Low-hardness sponge rubber mixing production process and production line

Abstract

The present application relates to a kind of low hardness sponge rubber mixing production process and production line, it is related to mixing rubber processing technical field, the existing sponge rubber strip surface has carbon black particle precipitation, the problem of many impurity particles on the surface of rubber strip, including the following steps: A mixing rubber mixing, B mixing rubber mixing and cooling stop and ripening, before A mixing rubber mixing, first to the carbon black, oil softening agent pretreatment, pretreatment includes the following steps: material preparation, static adsorption treatment and dynamic stirring treatment;With the effect that carbon black and oil softening agent are fully infiltrated by static adsorption treatment and dynamic stirring treatment, the low hardness sponge mixing rubber carbon black dispersed is excellent, and there is no problem of agglomeration dispersion.

Description

Technical Field

[0001] This invention relates to the field of rubber compounding technology, and in particular to a low-hardness sponge rubber compounding process and production line. Background Technology

[0002] The formulation of low-hardness foam generally includes the following seven major systems: raw rubber system, reinforcing and filling system, softening and plasticizing system, activation system, foaming system, functional additive system, and vulcanization accelerator system. Among them, the reinforcing and filling system and the softening and plasticizing system are mainly used to adjust the hardness of the rubber compound. Because foam rubber needs to achieve uniform foaming, low density, high foaming volume, low Mooney viscosity, and high plasticity, the hardness of the compound is generally lower, usually between 40 and 55 Shore A. This means that the amount of softening and plasticizing agent used in the formulation design should be close to or greater than that of the reinforcing and filling system. The excessive use of a strong filler system results in a large amount of softening plasticizer being added during the mixing process. This leads to a low shear force in the internal mixer during mixing, making it impossible to break down and disperse the wet-granulated carbon black particles. Consequently, poor carbon black dispersion easily occurs, with the mixed rubber coating containing undispersed carbon black. Even after multiple refining and thin-passing processes on the open mill, the effect is not ideal. In the subsequent extrusion and vulcanization of sponge strips, problems such as carbon black particles precipitating on the surface of the sponge strips, a large number of impurities on the surface of the strips, poor skin formation, an uneven surface, and a large number of defective and scrapped products are likely to occur.

[0003] Therefore, a suitable process route for low-hardness sponge compound is needed to solve the existing problems. Summary of the Invention

[0004] The purpose of this invention is to provide a low-hardness sponge rubber compounding production process, which solves the problems of existing processes that easily result in carbon black particle precipitation on the surface of the sponge rubber strips, a large number of impurity particles on the surface of the rubber strips, poor skin formation on the surface of the rubber strips, an uneven surface, and a large number of defective products.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a low-hardness sponge rubber compounding production process, comprising the following steps: S1, A rubber compounding: First, the raw materials required for preparing A rubber compound are mixed according to the raw material ratio and addition order. After mixing, the rubber is discharged, cooled and filtered to obtain A rubber compound material. S2 and B rubber compounding: The A rubber compound in S1 is mixed with the raw materials required for preparing B rubber compound according to the raw material ratio and addition order until the A rubber compound and the raw materials required for preparing B rubber compound are fully mixed and then discharged, cooled and filtered to obtain the B rubber compound. S3. Cooling and maturation: The B compound material filtered in S2 is allowed to stand and cool down. In step S1, before mixing rubber A, the carbon black and oil softener required for preparing rubber A are pretreated. The pretreatment includes the following steps: S01. Material preparation: Carbon black and oil softener are weighed multiple times. Each quantitative weighing of carbon black is divided according to the total weight of carbon black and the number of times it is laid. Each quantitative weighing of oil softener is also divided according to the total weight of oil softener and the number of times it is sprayed. S02. Static adsorption treatment: The carbon black weighed in S01 is laid layer by layer. The oil softener weighed in S01 is evenly sprayed on the surface of each layer of carbon black. After each oil softener is sprayed onto the surface of the carbon black, it is left to stand for a set time so that the oil softener can completely penetrate into the carbon black. S03, Dynamic stirring treatment: The carbon black impregnated with oil softener in S02 is thoroughly stirred and mixed and then allowed to stand and cool. Heating is performed during both the static adsorption process in step S02 and the dynamic stirring process in step S03.

