WO2019087486A1

WO2019087486A1 - Method and system for recovering pulp fibers from used absorbent articles

Info

Publication number: WO2019087486A1
Application number: PCT/JP2018/028145
Authority: WO
Inventors: 孝義小西; 利夫平岡; 加藤　孝; 範朋栗田
Original assignee: ユニ・チャーム株式会社
Priority date: 2017-11-01
Filing date: 2018-07-26
Publication date: 2019-05-09
Also published as: JP2023010724A; AU2023201206B1; RU2020117696A3; CN115722520A; RU2020117696A; JP7446384B2

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.

Description

Method and system for recovering pulp fibers from used absorbent articles

The present invention relates to methods and systems for recovering pulp fibers from used absorbent articles.

Methods are known for recovering pulp fibers from absorbent articles such as used disposable diapers. In the method, when treating a used absorbent article, it is important to suppress the cost by improving the recovery rate of the pulp fibers and the processing efficiency and to improve the hygiene management by reducing the scattering of the dirt of the disposable diaper. Therefore, the collection bag in which a plurality of used absorbent articles are enclosed may be processed as it is. By treating the collection bag as it is, it is possible to reduce the work of taking out used absorbent articles from the collection bag (improvement of processing efficiency) and make it difficult for workers to come in contact with dirt and fungi attached to the used absorbent articles. It can do (improvement of hygiene management).

As such a method, for example, Non-Patent Document 1 discloses a crushing separation and recovery apparatus for used disposable diapers. This apparatus comprises a separation tank, a screen, a stirrer, a crushing means, pulps discharging means, and plastics discharging means. In the separation tank, the used disposable diaper placed in the collection body (bag) is charged together with the collection body, and water, a polymer separating agent and a sterilizing agent are supplied. The screen divides the separation tank into upper and lower chambers. The stirrer is provided in the upper chamber of the separation tank and stirs the treated material (collection bag, used disposable diaper, water, various agents, etc.). The crushing means may be provided in the upper chamber of the separation tank to crush the collection body and the used disposable diaper. The pulp discharging means is provided in communication with the lower chamber of the separation tank to discharge the pulp having passed through the screen. The plastic discharge means is provided in communication with the upper chamber of the separation tank and discharges the plastic which can not pass through the screen under natural flow. According to Non-Patent Document 1, in the prior art, crushing equipment is required in addition to separation and recovery equipment, and a sanitary burden is imposed because the paper diaper in a state in which excrement is attached at the time of crushing treatment is merely crushed. Although large, this device is considered to be able to solve those cost and hygiene problems.

The device of Non-Patent Document 1 integrates the crusher and the separator into one device, and while stirring the water in the separation tank, breaks and collects the collection bag with the same crusher in the water. Crush the used disposable diaper in the bag. Therefore, the water will be in a mixed state of not only crushed disposable diapers but also used disposable diaper dirt and fungi, and the dirt and fungi will scatter outward from the water surface, and the odor associated with the dirt May be released. In that case, in some cases, it may be considered that the worker of the device directly or indirectly contacts dirt or fungi or is exposed to odor during processing or maintenance. When recovering pulp fibers from used absorbent articles placed in a collection bag, it is desirable to have a technique for hygienically and safely crushing used absorbent articles while reducing costs.

An object of the present invention is to be able to hygienically and safely crush the used absorbent article while reducing the cost when recovering pulp fibers from the used absorbent article placed in a collection bag A method and system are provided.

The method for recovering pulp fibers from used absorbent articles containing pulp fibers and superabsorbent polymer in the present invention is as follows. (1) A method of recovering pulp fibers from a used absorbent article containing pulp fibers and a superabsorbent polymer, comprising: receiving a container containing a collection bag in which the used absorbent article is enclosed; and communicating with the container Crushing the used absorbent articles in the collection bag together with the collection bag in the inactivated aqueous solution by the crushing apparatus while transferring the collection bag in the container to the shredding device; And a separation step of separating a pulp fiber, a superabsorbent polymer, and the inactivated aqueous solution from the crushed material obtained in the crushing step and the inactivated aqueous solution by a separation device.
In this method, at least after receiving the collection bag in the container, the collection bag is transferred to a crushing apparatus provided separately from the container, and in the crushing apparatus, the used absorbent in the collection bag is contained in the inactivated aqueous solution. While deactivating the superabsorbent polymer of the article, the used absorbent article is crushed together with the collection bag. That is, when the used absorbent article is crushed, it is crushed in the inactivating aqueous solution in a crushing device separate from the container, and after crushing, the inactivating aqueous solution and the crushed material are transferred to the separation device. Therefore, even if dirt or fungi are mixed in the inactivated aqueous solution or an odor is generated, the inactivated aqueous solution or fragment containing dirt or fungi hardly reaches the container. Therefore, the container can be crushed with little dirt or fungus remaining. In addition, since the odor can be sealed with the inactivating aqueous solution, the generation of the odor can be suppressed to a low level. In particular, when crushing in an inactivated aqueous solution, alkaline volatile components derived from excrement such as urine do not volatilize and remain in the inactivated aqueous solution, so that the generation of odor due to alkaline gas such as ammonia can be suppressed. it can. Thus, when the used absorbent article is crushed, it is possible to suppress the scattering of dirt and fungi and the release of the odor associated with the dirt. That is, it is possible to hygienically and safely crush the used absorbent articles and to suppress the cost of hygiene management in work and maintenance.

