A sheet manufacturing method includes forming a web by accumulating a mixture containing a fiber and a water-soluble polysaccharide in a dry manner, a moisture imparting step of imparting the web with moisture, and a pressurizing and heating step of pressurizing and heating the web to which the moisture is imparted, in which the pressurizing and heating step performs pressurizing and heating at the same time, a pressure higher than a pressure applied to the web in the pressurizing and heating step is not applied to the web before the pressurizing and heating step, and heating to a temperature higher than a temperature for heating the web in the pressurizing and heating step is not performed before the pressurizing and heating step.

A sheet manufacturing method includes forming a web by accumulating a mixture containing a fiber and a water-soluble polysaccharide in a dry manner, a moisture imparting step of imparting the web with moisture, and a pressurizing and heating step of pressurizing and heating the web to which the moisture is imparted, in which the pressurizing and heating step performs pressurizing and heating at the same time, a pressure higher than a pressure applied to the web in the pressurizing and heating step is not applied to the web before the pressurizing and heating step, and heating to a temperature higher than a temperature for heating the web in the pressurizing and heating step is not performed before the pressurizing and heating step.

According to the invention, in producing coloured cardboard, carbon dioxide is injected and dissolved in a mixture of pulp and at least a sulphur dye, while the mixture is pumped with a delivery pressure higher than 200 kPa out of a first pulp reservoir (11) towards a second pulp reservoir (12), and in such manner that the mixture is acidified by the carbon dioxide to become an acidified coloured pulp mixture (14) with a pH-value between 6.5 and 7.0. The acidified coloured pulp is injected under high pressure out of a pulp duct structure (7) into the second pulp reservoir (12) at a distance of at least 2 meter below a level (15) of the acidified coloured pulp mixture (14) in the second pulp reservoir (12). Accordingly, the invention provides a high-quality colouring of cardboard, wherein environmental problems are prevented.

According to the invention, in producing coloured cardboard, carbon dioxide is injected and dissolved in a mixture of pulp and at least a sulphur dye, while the mixture is pumped with a delivery pressure higher than 200 kPa out of a first pulp reservoir (11) towards a second pulp reservoir (12), and in such manner that the mixture is acidified by the carbon dioxide to become an acidified coloured pulp mixture (14) with a pH-value between 6.5 and 7.0. The acidified coloured pulp is injected under high pressure out of a pulp duct structure (7) into the second pulp reservoir (12) at a distance of at least 2 meter below a level (15) of the acidified coloured pulp mixture (14) in the second pulp reservoir (12). Accordingly, the invention provides a high-quality colouring of cardboard, wherein environmental problems are prevented.

The present invention provides methods for obtaining Baobab fibers derived from Baobab trees. The methods include obtaining Baobab plant material, dewatering of the Baobab plant material, and subsequent separation of the dewatered Baobab plant material. The present invention allows a resource-saving separation of the fibers, for example, through a dewatering of the Baobab plant material. Baobab fibers obtained according to the methods of the present invention can be used for a variety of purposes, for instance, for producing chemical pulp, paper, paperboard, carton, special papers, fabrics and fiber-reinforced plastics.

The present invention provides methods for obtaining Baobab fibers derived from Baobab trees. The methods include obtaining Baobab plant material, dewatering of the Baobab plant material, and subsequent separation of the dewatered Baobab plant material. The present invention allows a resource-saving separation of the fibers, for example, through a dewatering of the Baobab plant material. Baobab fibers obtained according to the methods of the present invention can be used for a variety of purposes, for instance, for producing chemical pulp, paper, paperboard, carton, special papers, fabrics and fiber-reinforced plastics.

A process for producing paper or board, which process comprises ad-mixing (I) an aqueous composition of pH ≦6 and (II) at least one water-soluble polymeric anionic compound to a paper stock having a pH in the range from 6 to 8 and then dewatering the paper stock by sheet formation and drying, wherein the aqueous composition comprises (a) polymers having primary amino groups and/or amidine groups to a combined content for these groups of ≧1.5 meq/g of polymer, and (b) 0.01 to 50 mol % of 1,4-cyclohexanedione (b) based on the combined amount of primary amino groups and/or amidine groups of the polymers, and also to the paper or board thus obtained.

The invention relates to a method for preparing aqueous furnish to be used in paper product manufacturing. In the method aqueous furnish is prepared by making a fiber suspension, and cationic natural polymer (S), alum (A) and anionic nanofibrillar cellulose (F) are added to the aqueous furnish in a short circulation of a paper or board machine.

The invention relates to a method for preparing aqueous furnish to be used in paper product manufacturing. In the method aqueous furnish is prepared by making a fiber suspension, and cationic natural polymer (S), alum (A) and anionic nanofibrillar cellulose (F) are added to the aqueous furnish in a short circulation of a paper or board machine.

The disclosure relates to methods and compositions for enhancing the performance of a sizing agent in a papermaking process using a sizing agent enhancer. The sizing agent can be emulsified with an emulsifier and the sizing enhancer can be a polymer comprising at least one primary or secondary amine containing monomer. The method can comprise emulsifying the sizing agent with the emulsifier; and thereafter adding the emulsified sizing agent and the sizing enhancer, separately from or contemporaneously with the emulsified sizing agent, to a fiber furnish of a papermaking process. The combination of the emulsified sizing agent and the sizing enhancer improves the sizing of product paper over the use of the sizing agent without the sizing enhancer. In at least some embodiments, the emulsified sizing agent is ASA emulsified with a polymer comprising at least one primary or secondary amine containing monomer and the sizing enhancer comprises a diallylamine-acrylamide copolymer.