Strong-acid-resistant and high-wear-resistant composite rubber material as well as preparation method and application thereof

Abstract

The invention provides a strong-acid-resistant and high-wear-resistant composite rubber material as well as a preparation method and application thereof. The fluororubber comprises the following raw materials (in parts by mass): 100 parts of fluororubber (FKM); 20 parts of an inorganic filler; 5 parts of polytetrafluoroethylene; 2 parts of bisphenol AF; 5 parts of an accelerant BPP; 3 parts of calcium hydroxide; and 4 parts of magnesium oxide. Therefore, moderate reinforcement can be provided, and embrittlement caused by excessive crosslinking can be avoided. Meanwhile, the rubber material has excellent stability to strong oxidizing acid, is not easy to erode, is beneficial to keeping the softness and high elasticity of the rubber material, and is beneficial to reaching the target hardness. And magnesium oxide is used as an acid acceptor. The synergistic effect with calcium hydroxide is realized. And a model (such as Japanese synergy MGO (XH)-150) with high activity and large specific surface area is used, so that the acid absorption capacity is stronger. PTFE has an extremely low friction coefficient and is dispersed in rubber in the form of small particles, and when the surface of a product is rubbed, the PTFE can migrate to the surface to form a layer of self-lubricating film, so that the friction force and abrasion are greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of electrochemical technology, and in particular to a strong acid-resistant and highly wear-resistant composite rubber material, its preparation method, and its application. Background Technology

[0002] A rubber roller is a roller-shaped product made by vulcanizing a metal or other material core covered with rubber. In industrial rubber rollers, those used in the metallurgical / steel rolling industry are classified as high-performance rollers for special operating conditions, operating in environments where they are immersed in 80°C, 20% concentration strong oxidizing acid. Good acid resistance and abrasion resistance are required. Ordinary fluororubber is prone to cross-linking degradation, surface cracking, decreased hardness, and accelerated wear, leading to short lifespan, frequent replacements, and impacting product surface quality and production efficiency. Existing rubber roller formulations have poor abrasion resistance and acid resistance, resulting in a short service life.

[0003] Therefore, developing a composite rubber material with high acid resistance and wear resistance is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a high-temperature-resistant, high-pressure-resistant, and high-hardness rubber composite material and its preparation method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: According to one aspect of this application, a strong acid-resistant and highly abrasion-resistant composite rubber material is provided, which is made from raw materials comprising the following components in parts by weight: Rubber matrix: 100 parts; Inorganic filler: 15-25 parts; Polytetrafluoroethylene: 3-8 parts; Bisphenol AF: 1-4 parts; Accelerator: 3-8 parts; Calcium hydroxide: 2-4 parts; Magnesium oxide: 2-5 parts; In some embodiments, the rubber matrix is ​​fluororubber FKM; In some embodiments, the inorganic filler is carbon black N990.

[0006] In some embodiments, the raw material components are: Rubber matrix: 100 parts; Inorganic filler: 20 parts; Polytetrafluoroethylene: 5 parts; Bisphenol AF: 2 parts; Accelerator: 5 parts; Calcium hydroxide: 3 parts; Magnesium oxide: 4 parts.

[0007] In some implementations, the accelerator is BPP.

[0008] According to another aspect of this application, a method for preparing a high-temperature-resistant, high-pressure-resistant, and high-hardness rubber composite material as described above is provided, characterized by comprising the following steps: S1: Add the rubber matrix, calcium hydroxide, magnesium oxide, and polytetrafluoroethylene into a mixer according to the specified ratio, mix for 3-5 minutes until the temperature reaches 70-100℃, then remove the hammer and clean. S2: Second step, add inorganic filler to the mixture obtained in step S1 according to the ratio, mix for 3-5 minutes, until 100-130℃, then remove the hammer and clean. S3: The third step is to continue mixing the rubber compound obtained in step S2 for about 3-5 minutes until it reaches 130-140℃. Then, discharge the rubber and repeatedly pass it through a rolling mill to form thin sheets. The sheets are then cooled to room temperature. S4: Add bisphenol AF and accelerator to the cooled rubber compound in step S3 according to the formula, mix in an internal mixer for 3-8 minutes until 70-90℃, discharge the rubber after uniform mixing, and obtain the high temperature and pressure resistant, high hardness composite rubber material.