In this method, (2) in the receiving step, the collection bag is placed in a solution tank as the container storing the inactivated aqueous solution, and a hole is formed in the surface of the collection bag in contact with the inactivated aqueous solution. The crushing step includes an opening step, and the inside of the collecting bag is transferred from the solution tank to the crushing apparatus together with the inactivating aqueous solution while the hole is opened and the collecting bag which is sunk below the surface of the inactivating aqueous solution is transferred. The method according to (1) above, which comprises the step of crushing the used absorbent article of the above in the inactivated aqueous solution together with the collection bag.
In this method, at least by perforating the collection bag, the inactivated aqueous solution is introduced from the hole into the collection bag to inactivate the superabsorbent polymer contained in the used absorbent article with the inactivated water solution. At the same time, the collection bag is substantially sunk below the surface of the inactivated aqueous solution. As a result, the used absorbent article can be crushed together with the inactivated aqueous solution in the inactivated aqueous solution while transferring the collection bag, which is sunk under the surface of the inactivated aqueous solution, from the solution tank together with the inactivated aqueous solution. Therefore, until the initiation of crushing, the inactivated aqueous solution hardly mixes with dirt and fungi, and no odor is generated. Then, when the used absorbent article is crushed, the inactivated aqueous solution may be mixed with dirt or fungi, or odor may be generated, but the inactivated aqueous solution mixed with dirt or fungi is destroyed at almost the same time as the disruption. The solution is sent out from the solution tank, so that the solution tank can be washed away with almost no dirt or fungus remaining. In addition, since the odor can be sealed with the inactivating aqueous solution, the generation of the odor can be suppressed to a low level. Thus, when the used absorbent article is crushed, it is possible to suppress the scattering of dirt and fungi and the release of the odor associated with the dirt.

The method includes the steps of: (3) drilling holes in the collection bag in the drilling step; and breaking the used absorbent article together with the collection bag in the crushing step at different positions. And the method described in (2) above.
In this method, the steps of piercing the collection bag and crushing the used absorbent article together with the collection bag are performed at different (different) locations (positions). Therefore, after the inactivating aqueous solution is introduced into the collecting bag through the hole and the collecting bag is surely submerged under the surface of the inactivating aqueous solution, crushing can be performed at another location. Therefore, at the time of crushing, a part of the collection bag is exposed on the water surface of the inactivating aqueous solution, and the opening (tear) of the hole is exposed on the water surface of the inactivating aqueous solution. It is possible to suppress the situation of scattering or releasing the odor associated with the contamination.

In the method, (4) the crushing step is a crushing step in which the used absorbent article in the collection bag is crushed in the inactivated aqueous solution supplied together with the collection bag and the collection bag. The method according to the above (2) or (3), including the step of drawing out the crushed material obtained in the in-liquid crushing step from the in-liquid crushing step together with the inactivating aqueous solution, .
In this method, the mixture of the crushed material and the inactivating aqueous solution is actively extracted from the in-liquid crushing step to remove the contamination of the equipment involved in the in-liquid crushing step with the inactivating aqueous solution as the mixture moves (flow Can leave. Thereby, the hygienic state in the crushing process can be kept good.

The method comprises the steps of: (5) forming a hole in the surface of the collection bag in contact with the inactivated aqueous solution in the hole forming step, a projection movable up and down in the solution tank while rotating around a rotation axis The method according to any one of the above (2) to (4) may be performed.
In this method, the collection bag is pierced with projections that move up and down in the solution bath while rotating around the rotation axis. Therefore, even if the collection bag is not settled in the inactivating aqueous solution, the collection bag can be reliably punctured by, for example, moving the protrusion to the top of the volume tank and contacting the collection bag. By drilling the holes and settling the collection bag in the inactivated aqueous solution, the collection bag can be reliably submerged in the acidic solution in a short time, reducing the processing time and increasing the processing efficiency.

The method comprises the steps of: (6) drilling a hole in the surface of the collection bag in contact with the inactivated aqueous solution in the drilling step, feeding the collection bag into the inactivated aqueous solution from the top of the solution tank; The method according to any one of the above (2) to (4), which is disposed at the lower part of the solution tank and is performed by contacting a protrusion rotating around the rotation axis may be used.
In the present method, the collection bag is fed into the inactivating aqueous solution, and the protrusion in the lower part of the solution tank is pierced in the collection bag. Since the collection bag is sedimented in the inactivated aqueous solution and then punctured, it is possible to reliably prevent the spread of dirt and odor from the used absorbent articles in the collection bag to the outside. Thereby, the used absorbent articles can be crushed hygienically and safely.

In the method, (7) the crushing step supplies the collection bag into the inactivated aqueous solution in the crushing apparatus while the used absorbent article in the collection bag is combined with the collection bag. The method according to the above (1) may include the step of crushing in an inactivated aqueous solution.
In this method, the inactivating aqueous solution is stored in advance in a crushing apparatus, and in the inert aqueous solution, the used absorbent articles in the collecting bag are crushed in the inactivating aqueous solution together with the collecting bag. Therefore, the used absorbent articles in the collection bag can be surely crushed together with the collection bag in the inactivated aqueous solution.

(8) The method according to the above (1) or (7), wherein the separation step directly receives the crushed material and the inactivated aqueous solution by the separation device disposed immediately below the crushing device. It may be the method described in
In this method, since the separation device is disposed immediately below the crushing device, the crushed material and the inactivating aqueous solution broken by the crushing device can be transferred to the separation device quickly and reliably. Thereby, even if dirt or fungi are mixed in the inactivated aqueous solution or an odor is generated, their influence can be suppressed lower.

In the method, the crushing step includes the step of crushing the used absorbent article together with the collection bag so that the average size of the crushed material is 50 mm or more and 100 mm or less. The method according to any one of (1) to (8) may be used.
In this method, in the crushing step, crushing is performed such that the average value of the sizes of crushed materials is 50 mm or more and 100 mm or less by adjusting the crushing apparatus. However, the size of the crushed material is the length of the long side in the case of a rectangular shape, the diameter in the case of a circle, and the length of a square corresponding to the area in the case of an irregular shape. In that case, since the back sheet and / or the top sheet of each used absorbent article can be reliably cut, it is possible to take out pulp fibers substantially without leaving the cut in each used absorbent article. As a result, the recovery rate of pulp fibers (total amount of regenerated pulp fibers / total amount of pulp fibers of used absorbent articles supplied) and the recovery rate of superabsorbent polymer can be increased. However, if the average value of the size is less than 50 mm, other materials (example: film (back sheet etc.), non-woven cloth (surface sheet etc.), elastic body (leak prevention wall rubber) other than pulp fiber and super absorbent polymer Etc.) is too small to be separated from the pulp fiber and the superabsorbent polymer. As a result, the pulp fiber to be regenerated and other materials mixed in the superabsorbent polymer are increased, and the recovery rate of the pulp fiber and superabsorbent polymer is reduced. On the other hand, when the average value of the size is larger than 100 mm, it becomes difficult to cut the used absorbent article. As a result, the used absorbent article which can not take out a pulp fiber or a super absorbent polymer will arise, and the recovery of a pulp fiber or a super absorbent polymer will fall.

