A rubber mixing method using an internal mixer

Abstract

This invention provides a rubber mixing method using an internal mixer. During the mixing process, the top plug of the internal mixer is set to a floating state. In this floating state, oil is added to the mixing chamber of the internal mixer to mix with the rubber compound. The floating of the top plug means that, without external pressure, the top plug rests solely on the mixed rubber compound by its own weight, moving up and down as it comes into contact with the rubber compound during mixing. This method of rubber mixing using an internal mixer allows for the simultaneous addition of oil while the top plug is floating, eliminating the need to raise the top plug, wait for oil to be added, and then press the top plug down again. This saves time spent on separate oil addition, shortens the mixing cycle, and improves production efficiency.

Description

Technical Field

[0001] This invention relates to the field of rubber technology, and more specifically to a rubber mixing method using an internal mixer. Background Technology

[0002] The internal mixer mainly consists of an upper top plug, a mixing chamber, a rotor, and a lower top plug. The mixing process in an internal mixer involves the addition of oil. Traditionally, the upper top plug is raised to its designated position before the oil is added, followed by the pressing down of the upper top plug. If the formula contains a large amount of oil, the oiling time will be long, thus extending the overall mixing cycle. The mixing time under the pressed top plug condition is generally considered the effective mixing time. In the traditional oiling process, the upper top plug is in its designated position, so the time spent adding oil is considered ineffective mixing time. The BB620 model internal mixer can be set to a floating upper top plug condition. A floating upper top plug means that the upper top plug, without external pressure, rests on the rubber compound under its own weight, moving up and down as it comes into contact with the compound during mixing. The mixing time under the floating upper top plug condition can be considered the effective mixing time under the pressed top plug condition. Therefore, how to shorten the overall mixing cycle of the internal mixer requires further exploration by technical personnel. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a rubber mixing method using an internal mixer to solve the technical problem of long rubber mixing time in related technologies.

[0004] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: a rubber mixing method using an internal mixer is provided, wherein the top plug of the internal mixer is set to have a floating state during the rubber mixing process. When the top plug is floating, oil is added to the mixing chamber of the internal mixer and mixed with the rubber compound. The floating of the top plug means that the top plug is pressed on the mixed rubber by its own weight without external pressure, and moves up and down as it comes into contact with the rubber compound during the mixing process.

[0005] Furthermore, the floating time of the top bolt is 20-40 seconds.

[0006] Furthermore, the floating time of the top bolt is 30 seconds.

[0007] Furthermore, the top bolt is pressed three times during the rubber mixing process, with the second pressing of the top bolt being to keep the top bolt floating.

[0008] Furthermore, after adding the rubber compound and other minor ingredients into the mixing chamber, the internal mixer is started. The first pressing of the top bolt is performed, and after holding for 25-45 seconds, the top bolt is raised to its final position. The second pressing of the top bolt is then performed, and the top bolt floats for 20-40 seconds. While the top bolt is floating, oil is added. After the top bolt floats again, the top bolt is raised to its final position. The third pressing of the top bolt is then performed, and after holding for 15-25 seconds, the top bolt is raised to its final position, and mixing is stopped.

[0009] Furthermore, the pressure of the first pressing of the top bolt is 0.5-0.6 MPa, and the pressure of the third pressing of the top bolt is 0.5-0.6 MPa.

[0010] Furthermore, the internal mixer has two oil inlets, and dual motors are used to add oil into the mixing chamber of the internal mixer from the oil inlets.

[0011] Furthermore, the injection pressure when the oil is added from the oil inlet is 0.5-3 MPa.

[0012] Furthermore, the oil is an aromatic oil.

[0013] Furthermore, by weight, the rubber compound includes: 50-60 parts natural rubber and 40-50 parts butadiene rubber; the minor components include: 40-50 parts carbon black, 2-4 parts zinc oxide, 1-3 parts stearic acid, 3-7 parts antioxidant, and 2-5 parts resin.

[0014] Furthermore, by weight, the rubber compound includes: 50 parts natural rubber and 50 parts butadiene rubber; the minor components include: 46 parts carbon black, 3 parts zinc oxide, 2 parts stearic acid, 5 parts antioxidant, and 3 parts resin.

[0015] Furthermore, the oil is an aromatic oil, and the amount of aromatic oil added is 4-6 parts.

[0016] Beneficial effects:

[0017] 1. The rubber mixing method of the present invention using an internal mixer allows for the simultaneous addition of oil while the top plug is floating, saving 20-40 seconds of separate oiling time, shortening the mixing cycle, and improving production efficiency.

[0018] 2. The pressure of the top bolt in the rubber mixing method using an internal mixer of the present invention is 0.5-0.6 MPa. Within this pressure range, the rubber compound and the minor ingredients are fully mixed in the mixing chamber. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the internal mixer of the present invention.