[0009] Therefore, the technical solution of this application first premixes the small materials with the raw rubber, and then adds inorganic fillers, which can achieve better dispersion; at the same time, controlling the temperature and time makes the dispersion and mixing more uniform, and some materials will react better at a certain temperature, but the temperature cannot be too high, otherwise the mixed rubber will cross-link prematurely, that is, the phenomenon of "scorching and dead rubber".

[0010] In some implementations... In step S1, the temperature is 80℃ and the time is 3 minutes. And / or in step S2, the temperature is 120°C; the time is 3 minutes; And / or in step S3, the temperature is 130°C; the time is 3 minutes; And / or in step S4, the mixing time is 3 minutes and the temperature is 85°C.

[0011] According to another aspect of this application, there is an application of the aforementioned composite rubber material in the preparation of a rubber calendering roller.

[0012] Compared with the prior art, this application has the following advantages: Fluororubber (FKM) uses FE2602, which has high fluorine content and excellent chemical resistance.

[0013] The inorganic filler selected is 20 parts of carbon black N990 (MT Black). Key selection criteria: N990 is a medium-temperature cracking carbon black with large particle size and low structure. This provides appropriate reinforcement, preventing excessive cross-linking and embrittlement. It also exhibits excellent stability against strong oxidizing acids, is not easily corroded, and helps maintain the rubber compound's softness and high elasticity, facilitating the achievement of the target hardness. Calcium hydroxide acts as an acid acceptor. Its key role is to neutralize acidic substances (especially HF) generated during rubber vulcanization and use, which is crucial for maintaining acid resistance and preventing internal corrosion and cracking of the product. Magnesium oxide also acts as an acid acceptor, working synergistically with calcium hydroxide. Using a highly active model with a large specific surface area (such as Elastomag 170) enhances its acid absorption capacity. The mechanism of polytetrafluoroethylene (PTFE): PTFE has an extremely low coefficient of friction (approximately 0.04). It is dispersed in rubber as tiny particles. When the product surface is rubbed, PTFE migrates to the surface, forming a self-lubricating film, thereby significantly reducing friction and wear.

[0014] Therefore, the material obtained in this application possesses extremely excellent chemical resistance, is fully compatible with fluororubber, and can withstand any strong oxidizing acid. It significantly reduces the dynamic coefficient of friction and improves wear resistance. It has minimal impact on hardness. Detailed Implementation

[0015] The present invention will be further described below with reference to embodiments.

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0017] I. Specific Implementation Examples and Comparative Examples Example 1 This embodiment provides a strong acid-resistant and highly wear-resistant composite rubber material, the raw material composition (parts by weight) of which is as follows: Fluororubber (FKM): 100 parts; Inorganic filler: 20 parts; Polytetrafluoroethylene: 5 parts; Bisphenol AF: 2 parts; Accelerator BPP: 5 parts; Calcium hydroxide: 3 parts; Magnesium oxide: 4 parts.

[0018] The component grades are: fluororubber FE2602, carbon black Cancarb N990 (MT Black), carbon black CABOTN550, carbon black CABOT N330, polytetrafluoroethylene POLYMIST F5AR, bisphenol AF (3F), accelerator BPP, calcium hydroxide NICC5000, and magnesium oxide MGO (XH)-150.

[0019] The preparation method includes the following steps: S1: Add the rubber matrix, calcium hydroxide, magnesium oxide, and polytetrafluoroethylene into the internal mixer according to the ratio, mix for 3 minutes until 80°C, then remove the hammer and clean. S2: Second step, add inorganic filler to the mixture obtained in step S1 according to the ratio, mix for 3 minutes, until 120°C, then remove the hammer and clean. S3: The third step is to continue mixing the rubber compound obtained in step S2 for 3 minutes until it reaches 140°C. Then, discharge the rubber compound and repeatedly tumble it on a two-roll mill. The sheet is then cooled to room temperature. S4: Add bisphenol AF and accelerator BPP to the cooled rubber compound in step S3 according to the ratio, mix in an internal mixer for about 3 minutes until it reaches 85°C, discharge the rubber after it is uniform, and you will get the high temperature and pressure resistant high hardness composite rubber material.

