Retention and Drainage

Abstract

As the paper and board industry continues to increase the speed and output of paper machines, the demands on retention and drainage aids are increasing greatly. Increased shear forces at the headbox and on the wire and ever shorter dewatering zones can be incompatible with the need for good runnability, high quality and good formation. Increased water system closure and increased water temperatures are also altering the environment within which the retention and drainage aid has to function, requiring an alternative approach in many cases.