Metso Paper to launch new paper and board coating technology
Published Mar 15, 2001 00.00.00 +2 GMT
As the result of years of intensive development work and customer cooperation, Metso Paper is now ready to introduce its new OptiSpray coating technology to the market. This new process for improving the coating of paper and board, and also printing properties, cannot be matched by any other paper machine manufacturer in the world.
The OptiSpray coating process is based on a controlled, high-pressure spray application of coating or surface size directly on to the surface of paper or board without any direct machine contact. The coating is simultaneously sprayed (atomized) at high speed on both sides of the paper web.
OptiSpray achieves excellent coverage of the base paper. This is because the spray application spreads the coating evenly over the paper surface, uniformly covering uneven areas of the base paper with an even coating layer of the desired thickness.
The process facilitates the development of new paper and board grades, or the improvement of coated-paper grades produced with traditional methods. For example, OptiSpray can improve the quality of newsprint to the extent that its surface properties are almost equivalent to those of magazine paper.
OptiSpray benefits paper and board manufacturers
The spray-coating station can be situated on the level of the paper machine, in the normal way, or alternatively below the paper machine in the basement, which will bring significant space and cost reductions in machine rebuilds.
The process will also significantly lower running costs, as it is automated and contains only a few consumables or components that need regular maintenance. There is no need for the blades, rods or backing rolls of traditional methods that cause runnability problems.
Raw-material costs are also reduced because the process allows for lower MD paper strength. This makes it possible to use recycled pulp, for example, as the raw material.
OptiSpray can be used for high speed coating. In tests conducted at the Technology Center in Järvenpää, Finland, paper was coated at a speed of up to 2 500 m/min with the paper web moving at a phenomenal 150 km/h! At this time the world’s fastest production machines, supplied by Metso Paper, currently achieve production speeds a little above 1 700 m/min (over 100 km/h).
The process has been extensively tested. Machine runnability, process operation or paper quality exceeded the targets. This provides paper manufacturers with an opportunity to achieve higher capacity utilization in comparison to present paper coating technologies.
A step forward in paper manufacturing
OptiSpray can be regarded as an extremely significant step forward in coated-paper manufacturing technology. Numerous pilot runs and trial coatings on various base papers conducted in cooperation with paper manufacturers have exceeded expectations. A development team in Metso Paper’s Coaters and Reels unit situated in Järvenpää, headed by Vilho Nissinen, has been responsible for the OptiSpray technology.
Negotiations on the delivery of the first OptiSpray equipment for production purposes are currently underway.