AM
I's T
herm
opla
stic C
oncentr
ate
s 2013
Latest achievements in the compounding of high
performance carbon black concentrates
Hans M. Huegel, Buss AG, Pratteln, Switzerland
Alf Hofstetter, Buss Asia – Pacific, Singapore
Hans-Ulrich Siegenthaler, BUSS AG, Pratteln, Switzerland
Page 2
Contents
Carbon Blacks and their characteristics
Uses and applications of black concentrates
Quality requirements and control principles
Key features of the Buss Kneader® and actual results
Buss Kneader® plant concept and layout
Summary
CONTENTS
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The Fundamental Properties of Carbon Blacks
A carbon black is characterised by a
number of important properties
Microstructure (crystalline layers)
Surface area / Particle size
Structure (morphology of primary aggregate)
Surface chemistry
CB BASICS
Page 4
Commercial availability of Carbon Black
Available as
Powder (fluff)
Pellets
Primary particle
LOWSTRUCTURE
HIGHSTRUCTURE
Aggregates
CB BASICS
Page 5
ESD Primary performance criteria
• Conductivity
• Carbon black dispersion
• Surface smoothness
• Stiffness
• Impact strength
Conductivity
M ixing tim e
O ptim umm ixing tim e
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Properties related to Carbon Black particle size
Fine particles Property Large particles
Darker Masstone colour Lighter
Stronger Tint strength Weaker
Harder Dispersion Easier
Higher Conductivity Lower
Higher Viscosity Lower
Slower Wetting Faster
CB BASICS
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Properties related to Carbon Black structure
High Structure Property Low Structure
Easier Dispersability More difficult
Slower Wetting time Faster
Lower Gloss Higher
Lighter Masstone colour Darker
Lower Tint strength Higher
Higher Conductivity Lower
Higher Viscosity Lower
Lower Loading capacity Higher
CB BASICS
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Uses of carbon black
Carbon blacks are combined with polymers
in order to impart a variety of properties
Electrical conductivity
Colour and opacity
UV resistance
Thermal conductivity
Reinforcement
CB APPLICATIONS
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Applications for carbon black masterbatch
The production and subsequent let down of 40 to 50% black
masterbatch is commonly used in:
General purpose (colouring)
Engineering plastics (colour, jetness, UV, conductivity,
antistatic)
Speciality film, geomembranes (UV)
Pipes (UV, antistatic)
W&C compounds (UV)
Fibres (colour, tint, gloss)
CB APPLICATIONS
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Value added applications
Where the highest level of dispersion is needed for:
• End-user specifications / requirements
or
• Severe conditions imposed during the transformation step
• Examples
- Pipe
- Cable extrusion compounds
- Fibre production
- Electrostatic Discharge (ESD) application
CB APPLICATIONS
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Steps in the compounding of carbon blacks
Feeding
Wetting
Dispersive mixing (break up of pellets to
particles/aggregates)
Distributive mixing
CB COMPOUNDING
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Requirements of the compounding system
Highest degree of dispersion
No thermal degradation of temperature sensitive polymers
No damage to physical structure of carbon black
Consistent and reproducible product quality
Highest possible throughputs
CB COMPOUNDING
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Shear mechanism in the Buss Kneader®
product flow
+ -
rotation
stroke
splitting
shearing
relaxation
reorientation
relaxation
reorientation
BUSS KNEADER
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Buss Kneader® mixing mechanism
BUSS KNEADER
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Differential features of Buss Kneader®
compounding technology
• Controlled and uniform shear mixing
• Precise temperature control
• Very high filler loading capability
BUSS KNEADER
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Drilled pins for thermocouple placing
Direct immersion in polymer
Precise stock temperature
Temperature profile of process
Process control “ON-LINE”
Thermocouple
located in pin
and directly
immersed in
polymer
BUSS KNEADER
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Process Technology: Features
Optimised screw geometry:
Newly designed and patented process elements for balanced
conveying, mixing and energy dissipation.
