VIB systems
Market leader in the supreme discipline of moisturizing applications for specialty papers
In the production of specialty paper, numerous production parameters must be fulfilled with regard to quality, stability and flexibility. An essential process step is paper finishing. Precise application of a very small amount of water is required to achieve the desired paper quality. Improving the sheet’s moisture properties is one of the most effective and economical means of saving fibers and energy. ANDRITZ is a market leader in this supreme discipline of moisturizing specialty papers.
Focus on decor paper
Innovative paper applications nowadays include the growing use of decor paper. Decor paper is rotogravure color printed with a wide range of imitation wood graining, masonry textures or other patterns. Then the paper is impregnated with resin and pressed onto the chipboard surface. For this application, the paper requires special and exact properties: dimensional stability with good ink absorption together with uniform resin penetration and excellent printability. High opacity is also necessary for adequate covering of the base material. To achieve excellent printability, a high degree of smoothness is needed on the paper surface, achieved by means of soft on-line calendering with a soft or multi-nip calender. Due to the large number of resins for wet strength, the paper is bone dry when it leaves the dryer section. To obtain the requested surface and print qualities with this calendering, it is essential to remoisturize the paper.
Benefits
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High-precision steam dosing
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Application from the top or bottom side
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High-velocity steam, specific temperatures and impingement times
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Custom-designed control zones across the web
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Optimal sealing of steaming area
VIB MoistureTech – improving the sheet’s moisture properties
Decor paper with a high-freeness stock and ash content of 50% must be remoisturized with steam. The paper should have a temperature of 40°C when it leaves the dryer section so two cooling cylinders are needed at the end of this section. In physical terms, cold paper guarantees the highest level of remoisturizing.
Two important points must be considered when remoisturizing with steam: The steam must be distributed uniformly over the surface of the sheet and also be absolutely droplet-free. VIB MoistureTech is a versatile system for remoisturizing and increasing the temperature in sensitive paper grades and was specially developed for this application. Controllable zones for steam application guarantee that the paper surface has uniform smoothness and gloss profiles, and they operate 100% droplet-free. Additional dwell zones ensure highest efficiency for remoisturizing, and 3% additional moisture can be obtained easily before the calender. The design criteria allow the VIB MoistureTech to be installed between the dryer section and the calender in a vertical or horizontal position. MoistureTech is not only used for decor paper but also for remoisturizing and curl control on laminated grades and silicone papers.
