Leverkusen -- Radiation-curing, water-based polyurethane
systems for wood finishes are both economical and environmentally friendly.
They cure very quickly under UV light, which means that the finished wood
can be stacked immediately it leaves the production line. Apart from that,
the systems contain little or no solvent apart from water, so they emit
only minimal quantities of volatile organic compounds (VOC). Bayer MaterialScience
AG has recently introduced a number of new polyurethane systems of this
kind to the market, the latest being Bayhydrol® UV XP 2420. "We
now have a tailor-made polyurethane system for outdoor applications,"
says Dr. Christoph Irle, the expert for polyurethane wood finishes at
Bayer MaterialScience. He sees window frames and shutters, doors and all
kinds of exterior wood paneling as potential applications. The finishes
may be either transparent or pigmented and are highly flexible, even at
low temperatures. They also have very good chemical and mechanical resistance
properties. Above all, however, they are noted for their outstanding weather
stability. Their chemical backbone is formed by special aliphatic polyurethanes
that remain virtually unaffected by sunlight.
UV-curing, water-based polyurethane systems for wood finishes based on Bayhydrol UV XP 2420 from Bayer MaterialScience are particularly suitable for exterior wood paneling, as they are characterised by an outstanding weather stability.
Bayhydrol® UV XP 2420 is very easy to apply. It dries
on wood within a few minutes. After this, it takes only a few seconds
under UV radiation for the finish to cure. "This makes for maximum
productivity, which is a major advantage over other solvent-based and
waterborne outdoor wood finishes," says Irle. But it is not only
the wood-processing industry and its customers that will benefit from
this economical, environmentally friendly, weatherproof system. It also
adheres very well indeed on metals and plastics.
UV-curing polyurethane dispersions of this kind are experiencing
high growth rates on the world market, mainly because there is no need
for the user to mix the polyol and polyisocyanate before application,
making life that much easier. At the same time, the coating system is
able to meet particularly high quality requirements, thanks mainly to
the subsequent crosslinking of the polyurethane molecules under UV radiation.
In addition to the new product for outdoor applications,
Bayer MaterialScience also has its proven product line centering on Bayhydrol®
UV VP LS 2282. This universal grade is suitable above all for clear and
colored primers and topcoats. Other products include Bayhydrol® UV
VP LS 2348 and Bayhydrol® UV VP LS 2280. The former is noted for its
outstanding adhesion on critical' wood types and its ability
to accentuate the wood grain, which more or less predestines it for use
on furniture and parquet flooring. The other product was developed specifically
for pigmented formulations and also adheres very well to metal. Last but
not least, there is Bayhydrol® UV VP 2317 which is characterized by
its excellent wet film transparency, which means that it is also clear
during application, and can be re-emulsified without problem. The latter
property is an advantage above all for recycling the overspray, which
can be collected easily with water or coating material and returned to
the coating cycle.
Source: Bayer MaterialScience