Hybrid yarn development for thermoplastic composites in visible automotive applications Objective & Approach
The European Union has set a specific goal regarding CO2 emissions: Compared to 2009, CO2 emissions are to be reduced by 20 % until 2020. For the automotive industry, the most promising area of research is lightweight construction. FRTCs, so-called organic sheets, have the potential for large scale series production. On the other hand high production cycle times and a poor surface quality are limiting their potential. Therefore, ITA’s current research approaches these problems in two ways. Nanomodified materials and a new tool concept for heat pressing are going hand in hand and may lead to the technology’s breakthrough. Both are part of the public funded project “VarioOrgano”. The goal is to analyse the potential of these modified yarns and the tool system during the FRTC production. Particle / PA 6
Nano compound
Modified PA 6 yarn
Hybrid yarn
Biaxialgestrick
Material Level
Organic sheet
0°
90° +45° 45°
Binderverfestigte Gelege
Biaxiale Gewirke
Multiaxiale Gewirke
Biaxialgestrick Biaxiale Gestricke
Multiaxialgestrick Multiaxiale Gestricke
3D-Abstandsgewirk mit Dickensprung 3D-Geflechte
Drehergewebe
3D-Abstandsgewirk
0° 90°
Abstandsgewirke
+45°
Abstandsgewebe
45°
Process Level
Hybrid yarn
Delivery godet
Tested Materials
Multiaxialgestrick
2D-fabrics Biaxiale Gelege
• Melt spinning of nanomodified nylon 6 filament yarns • Development of hybrid yarns based on glass fibres and nylon 6 filament yarns • Evaluation of the hybrid yarns regarding fibre strength, mixing homogeneity and processability • Definition of a suitable parameter set for large scale production of hybrid yarns
0° 90° +45° 45°
• Polyamide 6: Ultramid® B24 N 03 from BASF SE • Boron Nitride: 3M™ Boron Nitride Powder Grade S1-SF from ESK Ceramics GmbH • Polyamide 6 filament yarn: spun with a take-up velocity of 800 m/min without additional drawing. Yarns with up to 10 wt% of Boron nitride particles were successfully spun without fiber breakage in time intervals of 30 minutes. • Glass fibres with 600 tex (TUFROV 4510 from PPG Industries) Glass fibre
Used machines Compounding
Filament spinning
Air jet mixing
Textile production
Heat pressing
Testing
Parameters for hybrid yarn production
• Melt spinning machine from Fourné Polymertechnik, Alfter, Germany • Air jet mixing machine for hybrid yarn production
Mixing nozzle Feeding godets
Pressure p [bar] Nylon 6 fibre Air jet mixing machine for hybrid yarn production
Nylon 6 filament yarn unmodified (left) and modified with Boron Nitride (right)
Analysis and testing
Tensile strength σ [N/tex]
0,35
5 cm Hybrid yarn based on Boron Nitride modified nylon 6 filament yarns and glass fibres
• The hybrid yarns A02, A05, A09, B02, B05, B10, C02, C05, C10, D02, D05 and D10 as the most promising are selected for testing. • The mixing behaviour is determined using microscopy analysis. The microscopy pictures are assessed qualitatively according to the parameters opening and mixing (+ = good, o = neutral, - = poor)
0,25 0,2 0,15 0,1
0,05 A02 A05 A09 B02 B05 B10 C02 C05 C10 D02 D05 D10 GF1 Sample n [-]
Tensile strength of hybrid yarns
Discussion
sample: A02 A05 A09 B02 B05 B10 C02 C05 C10 D02 D05 D10 opening + O O O + O + + + mixing O O O + O + O + • For assessing the processability the assumption that loops will cause problems in a following weaving process is made. For each sample average maximum loop size within one meter of the hybrid yarn is analysed (sample A02: Fibres are parallel without any loops).
K. Vonberg1, R. Brüll1, B. Mohr1, T. Gries1 1RWTH Aachen University, Institut für Textiltechnik, Germany 1E-mail:
[email protected]
0,3
0
Loop size of hybrid yarns for determination of their processability
The development of hybrid yarns based on glass fibres and Boron Nitride modified filament yarns was successful. A homogenous distribution of the glass and thermoplastic fibres is important for the heating properties and a homogenous consolidation. The determined tensile strength is similar to each other. Thus, the focus is on mixing quality and processability of the hybrid yarns. The assessment and correlation of the analysed results is necessary in order to choose one sample for further processing. The sample C05 (marked in red) reaches the highest score. The processing parameters of sample C05 will be chosen for further manufacturing of fabrics and FRTCs in the near future.
Acknowledgement This research was funded by the Bundesministerium für Wirtschaft und Energie. We thank our corporate partner Sigel GmbH, Kirchheim unter Teck, Germany who provided insight and expertise that greatly assisted the research.
3,0
3,5
4,0
4,5
5,0
60 01
02
03
04
05
75 06
07
08
09
10
90 11
12
13
14
15
Conclusions & Outlook
Results
10 cm
• Air jet mixing machine for hybrid yarn production is used: both fibres are mixed and fixed by compressed air. • Process parameters are: nozzle pressure p, production speed v, overfeeding φ. • P24 nozzle with overfeed φ: GF 1 % and PA 3 % (Test A) and GF 1 % and PA 4 % (Test B). • BCFW nozzle with overfeed φ: GF 1 % and PA 3 % (Test C) and GF 1 % and PA 4 % (Test D). • Tests A – D are performed for the following parameter set.
Speed v [m/min]
Introduction & Motivation
Experimental Setup
The cycle time reduction is important for mass production of thermoplastic composites. In doing so, the production costs can be reduced and the efficiency can be enhanced. Vario thermal technologies are suitable for the heating of nanomodified thermoplastic matrix material to produce thermoplastic composites. In the frame of this research nanomodified filament yarns are produced and processed to hybrid yarns and fabrics. The hybrid yarns are evaluated regarding fibre strength, mixing homogeneity and processability. The focus is on mixing homogeneity and processability as the fibre strength is similar to each other. The result is a suitable parameter set (C05) for hybrid yarn production. These yarns will later be processed to non crimp fabrics. The consolidation is realised by the developed vario thermal heating system.
Institut für Textiltechnik (ITA) der RWTH Aachen University Otto-Blumenthal-Straße 1, 52074 Aachen, GERMANY www.ita.rwth-aachen.de Tel: +49 241 80-23400 Fax: +49 241 80-22422
