What is a Rubber Mixer?
Internal mixers are mainly used for plasticizing and mixing rubber.
The internal mixer is a kind of machine that is equipped with a pair of rotors with a specific shape and rotates relative to each other. It is a machine that intermittently masticates and kneads polymer materials in a closed state with adjustable temperature and pressure. It is mainly composed of an internal mixing chamber, and rotors. It is composed of a rotor sealing device, feeding, and pressing device, unloading device, transmission device, and machine base.
The internal mixer is a kind of high-strength intermittent mixing equipment developed based on the open mixer. The rubber mixing process shows a series of characteristics that are superior to open mills, such as large mixing capacity, short time, and high production efficiency. Rubber mixing can better overcome dust flying, reduce the loss of compounding agents, and improve product quality and the working environment. The rubber mixer is safe and convenient to operate, reduces labor intensity, and is beneficial to realize mechanical and automatic operations. Therefore, the appearance of the internal mixer is an important achievement of rubber machinery, and it is still typical important equipment in plasticizing and mixing, and it is still developing and improving.
The Basic Structure of the Mixer:
The internal mixer is generally composed of an internal mixing chamber, two relatively rotating rotors, an upper top bolt, a lower top bolt, a temperature measurement system, a heating, and cooling system, an exhaust system, a safety device, a discharge device, and a recording device. The surface of the rotor has helical protruding ribs, and the number of protruding ribs is two, four, six, etc. The cross-sectional geometry of the rotor is triangular, cylindrical, or elliptical, and there are two types of tangential and meshing. The temperature measurement system is composed of thermocouples, which are mainly used to measure the temperature change in the mixing chamber during the mixing process. The heating and cooling system is mainly to control the temperature of the rotor and the wall surface of the mixing chamber.
Working Principle:
When the mixer is working, the two rotors rotate relative to each other. The material from the feeding port is clamped and brought into the roll gap to be squeezed and sheared by the rotor. Along the gap between the front and rear chamber walls and the rotor and back to the top of the nip.
During the flow around the rotor, the material is subjected to shearing and friction everywhere, so the temperature of the compound rises sharply. The viscosity decreases, the wettability of the rubber on the surface of the compounding agent is increased, and the rubber and the compounding agent surface are fully contacted. The batch of compounding agents passes through the gap between the rotor and the rotor. The rotor and the upper and lower top bolts, and the inner wall of the mixer together with the rubber compound. It is sheared and broken, surrounded by stretched and deformed rubber, and stabilized in a broken state. At the same time, the rib on the rotor makes the rubber material move along the axial direction of the rotor, which plays a role in stirring and mixing so that the compounding agent is evenly mixed in the rubber material. The compounding agent is repeatedly sheared and broken in this way, the rubber compound repeatedly deforms and recovers, and the rotor ridges are continuously stirred so that the compounding agent is uniformly dispersed in the compound and reaches a certain degree of dispersion.
Because the shearing action of the rubber compound is much larger than that of the open mixer during the mixing of the internal mixer, and the temperature of rubber mixing is high. The efficiency of the rubber mixture in the internal mixer is much higher than that of the open mixer. The main parameters are the rotational speed and speed ratio of the rotor. The rotor edge ratio and the inner wall gap of the mixing chamber. Production capacity and filling factor, unit pressure of the top bolt on the compound.
Internal Mixer Mixing Process:
Mixing is the process of mixing raw rubber or masticating raw rubber and compounding agents into mixed rubber with a rubber mixer, and it is the most important production process in rubber processing. Essentially, it is a process in which the compounding agent is uniformly dispersed in the raw rubber. The granular compounding agent is in the dispersed phase, and the raw rubber is in the continuous phase. Mixing can use an open mill, internal mixer, and screw continuous mixer. In essence, the rubber mixing process is a process in which the compounding agent is uniformly dispersed in the raw rubber. The granular compounding agent is in the dispersed phase, and the raw rubber is in the continuous phase. During the mixing process, the molecular structure of the rubber, the molecular weight and its distribution, and the aggregation state of the compounding agent all change.
Through mixing, the rubber and the compounding agent play a physical and chemical role, forming a new structure. Rubber compounds are dispersed systems with complex structural properties. Due to the high viscosity of the raw rubber, to make the compounding agent penetrate the raw rubber and uniformly mix and disperse it, the strong mechanical shearing action of the rubber mixer must be used.
Mixing with an internal mixer is safe in operation and low in labor intensity, and is currently the most common application. Mixing requires the compounding agent to be uniformly dispersed in the raw rubber to form a colloidal dispersion so that the vulcanizate has the best performance. At the same time, there are certain requirements for the plasticity of the compounded rubber, so that it can meet the requirements of the subsequent process.
There are one-stage and two-stage mixing methods. The former is to gradually add compounding agents to the rubber. The latter is to add softeners and powdery fillers for the first stage of rough mixing. After the rubber is cooled and placed for a certain period, sulfur and accelerators are added for the second stage of mixing. It is a rubber processing process in which rubber and various compounding agents are uniformly mixed in a rubber mixer. To be able to add the powder compounding agent to the rubber, the raw rubber must be masticated to improve its plasticity and fluidity. The mixing process is the most basic process of rubber processing. The quality of the mixed rubber after adding the compounding agent has a decisive influence on the process performance of the semi-finished product and the quality of the finished product.
