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Article | August 31, 1996
IP revs up recycled linerboard machine
International Paper enters the recycled linerboard manufacturing market with what it touts as "the world's largest recycled linerboard machine." The machine produces up to 1겨 tons/day at IP's Mansfield, LA, mill. Box makers respond positively.
Satisfied customers Tanner says customers "have responded positively to the sheet we produce on the Valmet." Wichita KS-based Love Box Co. is a good example. A 40-year IP customer Love Box manufactures corrugated boxes used as shipping cases by food and industrial goods packagers. The company produces single-face single- and double-wall boxes in A B C E and F flutes. "We've ordered material from the new machine since its startup" says Robert Love vice president. "Before installing the machine they didn't have 100-percent recycled board capacity at the mills that were supplying us. This is their first venture into supplying our market with high-performance lightweight recycled board in the 35-pound mottled white and kraft varieties that we use regularly." Love says "We have access to a number of good board suppliers but we receive excellent value in terms of stacking strength and board performance from the sheet produced on the new machine at Mansfield. IP's processing of the linerboard's long and short fibers provides especially good ring crush test numbers and that's a key specification we look at in buying board." Before the new machine was running at Mansfield Love Box purchased virgin 35# linerboard from IP. "There were numerous factors that prompted our use of recycled sheet" says Love. Much of it had to do with upstream board manufacturing costs that were eventually passed along to Love Box. "Costs for the wood chips used in virgin board manufacture became higher especially on the west coast where there were lumber cutting restrictions. Recycled versus virgin board pricing varies depending on capacity at the mills that supply us" he notes. "Their raw materials cost determines production volumes of virgin or recycled" Love explains. "Recycled materials can be less expensive but if the demand for secondary recycled fiber goes up those costs would rise. Today we're probably pressing the limits of our ability to run recycled materials on a worldwide basis and we'll see the day when virgin linerboard mills will have to be brought onstream to add capacity. Then virgin will be more economical." Environmental concern wasn't a major reason for Love Box's use of recycled-content board however. "There was a time when the environment was a strong selling point for all of us. That has dwindled somewhat. We're still environmentally conscious though we view it as more of a responsibility than a marketing advantage in that it's better to reuse OCCs than landfill them which can be expensive" says Love. The bottom line then he says "is that with recycled board we have an alternative choice that's comparable in performance. It gives us a more flexible supply." Quality control At Mansfield the new machine is referred to as PM3 or Paper Machine #3. The mill's two original machines have a combined capacity of about 1 million tons/yr. PM1 produces heavier-grade board in 42# to 96# basis weights; PM2 manufactures 26# to 40# semi-chemical medium sheet stock. PM3 serves both IP boxmaking facilities and outside customers. Sales are divided roughly 50:50 between the two. For PM3 raw materials Mansfield uses a network of brokers as well as local municipalities and stores to acquire old corrugated containers (OCC). "When we began to purchase and warehouse materials in preparation of starting up the new machine we implemented tight specifications to make sure we were receiving the level of quality we wanted" recalls Gerald Robertson project manager for the installation of PM3. "We not only trained our receiving personnel on how to inspect the incoming bales of OCC but we also communicated our needs to our suppliers. Early on we rejected a number of deliveries making it clear what we needed in terms of quality and consistency" he points out. Maintaining quality was particularly important at that time Robertson notes "because as everyone in our business knows prices had rocketed pretty high. We paid in the neighborhood of $200 a ton for those recycled materials. That's down substantially today." (Also see Enviro-scope on page 50.) Fourdrinier-on-fourdrinier Up to 1 tons of recycled material can be held within a fiber storage chest at Mansfield. Fiber is moved into two headboxes one for a top fourdrinier a second for the base fourdrinier. (A fourdrinier is a machine where the board is formed.) Top and bottom mats are formed then pressed together into a single sheet to form the board. The concept differs from most linerboard-making processes that use a simpler single-sheet approach. The PM3's use of two fourdriniers referred to by Valmet and IP as the fourdrinier-on-fourdrinier concept gives Mansfield the ability to control formation of both mats which is important not only for strength but also for printability. "The fourdrinier-on-fourdrinier concept allows the use of more sophisticated technology in forming the sheet" says Robertson. "You're able to control the cross-directional formation of the fibers before you put the mats together to form the sheet." In each of the headboxes the recycled material mixes with water to form a slurry. Pressure in both the top and base headboxes is closely controlled as is agitation of the slurry within a moving fabric or wire section. In this section extensive vacuum is used to partially dewater the slurry. Angled foil blades also help make uniform fiber mats. At this point both base and top mats comprise 85% water. The top mat is then delivered down to the base mat to form a single sheet. Pressing and sizing The sheet enters a press section where additional water is mechanically squeezed out by the pressing of the sheet within two sequential press nips. Pressing out excess water reduces downstream drying costs and helps to improve strength and sheet smoothness. The pressed sheet conveys through a series of dryers to further remove moisture. About two-thirds of the way through drying the sheet moves through an inclined size press where a starch solution can be applied to the top and bottom of the sheet. This solution is designed to improve sheet strength and smoothness. Next the sheet passes through a set of rollers (a calender) where heat pressure and time help create a sheet with uniform moisture thickness and printability characteristics. Ahead of forecast The 350"-wide sheet is then wound into a 40-ton reel that's slit into five or six "sets." Each is then further slit into individual rolls whose widths are specified by customers. Rolls are weighed banded and labeled with handling instructions. Mansfield ships by rail and truck with some customers making direct pickups. IP gives the thumbs-up sign to the Valmet machine's first 10 months of operation at the Mansfield mill. "We are still within about a two-year ramp-up period that we anticipated with the PM3" Tanner summarizes. "But at this point production is considerably ahead of our initial forecast."
International Paper jumped into recycled linerboard manufacturing in a big way last December with the start-up of a $350 million machine that produces up to 1 tons/day at its Mansfield LA mill. Made by Valmet (Charlotte NC) the equipment uses 100% recycled material to produce lightweight board in 26# to 47# basis weights in white-top and kraft varieties. It is capable of producing recycled/virgin blends as well. "There were three different issues that led us to installing this equipment" states Hal Tanner manager of packaging services for IP's Containerboard and Kraft Division. "One we did not previously have recycled linerboard production capability. "Two we recognized that one of the fastest-growing board markets is for white liners that offer visual appeal" he adds. "Now we have the capacity to produce solid bleached white and white-top linerboard. "Three we needed to strengthen our capacity in the high-performance lighter-weightboard grades between 26 and 42 pounds." The Valmet machine "has given us a strong presence in these important market areas" says Tanner. Though IP wouldn't provide expected payback or sales figures it's apparent that the Purchase NY-based firm is satisfied with the machine thus far. "We significantly improved our position as a supplier of premium-grade containerboard with the start-up of the machine" notes the company's 1995 Annual Report. Customers also benefit. "The machine uses the latest technology in recycled fiber cleaning so it produces board with a much better appearance than many recycled grades" Tanner says. "The formation of fibers across the sheet is uniform with no clumps. That results in good ring crush and compression strength. We regularly test linerboard to make sure we're supplying a high-performance sheet that runs well on customers' corrugating equipment. "There is also uniform moisture" he adds. "That's important because it eliminates moisture streaks which can cause warping during box forming. Streaking can also make it more difficult for converters to bond corrugated during box manufacturing."
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