[0020] The above figures include the following reference numerals:

[0021] 1. Top bolt; 2. Rotor; 3. Mixing chamber; a. The position of the top bolt when it is pressed down; b. The position of the top bolt when it is raised. Detailed Implementation

[0022] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0023] According to an embodiment of the present invention, a method for mixing rubber using an internal mixer is provided. Oil is added to the mixing chamber 3 of the internal mixer and mixed with the rubber compound while the top plug is floating. This method saves the time required for separate oil addition, shortens the mixing cycle, and improves production efficiency. Compared with the prior art, the mixing time of the internal mixer in this invention is shortened. "Top plug 1 floating" means that the top plug 1, without external pressure, is pressed onto the mixed rubber compound solely by its own weight, moving up and down as it comes into contact with the rubber compound during mixing. The mixing time with the top plug 1 floating can be considered the effective mixing time under the pressed plug state. The gravity applied to the mixed rubber compound under the floating top plug state is the weight of the top plug 1 itself. On the one hand, the mixed rubber compound can be effectively mixed; on the other hand, only its own weight is used in the floating top plug state, so oil can be added. If under the pressed top plug condition, the pressure is 0.5-0.6 MPa, and due to the higher internal pressure of the mixing chamber, oil is not easily added.

[0024] The floating time of the top plug is 20-40 seconds. Due to the difference in the weight of the oils in the formula, the oiling cycle can generally be completed within 10-20 seconds. Setting the floating time of the top plug to 20-40 seconds and performing the oiling action simultaneously ensures that the oiling action is completed within the set floating time, saving the time required for separate oiling and shortening the overall mixing cycle. Specifically, the floating time of the top plug is 30 seconds, ensuring that the oil is added completely while saving overall mixing time.

[0025] During rubber mixing, the top bolt is pressed down three times. The second pressing down is to keep the top bolt floating. The top bolt cannot be in a constantly pressed-down or constantly raised state during rubber mixing. This method involves pressing the top bolt down three times during the mixing process. During the second pressing down, no external pressure is applied; the top bolt remains floating solely due to its own weight. Figure 1 As shown, when the top bolt is pressed down, the top bolt is at position a, which is the uppermost position of the top bolt when the top bolt is pressed down; when the top bolt is raised, the top bolt is at position b, which is the uppermost position of the top bolt when the top bolt is raised.

[0026] Specifically, after adding rubber compound and minor ingredients into mixing chamber 3, the internal mixer is started. The first pressing of the top bolt is performed, held for 25-45 seconds, then the top bolt is raised to its final position. The second pressing of the top bolt is then performed, with the top bolt floating for 20-40 seconds. Simultaneously, oil is added during this floating period. After the top bolt floats again, the top bolt is raised to its final position, and the third pressing of the top bolt is performed, held for 15-25 seconds, then the top bolt is raised to its final position, stopping the mixing process. After adding rubber compound and minor ingredients, the first pressing of the top bolt is performed. Under pressure, the rubber compound and minor ingredients are mixed by rotor 2. After mixing for 25-45 seconds, the top bolt floats for 20-40 seconds, simultaneously adding oil during this floating period. After adding oil, the top bolt is raised to its final position, and immediately the third pressing of the top bolt is performed. The entire pressing and raising of the top bolt, along with the rotation of rotor 2 and the rubber compound, completes the entire mixing process, ensuring thorough mixing of the rubber compound.

[0027] The pressure of the first pressing of the top bolt is 0.5-0.6 MPa, and the pressure of the third pressing of the top bolt is also 0.5-0.6 MPa. In this scheme, the pressures of the first and third pressing of the top bolt are adjusted to 0.5-0.6 MPa respectively. To further improve the mixing effect of the rubber compound, the pressure of the first pressing of the top bolt is 0.5 MPa, and the pressure of the third pressing of the top bolt is 0.6 MPa.

[0028] The injection pressure when adding oil from the oil inlet is 0.5-3 MPa.

[0029] By weight, the rubber compound includes: 50-60 parts natural rubber and 40-50 parts butadiene rubber; the minor components include: 40-50 parts carbon black, 2-4 parts zinc oxide, 1-3 parts stearic acid, 3-7 parts antioxidant, and 2-5 parts resin; the oil is aromatic oil, and the amount of aromatic oil added is 4-6 parts.

[0030] The following examples illustrate this point.

[0031] Example 1

[0032] Using a BB620 internal mixer, add 50 parts natural rubber, 50 parts butadiene rubber, 46 parts carbon black, 3 parts zinc oxide, 2 parts stearic acid, 5 parts antioxidant, and 3 parts resin to the mixing chamber. Start the mixer and perform the first top-bolt press at 0.5 MPa. Hold for 25 seconds, then raise the top bolt to its final position. Perform the second top-bolt press, allowing the top bolt to float for 30 seconds. Simultaneously, add 5.5 parts aromatic oil through the oil inlet at a pressure of 2 MPa. After the top bolt floats again, raise it to its final position and perform the third top-bolt press at 0.6 MPa. Hold for 25 seconds, then raise the top bolt to its final position to stop mixing. Open the discharge gate to discharge the material.

