CPVC / Corzan

Chlorinated polyvinyl chloride (CPVC) is a thermoplastic produced by chlorination of polyvinyl chloride (PVC) resin. Uses include hot and cold water pipe, and industrial liquid handling.

Although it is derived from PVC and thus shares some of that material’s characteristics, CPVC is a distinct polymer. It is a high-temperature-grade chlorinated polyvinyl chloride that is resistant to corrosion, heat, and chemicals.  CPVC can be easily machined with standard woodworking tools and can be fiberglass-backed, hot-air welded with rod, cemented (solvent bonded), riveted, and threaded. This material is useful for a wide range of applications, from chemical processing to metal finishing.

Chlorinated Polyvinyl Chloride (CPVC) is PVC (polyvinyl chloride) that has been chlorinated via a free radical chlorination reaction. This reaction is typically initiated by application of thermal or UV energy utilizing various approaches. In the process, chlorine gas is decomposed into free radical chlorine which is then reacted with PVC in a post-production step, essentially replacing a portion of the hydrogen in the PVC with chlorine.

Depending on the method, a varying amount of chlorine is introduced into the polymer allowing for a measured way to fine tune the final properties. The chlorine content may vary from manufacturer to manufacturer; the base can be as low as PVC 56.7% to as high as 74% by mass, although most commercial resins have chlorine content from 63% to 69%.[citation needed] As the chlorine content in CPVC is increased, its glass transition temperature (Tg) increases significantly. Under normal operating conditions, CPVC becomes unstable at 70% mass of chlorine.

Various additives are also introduced into the resin in order to make the material processable. These additives may consist of stabilizers, impact modifiers, pigments and lubricants.

Comparison to polyvinyl chloride (PVC)

Heat resistance

CPVC can withstand corrosive water at temperatures greater than PVC, typically 40°C to 50°C (104°F to 122°F) or higher, contributing to its popularity as a material for water piping systems in residential as well as commercial construction.

Mechanical properties

The principal mechanical difference between CPVC and PVC is that CPVC is significantly more ductile, allowing greater flexure and crush resistance. Additionally, the mechanical strength of CPVC makes it a viable candidate to replace many types of metal pipe in conditions where metal's susceptibility to corrosion limits its use.

Fire properties

CPVC is similar to PVC in resistance to fire. It is typically very difficult to ignite and tends to self-extinguish when not in a directly applied flame.

Due to its chlorine content, the incineration of CPVC, either in a fire or in an industrial disposal process, can result in the creation of chlorinated dioxins.

Physical properties

CPVC shares most of the features and properties of PVC. It is also readily workable, including machining, welding, and forming. Because of its excellent corrosion resistance at elevated temperatures, CPVC is ideally suited for self-supporting constructions where temperatures up to 200 °F (90 °C) are present. Due to its specific composition, dealing with CPVC requires a specialized solvent cement, with high strength solvent cement variants being first introduced in 1997 by Weld-On, then followed closely by other products such as Henkel's Tangit line. The ability to bend, shape, and weld CPVC enables its use in a wide variety of processes and applications. It exhibits fire-retardant properties.

Key Properties

Good impact properties

Resistant to corrosion, heat, and chemicals

Inherent flame resistivity

Easily machined

Retains physical properties at high temperatures

Standard Shapes and Forms

Sheet: .030” – 2” thick

Rod: .250” – 7” diameter

Tubular Bar:  1.625” – 6.625” OD / .562” – 4” ID

Other Forms:  Welding rod, Profiles: hex rod, angle and Pipe & Fittings

A Corrosion Guide is available on the Pipe & Fittings page and the Technical Specifications page.

The range of sizes and shapes are grade specific, please contact us for more information.

Colors

Light gray – standard

                TYPICAL PROPERTIES OF CORZAN/CPVC

ASTM or ULtest       Property                          Units                        Value

PHYSICAL

D792                      Specific Gravity              g/cm3                       1.47

D570                      Water Absorption           %                             0.03

D785                      Rockwell Hardness         R Scale                     116

D1784                    Cell Class                     -                              24446-B

MECHANICAL

D256                      Izod Impact (Notched)   ft-lb/in o.n.               9

D638                      Tensile Strength            psi                          7300

D790                      Flexural Strength           psi                          14,300

D790                      Flexural Modulus           psi                          361,000

D695                      Compressive Strength    psi                          10,100

D695                      Compressive Modulus     psi                         196,000

THERMAL

D696             Coefficient of Thermal Expansion  in/in/°F                3.86 × 10^-5

C177                      Thermal Conductivity         BTU/in/hr/ft3/°F    0.95

D648                      Heat Distortion Temperature @ 264 psi °C /°F  92/198

FLAMMABILITY RATINGS

UL94                      Flammability                      V-0, 5VB, 5VA            0.062'

E84                         Flame Spread                    -                              15

D2863                    Limiting Oxygen Index        %                             60

ELECTRICAL

D147                      Dielectric Strength                Volt/MIL                  1250

D150                      Dielectric Constant               60 HZ                      3.70

D150                      Power Factor                       1000 HZ                   0.007%

D257                      Volume Resistivity               Ohm/cm                  3.4 × 10^15

CPVC / Corzan Pictures