[0020] Example 2 The difference from Example 1 is that the raw material composition (parts by weight) is as follows: Fluororubber (FKM): 100 parts; Inorganic filler: 15 parts; Polytetrafluoroethylene: 3 parts; Bisphenol AF: 1 part; Accelerator BPP: 3 parts; Calcium hydroxide: 2 parts; Magnesium oxide: 2 parts.

[0021] The fluororubber (FKM) used is FE2602, and the inorganic filler carbon black is N990 (MT Black). Everything else is exactly the same as in Example 1.

[0022] Example 3 The difference from Example 1 is that the raw material composition (parts by weight) is as follows: Fluororubber (FKM): 100 parts; Inorganic filler: 25 parts; Polytetrafluoroethylene: 8 parts; Bisphenol AF: 4 parts; Accelerator BPP: 8 parts; Calcium hydroxide: 4 parts; Magnesium oxide: 5 parts.

[0023] The fluororubber (FKM) used is FE2602, and the inorganic filler carbon black is Cancarb N990 (MT Black). Everything else is exactly the same as in Example 1.

[0024] Comparative Example 1 The difference from Example 1 is that the inorganic filler was changed to carbon black CABOT N550; the remaining components, dosages, and preparation methods are exactly the same as in Example 1.

[0025] Comparative Example 2 The difference from Example 1 is that the inorganic filler was changed to carbon black CABOT N330; the remaining components, dosages, and preparation methods are exactly the same as in Example 1.

[0026] Comparative Example 3 The difference from Example 1 is that the amount of carbon black N990 was adjusted to 0 parts; the other components, amounts, and preparation methods are exactly the same as in Example 1.

[0027] Comparative Example 4 The difference from Example 1 is that the amount of polytetrafluoroethylene (PTFE) POLYMIST F5AR was adjusted to 0 parts; the other components, amounts, and preparation methods are exactly the same as in Example 1.

[0028] Comparative Example 5 The difference from Example 1 is that the amount of accelerator BPP was adjusted to 0 parts; the other components, amounts, and preparation methods are exactly the same as in Example 1.

[0029] Comparative Example 6 The difference from Example 1 is that the amount of calcium hydroxide was adjusted to 0 parts; the other components, amounts, and preparation methods are exactly the same as in Example 1.

[0030] Comparative Example 7 The difference from Example 1 is that the amount of calcium hydroxide and magnesium oxide was adjusted to 0 parts; the remaining components, amounts, and preparation methods are exactly the same as in Example 1.

[0031] The proportions of the above embodiments and comparative examples can be found in Table 1 below: Examples and comparative formulations (based on 100 parts by weight of rubber matrix) Table 1 - Examples and Comparative Examples

[0032] All of the above components are commercially available.

[0033] II. Experimental Results Data of Examples and Comparative Examples The materials in the above embodiments and comparative examples were subjected to performance tests. Specifically, the performance tests were conducted in accordance with GB / T 531.1 "Test Method for Indentation Hardness of Vulcanized Rubber or Thermoplastic Rubber - Part 1: Shore Hardness Tester Method (Shore Hardness)"; GB / T 528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber"; GB / T 529-2008 "Determination of Tear Strength of Vulcanized Rubber or Thermoplastic Rubber (Pants-Shaped, Right-Angle and Crescent-Shaped Specimens)"; GB / T 9867-2008 "Determination of Abrasion Resistance of Vulcanized Rubber or Thermoplastic Rubber (Rotating Roller Abrasion Test Method)"; and GB / T 1690-2010 "Test Method for Liquid Resistance of Vulcanized Rubber or Thermoplastic Rubber". The performance test results are shown in Table 2 below. Table 2 - Performance Test Results

[0034] Based on the above embodiments and comparative data, the technical solution of this application can achieve the following performance: Shore hardness A is 95±2; tensile strength / MPa ≥15; elongation at break / % ≥150; tear strength kN / m ≥25; resistance to strong oxidizing acid at 50℃×72H, hardness change rate% is ±3; strength change rate% is ±20; elongation change rate% is ±20; volume change rate% is ±5; DIN abrasion cm 3 ≤80.

