Abstract: A dewatering device has a dewatering box and a plurality of dewatering strips. A contour of at least one dewatering strip changes over its length. There is also described a machine for the production of a fibrous web, such as a paper, cardboard or tissue web, with a dewatering device of this kind, and to the use of the latter in a machine of this kind.

Abstract: A dewatering device has a dewatering box and a plurality of dewatering strips. A contour of at least one dewatering strip changes over its length. There is also described a machine for the production of a fibrous web, such as a paper, cardboard or tissue web, with a dewatering device of this kind, and to the use of the latter in a machine of this kind.

Abstract: A method of operating a machine for producing a fibrous web. The machine has a de-watering device with a plurality of pivotally embodied de-watering strips. In the method, an inclination angle of at least one of the de-watering strips is modified as a function of at least one parameter. The modification is effected by way of the pivoting installation which is activated by a control installation. The actual inclination angle of the at least one de-watering strip to be pivoted is detected and transmitted to the control installation. The control installation activates the pivoting installation as a function of the transmitted inclination angle.

Abstract: A method of operating a machine for producing a fibrous web. The machine has a de-watering device with a plurality of pivotally embodied de-watering strips. In the method, an inclination angle of at least one of the de-watering strips is modified as a function of at least one parameter. The modification is effected by way of the pivoting installation which is activated by a control installation. The actual inclination angle of the at least one de-watering strip to be pivoted is detected and transmitted to the control installation. The control installation activates the pivoting installation as a function of the transmitted inclination angle.

Abstract: Disclosed is a method for producing a fibrous web, in particular a paper web, paperboard web or tissue web, with which a material flow of higher consistency and a material flow of lower consistency are mixed in a variable ratio over the machine width and the mixed flow is fed via a headbox as a headbox stream to a mesh section, whereby the mixing ratio between these two material flows of different consistency in the respective mixed flow acts as the set-point variable for controlling the gsm substance of the fibrous web over the machine width. In this case the ratio between the fibrous material content and the filler material content in the material flow of lower consistency is established or controlled such that the filler material fraction in the fibrous web can be established or controlled at least essentially independently of the gsm substance.

Abstract: The present invention relates to a method and a corresponding plant for producing a fibrous web, in particular a paper web, paperboard web or tissue web. The formation of the fibrous web is defined online as a controlled variable and is held at a preselectable set-point level by way of an automatic formation control system.

Abstract: Disclosed is a method for producing a fibrous web, in particular a paper web, paperboard web or tissue web, with which a material flow of higher consistency and a material flow of lower consistency are mixed in a variable ratio over the machine width and the mixed flow is fed via a headbox as a headbox stream to a mesh section, whereby the mixing ratio between these two material flows of different consistency in the respective mixed flow acts as the set-point variable for controlling the gsm substance of the fibrous web over the machine width. In this case the ratio between the fibrous material content and the filler material content in the material flow of lower consistency is established or controlled such that the filler material fraction in the fibrous web can be established or controlled at least essentially independently of the gsm substance.

Abstract: The present invention relates to a polysaccharide having functional groups, wherein said groups are aldehyde groups formed at positions C2 and/or C3 as well as at position C6 of the anhydroglucose units of the polysaccharide chain. Preferably the polysaccharide is a cellulosic fibrous material whose primary and secondary hydroxyl groups of the cellulose are oxidized into aldehyde groups at least in part by means of TEMPO oxidation and periodate oxidation. The invention also concerns a paper or nonwoven comprising the above polysacaride. According to the invention a relative wet strength of more than 10% can be achieved.

Abstract: A process for producing nitrosonium ions is described, in which a nitroxyl compound such as TEMPO is oxidized using an oxidizing agent in the presence of a complex of a transition metal such as Mn, Fe, Cu, and a complexing agent such as a polyamine. The process is useful for the oxidation of carbohydrates containing at least 1 cyclic monosaccharide chain group carrying a carbaldehyde group per 100 or per 25 monosaccharide units and per molecule.

Abstract: The present invention relates to a cellulose-containing fibrous material, wherein hydroxy groups were oxidized at the C(6) of glucose units of the cellulose into aldehyde and/or carboxy groups, a paper or nonwoven (product) made therefrom, in particular tissue (products) and a process for their manufacture. The paper or nonwoven (products) of the invention display excellent strength properties.

Abstract: In a new process for oxidizing a primary and/or secondary alcohol, an oxidizing agent is used in the presence of a di-tertiary-alkyl nitroxyl, in an aqueous reaction medium at a pH of below 7. The di-tertiary-alkyl nitroxyl is especially 4-hydroxy-TEMPO, and the process is particularly advantageous for oxidizing carbohydrates such as starch.

Abstract: The present invention relates to a polysaccharide having functional groups, wherein said groups are aldehyde groups formed at positions C2 and/or C3 as well as at position C6 of the anhydroglucose units of the polysaccharide chain. Preferably the polysaccharide is a cellulosic fibrous material whose primary and secondary hydroxyl groups of the cellulose are oxidized into aldehyde groups at least in part by means of TEMPO oxidation and periodate oxidation.

Abstract: The present invention relates to a polysaccharide having functional groups, wherein said groups are aldehyde groups formed at positions C2 and/or C3 as well as at position C6 of the anhydroglucose units of the polysaccharide chain. Preferably the polysaccharide is a cellulosic fibrous material whose primary and secondary hydroxyl groups of the cellulose are oxidized into aldehyde groups at least in part by means of TEMPO oxidation and periodate oxidation. The invention also concerns a paper or nonwoven comprising the above polysaccharide. According to the invention a relative wet strength of more than 10% can be achieved.

Abstract: A treatment sequence includes ozonation under acidic conditions followed by an acidic wash for enhancing the wet strength of a cellulosic fibrous material. Preferably the ozone treatment and the acidic wash are followed by a second ozonation step under acidic conditions. The fibrous cellulosic material obtained by this treatment sequence has a breaking length of at least 100 m. The wet strength of the cellulosic fibrous material is increased without the use of additives, such as wet strength agents. This use of ozone is very simple and efficient, and leads to highly pure products. The use of ozone as the only treatment chemical in particular avoids the introduction of so-called “non-process elements” (NPE) into the treatment system, for instance metal oxides such as MgO, which are frequently used in the oxidative treatment of pulps.

Abstract: The present invention relates to a cellulose-containing fibrous material, wherein hydroxy groups were oxidized at the C(6) of glucose units of the cellulose into aldehyde and/or carboxy groups, a paper or nonwoven (product) made therefrom, in particular tissue (products) a process for their manufacture. The paper or nonwoven (products) of the invention display excellent strength properties.

Abstract: The present invention relates to crosslinked cellulose-containing fibrous material, wherein hydroxy groups are oxidized at the C(6) of glucose units of the cellulose into aldehyde and/or carboxy groups crosslinked with a metal-containing crosslinking agent selected from transition metals of groups of IVa (preferably Zr), Va, VIa, VIIa and VIIIa, aluminum and zinc; and a paper or nonwoven (product), e.g. tissue (product), which comprises this fibrous material. These paper or nonwoven (products) are distinguished by high wet and dry strength.

Abstract: A method of bleaching lignocellulosic fibers is disclosed which comprises the step of treating the lignocellulosic fibers with a bleaching composition comprising at least one oxidizing bleaching agent in aqueous solution in the presence of at least one additive which activates delignification or bleaching wherein the activating additive is a phenanthroline selected from the group consisting of 2,9-dimethyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline-disulfonic acid-disodium salt-hydrate, and 3,4,7,8-tetramethyl-1,10-phenanthroline.