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Fields of Strawboard

Manitoba is home to a new $140-million strawboard plant producing lsobord particleboard.

By John Dietz
Copyright 1998. Contact publisher for permission to use.

Forests are about as far removed as they can get in Manitoba's flatlands and fields, 30 miles west of downtown Winnipeg. But there's renewable fibre, and lots of it, in the straw residue from local wheat crops.

This past August, the production lines started up at Isobord Enterprises Inc., Manitoba's first strawboard plant. The $140-million facility is at Elie, Manitoba, adjacent to the TransCanada Highway and served by a CNR rail spur.

The plant is producing Isobord, a furniture-grade particleboard made from a unique combination of cereal straw and a resin called isocyanate, also know as NMI. With the initial success of this facility, Isobord Enterprises plans to establish additional operations in Western Canada and the United States.

Isobord Enterprises was founded in 1993 by company president Gary Gall and executive vice-president Steve Simon, with the purpose of establishing the first world-scale North American plant to manufacture industrial-grade, straw-based engineered composite panels.

Gall assisted in establishing the first waferboard plant in Timmins, Ontario, as well as the world's largest oriented strandboard (OSB) plant in Englehart, Ontario. He is an active consultant to the waferboard and OSB industries. Steve Simon's career has focussed on the use of agricultural residue in board production, particularly with Verkor BV, a Belgian company. Richard Duquette, the Isobord plant manager, initiated, supervised construction and brought into production the first MDF plant in Canada, at Whitecourt, Alberta.

Richard Duquette

Richard Duquette (above) Isobord plant manager, with Isobord particleboard produced from Manitoba straw. The board is manufactured with a resin binder, which becomes an inert compound with no toxic emissions.

Duquette, who is also vice-president and production for Isobord Enterprises, oversees daily operations at the 68-acre site.

A control room at the centre of the 215,000-square-foot facility contains sophisticated computer equipment which allows operators to control the entire manufacturing process. A total of only 70 people work in the control room and on the floor of the mill, which operates non-stop.

Manufacturing Plant

From its 215,000 square-foot plant in Elie, Manitoba, Isobord expects to produce 130 million square feet of product, enough to meet two per cent of the entire North American particleboard market.

The equipment used to make industrial panels from wheat straw is the same as any other very large, state-of-the-art computerized panel plant in the world, says Duquette, once the straw is hammered into fibre.

The first step in Isobord production is the chopping and refining of straw into fine particles. The particles are blended with resin, formed into a mat, then pressed to desired thicknesses and density. After cooling, trimming and sanding, the boards are packaged and sent into inventory storage to await shipping.

The technology for hammering straw bales into a multi-purpose fibre already existed. It was really the removal - by engineers and chemists - of the historical roadblocks of high resin content and long press cycles that cleared the way for construction of the strawboard plant, says Duquette.

The Manitoba facility is among the largest panel plants in the world, but in the perspective of the industry, it was simply built this big to achieve an economical scale for the components involved. It has one of the largest continuous presses in the world.

In spite of all this sophisticated equipment, however, the process still starts on the farm. About 350 farmers in a 50-mile radius have formed a co-op to supply wheat straw to the plant. In a two-month period after harvest, Isobord bales and delivers the annual supply of 400,000 large square bales of straw to one of three staging yards near the plant. Each bale measures 4'X4'X8' and weighs approximately 1,000 pounds. Moisture content of the straw is monitored and must be less than 20 per cent.

Approximately 50 bales an hour enter the plant when it is in full production. Operating non-stop, the line consumes approximately 1,100 bales every 24 hours.

"Handling those bales, off-loading, storage and getting them into the plant - it's all different," says Duquette. "You've got bulky material, wrapped in twine that has to be removed."

Isobord adopted bale-already being used in Denmark. Instead of burning straw in the field (a frequent practice on the prairies), the Danes bale the straw, transport it to power plants, where it is hammered and burned to produce electrical power. At Isobord's bale entrance, bales are unloaded onto a conveyor. From there on in, the equipment is controlled by computers to the far end of the production line, where forklift trucks move pallets of finished panels.

At the end of the conveyor, a bale wagon on rails accepts bales one at a time and delivers them to four bale-breaking lines inside the plant.