[0006] Furthermore, in step S02, the carbon black is laid 3-5 times, and the set standing time for each step in step S02 is 5-10 minutes.

[0007] Furthermore, the heating temperature during the static adsorption process in step S02 and the dynamic stirring process in step S03 is 60℃~80℃.

[0008] Furthermore, in step S03, the stirring speed gradually increases from slow to fast, and the stirring speed is 60 r / min to 100 r / min, while the settling time is 1 h to 2 h.

[0009] Furthermore, in step S1, the mixing of rubber A includes internal mixing and open mixing of rubber A, and the discharge temperature of internal mixing of rubber A is 165℃~175℃.

[0010] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: This invention discloses a low-hardness sponge rubber compounding process. Before processing the low-hardness sponge rubber, carbon black and oil softener are pre-treated and mixed together. During operation, a layer of carbon black is spread and a layer of oil softener is sprayed. Through multiple operations, the oil softener can be better impregnated in the carbon black. Then, the carbon black impregnated with oil softener is thoroughly stirred and mixed. Finally, the well-stirred carbon black and oil mixture is mixed with the remaining raw materials for processing the low-hardness sponge rubber according to the addition order and proportion, thereby producing the sponge rubber compound. In this process, static adsorption treatment and dynamic stirring treatment are first used to fully impregnate the carbon black and oil softener together, so that the processed low-hardness sponge rubber compound has excellent carbon black dispersion and no problem of clumping. During the extrusion process, the surface of the sponge rubber sealing strip is smooth, the pass rate is high, and the scrap rate is low, which greatly saves production costs for enterprises and improves efficiency and production capacity.

[0011] The present invention provides a low-hardness sponge rubber compounding production line, including an A rubber compounding device and a B rubber compounding device, and also includes a pretreatment device, wherein the pretreatment device includes a carbon black conveying device, an oil conveying device and a stirring device. The carbon black conveying device includes a carbon black weighing device for weighing carbon black and a carbon black conveying pipe for conveying carbon black into the stirring device. The oil conveying device includes an oil weighing component for weighing the oil softener and an oil conveying pipe connecting the oil weighing component and the stirring device. The oil conveying pipe is equipped with a high-pressure oil pump for pumping the oil softener into the stirring device. The liquid outlet end of the oil conveying pipe is equipped with an atomizing nozzle for spraying the oil softener onto the carbon black conveyed to the stirring device. The stirring device is used to stir and mix carbon black impregnated with oil softener. The stirring device includes a stirring vessel and a heating component for heating the stirring vessel.

[0012] Furthermore, both the A rubber mixing device and the B rubber mixing device include an internal mixer, an open mill that works in conjunction with the internal mixer, and a filter assembly.

[0013] Furthermore, the filter element has a mesh size of 100-150.

[0014] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: This invention discloses a low-hardness sponge rubber compounding production line. Before the rubber compounding in the A and B compounding units, a pretreatment device pre-stirs and mixes carbon black and oil softener, allowing the oil softener to better impregnate the carbon black. Atomizing nozzles further atomize and evenly spray the oil softener onto the carbon black. The resulting low-hardness sponge rubber, processed sequentially through the A and B compounding units, exhibits excellent carbon black dispersion without clumping or incomplete dispersibility. During extrusion, the sponge rubber sealing strip has a smooth surface, resulting in a high pass rate and low scrap volume, significantly reducing production costs and improving efficiency and capacity for enterprises. Attached Figure Description

[0015] The following sections will describe some specific embodiments of the invention in a detailed manner by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the production line in a preferred embodiment of the present invention; Figure 2 This is a flow chart of the carbon black softener stirring process in a preferred embodiment of the present invention; Figure 3 This is a process flow diagram of low-hardness sponge rubber compounding in a preferred embodiment of the present invention.

