The main route to future growth for spunmelt nonwovens is likely to be in the development of ever more textile-likematerials to replace woven fabrics.
This was the view expressed by Arnold Wilkie, president of US extrusion specialist Hills Inc., at the recent Edana Nonwovens Symposium in Baveno, Italy.
It is a view widely held by industry analysts. All of the technology is already in place, and the mass-market economics certainly make sense. It now just appears to need somebody, somewhere – probably in Asia – to make a visonary leap and take the risk of investing considerably in a sophisticated spunmelt nonwovens plant to replace what an entire armoury of weaving machines can do.
The aim should be convincing the end-buyer – the retailer – that the established channels have existed for too long, and can be changed quickly and fairly easily.
The ability to add a sustainability element – through, say, the replacement of polypropylene with PLA, in addition to considerable energy and raw materials savings – could prove an irresistable sell-on to consumers.
What are the retail visionaries waiting for?
In reviewing the progress of spunbond and meltblown nonwovens technology, Mr Wilkie put the worldwide production of these materials at around 2.5 million annual tonnes in 2009 – 80% of which is polypropylene.
Growth rates up to 2009 were 10% per annum and China alone produced 1.1 million tonnes of spunmelts, 90% being polypropylene, in 2009,with growth of 25% year.
Only an annual 500,000 tons of polyester spunmelt is required globally, meaning just three or four continuous polymerisation units could supply the entire spunmelt PET industry.
Of the other polymer systems currently available, Mr Wilkie said PLA, EVOH and Eastman’s East One water dispersible copolymers are contenders, but often require a temperature-separated bicomponent spin beam to run in combination with polypropylene.
Thermoplastic polyurethane elastomers such as those supplied by Kraton, Exxon’s Vistamaxx and Arkema’s Pebaxalso need a thin sheath of polypropylene to prevent tackiness. For meltblowing they also require high pressure die assemblies.
Other polyesters such as PBT, PTT, CoPET and PA11, along with the high temperature and corrosive polymers such as PPS, SABIC’s Ultem and fluoropolymers are also capable of being converted on Hills equipment.
For the newer polymers, new spin beams featuring the ability to run two polymers at different temperature to the same spinneret holes with equal polymer melt residence times, and a high-pressure capability cf PP (i.e. 10,000 psi) are required and available.
