Paper making and fiber liberation – Processes and products – Non-fiber additive
Patent
1994-10-31
1997-09-23
Czaja, Donald E.
Paper making and fiber liberation
Processes and products
Non-fiber additive
1621643, 1621687, 1621817, 162183, D21H 2110, D21H 1714
Patent
active
056700210
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to papermaking, particularly to a method whereby a suspension of pulp, containing optional filler and cationic starch, is spread over a wire or cloth and the water is removed to form a fibre web or sheet. More particularly the invention relates to the use of a special combination of phenolic resin, alkali metal silicate and polyethylene oxide, with the above-mentioned paper furnish components. The purpose of this special combination which is described in this invention is to provide a flocculation process leading to improved retention of fines in the paper sheet, improved drainage and drying properties and consequent increases in recovery and production rate whilst also maintaining good sheet quality.
BACKGROUND AND SUMMARY OF INVENTION
The prior art contains many examples of chemical systems to improve retention and drainage in the production of paper and paperboard. These systems include the combination of phenolic resin and polyethylene oxide which has been particularly successful for newsprint applications, where mechanical pulp containing dissolved organic contaminants causes detrimental effects to other retention treatments. Phenolic resin is usually added first, before the last shear zone, such as a fan pump, and polyethylene oxide is added second, usually near the headbox in order to minimise shear. It has been proposed that the mechanism of this two-component systems consists firstly of adsorption of the phenolic resin onto fibres and fines, followed by attachment of polyethylene oxide to the phenolic hydroxyl groups of the resin, forming high molecular weight polymeric networks which serve to retain the fines and also promote drainage.
The above system is independent of most dissolved and colloidal contaminants in the water circuit because it functions by a hydrogen-bonding mechanism. In contrast, commonly-used cationic polyacrylamides are adversely affected by many dissolved and colloidal organic contaminants in mechanical pulp from species such as Radiata pine used in many newsprint mills. Consequently, the phenolic resin/polyethylene oxide system has been adopted in many newsprint mills in recent years. This system has several other advantages including more favourable effects on the final sheet formation than some other retention systems. It has also been demonstrated that fillers such as kaolin can actually assist the overall retention and drainage if they are premixed with the phenolic resin prior to addition to the stock, and then the polyethylene oxide is added. Another advantage of the phenolic resin/polyethylene oxide combination is pitch control which refers to its ability to fix organic contaminants in the paper sheet rather than allowing them to deposit on the mill fabrics and machinery and cause eventual shutdowns.
Nevertheless, despite the above advantages, this retention and drainage system has not been adopted in other mills producing grades such as fine paper, tissue and packaging papers, where mechanical pulp from softwood does not form a large part of the furnish. In these areas, cationic polyacrylamides are the predominant treatment. There are also some recent two component processes, including the combination of cationic polymer and bentonite (AU-B-68118/87) and the combination of cationic polymer and colloidal silica or modified polysilicic acid, as described scribed in AU-B-34970/89, AU-B-37345/89 and AU-B-41363/89.
The main reason for the lack of success of the phenolic resin/polyethylene oxide system in the above areas is the reduced performance owing to the lack of organic contaminants in these furnishes compared to the softwood mechanical pulp used in many newsprint applications. These contaminants provide a part of the network mechanism by which this retention system functions and their absence in other furnishes such as sulphate pulp and recycled and deinked pulp has led to the predominance of other retention systems, especially cationic polyacrylamides. In addition it has been found that residual silicate in t
REFERENCES:
patent: 4070236 (1978-01-01), Carrard et al.
patent: 4313790 (1982-02-01), Pelton et al.
patent: 4927498 (1990-05-01), Rushmere
patent: 4954220 (1990-09-01), Rushmere
patent: 5098520 (1992-03-01), Begala
patent: 5173208 (1992-12-01), Chung et al.
Leung et al. "Flocculation of paper fines by polyethyleneoxide", Tappi Journal, vol. 70, No. 7, pp. 115-118 Jul. 1987.
Pelton et al., "Novel dual-polymer retention aids for newsprint and groundwood specialties", Tappi Journal, vol. 64, No. 11, pp. 89-92 Nov. 1981.
Braun et al., "Filler and fiber retention in newsprint and groundwood specialties using poly(ethylen-oxide)", Tappi Journal, vol. 67, No. 9, pp. 110-114.
Tay, "Appliction of polymeric flocculant in newsprint stock system for fines retention improvement", Tappi Journal, vol. 63, No. 6, pp. 63-66 Jun. 1980.
Wegner, "The effects of polymeric additive on papermaking", Tappi Journal, vol. 70, No. 7, pp. 107-111 Jul. 1987.
Pelton, et al., "A survey of potential retention aids for newsprint manufacture", Pulp & Paper, vol. 81, No. 1, pp. 54-62 Jan. 1980.
Czaja Donald E.
Fortuna Jos'e A.
Kemira Kemi Aktiebolag
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