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New Long Rayon Fiber Reinforced ThermoplasticsUtilizing the LFT-D Process
ACCE, 12.-14. September 2005, Troy, USA
Dr. Frank HenningOliver Geiger
LFT – ein Werkstoff mit Zukunft Folie 2
Motivation for a LFT direct process
Semi-finished product
manufacturer
Semi-finished product
manufacturing GMT orLFT-G
Semi-finishedproduct
processing
Glassfibers
Additives
Polymerresin
+
MolderLFT
composite part
LFT direct process
LFT direct process
In-House Recycling
Economical advantageFlexible material composition
LFT – ein Werkstoff mit Zukunft Folie 3
Longfiber Reinforced Thermoplastics – New Material Development
Requirements:Mechanical propertiesMaterial homogeneityReproducibilityMaterial data forpart designReduction of localmaterial anisotropy
Definition long fibers:Injection molding:>1 bis 5 mmCompression molding:10 bis 40 mm Toughness
Stre
ngth
/ S
tiffn
ess
Rubber
Short fiber reinforced
plasticsLong fiberreinforced
plasticsParticle filled
plastics
Non reinforcedplastics
Toughness
Stre
ngth
/ S
tiffn
ess
Toughness
Stre
ngth
/ S
tiffn
ess
Rubber
Short fiber reinforced
plasticsLong fiberreinforced
plasticsParticle filled
plastics
Non reinforcedplastics
2002-09-12 - Page 4
In-line compounder
LFT die
Conveyor belt forLFT strand
HydraulicPress
Provision of rovings
Mixing extruder
Fully automized material handling
AVK-TV Innovationspreis
2001
LFT-D-ILC Base Equipment
LFT – ein Werkstoff mit Zukunft Folie 5
Materialproperties
Fiber diameter
Fiber length
Void contentProperties of polymer
Fiber-matrixdispersion
Fiber-matrixadhesion
Fiber orientation
Fiber content Fiber properties
Material development tailored to the application
LFT – ein Werkstoff mit Zukunft Folie 6
Adjustment of material properties based on requirements
Possibility of selection of polymer and fiber type
Company specific Know-How – Optimized for customer or applications
Material combination just looks complex – well managable
Individual intensity of backward integration possible (masterbatch)
Superset line control ensures safe and reproducible production
Material Development Flexibility
LFT – ein Werkstoff mit Zukunft Folie 7
Compression molding
LFT strand
Mixing extruder (Twinscrew compounder)
IL-Compounder
Presse
Polymers:- Polypropylen- Nylon: PA 6, PA 6.6 etc.- Polyethylenterephtalat (PET)- Styrenic Copolymers: ABS, ASA, SAN etc.- Blends
Reinforcements:- Glass fibers- Natural fibers- Carbon fibers- Synthetic fibers- cellulotic fibers
Flexibility for company specific solutions
LFT – ein Werkstoff mit Zukunft Folie 8
Flexibility in selection of matrix resins
60
78
112126
0
20
40
60
80
100
120
140
PP/GF30 ABS/GF30 PA/GF30 PET/GF30
Advanced LFT based on Engineering ThermoplasticsTe
nsile
str
engt
h [M
Pa]
Long fiber reinforced Engineering Plastics offer new applications for LFT´s
LFT – ein Werkstoff mit Zukunft Folie 9
Nor
m. P
rope
rties
[ -]
Fiber length l [mm]
1.0
0.8
0.6
0.4
0.2
0.10
100101
95 % level
Source:Schemme, SKZ-Fachtagung „Karosseriekonzepte mit Kunststoffen, Würzburg 2002 Based onThomason & Vlug
Stiffness: Fiber length 0,1 to 1mm Fillers and short fibers
Strength: Fiber length 1 to 10mm Short fibers
Impact: Fiber length > 10mm Long fibers
Strength
Impact
Stiffness
Nor
m. P
rope
rties
[ -]
Fiber length l [mm]
1.0
0.8
0.6
0.4
0.2
0.10
100101
95 % level
Nor
m. P
rope
rties
[ -]
Fiber length l [mm]
1.0
0.8
0.6
0.4
0.2
0.10
100101
