Successful implementation of MARE yankee coating technology on state-of-the-art tissue machine

Dear Reader of Tissue MAG,
We are glad to have this space on TissueMag to update you about our latest success in the implementation of yankee coating chemical programs on world top level tissue machines.

More specifically, MARE was selected as a key supplier for the start-up of a high speed double size tissue machine, equipped with a crescent former section, suction roll, shoe press, cast iron yankee dryer and mist removal system. The goal of their customer was to produce high caliper soft tissue paper at a target speed level up to 2,000 m/min. MARE took part in the full and careful implementation of the yankee coating equipment and yankee cylinder pre-conditioning. The start-up was very smooth, good quality paper was achieved from the very first roll and it was possible to shift to the use of low beavel ceramic blades quite soon. Now, let’s have a glance to the coating chemical package which was used.

MARE’s products and technical expertise demonstrate optimised cost solutions ensuring reduced costs, increased flexibility and increased competitiveness

MAREMOD P 600: selected as protection aid to provide long term preservation of the yankee surface from erosion and corrosion. MARERELEASE R 250, synthetic release agent: was made part of the recipe in order to provide a well controlled sheet doctoring and proper softness and caliper development of the tissue sheet. MARECOAT A 598: filming agent which provides a soft and stable adhesive coating layer, based on an innovative polymeric chemistry, thought for modern machines and for the production of premium tissue paper grades.

The nature of MARECOAT A 598 provides unique properties such as stability on “cold” Yankee cylinders and in presence of uneven moisture profiles while maintaining a soft coating layer. The development of the newest family of products MARECOAT A 593/595/597/598 started more than two years ago with a careful lab selection of various polymeric bases. The parameters taken into account for the selection were film softness, adhesion strength in dry and wet conditions. The lab selection, performed in accordance with a top tissue making company, with production sites located near to MARE offices, was followed by a comprehensive plant test were the excellent performance of this family of coating chemicals has been exhaustively assessed.

The yankee coating package was completed with MAREMOD M 470, edge control chemical, applied when needed on the out-of-hood section of the yankee in order to control coating build up in this part of the machine.

Mare’s products and technical expertise

During the start-up and subsequent adjustments, MARE yankee coating chemical program has been subject to quite extreme conditions without losing film stability, such as uneven moisture profile with wet sections higher than 10% and, for short periods, to 12-13%, all this at high speed and with the regular use of low beavel ceramic blades. Noticeably, it was possible to obtain target softness values without the need for drier paper and without the addiction of a softener. Softness results have been assessed by TSA measurement up to values of HF 100.

It is important to mention that a very high “creping efficiency” has been reported soon with the first rolls as well, defined as the ratio between the elongation measured on the finished tissue paper and the “creping ratio” on the machine. The papermaker can exploit high creping efficiency to reduce crepe ratio, that is increase pope reel speed with the same yankee dryer roll, so growing production while increasing mechanical properties and save on refining energy or paper formula due to the increase of the basis weight of the paper sheet prior to creping. Excellent stability to acidic conditions (pH 5) was also observed.

The supply package of the tissue machine where MARE coating chemicals have been applied, included a state-of-the-art system for the recording and analysis of the vibration behaviour of the Yankee blade system.

This system allowed a careful optimisation of the coating dosages allowing a deeper understanding of the coating layer behaviour.
Dear TissueMAG reader, we hope this article has provided you with some relevant pieces of information about MARE latest development in tissue making. If you want to know more, please contact your local MARE representative.