The method according to the above (1) to (10), wherein in the crushing step, the step of crushing the used absorbent article in the inactivating aqueous solution together with the collection bag in the crushing step is performed by a twin-screw crusher. It may be a method according to any one of 9).
In this method, the step of crushing the used absorbent article is performed using a twin-screw crusher (example: twin-screw rotary crusher, twin-screw differential crusher, twin-screw shear crusher) There is. Therefore, the size of the crushed material can be approximately aligned within a predetermined range. As a result, the crushed material becomes too small, foreign matter is mixed in the pulp fiber, or the crushed material becomes too large, and a used absorbent article from which the pulp fiber can not be taken out is generated, and the recovery rate of the pulp fiber is increased. It is possible to control the situation of falling.

The method according to any one of the above (1) to (10), wherein (11) the inactivated aqueous solution is an acidic aqueous solution.
In this method, since the inactivating aqueous solution is an acidic aqueous solution, the superabsorbent polymer in the used absorbent article can be reliably dewatered and inactivated. In particular, when crushing is performed in an acidic aqueous solution, alkaline volatile components derived from excrement such as urine do not volatilize and remain in the acidic aqueous solution, so that generation of odor due to alkaline gas such as ammonia can be suppressed. As a result, in the crushing step, the used absorbent article does not swell significantly, so crushing can be easily performed, and processing efficiency can be enhanced.

(12) The method according to (11) above, wherein the acidic aqueous solution contains citric acid.
In this method, since the acidic aqueous solution contains citric acid (example: concentration 0.5 to 2.0% by mass), the superabsorbent polymer in the used absorbent article can be dehydrated and inactivated as well as the acid. There is almost no adverse effect on workers due to and corrosion of equipment of each process by acid can be suppressed.

The system used to recover pulp fibers from used absorbent articles comprising pulp fibers and superabsorbent polymers in the present invention is as follows. (13) A system for use in a method of recovering pulp fibers from a used absorbent article comprising pulp fibers and a superabsorbent polymer, comprising: a container for containing a collection bag in which the used absorbent article is enclosed; And a crushing device for crushing the used absorbent article in the collection bag together with the collection bag in the inactivated aqueous solution while the collection bag in the container is transferred. A system comprising a pulp fiber, a superabsorbent polymer and a separation device for separating the inactivated aqueous solution from the obtained crushed material and the inactivated aqueous solution.
In this system, at least after receiving the collection bag in the container, the collection bag is transferred to a crushing apparatus provided separately from the container, and in the crushing apparatus, the used absorbent in the collection bag is contained in the inactivated aqueous solution. While deactivating the superabsorbent polymer of the article, the used absorbent article is crushed together with the collection bag. That is, when the used absorbent article is crushed, it is crushed in the inactivating aqueous solution in a crushing device separate from the container, and after crushing, the inactivating aqueous solution and the crushed material are transferred to the separation device. Therefore, even if dirt or fungi are mixed in the inactivated aqueous solution or an odor is generated, the inactivated aqueous solution or fragment containing dirt or fungi hardly reaches the container. Therefore, the container can be crushed with little dirt or fungus remaining. In addition, since the odor can be sealed with the inactivating aqueous solution, the generation of the odor can be suppressed to a low level. In particular, when crushing in an inactivated aqueous solution, alkaline volatile components derived from excrement such as urine do not volatilize and remain in the inactivated aqueous solution, so that the generation of odor due to alkaline gas such as ammonia can be suppressed. it can. Thus, when the used absorbent article is crushed, it is possible to suppress the scattering of dirt and fungi and the release of the odor associated with the dirt. That is, it is possible to hygienically and safely crush the used absorbent articles and to suppress the cost of hygiene management in work and maintenance.

In this system, (14) the solution tank as the container for storing the inactivated aqueous solution, and the inactivated solution in the collection bag provided in the solution tank and the collection bag is placed in the solution tank And the crushing apparatus includes the perforation device for making a hole in the surface in contact with the surface, wherein the crushing apparatus is configured to open the hole and sink the collection bag sunk under the surface of the inactivating aqueous solution, the inactivating aqueous solution The system according to (13), wherein the used absorbent article in the collection bag is crushed in the inactivated aqueous solution together with the collection bag while being transferred from the solution tank to the crushing apparatus together with the Good.
In the present system, at least by perforating the collection bag, the inactivated aqueous solution is introduced from the hole into the collection bag to inactivate the superabsorbent polymer contained in the used absorbent article with the inactivated water solution. At the same time, the collection bag is substantially sunk below the surface of the inactivated aqueous solution. As a result, the used absorbent article can be crushed together with the inactivated aqueous solution in the inactivated aqueous solution while transferring the collection bag, which is sunk under the surface of the inactivated aqueous solution, from the solution tank together with the inactivated aqueous solution. Therefore, until the initiation of crushing, the inactivated aqueous solution hardly mixes with dirt and fungi, and no odor is generated. Then, when the used absorbent article is crushed, the inactivated aqueous solution may be mixed with dirt or fungi, or odor may be generated, but the inactivated aqueous solution mixed with dirt or fungi is destroyed at almost the same time as the disruption. The solution is sent out from the solution tank, so that the solution tank can be washed away with almost no dirt or fungus remaining. In addition, since the odor can be sealed with the inactivating aqueous solution, the generation of the odor can be suppressed to a low level.

