Introduction
About 100 delegates, mainly staff and students from Europe’s
technical institutes and universities attended this now bi-annual conference. Two
thirds of the papers presented were from technical institutes and universities
and provided interesting updates on progress made on numerous EU-funded
initiatives in nonwovens.
PLA Meltblown
Ryan
McEneany, Research Scientist, Kimberly Clark, USA described the
outcome of a 10 year development programme on biopolymers. This was part of a strategy to cease being
the world’s largest single user of polypropylene and become a major user of
sustainable materials. Their PP use was
mainly in SMS processes and while PLA worked well in spunbond, it was difficult
in melt-blown due to the non-availability of the right Melt-Flow Rate.
Commencing with Natureworks 6201D PLA resin (MFR = 80g/10min
at 210oC), quite apart from the viscosity problem, they experienced
slow crystallization due to its high Tg (~60oC), high fibre
shrinkage, biased orientation in the web and poor thermal bonding when draw
ratios were high. They looked at flow
modifiers, higher process temperatures and lower molecular weight polymers and
it was the latter, obtained by processing undried resin, which showed the most
promise...
