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refreshing extrusion technology
Dispersion and Mixing Characteristics of High Volume and High Torque Twin Screw Extrudersand optimised line layoutMichael Thummert – Head of MarketingLeistritz Extrusionstechnik GmbH, Germany
refreshing extrusion technology
2 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Agenda
Factors that have an impact on pigment dispersion and mixing Extruder Configuration Processing Parameters Line Configuration
Dispersion Study with BASF
refreshing extrusion technology
4 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Energy Balance in the Twin Screw ExtruderPdrive = drive power
Qheat = heating power
Ḣout= enthalpyof product
Ḣin = enthalpy input
Pshafts
Qcool = Coolingenergy
Loss due togearbox and frequency converter
.
.
Ḣevap = Evaporation
refreshing extrusion technology
5 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Energy Balance in the Twin Screw ExtruderIntroduction of power into the extruder
000
meltingnevaporatiobarrelshafts HHQVUP
VTTcmVUP inoutvTTcm
shafts
inoutv
vV
v
kgkWhe
shafts
v
shaftsinout cm
Vcm
PcmVP
TT
1
vvinout cc
eTT
refreshing extrusion technology
6 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Energy Balance in the Twin Screw Extruder
Specific energy input
Es= Mact/Mmax * Nact/Nmax * Pnom kW * (0,97)/output kg/h
Es= specific energy inputMact= actual torque Mmax= maximum torque Nact= actual speedNmax= maximum speedPnom= nominal power
The specific energy input is specified in kWh/kg.
refreshing extrusion technology
7 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Energy Balance in the Twin Screw ExtruderComparison of gearboxes by means of the torque factor [ f ]: unit for power density independent from the extruder size
fMd = T / a 3 [ Nm / cm 3 ] (1)
(1) source: Schenkel, G.: Kunststoff-Extrudertechnik. München, Wien, New York, Carl Hanser -Verlag, 1963
refreshing extrusion technology
8 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Comparison of Energy InputHP Standard Screw ZSE HP
HP=XX identical screw for the ZSE MAXX Series
refreshing extrusion technology
9 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Residence Time Distribution
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
1,8
0 20 40 60t / s
E(t
) / s
-1
HPXX=HPXX+XX (Igel)XX (Rück)
SEI [kWh/kg]
0,276
0,253
0,275
0,254
0,399
of ZSE HP und ZSE MAXX E (t) :
refreshing extrusion technology
11 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Four Major Topics for Processing ParametersThere are four main problems that canoccur while running a line:
Volume problems
Air problems
Temperature problems
Torque problems
refreshing extrusion technology
12 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Volume problems
ventingdegassing feeding zone
feeding
polymer
meltingside feeder
additives/powder
mixing
kneading
mixing
sealing
pressure
building zone
gravimetricfeeder #2
gravimetric feeder #1
Pressure (bar)
How is the material stream split up? Screw geometry / process setup Screw speed
refreshing extrusion technology
13 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Air problems
ventingdegassing feeding zone
feeding
polymer
meltingside feeder
additives/powder
mixing
kneading
mixing
sealing
pressure
building zone
gravimetricfeeder #2
gravimetric feeder #1
Pressure (bar) Where are seals? Where are venting ports? Does vacuum port work?
refreshing extrusion technology
14 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Temperature problems
ventingdegassing feeding zone
feeding
polymer
meltingside feeder
additives/powder
mixing
kneading
mixing
sealing
pressure
building zone
gravimetricfeeder #2
gravimetric feeder #1
Pressure (bar)Energy Input
too much energy input by the screw too high screw speed Check specific energy input
refreshing extrusion technology
15 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Torque problems
ventingdegassing feeding zone
feeding
polymer
meltingside feeder
additives/powder
mixing
kneading
mixing
sealing
pressure
building zone
gravimetricfeeder #2
gravimetric feeder #1
Pressure (bar)Energy Input
too low screw speed Material viscosity – temperature too low Check specific energy input
refreshing extrusion technology
20 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Extruder Setup ZSE MAXX Premix
Option:Setup with LSB as
Side Vent
Option:Setup with LSB as
Side Vent
Large Feed OpeningLarge Feed OpeningOption:2nd closed barrel when
using a fine screen or UWP
Option:2nd closed barrel when
using a fine screen or UWP
2-4 barrels for dispersion depending on pigmentand neccessary quality
2-4 barrels for dispersion depending on pigmentand neccessary quality
PremixPremix
refreshing extrusion technology
21 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Extruder Setup ZSE MAXX Premix Facts Large feed opening for more volume in the feed zone
3 barrels for melting and wetting of the mix
Atmospheric opening can be done with a side feeder less dust!
