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Application · Specialty & Low-Temperature

Hot Melt Adhesive Compounding: Low Shear, Underwater Cutting

Hot melt is 120–160 °C, low shear and vacuum-degassed: high shear or 170 °C+ oxidizes the resin and turns the adhesive brown, and trapped bubbles break the glue line. A reference hot melt adhesive compounding page from Kerke.

Hot Melt Adhesive Compounding — workshop photo 1, Kerke workshop, NanjingHot Melt Adhesive Compounding — workshop photo 1, Kerke workshop, Nanjing
Hot Melt Adhesive Compounding — workshop photo 2, Kerke workshop, NanjingHot Melt Adhesive Compounding — workshop photo 2, Kerke workshop, Nanjing
Hot Melt Adhesive Compounding — workshop photo 3, Kerke workshop, NanjingHot Melt Adhesive Compounding — workshop photo 3, Kerke workshop, Nanjing
Hot Melt Adhesive Compounding — workshop photo 4, Kerke workshop, NanjingHot Melt Adhesive Compounding — workshop photo 4, Kerke workshop, Nanjing
Hot Melt Adhesive Compounding — workshop photo 5, Kerke workshop, NanjingHot Melt Adhesive Compounding — workshop photo 5, Kerke workshop, Nanjing
Hot Melt Adhesive Compounding — workshop photo 6, Kerke workshop, NanjingHot Melt Adhesive Compounding — workshop photo 6, Kerke workshop, Nanjing
Running video — Hot Melt Adhesive Compounding, Kerke workshop
Running video — Hot Melt Adhesive Compounding, Kerke workshop

Quick answer

Hot melt adhesives (EVA, APAO, PA, PSA) are compounded at low temperature and low shear on a twin screw with L/D 36–44 and underwater pelletizing to prevent blocking. Output 200–1,200 kg/h. Thermal degradation, not dispersion, is the limiting factor.

120–160 °Cprocess temperature
vacuumdegassing
underwaterpelletizing

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

What sets the limit

Resin, tackifier and wax are melted gently, mixed without high shear, filtered and underwater pelletized with chilled water to keep pellets free-flowing.

Table 1. Key parameters for hot melt adhesive compounding line. Reference values — confirm on a material trial.
ParameterValue / range
MaterialsEVA, APAO, polyamide, PSA
Temperature100–160 °C, tight control
L/D36–44
PelletizingUnderwater (prevents blocking)
Output (reference)200–1,200 kg/h
ModelKTE-50B, KTE-65B

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 100–160 °C, tight control.
  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 packingUnderwater (prevents blocking); 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. Overheating the tackifier causes yellowing and loss of tack.

Overheating the tackifier causes yellowing and loss of tack.

2. Strand pelletizing hot melt gives one fused block in the bag.

Strand pelletizing hot melt gives one fused block in the bag.

3. Open feeding that lets hot tackifier oxidise

Open feeding that lets hot tackifier oxidise — the colour drifts from water-white to yellow and the customer sees it in the finished book; keep the hopper sealed and the melt covered.

FAQ

Why underwater pelletizing?

Hot melt pellets are soft at room temperature; only underwater cutting with chilled water gives free-flowing pellets.

Can the line handle pressure-sensitive adhesives?

Yes, with a low-shear screw and a die designed for high viscosity; PSA is the most temperature-sensitive product on this platform.

What output can you guarantee for this application?

The reference band is 200–1,200 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.

Hot melt adhesive compounding — the short version

Note on hot melt adhesive compounding: 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