PVC (Polyvinyl Chloride): Applications, Advantages & Injection Molding Guide

PVC, or Polyvinyl Chloride, is a highly versatile thermoplastic known for its flame retardancy, chemical resistance, and affordability. It is widely used in both rigid and flexible forms across industries like construction, healthcare, automotive, and consumer goods.

What Is PVC?
PVC is made through the polymerization of vinyl chloride monomer. It is naturally rigid but can be made flexible with the addition of plasticizers. It is one of the most widely produced plastics globally, available in rigid (uPVC) and flexible (fPVC) grades for diverse applications.

Key Applications of PVC
Construction
– Pipes and fittings for water and drainage
– Vinyl siding and window profiles
– Wall coverings and flooring

Medical
– Blood bags and IV tubing (flexible)
– Medical packaging and trays
– Catheters and oxygen masks

Automotive
– Cable insulation and dashboard skins
– Door panels and seals
– Underbody protection coatings

Consumer Products
– Cards (e.g., credit cards), toys, and inflatable items
– Shower curtains and flooring
– Garden hoses and boots

Electronics
– Wire insulation and sheathing
– Electrical conduit and housings

Advantages of PVC
– Excellent flame retardancy (self-extinguishing)
– Good chemical and weather resistance
– Low permeability to gases and liquids
– Strong dielectric properties for electrical applications
– Easily bonded, welded, or solvent joined
– Wide range of hardness and flexibility with additives

Injection Molding Guidelines for PVC

1. Drying Requirements
PVC generally does not need drying unless stored improperly.
– Drying temperature: 70–80 °C (optional)
– Time: 1–2 hours if necessary

2. Melt and Mold Temperatures
– Melt temperature: 185–205 °C (avoid exceeding 210 °C to prevent degradation)
– Mold temperature: 20–50 °C
– Use a well-ventilated mold to allow gas release

3. Injection Pressure & Speed
– Pressure: Up to 1500 bar depending on wall thickness
– Speed: Use slow to moderate speed to prevent thermal degradation

4. Runner and Gate Design
– Submarine, fan, or edge gates commonly used
– Gate diameter: ≥1 mm to ensure smooth flow
– Avoid sharp corners to minimize stress concentration

Common Molding Challenges
– Decomposition: PVC can degrade into hydrochloric acid if overheated
– Burning/smoking: Reduce barrel temps and avoid dead spots in the barrel
– Weld lines: Improve venting and increase mold temperature
– Yellowing: Caused by overheating or long residence time

Final Thoughts
PVC is a dependable and economical choice for both structural and flexible plastic products. It performs exceptionally in applications requiring flame retardancy, chemical resistance, and weatherproofing.
Careful processing is essential to avoid degradation and discoloration. By maintaining tight control over temperature and residence time, PVC can deliver safe, consistent, and long-lasting molded parts.
Need help with PVC formulation selection or safe processing strategies? Our experts are here to assist with materials and mold design recommendations.