These lines, Duquette explains, cut the twine, remove it and move bales into breakers that loosen the straw. Four Sprout Matador hammer mills break down the straw to lengths less than 2". Bales can be fed into each of the four hammer mills at a rate of about 18" a minute.

The broken straw is carried upward pneumatically to a screening system where dirt, dust and fines are removed. Final drying occurs in two Kvaerner rotary triple-pass dryers located outside the plant. When the moisture content is down to three per cent, the straw pieces are ready for refining into particles in a process similar to other panel plants.

Isobord chose Pallman refiners, which are specifically designed to process straw, for this critical job. The refiners grind the long straw strands into particles with the proper geometry and distribution needed for the final product.

The particles are screened, separated into two sizes and moved into bins. The finest particles are used for panel surfaces; larger particles go into the core.

In his previous job with Alberta Energy Company in Edmonton, Duquette first considered making strawboard about 1995. At the time, he concluded it wasn't viable because resin content and consumption were too costly and press cycles were too slow.

"I became interested again when Isobord showed it was possible to reduce resin consumption and the press cycle," he said.

The Isobord product is made with a resin binder called Isobind isocyanate or MDI, manufactured by the Dow Chemical Company. After processing, MDI becomes an inert compound, with no toxic emissions.

MDI, also known as PMDI, is widely used in the OSB business, but it is new to particleboard. The industry standard, urea formaldehyde (UF), is used as a binder in about 90 per cent of the world's wood-based particleboard production, and in all wood-based particleboard plants in North America. Duquette says MDI is a safe, although expensive, alternative resin to UF. It also has much greater water resistance than UF. Combined with the natural water resistance in straw fibre, the new board is significantly improved.

Two blenders are used for mixing MDI with the core and surface particles. It is blended with the particles at a rate of four to five per cent. The two streams then move to a forming station in front of the press and are spread in layers, sandwiched between two sheets of kraft paper. Paper gives it the integrity to move through the press, while protecting the press from the resin, Duquette explains.

The continuous straw mat-8' wide and about 2" thick - is conveyed into the 130' Dieffenbacher press between two moving steel belts. Space between these top and bottom plates is reduced in a series of about 40 steps, gradually compressing the board. Heat and pressure are combined to produce a panel of specified thickness and density.

Beyond the press, an 8' sander removes the kraft paper, reduces board thickness to exact specifications and provides a smooth, uniform board face appropriate for paint, veneer or plastic laminate. The panels go into inventory after they are cut, stacked and wrapped. The plant will maintain an inventory of a million square feet or more of panel, in thicknesses up to 11/8".

As an industrial panel Isobord has no rain but does have an even texture that can be shaped. The product's texture is between particleboard and medium-density fiberboard (MDF). "It isn't MDF, but it is much better than particleboard," Duquette explains. "This is a texture between the two, so it will be very attractive."

The product has a surface equal to or better than the highest grade particleboard, thanks to the blending and forming process developed by Kvaerner Panel Systems GmbH (KPS). The process produces board with a very fine surface, a light, homogeneous core, and density of 40 lbs. per cubic foot, somewhat less than conventional wood-based particle-board. Its water absorption is lower than other particleboard or other MDF products, and it also has excellent machinability.

Based in Springe, Germany, KPS is a world leader in the manufacture of particleboard equipment. It has installed equipment in 700 particleboard plants worldwide, and the company invested 12 years of research in developing the non-toxic resin MDI as a replacement for UE Isobord and KPS jointly received a US patent for their new board-making process in 1996. A Canadian patent has also been recently granted.

Isobord recommends its product for the ready-to-assemble furniture market, kitchen cabinet makers, counter tops, shelving, as a substrate for laminated flooring and for hotel-restaurant-institution applications.

In lab testing compared to wood-based particleboard, Isobord has also demonstrated greater structural strength, greater fire resistance, more dimensional stability and better screw retention.

Duquette says approximately 80 per cent of product from the plant has been sold forward for the first five years of production, to leading makers of kitchen cabinets, counter tops and ready-to-assemble furniture. In full production, it's expected that the Manitoba plant will contribute approximately two per cent of North America's expanding demand for particleboard. Its capacity is rated at 130 million square feet (3/4" basis).

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