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The Nanonomics Equation For Value-Added Paper


May 1, 2007
By Pulp & Paper Canada

Whatever paper and board has been for 2000 years, there is now the potential to produce better products more cost effectively. The combination of nano science and economics are transforming process pe…

Whatever paper and board has been for 2000 years, there is now the potential to produce better products more cost effectively. The combination of nano science and economics are transforming process performance and end products.

Without a lot of fanfare the last decade of nano related advances are impressive: Coatings are multi-dimensional — thinner, smoother and brighter.

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Composite base sheets are mineral-rich, reducing the expense of fibre.

Many grades are lighter weight, yet stronger. Papermaking is cleaner, greener and more energy-efficient.

When you calculate the savings in fibre alone from filler substitution and lower basis weights, savings are in the billions. This is not figurative language, but a fact. A simple calculation of productivity gains on machines around the world, combined with fibre savings, supports this claim. Add to this a consistent increase in quality and the ability for some grades to command a premium price, and we’re seeing a different kind of paper industry.

Some would argue that these advances would have happened without nanotechnology. Some still see nano as the new sex appeal word, simply re-naming progress in materials science and the application of existing technology. More accurately, these trends began many decades ago, before the advent of the Internet!

In addition to paper scientists, however, an increasing number of industry leaders see nanotechnology as integral to process and end product gains.

Says Greg Bengtson, VP Marketing Eka Chemicals, “Nanoparticle retention aid chemistry has improved the properties of paper and board in many applications over the last 20+ years. By improving the sheet formation and enhancing filler distribution these silica sol nanoparticles in combination with starch and/or polymers can rightly claim a vital role in ever more efficient papermaking, which delivers enhanced properties for printing, converting, packaging and consumer products raising the value of the papermakers products.”

Mike Bilodeau, director of the University of Maine’s Pulp and Paper Process Development Center, sees a key role for nanoparticle science in the forest products industry. Says Bilodeau, “The tree is a remarkable example of a natural nanoparticle factory producing enormous quantities of nanocellulose, a sustainable raw material that we are only beginning to learn how to isolate and incorporate into new products. This technology could have a dramatic impact on future forest management practices, public policy and recycling strategies.”

Phil Jones, director of technical marketing & new ventures at Imerys and co-chair of AF&PA Nanotechnology task force, notes that the momentum continues to build in the U.S. and the forest industry. He reports that the Agenda 2020 program has been well received by government agencies, who salute the forest products industry as knowing its technology needs.

Says Jones, “The Nanotechnology Task Force has engaged government agencies through a CBAN (Consultative Board for Advancing Nanotechnology in Forest Products), where we will work closely together to capture and apply nano developments. Our sector can bring natural products to the nano world, utilizing cutting edge technologies to better understand wood fibres and minerals.”

Pushing properties o peak performance

The potential for adding greater value to paper and board is considerable. A short list of advances underway follow:

End product enhancements:

* Water repellency

* Mold resistance

* Ink jet image quality

* Smoother printing

* Insulating gains

* Sensor embedding

* Safer hot beverage cups

* Microwavable packages

* Sustainability of paper and aligned industries

* Futuristic fireproofing & bulleting-proofing too?

Process efficiency initiatives

* Further reduction of raw material costs

* Greater flexibility of raw material ratios

* Water purification

* Biodegradability

Nano base sheet and coatings basics

According to Tony Lyons, director of applications technology for Imerys Pigments for Paper, “Innovation is closely tied with advances in papermaking, coating equipment and control, especially our ability to understand the components of paper and end products on a nano level.” Lyons believes that our ability to see the 3-D reality of the sheet, including nano scale particles of raw material that work together to create today’s composite sheets, are the foundation for higher performance and lower costs.

Commercial snowball effect

Many believe that advances in the science of nanotechnology are beginning to snowball, and will pay off in the near term. Nano is reaping rewards outside of the paper industry and so why not in it? Many have heard about new golf balls, tennis balls, tennis rackets, sunscreens and such. Papermaking wet end retention aids have long been “nano.” So, what’s next?