95 % level
Source:Schemme, SKZ-Fachtagung „Karosseriekonzepte mit Kunststoffen, Würzburg 2002 Based onThomason & Vlug
Stiffness: Fiber length 0,1 to 1mm Fillers and short fibers
Strength: Fiber length 1 to 10mm Short fibers
Impact: Fiber length > 10mm Long fibers
StrengthStrength
ImpactImpact
StiffnessStiffness
Distribution of Fiber Length – Influence on Material Properties
LFT – ein Werkstoff mit Zukunft Folie 10
Mechanical properties DAM @ 23°C
9800
8437
10081
187
142
179
3 2.6 2.10
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
ZYTEL 70G30HSL BK39B, moulded ZYTEL 70G30HSL BK39B, machined N66 LFT 30%, machined0
20
40
60
80
100
120
140
160
180
200
E-modulusStress @ breakStrain @ break
+20%- 20%
Compression Molding(LFT-D)
Injection Molding
CAMPUSDatabase
Tensile Properties of Nylon PA6.6/GF30 @ 23°C
LFT – ein Werkstoff mit Zukunft Folie 11
• LFT brings a clear benefit in notched impact• Notched Charpy performance is trippled
KJ/m²
Notched Charpy @23°C
0
10
20
30
40
50
60
70
80
90
30% by weight glass
Injection molding
LFT-D Compression molding
50% by weight glass
Injection Molding
Compression Molding(LFT-D)
Notched Charpy Properties of Nylon PA6.6 and GF50 @ 23°C
LFT – ein Werkstoff mit Zukunft Folie 12
• LFT brings a clear benefit in multi-axial impact
2mm specimen thickness
Ene
rgy
(J)
Multiaxial Impact @ 23°C
0
500
1000
1500
2000
2500
3000
3500
70G30reference
Resin 1 Resin 2
Forc
e (N
)
0
2
4
6
8
10
12
14
16
Max. Force (N)Energy (Fmax) (J)Energy (J)
PA6 LFT 30% PA6 LFT 40%
InjectionMolding
CompressionMolding(LFT-D)
Multi-axial Impact of Nylon PA6.6/GF30 and GF40 @ 23°C
LFT – ein Werkstoff mit Zukunft Folie 13
Zytel®70G30
PP LFT 30%
Zytel®LFT 30%
Zytel®LFT 50%
Zytel®HTN LFT 50%
Zytel®75LG50HSL BK031
264°C255°C163°C0°C
Zytel®70G50 258°C
259°C
105 - 150°C
180 - 220°C
200 - 250°C
Engineering Polymers
Heat Deflection Temperature @ 1.81 MPA ISO 75-A
LFT – ein Werkstoff mit Zukunft Folie 14
PA66 LFT 50%
PA66 LFT 30%
70G35HSLX
PA66 LFT 50%
PA66 LFT 30%
70G35HSLX
• The LFT in-flow tensile modulus is 20% higher compared to 70G35• After 1000 hours, the LFT in-flow tensile modulus is 50% higher • LFT 50% brings another performance increase
Creep Measurements @ 130°C, 4000 MPa
LFT – ein Werkstoff mit Zukunft Folie 15
Goal: Modification of LFT-D-ILC process technology developed for the in-linecompounding of glass fibers for the direct incorporation of cellulose regeneratedfibers
Plastifikate
Twin-Screw Mixing Unit
IL-Compounder
Polymer Additives
Compression Molding
FiberRovings
LFT-D Material Development– Cellulose Fiber Reinforced PP
LFT – ein Werkstoff mit Zukunft Folie 16
Reduced density compared to glass fibers weight reduction: rCRF= 1,5 kg/dm³ versus rGF=2,5 kg/dm³
High elongation at break results in high impact resistance especially at low temperatures (T = -30°C)
Low sensitivity regarding splintering - qualification of RAYON fiber reinforced composites for automotive interior applications
Combination with biopolymers enable the in-line compounding of 100% renewable LFT
Reproducible material properties and continuous rovings compared to natural grown fibers
Advantages of engineering regenerated cellulotic fibers
LFT – ein Werkstoff mit Zukunft Folie 17
Cellulose is the most commonly existing natural product with an annual growth rate of approx. 1010 t
Cellulose = Poly (β-(1,4)-Anhydroglucose) Basic module: AGU = C6H10O5 (chem.),
Cellobiose (phys.)
