The PVC flexible hose pipes are widely used in industries such as industrial engineering, agriculture, food, medicine, construction, wind power generation, etc., to absorb liquid, solid particles, and powdery materials such as drainage, oil, and low-concentration chemicals. Even items in our surroundings, such as water pipes, car wash water guns, and small pipes for watering flowers, are all PVC flexible hose pipes.
The PVC flexible hose pipe has the characteristics of colorless and smooth, light weight, beautiful appearance, good hand feeling, and softness, so how is it processed and produced? Polyvinyl chloride resin is the raw material, on the basis of which a relatively large amount of plasticizer is added, and then the ingredients are kneaded, extruded, granulated, molded, drawn, coiled, and packaged to form a finished product.
Weigh various raw materials accurately and put them into the kneader in a certain order. The feeding sequence is: PVC resin, plasticizer, stabilizer, lubricant. When the temperature reaches 100 to 110℃, the material can be discharged.
In this process, the temperature must be controlled. The highest point of the material temperature must be higher than the melting temperature of the material and lower than the extrusion temperature, that is, between 155 to 160°C. Granulation should achieve the purpose of full mixing and preliminary plasticization of the PVC flexible hose pipe.
The temperature of each zone of the granulator is as follows: 80 to 90°C in the first zone; 130 to 140°C in the second zone; 140 to 150°C in the third zone; 150 to 160°C in the machine head.
The temperature of extrusion tube molding is slightly higher. Generally speaking, the transparency of PVC flexible hose pipe is related to the molding temperature. Within a certain temperature range, the higher the temperature, the better the transparency, and vice versa.
At the same time, the traction speed and cooling speed will affect the transparency of the PVC flexible hose pipe. The traction speed is slightly higher, the cooling speed is fast, and the transparency of the pipe is better.
The traction speed is generally 10% to 15% faster than the extrusion speed; the cooling of the transparent hose: first it is sprayed with cold water at the die mouth of the machine head, and then enters the water tank for cooling.
The temperature of each zone of the extrusion tube: 90±5°C in the first zone; 140±5°C in the second zone; 160±5°C in the third zone; 170±5°C in the fourth zone.
(1) When directly extruding with powder, the temperature of the extruder is about 5℃ lower than that of pellets.
(2) Except for PVC flexible hose pipe blanks with smaller diameters (below φ60mm) that do not need compressed air to be blown in for cooling and shaping, compressed air must be blown into the pipes when the pipes with larger diameter are cooled to ensure the accuracy and stability of the pipe diameter. Note that the compressed air pressure should be stable.
(3) Pay attention to the stability of the traction speed, and avoid changes in the diameter of the PVC flexible hose pipe pipe or the thickness of the PVC flexible hose pipe due to unstable traction.
(4) When the machine is shut down for a long time, the PVC flexible hose pipe manufacturer must disassemble the machine and clean it to avoid the problem of decomposition of the PVC flexible hose pipe.