Depending on desired quality: 2-4 barrels for dispersion
Optional second barrel at the discharge zone in order to create enough
pressure for the use of fine screens and underwater pelletizers
Process length between 36L/D and 48L/D
Screw speeds up to 1,200 rpm
OD/ID = 1.66
Torque factor 15 Nm/cm³ for MB with technical polymers
refreshing extrusion technology
22 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Extruder Setup ZSE MAXX Split Feed
PigmentPigment PolymerPolymer
Large side feederfor high volume
pigment
Large side feederfor high volume
pigment
Large Feed OpeningLarge Feed OpeningOption:2nd closed barrel when
using a fine screen or UWP
Option:2nd closed barrel when
using a fine screen or UWP
2-4 barrels for dispersion depending on pigmentand neccessary quality
2-4 barrels for dispersion depending on pigmentand neccessary quality
refreshing extrusion technology
23 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Extruder Setup ZSE MAXX Split Feed Facts Larger side feeder for higher mass flow when feeding pigments
Wetting zone with forward venting
Process length between 44L/D and 52L/D
Screw speeds up to 1,200 rpm
Do/Di = 1.66
Torque factor 15 Nm/cm³ for MB with technical polymers
refreshing extrusion technology
24 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
New Barrel for ZSE MAXX
Large Feed Openingapprox. 50% increase!Large Feed Opening
approx. 50% increase!
refreshing extrusion technology
25 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
Twin Operation of the Extrusion LineTwo control panels facilitate control of the line from
two positionsTwo control panels facilitate control of the line from
two positions
refreshing extrusion technology
28 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
28
Dispersion study with BASF
Our Goals:
Transfer of the dispersion properties to the extrusion process
Effects of the dispersion characteristics on:Homogenizing / dispersive pre-mixingFree volume of the extruder (HP / MAXX)Operating parameters (rpm, fill level)
General parameters for optimally dispersed pigments
refreshing extrusion technology
29 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
29
Process variables
Pre-mixingHomogenizing mixing (tumble mixing)Mixing with fast running chopper
Leistritz ZSE 18 HP
Leistritz ZSE 18 MAXXFor both machines:
300, 600, 900 rpmPartially filled and almost filled screwsthroughput limited for the ZSE 18 HP: 3-12 kg/h
Constant:10% MB in LDPE MFI 25, 110°C, premix-screw design
refreshing extrusion technology
30 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
30
Analysis – qualitative overviewPaliotol Yellow K 2270
80
85
90
95
100
105
110
115
120
125
130
135
140
0 30 0 6 00 900 12 00
Ex trud er [rpm]
Co
lou
r St
reng
th [%
]
HP , tumble , part ly filledHP , tumble , filledHP , dispers ive, partly filled
HP , dispers ive, filledM AX X, tumble, part ly f illedM AX X, tumble, filled
M AX X, dispersive , partly filledM AX X, dispersive , filled
Cromophtal Yellow 2GF
8 0
8 5
9 0
9 5
10 0
10 5
11 0
11 5
12 0
12 5
13 0
13 5
14 0
0 30 0 6 00 90 0 12 00
Ex trud er [rpm]
Co
lou
r S
tren
gth
[%
]
H P, tumble , part ly f illedH P, tumble , filledH P, dispersive , partly filled
H P, dispersive , filledM AX X, tumble, par tly filledM AX X, tumble, filled
M AX X, dispers ive, part ly filledM AX X, dispers ive, filled
Cromophtal Yellow 3GNP
8 0
8 5
9 0
