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Color Masterbatch Extruder Line: Screw Design & Pelletizing

Colour masterbatch is a dispersion business with a cleaning problem attached: the same line has to make 20% pigment dispersion and then be spotless again in twenty minutes for the next colour. A reference color masterbatch extruder line page from Kerke.

Color Masterbatch Extruder Line — workshop photo 1, Kerke workshop, NanjingColor Masterbatch Extruder Line — workshop photo 1, Kerke workshop, Nanjing
Color Masterbatch Extruder Line — workshop photo 2, Kerke workshop, NanjingColor Masterbatch Extruder Line — workshop photo 2, Kerke workshop, Nanjing
Color Masterbatch Extruder Line — workshop photo 3, Kerke workshop, NanjingColor Masterbatch Extruder Line — workshop photo 3, Kerke workshop, Nanjing
Color Masterbatch Extruder Line — workshop photo 4, Kerke workshop, NanjingColor Masterbatch Extruder Line — workshop photo 4, Kerke workshop, Nanjing
Color Masterbatch Extruder Line — workshop photo 5, Kerke workshop, NanjingColor Masterbatch Extruder Line — workshop photo 5, Kerke workshop, Nanjing
Color Masterbatch Extruder Line — workshop photo 6, Kerke workshop, NanjingColor Masterbatch Extruder Line — workshop photo 6, Kerke workshop, Nanjing
Running video — Color Masterbatch Extruder Line, Kerke workshop
Running video — Color Masterbatch Extruder Line, Kerke workshop

Quick answer

Colour masterbatch lines run 20–60% pigment on a co-rotating twin screw with L/D 40–48 and a dispersive mixing block, pelletized by water ring or strand. Output 100–1,200 kg/h; changeover between colours is the real constraint, not throughput.

40–48screw L/D
80–120mesh filtration
150–250 kg/hKTE-65B, general colour

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

What sets the limit

Pigment powder, carrier and wax are metered separately by gravimetric feeders, melted in barrel 1–2, dispersed through a 45°/5/45° mixing block, filtered at the die and pelletized. Fast colour change depends on barrel access and a split barrel design, not on screw speed.

Table 1. Key parameters for color masterbatch extruder line. Reference values — confirm on a material trial.
ParameterValue / range
Pigment loading20–60% (TiO2 up to 70% on white lines)
L/D40–48
Temperature150–200 °C depending on carrier
PelletizingWater ring / strand / underwater
Output (reference)100–1,200 kg/h
ModelKTE-50B to KTE-75B

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 150–200 °C depending on carrier.
  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 packingWater ring / strand / underwater; 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. Judging dispersion by eye

Judging dispersion by eye — specify a filter-pressure value (bar) and a let-down test instead.

2. Under-specifying the feeder: pigment at 0.5% of throughput needs ±0.3% accuracy, which rul

Under-specifying the feeder: pigment at 0.5% of throughput needs ±0.3% accuracy, which rules out single-screw volumetric feeders.

3. Adding kneading blocks until dispersion feels safe

Adding kneading blocks until dispersion feels safe — every extra block adds 3–6% specific energy and raises melt temperature; validate the let-down test at 40D before paying for 48D.

FAQ

How fast is a colour change?

2–4 hours for a full change on a split-barrel machine with purging compound. Customers running many small lots usually buy two smaller lines rather than one large one.

Water ring or strand for colour?

Water ring for high pigment and thin strands; strand for low-volume, high-value colours where pellet shape matters less than cleaning.

What output can you guarantee for this application?

The reference band is 100–1,200 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.

Color masterbatch extruder line — the short version

Note on color masterbatch extruder line: 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