Abstract: The purpose of the present invention is to provide a method for producing recycled pulp fibers such that articles using the recycled pulp fibers can easily achieve a uniform whiteness and users are not prone to feel psychological resistance to articles using the recycled pulp fibers. This method is described below.

Abstract: A method of producing conifer-derived pulp fibers for paper includes a beating step of beating conifer-derived material pulp fibers in the presence of a liquid including water; and an ozone treatment step of treating, with ozone water, the beaten conifer-derived material pulp fibers.

Abstract: The purpose of the present disclosure is to provide a method for producing pulp fibres for saccharification from the pulp fibres of used sanitary items, said pulp fibres for saccharification having low lignin contents distributed within a narrow range, and enabling the production of pulp fibres for saccharification having superior saccharification properties.

Abstract: The purpose of the present invention is to provide a method for producing recycled pulp fibers such that articles using the recycled pulp fibers can easily achieve a uniform whiteness and users are not prone to feel psychological resistance to articles using the recycled pulp fibers. This method is described below.

Abstract: A method includes producing recycled products from a plurality of used absorbent articles, each including a top sheet, a back sheet and an absorbent body including absorbent body materials, by recovering a plurality of structural members from the plurality of used absorbent articles. At least one of the top sheet and the back sheet includes a film. The method includes: separating the plurality of used absorbent articles into a plurality of the films and the absorbent body materials; sorting the plurality of films into a plurality of types of recyclable films according to the filler contents of the plurality of films; and forming a plurality of types of recycled resin pellets from the plurality of types of recyclable films.

Abstract: Provided is a method that, when pulp fibers are recovered from used absorbent articles that have been put into collection bags, makes it possible to safely and sanitarily crush the used absorbent articles while suppressing costs. A method for recovering pulp fibers from used absorbent articles, the method comprising: a crushing step (S12) in which collection bags (A) in which used absorbent articles have been sealed are put into a container (65), the collection bags in the container are transferred to a crushing device (12) that communicates with the container, and, bag by bag, the crushing device crushes the used absorbent articles in the collections bags in a deactivating aqueous solution; and a separation step (S13) in which the pulp fibers, a highly water-absorbent polymer, and the deactivating aqueous solution are separated from the crushed product and deactivating aqueous solution obtained in the crushing step.

Abstract: The purpose of the present invention is to provide a method which is for producing pulp fibers for cellulose nanofiberization from pulp fibers of used sanitary products, and which can produce pulp fibers for cellulose nanofiberization that have low lignin content and a low distribution thereof and that have excellent cellulose nanofiberization properties. This method is described below.

Abstract: Recycled pulp that derives from a used sanitary article includes an antibacterial activity value of 2.0 or more and an acid. Recycled pulp that derives from a used sanitary article includes an antibacterial activity value of 2.0 or more and an ash content of 0.65% by weight or less, and further includes an acid. The acid is a citric acid. The recycled pulp further includes a cationic antibacterial agent. The cationic antibacterial agent is a quaternary ammonium salt. The cationic antibacterial agent is a benzalkonium chloride or a cetylpyridinium chloride. At least a portion of the cationic antibacterial agent is adsorbed on the recycled pulp.

Abstract: An absorbent article may include a top sheet that is liquid-permeable, a back sheet that is liquid-impermeable, and an absorbent body situated between the top sheet and the back sheet in a thickness direction. At least one of the top sheet and the back sheet may include a synthetic resin sheet that includes a synthetic resin component and an oxidative decomposer comprising a mixture of a carboxylate and a rare earth compound. The synthetic resin sheet may contain the oxidative decomposer in a mass ratio such that a decomposition rate index (Di), as determined by formula (1), is 7.8 or less: Di=Br×Sa??(1) where Br represents a mass ratio (g/g) of the oxidative decomposer with respect to the synthetic resin component, and Sa represents a specific surface area (cm2/g) of the synthetic resin sheet.

Abstract: A method of recycling superabsorbent polymers derived from a used absorbent article, the method including: treating the superabsorbent polymers with ozone water after inactivation; reactivating, with an alkaline aqueous solution, the superabsorbent polymers treated with the ozone water; and adding hydrophilic fine particles to the superabsorbent polymers reactivated with the alkaline aqueous solution and then drying the superabsorbent polymers.

