7. buss ag.pdf

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

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

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

Commercial availability of Carbon Black

Available as

Powder (fluff)

Pellets

Primary particle

LOWSTRUCTURE

HIGHSTRUCTURE

Aggregates

CB BASICS

ESD Primary performance criteria

• Conductivity

• Carbon black dispersion

• Surface smoothness

• Stiffness

• Impact strength

Conductivity

M ixing tim e

O ptim umm ixing tim e

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

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

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

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

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

Steps in the compounding of carbon blacks

Feeding

Wetting

Dispersive mixing (break up of pellets to

particles/aggregates)

Distributive mixing

CB COMPOUNDING

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

Shear mechanism in the Buss Kneader®

product flow

+ -

rotation

stroke

splitting

shearing

relaxation

reorientation

relaxation

reorientation

BUSS KNEADER

Buss Kneader® mixing mechanism

BUSS KNEADER

Differential features of Buss Kneader®

compounding technology

• Controlled and uniform shear mixing

• Precise temperature control

• Very high filler loading capability

BUSS KNEADER

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

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

CB Concentrates compounding – MX

Formulation 1: PE + 40% carbon black

Formulation 2: PE + 40% carbon black and mineral filler

PROCESS RESULTS

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

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

Quality Characteristics for

„Plastics Pipe Systems for Water Supply – Polyethylene (PE)“

QUALITY ISSUES

Filter Pressure Value Test

QUALITY ISSUES

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

Film Test

QUALITY ISSUES

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

•B

US

S C

OM

PO

UN

DIN

G P

LA

NT

CB Concentrate Plant with gravimetric feeding system

TYPICAL LAYOUT MX

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

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

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

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 homogeneity 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

7. buss ag.pdf

Documents

screen changer optional

ru major producer

typical layout mx

carbon black structure

screw speed

low structure

cb basics

process results