The invention refers to a method to produce a packaging material comprising the steps of; treating at least one surface of a paperboard substrate with a binder and with a metal salt, printing at least a part of said treated surface with ink, and applying at least one polymer layer on said printed surface. The packaging material produced in accordance with the invention shows good printability and simultaneously good adhesion of the applied polymer layer.

Compositions and colloidal particles are provided that may be used to improve a papermaking process. The compositions and colloidal particles may include a polymer and an inorganic salt. A papermaking process carried out using the presently disclosed compositions and colloidal particles may produce a paper product that has increased strength properties.

Compositions and colloidal particles are provided that may be used to improve a papermaking process. The compositions and colloidal particles may include a polymer and an inorganic salt. A papermaking process carried out using the presently disclosed compositions and colloidal particles may produce a paper product that has increased strength properties.

To provide a surface sizing agent for papermaking, which has good low foamability and mechanical stability and has an excellent sizing effect. The surface sizing agent for papermaking is a surface sizing agent for papermaking, comprising a composition obtained by polymerizing unsaturated monomers in the presence of a starch, wherein the amount of the starch is 25 to 40 mass % based on the total amount of the starch and the unsaturated monomers, the unsaturated monomers comprise at least a styrenic compound and a (meth)acrylic ester compound, and the amount of the styrenic compound is 10 mass % or more and less than 30 mass %, and the amount of the (meth)acrylic ester compound is 20 to 50 mass %, based on the total amount of the starch and the unsaturated monomers.

Disclosed is method for on-site glyoxylation of polyacrylamide in a paper or board mill, where a discontinuous batch glyoxylation reaction of aqueous reaction mixture is performed in reactor vessel having driven agitator to form aqueous polymer composition comprising glyoxylated polyacrylamide. The method comprises forming or obtaining the aqueous reaction mixture comprising polyacrylamide base polymer and glyoxal, determining alkali consumption of the mixture, and adding to the mixture, based on determined alkali consumption, pre-determined amount of alkali for adjusting pH to 8-10. The temperature is optionally adjusted to 15-40° C. and the on-site glyoxylation reaction of polyacrylamide base polymer is allowed to proceed. Viscosity of the mixture and/or a variable related to the viscosity is measured, acid is added to the mixture for lowering pH to <8, when a predetermined end viscosity value is attained, and the aqueous polymer composition comprising glyoxylated polyacrylamide is removed from the reaction vessel.

Disclosed is method for on-site glyoxylation of polyacrylamide in a paper or board mill, where a discontinuous batch glyoxylation reaction of aqueous reaction mixture is performed in reactor vessel having driven agitator to form aqueous polymer composition comprising glyoxylated polyacrylamide. The method comprises forming or obtaining the aqueous reaction mixture comprising polyacrylamide base polymer and glyoxal, determining alkali consumption of the mixture, and adding to the mixture, based on determined alkali consumption, pre-determined amount of alkali for adjusting pH to 8-10. The temperature is optionally adjusted to 15-40° C. and the on-site glyoxylation reaction of polyacrylamide base polymer is allowed to proceed. Viscosity of the mixture and/or a variable related to the viscosity is measured, acid is added to the mixture for lowering pH to <8, when a predetermined end viscosity value is attained, and the aqueous polymer composition comprising glyoxylated polyacrylamide is removed from the reaction vessel.

An improved market pulp and process for making the same by adding a composite material are described. The composite material includes cellulose nanocrystals, cellulose nanofibers, or another high aspect ratio, high surface area cellulose material (or a starch, or both) and a crosslinking compound that crosslinks a portion of the surface hydroxyl groups to form a 3-D matrix. Adding the composite material to market pulp has been shown to improve the strength of twice-dried paper products, made from such an enhanced market pulp. By crosslinking a portion of the surface hydroxyl groups in the market pulp to form a 3-D matrix, a first drying step may be accomplished without loss of benefits afforded when the market pulp is later re-pulped to make a paper product.

Treated pulp sheets comprising cellulose pulp fibers treated with a densifying agent and having a relatively low moisture content. In certain embodiments, the treated pulp sheets are used to produce fiberized pulp having low knot content, while maintaining density and softness properties usually associated with similarly treated pulp that is fiberized at higher moisture content. Methods of making fiberized pulp from the treated pulp sheets, as well as products comprising the treated pulp sheets or fiberized pulp from the treated pulp sheets, are also provided.

The invention relates to the use of a surface size composition comprising at least one cellulose derivative selected from cellulose ethers, excluding carboxyalkyl celluloses, for providing compression strength for a fibrous web, such as paper, board or the like, preferably comprising recycled cellulosic fibres. The invention relates also to a method for surface sizing of paper, board or the like.

A composition for addition to a ceiling tile, flooring product, or other construction product may include microfibrillated cellulose and optionally an inorganic particulate material. The ceiling tile, flooring product, or other construction product may further include perlite, mineral wool, wood pulp, starch and other additives, where the wood pulp and other inorganic particulate materials are bonded to the microfibrillated cellulose. Methods of manufacturing the compound are also disclosed.