Patent GB-543862-A (GB)
Title: Improvements in or relating to a process of treating cellulosic fibres for paper making and the treated cellulosic fibres and paper produced therefrom
IPC: D21C1/00
Filed: 1940-06-06
Abstract: 543,862. Production of cellulose pulp and paper..FOWLER, G. B. June 6, 1940, Nos. 9941 and 9942. Convention dates, Feb. 13 and April 22. [Class 2 (ii)]' Cellulosic fibres are rendered suitable for paper-making by immersing or soaking them at room temperature in a dilute solution or dispersion of an organic wetting agent having a swelling action on them; and then digesting or cooking the swollen fibres in a solution of a pulping agent. The preliminary treatment facilitates the removal of the non-cellulosic constituents. Cellulose of high viscosity characteristics and of a low copper number may be obtained. The ratio of the cuprammonium viscosity of the cellulose to the copper number may be greater than 3,000 to 1. The raw material may be cotton, ramie, sisal, hemp, flax, jute and caroa. The process may be used in' the production of paper stock from which high-grade paper such as writing-paper, ledger, bond, or onion-skin paper may be obtained. The fibres may be digested or cooked with caustic soda, lime, sodium carbonate, sodium sulphide, or bisulphite. The wetting agent may be a long chain alcohol sulphate, e.g. Gardinol or Duponol LS, or sodium abietene sulphonate, e.g. Neopen SS, or a higher secondary alcohol sulphate, e.g. Tergitol Penetrant, or a substance known under the Registered Trade Mark " Triton " particularly " Triton W 30." It may be an octyl phenol, a condensation product of di-isobutylene and phenols, or an α.α.γ.γ. tetramethyl butyl phenol, a condensation product of an alcohol with a phenol, a naphthalene-isobutylene polymer sulphonate, or a tert. alkylaryl-oxy alkylol. In an example, cotton linters is placed in a boiler and water containing a wetting agent is added. The boiler is rotated at room temperature for two hours at the end of which time most of the water has become absorbed in the fibres which are uniformly wet and swollen to a great extent. Further water is added and also flake caustic soda. The boiler is sealed and rotated while being heated by direct steam under pressure for several hours. The pressure is released and after cooling slightly, the cooked fibres are discharged into a beater which is provided with a lava stone bed plate and with a washing cylinder covered with a fine mesh wire. The fibres are washed for a few hours with the beater roll adjusted to the brushing position. Hypochlorite solution and aluminium sulphate are then added. At the end of the bleaching operation the washer cylinder is lowered into the stock and the excess of bleaching liquor is removed. After further washing, an antichlor is added, and then a filler such as a titanium pigment, and a size such as a rosin size and aluminium sulphate is added. Gelated starch is also added and the starch is subsequently precipitated on the fibres by means of sodium aluminate. The beating is' continued for a few hours and the stock is then transferred to a Jordan chest, passed through the Jordan, and on to the machine chest. Instead of cotton linters there may be used raw cotton or other cellulosic fibres and textile wastes.