Look for strides in coating, as coating chemists and engineers have been on the frontier of nanoscience for some time now. Changes in pore structure are now possible on a nano-scale, and can result in major changes in optics and printability. Pigments designed on a nano-scale will one day result in improvements in paper strength. Continues Lyons, “We have discovered that kaolin pigments that are under 100 nanometers in thickness will have improved stiffness over conventional kaolin pigments in many coating and surface pigmentation applications.”

Also look for continued progress with nano-engineering of coating components, facilitated by latex binders. Nanostructure-based adhesives can deliver producers higher strength paper coating surface to improve printability, especially when higher tack inks are used. Latex nano structures are now commonly built to enhance various paper properties, such as stiffness and opacity for a range of increasingly lighter weight grades.

Out of Africa

Sappi is taking nanotechnology very seriously. “Ours is a mature industry whose survival depends on new products and processes for the 21st century,” says Sappi senior research scientist Vinotha Bheem. “Nanotech may be the light this industry has been waiting for.”

In South Africa, just as it is around the world, the paper industry is under pressure. Environmental risks and impacts caused by liquid effluents, air emissions, solid waste, heavy resource consumption and recycling are an increasing part of the cost of doing business. At the same, time pricing pressures from large retailers and increasing costs of raw materials and energy are a concern. Looking at the grand view of revitalizing the paper industry, Bheem notes that they have taken a holistic view toward positive change, from the forest, to improved processes, clean water and new product development.

Sappi is currently evaluating nanosensors to measure moisture and temperature, because they believe that nanoparticles and polymers can reduce the cost of treating water. “We can improve recycling through better utilization of natural resources and by reducing the amount of solid waste, without sacrificing cost and quality. This means we need to find ways to remove ink and contaminant from waste paper and develop a recyclable glue.”

Papermaking processes can be improved, says Bheem, by increasing machine efficiency and decreasing energy consumption. Developments in nano silica and in nano coatings and additives mean that high-gloss papers can be developed more easily and efficiently. Other materials can be layered onto the underlying paper matrix, creating a product that acts very differently from other papers.

For Sappi, nanosensors implanted in trees could improve the management of for
ests (by providing early warning of disease, for example), while nanoparticles could improve the efficiency of the papermaking process while reducing the production of pollutants. Nanotechnology could also improve ink and pollutant removal from waste paper. Further, nano coatings could result in water- and oil-resistant paper (imagine it — waterproof paper) while nano inks could allow the printing of low-cost electronics into paper.

Also of note at South Africa’s University of Cape Town physics department is the development of a new way to print low-tech electronic circuits onto paper using nanoparticles of silicon suspended in ink. The applications are broad, extending from active packaging with animated pictures to package sensors, which change colour when the contents are altered.

Mondi’s splash of nano in Europe

A big splash was made by Mondi’s European business paper group with the launch of “neox,” which they call the ?rst paper to be manufactured using nano-hybrid technology.

Through the innovative application of this technology, they claim a marriage of the best of coated and uncoated paper in one sheet. The stated result is a revolution for professional colour laser printing.

“By utilizing nano-hybrid technology, we have achieved a breakthrough in paper production. Our neox brand will revolutionize the colour laser printing market. It is a paper more versatile than anything on the market to date,” explains Gnther Hassler, CEO of Mondi Business Paper.

Neox has the glossy and tactile feel of a coated sheet along with the high whiteness and stiffness that you would normally expect from a quality uncoated product. Their marketing people suggest that the surface gives a “feel” that immediately suggests a quality print job. The high whiteness is typical of premium uncoated colour laser sheets, and yet neox combines this with the high tactile qualities of coated paper. Another feature of neox, normally expected only from an uncoated product, is its stiffness. Neox is said to provide printers with the possibility to use lower grammages with associated savings in paper costs and postage charges.