[0016] The reference numerals in the attached figures are explained as follows: 1. Stirring device; 11. Stirring vessel; 12. Heating assembly; 2. Oil conveying device; 21. Oil weighing assembly; 22. Oil conveying pipeline; 23. High-pressure oil pump; 24. Atomizing nozzle; 3. Carbon black conveying device; 31. Carbon black weighing device; 32. Carbon black conveying pipeline; 4. A rubber mixing and compounding unit; 41. A rubber internal mixer; 42. A rubber open mill; 43. A rubber filtration unit; 5. B rubber mixing and compounding device; 51. B rubber internal mixer; 52. B rubber open mill; 53. B rubber filtration device. Detailed Implementation

[0017] 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.

[0018] 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.

[0019] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0020] refer to Figure 1 The present invention provides a low-hardness sponge rubber compounding production line, including an A rubber compounding device 4 and a B rubber compounding device 5, and also includes a pretreatment device, which includes a carbon black conveying device 3, an oil conveying device 2 and a stirring device 1. The carbon black conveying device 3 includes a carbon black weighing device 31 for weighing carbon black and a carbon black conveying pipe 32 for conveying carbon black into the mixing device 1. The oil conveying device 2 includes an oil weighing component 21 for weighing the oil softener and an oil conveying pipe 22 connecting the oil weighing component 21 and the stirring device 1. The oil conveying pipe is equipped with a high-pressure oil pump 23 for pumping the oil softener into the stirring device 1. The outlet end of the oil conveying pipe 22 is equipped with an atomizing nozzle 24 for spraying the oil softener onto the carbon black conveyed to the stirring device 1. When the oil softener is pumped into the stirring device 1 by the high-pressure oil pump 23, the atomizing nozzle 24 sprays the oil softener into a mist and evenly onto the surface of the carbon black, increasing the contact area between the oil softener and the carbon black, thereby allowing the oil softener to better penetrate the carbon black. The stirring device 1 is used to stir and mix carbon black impregnated with oil softener; the stirring device 1 includes a stirring vessel 11 and a heating component for heating the stirring vessel 11; the heating component keeps the stirring vessel in a heated state, so as to accelerate the adsorption rate and activity between carbon black and oil softener when stirring carbon black impregnated with oil softener.

[0021] A rubber mixing device 4 is used to mix the well-mixed carbon black oil with the remaining raw materials for preparing A rubber, so that the carbon black oil and the remaining raw materials for preparing A rubber are better mixed together. A rubber mixing device 4 includes an A rubber internal mixer 41, an A rubber open mill 42 that cooperates with the A rubber internal mixer 41, and an A rubber filter device 43. The B rubber mixing device 5 is used to mix, filter, and cool the prepared A rubber with the remaining raw materials for preparing B rubber. The B rubber mixing device includes a B rubber internal mixer 51, a B rubber open mill 52 that cooperates with the B rubber internal mixer 51, and a B rubber filtration device 53.

[0022] refer to Figure 1 , Figure 2 and Figure 3 The mixing and production process for this low-hardness sponge adhesive includes the following steps: First, the carbon black and oil softener are pretreated. The pretreatment includes the following steps: S01. Material preparation: The corresponding carbon black and oil softener are weighed multiple times using the carbon black weighing device 31 and the oil weighing component 21. Each quantitative weighing of carbon black is divided according to the total weight of carbon black and the number of times it is laid. Each quantitative weighing of oil softener is also divided according to the total weight of oil softener and the number of times it is sprayed. S02. Static adsorption treatment: The quantitatively weighed carbon black from S01 is transported to the mixing tank 11 through the carbon black conveying pipe 32 and laid layer by layer. The surface of each layer of carbon black is sprayed with the quantitatively weighed oil softener from S01. After each spraying of the oil softener onto the surface of the carbon black, it is allowed to stand for a set time of 5 to 10 minutes to ensure that the oil softener is completely immersed in the carbon black. After the multiple layers of carbon black and oil softener are laid, the standing time is continued to ensure that the overall standing time is 1 to 2 hours to ensure that the oil softener is better and more completely immersed in the carbon black. The oil softener is sprayed out through the atomizing nozzle 24 to evenly spray the oil softener onto the carbon black and increase the contact area between the oil softener and the carbon black.

