Rubber additive
Vacuum Dryer is a drying equipment designed for the characteristics of rubber additives (such as accelerators, anti-aging agents, vulcanizing agents, etc.). Its core principle is to use a vacuum environment to reduce the boiling point of materials, combined with heating and mechanical transmission to achieve efficient dehydration or solvent removal, while avoiding oxidation, decomposition or deterioration of materials due to high temperature.
1、 Core principle: Low temperature drying under vacuum environment
Vacuum reduces boiling point
In a vacuum state, the internal air pressure of the dryer is lower than the standard atmospheric pressure (1atm). According to physical properties, the boiling point of a liquid decreases with decreasing air pressure (for example, water has a boiling point of 100 ℃ at standard atmospheric pressure and only about 20 ℃ at 0.02 atm).
Rubber additives usually contain water or organic solvents. In a vacuum environment, these liquids can vaporize at lower temperatures (usually 50-100 ℃, much lower than the material's thermal decomposition temperature) to avoid high temperature damage to the active ingredients of the additives.
Heating provides vaporization energy
The dryer transfers heat to the material through jacket heating (hot water, steam, or thermal oil), direct heating by blades/rake teeth, etc., to meet the energy required for liquid vaporization. Due to the decrease in boiling point under vacuum, the heating temperature does not need to be too high, which can efficiently dry and protect thermosensitive rubber additives.
Discharge of water vapor/solvent
The steam generated by vaporization (water or solvent vapor) is promptly extracted by a vacuum system (vacuum pump, condenser, etc.):
Steam is first cooled by a condenser and condensed into liquid for recycling (if it is an organic solvent, it can reduce waste and pollution);
Non condensable gases are expelled by a vacuum pump to maintain the system's vacuum level.
2、 Coordination between structure and workflow
Rubber additive vacuum dryer is usually a horizontal or vertical structure with built-in mixing devices (such as blades and rake teeth). The working process is as follows:
Feed: Add wet rubber additives (usually with a moisture content of 10% -30%) to the dryer cylinder.
Vacuum pumping: Close the feeding port, start the vacuum pump, and make the vacuum degree inside the cylinder reach the set value (such as -0.08~-0.095MPa).
Heating and stirring:
The jacket or built-in heating element starts heating, and the material temperature rises to the target value (such as 60 ℃);
The stirring device continues to rotate, dispersing and flipping the material, increasing the heating surface area, avoiding local overheating or agglomeration, and ensuring uniform drying.
Vaporization and exhaust: The moisture/solvent in the material vaporizes under vacuum and heating, and the steam is liquefied and recovered through a condenser. The remaining gas is discharged by a vacuum pump.
Discharge: After drying is completed (the moisture content of the material drops to 0.1% -1%), stop heating and vacuum, break the vacuum, open the discharge port, and discharge the dry material through the stirring device.
3、 Special design for rubber additives
Anti oxidation protection
Vacuum environment isolates air (especially oxygen) to prevent rubber additives (such as anti-aging agents and vulcanizing agents) from becoming ineffective or discolored due to oxidation during the drying process.
Adapt to viscous/heat sensitive materials
The rubber additive is in the form of paste, powder, or particles, and the stirring device (such as a spiral blade) can adapt to its viscosity to avoid sticking to the wall; Low temperature drying protects the chemical stability of additives (such as accelerators M, DM, etc., which are prone to decomposition when exposed to high temperatures).
Sealing and Environmental Protection
The entire process is sealed, with no dust flying (rubber additives are mostly fine powder, reducing the risk of operator contact), and the organic solvent vapor can be recovered, which meets environmental protection requirements.
4、 Summary of Advantages
Low temperature drying: protects the active ingredients of rubber additives, avoiding high-temperature decomposition or deterioration;
Efficient and energy-saving: Accelerated vaporization in a vacuum environment, short drying time (usually 2-6 hours), and lower energy consumption than hot air drying;
Environmental safety: Closed operation, reducing dust and solvent volatilization, in compliance with chemical production standards.
Jinkebotong Environmental Protection Technology (Jiangsu) Co., Ltd
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