The present system may be (15) the system according to (14), wherein the bag opening apparatus and the crushing apparatus are different apparatuses.
In this system, a bag-breaking device for piercing the collection bag and a crushing device for breaking the used absorbent article together with the collection bag are different devices. Therefore, since the opening of the hole and the crushing of the used absorbent article can be surely performed at different places (locations), the inactivating aqueous solution is introduced from the hole into the collection bag, and the collecting bag is made of the inactivating aqueous solution. It can be crushed at another location after it is definitely submerged below the water surface. Therefore, at the time of crushing, a part of the collection bag is exposed on the surface of the inactivated aqueous solution, and the opening (tear) of the hole is exposed on the surface of the inactivated aqueous solution, causing dirt and fungi of used disposable diapers. Can be prevented from being scattered or the odor associated with the dirt being released.

The present system comprises: (16) a crushing unit for crushing the used absorbent articles in the collection bag in the inactivated aqueous solution supplied together with the collection bag and the collection bag; The system according to (14) or (15), including a pump for drawing out the crushed material obtained in the crushing part from the crushing part together with the inactivating aqueous solution.
In this system, by actively extracting the mixture of the crushed material and the inactivating aqueous solution from the crushing part with a pump, the dirt of the crushing part can be removed (flushed away) by the inactivating aqueous solution as the mixture moves. . This makes it possible to maintain good hygiene in the crushing apparatus.

(17) The system according to any one of (14) to (16), wherein in the bag-breaking apparatus, the holed portion includes a projection that can move up and down in the solution tank while rotating around a rotation axis. The system according to any one of the above.
In this system, a hole is formed in the collection bag by a projection moving up and down in the solution tank while rotating around the rotation axis. Therefore, even if the collection bag is not settled in the inactivating aqueous solution, the collection bag can be reliably punctured by, for example, moving the protrusion to the top of the volume tank and contacting the collection bag. By drilling the holes and settling the collection bag in the inactivated aqueous solution, the collection bag can be reliably submerged in the acidic solution in a short time, reducing the processing time and increasing the processing efficiency.

The present system comprises: (18) in the bag-breaking apparatus, the perforation part is disposed at a lower part of the solution tank, a feeding part for feeding the collection bag into the inactivated aqueous solution from the upper part of the solution tank, The system according to any one of the above (14) to (16), including a projection rotating around an axis to puncture the collection bag.
In the present system, the collection bag is pierced into the collection bag with the lower projections of the solution bath, which feed the collection bag into the inactivating aqueous solution. Since the collection bag is sedimented in the inactivated aqueous solution and then punctured, it is possible to reliably prevent the spread of dirt and odor from the used absorbent articles in the collection bag to the outside. Thereby, the used absorbent article can be crushed hygienically and safely.

In the method, (19) the crushing apparatus is configured to supply the used absorbent articles in the collection bag together with the collection bag while the collection bag is supplied into the inactivated aqueous solution in the crushing apparatus. The system according to (13) above may be disrupted in an inactivated aqueous solution.
In this system, the inactivating aqueous solution is stored in advance in a crushing apparatus, and the used absorbent articles in the collecting bag are crushed in the inactivating aqueous solution in the inert aqueous solution. Therefore, the used absorbent articles in the collection bag can be surely crushed together with the collection bag in the inactivated aqueous solution.

The method according to (13) or (19), wherein (20) the separation device is disposed directly below the crushing device and directly receives the crushed material and the inactivating aqueous solution from the crushing device. The system of
In this system, since the separation device is disposed immediately below the crushing device, the crushed material and the inactivated aqueous solution broken by the crushing device can be transferred to the separation device quickly and reliably. Thereby, even if dirt or fungi are mixed in the inactivated aqueous solution or an odor is generated, their influence can be suppressed lower.

The present system (21) the crushing apparatus crushes the used absorbent article together with the collection bag so that the average size of the crushed material is 50 mm or more and 100 mm or less. The system according to any one of (20) to (20).
In this system, crushing is performed such that the average value of the sizes of crushed materials is 50 mm or more and 100 mm or less by adjusting the crushing apparatus. However, the size of the crushed material is as described above such as the length of the long side when the shape is rectangular. In that case, since the back sheet and / or the top sheet of each used absorbent article can be reliably cut, it is possible to take out pulp fibers substantially without leaving the cut in each used absorbent article. Thereby, the recovery rate of the pulp fiber and the recovery rate of the superabsorbent polymer can be increased. However, when the average value of the size is less than 50 mm, materials other than the pulp fiber and the superabsorbent polymer are cut too small, and it becomes difficult to separate the pulp fiber and the superabsorbent polymer. As a result, the pulp fiber to be regenerated and other materials mixed in the superabsorbent polymer are increased, and the recovery rate of the pulp fiber and superabsorbent polymer is reduced. On the other hand, when the average value of the size is larger than 100 mm, it becomes difficult to cut the used absorbent article. As a result, the used absorbent article which can not take out a pulp fiber or a super absorbent polymer will arise, and the recovery of a pulp fiber or a super absorbent polymer will fall.

(22) The system according to any one of (13) to (21), wherein the crusher includes a twin-screw crusher.
In this system, a twin-screw crusher (example: twin-screw rotary crusher, twin-screw differential crusher, twin-screw shear crusher) is used as a crusher for used absorbent articles. Therefore, the size of the crushed material can be approximately aligned within a predetermined range. As a result, the crushed material becomes too small, foreign matter is mixed in the pulp fiber, or the crushed material becomes too large, and a used absorbent article from which the pulp fiber can not be taken out is generated, and the recovery rate of the pulp fiber is increased. It is possible to control the situation of falling.

The system may be (23) the system according to any one of (13) to (22), wherein the inactivated aqueous solution is an acidic aqueous solution.
In this system, since the inactivating aqueous solution is an acidic aqueous solution, the superabsorbent polymer in the used absorbent article can be reliably dewatered and inactivated. In particular, when crushing is performed in an acidic aqueous solution, alkaline volatile components derived from excrement such as urine do not volatilize and remain in the acidic aqueous solution, so that generation of odor due to alkaline gas such as ammonia can be suppressed. As a result, in the crushing step, the used absorbent article does not swell significantly, so crushing can be easily performed, and processing efficiency can be enhanced.

