Two-Stage-Extruder

Two Stage Extruder / PVC Compound Machine

The molecular weight of industrial PVC is generally in the range of 50000 ~ 110000kgs, with great polydispersity. The molecular weight increases with the decrease of polymerization temperature. There is no fixed melting point. It begins to soften at 80 ~ 85 ℃, changes to a viscoelastic state at 130 ℃, and changes to a viscous flow state at 160 ~ 180 ℃.

PVC granulation generally uses a two-stage machine. The upper stage adopts a twin-screw extruder, and the lower stage adopts a single screw extruder.

The temperature control system of the PVC compound machine can strictly control the material temperature according to the process requirements of customers, and the screw speed can be adjusted. The upper stage twin-screw extruder provides blending modification conditions for PVC raw materials, and the lower stage single screw extruder provides cooling time for PVC. After the air-cooling die face hot granulation auxiliary machine is used for granulation, the PVC pellets have good mechanical properties, high tensile strength and impact strength, and high-quality dielectric properties.

Generally, a high-speed mixer is required for mixing, and then it is cooled by the low-speed mixer. Then the raw materials are sent to the extruder, plasticized and mixed by the co rotating twin-screw extruder (L/D=28~36), and then cooled by a single screw at low temperature for pressure building extrusion. The length diameter ratio can be selected according to the needs of the formula.

PVC Compound Machine

Specially Extruder for PVC Compounding： Two Stage Extruder

Two Stage Extruder Processing Flow

Two-Stage Extruder Processing Flow

Upper Stage Extruder – Twin Screw Extruder

Lower Stage Extruder – Single Screw Extruder

PVC Compound Machine

Air-cooling die face hot granulation auxiliary machine

Air cooled die surface hot granulator: 4-stage motor, one set of hot cutting knives, one motor coupling, and 4 blades for hot cutting.

Speed regulation control: variable frequency speed regulation is adopted.

Pelletizing Hood: opposite blowing type, made of stainless steel. One piece. Push pull structure. With braking device. There is enough space for the heat shield to be separated from the machine head. Easy operation. The opposite blowing hot air hood is integrated with the bed.

Primary cyclone: φ 800mm, stainless steel. One piece. Use φ 160mm stainless steel pipe connection.

Air blown Silo: one set. One 1m3 silo is made of stainless steel. Use φ 130mm stainless steel pipe connection.

Precautions for Processing PVC Plastic Pellets

PVC can be said to be a common material in the plastic industry. It can be seen everywhere in people’s life. The skirting line beside the room wall, the switch face box on the wall, the pipe on the top of the toilet, and the plastic floor stepping on the floor are all made of PVC. PVC is the abbreviation of PVC. It is a polymer polymerized by vinyl chloride monomer with peroxide, azo compound and other initiators, or by a free radical polymerization reaction mechanism under the action of light and heat. Because of its low price and stable performance, it is widely used in various industries. The following points shall be paid attention to when processing PVC plastic pellets:

The processing temperature of PVC should not be too high. Generally, the processing environment of injection grade materials is about 160-170 ° C, and that of extruded materials is 160-190 ° C. beyond this temperature, PVC materials are prone to coke or material decomposition.

It is recommended to use PVC special screw for processing PVC plastic pellets. PVC has certain corrosivity due to the characteristics of the material. In order to prolong the service life of your screw, it is recommended to use a special grade.

The fluidity of PVC materials is worse than that of other materials. At this time, we generally recommend that users change the injection hole diameter to more than 3-5mm before processing, especially for larger products, which is more convenient for complete product molding.

Pay attention to the temperature change of the fuselage at any time. When touching the strip with clean hands, it should be heated immediately. Until the strip touches the hand, it is normal.

When the reducer bearing is burned or accompanied by noise, it shall be repaired in time and refuelled.

When the bearings at both ends of the main bearing chamber of the plastic granulator are hot or noisy, it is necessary to stop the machine for maintenance and add butter. During normal operation, grease the bearing chamber every 5-6 days.

Pay attention to finding out the operation law of the machine; For example, if the machine temperature is high or low and the speed is fast or slow, it can be handled in time according to the situation.

When the fuselage is unstable, pay attention to check whether the fitting clearance of the coupling is too tight, and loosen it in time.