With the wide application of plastic products, the disposal of waste plastics has become a difficult problem and an urgent issue that needs to be solved in global environmental pollution. Therefore, it can be partially reused through the plastic granulation process.
Plastic products play an important role in various fields of industrial and agricultural production and life due to their excellent properties such as lightweight, high strength, corrosion resistance, and easy processing. With the rapid development of the plastic industry, the plastic granulator industry has also developed rapidly. The granulator can make recycled plastic products into plastic granules through various processes to achieve the effect of plastic reuse. The granulator industry involves many fields of the national economy. It is not only an indispensable basic production link for many industrial and agricultural products but also plays an important role in solving plastic pollution, improving the reuse rate of plastic products, and establishing and improving the plastic recycling system.
As a branch of environmental protection, the recycled plastics industry has more and more significance and responsibilities. In recent years, the disposal and recycling of waste plastics have been paid more and more attention by countries all over the world. The advantages of recycled plastic granulators also make them sustainable.
What is Granulation Processing?
Pelletizing equipment is a molding machine that can make materials into specific shapes. The process of high-temperature melting, plasticizing, and extrusion is used to change the physical properties of the plastic to achieve plasticizing and molding of the plastic. A plastic granulator is mainly used for processing waste plastic films, woven bags, agricultural convenience bags, basins, barrels, beverage bottles, furniture, daily necessities, etc. It is suitable for most common waste plastics and is the most widely used in the waste plastic recycling industry. The most widely used and most popular plastic recycling processing machinery.
Types of Granulators:
The granulator can be divided into single-screw granulators and twin-screw granulators according to the number of screws. When the single-screw granulator is working, the plastic is conveyed forward in a spiral shape in the barrel. When the twin-screw granulator is working, the plastic is transported forward in a straight line in the barrel. According to the working principle, when the twin-screw machine is stopped, the material in the machine can be emptied, and the single-screw machine stores a small amount of residual material. Most plastic granulation, single-screw, and twin-screw can be used indiscriminately.
How Does the Granulation Process Work?
Mixing granulation => Drying => Whole granulation => Final mixing (with vacuum suction).
- Drying: The drying speed of powder or granules is 10-20 times that of ordinary ovens. Using a high-pressure windmill, the powder or particles are floated in the drying room and the workshop. The hot air passes through the drying room from bottom to top and mixes with the particles vigorously. The drying efficiency is particularly good.
- Granulation: Spray the binder or the main ingredient on the flowing fine powder. After the granulation is completed, the instant solubility and fluidity of the granules become better. Spray the atomized binder or main ingredient on the floating powder to form the fine powder into uniform particles.
Most polymers must be compounded and then pelletized before being made into the final product, and the plastic is recycled into a reusable raw material. There are many different pelletizer designs, divided into cold pelletizing systems and die-face hot pelletizing systems, the difference between the two is the timing of the pelletizing process.
- Cold pelletizing system: The cold pelletizing system includes a die, a cooling zone roll mill, and a polymer sheet of a certain thickness that is calendared. The plastic flakes solidify and cool over a distance during transportation, and are then cut into round or square pellets with a pelletizer in a bin. Cold pelletizing systems, pelletizing from solidified polymer at the end of the process.
- Hot Pelletizing System: In a die face hot pelletizing system, pelletizing occurs as the molten polymer emerges from the die, while the pellets are cooled downstream.
The Composition of Plastic Granulator:
The main engine of the plastic granulator is the extruder system, which consists of an extrusion system, a transmission system, and a heating and cooling system.
The principle of extrusion system of plastic granulator:
The extrusion system of the plastic granulator includes a screw, a barrel, a hopper, a head, and a mold. The plastic is plasticized into a uniform melt through the extrusion system, and under the pressure established in this process, it is continuously fed by the screw. extruder head.
The principle of the transmission system of plastic granulator:
- Screw: It is the component of the principle of plastic granulator. It is directly related to the application range and production efficiency of the extruder. It is made of high-strength and corrosion-resistant alloy steel.
- Barrel: generally made of heat-resistant, high compressive strength, durable, corrosion-resistant alloy steel, or lined alloy steel.
- Hopper: The bottom of the hopper is equipped with a cut-off device to adjust and cut off the material flow, and the side of the hopper is equipped with a viewing hole and a calibration metering device.
- Die head: The die head is made of carbon steel and is equipped with a strip-forming die. The function of the machine head is to convert the rotating plastic melt into parallel linear motion, evenly and smoothly introduce it into the mold sleeve, and give the plastic the necessary molding pressure.
The function of the transmission system is to drive the screw and supply the torque and speed required by the screw during the extrusion process, which is usually composed of a motor, a reducer, and a bearing.
The principle of heating and cooling device of plastic granulator:
Heating and cooling are necessary conditions for the plastic extrusion process to proceed.
Applicable industries for Granulation:
- Pharmaceutical: Granulation and drying of traditional Chinese medicine, western medicine, and biotechnology products.
- Food: Granulation and drying of granules, fruit juice powder, meat powder, seasonings, lactic acid bacteria, and other products.
- Chemical industry: drying of synthetic raw materials; granulation and drying of powder.