9 5
10 0
10 5
11 0
11 5
12 0
12 5
13 0
13 5
14 0
0 3 00 600 90 0 1 200
Ex trud er [rp m]
Co
lour
Str
engt
h [%
]
H P, tumble, par tly filledH P, tumble, filledH P, dispers ive, partly filled
H P, dispers ive, filledM AX X, tumb le , par tly filledM AX X, tumb le , filled
M AX X, dispersive , part ly f illedM AX X, dispersive , filled
Cromophtal Red BNFP
8 0
8 5
9 0
9 5
10 0
10 5
11 0
11 5
12 0
12 5
13 0
13 5
14 0
0 3 00 600 90 0 1 200
Extrud er [rp m]
Co
lour
Str
engt
h [%
]
H P, tumble , par tly filledH P, tumble , filledH P, dispers ive , part ly f illed
H P, dispers ive , filledM A XX, tumb le, p ar tly filledM A XX, tumb le, f illed
M A XX, dispers ive, par tly filledM A XX, dispers ive, filled
Cromophtal Pink PT
80
85
90
95
100
105
110
115
120
125
130
135
140
0 30 0 6 00 900 12 00
Ex trud er [rpm]
Co
lou
r St
reng
th [%
]
HP , tumble , part ly filledHP , tumble , filled
HP , dispers ive, partly filledHP , dispers ive, filledM AX X, tumble, part ly f illed
M AX X, tumble, filledM AX X, dispersive , partly filledM AX X, dispersive , filled
Paliogen Red Violet K 5011
8 0
8 5
9 0
9 5
10 0
10 5
11 0
11 5
12 0
12 5
13 0
13 5
14 0
0 30 0 6 00 90 0 12 00
Ex trud er [rpm]
Co
lou
r S
tren
gth
[%
]
H P, tumble , part ly f illedH P, tumble , filled
H P, dispersive , partly filledH P, dispersive , filledM AX X, tumble, par tly filled
M AX X, tumble, filledM AX X, dispers ive, part ly filledM AX X, dispers ive, filled
Cromophtal Violet GT
8 0
8 5
9 0
9 5
10 0
10 5
11 0
11 5
12 0
12 5
13 0
13 5
14 0
0 3 00 600 90 0 1 200
Ex trud er [rp m]
Co
lour
Str
engt
h [%
]
H P, tumble, par tly filledH P, tumble, filled
H P, dispers ive, partly filledH P, dispers ive, filledM AX X, tumb le , par tly filled
M AX X, tumb le , filledM AX X, dispersive , part ly f illedM AX X, dispersive , filled
Heliogen Blue K 6902
8 0
8 5
9 0
9 5
10 0
10 5
11 0
11 5
12 0
12 5
13 0
13 5
14 0
0 3 00 600 90 0 1 200
Extrud er [rp m]
Co
lour
Str
engt
h [%
]
H P, tumble , par tly filledH P, tumble , filled
H P, dispers ive , part ly f illedH P, dispers ive , filledM A XX, tumb le, p ar tly filled
M A XX, tumb le, f illedM A XX, dispers ive, par tly filledM A XX, dispers ive, filled
• Colour strength a function of rpm• Different processing parameters: premix and extruder type, fill level• Pigments with big impact of processing parameters: up to 35% difference in colour strength• Pigments with low impact: < 10% difference in colour strength
Source: Dr. Ch. Guckel, BASF Schweiz AG; Leistritz Compounding Workshop 2011, Nuremberg
refreshing extrusion technology
31 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
31
Robust, easy dispersible, low influence of machine parameters Dispersibility: excellent
Calendering Effect: medium
Compaction tendency: no
Colour strength in narrowrange: < 10%
Dispersion energy through mixing and increase in rpmdeliver the optimum
ZSE MAXX better develops advantage of dispersive mixing
Cromophtal Red BNFP
95
100
105
110
115
0 300 600 900 1200
Extruder [rpm]
Col
our S
tren
gth
[%]
HP, tumble, partly filledHP, tumble, filledHP, dispersive, partly filledHP, dispersive, filledMAXX, tumble, partly filledMAXX, tumble, filledMAXX, dispersive, partly filledMAXX, dispersive, filled
Source: Dr. Ch. Guckel, BASF Schweiz AG; Leistritz Compounding Workshop 2011, Nuremberg
refreshing extrusion technology
32 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