The internal mixer is a kind of machine that is equipped with a pair of rotors with a specific shape and rotates relative to each other. It is a machine that intermittently masticates and kneads polymer materials in a closed state with adjustable temperature and pressure. It is mainly composed of an internal mixing chamber, and rotors. It is composed of a rotor sealing device, feeding, and pressing device, unloading device, transmission device, and machine base.
The internal mixer is a kind of high-strength intermittent mixing equipment developed based on the open mixer. The rubber mixing process shows a series of characteristics that are superior to open mills, such as large mixing capacity, short time, and high production efficiency. Rubber mixing can better overcome dust flying, reduce the loss of compounding agents, and improve product quality and the working environment. The rubber mixer is safe and convenient to operate, reduces labor intensity, and is beneficial to realize mechanical and automatic operations. Therefore, the appearance of the internal mixer is an important achievement of rubber machinery, and it is still typical important equipment in plasticizing and mixing, and it is still developing and improving.
The Basic Structure of the Mixer:
The internal mixer is generally composed of an internal mixing chamber, two relatively rotating rotors, an upper top bolt, a lower top bolt, a temperature measurement system, a heating, and cooling system, an exhaust system, a safety device, a discharge device, and a recording device. The surface of the rotor has helical protruding ribs, and the number of protruding ribs is two, four, six, etc. The cross-sectional geometry of the rotor is triangular, cylindrical, or elliptical, and there are two types of tangential and meshing. The temperature measurement system is composed of thermocouples, which are mainly used to measure the temperature change in the mixing chamber during the mixing process. The heating and cooling system is mainly to control the temperature of the rotor and the wall surface of the mixing chamber.
Working Principle:
When the mixer is working, the two rotors rotate relative to each other. The material from the feeding port is clamped and brought into the roll gap to be squeezed and sheared by the rotor. Along the gap between the front and rear chamber walls and the rotor and back to the top of the nip.
During the flow around the rotor, the material is subjected to shearing and friction everywhere, so the temperature of the compound rises sharply. The viscosity decreases, the wettability of the rubber on the surface of the compounding agent is increased, and the rubber and the compounding agent surface are fully contacted. The batch of compounding agents passes through the gap between the rotor and the rotor. The rotor and the upper and lower top bolts, and the inner wall of the mixer together with the rubber compound. It is sheared and broken, surrounded by stretched and deformed rubber, and stabilized in a broken state. At the same time, the rib on the rotor makes the rubber material move along the axial direction of the rotor, which plays a role in stirring and mixing so that the compounding agent is evenly mixed in the rubber material. The compounding agent is repeatedly sheared and broken in this way, the rubber compound repeatedly deforms and recovers, and the rotor ridges are continuously stirred so that the compounding agent is uniformly dispersed in the compound and reaches a certain degree of dispersion.
Because the shearing action of the rubber compound is much larger than that of the open mixer during the mixing of the internal mixer, and the temperature of rubber mixing is high. The efficiency of the rubber mixture in the internal mixer is much higher than that of the open mixer. The main parameters are the rotational speed and speed ratio of the rotor. The rotor edge ratio and the inner wall gap of the mixing chamber. Production capacity and filling factor, unit pressure of the top bolt on the compound.
Internal Mixer Mixing Process:
Mixing is the process of mixing raw rubber or masticating raw rubber and compounding agents into mixed rubber with a rubber mixer, and it is the most important production process in rubber processing. Essentially, it is a process in which the compounding agent is uniformly dispersed in the raw rubber. The granular compounding agent is in the dispersed phase, and the raw rubber is in the continuous phase. Mixing can use an open mill, internal mixer, and screw continuous mixer. In essence, the rubber mixing process is a process in which the compounding agent is uniformly dispersed in the raw rubber. The granular compounding agent is in the dispersed phase, and the raw rubber is in the continuous phase. During the mixing process, the molecular structure of the rubber, the molecular weight and its distribution, and the aggregation state of the compounding agent all change.
Through mixing, the rubber and the compounding agent play a physical and chemical role, forming a new structure. Rubber compounds are dispersed systems with complex structural properties. Due to the high viscosity of the raw rubber, to make the compounding agent penetrate the raw rubber and uniformly mix and disperse it, the strong mechanical shearing action of the rubber mixer must be used.
Mixing with an internal mixer is safe in operation and low in labor intensity, and is currently the most common application. Mixing requires the compounding agent to be uniformly dispersed in the raw rubber to form a colloidal dispersion so that the vulcanizate has the best performance. At the same time, there are certain requirements for the plasticity of the compounded rubber, so that it can meet the requirements of the subsequent process.
There are one-stage and two-stage mixing methods. The former is to gradually add compounding agents to the rubber. The latter is to add softeners and powdery fillers for the first stage of rough mixing. After the rubber is cooled and placed for a certain period, sulfur and accelerators are added for the second stage of mixing. It is a rubber processing process in which rubber and various compounding agents are uniformly mixed in a rubber mixer. To be able to add the powder compounding agent to the rubber, the raw rubber must be masticated to improve its plasticity and fluidity. The mixing process is the most basic process of rubber processing. The quality of the mixed rubber after adding the compounding agent has a decisive influence on the process performance of the semi-finished product and the quality of the finished product.
Reference: market-prospects
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