A vulcanization process for peroxide-vulcanized articles

Abstract

The application discloses a vulcanization process for peroxide vulcanized products, and steps of the process comprise: S1, providing a vulcanization tank, and connecting the vulcanization tank with a vacuum pump; S2, adding sufficient water at the bottom of the vulcanization tank, and placing a peroxide product to be vulcanized into the vulcanization tank, and covering a cover of the vulcanization tank to form a closed space; S3, vacuumizing at normal temperature to reduce the boiling point of water in the vulcanization tank until water starts to evaporate at normal temperature and a target pressure; S4, maintaining the target pressure, that is, at this time, the volume of water evaporated into water vapor per unit time is equal to the volume of water vapor extracted by the vacuum pump; S5, stopping the vacuumizing after continuously vacuumizing for a target time; S6, heating the vulcanization tank to vulcanize; and S7, after the vulcanization is completed, stopping the heating, releasing the gas pressure in the tank, opening the vulcanization tank, and taking out the product. The vulcanization process is ingenious and effective, and greatly reduces the problems that energy consumption is large in a traditional peroxide vulcanization process and oxygen cannot be completely discharged.

Description

Technical Field

[0001] This invention relates to the field of vulcanization technology, and in particular to a vulcanization process for peroxide vulcanized products. Background Technology

[0002] Rubber has a wide range of applications in daily life. In rubber production, manufacturers add peroxides to rubber to improve the high temperature resistance and aging resistance of the products, depending on the needs of different customers.

[0003] When placing uncured but already formed peroxide products into a vulcanizing tank for vulcanization, the vulcanizing tank needs to be evacuated to greatly reduce the oxygen concentration in the vulcanizing tank. This prevents the peroxides from reacting with oxygen during the vulcanization process, causing the peroxides to decompose and leading to a decline in the quality of the final product.

[0004] Existing methods for deoxygenation in the vulcanization process of peroxide products generally achieve the following:

[0005] 1. Before the vulcanization heating, nitrogen is generated by a nitrogen generator and injected into the vulcanization tank. Oxygen is then expelled through an exhaust port inside the tank. However, on the one hand, the cost of the nitrogen generator is very high, with the purchase cost of one unit reaching tens of thousands of yuan; on the other hand, the method of expelling oxygen by injecting gas often results in dead corners inside the tank, where oxygen remains under the pressure of nitrogen, ultimately causing the reaction between peroxides and oxygen during the vulcanization process.

[0006] 2. Steam is generated by a boiler and injected into a vulcanizing tank. Oxygen is squeezed out through an exhaust port inside the tank. However, there are dead corners inside the tank. Oxygen will remain in the corners of the tank under the pressure of steam, which will eventually cause the reaction between peroxide and oxygen during the vulcanization process.

[0007] 3. Oxygen can be directly extracted using a vacuum pump for deoxygenation. However, because the required oxygen concentration is extremely low, achieving the required oxygen concentration through vacuuming would take a very long time and be quite costly.

[0008] In view of this, the applicant has invented a low-cost vulcanization process for peroxide vulcanized products that can effectively achieve deoxygenation. Summary of the Invention

[0009] In order to overcome the shortcomings of the prior art, the present invention provides a low-cost vulcanization process for peroxide vulcanized products that can effectively achieve deoxygenation.

[0010] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0011] A vulcanization process for peroxide-cured products includes the following steps:

[0012] S1: Provide a vulcanizing tank and connect the vulcanizing tank to a vacuum pump;

[0013] S2: Add sufficient water to the bottom of the vulcanizing tank, and put the peroxide product to be vulcanized into the vulcanizing tank, and cover the vulcanizing tank to form a sealed space;

[0014] S3: Vacuum is drawn at room temperature to lower the boiling point of water in the vulcanizing tank until the water begins to evaporate at room temperature and target pressure;

[0015] S4: Maintain the target pressure to form a stable negative pressure in the vulcanizing tank, that is, the volume of water evaporated into water vapor per unit time is equal to the volume of water vapor extracted by the vacuum pump, so as to continuously extract oxygen from the vulcanizing tank while restoring the air pressure using the continuously evaporated water vapor. During this period, ensure that the water in the vulcanizing tank is not pumped dry.

[0016] S5: Stop pumping after the target pumping time has elapsed;

[0017] S6: Heat the vulcanizing tank for vulcanization;

[0018] S7: After vulcanization is complete, stop heating, release the pressure inside the tank, open the vulcanization tank and remove the product.

[0019] As a further improvement, in step S2, a support frame is provided in the vulcanizing tank, on which the peroxide product to be vulcanized is placed, while ensuring that the support frame is above the water surface.

