Eka Nobel Ab

Eka Chemicals Ab

Eka Aktiebolag

Elektrokemiska Aktiebolaget

Hans E Johansson

Bo V Larsson

Michael Persson

Hans M Larsson

Per J Svending

Per G Batelson

Carlos Cordoba

Joakim Carlen

Erik Lindgren

Marek T Tokarz

Kjell Rune Andersson

Olof Sunden

Kjell Johansson

Kjell R Andersson

Stefan Klofver

Zaid Schold

Ake Larsson

Tomas Lund

Per-Arne I Karlsson

Hakan B Ahlberg

The invention relates to a process for the production of paper from a suspension of cellulose containing fibers, and optional fillers, comprising adding to the suspension a low molecular weight cationic organic polymer, a high molecular weight cationic or amphoteric polymer and anionic inorganic particles, forming and draining the suspension on a wire, wherein the low molecular weight polymer has a molecular weight below 700,000 and the high molecular weight polymer has a molecular weight above 1,000,000, said polymers being simultaneously added to the suspension. The invention further relates to a polymer mixture in the form of an aqueous dispersion comprising at least one high molecular weight cationic or amphoteric acrylamide-based polymer having a molecular weight above 1,000,000, at least one low molecular weight cationic organic polymer having a molecular weight below 700,000 and at least one water-soluble inorganic salt, the weight ratio of said high molecular weight polymer to said low molecular weight polymer being within the range of from 9:1 to 1:2.

Process for the production of paper

Sizing dispersions

A process for the production of paper from a suspension of cellulose containing fibers, and optional fillers, which comprises adding an aluminum compound and anionic inorganic particles to the suspension, forming and draining the suspension on a wire, wherein the aluminum compound and anionic inorganic particles are mixed immediately prior to addition to the suspension.

The invention generally relates to a process for modification of cationic starch at which the cationic starch is treated, in the presence of water, with an aluminium compound. The modified cationic starch is useful as a retention agent. The invention also relates to a method for improving retention and/or dewatering in papermaking at which cationic starch is modified by the process.

Modificaton of starch

In the evaporation of process wastewater comprising a mixture of different types of wastewater, problems arise due to the formation of reaction products, so-called incrustations, which are difficult to separate. These incrustations clog up the evaporator, thus necessitating frequent stoppages for chemical and mechanical cleaning of the evaporator. The invention concerns an improved method for concentrating process wastewater by evaporation. In this method, one acid process flow and one alkaline process flow are evaporated alternately in one and the same evaporator. With this method, precipitates that are difficult to separate are dissolved in the evaporator during the respective evaporations. As a result, stoppages motivated by the need to clean the evaporator may be avoided to the utmost possible extent, while less and cheaper processing equipment is required.

Method for evaporating process wastewater

Silica sols having a high content of microgel and aluminum modified particles with high specific surface area. The sols can be prepared by a process comprising acidification of a water glass solution, alkalization at a certain dry substance content, particle growth and aluminum modification. The sols are particularly suitable for use as additives, in combination with cationic polymers, in papermaking.

Silica sols in papermaking

Aqueous suspensions of colloidal particles, preparation and use of the

Silica sols, a process for the production of silica sols and use of the

Silica sols having high surface area

Cellulose fibre containing products in sheet or web form, such as paper and pulp sheets, are produced from a suspension of cellulose containing fibres, and optional fillers, to which is added anionic inorganic particles, such as bentonite and silica based particles, and a cationic carbohydrate polymer containing aluminum. The cationic carbohydrate polymers are cationic galactomannans or cationic starch. High cationized starch with a degree of substitution of at least 0.07 are especially suitable.

Process for the production of cellulose fibre containing products in

A process for the production of paper by forming and dewatering a suspension of cellulose containing fibres, and optional fillers, on a wire. The forming and dewatering is carried out in the presence of a combination of an aluminum compound, a cationic retention agent and a polymeric silicic acid having a high specific surface area. The combination of substances improves dewatering and retention of fines and fillers.

In making paper from an aqueous papermaking stock a binder comprising colloidal silicic acid and cationic starch is added to the stock for improving the paper or the retention of the stock components, or is added to the white water for reducing the pollution problems or recovering values from the white water. The cationic starch of the binder has a degree of substitution of not less than 0.01, and the weight ratio of cationic starch to SiO.sub.2 is between 1:1 and 25:1.

Papermaking and products made thereby

A papermaking process in which an aqueous papermaking stock containing a cellulosic pulp is formed and dried. The stock includes a binder comprising colloidal silicic acid, and cationic starch which is added to the stock before the sheet is formed. The manner of addition involves first adding and intermixing in the stock a portion of the colloidal silicic acid and then the cationic starch and, after an agglomerate has formed, adding and intermixing the remainder of the colloidal silicic acid prior to the formation of the sheet. The method results in improved sheet properties and improved retention of filler and fines on the wire.

Growing community of inventors

Kungalv, Sweden

Hans E Johansson