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Application · Specialty & Low-Temperature

Powder Coating Extrusion: 80–120 °C Low-Temp Process

Powder coating is extruded cold on purpose. Above 120–130 °C the resin starts to gel, and gel inside the barrel means a stopped line and a chisel. A reference powder coating extrusion page from Kerke.

Powder Coating Extrusion — workshop photo 1, Kerke workshop, NanjingPowder Coating Extrusion — workshop photo 1, Kerke workshop, Nanjing
Powder Coating Extrusion — workshop photo 2, Kerke workshop, NanjingPowder Coating Extrusion — workshop photo 2, Kerke workshop, Nanjing
Powder Coating Extrusion — workshop photo 3, Kerke workshop, NanjingPowder Coating Extrusion — workshop photo 3, Kerke workshop, Nanjing
Powder Coating Extrusion — workshop photo 4, Kerke workshop, NanjingPowder Coating Extrusion — workshop photo 4, Kerke workshop, Nanjing
Powder Coating Extrusion — workshop photo 5, Kerke workshop, NanjingPowder Coating Extrusion — workshop photo 5, Kerke workshop, Nanjing
Powder Coating Extrusion — workshop photo 6, Kerke workshop, NanjingPowder Coating Extrusion — workshop photo 6, Kerke workshop, Nanjing
Running video — Powder Coating Extrusion, Kerke workshop
Running video — Powder Coating Extrusion, Kerke workshop

Quick answer

Powder coating production is the one extrusion line that does not pelletize: resin, curing agent, pigment and filler are compounded at 90–120 °C, then chill-rolled into flakes and milled. Output 200–1,000 kg/h. Preventing premature reaction is the whole design goal.

80–120 °Cmelt temperature
30–36screw L/D
800–1,000 kg/hKTE-95

Workshop photos and a running video — shot on our own lines, not stock images.

What sets the limit

Pre-mixed powder is compacted and melted just enough to disperse, extruded through a flat die onto a chilled roll, broken into flakes and later milled to powder.

Table 1. Key parameters for powder coating extrusion line. Reference values — confirm on a material trial.
ParameterValue / range
MaterialsEpoxy, polyester, hybrid, acrylic
Temperature90–120 °C (below curing onset)
DownstreamChill roll + flake breaker (no pelletizer)
Output (reference)200–1,000 kg/h
ModelKTE-50B, KTE-65B with chill roll
L/D32–40

Output figures are measured on the reference material stated above. Filler grade, bulk density and moisture move output by ±15% — that is why every quotation we issue is tied to a trial report.

Process flow, step by step

  1. FeedingLoss-in-weight dosing of polymer and filler; side feeder or liquid injection where the formulation needs it.
  2. Melting and dispersingScrew geometry with 45°/90° kneading blocks; barrel profile 90–120 °C (below curing onset).
  3. DevolatilizationVacuum vent at −0.06 to −0.09 MPa removes moisture and volatiles before the die.
  4. Pressure build-upThrottle or discharge section stabilises die pressure; a melt pump where gauge control matters.
  5. Pelletizing and packingdie-face or strand pelletizing, see the pelletizing page; then centrifugal dryer, vibrating screen and bagging.

Equipment configuration

Table 2. What the line is made of, and why each part is specified that way.
StageEquipmentWhy this choice
Main machineCo-Rotating Twin Screw ExtruderArchitecture follows the filling level and the mixing duty, not the required tonnage.
Screw geometryBuilding-block elements, W6Mo5Cr4V2, bimetallic linerWear package for abrasive filler; mixing blocks only where dispersion demands them.
FeedingLoss-in-weight feeder, side feeder where neededRecipe accuracy: ±0.5% short term on the weighed component.
PelletizingPelletizing systemChosen by polymer and filler ceiling — water contact is the deciding column.
DownstreamCentrifugal dryer, vibrating screen, baggingFines below 2% and moisture below the specification of your downstream process.

Output by model

Table 3. Co-rotating twin screw KTE — reference output. Full range on the machine page.
ModelDia. (mm)Speed (rpm)Motor (kW)Torque (N·m)Output (kg/h)
KTE-50B50.5500–60055–752×52580–200
KTE-50D50.5300–80075–902×860100–300
KTE-52B51.4500–60055–752×72080–200
KTE-52D51.4500–60075–1102×1050100–400
KTE-65B62.4500–60090–1102×860200–450
KTE-65D62.4300–800132–1602×1530350–600
KTE-75B71500–600132–1602×1530300–800
KTE-75D71300–800200–3152×2100500–1000
KTE-85B85500–600220–3152×2100550–1000
KTE-95B93500–600250–3152×3000800–1500
KTE-95D93500–800315–5002×48001000–2000
KTE-135B135500–600315–5002×48001500–3000
KTE-135D135500–800500–10002×78001500–4000

Three mistakes that cost the most

1. Any hot spot initiates curing; the flake becomes insoluble and the coating fails.

Any hot spot initiates curing; the flake becomes insoluble and the coating fails.

2. Long residence time has the same effect as high temperature.

Long residence time has the same effect as high temperature.

3. Colour change without a validated purge

Colour change without a validated purge — flake cross-contaminates instantly; dedicate a screw or a documented purge protocol between dark and light shades.

FAQ

Why not pelletize?

Pellets would need cooling in water and re-milling; the industry standard is flake from a chill roll.

Can you supply the milling stage?

We supply the extrusion and chill-roll section; milling and sieving are usually sourced locally to the customer.

What output can you guarantee for this application?

The reference band is 200–1,000 kg/h, measured on the stated material. We quote a guaranteed figure only after a trial on your own material, because filler grade, bulk density and moisture move output by ±15%.

Can we run our material before ordering?

Yes — send 25–50 kg. We return pellets, a running video and a report with temperatures, screw speed, feeder settings and output per hour. The trial is free; you cover the freight.

What is the delivery time?

30–45 working days for standard configurations, 45–70 for custom screw geometry and ODM work. Voltage and frequency are built for the destination country.

Where these numbers come from

Parameters are taken from the Kerke product parameter table and the product master data sheet, and cross-checked against commissioning records for lines in the same application. Formulations and temperature windows are typical industry values, not a recommendation for your specific compound — every figure marked reference must be confirmed on a material trial before it becomes a contractual number.

Reviewed by the Kerke process team, Nanjing. Page updated 6 November 2026.

Tell us your material — we will tell you the line

Send 25–50 kg and we run it on our lab extruder: pellets, running video and a capacity report back in 3–7 days.

Powder coating extrusion — the short version

Note on powder coating extrusion: the numbers above are reference ranges from Kerke's own trial runs, not catalogue promises. Screw geometry, wear package and pelletizing method are set on the trial bench first, so the output you compare is the output you get. If your grade is not in the tables, send it — the closest configuration is usually a change of screw set, not a different machine.

Related on this site: Machine range: KTE-50B to 135D · Pelletizing methods compared · quotation and free trial · Wikipedia: Masterbatch