[0023] S03. Dynamic stirring treatment: The carbon black impregnated with oil softener in S02 is thoroughly stirred and mixed, then allowed to stand and cool. The stirring tank 11 is started, and the carbon black containing the oil softener is stirred and mixed through the stirring tank 11 at a speed of 60 r / min to 100 r / min. The stirring speed is initially slow and then gradually increases to further break up the carbon black particles and thoroughly mix them with the oil softener. During the adsorption process of carbon black and oil softener, and during the stirring process, the stirring tank 11 is heated at a temperature between 60℃ and 80℃. Heating accelerates the adsorption rate and activity between the carbon black and the oil softener. After the carbon black and oil softener are thoroughly stirred and mixed through the stirring tank 11, the mixture is allowed to stand for 1 to 2 hours to cool. Finally, the stirred and cooled carbon black oil is weighed according to the formula and prepared for mixing in the mixing unit. S1 and A rubber compounding: The carbon black oil in S03 is weighed according to the formula and placed into the A rubber compounding internal mixer 41. Then, the raw materials required for preparing A rubber compounding are added to the A rubber compounding internal mixer 41 according to the proportion and addition order and are mixed until the carbon black oil and the raw materials required for preparing A rubber compounding are completely mixed. After the rubber compounding is discharged, the discharged rubber compound is rolled out into strips through the A rubber compounding open mill 42 and cooled to the set temperature. Then, the rubber strips are filtered for impurities through the A rubber compounding filter device 43 to obtain A rubber compounding (A rubber compounding refers to the compounded rubber without vulcanizing agent and accelerator). S2, B compounding: The A compound from S1 is mixed with the raw materials required for preparing B compound. First, the A compound is placed in the B compound internal mixer 51. Then, the raw materials required for preparing B compound are added to the B compound internal mixer 51 according to the proportion and addition order and mixed until the A compound and the raw materials required for preparing B compound are completely mixed. After the rubber is discharged, the discharged rubber is refined and sheeted through the B compound open mill 52 and cooled to the set temperature. Then, the rubber sheet is filtered again for impurities through the B compound filter device 53 to obtain B compound (B compound refers to the compounded rubber with added vulcanizing agent and accelerator). S3. Cooling and maturation: The B compound material filtered in S2 is allowed to stand and cool down for more than 24 hours to ensure that the raw materials are mutually impregnated, thereby obtaining the required low-hardness sponge compound.

[0024] refer to Figure 1 , Figure 2 and Figure 3 Specifically, when processing A-grade rubber compound, the overall mixing capacity of the A-grade rubber mixing mill 41 should be increased by 10% to 20% compared to the conventional mixing capacity. This increases the shear force of the A-grade rubber compound on the A-grade rubber compound, allowing for better dispersion of the carbon black oil softener after mixing. The top bolt pressure of the A-grade rubber mixing mill 41 should also be 10% to 30% higher than the conventional pressure, reaching 6 kgf to 7 kgf, to obtain a higher and greater shear force from the mill rotor. The A-grade rubber mixing mill 41 performs 4 to 5 stages of mixing, with the rotor speed of the A-grade rubber mixing mill 41 at a high speed for the first 2 to 3 stages, reaching 45 rpm. When the temperature rises to 120℃~130℃, the speed is gradually reduced when the top bolt is raised to clean and turn the rubber compound. Finally, the rotor speed of the A-mixing internal mixer 41 is 35 r / min ~ 40 r / min, and the internal mixing discharge temperature is between 165℃~175℃. When processing B rubber compound, the rotor speed of the B rubber mixing mill 51 is 20r / min~30r / min, the top bolt pressure of the B rubber mixing mill 51 is 4Kgf~5Kgf, and the mixing discharge temperature is between 80℃~90℃. The filter screens of the A compound rubber filtration device 43 and the B compound rubber filtration device 53 used for filtering A compound rubber and B compound rubber respectively are both between 100-150 mesh, which can further improve the dispersion grade of the compound rubber and the smoothness of the rubber strip surface, improve the product qualification rate and the stability of the extrusion process. When rubber A is processed into strips using an A-type rubber mixing mill or rubber B is processed into strips using a B-type rubber mixing mill, rapid cutting, turning, and stacking operations must be performed to allow the compound to cool down quickly, thereby increasing the Mooney viscosity of the compound and further improving the dispersion of carbon black and raw rubber in the compound.

