Part II Extrusion

1
Wood Plastics Composites Workshop
Thursday, June 15, 2006

• Part II - Extrusion
• Frank W. Maine
• PSA Composites

2
OVERVIEW

• Wood fibres - Preparation for WPCs
• Other ingredients
• Mixing the wood fibre and plastic
• Blending the ingredients
• Feeding the ingredients
• Mixing the ingredients
• Shaping the ingredients
• Downstream processing

3
Characteristics of Natural Fibres

• Contain cellulose
• Hydrophilic
• Contains large quantity of water
• In a composite
• Water prevents good bond (between fibre and
  matrix resin)
• Water results in blowholes and porosity
• Water must be removed

4
Natural Fibres Type

• Woodfibre/flour
• Oak
• Maple
• Spruce
• Pine
• Fir

• Other Natural fibre
• Flax
• Hemp
• Kenaf

5
Water Content of Wood Fibres

• Free water
• Adsorbed water
• Water of constitution

6
Categories of Water Content

• Water
• Green 40 200
• Fibre Saturation Point 25
• Air dry 12 18
• Oven dry 5 10

7
Calculation of Moisture Content

• - Often results in moisture content greater than
  100

8
Water Removal from Wood Fibre

• Experience from particle board and fibreboard
  industry

9
Water Removal from Wood Fibre contd

• Rotary drying

10
Water Removal from Wood Fibre contd

• Flash
• drying

11
Alternatives to Drying

• Woodfibre/plastic concentrate
• Foamed woodfibre/plastic composite

12
Other Ingredients

• Polymer
• Other fillers
• Additives
• Lubricants
• Stabilizers
• Colourants
• Others

13
Other Ingredients

• Polymer
• PE
• PP
• PVC
• Virgin
• Recycled
• Regrind

14
Other Ingredients

• Other fillers
• Calcium carbonate
• Talc
• Mica
• Clay

15
Other Ingredients

• Additives
• Lubricants
• Stabilizers
• Colourants
• Others
• Coupling agents
• Antimicrobial additives

16
MIXING the WF Polymer

• Mixers
• Henschel Mixer
• Gelimat or K-Mixer
• Farrel Continuous Mixer

17
MIXING the WF Polymer

• Mixers
• Henschel Mixer

www.henschel-mixers.com/
18
MIXING the WF Polymer

• Mixers
• Gelimat
• or K-Mixer

www.draiswerke-inc.com/gelimat.htm
19
MIXING the WF Polymer

• Mixers
• Farrel Continuous Mixer

www.farrel.com/
20
MIXING the WF Polymer

• Pelletizers
• Animal Feed pelletizers
• Andritz
• Pallmann

21
MIXING the WF Polymer

• Pelletizers
• Andritz

V-Belt Pellet Mills
Gear-Drive Pellet Mills

• www.andritzsproutbauer.com/pellet-mills.asp

22
MIXING the WF Polymer

• Pelletizers (Agglomerators)
• Pallmann

www.pallmannpulverizers.com/
23
MIXING the WF Polymer

• Extruders
• Twin-screw
• Conical
• Cincinnati Millacron

• http//plastics.milacron.com/Extrusion/woodflour.h
  tm

24
BLENDING the Ingredients

• Gravimetric blenders
• Conair ltwww.conairnet.comgt
• Maguire ltwww.maguire.comgt
• Volumetric feeders
• Dryers
• Motan ltwww.motan.comgt

25
FEEDING the Ingredients

• Gravimetric feeders (loss-in-weight)
• Brabender ltwww.brabenderti.comgt

26
FEEDING the Ingredients

• Major ingredients
• Woodfibre/plastic concentrate
• Polymer
• Regrind
• Other filler concentrate
• Minor ingredients
• Additives

27
MIXING the Ingredients

• Extruders
• Twin-screw extruders (starve fed)
• Conical
• Co-rotating
• Counter-rotating
• Single-screw extruders (flood fed)
• Differences in dispersive and distributive mixing

28
PARALLEL SCREW AXIS
29
MIXING the Ingredients

• Extruders
• Twin-screw extruders
• Co-rotating
• Coperion ltwww.coperion.com/gt
• Entek ltwww.entek-mfg.com/gt
• American Leistritz ltwww.leistritz.com/alec/engt
• Berstorff ltwww.berstorff.de/eng/gt

30
Co-Rotating TS and Hot Melt SS Fiber Composite
System
Side Feeder
Polymer Feed
Co-Rotating TS
Atmospheric Vents
Vacuum Vent
Fiber Feeder
Hot Melt SS
31
Twin-Screw Extruder Simulation
ltwww.ExtrusionTech.comgt
32
MIXING the Ingredients

• Extruders
• Twin-screw extruders
• Counter-rotating
• Davis-Standard ltwww.davis-standard.com/gt
• Krauss-Maffei ltwww.krauss-maffei.de/k/english/gt
• American Leistritz ltwww.leistritz.com/alec/en/gt

33
Counter-Rotating Twin ScrewFiber Composite
Extruder
GP94 Parallel Twin Screw 94mm, 281 L/D, Vented
1 Moisture Maximum allowed in fiber Fiber and
Polymer Pre-mixed
34
MIXING the Ingredients

• Extruders
• Single-screw extruders
• Main stream
• New technology
• Randcastles recirculating mixer
• ltwww.randcastle.comgt

35
SHAPING the Ingredients

• Dies
• Solid profiles
• Hollow profiles
• Shaped profiles
• Callibrators

36
Downstream Processing

• Cooling
• Water cooling
• Air cooling
• Haul-off

37
Downstream Processing

• Secondary operations
• Embossing
• Brushing
• Cutting

38
Preferred Processing Options

• One step
• - make profile directly from raw materials
  (polymer and wood fibre)

39
Preferred Processing Options

• Two step
• - make concentrate
• - extrude profile