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New Developments in Compounding Biomaterials
Prof. Daniel SchwendemannDep. Head of IWKInstitute of Material Sciences and Plastics ProcessingUniversity of Applied Sciences Eastern Switzerland, Rapperswil
Content
IWK - Institute of Material Science and Plastics Processing
Overview of the Compounding systems
Process needs, machine requirements
New developments in Compounding
Feed Enhanced Technology
Feeding of Liquids
Injection Nozzles
Side Degassing
Project presentation “FluidSolids”
New Developments in Compounding Biomaterials2
Welcome to the Hochschule für Technik, RapperswilPart of the University of Applied Science Eastern Switzerland
New Developments in Compounding Biomaterials3
Biomaterials / Biopolymers
Biomaterials:
Biopolymers as PLA, PHA (PHB), Starch, etc.
Biofibers/Biomass as Cellulose, Hemp, Flax, Woodfibers etc.
Material performance (concerning processing):
Shear sensitive -> low shear
Temperature degradable -> low temperature
Moisture sensible -> good degassing behavior
Processed in water -> high moisture content
New Developments in Compounding Biomaterials4
Typical steps in plastics processing
New Developments in Compounding Biomaterials5
RawMaterial
Material Handling
Compounding
InjectionMolding Testing
Compounding systems
New Developments in Compounding Biomaterials6
+
Single screwextruders Twin screw extruders
Co-rotating counter-rotating
intermeshing
+ + + + + +
notintermeshing
Multiple screwextrudersBuss-Kneader
+
Bulk material handling
Bulk materials are solid goods, the behavior could vary between solid goods and liquids
solid bulk liquid
New Developments in Compounding Biomaterials7
Bulk material handling
New Developments in Compounding Biomaterials8
Bridgebuilding or flow problems in the hopper
Feed section design
New Developments in Compounding Biomaterials9
Feed section: feed limitation
Wrong design
Bulk density0,25 g / dm³
Bulk density0,08 g / dm³
Extruder
FeederFilter bag
Filter bag
Specially fine powders arecatching a lot of additionalair in the feeding pipe.
feederFilter bag
Extruder
Filter bag
Correct design
Co-rotating Twin Screw Extruder / process section
New Developments in Compounding Biomaterials10
𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃 𝐿𝐿𝑃𝑃𝐿𝐿𝐿𝐿𝐿𝐿𝐿 =𝐿𝐿𝐷𝐷𝑎𝑎
Scale up – Influence of cooling and heating
Cooling or heating surface versus volume or throughput
New Developments in Compounding Biomaterials11
Screw diameter in mm
Do
Dia
0.00
10.00
20.00
30.00
40.00
50.00
60.00
0
5
10
15
20
25
30
25 40 50 58 70 92
Area in sqm/40 D
Volume in l/40 D
Ratio l/sqm
Scale up factorbased on ZSK 25
𝐷𝐷𝐷𝐷𝑎𝑎𝐷𝐷𝑃𝑃𝐿𝐿𝑃𝑃𝑃𝑃 𝑅𝑅𝑎𝑎𝐿𝐿𝐷𝐷𝑃𝑃 =𝐷𝐷𝑎𝑎
𝐷𝐷𝐷𝐷
Feed Enhancement Technology
FET: Technology to increase the throughput of feed limited products
Solids conveying is improved byapplying vacuum in the feed zone toa wall section which is porous andpermeable to gas
New Developments in Compounding Biomaterials12
This wall section is realized by an insert with a filter membrane installed in an open barrel.
FET Installation possibilities
New Developments in Compounding Biomaterials13
ZSKZS
B
In the side feeder(ZS-B)
In the feed section of the ZSK
downstream of feeding point
In the feed sectionof the ZSK
upstream of the feeding point
FET can only be used for solids conveying!
FET Mechanism
New Developments in Compounding Biomaterials14
vacuum Filter cake:compacted powder
FET insert
Effects:• air is removed higher bulk density• friction is changed in the area of insert
air
FET Mechanism
New Developments in Compounding Biomaterials15
Friction and higher bulk densityincrease the conveying angle:
Conveying angle capacity
FET nicht aktiv
Angle of conveying approx. 20°
FET aktiv
Angle of conveying approx. 40°
Q = F * H * n * ε * η * γ
low
high
FET Mechanism
New Developments in Compounding Biomaterials16
SEI can be reduced by:• increasing capacity at same screw speed• reducing screw speed at same capacity
Cap
acity
[kg/
h]
screw speed [min-1]
without FET
with FETSEI4 < SEI1
SEI4
SEI3
SEI2
SEI1
Biobased Materials processed with water
New Developments in Compounding Biomaterials17
BiobasedMaterials
processes in water
Drying step
(Milling)
Powder Dosing
Com-pounding
BiobasedMaterials
processes in water
Dosing Liquids
Com-pounding
with a high amoumt of
water
Drying step
(Milling)
Steps in material preparation for the compounding process
Challenges with water based fillers
New Developments in Compounding Biomaterials18
By adding Filler and water into the extruder, the water evaporates and cools the polymer down.
