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Gypsum board

The PAPCEL group provides complete plants manufacturing gypsum boards. In the Angren Pack mill, a member of the PAPCEL group, the production of gypsum board was started up in the year of 2015. Angren Pack is a leader of the papermaking industry in Uzbekistan. It is the biggest producer of testliner TL3, RBF1, gypsum boards of basis weights 170 to 190 gsm, corrugated board and sanitary tissue.

Gypsum board properties

Gypsum board is popular for quick and easy mounting, lightness, strength, lifespan, flexibility, easy processing. The main raw materials used for gypsum board manufacture, i.e. gypsum and paperboard, give thermal and noise insulation. Price is another reason for its popularity. Waterproof gypsum board may be obtained adding waterproof foil. A gypsum board fire resistance is 30 minutes; the use of special coating increases the resistance up to 60 minutes.

Gypsum board usage

Gypsum board is a very flexible material with huge use opportunities. The basic gypsum board sorts are:
  • Common gypsum board - used for dividing walls and ceilings.
  • Standard gypsum board - suitable for walls in dry rooms with an ordinary air humidity.
  • Impregnated gypsum board - for rooms with air humidity of up to 75 %.
  • Fire-resistant and impregnated gypsum boards - suitable above all into lofts.

Concept of PAPCEL's stock preparation lines and approach flow systems

A stock preparation line (SPL) and an approach flow (AF) system must prepare stock that gives the manufactured product optimal values of all the wanted properties and at the same time a minimum energy consumption demand. Gypsum board can be manufactured in two or three layers, depending on the quality of the furnish raw material.

The standard furnish for gypsum board is 100% recycled paper consisting of various quality sorts. Different sorts are chosen for double- and triple-layer boards.

White wood-free waste paper (office waste) is used for the face of two-layer board  and OCC and OMP are used for the back layer.

Unprinted white wood-free paper is used for the three-layer board face, the same printed is used for the filler layer and OCC and/or OMP for the back layer.

Gypsum board machine

The gypsum board machine is utilised also to manufacture testliners for corrugated boards. Their design is thus very well-known and an important role is played by a multilayer wire part.

PAPCEL provides two- or three-wire machines working in the range of medium or high operation speeds.

Hydraulic headbox

Hydraulic headboxes with manifolds and dilution water automatic cross profile control is used most of all. 

Fig. Hydraulic headbox with manifold and dilution water automatic cross profile control


Wire part

Wire parts of gypsum BMs are composed of fourdrinier wires arranged to make two- or three-layer boards of the required quality. Just as for the other wire parts, the most important is the design of wire (dewatering) tables. The arrangement of the dewatering elements directly influences a burst strength or a ring crush test (RCT) value, together with a correct choice of a synthetic wire a wire retention and consequently an air permeability value are influenced. A Scott bond value indicating layer delamination is influenced by dryness on the boundary of the top and reverse/filer layers. Separate forming and dewatering enables to better utilise the potential fibre strength and thus to improve the manufactured board quality.

Press part

Gypsum boards and corrugated board layers require intensive pressing, i.e. using very high linear nip pressures, without a danger of crushing the paper web. Not surprisingly, the first jumbo presses (350 kN/m) were used just for this paper grade. Today, shoe press is a standard pressing technique for high dryness content entering the dryer section.

Drying part

For medium or high speeds the first or several follow-up dryer sections are of the Uni-Run or single-tier type. The bottom dryer line is composed of cylinders under vacuum. The number of the cylinders depends on a machine speed and on a manufactured paper basis weight. The main aim of such arrangement is a permanent contact of paper with the drying fabrics preventing paper breaks. The following dryer sections are of a common type with a double-tier arrangement of dryers.

Size and film press

Size or film presses are integral parts of all the gypsum board machines. Using the former or the latter one depends on a BM operation speed and on a customer's wish coming from a previous experience. However, the general rule is that the size presses are used for medium speeds while the film presses for higher speeds.

Calender

Calendering is a manufacturing operation giving paper a required smoothness and a uniform thickness.

The calender is usually a single nip calender, its smooth, heated roll of a large diameter is in top position while the smaller roll with a controlled profile is in the bottom position. The linear nip pressure is up to 300 kN/m.

Reel

A reel, in most cases a hydraulic one, winds paper web onto reels of any diameter limited only by a machine design arrangement. Reels are wound continuously on exchangeable reel spools used also for follow-up rewinding the reels.

Winder with tangential slitting section

The gypsum board manufacturing lines are ended, similarly to other PMs with two-drum winders. The winders rewind reels from reel spools to rolls of required widths and diameters on cores. The roll dimensions, winding toughness and side cut perpendicularity are set on the winders. The finished rolls are ready for shipping. The converter's requirements for the mentioned parameters influenced by the winders are very demanding. The rolls must be wound without breaks not to limit gypsum board converting lines capacities.