The system may be (24) a system according to (23) above, wherein the acidic aqueous solution comprises citric acid.
In this system, since the acidic aqueous solution contains citric acid (example: concentration 0.5 to 2.0% by mass), the superabsorbent polymer in the used absorbent article can be dehydrated and inactivated, as well as the acid. There is almost no adverse effect on workers due to and corrosion of equipment of each process by acid can be suppressed.

According to the method and system of the present invention, when recovering pulp fibers from a used absorbent article placed in a collection bag, the used absorbent article can be hygienically and safely crushed while suppressing costs. It becomes possible.

It is a block diagram showing an example of a system concerning an embodiment. It is a schematic diagram which shows the structural example of the bag-breaking apparatus of FIG. 1, and a crushing apparatus. It is a schematic diagram which shows the other structural example of the bag-opening apparatus of FIG. 1, and a crushing apparatus. It is the elements on larger scale which show the structural example of the crushing apparatus of FIG. It is a flowchart which shows an example of the method concerning embodiment. It is a block diagram which shows the other example of the system which concerns on embodiment. It is a schematic diagram which shows the structural example of the crushing separation apparatus of FIG. It is a flowchart which shows the other example of the method concerning embodiment. It is a graph which shows the relationship between the magnitude | size of a crushed material and the amount of processing, and the amount of foreign materials in a crushing process.

Hereinafter, a method of recovering pulp fibers from a used absorbent article containing pulp fibers and a superabsorbent polymer according to the embodiment will be described. However, a used absorbent article is an absorbent article used by the user, and includes an absorbent article in a state where it absorbs and holds the user's excrement, and although it is used, it absorbs the excrement. It includes items that are not held and those that are unused but discarded. As an absorbent article, a disposable diaper, a urine absorption pad, a sanitary napkin, a bed sheet, and a pet sheet are mentioned, for example. The method for recovering pulp fibers from the used absorbent article according to the present embodiment can be said to be a method for producing recycled pulp fibers from used absorbent articles because recycled pulp fibers are produced. Furthermore, in the method for recovering pulp fibers from the used absorbent article according to the present embodiment, the super absorbent polymer is recovered along with the pulp fibers along the way, and the recycled super absorbent polymer is generated by separation. It can also be said to be a method for recovering superabsorbent polymer from absorbent articles or a method for producing recycled superabsorbent polymer. Here, it demonstrates as a method of collect | recovering a pulp fiber from a used absorbent article.

First Embodiment
The first embodiment will be described.
First, a configuration example of the absorbent article will be described. The absorbent article comprises a top sheet, a back sheet, and an absorber disposed between the top sheet and the back sheet. An example of the size of the absorbent article includes a length of about 15 to 100 cm and a width of 5 to 100 cm. In addition, the absorbent article may further contain other members, such as a diffusion sheet, a leak-barrier, etc. with which a general absorbent article is provided.

As a structural member of a surface sheet, the nonwoven fabric of liquid permeability, the synthetic resin film which has a liquid permeation hole, the composite sheet of these, etc. are mentioned, for example. As a structural member of a back surface sheet, the liquid impervious nonwoven fabric, the liquid impervious synthetic resin film, and these composite sheets are mentioned, for example. As a structural member of a diffusion sheet, a liquid permeable nonwoven fabric is mentioned, for example. Examples of the component of the leak-proof wall include a liquid-impervious non-woven fabric, and may include an elastic member such as rubber. Here, the material of the non-woven fabric and the synthetic resin film is not particularly limited as long as it can be used as an absorbent article, but, for example, olefin resins such as polyethylene and polypropylene, and polyamides such as 6-nylon and 6,6-nylon And polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). In the present embodiment, an absorbent article in which the constituent member of the back sheet is a film and the constituent member of the top sheet is a non-woven fabric will be described as an example.

The components of the absorber include absorber materials, i.e. pulp fibers and superabsorbent polymers. The pulp fiber is not particularly limited as long as it can be used as an absorbent article, and examples thereof include cellulosic fibers. Examples of cellulose fibers include wood pulp, crosslinked pulp, non-wood pulp, regenerated cellulose, semi-synthetic cellulose and the like. As the size of the pulp fiber, for example, an average value of the major axis of the fiber may be several tens μm, preferably 20 to 40 μm, an average value of the fiber length may be several mm, for example 2 to 5 mm. The super absorbent polymer (SuperAbsorbent Polymer: SAP) is not particularly limited as long as it can be used as an absorbent article, but for example, a polyacrylate based, polysulfonate based, and anhydrous maleate based water absorbing polymer It can be mentioned. The size (at the time of drying) of the superabsorbent polymer is, for example, several hundred μm in average particle diameter, preferably 200 to 500 μm.

One side and the other side of the absorber are respectively bonded to the top sheet and the back sheet via an adhesive. In a plan view, a portion (peripheral portion) of the top sheet extending to the outside of the absorber so as to surround the absorber is a portion on the outside of the absorber so as to surround the absorber of the back sheet. It is joined with the extended part (peripheral part) via an adhesive. Therefore, the absorber is encased within the joined body of the top sheet and the back sheet. The adhesive is not particularly limited as long as it can be used as an absorbent article and the bonding strength is reduced by softening or the like with warm water described later, and examples thereof include a hot melt adhesive. As a hot-melt adhesive, for example, a pressure-sensitive adhesive or a heat-sensitive adhesive mainly composed of rubber such as styrene-ethylene-butadiene-styrene, styrene-butadiene-styrene, styrene-isoprene-styrene or olefin based such as polyethylene Agents.

Next, a method of recovering pulp fibers from a used absorbent article containing pulp fibers and a superabsorbent polymer according to the embodiment will be described. In this embodiment, used absorbent articles are recovered and obtained from the outside for reuse (recycling). At that time, a plurality of used absorbent articles are enclosed in a collection bag (hereinafter also referred to as “collection bag”) so that dirt (excrements etc.), fungi and odor do not leak to the outside. ing. The individual used absorbent articles in the collection bag are mainly rolled up inside the surface sheet on which the excrement is excreted so that the excrement is not exposed to the front side and the odor is not diffused to the surroundings. It is recovered etc. in the closed or folded state.

