxiliary energy consumption is reduced simultaneously, and the overall carbon emissions of the process are significantly reduced.

[0129] Secondly, the embodiments of this invention employ in-situ compounding and intensive mixing technology of acid and alkali resistant modifiers, thereby simultaneously improving the acid and alkali corrosion resistance and mechanical strength of rubber. Existing processes involve simple step-by-step mixing of anti-corrosion fillers and modifying agents. The filler interfaces lack chemical bonds, easily agglomerating and forming channels for media penetration. Improving corrosion resistance requires a significant increase in filler dosage, sacrificing rubber elasticity and strength. This invention directly introduces ternary in-situ compounding and modifying agents in a single intensive mixing step. Under the high-temperature shear environment of intensive mixing, the epoxy-modified montmorillonite epoxy groups and silane nano-barium sulfate silanol groups undergo in-situ interfacial grafting reactions with the unsaturated bonds of the rubber molecular chains. Maleic anhydride-grafted polyolefins act as interfacial compatibility bridges, firmly binding the inorganic barrier filler to the organic rubber matrix. The filler is uniformly dispersed at the nanoscale within the rubber, without significant micron-sized agglomerates. The microstructure brings two performance benefits: First, the nanosheet montmorillonite and nanobarium sulfate form a multi-layered labyrinthine physical barrier structure, which greatly extends the molecular penetration path of acid and alkali media. The volume swelling rate of the rubber pad after immersion in 30% H2SO4 and 30% NaOH solutions at room temperature for 720 hours is ≤4.8%, which is far lower than the 12% to 18% swelling rate of traditional processes, and the long-term corrosion protection service life is more than doubled. Second, the interfacial bonding force between the filler and the rubber matrix is ​​improved, the stress transmission is uniform, the tensile strength of the finished product is increased by 18% to 26%, the tear strength is increased by 22% to 30%, and the pressure-bearing and buffering performance is not affected by the addition of fillers, taking into account both corrosion protection and mechanical performance requirements.

[0130] Third, the complete preparation method of the embodiments of the present invention includes refined and improved supporting processes to adapt to the stable mass production of low-temperature vulcanized rubber compounds in industrial applications. Existing low-temperature vulcanization technology only optimizes the vulcanization formula, while the plasticizing, mixing, curing, and post-treatment processes still use the traditional high-temperature vulcanization operating parameters. Low-temperature vulcanized rubber compounds have poor thermal stability and are prone to mass production defects such as scorching, performance fluctuations, and molding bubbles. The present invention addresses the characteristics of low-temperature vulcanized rubber compounds by systematically adapting and modifying the entire production process: segmented constant-temperature plasticizing precisely controls the Mooney viscosity of the raw rubber to ensure uniform dispersion of subsequent fillers; a first-stage intensive mixing first completes the in-situ reaction of modified additives, followed by low-temperature final mixing before adding them to the vulcanization system, strictly controlling the maximum temperature of the rubber compound throughout the process to prevent premature pre-crosslinking of the vulcanization system; light-proof constant-temperature curing eliminates internal stress during mixing and promotes secondary diffusion of additive molecules; low-temperature short-time molding vulcanization combined with room-temperature slow release of internal stress post-treatment avoids the problem of internal residual stress cracking caused by rapid low-temperature vulcanization. The entire process does not require replacing existing mainstream production equipment such as internal mixers, open mills, and flat vulcanizing machines; only process parameters such as temperature, time, and speed need to be adjusted.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A highly efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads, characterized in that, include: S1. Prepare materials according to the precise proportions of the raw material system; wherein, by weight, the raw material system comprises: 100 parts of acid and alkali resistant base raw rubber, 4-7 parts of activation system, 35-60 parts of reinforcing and barrier filler, 8-16 parts of acid and alkali resistant in-situ compounding and modifying agent, 1.8-3.6 parts of low-temperature rapid composite vulcanization system, 2-5 parts of processing and lubricating agent, and 1.2-2.8 parts of anti-aging stabilizer; wherein, the acid and alkali resistant in-situ compounding and modifying agent comprises silane-modified nano-barium sulfate, epoxy-modified montmorillonite, and maleic anhydride-grafted polyene. The three hydrocarbons are in-situ blended powders; wherein the low-temperature rapid composite vulcanization system is composed of low-temperature accelerator A, low-temperature accelerator B, and slow-release sulfur in a mass ratio of 1:0.6-0.9:1.2-1.6; the vulcanization temperature of the low-temperature rapid molding vulcanization is controlled at 125-138℃, the vulcanization holding time is 8-18 min, and the molding pressure is 10-14 MPa; wherein the low-temperature accelerator A is dibenzothiazole disulfide MBT, and the low-temperature accelerator B is N-cyclohexyl-2-benzothiazole sulfenamide CBS; S2, segmented constant temperature plasticizing; S3, based on the acid and alkali resistant in-situ compounding and modifying agent, perform a first-stage intensive mixing of the acid and alkali resistant modifier in-situ compounding agent; S4, low-temperature vulcanization system, secondary final refining; S5, rubber compound is left to mature under static conditions; S6, Low-temperature rapid compression molding is performed based on the aforementioned low-temperature rapid composite vulcanization system; S7, post-processing for stabilization at room temperature and pressure.