Abstract: A recycled pulp that is reusable sanitary products is efficiently manufactured by recovering pulp fiber from used sanitary products containing the pulp fiber and a polymer absorbent. The method of the present invention comprises: a step applying a mechanical force to the used sanitary products in an aqueous solution containing a polyvalent metal ion or an acidic aqueous solution with a pH of 2.5 or lower and thus degrading the used sanitary products into the pulp fiber and other materials; a step separating the pulp fiber from the mixture of the pulp fiber and other materials that has been formed in the degradation step; and a step treating the pulp fiber thus separated with an ozone-containing aqueous solution with a pH of 2.5 or lower.

Abstract: Provided is a method for producing pulp fibers to be saccharified, whereby it becomes possible to reduce the amount of a highly water-absorbable polymer and therefore increase the collection efficiency in the production of a saccharified solution when pulp fibers for a saccharified liquid is produced from a dirty absorbent article. The method is a method for producing pulp fibers to be saccharified, from pulp fibers in a dirty absorbent article.

Abstract: A method of producing conifer-derived pulp fibers for paper includes a beating step of beating conifer-derived material pulp fibers in the presence of a liquid including water; and an ozone treatment step of treating, with ozone water, the beaten conifer-derived material pulp fibers.

Abstract: A method of recycling superabsorbent polymers derived from a used absorbent article, the method including: treating the superabsorbent polymers with ozone water after inactivation; reactivating, with an alkaline aqueous solution, the superabsorbent polymers treated with the ozone water; and adding hydrophilic fine particles to the superabsorbent polymers reactivated with the alkaline aqueous solution and then drying the superabsorbent polymers.

Abstract: A method of recovering structural members from a used absorbent article comprising a front sheet, a back sheet and an absorbent body between the front sheet and the back sheet, wherein at least one of the front sheet and the back sheet includes a film, and wherein the absorbent body includes an absorbent body material, may include swelling the used absorbent article with water, applying a physical shock to and disintegrating the swelled used absorbent article into at least the film and the absorbent body material, and separating the film and the absorbent body material.

Abstract: A simple method is provided for producing a saccharified solution from a used absorbent article such as a used diaper. In order to produce a saccharified solution from a used absorbent article comprising a non-cellulosic liquid permeable surface material and an absorbent body that contains pulp fibers, the used absorbent article is immersed, without first being decomposed, in a saccharifying enzyme solution containing cellulase. The pulp fibers in the used absorbent article are saccharified by the cellulase, producing a saccharified solution. The produced saccharified solution is exuded out of the used absorbent article through the liquid permeable surface material, so it is possible to easily separate and recover the saccharified solution from the used absorbent article while maintaining the outer shape.

Abstract: The present invention provides a method which, in the process of manufacturing recycled pulp fibers from a mixture of pulp fibers and a high water-absorption polymer, enables efficient manufacturing of the recycled pulp fibers while properly removing the high water-absorption polymer from the pulp fibers.

Abstract: A recycled pulp that is reusable sanitary products is efficiently manufactured by recovering pulp fiber from used sanitary products containing the pulp fiber and a polymer absorbent. The method of the present invention comprises: a step applying a mechanical force to the used sanitary products in an aqueous solution containing a polyvalent metal ion or an acidic aqueous solution with a pH of 2.5 or lower and thus degrading the used sanitary products into the pulp fiber and other materials; a step separating the pulp fiber from the mixture of the pulp fiber and other materials that has been formed in the degradation step; and a step treating the pulp fiber thus separated with an ozone-containing aqueous solution with a pH of 2.5 or lower.

Abstract: The purpose of the present invention is to provide a recycled pulp fiber manufacturing method with which it is possible to easily obtain recycled pulp fibers containing less of a high water-absorption polymer without requiring any mechanical equipment such as an ozone generation apparatus.

Abstract: The purpose of the present disclosure is to provide a recovery method for an organic acid. The recovery method makes it possible to efficiently recover an organic acid that is included in a deactivating aqueous solution that includes excrement. This recovery method has the following features.