Cling Film Manufacturing Process: How PVC & PE Cling Wrap Is Made

PVC Cling Film Production: The Calendering Process

PVC cling film is produced by calendering — a process that transforms PVC resin + plasticisers + additives into a uniform thin film.

Stage 1: Raw Material Mixing

• PVC resin (S-PVC, K-value 62–65 for film grade)
• Plasticisers (DINP, DOTP, or ATBC — food-grade only)
• Stabilisers (Ca/Zn for food-grade; avoid lead stabilisers)
• Processing aids and anti-fog agents

Mixed in high-speed mixers at 100–120°C until fully blended into a dry powder compound. This compound determines the final film’s cling strength, transparency, and flexibility.

Stage 2: Calendering

The compound feeds through a series of heated rollers (calender):

• Roller temperature: 180–200°C
• Gap between rollers progressively decreases
• Film exits at target thickness (8–50 microns)
• Thickness tolerance: ±2µm (SUNWRAP standard)

Stage 3: Cooling & Winding

Film passes through cooling rollers, then wound onto master rolls (1,000–5,000 meters). Quality checks: thickness uniformity, transparency, pinhole detection.

Stage 4: Slitting & Packaging

Master rolls are slit to customer width, re-wound to specified length, inserted into color boxes with cutters.

PE Cling Film Production: Blown Film Extrusion

PE cling film is fundamentally different — produced by blown film extrusion, no plasticisers needed.

Stage 1: Resin & Additive Blend

• LDPE (Low-Density Polyethylene) as base resin
• LLDPE (Linear Low-Density Polyethylene) for strength
• PIB (Polyisobutylene) or EVA for cling/tackiness
• Anti-fog additive for condensation control

No plasticisers = no plasticiser migration concerns = preferred for EU and health-conscious markets.

Stage 2: Blown Film Extrusion

Resin melted in extruder (180–220°C), forced through circular die. Air inflates the molten tube into a bubble. Bubble diameter determines film width. Cooling ring solidifies the film.

Stage 3: Collapsing & Winding

Bubble collapsed into flat tube, wound onto master rolls. PE film is naturally more hazy than PVC — clarity depends on resin grade and processing precision.

Quality Control Checkpoints

Stage	Test	Standard
Raw material	Resin certification	Supplier CoA
In-process	Thickness gauge	±2µm across web
In-process	Optical inspection	Pinhole/contamination detection
Finished roll	Length verification	±2% of stated length
Finished roll	Cling strength	Peel test >0.3 N/25mm
Finished roll	Migration test	<10 mg/dm²
Final QA	Visual inspection	AQL 2.5 sampling

PVC vs PE: Production Comparison

Factor	PVC Calendering	PE Blown Film
Clarity	Crystal clear	Slightly hazy
Cling strength	Excellent	Good (needs tackifier)
Plasticisers	Required	Not required
Temperature resistance	-10°C to 80°C	-30°C to 100°C
Environmental perception	Challenged in EU	Preferred “green” choice
Cost	Lower	~15% higher

FAQ

Q: Why does some cling film stick better than others? Cling strength depends on plasticiser formulation (PVC) or tackifier additives (PE). Cheap films use less/migrating plasticisers = poor cling. SUNWRAP’s formulation is optimized for cling strength at both refrigerated and room temperature.

Q: Can I visit the factory to see production? Yes. SUNWRAP welcomes factory visits. See the calender line, slitting operation, and QC lab in person. Factory is 40km from Ningbo airport.