32
Simple processing,with a “Plus” from pre-mixing Dispersibility: ok
Calendering Effect: no
Compaction tendency: no
Colour strength in mediumrange: D ~ 15%
Dispersive mixingshows an advantage
Lower rpm gives longerresidence time (more important than shear:Dispersibility versus Calendering)
Cromophtal Violet GT
85
90
95
100
105
110
0 300 600 900 1200Extruder [rpm]
Col
our S
tren
gth
[%]
HP, tumble, partly filledHP, tumble, filledHP, dispersive, partly filledHP, dispersive, filledMAXX, tumble, partly filledMAXX, tumble, filledMAXX, dispersive, partly filledMAXX, dispersive, filled
Source: Dr. Ch. Guckel, BASF Schweiz AG; Leistritz Compounding Workshop 2011, Nuremberg
refreshing extrusion technology
33 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
33
Straight forward – high throughput with big machine volume Dispersibility: excellent
Calendering Effect: no
Compaction tendency: no Colour strength in medium
range: D ~ 15%
Best results withintensive pre-mixing
Machinery advantage: with ZSE MAXX at high rpm / highthroughput, absence of dispersivepre-mixing gets compensated
Paliotol Yellow K 2270
90
95
100
105
110
115
0 300 600 900 1200Extruder [rpm]
Col
our S
tren
gth
[%]
HP, tumble, partly filledHP, tumble, filledHP, dispersive, partly filledHP, dispersive, filledMAXX, tumble, partly filledMAXX, tumble, filledMAXX, dispersive, partly filledMAXX, dispersive, filled
Source: Dr. Ch. Guckel, BASF Schweiz AG; Leistritz Compounding Workshop 2011, Nuremberg
refreshing extrusion technology
34 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
34
Dispersion properties with highest impact of machinery setup Dispersibility: excellent
Calendering Effect: strong
Compaction tendency: no
Pigment develops full colourstrength at short residencetime
Optimum with bigger volume(MAXX) and higher rpm
With no compaction tendency, the excellent dispersibility and potential for colour development is observed during pre-mixing and extrusion process
Paliogen Red Violet K 5011
95
100
105
110
115
120
125
130
135
140
145
0 300 600 900 1200Extruder [rpm]
Col
our S
tren
gth
[%]
HP, tumble, partly filledHP, tumble, filledHP, dispersive, partly filledHP, dispersive, filledMAXX, tumble, partly filledMAXX, tumble, filledMAXX, dispersive, partly filledMAXX, dispersive, filled
Source: Dr. Ch. Guckel, BASF Schweiz AG; Leistritz Compounding Workshop 2011, Nuremberg
refreshing extrusion technology
36 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
36
Summary
The dispersion characteristics of a pigment can be transferred well to the operating conditions of the dispersion process on a twin screw extruder
Results from the dispersion process can be explained with the characteristics of the dispersed pigment
The results help to optimize existing processes and production plants
In many cases, optimum results could be achieved using the bigger free volume of the ZSE 18 MAXX, especially with high throughput
Dispersive pre-mixing showed good results, especially with pigments offering excellent dispersibility and showing no compaction tendency
refreshing extrusion technology
37 - © Leistritz Extrusionstechnik GmbH - 15.02.2013
... any questions???Michael Thummert
Head of MarketingLeistritz Extrusionstechnik GmbH
Markgrafenstr. 29-39D - 90459 Nürnberg
Phone: +49 911 4306 [email protected]
... see films @ www.xxtrusion.tv