All of the raw material such as polymers, fillers, and additives are mixed or split feed, reacted, and devolatilized in a high-speed co-rotating Twin Screw Extruder and directly made into a final product such as sheet/film, bypassing pelletizing.

Why Direct Extrusion

Traditional Process for Film/Sheet:

  • For simple formula, such as PE with small quantity masterbatch/additives
    The process: premix all component and add into the single screw extruder for sheet/film extrusion.
  • For complicated formula, such PP with 40% filler/wood fiber
    The process: the first step is doing filler or wood plastic compounding by twin screw extruder, then premix all components and add into the single screw extruder for sheet/film extrusion.
  • For water sensitive material, such PET/PA
    The process: 3-5 hours for predrying is necessary before extrusion by single screw extruder.

Disadvantages about Traditional Process:

  • More energy consumption for predry or two stage process or single screw extruder
  • More man power, factory space and investment
  • Less dispersion quality for additive and polymer in different MFI
  • Over heating and shearing for nature wood fiber
  • Over shearing for Glass fiber in D-LFT process
  • Polymer degradation in two step process

Experience in Direct Extrusion

We have done many projects by Direct Extrusion which can solve one or several problem from the traditional process. We would like to share these experience in the following Direct Extrusion:

  • PP Compounding with Talc and Sheet Extrusion
  • PP Compounding with Wood Fiber and Sheet Extrusion
  • HDPE Waterproof Sheet
  • BOPP/BOPA Film Extrusion
  • EVA Film for Solar Cell Encapsulation

1) PP Compounding with Talc and Sheet Extrusion

PP Compounding with Talc and Sheet Extrusion

Basic Formula:
COPP Compounding with 40% Talc and 2% Color masterbatch.

Sheet Specification:
Width 850mm
Thickness 0.6–1.0mm
Linear speed: 10–17m/min
Maximum output: 900kg/h

Application:
thermoforming for food packing

Process:
Vacuum loading and split feeding system to avoid the dust pollution on final sheet.
PP and Color masterbatch are feed into the first barrel.
Talc is separately feed into two side force feeder.
There is no lubricant additive because of the final sheet is used for hot food packing. When the output of extruder more than 600kg, the melting temperature will increase a lot due to friction. USEON supply the special cooler and screw design to reduce the melting temperature before T-Die.
The sheet extrusion can also joint with thermoforming line, bypassing winder, so no need preheating system for thermoforming, it will save more energy and man power.

USEON can supply the completely DIRECT EXTRUSION line from feeding to thermoforming.

2) PP Compounding with Wood Fiber and Sheet Extrusion

Basic Formula:
PP Compounding with 40% wood fiber, color masterbatch and additives

Sheet Specification:
Width 1400 –1600mm
Thickness 0.8–1.5mm
Linear speed: 4–10m/min
Maximum Output: 600kg/h

Sheet Application:
Protection layer of wall and ceiling panel

Process:
PP and Color masterbatch are feed into the first barrel.
Wood fiber premix additives then feed into side force feeder. PP melting temperature is more than 190℃, so it is necessary to feed wood fiber after PP melt.
USEON supply screw design to avoid over shearing but still good mixing without reducing the length of fiber.
Due to low fluidity of wood fiber, USEON develop special gear pump and suggest one type lubricant for inner lubricant.
The final sheet will be sticky on the nature wood panel for waterproof. So need Non woven fabric coating for both side.

USEON can supply the completely DIRECT EXTRUSION line from feeding to stacker.

3) HDPE Waterproof Sheet

Basic Formula:
HDPE Compounding with color masterbatch and additives
Sheet specification:
Width 1200 mm ± 2 mm
Thickness 0.65 – 1.40 mm ±0.05mm
Linear speed: 8–17m/min
Maximum output: 800kg/h

Application:
Floor Moisture Barrier & Roofing Underlayments

Process:
Vacuum loading — gravimetric feeding — twin screw extruder for sheet extrusion.

Twin Screw Extruder Advantage:
Comparing to single screw extruder, twin screw extruder have the following advantages:

  • Saving energy up to 30%
  • Better dispersion performance
  • Less waste for changing color due to self-cleaning effect
  • Less residence time leads to less polymer degradation

USEON can supply the completely DIRECT EXTRUSION line from premixing to winder.

4) BOPP/BOPA Film Extrusion

Basic Formula:
PP/PA compounding with additives (anti-slip, anti-static, anti-oxidant etc.)

Application:
For all kind of packaging

Process:
Traditional process is two sets of single extruder with series connection to get more output.
We change two sets of single screw extruder into one set of twin screw extruder.

Advantages:
Saving energy up to 30%: the same motor 1200KW, we can get the output 5500kg/h, but single screw extruder get maximum 4200kg/h.
Less residence time leads to less polymer degradation.
Better dispersion performance leads to less percentage of additives
Better degassing performance, special for BOPA, predrying step can be omitted.
Two model extruder with high torque gearbox is special designed for this application.

Technical Specifications of Extruder:

ModelDiameter
(mm)
Max. Speed
(rpm)
Motor
(kW)
L/DOutput
(kg/hr)
SAT-X1501504001200365000-6000
SAT-X1751753002000367000-10000

5) EVA Film for Solar Cell Encapsulation

EVA Film for Solar Cell Encapsulation

Basic Formula:
EVA (TPC MA-10 with VA content <=33), additives in liquid or powder form

Sheet Specification:
Width 2300 mm
Thickness 0.2~0.9mm (with accuracy +/-0.02mm)
Shrinking rate: <3%
Linear speed: > 6m/min
Maximum Output: 500kg/h

Application:
Solar Cell Encapsulation

Process:
EVA and additive are premixed and feed into the first barrel by loss in weight feeder.
Liquid additives is feed into the 4th barrel by by loss in weight feeder.
Need special screw design to get good mixing and avoid over shearing.
Better degassing performance.
Hot calibration system to reduce the shrinking rate.
Automatic winder with Tension control system (tension range:10~100N).

USEON can supply the completely DIRECT EXTRUSION line from feeding to winder and including the on-line crushing system.

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