Physical structure• semi-cristalline (Polymorphy)• fibrillar morphology (streched polymer chain)• physical structure still in discussion
Major problem: structural diversity – distinctive structural imperfection
Problems of industrial processing• Cellulose is not fusible• Cellulose is not soluble in common solvants• Cellulose first has to be isolated (chemical pulp manufacture from wood)
Chemical Structure: clarified by Haworth 1928
Cellulose
Quelle: Fraunhofer IAP
LFT – ein Werkstoff mit Zukunft Folie 18
Properties of hemp yarns of different origin
Material Source Yarn count Strenght Elongation Modulus
Provider tex cN/tex % cN/tex
Hanf 2.4/1 Rohemp 357.8 12.2 3.88 593
Hanf 5/1 Rohemp 205.3 12.9 3.80 518
Hanf 10/1 Rohemp 99.5 29.8 3.15 1148
Hanf 10/1 bleached Rohemp 75.8 17.7 1.95 1154
Hanf 10/1 Hattorf 93.6 17.3 2.77 767
Hanf 5/1 Polen 228.4 26.4 3.18 1349
Hanf 7.1/1 Polen 256.9 22.9 2.50 1434
Hanf 10/1 Polen 103.4 23.4 2.66 1253
Engineering Cellulose Stable Fiber Cordenka 244 51,7 12.5
Quelle: Fraunhofer IAP
LFT – ein Werkstoff mit Zukunft Folie 19
Cellulose Fibers
Quelle: Fraunhofer IAP
Natural Fibers
Bast Fibers
Seed Fibers
Cellulose Fibers
Leaf Fibers
Cotton woolKapok
FlaxHemp
Agave (Sisal and others)Banana (Manila-Hemp and others)Lilienfaser (New Zealand-Hemp)Coco Fibers (Fruit Fibers)Grass Fibers
JuteRamie
Wood Fibers
HardwoodSoftwood
Viscose Carbamat
Lyocell
Cupro
Enginnering Stable Fibers= cellulosic synthetic fibers= man-made cellulosics= cellulose-stable fibers
Engineering Stable Fibers
LFT – ein Werkstoff mit Zukunft Folie 20
CRF in Composites - Processing
Manufacturing of semi-finished products
Injection Molding, Extrusion of PP/CRF-Granulates
Manufacturing of semi-finished products
Injection Molding, Extrusion of PP/CRF-Granulates
Incorporation of continuous fibersIn thermoplastic melt
Incorporation of chopped CRF-Fibers
Incorporation of continuous fibersIn thermoplastic melt
Incorporation of chopped CRF-Fibers
InjectionInjection
CompressionCompression
AutomotiveInterior
AutomotiveInterior
AutomotiveInterior
AutomotiveInterior
InjectionInjection
CompressionCompression AutomotiveInterior
AutomotiveInterior
ElectronicsHousings
ElectronicsHousings
LFT – ein Werkstoff mit Zukunft Folie 21
Processing of Granulates by Compression Molding
Granulate PPRayCo25 Basic
BeamStructure
Einschneckenextruder
Compression Molding
Plastifikate
Presse
Melting of granulates insingle-screw extruder
LFT – ein Werkstoff mit Zukunft Folie 22
Polypropylene with 25 percent by weight RAYON short fiber reinforcement
Properties Procedure Unit Norm measured value
Matrix resin PPFiber content wt.% 25
Tensile modulus 2mm/min GPa ISO527 2,7
Tensile strength 50mm/min MPa ISO527 72Strain at break (tensile) 50mm/min % ISO527 12
Flexural modulus 2mm/min GPa ISO178 2,1
Flexural strength 2mm/min MPa ISO178 60
Flexural tension at 3,5% 2mm/min MPa ISO178 52
Charpy Impact (un-notched) 23°C, 4J kJ/m2 ISO179 85-18°C, 4J kJ/m2 ISO180 83
Charpy Impact (notched) 23°C, 4J kJ/m2 ISO179 11
-18°C, 4J kJ/m2 ISO180 7
Hardness Shore D 23°C DIN53505 70
Heat deflection HDT-A 1,8 MPa °C ISO75 80
Density calculated g/cm3 0,998
Source: http://w
ww
2.iap.fhg.de/verbundwerkstoffe/de/index.htm
l
Material Properties of Injection Molded Parts (Short Fiber Reinforced)
LFT – ein Werkstoff mit Zukunft Folie 23
Direct Processing of CRF Composites - Challenges
Chopping of CRF – high elongation
Homogenisation of chopped fibers in matrix polymer by mixing unit
Cutting of CRF-LFT plastificates into strands for compression molding
Compatibility of fibers and polymer – fiber-matrix adhesion
Optimization of flow capability of CRF reinforced polymer
LFT – ein Werkstoff mit Zukunft Folie 24
Direct Processing of CRF Composites – Process Modifications
Pressing RollerCRF-Rovings
