Chlorinated Polyethylene (CPE)
1.Material Overview
Chlorinated polyethylene (CPE) is a novel polymer material obtained by chlorinating high-density polyethylene under pressure. Due to differences in the content, arrangement, and degree of crystallinity of its three components, CPE combines the properties of thermoplastic resins (rigid resins, translucent resins) and elastomer rubbers. Because of its good stability, excellent heat resistance, aging resistance, and flame retardancy, CPE is widely used in thermoplastic blending modification.
Chlorinated polyethylene (hereinafter referred to as CPE) is divided into two main categories: plastic modified type and rubber type. It is further divided into multiple grades according to different technical indicators and is widely used in general plastics such as polyvinyl chloride modification, flame retardant ABS, magnetic materials, soft products, modified PE, wire and cable automotive hoses and industrial hoses, various professional rubber products, and in combination with other rubbers.
2.Process Introduction
This production unit uses the acid phase method to produce CPE. The main processes include: chlorination, deacidification, centrifugal dehydration, drying, storage and packaging, tail gas absorption, wastewater treatment, and liquid chlorine storage.
Polyethylene (PE) is prepared into a hydrochloric acid suspension in a mixing tank using approximately 20% hydrochloric acid. This suspension then enters a chlorination reactor. Under precise control of the cooling/heating system, chlorine is introduced to initiate the chlorination reaction. After the chlorination reaction is complete, a flat rotary vacuum filter is used for continuous deacidification. The washed material is discharged, and a portion of the removed 22% hydrochloric acid is recycled, while the remainder can be sold commercially. The deacidified wet material is then continuously centrifuged in a screw screen centrifuge , followed by drying and other processing steps to obtain the finished product.
3.Technical Advantages
The production process utilizes the most advanced hydrochloric acid suspension process technology. This advanced and flexible technology is suitable for producing a series of highly differentiated products to meet the needs of users with diverse applications. Using high-concentration hydrochloric acid as the medium ensures uniform chlorination, resulting in products with excellent flexibility and high whiteness, making them particularly suitable for high-end plastics and rubber products. All byproduct hydrochloric acid is recycled, making it a clean and environmentally friendly technology.
Using the world's most advanced control system, comprehensive control of multiple parameters is achieved through single-channel PID regulation or multi-loop cascade regulation, ensuring that the entire process control can precisely follow the pre-set program. For example, the fluctuation range of the key control indicator, reaction temperature, in CPE production can be controlled within ±0.1℃, ensuring that all technical indicators of the product fully meet the set requirements.
The main equipment used in the production of chlorinated polyethylene, such as chlorination reactors, plate filters, centrifuges, dryers, and grinding mills, has all been imported . A unique 60m³ enamel-lined reactor, along with a stirring and frequency conversion system, ensures stable and orderly reaction processes. Plate filters and centrifuges made of special materials efficiently achieve continuous operation of deacidification, washing, and centrifugation processes. An antistatic vertical airflow drying system and grinding system ensure stable and uniform product quality.
4.Technical Benefit
1. Because the acid phase method has a shorter process route and the chlorination product has a higher porosity, the energy consumption in the production process is much lower.
The acid phase method is significantly less expensive than the aqueous phase method in terms of the number of operators, equipment maintenance costs, and pollutant treatment.
3. Hydrochloric acid produced as a byproduct of the acid phase process can be recycled and reused (for sale, analysis to produce HCl , or production of other chlorides). Hydrochloric acid produced as a byproduct of the aqueous phase process has virtually no utilization value due to its extremely low concentration. Furthermore , because it contains organic matter ( COD content of 150-500 ppm ) , neutralization and treatment are difficult and costly .
4. The particles of the acid phase method are porous with a large specific surface area, while the particles of the aqueous phase method are relatively smooth spherical with a smaller specific surface area.