Introduction to the structural characteristics and applications of chlorinated polyethylene CPE

I have been using CPE recently, so based on the literature introduction, I would like to summarize the relevant knowledge of CPE as follows:

1. Chlorinated polyethylene, also known as chlorinated polyethylene, abbreviated as CPE. Chlorinated polyethylene (CPE) is a material obtained by partially replacing hydrogen atoms on high-density polyethylene (HDPE) with chlorine atoms. CPE appears as a white powder, non-toxic and odorless.

2. Chlorinated polyethylene made from low-pressure polyethylene HDPE has better resistance to high temperature thermal aging than chlorinated polyethylene made from high-pressure polyethylene. Generally, polyethylene with a density of 0.93-0.96g/cm3, an average molecular weight of 50000 to 250000, and a melt index between 0.01 and 2.0g/10min is commonly used to produce chlorinated polyethylene. The degree of chlorination of chlorinated polyethylene has a significant impact on its properties. When the chlorine content is less than 15%, it is plastic; When the chlorine content is 16-24%, it is a thermoplastic elastomer; Rubber like elastomers with chlorine content between 25-48%; When the chlorine content is 49-58%, it is a semi elastic hard polymer similar to leather; When the chlorine content reaches 73%, it becomes a brittle resin. Introducing about 27% chlorine into high-pressure polyethylene completely eliminates crystallization, while introducing about 30% chlorine into low-pressure polyethylene with higher crystallinity also completely eliminates crystallization. As a rubber elastomer, the chlorine content is best within the range of 30-40%. At present, the chlorine content of commercial chlorinated polyethylene rubber is mostly in the range of 25-45%. When the chlorine content increases, the oil resistance, breathability, and flame retardancy improve; When the chlorine content decreases, the cold resistance, resilience, and compressive bending performance are better.

2. Characteristics of Chlorinated Polyethylene CPE

1) CPE is a saturated rubber with excellent heat and oxygen aging resistance, ozone aging resistance, acid and alkali resistance, and chemical properties.

2) CPE has excellent oil resistance, with excellent resistance to ASTM 1 and ASTM 2 oils, comparable to NBR; ASTM 3 oil has excellent performance, superior to CR and comparable to CSM.

3) CPE contains chlorine element, which has excellent flame retardant properties and combustion and anti dripping characteristics. It can be combined with antimony based flame retardants, chlorinated paraffin, and al (oh) 3 in appropriate proportions to obtain flame retardant materials with excellent flame retardancy and low cost.

4) CPE is non-toxic, free of heavy metals and PAHs, and fully meets environmental requirements.

5) CPE has high filling performance and can produce products that meet various performance requirements. The processing performance of CPE is good, and there are multiple grades to choose from with a Mooney viscosity (ml121 1+4) between 50-100.

3. Chlorinated polyethylene can be divided into two categories: resin type chlorinated polyethylene (CPE) and elastic type chlorinated polyethylene (cm). In addition to being used alone, it can also be blended with resins such as polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polystyrene (PS), ABS, and even polyurethane (PU). In the rubber industry, CPE can be used as a high-performance and high-quality specialty rubber, and can also be blended with other rubbers such as ethylene propylene rubber (EPR), butyl rubber (IIR), nitrile rubber (NBR), chlorosulfonated polyethylene (CSM), etc. Mainly used for: wires and cables (coal mine cables, wires specified in UL and VDE standards), hydraulic hoses, automotive hoses, tapes, rubber plates, PVC profile pipe modification, magnetic materials, ABS modification, etc.

4. CPE enhancers mainly consist of carbon black and white carbon black; The filling system mainly includes calcium carbonate, clay, and talc powder, etc; Plasticizers mainly include DOA and DOS; The commonly used stabilizers for CPE vulcanization include sodium stearate, magnesium oxide, barium stearate, and lead trisulfate, which mainly absorb hydrogen chloride produced during vulcanization.

5. CPE is a saturated rubber that cannot be effectively vulcanized by conventional sulfur vulcanization systems. The sulfurization system is divided into four major sulfurization systems: thiourea system, peroxide system, thiadiazole system, and triazole dimercaptoamine salt system.