CPVC vs PVC Processing Differences

Can We Use a PVC Machine for CPVC Production?

The CPVC process using extrusion and injection is very similar to the PVC process.

Additionally, you can typically use PVC equipment and tools in the CPVC manufacturing process. However, proper temperature settings, screws and molding tools are necessary.

What Is the Main Difference Between CPVC and PVC Processing?

The main difference between PVC and CPVC processing lies in thermal stability and viscosity.

If you don’t apply moderate temperatures and heat to CPVC, it won’t melt, and its physical properties won’t perform well. Hydrochloric acid decomposes when exposed to high temperatures. For reference, we’ve illustrated the crystalline melting points for PVC and CPVC below.

Can We Use a PVC Machine for CPVC Production?

Key Points

PVC and CPVC materials have different thermal stabilities:

• CPVC materials must reduce the residence time of the molding tools as much as possible.
• Resin temperature settings are important to ensure the material’s melting and gelation.

Viscosity (Fluidity)

Generally, CPVC’s viscosity is higher than that of PVC. You can simply read PVC’s viscosity as K-Value = Polymerization. For CPVC, you calculate viscosity (K-Value) by PVC polymerization degrees and chlorination degrees.

Key Points

• Motor load, back pressure
  If back pressure is high and increasing production speed is difficult, the material will remain inside the die longer and burn.
• Screw/mold shape
  The structure of the screw and die tools is an important factor. You must match the tools with CPVC production.
• Attention to shear heating
  The screw undergoes shear heating. As a result, moderate heat is necessary to keep the plastic at the correct temperature.