[0025] In summary, before processing low-hardness sponge rubber, carbon black and oil softener are thoroughly impregnated together through static adsorption and dynamic stirring. This results in excellent carbon black dispersion in the processed low-hardness sponge compound, eliminating clumping and ensuring proper dispersion. During extrusion, the surface of the sponge rubber sealing strip forms a smooth skin, leading to a high pass rate and low scrap rate. This significantly reduces production costs for enterprises and improves efficiency and capacity.

[0026] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A low-hardness sponge rubber compounding production process, comprising the following steps: S1, A rubber compounding: First, the raw materials required for preparing A rubber compound are mixed according to the raw material ratio and addition order. After mixing, the rubber is discharged, cooled and filtered to obtain A rubber compound material. S2 and B rubber compounding: The A rubber compound in S1 is mixed with the raw materials required for preparing B rubber compound according to the raw material ratio and addition order until the A rubber compound and the raw materials required for preparing B rubber compound are fully mixed and then discharged, cooled and filtered to obtain the B rubber compound. S3. Cooling and maturation: The B compound material filtered in S2 is allowed to stand and cool down. The feature is that, in step S1, before mixing rubber A, the carbon black and oil softener required for preparing rubber A are pretreated, and the pretreatment includes the following steps: S01. Material preparation: Carbon black and oil softener are weighed multiple times. Each quantitative weighing of carbon black is divided according to the total weight of carbon black required and the number of times it is laid. Each quantitative weighing of oil softener is also divided according to the total weight of oil softener required and the number of times it is sprayed. S02, Static adsorption treatment: The carbon black weighed in S01 is laid layer by layer. The oil softener weighed in S01 is evenly sprayed on the surface of each layer of carbon black. After each oil softener is sprayed onto the surface of carbon black, it is left to stand for a set time so that the oil softener can be completely soaked into the carbon black. S03, Dynamic stirring treatment: The carbon black impregnated with oil softener in S02 is thoroughly stirred and mixed and then allowed to stand and cool. Heating is performed during both the static adsorption process in step S02 and the dynamic stirring process in step S03.

2. The low-hardness sponge rubber compounding production process according to claim 1, characterized in that, In step S02, the carbon black is laid 3-5 times, and the set standing time for each step in step S02 is 5-10 minutes.

3. The low-hardness sponge rubber compounding production process according to claim 1, characterized in that, The heating temperature during both the static adsorption process in step S02 and the dynamic stirring process in step S03 is 60℃~80℃.

4. The low-hardness sponge rubber compounding production process according to claim 1 or 2, characterized in that, In step S03, the stirring speed gradually increases from slow to fast, and the stirring speed is 60 r / min to 100 r / min, with a standing time of 1 h to 2 h.

5. The low-hardness sponge rubber compounding production process according to claim 4, characterized in that, In step S1, the mixing of rubber A includes internal mixing and open mixing of rubber A. The discharge temperature of internal mixing of rubber A is 165℃~175℃.

6. The low-hardness sponge rubber compounding production process according to claim 5, characterized in that, In step S2, the mixing of B rubber compound includes B rubber internal mixing and B rubber open mixing. The discharge temperature of B rubber internal mixing is 80℃~90℃.

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