Paper innovation ramps up with NANO-CHEMISTRY
By Pulp & Paper Canada
By Pulp & Paper Canada
Responding to market needs has always been a driver in Canada, but the focus on brand development and responding to unique customer needs has never been greater. With the move to high speed digital pr…
Responding to market needs has always been a driver in Canada, but the focus on brand development and responding to unique customer needs has never been greater. With the move to high speed digital printing, increasing expectations for sharp color images, growth in home office printing, and innovations in hybrid packaging and displays, papermakers are looking inside the process for greater flexibility and innovation.
According to Bob Eamer, senior vice-president, technology development and expansion, Domtar, “To support customers differentiation, we are adapting the process of papermaking. Nano-technology is a valuable tool to create new possibilities…to build a platform to add other things on top, including metals and plastics. By digging deeper into papermaking itself, we can help support entrepreneurial efforts.”
Eamer notes that with nano-technology the industry has just scratched the surface. In addition to retention/drainage systems to improve the base sheet and new “proprietary” formulations to open the way for coating, he suggests that chemical process innovations can help with other issues like minimizing corrosion and erosion.
Eamer believes that nano-chemistries and other approaches in coating technology will allow easier shifts in grade changes also. “At Domtar we see mass customization occurring, where we run machines like commodity processes, but make constant changes toward the end. Enhancements at the size press or the end of the paper machine near the coating section will happen more frequently.”
Nano-technology has colossal potential for all industries, not just paper, according to Richard W. Siegel, the Robert W. Hunt Professor of Materials Engineering at the Rensselaer Polytechnical Institute in Troy, NY. Siegel refers to nano-technology as the basis for a “second industrial revolution”. He says, “There are major opportunities for nano-particle technology for paper itself, the papermaking processes, and the raw materials going into paper. Paper has great potential to recreate itself as a versatile end product. In addition, raw materials, seals, felts and more will change dramatically because of our greater nano understanding. Work systems will change, too, as people will be part of this revolution.”
Louise Raymond, paper mill chemist at Domtar’s, Cornwall, ON, mill also sees the potential for tailoring base sheet and coating chemistries to respond to the needs of customers. She says that, “With the application of nano-particle technology at the wet end, you are adding ‘little beads’, effectively more surface area, available for reaction. So you can use less chemical, and get more bang for the buck.”
Raymond also speaks about the benefits of simplifying the chemistry for productivity and environmental reasons. “As we run more closed systems, it’s important to minimize the amount of chemicals used, and be sure they are working in concert. When chemicals work together, there are fewer deposits, and fewer complaints from customers concerning quality issues. When a good retention system helps you send chemicals out of the mill in the paper, there’s also less waste treatment.” She stresses that it’s also a good idea to seek practical mechanical solutions to day-to-day problems, and to reduce the number of chemicals or the dosages whenever possible.
Richard Gratton, Domtar’s technology development manager, believes that nano-particle retention/drainage systems have become more accepted, and are becoming more specialized. He notes that, “Now there are particles to go in between, and even more powerful ones coming. Colloidal silica has opened many doors. We also use bentonite, and new high-degree substitution starches to further optimize papermaking.” He also considers on-site “smaller particle” liquid silicate generators as having a future.
According to Gratton, sizing and the size press as playing a greater role in producing desired surface properties, too, and positively impacting the process. He believes that ASA has won the war as a lower price option to AKD for communications grades, allowing filler at 24% without a problem. He comments that SAE (styrene acrylic emulsions) are most effective surface agent for these grades, but believes there is room for other surface sizing chemistries, depending on the objectives.
Gratton sees significant potential for coating at the size press, including the use of broke with some coating in it. He adds, “We need robust chemistry at the wet end when faced with broke with latex, pigments, and anionic particles. Chemistry is not a barrier to meeting objectives like improved printability. People are willing to pay for more snap for ink jet and laser printers.”
When asked why Canada tends to play a leading role in pioneering nano-particle and other chemical technologies, he cites Canada’s mindset to be competitive. “With Canadian dollar low these days, but going up one day, we need to be ahead. We need to always be open to new things. When you are second or third in the world market, being open to innovation helps you gain a competitive edge.” Gratton compliments the role of government in pulp and paper research, including the new coating facility in Trois-Rivires, QC.
A record of success
Russ Gladun, technical manager at Domtar Eddy’s New Westminster, BC, mill (formerly Island Paper), states that silica nano-particle technology has been used for high-performance retention/drainage for over 10 years and continues to evolve. It all began when the mill went alkaline, after a comprehensive study and trial plan. Gladun insists that forward planning is essential when considering advanced technology, and that support from strategic suppliers is a must. “Everyone needs to understand that success comes from a joint effort. The chemistries are interrelated and, as such, all of the parties involved must work together to overcome any problems that arise.”
He comments that retention chemistry has advanced, moving to finer particle-sized colloidal silica. “We feel we picked the best of the best, but a range of suppliers are now offering good products in this area. A lot of across the board learning has advanced the technology.”
Now that most of the mill’s production is coated grades, it continues to fine tune the system. Gladun adds, “Our intensive efforts to create the best possible base sheet was critical to the smooth launch of the coated line. We built a very competitive product– always a high quality coated product, right from the start.” When asked about revisiting wet end chemistry, Gladun indicated that in 2001 the mill will be evaluating potential retention chemistry improvements to capitalize on the advances in nano-particle retention chemistry.
A supporting voice to nano-paper innovators is Phil Jones, vice-president, technology, for IMERYS, a multi-pigment minerals supplier. Says Jones, “Better imaging capabilities allow us to see the nano-scale texture of fibre and other components that comprise paper and its coating, giving us the insights for future grades.
“Because we can see nano-structural configurations, we can adapt the fundamentals, and then, through diagnostic applications based techniques, see if they worked. Next, we can rethink the design of the basic building blocks. Nano-technology developments in areas of fibre science, minerals and other additives give us a new means to put order and structure into the designs of a sheet.”
According to Femi Kotoye, technical service and development manager for Emulsion polymers for paper coating with Dow Chemical Company, the performance of latex for paper coatings can be raised dramatically through nano-technology.
He says that with nano-technology, you can dial in the properties you are looking for. This makes it easier to sequence polymer. An example of this is the building of a latex particle with non-random sequences. Says Kotoye, “With nano structures you can make a polymer with the inside hard, the outside soft, and by adjusting the thickness, one can build a polymer with improved opacity and
“With nano structures we can build better adhesives for the paper coatings, which will give higher strength paper coating surface. This will allow the printer to use higher tack inks. Stronger inks gives you pictures that jump at you.” As for lighter basis weight papers to lower postal costs, Kotoye suggests that with nano-technology, polymers can be built to have better stiffness and opacity and lighter weight.
Chalmers Reed, northeast regional sales manager with Eka Chemicals, Akzo Nobel, the company that introduced the first nano-particle retention system two decades ago, also sees the focus shifting. “Just as silicon chips have packed more power in computing, advanced silica nano-particle technology systems can now do more, across a broader range of applications. Before the focus was on retaining filler as a cost savings. Now we are part of the team to develop entirely new grades.” Another change in nano-chemistry, says Reed, is the growing synergy with other chemistries and additives. “Building on a superior base sheet, papermakers can now seek more from coating. Expect to see great strides in coating over the coming decade.”
Martin Koepenick of Innova International can be reached at firstname.lastname@example.org. He writes frequently about trends in the paper industry, interviewing industry executives and visiting mills around the world.