Durastream CPVC FAQ

With more than 65 years of production and fabrication experience, SEKISUI is a world leader in polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC) resin and CPVC compounds for building, automotive, aircraft and medication markets.

Durastream CPVC is a high-performance compound that manufacturers commonly use in extruded pipes and profiles, injection-molded fittings and calendared sheet. You often see CPVC in these products because of its high heat deflection, flame retardance, smoke suppression and superior corrosion resistance.

Additionally, Durastream CPVC forms strong, durable components that consumers and manufacturers can rely on. As a leading producer of this versatile thermoplastic, we’re happy to offer answers to common questions in our Durastream CPVC FAQ.

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FAQ

Polyvinyl chloride (PVC) is a trusted thermoplastic that manufacturers often use for piping and fitting in residential and commercial building applications.

Meanwhile, chlorinated polyvinyl chloride (CPVC) is a PVC homopolymer that we produce through a chlorination reaction involving either heat or light. We then add chlorine (Cl2) to the PVC and react it through a basic free radical mechanism. See the figure below.

durastream cpvc compound graphic

The resulting CPVC resin is more resistant to heat, pressure and fire than the PVC it came from. Interestingly, the degree of chlorination for CPVC links to this improved performance. For example, if the degree of chlorination increases by 1%, then heat deflection temperature (HDT) would likely increase by 4-5%.

We produce CPVC 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 the figure below for the four-step process.

cpvc production graphic

We produce CPVC 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).

cpvc heat chlorination graphic

Using the heat chlorination method during molding has marked benefits:

  • Slows the rate of CPVC dehydrochlorination
  • Requires less stabilizer
  • Results in CPVC resin that’s less likely to burncpvc test method graphic

Several key performance characteristics differentiate CPVC from PVC.

  • Heat resistance

For example, its heat resistance is 10-40℃ higher than that of PVC. Manufacturers can use CPVC for high-temperature applications, like hot water pipes.

  • Mechanical properties, strength

CPVC has superior mechanical properties, specifically at high temperatures outside the PVC range.

  • Chemical resistance

It has superior chemical resistance in acidic or alkaline conditions, which makes CPVC the better choice for industrial and chemical applications.

  • Flame retardance

CPVC has superior flame resistance. This makes it the ideal choice for fire sprinkler systems.

  • Relatively low cost

Additionally, CPVC has a reasonable price when compared to similar engineering thermoplastic materials.