A softener composition for use in the manufacture of paper includes a softener and an acidic material, wherein the softener composition has a relative acidity (RA) value of more than 0.05.

An object is to provide a base paper for paper tubes that has lower environmental impact and is used for manufacturing of paper tubes offering excellent water resistance. As a solution, a base paper for paper tubes is provided, wherein: it has two or more but no more than five paper layers; the paper layers are bonded by a water-soluble or water-dispersible adhesive; and its elution rate is 2.0 percent or lower.

A novel method for strengthening and reinforcing ancient books is provided. Such treatment method comprises: first placing the ancient books to be treated in a closed strengthening and reinforcing device; after sealing, performing dehumidification operation and vacuumizing operation on system in sequence to maintain the system dry; and after the system is stable under negative pressure, turning on a fan set, directly delivering a strengthening and reinforcing powder to the strengthening and reinforcing device via a gas pipe, or atomizing a strengthening and reinforcing solution through a ultrasonic atomizer and then delivering the atomized solution to the strengthening and reinforcing device via the gas pipe, so that the ancient books to be treated absorb the strengthening and reinforcing agent sufficiently and evenly; and meanwhile monitoring pH value and humidity of the ancient books, thereby implementing strengthening and reinforcement of the ancient books.

A relatively inexpensive papermaking agent having a high concentration and a high molecular weight that exhibits an excellent freeness and paper strength effect obtained using starches which are biomass materials. A papermaking agent which is a (meth)acrylamide polymer containing starches (a1), a (meth)acrylamide (a2), a polymerizable monomer having an amino group (a3), a polymerizable monomer having a carboxy group (a4) and a polymerizable monomer having a sulfonate group (a5) as essential constituent components, wherein the ratio between the amount of the component (a1) used in terms of non-volatile content weight and a total amount of the components (a2) to (a5) used is [(a1)/{(a2)+(a3)+(a4)+(a5)}]=5/95 to 45/55, and wherein the (meth)acrylamide polymer has a non-volatile content concentration of 22 to 35 weight %, and a weight average molecular weight of 1,500,000 to 7,000,000.

[Object] The present invention provides a sulfonated fine cellulose fiber having excellent viscosity and the like, as well as a sulfonated fine cellulose fiber production method capable of efficiently producing the sulfonated fine cellulose fibers.

[Method for Achieving the Object] A fine cellulose fiber obtained by fibrillating a cellulose fiber wherein a part of the hydroxyl groups of the fine cellulose fiber is substituted with sulfo groups, and an introduction amount of sulfur attributable to the sulfo groups is higher than 0.42 mmol/g. The fine cellulose fiber comprises a plurality of unit fibers and has an average fiber width of 30 nm or less. A dispersion liquid in which the fine cellulose fiber is dispersed in a water-soluble solvent at a solid concentration of 0.5% by mass has a viscosity of 5,000 mPa.Math.s or more at 25° C. This makes it possible to obtain the desired viscosity when the fine cellulose fibers are dispersed in a dispersion liquid.

A paper-strengthening agent comprising an amphoteric (meth)acrylamide polymer and an amphoteric (meth)acrylamide polymer, wherein each of constituent monomers of the amphoteric (meth)acrylamide polymer and the amphoteric (meth)acrylamide polymer comprises (meth)acrylamide, a cationic unsaturated monomer, an anionic unsaturated monomer, and a crosslinkable unsaturated monomer, and has a specific weight-average molecular weight, and wherein each viscosity of the paper-strengthening agent, the polymer, and the polymer satisfies a specific relationship.

A paper-strengthening agent comprising an amphoteric (meth)acrylamide polymer and an amphoteric (meth)acrylamide polymer, wherein each of constituent monomers of the amphoteric (meth)acrylamide polymer and the amphoteric (meth)acrylamide polymer comprises (meth)acrylamide, a cationic unsaturated monomer, an anionic unsaturated monomer, and a crosslinkable unsaturated monomer, and has a specific weight-average molecular weight, and wherein each viscosity of the paper-strengthening agent, the polymer, and the polymer satisfies a specific relationship.

The present invention relates to a complex of polymers and to the use thereof in a method of making paper, cardboard or the like. This complex of polymers is obtained by polymerizing water-soluble monomers: in the presence of a host polymer that comprises vinylamine functions and of a non-polymeric transfer agent, and in the absence of a branching or crosslinking agent of the ethylenic polyfunctional type. It is obtained as from a mass ratio of anionic monomer to water that is greater than 0.035.

The present invention relates to a complex of polymers and to the use thereof in a method of making paper, cardboard or the like. This complex of polymers is obtained by polymerizing water-soluble monomers: in the presence of a host polymer that comprises vinylamine functions and of a non-polymeric transfer agent, and in the absence of a branching or crosslinking agent of the ethylenic polyfunctional type. It is obtained as from a mass ratio of anionic monomer to water that is greater than 0.035.

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.