A drainage-optimized additive composition for papermaking is disclosed. The composition comprises an aqueous media and a glyoxalated polyacrylamide (gPAM) resin having a weight average molecular weight (Mw) of at least about 5 MDa. The composition comprises from about 1.95 to about 2.45 wt. % of the gPAM resin. A method of preparing the composition is also disclosed, and comprises preparing a cationic acrylamide (cAM) prepolymer having at least one predetermined property, and selectively glyoxalating the cAM prepolymer by controlling the concentration of the cAM prepolymer in the aqueous media during glyoxalation in relation to the predetermined property. The method may be carried out in situ during a papermaking process (i.e., as an on-site method). A process of forming paper with the composition also disclosed, and comprises combining the composition with the aqueous suspension of cellulosic fibers, forming the cellulosic fibers into a sheet, and drying the sheet to produce a paper.

A drainage-optimized additive composition for papermaking is disclosed. The composition comprises an aqueous media and a glyoxalated polyacrylamide (gPAM) resin having a weight average molecular weight (Mw) of at least about 5 MDa. The composition comprises from about 1.95 to about 2.45 wt. % of the gPAM resin. A method of preparing the composition is also disclosed, and comprises preparing a cationic acrylamide (cAM) prepolymer having at least one predetermined property, and selectively glyoxalating the cAM prepolymer by controlling the concentration of the cAM prepolymer in the aqueous media during glyoxalation in relation to the predetermined property. The method may be carried out in situ during a papermaking process (i.e., as an on-site method). A process of forming paper with the composition also disclosed, and comprises combining the composition with the aqueous suspension of cellulosic fibers, forming the cellulosic fibers into a sheet, and drying the sheet to produce a paper.

Packaging paper consisting of an unbleached kraft paper with a kappa value according to ISO 302:2015 between 38 and 60, preferably between 40 and 58 as base paper, which is optionally coated on at least one side, wherein the kraft paper is made of at least 90% primary pulp, has a basis weight according to ISO 536:2019 between 60 g/m.sup.2 and 150 g/m.sup.2 and an air resistance according to ISO 5636-5:2013 (Gurley) between 5 and 30 seconds, wherein the base paper has an elongation at break in the machine direction according to ISO 1924-3:2005 between 2.5% and 8.5% and has a Bendtsen roughness according to ISO 8791-2:2013 between 70 ml/min and 600 ml/min, preferably between 150 ml/min to 550 ml/min, more preferably 200 ml/min to 500 ml/min, and process for its production.

Packaging paper consisting of an unbleached kraft paper with a kappa value according to ISO 302:2015 between 38 and 60, preferably between 40 and 58 as base paper, which is optionally coated on at least one side, wherein the kraft paper is made of at least 90% primary pulp, has a basis weight according to ISO 536:2019 between 60 g/m.sup.2 and 150 g/m.sup.2 and an air resistance according to ISO 5636-5:2013 (Gurley) between 5 and 30 seconds, wherein the base paper has an elongation at break in the machine direction according to ISO 1924-3:2005 between 2.5% and 8.5% and has a Bendtsen roughness according to ISO 8791-2:2013 between 70 ml/min and 600 ml/min, preferably between 150 ml/min to 550 ml/min, more preferably 200 ml/min to 500 ml/min, and process for its production.

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.

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.

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.

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.

Packaging paper consisting of an unbleached kraft paper with a kappa value according to ISO 302:2015 between 38 and 60, preferably between 40 and 58 as base paper, which is optionally coated on at least one side, wherein the kraft paper is made of at least 90% primary pulp, has a basis weight according to ISO 536:2019 between 60 g/m.sup.2 and 150 g/m.sup.2 and an air resistance according to ISO 5636-5:2013 (Gurley) between 5 and 30 seconds, wherein the base paper has an elongation at break in the machine direction according to ISO 1924-3:2005 between 2.5% and 8.5% and has a Bendtsen roughness according to ISO 8791-2:2013 between 70 ml/min and 600 ml/min, preferably between 150 ml/min to 550 ml/min, more preferably 200 ml/min to 500 ml/min, and process for its production.

Packaging paper consisting of an unbleached kraft paper with a kappa value according to ISO 302:2015 between 38 and 60, preferably between 40 and 58 as base paper, which is optionally coated on at least one side, wherein the kraft paper is made of at least 90% primary pulp, has a basis weight according to ISO 536:2019 between 60 g/m.sup.2 and 150 g/m.sup.2 and an air resistance according to ISO 5636-5:2013 (Gurley) between 5 and 30 seconds, wherein the base paper has an elongation at break in the machine direction according to ISO 1924-3:2005 between 2.5% and 8.5% and has a Bendtsen roughness according to ISO 8791-2:2013 between 70 ml/min and 600 ml/min, preferably between 150 ml/min to 550 ml/min, more preferably 200 ml/min to 500 ml/min, and process for its production.