Compounding-Extruder
Mixing Unit
Polymer-Melt Film
Infeed Zone
Chopped CRF Fibers
Feeding Chute
Cutting Roller
Polymer
LFT – ein Werkstoff mit Zukunft Folie 25
Significant improvement of material homogeneity by process optimization
Optimized LFT-D Technology(25 Gew.-% fiber content)
LFT-D Technology – not optimized(25 weight-% fiber content)
Direct Processing of CRF Composites – Material Homogeneity
LFT – ein Werkstoff mit Zukunft Folie 26
Polypropylene with 20 percent by weight RAYON long fiber reinforcement (fiber length 12 mm) compared to long glass fiber reinforced PP
Material Properties of Extrusion Compression Molded Parts
Zug-E-Modul
0
1000
2000
3000
4000
5000
Faserorientierung 0° Faserorientierung 90°
[MPa]
LFT-D PP/GF30LFT-D PP/CRF20
Stiffness – E-Modulus
Fiber orientation 0° Fiber orientation 90°
Zugfestigkeit
0102030405060708090
Faserorientierung 0° Faserorientierung 90°
[MPa]
LFT-D PP/GF30LFT-D PP/CRF20
Tensile Strength
Fiber orientation 0° Fiber orientation 90°
LFT – ein Werkstoff mit Zukunft Folie 27
Polypropylene with 20 percent by weight RAYON long fiber reinforcement (fiber length 12 mm) compared to long glass fiber reinforced PP
Material Properties of Extrusion Compression Molded Parts
Durchstoßenergie
0
2
4
6
8
10
12
14
16
18
[J]
LFT-D PP/GF30LFT-D PP/CRF20
Falling dart test
Charpy Impact un-notched
01020304050607080
Fiber orientation 0° Fiber orientation 90°
[kJ/m²]
LFT-D PP/GF30LFT-D PP/CRF20
LFT – ein Werkstoff mit Zukunft Folie 28
Current Material and Process Developments
Development of a process unit for large scale production equipment in cooperation with Dieffenbacher
Suitable cutting technology for this type of synthetic fibersAutomated handling of LFT-Strands
Optimization of material compositionMixing of Glass and CRF for improvement of HDT ValueStabilization/Additives for flame resistance with respect to railwaytransportation
Use of biopolymersComposites made from 100% renewable RessourcesPolylactid (Polylactic acid PLA) in combination with CRF
LFT – ein Werkstoff mit Zukunft Folie 29
CRF in Biopolymers – Tensile Strength
124
61
7870
0
20
40
60
80
100
120
140
PP/GF30 PLA/GF30 PP/CRF25 PLA/CRF25
Zugf
estig
keit
[MP
a]
LFT – ein Werkstoff mit Zukunft Folie 30
10200
2900
52006500
0
2000
4000
6000
8000
10000
12000
PP/GF30 PLA/GF30 PP/CRF25 PLA/CRF25
Zugm
odul
[MPa
]
CRF in Biopolymers – Tensile Strength
LFT – ein Werkstoff mit Zukunft Folie 31
LFT-D Regenerated Cellulotic Fiber Reinforced Polypropylene
Unterbody Cover OPEL Corsa made of
PP/CRF20, 20 weight-% Fibers
VOLVOUnderbody Cover Made of PP/CRF25, 25 weight-% Fibers
LFT – ein Werkstoff mit Zukunft Folie 32
Characterisation of combustion behaviour of different composites
25 weight-% CRF reinforcedPolypropylen (IAP granules, short fibers), injection molded
25 weight-% CRF reinforcedPolypropylen (ICT, LFT-D), compression molded
30% glass fiber reinforcedPolypropylen (ICT, LFT-D),compression molded
Length of burning timefor 100mm
229 s
Length of burning timefor 100mm
327 s
Length of burning timefor 100mm
233 s
Flame Retarding Behaviour of CRF Composites
LFT – ein Werkstoff mit Zukunft Folie 33
Summary
Extended and modified LFT-D-ILC technology employing chopped fiberdosing technology leads to an economic manufacturing of CRF reinforcedparts
Compression molding is an attractive process technology especially whenmanufacturing large parts and a high number of units
High mechanical properties enable the use of the compound for automotiveapplications
Long fibers provide high impact strength and avoid slivering of the part duringdamage
Regarding material homogeneity the process technology was optimized
Successful manufacturing of demonstrator parts
LFT – ein Werkstoff mit Zukunft Folie 34
http://www.neue-verbundwerkstoffe.de
http://www.ict.fraunhofer.de