Forming board

Base product produced as a granular loose fill, which can be bonded to form boards or dry mixed with fillers and binders for spray application. 

Extruded polystyrene board was first introduced in ihe early 1040s by Dow Chemical Co. with the tradename Styrofoam. The Styrofoam process consists of the extrusion of a mixture of polystyrene and volatile liquid blowing agent expanded through a die to form boards in various sizes. The conlinuous hoards are then passed through Ihe finishing equipment for further sizing. 

Chip makers dealing with waste wood produced about 1.8 million tons per year, and about 70 % of chips were for fuel and about 30% were recycled as a raw material in the paper and board industries (4). The amount of reuse of waste wood was very small compared with the generation. Particleboard or mat-formed board is a product that can use recycled wood (5) (6). Thus, the problems of recycled wood for board making was discussed in this paper. 

After the fibre mat is formed, it is typically prepressed in a band press. The densified mat is then trimmed by disc cutters and transferred to caul plates for the pressing operation. Dry-formed boards are pressed in multi-opening presses with temperatures of around... 

The fourdrinier wire (Fig. 6.38A) is the classical method of sheet formation. Speeds up to about 1200 m min are achieved with the fourdrinier. This is a reasonable limit due to excessive turbulence on the free suspension surface and dewatering capacity. Normally, the fourdrinier is equipped with a forming board, foils and/or table rolls, suction boxes, wet suction boxes, and suction rolls. Drainage proceeds in the direction of gravity. A dandy roll is often used just in front of the water line to improve formation. This is a wire-covered open roll, with a honey-... 

Sheet formation on an inclined wire section is performed in the area where the wire is covered by a box filled with the suspension and is usually under pressure (Fig. 6.38D). Here the wire is supported by some type of forming board. The pressure under the forming board can be controlled. This type of forming unit is for low machine speeds and operates with low consistencies of down to about 0.01 %. It is used for the production of special papers and nonwovens. 

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