White top shines at St. Laurent

Pulp & Paper Canada
December 31, 1998
By Pulp & Paper Canada
There's change afoot at Montreal-based St. Laurent Paperboard Inc. The company doubled its size through the purchase of Chesapeake's West Point, VA, mill in mid-1997 and four corrugated container facilities in the US, and began a major product restructuring effort in the fall of 1998, focusing on premium mottled and white top grades. St. Laurent, already the largest producer of white top products in the North American market, will convert existing unbleached kraft liner capacity of 285 000 tons per year (tpy) to white top in 2000. Its total white top capacity will grow to almost 1 000 000 tpy. The mill at La Tuque, QC, will continue to produce to its capacity of 320 000 tpy of white top, but with an increased emphasis on high quality products, including some coated specialty grades. St. Laurent's stated intention is to offer a complete range of graphic linerboard grades to the industry, including white top, coated white top and solid bleached grades.

What follows is a report on West Point's adaptations to machinery and chemistry to improve efficiency and respond to market opportunities, and technology transfer shared with the La Tuque mill.

Upgrading the grades

St. Laurent's prime objective at West Point is not only raising the quality of existing grades, but to set a new standard for performance. For starters, PM 3's 352 000 tpy of mottled white linerboard has already improved in mottled appearance by a factor of three, a process that is anticipated to continue.

According to Andrew Woodroffe, director of marketing for St. Laurent's containerboard mills, "PM 3's TRI-LITE sheet has formation properties and strength superior to that of many white top grades. It is well known for its convertibility and printability. As for strength, the ring crush is among the best in the industry.

"When St. Laurent purchased the West Point mill from Chesapeake, we intended to raise the bar for graphic linerboard quality through technology exchange at West Point and La Tuque. The company started out with an advantage prior to the acquisition with West Point and La Tuque being considered the industry leaders in performance. In about one year, after considerable effort on the part of the West Point team, PM 3 has reached near white top appearance, at lower operating costs. About 18 months from now, PM 2 will become a swing machine capable of producing graphic quality unbleached kraft liner and white top products".

Bob Thieke, St. Laurent's vice-president, containerboard sales, notes that there's more to consider than just having white top being equivalent from one St. Laurent mill to another. "Meeting customer demands for scheduling and deliveries is equally important as the products themselves. While West Point and La Tuque will never be identical twins because of fibre differences, we fully intend to offer our products as alternatives to each other."

Thieke says that today's converter has shorter lead times to deliver a finished product. So, the supplier who can react quickly, maintaining a good inventory program and communications network, has an advantage.

Another factor in satisfying customers is a range of white board products. Thieke suggests that when a computer systems provider initially launches a product, the image created by the box can be more important than during the later stages of the products life cycle. "Our premium white top may be best for the launch, while our standard mottled product may be better later in the game."

To increase service to end customers, St. Laurent created a new sales and marketing entity in 1997 called St. Laurent Paperboard Corp, headquartered in West Point. The new team combined the talents of both the groups from West Point and the formerly Pennsylvania-based sales group of St. Laurent. The goal is to provide sales, marketing and applications knowhow to customers and prospects to produce better packages for a lower overall cost. This group supports St. Laurent's 11 converting facilities, as well as its large trade customers, which includes many of the major paperboard producers in the world. The group is supported by R&D in both Montreal and Richmond.

The difference

The difference between mottled and white top is increasingly fuzzy. There's no question that mottled is moving toward full coverage, or a white top in appearance. One distinction is that mottled usually has a lower brightness number. Premium white top grades tend to have 76 to 80 ISO brightness, while the standard white top grades fall around 68 to 72 ISO. The distinction between the grades is not solely linked to brightness but includes smoothness and printability, bringing added value to the customer. Thieke adds, "The real issue is the interaction of the substrate with ink and the quality of the resulting image".

Process changes

Two key advances are credited for much of the gains on PM 3. According to Larry Price, vice-president, operations, "Investing in soft-nip calendering equipment and changing the wet end chemistry allowed for significant gains in smoothness and surface uniformity. The mottled designation doesn't really apply anymore." Price suggests that a major fibre change, which they considered, probably would not have delivered more to the sheet.

An anticipated change to PM 3's wet end chemistry is a switch to alkaline papermaking for the top ply on PM 3 in the first quarter of 1999. Price points out that by running the sheet with less fibre and higher carbonate content, dewatering improves, which enables improved formation, producing a smoother sheet. This translates to better appearance and performance. Price acknowledges that alkaline papermaking has become common in Europe, so that the switch at West Point is by no means unprecedented. He adds, "We have switched one machine at La Tuque back and forth between alkaline and acid for 20 years. So we already had some comfort level in going alkaline in West Point."

Says Woodroffe, commenting on the sheet improvements, "We are taking our products to the next level. Our customers will continue to enjoy the print quality that they have become familiar with in using our products. This process change will allow us to continue to evolve our products as the market changes".

The three-ply PM 3 machine still follows the same structure for fibre, including a top layer blend of hardwood fibre, a middle OCC layer, and a base layer of virgin kraft fibre. The difference in the sheet's composition is its higher filler content. Price considers the use of less fibre and more carbonate pigments to be critical to their success. From a practical standpoint, this means improved appearance at lower chemicals costs.

The ongoing technology exchange with La Tuque aims to allow for product interchangeability. Price adds, "The primary challenge is to find ways to interchange our white top products, matching strength printability and appearance."

Beginning mid-year, preliminary work will begin for converting West Point's PM 2 from kraft linerboard to a white top linerboard machine, providing about 285 000 tpy. This two-ply machine, which will have soft nip calendering capability, will also run the top ply in alkaline conditions. Price suggests that "Alkaline papermaking will allow us to drive formation and strength to even higher levels, just as it has on PM 3."

A decision to exit market pulp production has already happened, and the mill will use the bleached fibre for the increased production of white top linerboard on PM 2.

With production changes at the West Point mill, the company will make adjustments within its forest products subsidiary as well. A new off-site processing facility will replace the current mill-site chipping operation. The facility will be constructed and operated by a third-party contractor to be selected later this year. It will begin operating in early 2000, under a chip supply agreement. As a result of this initiative, the company closed down its Elizabeth City, NC, chip mill and reduced other forest products operations in the fourth quarter of 1998.

Further gains

"We've only been evaluating an alkaline top ply sheet for the last quarter, so there's still gains to be made in sheet quality and efficiency as we better understand the system," says Price. "There's no doubt about the benefits from going alkaline."

On the market side, Woodroffe sees potential in making further inroads into packaging markets like point of purchase for displays in superstores and retailing in general, as mottled and white top grades move up in quality.

Adds Woodroffe, "Our additional premium white capacity, and increasing ability to interchange our white top from one machine to another, strengthens our market leadership position. It ensures the long-term viability of West Point and La Tuque through our ability to service our customers more efficiently. With this move, St. Laurent Paperboard is positioned to expand with products that have had historically higher margins and are projected to grow, both in the domestic and export markets." P&PC

Martin Koepenick, Innova International, Atlanta, GA, visits mills around the world, and has written about innovations in the pulp and paper industry for over 20 years.

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