Other

Eka Ab

Rune G Simonson

Goran Bengtsson

Roland Agnemo

Brita Ohlsson

Birgit Stman

Per O Axelson

Knut Lundquist

A method for the manufacture of products containing fibers of lignocellulosic material which involves the disintegration of a lignocellulosic material into fibers and forming and pressing of the fiber web into the product in question, which is preferably in the form of fiberboard (board products). The material that forms the fibers is impregnated with lignin in conjunction with water and at a pH which does not substantially exceed 12.5. When the lignin has been absorbed by the material it is fixed against leaching by water through the modification of said lignin into an essentially water-insoluble form.

Method for the manufacture of products containing fibers of

Chemimechanical pulp is produced from lignocellulosic material in a process in which the material is impregnated in two stages. The material is treated in the first stage with alkaline and, subsequent to passing an intermediate draining and reaction step, in the second stage with a solution that contains peroxide. The quantities of alkali and peroxide charged are fully optional and are independent of one another. The material is then optionally subjected to a further drainage and reaction step, and thereafter pre-heated at a temperature of between 50.degree. C. and 100.degree. C., whereafter the material is refined in one or two stages. The optimal brightness of the processed pulp for a given peroxide consumption is achieved by a balanced division of the peroxide charge between chip impregnation and bleaching.

Method of manufacturing bleached chemi-mechanical and semichemical fibre

A method for the manufacture of products containing compressed and adhesive-bonded wood chippings, preferably of different sizes. Before the chippings are combined together by glueing to form a product of high dimensional stability, they are impregnated with lignin in conjunction with water and at a pH which essentially does not exceed 12.5. Once the lignin has been absorbed by the wood chippings it is fixed against leaching by the water by the modification of same into an essentially water-insoluble form by impregnating the chips with a weakly acid aqueous solution of a metal salt.

Method for the manufacture of products containing wood chips by

A method for the production of fiber pulp from lignocellulosic material containing at least 70% spruce or spruce-like material. The method comprises the steps of lignin softening and defibration/refining, the step of lignin softening being performed prior to the step of defibration/refining and comprising impregnating the starting material with a dilute aqueous solution of a lignin softening agent, namely a solution of sulfurous acid, metal bisulfite salts and/or metal sulfite salts in an amount sufficient to provide a defibrated/refined pulp containing an absorbed and bonded amount of sulfonate groups within the range of from 0.06 to 0.75 wt.-%, calculated as Na.sub.2 SO.sub.3 and based on the dry pulp weight. The absorbed and bonded amount of sulfonate groups is balanced to the composition of the starting material and the temperature-pressure conditions in the defibration step to provide a pulp of maximum tensile strength such as to represent a point within the polygon ABGH in FIG. 1. The invention makes it possible to utilize favorable effects, not earlier known, resulting from very low concentrations of the lignin softening agent, and to produce a pulp with high yield and optimum strength and optical properties at a comparatively low energy input in the defibrator/refiner.

Method for the production of fiber pulp by impregnating lignocellulosic

In accordance with the invention a chemimechanical pulp is produced from lignocellulosic material, for example wood chips, by subjecting the material to a process in which it is steamed, impregnated with alkali and peroxide, drained, pre-heated, refined and bleached. The material is impregnated in a single stage with a solution containing alkali and peroxide. Subsequent to passing an intermediate drainage and reaction stage, the material is pre-heated to a temperature of from about 50.degree. C., but not above 100.degree. C. The material is then refined in one or two stages. The material can be impregnated by immersing the same in the impregnating solution for a period of up to 20 minutes at a temperature of 15.degree.-60.degree. C., or by compressing the material in a screw press and permitting the compressed material to expand in the impregnating solution. The optimal brightness for a given peroxide charge is achieved by a balanced division of the peroxide charge between the chip impregnating stage and the bleaching stage.

Method of manufacturing bleached chemimechanical and semichemical fibre

A method for the impregnation of wood to prevent attack by harmful agents such as decay fungi or mould fungi and bacteria by the application of an aqueous solution of an alkali lignin modified into a water-soluble form. Impregnation takes place in two stages, these being an initial stage in which the aqueous solution containing the lignin still in its water-soluble form and with a pH not exceeding 10 is applied to the timber, and a second stage in which the lignin is fixed as a water-insoluble form by the application to the timber of a weakly acidic aqueous solution containing metal ions by the addition of metal salt.

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Partille, Sweden

Rune G Simonson