Durastream CPVC Frequently Asked Questions
With more than 65 years of production and fabrication experience, SEKISUI CHEMICAL is a world leader in PVC (polyvinyl chloride), CPVC (chlorinated polyvinyl chloride) resin, and CPVC compound for building, automotive, aircraft, and medication markets.
Durastream CPVC is high-performance compound commonly used in extruded pipes and profiles, injection-molded fittings, and calendared sheet, due to the compound’s high-heat deflection, flame retardance, smoke suppression, and superior corrosion resistance. Durastream CPVC forms strong, durable components that consumers and manufacturers can rely on. As one of the leading producers of this versatile thermoplastic, we are happy to share a few frequently asked questions and answers.
Frequently Asked Questions
PVC (polyvinyl chloride) is a trusted thermoplastic often used for piping and fitting in residential and commercial building applications.
CPVC (chlorinated polyvinyl chloride) is a PVC homopolymer that is produced through a chlorination reaction involving either heat or light. Chlorine (Cl2) is added to the PVC and reacted through a basic free radical mechanism. See the figure below.
The resulting CPVC resin is more resistant to heat, pressure, and fire than the PVC it came from. The degree chlorination for CPVC is linked to this improved performance. For example, if the degree of chlorination is increased by 1%, HDT (heat deflection temperature) would likely increase 4-5%.
CPVC is produced using PVC, water, and chlorine.
Photochlorination (UV or light energy) is the most popular chlorination method, but SEKISUI’s proprietary technology uses thermal chlorination (heat energy). See figure below for the 4 step process.
CPVC is produced using PVC, water, and chlorine.
Photochlorination (UV or light energy) is the most popular chlorination method, but SEKISUI’s proprietary technology uses thermal chlorination (heat energy).
Using the heat chlorination method during molding slows the rate of CPVC dehydrochlorination, requires less stabilizer, and results in CPVC resin that less likely to burn. 
CPVC has several key performance characteristics that differentiate it from PVC.
- Heat Resistance
Heat Resistance is 10-40℃ higher than PVC. CPVC can be used for high temperature
applications like hot water pipes.
- Mechanical Properties, Strength
Superior mechanical properties specifically at high temperatures outside the PVC range
- Chemical Resistance
Superior chemical resistance in acidic or alkaline condition, making CPVC the better choice for industrial and chemical applications
- Flame Retardance
Superior flame resistance. The optimal choice for fire sprinkler systems.
- Relatively low cost
CPVC is reasonably priced when compared to comparable engineering thermoplastic material