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At the heart of efficient papermaking – Quick inversion polymers

As the speed of paper machines increases and recycled fibers are more and more used as the raw material in papermaking, the demands for machine cleanliness and retention and drainage performance increase as well. Kemira introduces new quick inversion polymer technology that helps paper and board producers to tackle the challenges of modern papermaking and improve production efficiency, product quality, and productivity.

“Polymers used as retention aids and fixatives in paper, board, and tissue manufacturing have a key role in efficient papermaking,” states Arno De Beer, Senior Manager, Global Business Development, Retention and Strength at Kemira Pulp & Paper.

“Retention and drainage performance has a clear impact on both productivity and on product quality, maintaining overall paper machine runnability. Same goes for pitch and stickies control: if the contaminants are not retained properly, the manufacturers suffer from paper breaks and deposits, reducing product quality and production efficiency.”

Kemira introduces new quick inversion polymer technology to help improve papermaking efficiency. In this article, our experts share three ways in which the new multipurpose polymers help bring considerable benefits to the paper, board, and tissue manufacturers.

Solving the tricky stickies control challenges

Firstly, the new polymer technology helps address one of the costly concerns particularly in recycled paper and board production: stickies that originate from tapes, glues, and labels used in recovered and recycled packaging material.

“Efficient production of paper and board using secondary fibers requires special attention to machine cleanliness. If the contaminants are not managed correctly in the process, they will significantly impact the operational efficiency, reducing runnability and impairing product quality,” says Michael Wallace, Senior Manager, Wet End Applications at Kemira Pulp & Paper.

Stickies are tacky particles, e.g. hot melt adhesives such as vinyl acetates, that can form deposits in the paper machine and on the forming fabrics and dryer felts, necessitating machine downtime for maintenance and clean-up. When the sticky deposits end up in the paper sheet, they cause web breaks and product defects, such as holes and dark spots.

“Quick inversion polymers work well in stickies control, thanks to their superior hydrophobic particle fixation capability. Manufacturers producing recycled grades know how difficult it is to find a high-performing stickies control solution that is also easy to apply, cost-efficient, and compliant with modern regulatory demands, e.g. suitable for use in food contact. These new products tick all those boxes.”

A cleaner process means immediate efficiency gains: a 100% recycled linerboard mill was able to increase machine production over 2.5 tons per hour.

A cleaner process means immediate efficiency gains. Michael shares a recent customer success. A mill using 100% OCC pulp to produce recycled linerboard was suffering from sticky contaminants that agglomerated mainly in the dryer section of the board machine and caused sheet defects, holes, and web breaks.

“With our quick inversion polymers for stickies control, the cleanliness of the dryer section improved considerably, and the mill was able to increase machine production over 2.5 tons per hour on lightweight grades. Another good example comes from a mill producing recycled tissue grades. Improved stickies control helped reduce defects in converting and what’s more, dramatically improved their machine’s creping blade life.”

Dewatering at the heart of efficient papermaking

Secondly, quick inversion polymers are effective as retention and drainage aids and improve dewatering. The higher molecular weight combined with high charge helps boost retention and drainage performance.

“Optimizing retention and drainage is at the heart of efficient papermaking. As the operating speed of the paper machines increases, the importance of retention and drainage performance has increased, and so have the related demands,” Arno states.

Improved dewatering performance in the forming section brings many benefits, impacting the quality of the finished sheet and overall paper machine runnability. It can also help increase resource and raw material efficiency, e.g. through reduced steam usage and thus, decreased energy consumption, or through improved retention of furnish components.

Improved dewatering performance at the paper machine helps increase resource and raw material efficiency.

“The technology has proven to improve first pass retention (FPR) of fines and fillers e.g. in high-grammage paperboard grades. A customer producing white offset and bag grades was able to increase FPR from 34% to 59% while maintaining sheet properties,” Arno mentions.

Increasing the cost-effectiveness of the chemical solution

Thirdly, quick inversion polymers help improve the efficiency of other functional chemicals in the papermaking process, such as sizing agents and other wet end additives. “Again, chemical efficiency impacts the entire wet end performance and paper machine runnability,” Arno says.
An additional key benefit is that the quick inverting emulsion polymers do not require similar aging time as traditional polymers. This eliminates the need for complicated and costly make-down equipment and storage tanks at the mill site.

“This further increases the cost-effectiveness of the chemical solution for our customers. And it’s not just about the chemicals, but also about the application expertise. We utilize advanced chemical injection technology and digital solutions for e.g. monitoring hydrophobic particles and chemical performance in real-time, which enables efficient and optimized processes for our customers even in challenging production environments,” Michael concludes.

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Quick inversion polymers for stickies control

As paper and board makers continue to use more recycled fibers, they will increasingly need stickies control to ensure machine cleanliness and runnability. A new family of acrylamide-based quick inversion polymers are shown to be highly effective at removing sticky contaminants.
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