The production of PVC transparent film and the

PVC, or polyvinyl chloride, is a common plastic material in our lives, and the plastic wrap we use is a kind of transparent PVC film. PVC film has many characteristics, including strong transparency, light weight, hardness can be strong or weak, and low cost. These characteristics can be mass-produced. This polymer has become the second largest production material in plastics. See its 'shadow'.

The main method of producing PVC is the suspension method, which is also a method of producing PVC films. The polymerization process is carried out in a stirred reactor, using batch operation. The reaction process includes non-ionized water metering control system, polymerization kettle temperature control system, buffer metering control system.

????The polymerization process is operated by hot water feeding method, that is, non-ionized water is heated to about 48 degrees Celsius and then added to the polymerization kettle to increase the temperature of the raw materials in the kettle and shorten the heating time. Non-ionized water should use two turbine flowmeters connected in series on the same horizontal feeding pipe as far as possible, with a distance of 2.5m between them. The temperature of the deionized water after the mixing of cold and hot deionized water is controlled by a separate range to control the cold and hot deionized water control valves. After mixing, the temperature of the feed ion-free water flow is temperature compensated. Among them, there are instruments for measuring the volume of the feed and the feed meter used for metering, and the opening of the feed control valve is controlled by the controller. The feed pressure has a minimum soft limit. When the feed pressure is lower than the set value, the pressure controller replaces the flow controller to control the feed volume and prevent the turbine flowmeter from being vaporized due to the low outlet pressure. Cause the error of the flowmeter reading. If the meter fails, the system also sets up a metering tank, which is calibrated with a weighing meter. In order to make the metering correct, the control system is set with two feed flow rate settings: full flow rate and micro flow rate, which can reach 136m3 / h at full flow rate and only 23m3 / h at micro flow rate. The system uses micro flow rate to control the feed until the set metering value is reached and the feed control valve is closed. The entire control system is implemented with a computer control device. Therefore, a feed cut-off solenoid valve is also provided after the feed control valve to automatically open and close the metering control system.