Due to different production equipment, PVC cable material can be produced in the following four ways:
1. Two-roller refining and cutting: raw materials, ingredients, high speed mixer, mixing mill, cooling flume, drying, granulator, screening magnetic separation, measurement, packaging.
2. Single screw extruder granulation: raw materials, ingredients, high speed mixer, cooling mixer, single screw extruder, heating machine head, air cooling, screening magnetic separation, measurement, packaging.
3. Two-stage extruder (first-stage twin screw extruder, second-stage single screw extruder) granulation: raw materials, ingredients, high speed mixer, cooling mixer, double-stage extruder, heating head, air cooling, screening magnetic separation, measurement, packaging.
4. Twin screw extruder granulation: raw materials, ingredients, high speed mixer, cooling mixer, twin screw extruder, heating machine head, air cooling, screening magnetic separation, measurement, packaging.
Specific process:
1. Production process of double roll milling and cutting
(1) preparation: the colouring agent and filling agent shall be screened with 80 mesh screens respectively, and after being soaked with plasticizer, they shall be ground by three-roller grinding machine or colloid mill. Stabilizer, antioxidant, and a small amount of filler to join plasticizer, mix into a paste paste, and then USES three roll grinding machine or colloid mill grinding, make the slurry particle size is less than 0.050 mm, up to 90 ℃ and stirring, and set aside. The PVC resin was screened with a 60 mesh screen.
(2) the kneading: high speed mixer zhongtong into 0.2 MPa steam for heating, in PVC resin, and then slowly add grinding good mixture, after waiting for resin to absorb the plasticizer basic add filling agent, colorant, materials become loose powder discharge, the material temperature 110 ℃ or so at the moment. The whole process takes about 5-10 minutes.
(3) milling: steam pressure is 0.3-0.4mpa, compressed air pressure is 0.5mpa, mixing time is 3-5 minutes, upper end bolt is lifted for 2~3 times, the material is condensed into a mass, and the material is discharged when there is no powder.
(4) double roller mixing: 0.4 ~ 0.5 MPa steam pressure, temperature of 160 ~ 170 ℃ (insulation material appropriate high temperature) to completely after plasticizing uniform, to 3 mm thickness of the piece, the discharge should be uniform plasticizing, toughening and bright and clean, no raw material.
(5) cooling: counter-current immersion water cooling tank is adopted, and the blower removes the water stuck on the material sheet.
(6) granulation: the plate granulator is adopted. Cut cable material without strip, square and intergranular phenomenon.
(7) packaging: after screening, magnetic selection and measurement.
2. Ordinary single screw extruder granulation production process
(1) preparation: the stabilizer, filler and stain are screened with 80 mesh screens respectively, and the plasticizer is added and soaked separately, and then ground with a three-roller grinder or colloid. Weigh reserve. Plasticizer after mixing preheat to 90 ℃ for use; The resin was sieved through a 60 mesh screen.
(2) the kneading: in PVC resin, and adding plasticizer and stir for a moment, after waiting for resin to absorb the plasticizer is basic, add stabilizer, material by frictional heat temperature rise to about 90 ℃, then add filling agent, colorant, material temperature to 110 ℃, the material will be discharged to the cooling cooling mixer, below 45 ~ 50 ℃ during discharging.
(3) extrusion granulation, extrusion machine for SJ - 120/20 (for example) temperature is 80 ℃, 120 ℃, 160 ℃, 170 ℃, the nose 165 ℃ (plasticizers added quantity, temperature increase 5 ~ 10 ℃ or so); Extruder screw rotation speed 10~30 RPM; One layer each of 80 mesh and 120 mesh; The centrifugal fan with air pressure of 0.07MPa (544mmHg) and air volume of 2250m3/h and power of 7.5kw was adopted for air cooling.
(4) packaging: after screening, magnetic selection and measurement.
3. Double screw extruder granulation production process
(1) preparation and kneading process are the same as single screw extruder granulation process.
(2) the extrusion granulation: body temperature of 130 ~ 150 ℃; The nose temperature 140 ~ 186 ℃; Main engine speed is 5~15 RPM.
(3) packaging: after screening, magnetic selection and measurement.
4. Two-step extruder granulation production process
(1) preparation and kneading process are the same as single screw extruder granulation process.
(2) extrusion and granulation: the two-stage extruder is composed of two parts: the first stage is a high-speed co-directional twin screw mixer, and the second stage is a low-speed single screw extruder. The two parts are vertically and orthogonal, forming a two-stage compound unit. The advantages of the concentric twin screw and single screw are combined to complement each other. Forced conveying of twin screw, efficient plasticizing mixing and shear dispersion, no backpressure reflux of machine head, avoiding high shear overheat; Single screw extrusions at high pressure, but at low speed and low shear, also avoid overheating contradictions. Especially suitable for the processing of PVC and other heat sensitive materials. Double screw processing temperature 150 ~ 185 ℃, single screw temperature 130 ~ 165 ℃. The hot granule of air-cooled grinding surface is adopted, and the granule enters the hopper through cyclone separator and vibrating screen.
(3) packaging: after screening, magnetic selection and measurement.
The actual production of PVC cable material can be flexibly combined and matched according to the equipment and site conditions. The key is to ensure accurate formulation, sufficient and uniform mixing of materials and good plasticization. Because when the cable molding again by heating molding, so the temperature can not be too high.
At present, many cable materials are produced. In order to save trouble, the type and quantity of abrasive materials are reduced, and some quality problems are often caused when they are not mixed directly. |
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