2. The efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads according to claim 1, characterized in that, The matrix raw rubber is any one or a blend of two of chloroprene rubber CR1212, nitrile rubber NBR3305, and ethylene propylene diene monomer rubber EPDM4045; the activation system is a compound of indirect zinc oxide and stearic acid in a mass ratio of 3.2 to 4.5:1; the reinforcing and barrier filler is a compound of precipitated silica, barite powder, and calcined kaolin in a mass ratio of 2:1.1:0.

8.

3. The efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads according to claim 2, characterized in that, The anti-aging stabilizer is a compound of 4010NA antioxidant and microcrystalline wax at a ratio of 1:0.5; the processing lubricant is a compound of naphthenic rubber processing oil and polyethylene wax at a mass ratio of 2.5:

1.

4. The efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads according to claim 3, characterized in that, S1 includes: S11, Weigh all solid powder additives, granular raw rubber and liquid processing aids according to the formula weight parts of the raw material system; wherein, the weighing error of all raw materials is controlled to be ≤±0.3wt%; the raw materials are stored in separate areas, and the vulcanization system is stored separately in a sealed and light-proof manner to avoid premature pre-crosslinking; S12, the granular raw rubber is pre-cut into 5-10cm rubber blocks, and the solid powder additive is sieved through a 120-mesh standard sieve to remove agglomerates; the liquid processing additive is quantitatively delivered using a constant temperature metering pump.

5. The efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads according to claim 4, characterized in that, S2 includes: S21, the cut rubber blocks are fed into a two-roll mill for two-stage plasticizing; the first stage plasticizing has a roll temperature of 45-55℃, a roll gap of 3.0-4.0mm, a plasticizing time of 3-5min, and the rubber compound is passed through the mill 4 times after completely covering the rolls; the second stage plasticizing has a roll temperature of 60-70℃, a roll gap of 1.0-1.8mm, and is passed through the mill 6-8 times. S22, Quality control of the raw rubber plasticizing process is carried out based on the plasticizing endpoint condition parameters; wherein, the plasticizing endpoint condition parameters are to control the Mooney viscosity ML(1+4) of the rubber compound at 100°C to be 48-56. S23, based on meeting quality control requirements, is sheeted out after plasticizing and cooled to room temperature for later use.

6. The efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads according to claim 5, characterized in that, S3 includes: S31, the plasticized raw rubber is fed into a closed internal mixer, wherein the initial temperature of the mixing chamber of the closed internal mixer is 70-80℃ and the rotor speed is 35-45rpm. S32 is added sequentially to the activation system, processing lubricant and anti-aging stabilizer, and mixed for 1.5 to 2.5 minutes; S33, reinforcing and barrier fillers and acid and alkali resistant in-situ compounding modifiers are added in two batches. After each batch is added, the mixture is mixed for 2 minutes. The maximum temperature of the mixing chamber of the closed mixer is controlled to not exceed 118℃ throughout the process. After the material reaches the preset temperature, the top plug is raised to discharge the rubber, and a section of mixed rubber is obtained.

7. The efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads according to claim 6, characterized in that, S4 includes: S41, the section of compounded rubber is fed into the roll wrapper of a two-roll mill, with a roll temperature of 55-65°C; S42 is slowly and evenly added to the low-temperature rapid compound vulcanization system, and the mixture is turned over by the left and right cutters at least 8 times, with a total turning time of 2.5 to 4 minutes; the surface temperature of the rubber compound should not exceed 92°C throughout the final mixing process to prevent the risk of scorching. S43, after final refining, produces uniformly 2.2-2.8mm thick rubber sheets without localized white spots caused by vulcanizing agent aggregation.

8. The efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads according to claim 7, characterized in that, S5 includes: S51, after the final refining is completed, the film is laid flat on a clean and ventilated material rack, stacked in a single layer, with anti-stick paper separating the film sheets; S52, set the ambient temperature to 22~28℃, the relative humidity to 40%~60%, and let it stand in the dark for 16~24h to obtain the cured film; the curing process completes the diffusion of additive molecules and the secondary bonding at the filler interface, eliminates the internal stress of the mixing, and the hardness fluctuation range of the cured film is ≤±2HA.

9. The efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads according to claim 8, characterized in that, S6 includes: S61, the cured film is cut to match the size of the rubber pad mold cavity, and the film filling amount exceeds the cavity volume by 5% to 8%; S62, preheat the mold to 125-138℃, and apply a constant pressure of 10-14MPa after closing the mold; S63, low temperature holding pressure vulcanization for 8-18 minutes, after vulcanization, quickly open the mold and demold. After demolding, the rubber pad naturally detaches from the mold, without sticking, missing material and air bubbles; the temperature fluctuation of the mold is controlled ≤±2℃.

10. The efficient low-temperature vulcanization preparation method for acid and alkali resistant rubber pads according to claim 9, characterized in that, S7 includes: S71, after demolding, lay the rubber pad flat on a ventilated workbench and let it rest naturally at room temperature (20-30℃) for 4-6 hours to release the internal stress of vulcanization. S72, trim the edge burrs and polish the parting surface; S73, after completing the initial inspection of size and appearance, is placed in a ventilated storage environment and left to stand for 72 hours to eliminate residual small molecule volatiles from sulfurization, finally obtaining the finished acid and alkali resistant rubber pad.

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