Calendering · Roll Forming · PVC Film
Calendering — Thermoplastic Sheet and Film
Calendering is the dominant process for PVC sheet and film — your vinyl flooring, the blister sheet around your medicine, the leather-look upholstery in your car. The 4–5 counter-rotating rolls in a calendering line are essentially giant precision rolling mills for plastic.
Calendering Line Components
Modern calendering line elements:
| Component | Function |
|---|---|
| Internal mixer / Banbury | PVC dry-blend mixing + heating to soft mass |
| Two-roll mill or planetary extruder | Pre-heat + initial sheet forming |
| Calendering stack (4–5 rolls) | Final gauge + surface quality |
| Embossing roll | Texture / pattern imprinting |
| Cooling rolls | Quench to solid sheet |
| Winder | Roll up finished sheet |
| Edge trim + slitter | Final dimensioning |
PVC Calendered Products
Major output categories:
| Product | PVC type | Thickness |
|---|---|---|
| Vinyl flooring (sheet) | PVC-P with plasticizer + filler | 1.5–3 mm |
| Floor tile (LVT) | PVC-P + filler, multi-layer | 2–5 mm total |
| Pharma blister sheet | Rigid PVC | 200–400 µm |
| Decorative film | PVC-P thin film | 100–250 µm |
| Auto upholstery (leather-look) | PVC-P + texture emboss | 0.5–1.5 mm |
| Wall covering | PVC + texture | 0.4–1.0 mm |
| Pool liner | PVC-P UV-stable | 0.6–1.5 mm |
| Inflatable structures | PVC-P + woven backing | 0.5–1.5 mm |
FAQ — Frequently Asked Questions
Calendering vs extrusion sheet?
Calendering: better surface quality, more economical for high volume (>1000 kt/y), better thickness uniformity for thin sheet (<2 mm), PVC-friendly (low shear). Extrusion: lower capital cost, lower production threshold (50–500 kt/y), simpler for engineering plastics (ABS, PC), better for thick sheet (>3 mm). Industry split: PVC sheet ~70 % calendered, ABS/PC sheet ~80 % extruded.
Why is PVC ideal for calendering?
PVC has high melt viscosity (high shear sensitive), benefits from low-shear roll process. Calendering uses heat + slow shear vs extrusion's high shear. Result: less thermal degradation, less HCl release. Plus: PVC dry-blend (powder + plasticizer + stabilizer) can be fed directly to mixer; no compounding/pelletizing step. End-to-end energy and capital savings.
Calendering line size?
Standard line throughput 1500–5000 kg/h. Roll length 1.2–2.5 m (sheet width). Roll diameter 0.6–1.2 m. Total line length 50–100 m. Capital cost: €15–50M per line. Major producers: Tarkett, IVC Group, Forbo for flooring; Bayer/Renolit for sheet; Klöckner Pentaplast for blister film.
Calendering future — declining?
Calendering volume stable or slowly declining. Reasons: PVC volume declining in EU (regulatory + recycling concerns); LVT vinyl tile growing (still calendered); extrusion gaining for new applications. Calendering retains niche where economy of scale + PVC chemistry intersect (flooring, pharma blister, decorative film). Sustainability trend: calendered TPO sheet for auto interior replacing PVC.
See also: PVC-P · Extrusion · Construction · 🇩🇪 German full version