A method for improving the testing efficiency of a Mooney machine

Abstract

The present invention relates to a method for improving the test efficiency of a Mooney machine. The conditions for Mooney scorch test and Mooney viscosity test on the Mooney machine are both under the condition of increasing the rotor at 120±1°C. Compared with the prior art, the present invention breaks through the traditional thinking limitation, reduces the switching between the large rotor and the small rotor, reduces the heating and cooling process of the test, and improves the utilization rate of the test equipment.

Description

Technical Field

[0001] The present invention relates to the field of rubber, and particularly to a method for improving the test efficiency of a Mooney machine. Background Art

[0002] In the field of rubber, especially in the tire industry, a large number of Mooney viscosity and Mooney scorch tests are required.

[0003] Mooney viscosity is an important parameter in the rubber processing process. It refers to the torque exerted by the rubber on the rotation of the rotor of the viscometer under certain experimental conditions when the rotor rotates in a cylindrical cavity filled with rubber. The Mooney viscosity of the rubber is represented by the reaction torque of the rubber on the rotation of the rotor of the viscometer, and the unit is Mooney viscosity.

[0004] Scorch is the phenomenon of early vulcanization of unvulcanized rubber in the process, that is, the cross-linking of linear molecules begins to occur. The speed of early vulcanization is measured by the scorch time. Due to the heat accumulation effect of rubber, the actual scorch time includes two parts: the operating scorch time and the remaining scorch time. The operating scorch time refers to the scorch time consumed due to the heat accumulation effect during the rubber processing, which depends on the processing conditions, such as rubber mixing, warming, calendering, extrusion and other process conditions. The remaining scorch time refers to the time that the rubber compound remains fluid in the hot mold.

[0005] Mooney viscosity and Mooney scorch tests are generally carried out using a Mooney machine. According to the national standard GB / T1233-92, a large rotor with a diameter of 38.10±0.03mm is generally used for the Mooney scorch test. When testing high-viscosity rubber compounds, a small rotor with a diameter of 30.48±0.03mm is allowed to be used. The scorch test temperature is generally 120±1°C. If there are special needs, other test temperatures can be used. Mooney viscosity tests are generally carried out at 100±1°C, and a large rotor with a diameter of 38.10±0.03mm is generally used for the test. When testing high-viscosity rubber compounds, a small rotor with a diameter of 30.48±0.03mm is allowed to be used. Mooney scorch and Mooney viscosity tests require the use of two types of rotors and two test temperatures.

[0006] To avoid the automatic interruption of the test due to excessive Mooney viscosity during the Mooney viscosity test of masterbatch, both a small rotor and a large rotor need to be used simultaneously in the existing test process. It is easy for testers to use the wrong rotor when switching codes. Moreover, the temperature for this Mooney viscosity test is 100 ± 1°C, while the general test temperature for Mooney scorch is 120 ± 1°C. Temperature increase and decrease operations are required when switching between Mooney viscosity and Mooney scorch tests. The temperature increase and stabilization process takes 15 minutes, and the temperature decrease and stabilization process takes 30 minutes. That is, more than 45 minutes will be lost for each switch. In the rubber field, especially in the tire industry, a large number of Mooney scorch and Mooney viscosity tests need to be carried out, but generally, the working time of a Mooney machine cannot be fully occupied by Mooney scorch tests. Separately reserving a Mooney machine for Mooney scorch tests or frequently performing temperature increase and decrease operations will both reduce the test efficiency of the Mooney machine. Summary of the Invention

[0007] The purpose of the present invention is to solve the above technical problems and provide a method for improving the test efficiency of a Mooney machine by reducing the switching between the large rotor and the small rotor and reducing the temperature increase and decrease process of the test.

[0008] The purpose of the present invention can be achieved through the following technical solutions: A method for improving the test efficiency of a Mooney machine, where the conditions for Mooney scorch test and Mooney viscosity test on the Mooney machine are both under the condition of using a large rotor at 120 ± 1°C.

[0009] Furthermore, use a large rotor at 120 ± 1°C for Mooney viscosity test instead of using a small rotor at 100 ± 1°C for Mooney viscosity test.

[0010] Furthermore, the Mooney machine is a commonly commercially available Mooney machine.

[0011] Furthermore, the process of Mooney scorch test and Mooney viscosity test is as follows:

[0012] (4) Preheat the mold cavity and the large rotor to the test temperature and make it reach a stable state;

[0013] (5) Open the mold cavity, insert the rotor rod into the central hole of the specimen with holes, place the large rotor in the lower mold, then accurately place another specimen on the large rotor, and quickly seal the mold cavity to preheat the specimen;

[0014] (6) After the specimen reaches the preheating time, immediately rotate the large rotor and record the reading.

[0015] In step (1), the stable state is: when the rotor of the Mooney viscometer rotates without load, the Mooney value reading on the recorder or dial is within the range of ±0.5.

[0016] In step (2), the preheating time is 1 - 2 min.

[0017] Further, a piece of glassine paper is lined between the specimen and the die cavity, or a release agent is coated thereon.

[0018] The diameter of the large rotor is 38.10 ± 0.03 mm.

[0019] The specimen to be tested is a rubber compound for tires, which can be a high-viscosity rubber compound or a low-viscosity rubber compound.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] The present invention breaks through the limitation of conventional thinking, and uses a large rotor at 120 ± 1 °C to conduct Mooney viscosity test instead of using a small rotor at 100 ± 1 °C. After using a large rotor at 120 ± 1 °C to conduct Mooney viscosity test instead of using a small rotor at 100 ± 1 °C, Mooney scorch test and Mooney viscosity test can be simultaneously conducted on a single Mooney machine without temperature rise and fall, reducing the temperature rise and fall process of the test, and at the same time reducing the switching between the large rotor and the small rotor, improving the utilization rate of the test equipment. Specific embodiments

[0022] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0023] Embodiment 1

[0024] A method for improving the test efficiency of a Mooney machine, which simultaneously conducts Mooney scorch test and Mooney viscosity test on a commercially available Mooney machine under the condition of a large rotor at 120 ± 1 °C. Specifically, that is, using a large rotor at 120 ± 1 °C to conduct Mooney viscosity test instead of using a small rotor at 100 ± 1 °C.

