Comparison of PE Pipe, PVC Pipe, and PP Pipe Extrusion Line

In the plastic pipe industry, polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) are the three main materials, each widely used in water supply, drainage, gas, HVAC, chemical, and agricultural irrigation fields due to their unique physical and chemical properties. Although they are all manufactured using the “extrusion molding” process, due to significant differences in raw material characteristics, their corresponding extrusion production lines differ significantly in equipment configuration, process parameters, control systems, and even environmental requirements.

Raw Material Characteristics Determine the Process Route

PE (Polyethylene): A thermoplastic non-polar material with low melt strength and high viscosity, but good thermal stability and a wide processing temperature range (180–230℃). It is non-toxic and odorless, suitable for hot and cold water and food-grade pipes.
PVC (Polyvinyl Chloride): Highly heat-sensitive, with a processing temperature close to its decomposition temperature (160–195℃), requiring the addition of a large amount of stabilizers and lubricants; usually processed in powder form, requiring high demands on mixing and degassing.
PP (Polypropylene): A crystalline material with a high melting point (approximately 160–170℃), a processing temperature of 200–240℃, and excellent high-temperature resistance, but it is easily oxidized and requires the addition of antioxidants; mostly used in hot and cold water, chemical, and underfloor heating systems.
Therefore, the production lines for these three types of pipes differ significantly in key aspects such as “whether mixing is required,” “whether degassing is needed,” and “temperature control accuracy.”

Significant Differences in Extrusion Machine Configuration

1. Screw Type
PE pipes: Generally use single-screw extruders, with an L/D ratio of 25:1–30:1, barrier or separation screw design, emphasizing uniform plasticization and low shear;
PVC pipes: Must use conical twin-screw extruders (a few use parallel twin-screw extruders), with low shear, strong mixing, and built-in degassing function to prevent powder degradation;
PP pipes: Mostly use single-screw extruders, but require a higher length-to-diameter ratio (L/D ≥ 30:1) and precise temperature control. Some high-end production lines use barrier screws to improve melt homogeneity.

2. Driving and Heating
PE and PP production lines have widely adopted servo motors + electromagnetic induction heating in recent years, offering energy efficiency;
PVC production lines, due to frequent starts and stops and large torque fluctuations, prioritize high starting torque and overload protection, and often use ceramic infrared heating rings to prevent localized overheating.

Forming and Sizing Systems: Different Approaches

Mold Design
PE pipes: Commonly use straight-through or side-feed molds with smooth flow channels;
PVC pipes: Molds require corrosion resistance and high surface finish, often equipped with a compression section to compact the powder melt;
PP pipes: Sensitive to die lip temperature, requiring zoned heating to prevent cold marks.
Cooling and Sizing
PE pipes: Rely on vacuum sizing tanks + spray water troughs, with moderate cooling speed to avoid internal stress;
PVC pipes: High vacuum sizing requirements due to low melt strength, requiring rapid suction and sizing, with stricter water temperature control (usually 15–20℃);
PP pipes: Cooling needs to be more uniform and gradual, especially for PP-R hot water pipes, often using atomized cooling + water film lubrication technology to reduce warping and shrinkage.

Auxiliary Systems and Environmental Requirements

Raw Material Processing:
PE and PP mostly use granular materials, requiring only drying (depending on humidity) and automatic feeding;
PVC must be equipped with a high-speed hot mixing + cold mixing system to complete powder premixing, which is a unique pre-process for its production line.
Exhaust and Environmental Protection:
PVC extrusion releases HCl gas, so the production line needs to integrate vacuum exhaust + waste gas treatment devices (such as alkaline solution spraying or activated carbon adsorption);
PE/PP basically produce no harmful gases, resulting in less environmental pressure, but high-end production lines are also starting to install VOCs collection systems to meet green factory standards.
Cutting Method:
Large-diameter PE gas pipes often use planetary flying knife cutting;
PVC rigid pipes commonly use rotary saw blade cutting;
PP-R pipes, due to their good toughness, require sharp tools and stable traction to avoid drawing.

Intelligentization and Future Trends

Three types of production lines are simultaneously evolving towards intelligent manufacturing, but with different focuses:

PE pipe production lines: Focusing on online wall thickness control and carbon footprint tracking, serving high-standard projects such as gas and water supply;
PVC pipe production lines: Emphasizing digital formula management and lead-free process adaptation, responding to environmental regulations;
PP pipe production lines: Focusing on the development of multi-layer co-extrusion (such as antibacterial layers and oxygen barrier layers) and high-temperature stability control, expanding applications in medical and clean room fields.
In addition, all production lines are advancing industrial 4.0 technologies such as digital twins, AI quality prediction, and remote operation and maintenance. However, due to the complexity of the process, PVC requires higher system robustness; while PE/PP focuses more on energy efficiency optimization and flexible switching.

Although PE, PVC, and PP pipes all belong to plastic pipes, their inherent material differences determine the “similar form but different nature” of their extrusion production lines in terms of structure, process, and control logic. Companies should not simply apply generic solutions when planning production lines—

If the focus is on municipal water supply or gas, high-stability PE pipe production lines should be prioritized;
If the focus is on building drainage or electrical conduits, mature and reliable PVC powder extrusion lines remain the mainstream;
If entering the high-end home improvement or industrial high-temperature resistant pipe market, investment in high-precision PP-R dedicated production lines is necessary.
Only by “matching the machine to the material” can companies achieve efficient, high-quality, and sustainable production goals and gain a competitive advantage in their respective market segments.