PVC vs WPC Profile: Differences and Production Process

PVC profiles and WPC profiles are two mainstream plastic profiles used in the construction and decoration industry today. They differ significantly in raw materials, performance, and applications, thus there are also key differences in profile production line.

Differences in Raw Materials:

• PVC (Polyvinyl Chloride) Profiles

Main components: Polyvinyl chloride resin, stabilizers, lubricants, processing aids, fillers (such as calcium carbonate), etc.

Common applications: Plastic doors and windows, electrical conduits, baseboards, interior wall panels, etc.

• WPC (Wood Plastic Composite) Profiles

Main components: A mixture of wood flour/plant fiber (typically 30% to 70%) and thermoplastic resins (such as PVC, PE, PP), with added coupling agents, stabilizers, and other additives.

Common applications: Outdoor flooring (decking), landscaping, railings, outdoor furniture, wall panels, etc.

Differences Between Profile Extrusion Line:

• Feeding System

PVC: Primarily feeds PVC powder, calcium carbonate, additives, etc. These are typically pre-mixed using a high-speed mixer and then fed into the extruder via a screw metering feeder or vacuum loader.

WPC: Requires precise control of the ratio between wood flour and plastic. The wood flour and plastic usually undergo pre-treatment in a hot-mix/cold-mix system. They are then forcibly and steadily fed into the extruder by a quantitative feeding system (often a volumetric or loss-in-weight force feeder) to ensure uniform mixing and stable feeding.

• Extruder Type

PVC: Mainly uses conical twin-screw extruders or parallel twin-screw extruders. These screw designs provide high shear force and mixing efficiency, suitable for processing PVC powder.

WPC: Parallel twin-screw extruders are more common, especially models with high torque and a large length-to-diameter (L/D) ratio. The screw configuration (e.g., combination of screw elements) needs special design to ensure the wood flour is fully plasticized and uniformly dispersed, while avoiding overheating and degradation of the wood flour.

• Venting System

PVC: A vacuum vent (especially for flexible PVC) might be necessary during production to remove volatile substances and moisture.

WPC: A vacuum venting system is essential. Wood flour contains moisture, which vaporizes during high-temperature plasticization and must be removed through the vacuum vent. Residual moisture can cause bubbles or pores on the profile surface, affecting quality.

• Die, Calibration, and Cooling

PVC/WPC: Both require specialized extrusion dies and vacuum calibration tables/cooling water tanks for profile shaping and cooling. However, the melt viscosity, flow characteristics, and thermal stability of WPC differ from those of pure PVC.

Therefore, the die flow channel design and process parameters for calibration and cooling (such as temperature and calibration vacuum level) need to be adjusted according to the material properties.

The key to WPC profile production line lies in stable forced feeding, efficient vacuum degassing, and a special screw design to handle composite materials containing a large amount of natural fibers. PVC profile production line, on the other hand, focus on high-efficiency plasticizing and compounding.

Video of Profile Production Line:

Why choose Kangju Machinery?

Planning a plant is complex, but partnering with Kangju Machinery simplifies the transition from blueprint to production. With over 15 years of specialized experience in plastic extrusion line, Kangju does not just supply machines; we deliver “Turn-key Intelligence”.

• 15+ Years of Technical Mastery: Proven expertise in pipe / profile / panel / sheet extrusion.
• Customized Molds: Our in-house mold design team uses flow-simulation software. This ensures your PVC wall panels have uniform thickness and a flawless finish from the first meter.
• On-Site Commissioning: We provide global on-site installation and technician training, ensuring your local team is fully capable of maintaining peak production efficiency.

Contact Kangju:

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