What Is Chlorinated Polyethylene? Properties and Applications Explained

What Is Chlorinated Polyethylene?

Chlorinated Polyethylene , also known as CPE or CM, is a saturated polymer material produced through the chlorination of High-Density Polyethylene (HDPE). It is a functional polymer that combines characteristics of both rubber and plastic. CPE typically appears as a white powder or granular material and is non-toxic and odorless.

Main Properties of Chlorinated Polyethylene

(1) Excellent Weather Resistance and Aging Resistance

As a saturated polymer, CPE has a stable molecular structure that provides outstanding resistance to thermal oxidation, ozone aging, and environmental degradation. It can maintain long-term performance even under harsh weather conditions and demanding service environments.

(2) Good Chemical Resistance

CPE exhibits excellent resistance to a wide range of chemicals, including acids, alkalis, and salts. Its resistance to oxidizing acids, such as concentrated sulfuric acid and nitric acid, is superior to that of many general-purpose rubbers. It also offers better resistance to oils and solvents than conventional polyethylene.

(3) Excellent Low-Temperature Toughness

CPE maintains good flexibility and toughness at low temperatures. It can remain flexible at temperatures as low as -30°C, and its brittle point is below -70°C. This makes it an ideal modification material for products used in cold environments.

(4) Good Flame Retardancy

The chlorine content in CPE provides inherent flame-retardant properties. It offers self-extinguishing characteristics and helps reduce dripping during combustion. As a result, CPE is widely used in flame-retardant formulations and materials.

(5) Good Compatibility with Other Materials

CPE is highly compatible with a variety of plastics and rubbers, including PVC, PE, PP, PS, and ABS. It also demonstrates excellent filler acceptance, making it beneficial for formulation flexibility and cost optimization.

Types of Chlorinated Polyethylene

(1) Resin-Type Chlorinated Polyethylene (CPE)

Resin-type CPE generally contains 25%–45% chlorine and appears as a white powder. It is a thermoplastic resin that retains some crystalline regions. This type is primarily used as an impact modifier for PVC, significantly improving the toughness and impact resistance of rigid PVC products.

Due to its wide availability and cost-effectiveness, resin-type CPE has become one of the most widely used impact modifiers in the PVC industry, particularly in China.

(2) Elastomer-Type Chlorinated Polyethylene (CM)

CM, also known as Chlorinated Polyethylene Rubber, typically contains 30%–40% chlorine and appears as a white granular elastomer. The chlorine atoms are randomly distributed along the polymer chain, forming a saturated elastomer with a fully amorphous structure and no residual crystallinity.

CM is a high-performance specialty synthetic rubber commonly used in wire and cable jacketing, automotive hoses, flame-retardant conveyor belts, and other rubber products requiring excellent weatherability and heat resistance.

(3) High-Chlorinated Polyethylene (HCPE)

HCPE contains more than 65% chlorine and is typically supplied as lightweight white granules. It is soluble in organic solvents and is mainly used in anticorrosion coatings, fire-resistant coatings, premium printing inks, and specialty adhesives.

Compared with traditional chlorinated rubber, HCPE offers a more environmentally friendly production process and is widely regarded as an ideal replacement material in many coating and adhesive applications.

Applications of Chlorinated Polyethylene

(1) Construction Materials

CPE, especially elastomeric CM grades, is widely used in the construction industry because of its durability, flexibility, and resistance to environmental aging.

Waterproofing Membranes: Used in roofing systems, underground waterproofing projects, and building foundations due to its excellent weather resistance and long service life.
Door and Window Seals: Provides excellent elasticity, UV resistance, and long-term durability.
Cable Sheathing: Commonly used for outdoor and flame-retardant cables because of its superior weather, oil, and chemical resistance.

(2) PVC Modification (Primary Application)

PVC impact modification is the largest and most important application of CPE

Significantly improves the impact strength of rigid PVC products.
Widely used in PVC pipes, fittings, profiles, sheets, and siding.
Enhances toughness and low-temperature performance without negatively affecting processing characteristics.
Improves weather resistance and extends the service life of finished PVC products.

(3) Rubber Products (CM Grade)

Elastomeric CPE, commonly known as CM rubber, is used in various industrial rubber applications that require durability and resistance to heat, weather, and chemicals.

Industrial Hoses and Seals: Provides excellent resistance to oils, chemicals, and aging.
Flame-Retardant Conveyor Belts: Offers enhanced safety in mining and industrial environments.
Automotive Rubber Components: Used for hoses, seals, and protective covers exposed to outdoor conditions.

(4) Coatings and Adhesives (HCPE)

Highly Chlorinated Polyethylene (HCPE) is widely used in protective coatings, specialty adhesives, and industrial inks.

Anti-Corrosion Coatings: Applied to steel structures, pipelines, bridges, and marine facilities.
Industrial Protective Coatings: Used on chemical storage tanks, containers, and industrial equipment.
Adhesives and Printing Inks: Provides strong chemical resistance, excellent adhesion, and long-term durability.

(5) Other Applications

In addition to the major applications above, CPE is also used in several specialized fields.

Flame-retardant conveyor belt compounds.
Specialty protective and fire-resistant coatings.
Polymer blends requiring improved flexibility and impact resistance.
Wire and cable compounds with enhanced weatherability and flame-retardant performance.