Balanced Volume and Torque
MKS: 3 flight design Do/Di = 1.55
Do/stroke = 6.67
MX: 4 flight design Do/Di = 1.71
Do/stroke = 5.50
quantec® EV: 4 flight design Do/Di = 1.56
Do/stroke = 4.77
MX TECHNOLOGY
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CB Concentrates compounding – MX
Formulation 1: PE + 40% carbon black
Formulation 2: PE + 40% carbon black and mineral filler
PROCESS RESULTS
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Results of CB Concentrates compounding
Formulation 1 PE + 40% carbon black
Formulation 2 PE + 40% carbon black + inert filler
Data Output
(kg/h)
Screw speed
(rpm)
Spec energy
(kWh/kg)
TempT7
(°C)
T / 100 rpm
(°C)
Formulation 1 525 750 0.171 242 7.9
Formulation 2 800 750 0.114 208 3.5
PROCESS RESULTS
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Results Semicon-processing – MX vs MKS
PE Copolymer + 35 - 40% Conductive CB
Buss
Kneader
Type
Through-
put
(kg/h)
Screw
speed
(rpm)
Spec. Energy
(kWh/kg)
Saving
(%)
Temp
T7
(°C)
T7
(°C)
T (°C)
/ 100
rpm
MKS Pilot 180 450 0.250 0 212 --- 20.0
MX Pilot 500 750 0.172 31 209 -3 7.0
PROCESS RESULTS
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Quality Characteristics for
„Plastics Pipe Systems for Water Supply – Polyethylene (PE)“
QUALITY ISSUES
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Filter Pressure Value Test
QUALITY ISSUES
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Filter Pressure Value Test
QUALITY ISSUES
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Filter Pressure Value vs. Output Rate
FPV vs. Output Rate
0.80
0.90
1.00
1.10
1.20
1.30
1.40
1.50
1.60
1.70
150 160 170 180 190 200 210 220 230 240 250
G [kg/h]
FP
V [
ba
r*c
m^
2/g
]
70/30 60/40 Ref. Linear (Ref.) Linear (60/40) Linear (70/30)
Ref
Split-Feed 70/30
Split-Feed 60/40
Test Mixture:
MB 100g
Base Polymer 400g
Total 500g
(containing 40g C.B.) Trial 1.3
Trial 1.1
Trial 1.2
QUALITY ISSUES
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Film Test
QUALITY ISSUES
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Film Test
QUALITY ISSUES
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Film Test
QUALITY ISSUES
Page 28
water transport system for pellets
centrifugal dryer
water tank
fines removal sieve
under water pelletiser
melt pump
diverter valve
control cabinet
control PC
with rack
drive cabinet
oil heating / cooling units degassing unit
vertical inlet screw
kneader
pellet outlet
water heating / cooling units
water bypass system
TYPICAL LAYOUT MX
Typical Layout CB Concentrate Plant
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•B
US
S C
OM
PO
UN
DIN
G P
LA
NT
CB Concentrate Plant with gravimetric feeding system
TYPICAL LAYOUT MX
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Applications
CB Concentrates 15 or 22 L/D, Melt Pump
2 or 3 Inlet Screws, under water pelletiser
(screen changer optional)
Semiconductive 15 or 22 L/D, Melt Pump
CB Compounds 2 or 3 Inlet Screws, under water pelletiser
(screen changer optional)
Black jacketing 15 L/D, Melt Pump
Compounds 1 Inlet Screw, under water pelletiser
TYPICAL LAYOUT MX
CB Compound Type Buss Kneader line configuration
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MX Sizes and Output Rates (kg/h)
CB
Concentrate
Semi-conductive
CB Compound
Black Jacketing
Cable Compound
MX 30 5-25 5-25 5-25
MX 58 250-350 150-250 250-350
MX 85 650-950 500-750 650-950
MX 105 1200-1900 700-1300 1200-1900
MX 125 2400-3200 1500-2500 2400-3200
MX 140 3000-4500 2500-3500 3000-4500
TYPICAL LAYOUT MX
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Most recently installed MX Kneaders for CB compounding
in addition to the MX 58-15/22 in Buss lab:
Major Producer, BE MX 140-15 F 260-8 Semicon & CB Masterbatch
Major CB prod., CN MX 140-22 P 140 CB Masterbatch
Major Compdr., CN MX 105-15 F 200-6 Talcum Masterbatch
Major Producer, RU MX 125-15 P 140 CB Masterbatch
Major Producer, RU MX 125-15 F 250-6 CB Masterbatch
Major Producer, TH MX 105-15 P 110 Semicon & CB Masterbatch
Totally world wide sales CB MB: approx. 30-40 machines (incl. older types)
References
TYPICAL LAYOUT MX
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Summary - Carbon Black Compounding
Successful compounding of carbon black masterbatch requires
• Highest output rates while maintaining an on-going level of
quality and consistency
• Optimum dispersion and product hom*ogeneity as the key for:
– End-user properties
– Extrusion properties
– Processing parameters
• Controlled shear mixing without damage to polymer and
carbon black structure
• The Buss Kneader® provides the optimum in product
dispersion leading to improved product and end-user
performance
SUMMARY