Abstract: 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.

Abstract: 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.

Abstract: Provided are a pitch-formation suppressor and the like which can be widely applied independently of the substance that causes a pitch and of the situation to generate a pitch in a paper manufacturing process, and which can effectively suppress and prevent the troubles due to the pitch, such as foreign spots and defects in a paper, breakage of a paper, and lowering of workability. This pitch-formation suppressor comprises an alkaline solution in which a phenol resin and/or a modified phenol resin is dissolved, or an acid solution in which a phenol resin and/or a modified phenol resin is dissolved.

Abstract: Provided is a method for producing paper and a pitch removal agent that can remove pitch efficiently. A pitch removal agent having an average polymerization degree of 300 to 2500, a saponification index of 70 to 88 mol % and satisfying, when the absorbance at a wavelength of 490 nm is designated as y (Abs) and the saponification index as x (mol %), the Numerical Formula (A) below is added to a pulp slurry during production of paper using waste paper in the step of deinking the waste paper by floatation and/or a step earlier: y=?0.0297x+b??(A) (wherein, 70?x?88 and 2.80?b?3.03).

Abstract: Provided is a method for producing paper and a pitch removal agent that can remove pitch efficiently. A pitch removal agent having an average polymerization degree of 300 to 2500, a saponification index of 70 to 88 mol % and satisfying, when the absorbance at a wavelength of 490 nm is designated as y (Abs) and the saponification index as x (mol %), the Numerical Formula (A) below is added to a pulp slurry during production of paper using waste paper in the step of deinking the waste paper by floatation and/or a step earlier: y=?0.0297x+b??(A) (wherein, 70?x?88 and 2.80?b?3.03).

Abstract: Provided are a pitch-formation suppressor and the like which can be widely applied independently of the substance that causes a pitch and of the situation to generate a pitch in a paper manufacturing process, and which can effectively suppress and prevent the troubles due to the pitch, such as foreign spots and defects in a paper, breakage of a paper, and lowering of workability. This pitch-formation suppressor comprises an alkaline solution in which a phenol resin and/or a modified phenol resin is dissolved, or an acid solution in which a phenol resin and/or a modified phenol resin is dissolved.