[0035] As can be seen from the above embodiments and comparative data, this application is not a simple sum of the functions of each component, but rather the result of careful design and synergistic cooperation between the components and their proportions. Among them, fluororubber (FKM) raw rubber: This is the cornerstone of the entire design. The CF bond energy in the FKM molecular chain is extremely high, and the structure is extremely stable, providing the material with top-notch inherent chemical corrosion resistance, including resistance to strong oxidizing acids. Bisphenol vulcanization system: Compared with peroxide systems, the CC crosslinking bonds formed by bisphenol vulcanization are more stable, with superior heat and chemical resistance, providing a solid "skeleton" for the matrix. "Acid acceptor" protective network (calcium hydroxide / magnesium oxide): These can promptly neutralize the hydrogen fluoride (HF) that may be produced by the degradation of fluororubber in high-temperature or acidic environments, preventing HF from triggering "autocatalytic degradation," thereby greatly extending the service life of the product in harsh environments. N990 (medium-temperature cracked carbon black) is selected based on its acid resistance principle: N990 has a large particle size, small specific surface area, high degree of graphitization, and extremely inert chemical properties. It is difficult to be corroded in strong oxidizing acids.

[0036] Furthermore, the solution proposed in this application improves wear resistance: while carbon black N990 has poor wear resistance compared to smaller particle sizes like N330, the synergistic addition of PTFE, which has the lowest coefficient of friction, allows it to migrate to the surface during friction, forming a self-lubricating film that transforms intense "grinding" into gentle "sliding." This fundamentally changes the form of wear, significantly reducing the wear rate. These two aspects determine the service life of the rubber roller; better performance results in a longer service life.

[0037] The above descriptions are merely some embodiments of the present invention. It should be noted that those skilled in the art can make other modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A strong acid resistant, high abrasion resistant composite rubber material, characterized by, The raw material is made of the following components in mass fraction: Rubber matrix: 100 parts; Inorganic filler: 15-25 parts; Polytetrafluoroethylene: 3-8 parts; Bisphenol AF: 1-4 parts; Accelerator: 3-8 parts; Calcium hydroxide: 2-4 parts; Magnesium oxide: 2-5 parts.

2. The rubber material according to claim 1, wherein, the rubber matrix is fluororubber FKM.

3. The rubber material according to claim 1, wherein, the inorganic filler is carbon black N990.

4. The rubber material according to claim 1, characterized in that, The raw material components are: Rubber matrix: 100 parts; Inorganic filler: 20 parts; Polytetrafluoroethylene: 5 parts; Bisphenol AF: 2 parts; Accelerator: 5 parts; Calcium hydroxide: 3 parts; Magnesium oxide: 4 parts.

5. The rubber material according to claim 1, characterized in that, The accelerator is BPP.

6. A method of producing the high temperature resistant, high pressure resistant, high hardness rubber composite material according to any one of claims 1 to 5, characterized by, The method comprises the following steps: S1: Put the rubber matrix, calcium hydroxide, magnesium oxide and polytetrafluoroethylene into the internal mixer according to the proportion, mix for 3-5 minutes, to 70-100℃, and clean the hammer; S2: In the second step, add the inorganic filler to the mixture obtained in step S1 according to the proportion, mix for 3-5 minutes, to 100-130℃, and clean the hammer; S3: In the third step, continue to mix the rubber compound obtained in step S2 for 3-5 minutes, to 130-140℃, then discharge the rubber compound, and thin pass on the open mill for multiple times, and cool to room temperature; S4: Add bisphenol AF and accelerator to the cooled rubber compound in step S3 according to the proportion, mix in the internal mixer for 3-8 minutes, to 70-90℃, and discharge the rubber compound after uniform, to obtain the high-temperature-resistant and pressure-resistant high-hardness composite rubber material.

7. The method according to claim 6, wherein, in step S1, the temperature is 80℃, and the time is 3 minutes; and / or in step S2, the temperature is 120℃, and the time is 3 minutes; and / or in step S3, the temperature is 130℃, and the time is 3 minutes; and / or in step S4, the mixing time is 3 minutes, and the temperature is 85℃.

8. Use of the composite rubber material according to any one of claims 1-5 in the preparation of a rubber calender roller.

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