First, a system 1 used in a method of recovering pulp fibers from a used absorbent article will be described. System 1 is a system for recovering pulp fibers (preferably further super absorbent polymer) from used absorbent articles and thus producing recycled pulp fibers (preferably further recycled super absorbent polymer). FIG. 1 is a block diagram showing an example of a system 1 according to the present embodiment. The system 1 comprises a bag removing device 11 and a shredding device 12. Preferably, the first separating device 13, the first dust removing device 14, the second dust removing device 15, the third dust removing device 16, and the third A second separation device 17, a third separation device 18, an oxidant processing device 19, and a fourth separation device 20 are provided. The details will be described below.

First, the bag tearing apparatus 11 and the shredding apparatus 12 will be described. The bag-breaking device 11 punctures the collection bag containing the used absorbent article in the inactivated aqueous solution. The crusher 12 crushes the used absorbent articles in the inactivated aqueous solution, which is sunk below the surface of the inert aqueous solution, together with the collection bag. However, the inactivating aqueous solution is an aqueous solution which inactivates the super absorbent polymer, and the water absorption performance of the super absorbent polymer is lowered by the inactivation. Thereby, the superabsorbent polymer releases water, i.e. dehydrates, to an amount that is acceptable for water absorption if it is absorbing more water than the reduced water absorption capacity. Below, the case where an acidic aqueous solution is used as an inactivation aqueous solution is demonstrated to an example.

FIG. 2 is a schematic view showing a configuration example of the bag removing device 11 and the crushing device 12 of FIG.
The bag-breaking apparatus 11 stores, for example, the acidic aqueous solution B supplied via a pipe provided with a valve, and punctures the collection bag A placed in the acidic aqueous solution B. The bag-breaking apparatus 11 includes a solution tank (container) V and a piercing unit 50. The solution tank V holds the acidic aqueous solution B. The perforations 50 are provided in the solution tank V, and when the collection bag A is placed in the solution tank V, holes are formed in the surface of the collection bag A in contact with the acidic aqueous solution B.
The piercing unit 50 includes a feeding unit 30 and a bag opening 40. The feed unit 30 feeds (pulls) the collection bag A into the acidic aqueous solution B in the solution tank V (physically forced). The feed unit 30 is, for example, a stirrer, and includes a stirring blade 33, a support shaft (rotary shaft) 32 for supporting the stirring blade 33, and a drive device 31 that rotates the support shaft 32 along the axis. The stirring blade 33 rotates around the rotation shaft (support shaft 32) by the drive device 31 to generate a swirling flow in the acidic aqueous solution B. The feed unit 30 draws the collection bag A toward the bottom of the acidic aqueous solution B (solution tank V) by the swirling flow.
The tear-off portion 40 is disposed at the lower portion (preferably the bottom) of the solution tank V, and the tear-off blade 41, a support shaft (rotation shaft) 42 for supporting the tear-off blade 41, and the support shaft 42 And a driving device 43 that rotates along with the driving device. The tearing blade 41 makes a hole in the collection bag A moved to the lower part of the acidic aqueous solution B (solution tank V) by rotating around the rotating shaft (supporting shaft 42) by the drive device 43. However, the lower part of the solution tank V indicates a portion below the half position in the height direction of the solution tank V.
The tearing blade 41 of the punching portion 50 of the tearing device 11 may move up and down in the solution tank V while rotating around the rotation shaft (supporting shaft 42). In that case, by moving the tear-off blade 41 upward, even if the collection bag A does not move to the lower part of the acidic aqueous solution B (solution tank V), a hole can be made in the collection bag A.

The crushing apparatus 12 crushes the used absorbent articles in the collection bag A sunk below the surface of the acidic aqueous solution B together with the collection bag A. The crushing apparatus 12 includes a crushing unit 60 and a pump 63. The crushing part 60 is connected by the solution tank V and the pipe 61, and by opening the valve (not shown) of the pipe 61, the inside of the collection bag A is sent together with the acidic aqueous solution B from the solution tank V mainly by gravity. The used absorbent article (mixed liquid 91) is crushed in the acidic aqueous solution B together with the collection bag A. As the crushing part 60, a twin screw crusher (example: twin screw rotary crusher, twin screw differential crusher, twin screw shearing crusher) may be mentioned, and for example, a smear cutter (Sumitomo Heavy Industries Environment Co., Ltd.) Manufactured by The pump 63 is connected by the crushing unit 60 and the pipe 62, and the crushed material obtained in the crushing unit 60 is drawn out from the crushing unit 60 together with the acidic aqueous solution B (mixed liquid 92) and delivered to the next process. However, the crushed material includes pulp fiber and super absorbent polymer, and other materials (material of collection bag A, film, nonwoven fabric, elastic body, etc.). It is preferable that the bag removing device 11 and the shredding device 12 be different devices.

FIG. 3 is a schematic view showing another configuration example of the bag removing device 11 and the crushing device 12 of FIG. In the example of FIG. 3, the configuration of the bag tearing device 11 is different from that of FIG. 2. The bag-breaking apparatus 11 includes a solution tank Va and a perforation 50a. The piercing portion 50a includes a feeding portion 30a and a tear-off portion 40a. The feeding unit 30a feeds (pushes) the collection bag A (physically and forcibly) into the acidic aqueous solution B in the solution tank Va. The feeding portion 30a is directly connected to the upper portion of the solution tank Va, and has a cylindrical member 38, a shaft member 36 disposed in the cylindrical member 38 so as to overlap with the axis of the cylinder, and a shaft around the shaft member 36. And a plate member 37 that spirals along the direction. By pushing the collecting bag A one after another along the spiral of the plate-like member 37 from above the feeding part 30a, the collecting bag A is fed from below the feeding part 35 into the solution tank Va filled with the acidic aqueous solution B. Be
The punctured portion 40a is disposed to extend from the bottom of the solution tank Va to the inside, and the rotating rotor 41a, a supporting shaft (rotating shaft) 42 for supporting the rotating rotor 41a, and the supporting shaft 42 along the axis. And a driving device 43 that rotates. The rotating rotor 41 a has a conical main body 45 and a plurality of protrusions 44 disposed on the side surface of the main body 45. The rotating rotor 41a rotates around the rotation shaft (supporting shaft 42) in the acidic aqueous solution B (solution tank Va) to move the plurality of projections to the collection bag A which has been moved into the acidic aqueous solution B (solution tank Va). Make a hole in section 44. As what integrated the broken bag part 40a and the solution tank Va, mixer pulper (made by Aikawa Tekko Co., Ltd.) is mentioned, for example.