[0025] The processes of the Mooney scorch test and the Mooney viscosity test are carried out with reference to the provisions of the national standard GB / T 1233-92:

[0026] (1) Preheat the die cavity and the large rotor to the test temperature and make them reach a stable state; when the Mooney viscometer rotates with the rotor unloaded, the Mooney value reading on the recorder or the dial is within the range of ±0.5. The diameter of the large rotor is 38.10 ± 0.03 mm.

[0027] (2) Open the die cavity, insert the rotor rod into the central hole of the specimen with holes, and place the large rotor in the lower die, then accurately place another specimen on the large rotor, and quickly seal the die cavity to preheat the specimen; the preheating time is 1 min. A piece of glassine paper can be lined between the specimen and the die cavity, or a release agent can be coated thereon.

[0028] (3) After the specimen reaches the preheating time, immediately rotate the large rotor and continuously record the Mooney value with a recorder, or continuously observe the indicated value on the dial within 30 seconds before the specified time, and take the lowest Mooney value during this period as the viscosity of the specimen, with a reading accuracy of 0.5 Mooney value.

[0029] The specimen to be tested is a rubber compound for tires, which can be a high-viscosity rubber compound or a low-viscosity rubber compound.

[0030] In this embodiment, the rubber compounds of the materials are as follows:

[0031] Table 1, Formulations of Rubber Compounds for Each Generation of Tests

[0032]

[0033]

[0034] Table 2, Mooney Viscosity Test Standards and Conditions for Masterbatches in Example 1:

[0035] L.R represents the large rotor with a diameter of 38.10 ± 0.03 mm

[0036]

[0037] Comparative Example 1

[0038] To avoid automatic interruption of the test due to too high Mooney value during the Mooney viscosity test of the masterbatch, both a small rotor and a large rotor need to be used simultaneously in the existing test process. The test is carried out in accordance with the provisions of the national standard GB / T 1233-92, and the test results are shown in Table 3 below:

[0039] Table 3, Mooney Viscosity Test Standards and Conditions for Each Masterbatch

[0040] L.R represents the large rotor with a diameter of 38.10 ± 0.03 mm; S.R represents the small rotor with a diameter of 30.48 ± 0.03 mm

[0041]

[0042]

[0043] After using a large rotor at 120 ± 1 °C for Mooney viscosity test instead of using a small rotor at 100 ± 1 °C for Mooney viscosity test, the test standards and conditions for the masterbatch that originally required a small rotor for Mooney viscosity test in Table 3 are shown in Table 2. It can be seen that the masterbatch that originally required a small rotor for Mooney viscosity test at 100 ± 1 °C can be tested using a large rotor at 120 ± 1 °C.

[0044] It avoids the situation of using the wrong rotor during the switching process of the large and small rotors. Moreover, it avoids the switching temperature, saving more than 45 minutes for each switching, which greatly improves the test efficiency.

[0045] Taking A as an example, tests were carried out on the No. 1 Mooney viscometer that only measures Mooney scorch and the No. 2 Mooney viscometer that measures both Mooney viscosity and Mooney scorch. Six samples of the same batch were tested respectively, and the t5 results are as follows.

[0046]

[0047]

[0048] It can be seen that measuring both Mooney viscosity and Mooney scorch will not have a great impact on the scorch results.

[0049] In summary, it can be seen that after using a 120±1°C large rotor to conduct Mooney viscosity tests instead of using a 100±1°C small rotor for Mooney viscosity tests, Mooney scorch tests and Mooney viscosity tests can be carried out simultaneously on one Mooney machine without the need for temperature rise and fall. The temperature rise and fall process of the test is reduced, and at the same time, the switching between the large rotor and the small rotor can be reduced, improving the utilization rate of the test equipment.

[0050] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent replacements or changes, and should be covered by the protection scope of the present invention.

Claims

1. A method for improving the test efficiency of a Mooney machine. The conditions for Mooney scorch test and Mooney viscosity test on the Mooney machine are both under the condition of increasing the rotor at 120 ± 1 °C. The processes of the Mooney scorch test and the Mooney viscosity test are as follows: Preheat the mold cavity and the large rotor to the test temperature and make it reach a stable state. The stable state is that when the rotor of the Mooney viscometer rotates without load, the Mooney value reading on the recorder or dial is within the range of ±0.

5. Open the mold cavity, insert the rotor rod into the central hole of the specimen with holes, place the large rotor in the lower mold, then accurately place another specimen on the large rotor, and quickly seal the mold cavity to preheat the specimen. The diameter of the large rotor is 38.10 ± 0.03 mm. After the specimen reaches the preheating time, immediately rotate the large rotor and record the reading. The specimen to be tested is rubber compound for tires. Among them, Use the Mooney viscosity test with the large rotor at 120 ± 1 °C instead of using the Mooney viscosity test with the small rotor at 100 ± 1 °C.

2. The method for improving the test efficiency of a Mooney machine according to claim 1, characterized in that, The Mooney machine is a common commercially available Mooney machine.

3. A method for improving the test efficiency of a Mooney machine according to claim 1, characterized in that, In step (2), the preheating time is 1 - 2 min.

4. A method for improving the test efficiency of a Mooney machine according to claim 1, characterized in that, Line a piece of glassine paper or apply a release agent between the specimen and the mold cavity.

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