Kemform is a new, multicomponent retention technology that improves fines retention and enhances formation. Using Kemform, a mill can increase its filler usage by up to 2–3% without any loss in paper strength.
 “With the help of the new system, a fine paper producer can increase his use of calcium carbonate, for example, without compromising on end-product quality or having to use additional chemicals to strengthen his paper,” explains Marco Polverari, one of Kemform’s developers.
The new technology is equally suited to wood and woodfree paper, and is already in use at a number of mills in North America, Europe, and Asia. Marketing the product worldwide has now started.

Fully customizable to a mill’s needs

Kemform is offered in three configurations, featuring a cationic or anionic micropolymer combined with colloidal silica, bentonite, or cationic microparticles. A separate flocculant is also part of the package.
Kemform is a total solution, including dosing equipment and mill-specific engineering, says Polverari.
“Kemform represents a completely new approach to improving retention, formation, and drainage. The innovative parallel use of inorganic microparticles and an organic polymer is a special feature of the technology, which can be tailored to a wide variety of production conditions. Although the components of the system represent tried and tested technology, they have never been combined in this way before.”
Kemira’s new Fennosil E micropolymer technology, for which a patent has been applied for, lies at the heart of the new system. The highly water-soluble droplets of this new micropolymer include high molecular weight polymers in a coagulant mix.
“Thanks to the use of advanced production technology, we’ve been able to incorporate two active ingredients in the same suspension, rather like a striped toothpaste,” laughs Polverari.
“The active ingredients work very well together and take care of both micro- and macroflocculation. This means that fines attach themselves to the surface of fibers very effectively, resulting in excellent formation.”
Development work on the new micropolymer began in 2001. At this stage, however, the synergy potential between a micropolymer and silicate or bentonite was not understood. The key innovations that led to the multicomponent approach of the resulting technology were only made five years later.
The Kemform system was developed and trialed for around two years until it was given the green light for production. The technology’s multicomponent nature makes it very customizable to the needs of different customers, says Polverari.
“As the system consists of three components, this allows us to regulate retention, drainage, and formation separately. We can also control filler content, strength, and other paper properties that are dependent on furnish composition.”
All in all, the system offers mills much better potential to manage their pulp mix than traditional methods. “We can manage the pulp mix – fiber, filler, and fines – on the paper machine completely independently, in effect decoupling them from each other. In addition to this better control, the beauty of the Kemform system is that fillers adhere to fibers really well, enabling fibers to be more tightly grouped together. This means that they’re more evenly distributed through the web, resulting in stronger paper,” explains Polverari.

Good savings potential

Kimmo Strengell says that the new system has been very well-received by customers, as it offers the opportunity to save on costs and produce a better end-product.
“A Kemform project will normally take between three to four months, from when we’ve shown that the system is functioning as it should in the laboratory to mill-scale running. The laboratory tests, machine modifications, and other trial arrangements all take their own time.”
Trial runs generally last one to two months, or one wash cycle, to ensure that the system can be fully evaluated. These trial runs do not involve any production-related risks, however, or do they affect day-to-day mill operations.
“In our most recent Kemform trial, we increased the proportion of filler, or PCC in this case, in the copy paper being produced from 21% to 24% – at a mill that has never run at over 21–22% PCC content before.”
The impact of a change in retention system on other processes is always analyzed at the start of a project. In many cases, the need for other chemicals, such as starch, will be reduced.
“We start off by looking at a machine’s mechanical limitations in terms of its wire and rollers, and the content of the pulp being used. We have to understand how the system can make money for the customer,” says Strengell.
“A 1% increase in filler usage on a large fine paper machine could well mean savings of around a million dollars a year, and improve printability at the same time. We’ve got very good feedback on improved strength as well. Strength and improved drainage seem to be inter- related here.”
The savings achievable in sizing and strength chemicals are generally sufficient to pay for a project.
“For some customers, better runnability has made up to a 16% increase in output possible. The revenue this generates goes straight to the customer’s bottom line.”

Kemira Solutions No. 3/2007

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