[0033] Example 2

[0034] Using a BB620 internal mixer, add 60 parts natural rubber, 40 parts butadiene rubber, 40 parts carbon black, 2 parts zinc oxide, 1 part stearic acid, 3 parts antioxidant, and 2 parts resin to the mixing chamber. Start the mixer and perform the first top-bolt press at 0.5 MPa. Hold for 45 seconds, then raise the top bolt to its final position. Perform the second top-bolt press, allowing the top bolt to float for 20 seconds. Simultaneously, add 4 parts aromatic oil through the oil inlet at a pressure of 0.5 MPa. After the top bolt floats again, raise it to its final position and perform the third top-bolt press at 0.5 MPa. Hold for 15 seconds, then raise the top bolt to its final position to stop mixing. Open the discharge gate to discharge the material.

[0035] Example 3

[0036] Using a BB620 internal mixer, add 50 parts natural rubber, 50 parts butadiene rubber, 50 parts carbon black, 4 parts zinc oxide, 3 parts stearic acid, 7 parts antioxidant, and 5 parts resin to the mixing chamber. Start the mixer and perform the first top-bolt press at 0.6 MPa. Hold for 25 seconds, then raise the top bolt to its final position. Perform the second top-bolt press, allowing the top bolt to float for 45 seconds. Simultaneously, add 6 parts aromatic oil through the oil inlet at a pressure of 3 MPa. After the top bolt floats again, raise it to its final position and perform the third top-bolt press at 0.6 MPa. Hold for 20 seconds, then raise the top bolt to its final position to stop mixing. Open the discharge gate to discharge the material.

[0037] Comparative Example 1

[0038] Using a BB620 internal mixer, add 50 parts natural rubber, 50 parts butadiene rubber, 46 parts carbon black, 3 parts zinc oxide, 2 parts stearic acid, 5 parts antioxidant, and 3 parts resin to the mixing chamber. Then start the internal mixer and perform the first top-bolt press at a pressure of 0.5 MPa. After holding for 40 seconds, raise the top-bolt to the correct position and add 5.5 parts aromatic oil over 20 seconds. Then, press the top-bolt again at a pressure of 0.5 MPa and hold for 30 seconds. After raising the top-bolt to the correct position, perform the third top-bolt press at a pressure of 0.6 MPa and hold for 25 seconds. Then, raise the top-bolt to the correct position and stop mixing. Open the discharge gate to discharge the material.

[0039] The mixing times of Examples 1-3 and Comparative Example 1 were statistically analyzed, and the results are shown in Table 1.

[0040] Table 1. Statistics of mixing time for Examples 1-3 and Comparative Example 1

[0041] Example Time (s) Example 1 80 Example 2 80 Example 3 90 Comparative Example 1 115

[0042] The rubber mixing method of the present invention using an internal mixer allows for the simultaneous addition of oil while the top plug is floating, eliminating the need to raise the top plug, wait for the oil to be added, and then press the top plug back up. This saves time spent on separate oiling, shortens the mixing cycle, and improves production efficiency.

[0043] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for mixing rubber using an internal mixer, characterized in that, During the rubber mixing process, the top plug of the internal mixer is set to have a floating state. When the top plug is floating, the oil is added to the mixing chamber of the internal mixer and mixed with the rubber. The floating state of the top plug means that the top plug is pressed on the mixed rubber by its own weight without external pressure, and moves up and down as it comes into contact with the rubber during the mixing process. During the rubber mixing process, the top bolt is pressed down three times. The second pressing down of the top bolt is to keep the top bolt floating. After adding the rubber compound and other ingredients into the mixing chamber, start the internal mixer and perform the first pressing of the top bolt. Hold for 25-45 seconds, then raise the top bolt to its final position and perform the second pressing of the top bolt. Let the top bolt float for 20-40 seconds. While the top bolt is floating, add oil. After the top bolt has finished floating, raise the top bolt to its final position and perform the third pressing of the top bolt. Hold for 15-25 seconds, then raise the top bolt to its final position and stop mixing. The pressure of the first pressing of the top bolt is 0.5-0.6 MPa, and the pressure of the third pressing of the top bolt is 0.5-0.6 MPa.

2. The rubber mixing method using an internal mixer according to claim 1, characterized in that, The floating time of the upper bolt is 20-40 seconds.

3. The rubber mixing method using an internal mixer according to claim 2, characterized in that, The floating time of the upper bolt is 30 seconds.

4. The rubber mixing method using an internal mixer according to claim 1, characterized in that, The internal mixer has two oil inlets and uses dual motors to add oil into the mixing chamber of the internal mixer from the oil inlets.

5. The rubber mixing method using an internal mixer according to claim 4, characterized in that, The injection pressure when adding oil from the oil inlet is 0.5-3 MPa.

6. The rubber mixing method using an internal mixer according to claim 1, characterized in that, The oil is an aromatic oil.

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