[0020] As a further improvement, in step S2, the peroxide product to be sulfurized is completely immersed in water.

[0021] As a further improvement, sodium chloride or barium chloride is added to the water to suspend the peroxide product to be sulfided in the water.

[0022] As a further improvement, the vacuum pump is a water ring vacuum pump.

[0023] As a further improvement, the range of the target pressure is:

[0024] As a further improvement, the range of the target concentration is:

[0025] Compared with the prior art, the beneficial effects that this invention can achieve are:

[0026] 1. This invention discloses a peroxide-cured product curing process. By adding sufficient water to the bottom of the curing tank as a working fluid and using a vacuum pump to create a vacuum, the boiling point of water decreases under negative pressure. This allows water to boil at room temperature, generating a large amount of water vapor. The vacuum pump then extracts this water vapor, continuously removing oxygen. Simultaneously, as water vapor is generated, the pressure inside the curing tank increases, which helps maintain the low-energy-consumption operating pressure of the vacuum pump. Microscopically, when a stable negative pressure is formed in the curing tank, the volume of water vapor evaporated per unit time equals the volume of water vapor extracted by the vacuum pump. This allows for the continuous extraction of oxygen from the curing tank while the continuously evaporating water vapor restores the pressure. During this process, as long as the water in the curing tank is not completely drained, oxygen can be continuously extracted, achieving an extremely low oxygen concentration with low energy consumption. The overall curing process is ingenious and effective, greatly reducing the problems of high energy consumption and incomplete oxygen removal in traditional peroxide curing processes. Detailed Implementation

[0027] To make the technical means, creative features, and achieved objectives and effects of this invention easier to understand, the invention is further described below with reference to specific embodiments. However, the following embodiments are merely preferred embodiments of this invention and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments described herein without creative effort are all within the protection scope of this invention. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods, and the materials and reagents used in the following embodiments are commercially available unless otherwise specified.

[0028] This invention provides a vulcanization process for peroxide-cured products, comprising the following steps:

[0029] S1: A vulcanizing tank is provided, and the vulcanizing tank is connected to a vacuum pump. An exhaust pipe is provided extending inward from the inner wall of the vulcanizing tank. Several pressure sensors and temperature sensors are provided on the inner wall of the vulcanizing tank for sensing the pressure and temperature inside the tank.

[0030] S2: Add sufficient water to the bottom of the vulcanizing tank, and put the peroxide product to be vulcanized into the vulcanizing tank, and cover the vulcanizing tank to form a sealed space;

[0031] S3: Vacuum is drawn at room temperature to lower the boiling point of water in the vulcanizing tank until the water begins to evaporate at room temperature and target pressure;

[0032] S4: Maintain the target pressure to form a stable negative pressure in the vulcanizing tank, that is, the volume of water evaporated into water vapor per unit time is equal to the volume of water vapor extracted by the vacuum pump, so as to continuously extract oxygen from the vulcanizing tank while restoring the air pressure using the continuously evaporated water vapor. The air pressure in the tank is detected in real time by the pressure sensor mentioned above. When the air pressure is observed to be stable and unchanged, it can be determined that the continuous oxygen removal stage has been entered.

[0033] In practice, depending on the size of the tank, the power of the vacuum pump, and the product to be vulcanized, after selecting the tank and vacuum pump, the vulcanization situation of different products under different evacuation times can be determined through multiple experiments in the early stage. The required continuous negative pressure time before vulcanization of each product can be determined to determine the target evacuation time. During this period, it is ensured that the water in the vulcanization tank will not be pumped out.

[0034] S5: Stop pumping after the target pumping time has elapsed;

[0035] S6: Heat the vulcanizing tank for vulcanization;

[0036] S7: After vulcanization is complete, stop heating, release the pressure inside the tank, open the vulcanization tank and remove the product.

[0037] The integrated vulcanization process utilizes the characteristic that water's boiling point decreases under negative pressure. This allows water to boil at room temperature, generating a large amount of steam. The vacuum pump then extracts this steam, continuously removing oxygen. Simultaneously, the pressure inside the vulcanization tank rises with the steam, helping to maintain the vacuum pump's low-energy operating pressure. Microscopically, when a stable negative pressure is established in the vulcanization tank, the volume of water vapor evaporated per unit time equals the volume of steam extracted by the vacuum pump. This allows for continuous oxygen extraction while simultaneously restoring pressure using the continuously evaporating steam. During this process, ensuring the water inside the tank doesn't dry out is sufficient to effectively extract oxygen, achieving extremely low oxygen concentrations with low energy consumption. This ingenious and effective integrated vulcanization process significantly reduces the high energy consumption and incomplete oxygen removal problems of traditional peroxide vulcanization processes.