FIG. 4 is a partially enlarged view showing a structural example of the crushing unit 60 of the crushing apparatus 12 of FIG. The biaxial crusher of the crusher 60 is provided with a pair of

rotation shafts

72, 72 rotatably supported at both ends by the housing 75 and arranged in parallel to each other. The rotary shafts 72 are mutually rotated toward the inside of the housing 75 by a drive device 71 (not shown). The rotary blades 74 and the spacers 73 are alternately mounted on the rotary shafts 72 in the axial direction. The dimensions and arrangement of the rotary blade 74 and the spacer 73 in each rotary shaft 72 and the distance between the

rotary shafts

72 and 72 so that the rotary blade 74 and the spacer 73 mounted on the pair of rotary shafts 72 face each other and mesh with each other. Is set. At this time, the size of the crushed material can be adjusted mainly by the difference a in the radius between the rotary blade 74 and the spacer 73 and the axial thickness b of the rotary blade 74. For example, when the average value of the size (plan view) of the crushed material is set to a size of about 60 mm square, the size can be realized by adjusting so that aab ≒ 60 mm. However, the size of the crushed material is the length of the long side when the shape of the crushed material in a plan view is substantially rectangular, and in the case of an irregular type, the size of the square when approximated by a square having the same area as the crushed material. The length of one side, in the case of a circle, is the diameter. The average size of crushed material is the crushed material immediately after crushing, and 10 pieces of crushed material (example: top sheet or back sheet etc.) having an area larger than a × b before crushing are arbitrarily selected , Calculate the average value.

Referring to FIG. 1, the first separation device 13 is a wash that stirs the liquid mixture 92 containing the crushed material obtained by the crushing device 12 and the acidic aqueous solution to remove dirt (excrement etc.) from the crushed material. The pulp fiber, the superabsorbent polymer and the acidic aqueous solution are separated from the mixed solution 92 (mixed solution 93) and sent to the first dust remover 14.
The first separation device 13 may be, for example, a washing machine equipped with a washing and dewatering tank and a water tub surrounding the same. However, a washing tank and dewatering tank (rotary drum) is used as a washing tank and sieving tank (separation tank). The size of the plurality of through holes provided on the circumferential surface of the washing tank is such that pulp fibers and highly water-absorptive polymer in the crushed material can easily pass through and other materials can not easily pass through. Examples of the washing machine include a horizontal washing machine ECO-22B (manufactured by Inamoto Seisakusho Co., Ltd.).

In addition, when an acidic aqueous solution is not used as the inactivating aqueous solution between the bag removing device 11 to the first separation device 13, the acidic aqueous solution is added from the first dust removing device 14 and the pulp supplied to the first dust removing device 14 The inactivated aqueous solution containing the fiber and the superabsorbent polymer may be a substantially acidic aqueous solution. In that case, the specific gravity and size of the superabsorbent polymer can be easily adjusted by pH.

The first dust remover 14 has a plurality of openings with an acidic aqueous solution (mixed liquid 93) containing pulp fibers and super absorbent polymer delivered from the first separator 13 while maintaining the pH within a predetermined range. The screen separates the pulp fiber and the superabsorbent polymer (mixed liquid 94) in the acidic aqueous solution and other materials (foreign matter). In order to maintain the pH within a predetermined range, for example, a liquid (example: water) that causes pH to change halfway is not added, or, in the case of adding a liquid, a liquid with substantially the same pH (example: (Acidic aqueous solution) The predetermined range is a range of fluctuation of pH within ± 1.0.
The first dust remover 14 is, for example, a screen separator (coarse screen separator). However, the openings of the screen (sieve) are not particularly limited, and examples thereof include slits, round holes, square holes, and meshes. Here, round holes are used. The size of the opening, that is, the size (diameter) of the round hole is such a size that the pulp fiber and the superabsorbent polymer can pass, and other materials (foreign material) which can not be removed by the first separating device 13 can not pass easily And the size of the opening of the screen of the second dust remover 15. The size of the round hole is, for example, 2 to 5 mm in diameter, whereby other materials (foreign matter) of at least about 10 mm square can be removed. In the case of the slit, the size (width) of the slit is, for example, 2 to 5 mm.
From the viewpoint of improving the efficiency of foreign matter removal, the mixed solution 93 delivered from the first separating device 13 may be supplied to the first dust removing device 14 while being pressurized (example: 0.5 to 1 kgf / cm ² ). Good. Examples of the first dust remover 14 include pack pulper (manufactured by Satomi Seisakusho Co., Ltd.).

The second dust remover 15 has a plurality of openings with an acidic aqueous solution (mixed liquid 94) containing pulp fibers and super absorbent polymer delivered from the first dust remover 14 while maintaining the pH within a predetermined range. The screen separates the pulp fiber and the superabsorbent polymer (mixed liquid 95) in the acidic aqueous solution and other materials (foreign matter).
The second dust remover 15 is, for example, a screen separator. However, the opening of the screen (sieve) is not particularly limited, and examples thereof include slits, round holes, square holes, and meshes. Here, slits are used. The size (width) of the slit is a size through which the pulp fiber and the superabsorbent polymer can pass, and the size through which other materials (foreign matter) which can not be removed by the first dust remover 14 can not pass easily. The size of the slit is, for example, 0.2 to 0.5 mm in width, whereby other materials (foreign matter) of at least about 3 mm square can be removed. In the case of a round hole, the size (diameter) of the round hole is, for example, 0.2 to 0.5 mm in diameter.
From the viewpoint of improving the efficiency of foreign matter removal, the mixed solution 94 delivered from the first dust removing device 14 may be supplied to the second dust removing device 15 while being pressurized (example: 0.5 to 2 kgf / cm ² ). Good. The pressure is preferably higher than the pressure of the first dust remover 14 from the viewpoint of removing relatively small foreign matter. Examples of the second dust remover 15 include Lamo Screen (manufactured by Aikawa Tekko Co., Ltd.).

