Unicharm Corporation

Noritomo Kurita

Takayoshi Konishi

Satoshi Mitsuno

Toshio Hiraoka

Takashi Kato

Kouichi Yamaki

Naoto Ohashi

Yoshihide Ishikawa

Ko Detani

Akihiro Kimura

Takeshi Bandoh

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. The method is characterized by involving: a step for supplying, from a mixed solution supply port () to a treatment tank (), a mixed solution () which contains superabsorbent polymers and pulp fibers derived from multiple types of used sanitary products; a step for supplying an ozone-containing gas () from an ozone-containing gas supply port () to a treatment solution () inside of the treatment tank (); a step in which, by raising the ozone-containing gas () while lowering the superabsorbent polymers and pulp fibers in the treatment tank (), the ozone-containing gas () is brought into contact with the superabsorbent polymers and the pulp fibers, and the pulp fibers are bleached to form recycled pulp fibers; and a step for discharging the treatment solution () from a treatment solution discharge port (), wherein the recycled pulp fibers have a-ΔYI with respect to a standard white plate.

Method for producing recycled pulp fibers, and recycled pulp fibers

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. The method is characterized by involving: a step for supplying, from a mixed solution supply port () to a treatment tank (), a mixed solution () which contains superabsorbent polymers and pulp fibers derived from used sanitary products; a step for supplying an ozone-containing gas () from an ozone-containing gas supply port () to a treatment solution () inside of the treatment tank (); a step in which, by raising the ozone-containing gas () while lowering the superabsorbent polymers and pulp fibers in the treatment tank (), the ozone-containing gas () is brought into contact with the superabsorbent polymers and the pulp fibers, and pulp fibers for cellulose nanofiberization are formed from the pulp fibers; and a step for discharging the treatment solution () from a treatment solution discharge port (), wherein the pulp fibers for cellulose nanofiberization have a lignin content of less than or equal to 0.1 mass %.

Method for producing pulp fibers for cellulose nanofiberization, and pulp fibers for cellulose nanofiberization

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. The production method according to the present disclosure is characterised by comprising the following: a step for supplying a mixed solution () containing pulp fibres and highly-absorbent polymers sourced from used sanitary items to a treatment tank () via a mixed-solution supply port (); a step for supplying an ozone-containing gas () to a treatment solution () within the treatment tank () via an ozone-containing-gas supply port (); a step for lifting the ozone-containing gas () whilst lowering the pulp fibres and highly-absorbent polymers within the treatment tank (), thereby bringing the ozone-containing gas () into contact with the pulp fibres and highly-absorbent polymers, and forming pulp fibres for saccharification from the pulp fibres; and a step for discharging the treatment solution () via a treatment-solution discharge port (). The method is further characterised in that the pulp fibres for saccharification have lignin contents of 0.1% or less.

Method for producing pulp fibres for saccharification, and aqueous solution of pulp fibres for saccharification

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. The method is characterized by involving: a step for supplying, from a mixed solution supply port () to a treatment tank (), a mixed solution () which contains superabsorbent polymers and pulp fibers derived from multiple types of used sanitary products; a step for supplying an ozone-containing gas () from an ozone-containing gas supply port () to a treatment solution () inside of the treatment tank (); a step in which, by raising the ozone-containing gas () while lowering the superabsorbent polymers and pulp fibers in the treatment tank (), the ozone-containing gas () is brought into contact with the superabsorbent polymers and the pulp fibers, and the pulp fibers are bleached to form recycled pulp fibers; and a step for discharging the treatment solution () from a treatment solution discharge port (), wherein the recycled pulp fibers have a-&#x394;YI with respect to a standard white plate.

Method for producing recycled pulp fibers by decomposing super absorbant polymers with ozone

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 (S) in which collection bags (A) in which used absorbent articles have been sealed are put into a container (), the collection bags in the container are transferred to a crushing device () 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 (S) 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.

Method and system for recovering pulp fibers from used absorbent articles

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.

Method for recycling superabsorbent polymer derived from used absorbent article and recycled superabsorbent polymer derived from used absorbent article

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. This method comprises: a supply step (S-) for supplying an aqueous solution containing a mixture () to a driving fluid supply port (DI) of an ejector () and simultaneously supplying, to a suction fluid supply port (AI) of the ejector, a gaseous substance (Z) which is capable of degrading a high water-absorption polymer so as to make the degraded polymer dissolvable; and a treatment step (S-) for discharging, from a mixed fluid discharge port (CO) of the ejector that is connected to a lower part of a treatment tank (), a mixed liquid, which is formed when the aqueous solution and the gaseous substance are mixed within the ejector, into a treatment liquid (P) within the treatment tank, so as to lessen the high water-absorption polymer in the mixture.

Method for manufacturing recycled pulp fibers

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. A method for recovering an organic acid that deactivates a highly water-absorbent polymer that is included in used absorbent articles, the method being characterized by including: a deactivation step (S) in which the highly water-absorbent polymer is immersed in a deactivating aqueous solution that includes an organic acid and has a prescribed pH and the highly water-absorbent polymer is deactivated; a highly water-absorbent polymer removal step (S) in which the deactivated highly water-absorbent polymer is removed from the deactivating aqueous solution; a pH adjustment step (S) in which the deactivating aqueous solution is adjusted to a prescribed pH; a concentration step (S) in which the deactivation step (S), the highly water-absorbent polymer removal step (S), and the pH adjustment step (S) are repeated using deactivating aqueous solution that has gone through the pH adjustment step (S) and the organic acid in the deactivating aqueous solution is concentrated; and an organic acid recovery step (S) in which the organic acid is recovered from the deactivating aqueous solution.

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Kanonji, Japan

Noritomo Kurita