More from the EDANA NIA 2013 Conference in Roubaix...
Philippe Mesnage of ITFH (France) is evaluating hydroentanglement as an alternative to needlepunching for making flax nonwovens for composite reinforcement. The raw flax contains ~70-75% cellulose with 10-15% of hemicellulose, 3-5% lignin and a similar proportion of pectins. Mechanically refined flax (MRF) tows were cut into lengths of 25-35mm for airlaying and compared with a more fully refined 45mm flax intended for spinning into yarns (SF). MRF was coarse – 34 to 90 on the IFS scale (Flax Standard Index) compared with 20-30 IFS for the SF fibres. These long fibres clogged the air-lay drums and further work was carried out with fibres chopped to 15mm which could be successfully laid into ~150gms sheets.
After hydroentanglement, nonwoven tensile strengths were
highest for the SF fibres (358N/5cm) compared with 215N/5cm for the best of the
MRF. Tear strengths were however
comparable, presumably due to the higher denier of the MRF. The extra stiffness of the MRF samples was
not just down to the coarser fibres. Mr
Mesnage thought the non-cellulose components of the fibre were being solubilised
in hydroentanglement and acting as a chemical binder. Asked what advantages this route might have
over the needlepunched route he thought there was a potential for higher
productivity from the faster laying and bonding machinery and added that the
end product was completely natural, made in the EU and used no added binders.
No comments:
Post a Comment