Cologne — Lanxess will showcase a number of low-free isocyanate prepolymers from its Adiprene LF and Trixene product lines at the European coating show.
The company said that it produces its low-free prepolymers by inserting a vacuum distillation phase after the initial polymerisation of the polyol and the diisocyanate.
Lanxess said that vacuum distillation removes the residual monomeric diisocyanate from the final polymer. This enables the company to produce prepolymers that meet stringent environmental and workplace hygiene regulations.
Typically, the low-free prepolymers have 0.1% by weight of free diisocyanate, the company said.
It added, that the prepolymers should be attractive building blocks to formulators and offer reduced hazard classifications. The EU’s proposals for diisocyanate restriction could make them more attractive, Lanxess suggested. It may be possible to avoid costly and time-consuming measures needed for other diisocyanate systems in the European Union, the company continued.
Lanxess went on to say that the materials have a narrow molecular weight distribution and their viscosity is precisely adjustable. These factors help generate finished polyurethanes with optimised properties and improved processability.
Moreover, the prepolymers also have better defined regions of crystallinity than their predecessors; this helps make high quality and durable films.
Adiprene LFH materials based on hexamethylene diisocyanate will be centre stage at the show. Long-lasting, high-quality outdoor applications may be a suitable home for them.
In addition, the company will be discussing its Trixene prepolymers. These are based on isophorone diisocyanate. Industrial coating applications which require high resistance to both weathering and chemicals could be good applications, she added.
Wind turbine blades could be one potential market for the new materials, said Julie Chapelet, global strategic marketing manager. These are exposed to a variety of stressors such as UV radiation and erosion.
The offshore sector could be a good home for the coatings. This is a tough environment, where maintenance is hard, said the company.
For example, raindrops and solid particles hit the blades at relative speeds of 300 km/h (200 mph), when the rotor blades length exceeds 100 m.
In addition, the leading-edge of the rotor blade requires special protection to prevent serious damage or even material failure, she said.
Nuremberg, Germany is hosting the European coating show between 19-21 March 2019.