Regeneration technology of hard PVC hollow floor
DATE：2022/3/23 8:44:53 / READ： / SOURCE：This station
Regeneration technology of hard PVC hollow floor
1. Performance comparison and ratio of waste materials and new materials(1) The relative molecular weight distribution of different waste and defective pellets is high, and the waste and defective pellets filled with R-PVC hollow floor are extremely uneven. There may be primary waste pellets, secondary waste pellets, and even tertiary waste pellets; There are normal leftover materials and yellowing decomposition materials. The relative molecular weight distribution of each batch of samples was measured by liquid chromatograph, and the measured data were made into differential distribution curve. It can be seen from the differential distribution curve that the relative molecular weight distribution is also different with different processing experience, or different processing and recovery times. Each time of processing, the relative molecular weight distribution will change, that is, the degree of polymerization and branching of macromolecules will change. In this way, the change of molecular structure will inevitably affect the fluidity and thermal stability of materials.
(2) It is necessary to add an appropriate amount of processing modifier into the waste defective pellets; At the same time, considering the consumption of heat stabilizer and the volatilization of volatile components (such as plasticizer) in the processing process, it is also very necessary to supplement heat stabilizer and volatile components appropriately. Therefore, the relevant components were added in the recovery of waste and defective granular material of high filled R-PVC hollow floor, and the test was carried out. From the rheological data, it can be seen that the processing flow performance and stability of waste and defective granular material (2) are worse than that of newly mixed powder (1); However, when 1.5 parts of Epoxy Soybean (4) is added to the waste and defective granular material, its processing performance and thermal stability are better than those of pure processing and recycling waste and defective granular material, which is almost close to the level of new mixture; After adding 2 parts of ACR processing aid k-125 (6), its processing performance should have been improved, but compared with (4), the balance torque and melting time increased; The reason for this abnormal situation may be that the batch of waste materials used has changed, which also reflects the non-uniformity of waste and defective granular materials and the instability of processing performance. Casting film production line www.handern.com com
2. Main equipment
15 production (2) V30 hot / cold mixing unit, etc.
3. Preparation process
(1) Process flow chart
Casting film production line of impact modifier and stabilizer www.handern.com com
Start stop feeding 7
Waste and defective materials are broken by a crusher, sand and soil are removed, iron is removed by an electromagnetic suction cup - high-speed mom concrete collar
Corner leftover material J
Low speed cold mixing → twin screw extrusion - traction - cutting - Inspection - Packaging - product figure 2-34 high filling - PVC hollow floor waste recovery process flow casting film production line www.handern.com com
(2) Only by realizing the uniform dispersion of each component in the formula, can it lay a foundation for smooth extrusion and improving product quality. In addition to accurately weighing according to the process formula, the principle of activating light calcium carbonate first and then mixing with resin and other additives must be followed. That is, first put the light calcium carbonate and stearic acid into the mixing chamber of the high-speed mixer. When the mixing material temperature rises to 75 ℃, put in the new PVC resin material and waste material, then add the stabilizer at 95 ℃, add the anti impact agent, add the stabilizer at 100 ℃, the material temperature reaches 115 ℃, the discharge door automatically opens, the hot mixed material is put into the cold mixer, the paddle is stirred slowly, and the jacket is cooled with water to make the material loose. When the material temperature drops to 40 ℃, it can be transported to the hopper of the extruder for use. It must be noted that the room temperature is high in summer. If the mixing end temperature exceeds 120 ℃, it is likely to overheat and decompose the materials in the mixer. Casting film production line www.handern.com com
(3) When the extruder and each section of the die are heated according to the process requirements Carefully check the temperature control points of the drawing and shaping equipment and the extrusion temperature control system. After the temperature of each section reaches the set value, it is necessary to keep constant temperature for 45 ~ 60min to ensure uniform temperature. The middle of the barrel of the twin-screw extruder is equipped with an exhaust hole and a vacuum pumping device, so the powder must be plasticized before reaching the exhaust hole, and the temperature of the barrel before the exhaust hole must be higher. Otherwise, the powder will be sucked out by the exhaust hole to block or damage the vacuum device, which is also the difference from the temperature rise of the three stages of single screw extrusion (feeding → compression → extrusion).
Taking the high filled r-pvc55mm hollow floor as an example, the main process control parameters are listed in table 2-60. Casting film production line www.handern.com com
Author：admin