Energy input is needed, that the aggregate state of the polymer doesn’t change. Polymer should not “freeze”
(Energy input caused by conveying or mixing is not calculated.)
End productExtruder
Polymer
X%
Filler+ H2O
Water Vapor
HeatingCapacity
Compounding water based Fillers/Fibers
New Developments in Compounding Biomaterials19
A calculation toolInput
Final Product3.5% Fiber + H2O melted
PolymerFiber+H2O Fiber H2O Polymer Compound Unit
Quantity 100 3.5 96.5 5.00 NFC %Density ρ 1.2 kg/dm3Volumetric Flow V 3.76 l/h
Mass Flow m4.51 0.16 4.35 3.00 3.16 kg/h
0.00125 0.00004 0.00121 0.00083 0.00088 kg/sRoom Temperature T1 20 20 20 20 °COperating Temperature T2 200 200 100 200 °CMelting Point Ts 150-160 °CEnthalpie (20°C to 100°C) Δh 2591000 J/kg
Specific Heat Capacity cp 4092.78 1550 4185 1200 J/kgK
Heat Flows of: Result UnitHeating Capacity Hh 3549.94 WPolylactide Hp 180.00 WInput NFC+H2O Hin 0.00 WOutput Water Vapor Hw 3537.70 WEnd product Hpnfc 192.24 WTemperature Endproduct t 200.00 °C
Compounding water based Fillers/Fibers
New Developments in Compounding Biomaterials20
0
500
1000
1500
2000
2500
3000
3500
4000
0 5 10 15 20 25
Hea
t Cap
acity
[W]
Quantity Fibrous Material in Input [%]
Needed Heat Capacity for Fibrous-Suspension
end product 1% NFC, mp=3kg/h
end product 3% NFC, mp=3kg/h
end product 5% NFC, mp=3kg/h
Injection Nozzle Technology
Injection Nozzle
New Developments in Compounding Biomaterials21
the spring load must be adjusted according to the extruder pressure to prevent entering of melt
spring preload
pump pressure
extruderpressure
spring preload
extruderpressure ≤
for opening, the pump pressure must be bigger than the spring preload
spring preload ≤ pump
pressure
Injection Nozzle Technology
New Developments in Compounding Biomaterials22
liquid flow The lifting of the needle creates an annular gap.
Only a small axial movement of the needle is necessary to create the full crosssection area.
Injection Nozzle Technology
New Developments in Compounding Biomaterials23
0
50
100
150
200
250
300
350
400
450
500
0 10 20 30 40 50 60 70 80
Pressure [bar]
Thro
ughp
ut [k
g/h]
1/ 1 mm; Water
2/ 2mm; Water3/ 3mm;Water
4/ 1mm; Oil
5/ 2mm;Oil6/ 3 mm Oil
7/ 1,7mm;Oil
8/ 1,7mm;Oil+SpringsLoads
Characteristics for throughput
Problem Lab-Scale!!!
Degassing of the process section / Side Degassing Unit
New Developments in Compounding Biomaterials24
Picture Coperion
Venting Port
Project «FluidSolids»
Process optimization Compounding
Goals
Analysis of the current process Optimization of system configuration
(screw design, position of feeding, process parameters, …)
Operating tests
Partners
FluidSolids AG, Zürich
Funding
Public and Private
25New Developments in Compounding Biomaterials
New Developments in Compounding Biomaterials26
Project: FluidSolids® - Impressions
Project: FluidSolids®
New Developments in Compounding Biomaterials27
Project: «FluidSolids®»
New Developments in Compounding Biomaterials28
Umweltpreis der Schweiz 2016
Environmental Award of Switzerland 2016
Project «FluidSolids»
New Developments in Compounding Biomaterials29
Summer 2016New CompoundingPlant starts in Switzerland
Project «FluidSolids»
New Developments in Compounding Biomaterials30
Extrusion trials at the IWK Lab
Thank you very much for yourattention!
Prof. Daniel SchwendemannIWK Compounding/ExtrusionUniversity of Applied Sciences Eastern [email protected]+41 55 222 4916