Abstract: A new class of polymeric additives for papermaking is disclosed as well as a process for their manufacture, a method for their use and a paper sheet containing the addition. The additives can be used in paper manufacture as agents for improving retention, paper machine operation and the strength properties of the product. The additives are manufactured from a microbial biomass. The biomass that contains acetyl amino groups or other amides is chemically modified by hydrolysis of the amides to form primary amino groups. Under neutral or acidic conditions these primary amines become cationic, which assures a good absorption of the additive onto fibres and fines of pulp that is generally of anionic nature.

Abstract: Disclosed is a method for manufacture and application of a polymeric papermaking additive, which can be used in paper manufacture as an agent for improving retention, drainage, product strength and paper machine operation. The additive according to this disclosure is a polymer of epichlorohydrin and contains primary amino groups. Under neutral or acidic conditions these primary amino groups become cationic, which assures good adsorption of the polymer onto anionic fibers and fines of pulps used for production of paper or paperboard. By adsorbing on several fibers or fines, the polymer can increase the retention of fines and fillers. Primary amino groups of this polymer can also form chemical bonds with carbonyl groups of cellulose, lignin and hemicellulose, which are especially abundant in the fibers and fines of mechanical pulps. The cross-linking of fibers and fines by chemical bonds can increase the initial strength of wet web and the strength of rewetted paper.

Abstract: A novel method for the production of light-stable and process-stable lignocellulosic materials, in particular, the production of mechanical wood pulps with much improved light and process stability is described, as well as the resulting pulps of improved light and process stability and papers containing such pulps. The novel method involves the reaction of lignocellulosic materials such as bleached chemithermomechanical pulps (BCTMP) with (a) a water-soluble, fibre-reactive yellowing inhibitor possessing two or more secondary amino or ammonium (—NHR? or —HN+HR?), tertiary amino or ammonium (—NR?R? or —HN+R?R?), and/or quaternary ammonium (—N+R?R?R??) functional groups in an aqueous medium, or (b) a water-soluble, fibre-reactive hindered amine light stabilizer possessing said amino or ammonium functional groups in an alkaline peroxide bleaching medium or in an aqueous medium with a subsequent bleaching of the materials in an alkaline peroxide bleaching medium.

Abstract: The invention relates to an apparatus for detecting plugged sites and holes and for measuring of the water permeability properties of pervious machine fabrics. Plugged sites in a permeable fabric are detected by sensing water pressure pulses occurring in the nozzle at the moment when a stream of water flowing through the nozzle contacts a plugged site on a fast running fabric. The apparatus can be used on-line to simultaneously detect plugged sites and holes on a moving pervious fabric while monitoring its water permeability properties.

Abstract: A transfer system for transferring a moving wet cellulosic web between two moving elements of a paper machine without excessive sheet flutter or breakage, supports the web and permits higher web speeds than presently used. The transfer system comprises a suction roll that forms a nip in contact with the web on the surface of a roll or web supporting belt, a doctor blade positioned in contact with the surface of the roll or web supporting belt immediately after the nip to ensure the web separates from the surface, and an air jet adjacent the doctor blade that blows air in a direction substantially opposite the moving web, between the moving web and the surface of the roll or web supporting belt, to guide and support the web towards the suction roll.

Abstract: A method and a machine are described for drying of fibrous web, especially suitable for high speed machines producing printing papers. High drying rates are obtained by subsequently pressing the two surfaces of wet web onto two large diameter dryer cylinders heated to between 100.degree. and 150.degree. C. In the first nip, the web is pressed on the dryer cylinder by a felted press roll, while and unfelted smooth roll is used to press the web on the second dryer. Drying rates obtained when practicing the invention are substantially greater than those found in conventional dryer sections. The product obtained according to this method is 30% stronger than the conventionally dried uncalendered paper, and without calendering has a smoothness and gloss similar to those of calendered conventional papers.

Abstract: A method for measuring the permeability of pervious sheet material is disclosed; the measurement is based on the flow rate of water ejected at a given pressure between 2 and 1000 kPa through a nozzle pressed against one surface of the sheet material whose permeability is to be measured.