[0038] In this embodiment, in step S2, a support frame is provided in the vulcanizing tank. The support frame is used to place the peroxide product to be vulcanized, while ensuring that the support frame is above the water surface. This method can be applied to various horizontal or vertical vulcanizing tanks. It can also effectively target peroxide products that do not have high shape requirements and cannot be vulcanized in direct contact with water. By separating them from water, rapid heat conduction is achieved during the vulcanization heating process, thereby shortening the vulcanization time.

[0039] In another embodiment, in step S2, the peroxide product to be vulcanized is completely immersed in water. When the vulcanizing tank is a horizontal vulcanizing tank, a water tank and a heater need to be designed at the bottom of the horizontal vulcanizing tank. At the same time, a container is set in the tank to fill with sufficient water, and the product to be vulcanized is immersed in the water in the container. The water in the container is indirectly heated by the water in the water tank to form steam. As long as the pressure value is met, the water in the container will also reach the corresponding temperature value. When the vulcanizing tank is a vertical vulcanizing tank, a heating element is directly set at the bottom of the tank and sufficient water is filled to immerse the product to be vulcanized. This vulcanization method can be used for some irregularly shaped and relatively soft peroxide vulcanized products. The water provides a certain buoyancy, thereby avoiding the problem of deformation caused by placing the product directly on the support frame for vulcanization.

[0040] Furthermore, a specific gravity salt, such as sodium chloride or barium chloride, can be added to the water to change the water density, so that the peroxide product to be vulcanized can be completely suspended in the water, avoiding the inner wall of the vulcanizing tank from squeezing the product shape and thus affecting the molding effect after vulcanization.

[0041] In addition, in step S6, when the peroxide product to be vulcanized is completely immersed in water, after the air extraction is stopped, a heating element inside or at the bottom of the vulcanizing tank can be used to form a stable temperature and pressure inside the vulcanizing tank, thereby forming superheated water or supercritical water. The superheated water or supercritical water has a strong solubility to extract small molecules from the rubber, reduce the VCO content in the product to be vulcanized, and improve the quality of the vulcanized product.

[0042] In this embodiment, the vacuum pump is a water ring vacuum pump, which has low cost, large exhaust volume, and uses water as the working fluid. Therefore, it can effectively address the application scenario in the vulcanization process that requires the discharge of a large amount of water vapor, demonstrating ingenious application.

[0043] It should be further explained that, in this embodiment, depending on the size of the tank, the power of the vacuum pump, and the product, the final constant pressure value reached after evacuation will vary within a relatively large range. Generally, the smaller the tank, the greater the power of the vacuum pump, and the shorter the evacuation time, and vice versa. The correspondence between the gas pressure and the boiling point of water can be directly referenced from the saturated vapor pressure gauge of water.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A vulcanization process for peroxide-vulcanized articles, characterized in that: The method comprises the following steps: S1: providing a sulfurization tank, connecting the sulfurization tank with a vacuum pump; S2: adding sufficient water at the bottom of the sulfurization tank, and placing the peroxide product to be sulfurized into the sulfurization tank, and covering the cover of the sulfurization tank to form a closed space; S3: vacuumizing at normal temperature to reduce the boiling point of water in the sulfurization tank until the water starts to evaporate at normal temperature and target pressure; S4: maintaining the target pressure to form a stable negative pressure in the sulfurization tank, that is, at this time, the volume of water vapor evaporated per unit time is equal to the volume of water vapor pumped out by the vacuum pump, so as to continuously pump out oxygen in the sulfurization tank while recovering the air pressure by using the continuously evaporated water vapor, and during this period, it is ensured that the water in the sulfurization tank will not be pumped dry; S5: stopping the pumping after the target time; S6: heating the sulfurization tank for sulfurization; S7: stopping heating after the sulfurization is completed, releasing the air pressure in the tank, opening the sulfurization tank, and taking out the product.

2. The vulcanization process for peroxide-vulcanized articles according to claim 1, characterized by the fact that: In step S2, a support frame is arranged in the sulfurization tank, and the peroxide product to be sulfurized is placed on the support frame, and the support frame is ensured to be above the water surface.

3. The vulcanization process for peroxide-vulcanized articles according to claim 1, characterized in that: In step S2, the peroxide product to be sulfurized is completely immersed in water.

4. The vulcanization process for peroxide-vulcanized articles according to claim 3, characterized in that: Further, specific gravity salt is added to the water, so that the peroxide product to be sulfurized is suspended in the water.

5. The vulcanization process for peroxide-vulcanized articles according to claim 1, characterized in that: The vacuum pump is a water ring vacuum pump.