Domtar’s birth control for billions of microbes

Thinking small in another way, Domtar has focused on small and potent germs, and launched the first antimicrobial office paper available in North America. Designed to protect paper against the growth of bacteria, odours, fungus, mold and mildew, this product is specially treated with a silver compound that kills most bacteria that come into contact with it. Although conceived for general office use, the paper’s unique characteristics make it ideal for the healthcare, laboratory, hospitality, education and governmental sectors.

Laboratory studies show that one bacterium can reproduce into 10 billion bacteria in just 10 hours.1 Independent laboratory tests on Domtar Antimicrobial Office Paper demonstrate a 99% reduction of MRSA (Methicillin-resistant Staphylococcus aureus) and K. pneumoniae.2 The paper also inhibits the growth of bacterial odours, mold, mildew and fungus while maintaining the antimicrobial features throughout its shelf life, making it ideal for archival purposes. Additionally, Domtar Antimicrobial Office Paper retains its antimicrobial properties even after printing and varnishing.

“With the introduction of the Antimicrobial Office Paper product, Domtar is once again demonstrating its commitment to bringing innovative products to the market,” says Steve Barker, senior vice president, pulp and paper sales and marketing for Domtar. “The development of this paper presents an opportunity to help reduce the proliferation of bacteria in office environments.”

Given the significant increase in virulent bacteria such as MRSA over the past ten years, antimicrobial products are now sought throughout North America and, indeed, the world. While similar products exist in Europe and Asia, Domtar is the first company to bring an antimicrobial office paper to North America.

Domtar Antimicrobial Office Paper is manufactured under a licensing agreement with SilverCo, a developer of antimicrobial-patented technology. The antimicrobial compound has been registered with the United States Environmental Protection Agency (EPA) and approved by the Food & Drug Administration (FDA).

Nano card and graphics key

According to Alvin Kirbawy, Ph.D., R & D Manager at Simpson Tacoma Kraft Company, “To prevent serious water absorption problems on printing presses, and maintain consistent printability, high performance retention is a must.”

Kirbawy considers Simpson Tacoma Kraft Company’s ability to deliver crisp imagery closely tied to nanoparticle technology. In his words, “the nanoparticle retention system is critical to delivering top sizing performance, and also means that we deliver a very smooth white top liner, not a mottled sheet.”

Simpson Tacoma Kraft has played a leading role in helping fruit and vegetable producers revolutionize their look, and packaging quality. Printed graphics are considered a key part of growers’ marketing strategy.

Adds Kirbawy, “Even an apple box is heavily printed with 4-6 colours and varnish. That calls for high performance retention and sizing, which we have in place.”

Seeing more often is believing

There is widespread agreement that value properties such as opacity, brightness, gloss, print quality are manifestations of micro and nano characteristics. Established techniques like scanning electron microscopy have played an important role for paper scientists, but are expensive as a quality control tool. Now, new nano, con-focal devices and techniques are being employed to provide ways to understand how materials, formation and coating techniques interact to influence these properties.

Because these techniques are economical, accurate, quick and easily implemented, “libraries” of data can be developed to help the papermaker understand how unintended variances in paper surfaces, void volume, and depth influence print and other qualities. This is especially true for papers used for ink jet printing, rotogravure, and offset, where surface smoothness, void structure and depth have strong influence on ink and/or water absorption, and thus, print quality. Some felt suppliers have employed one product developed in Europe, based upon whitelight confocal microscopy, the NanoFocus surf.

Spray-ons, too

Moving beyond current coating technologies, or even re-creating existing technologies like the metered size press, look for nano spray-on coatings to go beyond sizing or gloss. We could see waterproof papers, superior thermal cups, disposable microwavable pulp or paper packages. And why not bullet proof and fire proof coatings? Maybe this sounds more like a dream factory than a paper mill, but don’t be surprised by bold gains in functionality.

Just as plastics and paints are leaping forward with “liquid solids” composed of extremely tiny particles with unique characteristics, so can paper.

Look for more frequent advances in paper performance, as the nano-economic equation advances the industry.


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