The third dust remover 16 centrifuges the acidic aqueous solution (mixed liquid 95) containing the pulp fiber and the superabsorbent polymer delivered from the second dust remover 15, while maintaining the pH within a predetermined range, Pulp fibers and super absorbent polymer (mixed liquid 96) in an acidic aqueous solution and other materials (foreign matter) are separated.
The third dust remover 16 is, for example, a cyclone separator. Pulp fiber and super absorbent polymer at a predetermined flow rate so that pulp fibers and super absorbent polymer in an acidic aqueous solution having a relatively low specific gravity rise and foreign substances (such as metals) having a higher specific gravity lower than those. Is supplied into an inverted conical housing (not shown) of the third dust remover 16. The third dust remover 16 is exemplified by an ACT low concentration cleaner (manufactured by Aikawa Tekko Co., Ltd.).

The second separation device 17 mixes the pulp fiber in the acidic aqueous solution (mixture 96) with the pulp aqueous solution (mixed liquid 96) containing the pulp fiber and the superabsorbent polymer delivered from the third dust collector 16 by the screen having a plurality of openings. The solution 97) and the superabsorbent polymer in an acidic aqueous solution are separated. Therefore, it can also be viewed as a dehydrator that removes the acidic aqueous solution from the liquid mixture 96 together with the superabsorbent polymer.
The second separation device 17 is, for example, a drum screen separator. However, the opening of the drum screen (sieve) is not particularly limited, and may be, for example, a slit, a round hole, a square, or a mesh hole. Here, a slit is used. The size (width) of the slit is a size through which the superabsorbent polymer can pass and a size through which the pulp fiber can not pass easily. In the case of a slit, the size of the slit is, for example, 0.2 to 0.8 mm wide, which allows at least many superabsorbent polymers to be removed. In the case of a round hole, the size of the round hole is, for example, 0.2 to 0.8 mm in diameter. Examples of the second separation device 17 include a drum screen dehydrator (manufactured by Toyo Screen Co., Ltd.).

The third separation device 18 is a pulp fiber and a high water content polymer that has been delivered from the second separation device 17, and the superabsorbent polymer remaining after separation and the acidic aqueous solution (mixture liquid 97) with a screen having a plurality of openings. While separating into a solid (mixture 98) containing a water absorbing polymer and a liquid containing a high water absorbing polymer and an acidic aqueous solution, pressure is applied to the solid to crush the high water absorbing polymer in the solid. Therefore, the third separation device 18 can also be viewed as a pressure dehydration type dehydrator that removes the acidic aqueous solution from the liquid mixture 97 together with the superabsorbent polymer. However, the solid (mixture 98) contains some acidic water solubility.
The third separation device 18 is, for example, a screw press dehydrator. A cylindrical drum screen, a screw shaft extending along an axis of a cylinder of the drum screen, and screw blades provided on an outer side of the screw shaft and rotating along an inner circumferential surface of the drum screen. However, the opening of the drum screen (sieve) is not particularly limited, and may be, for example, a slit, a round hole, a square, or a mesh hole. Here, a slit is used. The size (width) of the slit is a size through which the superabsorbent polymer can pass and a size through which the pulp fiber can not pass easily. In the case of a slit, the size of the slit is, for example, 0.1 to 0.5 mm in width, and at least the remaining superabsorbent polymer can be removed. The third separation device 18 delivers the liquid containing the superabsorbent polymer and the acidic aqueous solution from the slit of the side surface of the drum screen, and the pulp fiber and the superabsorbent polymer from the gap of the lid in which the pressure of the tip of the drum screen is adjusted. The solids contained are delivered while crushing the superabsorbent polymer. The pressure applied to the lid may be, for example, 0.01 MPa or more and 1 MPa or less. As the third separation device 18, a screw press dehydrator (manufactured by Kawaguchi Seiki Co., Ltd.) may be mentioned.

The oxidizing agent processing unit 19 processes the pulp fiber (mixture 98) containing the crushed super absorbent polymer in the solid delivered from the third separating unit 18 with an aqueous solution (processing solution) containing an oxidizing agent. Thereby, the superabsorbent polymer is oxidatively decomposed to be removed from the pulp fibers, and the pulp fibers not containing the superabsorbent polymer are delivered together with the treatment liquid (mixed liquid 99).
When using an ozone as an oxidizing agent, an oxidizing agent processing apparatus is equipped with a processing tank and an ozone supply apparatus, for example. The treatment tank stores the acidic aqueous solution as a treatment liquid. An ozone supply apparatus supplies ozone containing gas which is a gaseous substance to a processing tank. Examples of the ozone generator of the ozone supply apparatus include an ozone water exposure tester ED-OWX-2 manufactured by Ecodesign Co., Ltd. and an ozone generator OS-25V manufactured by Mitsubishi Electric Corporation. The nozzle of the ozone supply device is disposed at the lower part of the treatment tank and has, for example, a tubular or flat shape. The nozzle supplies the ozone-containing gas Z into the processing liquid as a plurality of fine bubbles. As the treatment liquid, an acidic aqueous solution is preferable from the viewpoint of suppressing the deactivation of ozone and the inactivation of the super absorbent polymer, and an organic acid is preferable from the viewpoint of reducing the influence of the acid on workers and devices. Citric acid is preferred from the viewpoint of removal of
Although ozone gas is used as the oxidizing agent, the present embodiment is not limited to this example, and another oxidizing agent may be used, and a liquid oxidizing agent even if it is not a gaseous oxidizing agent Or, a solid oxidizing agent may be melted in a liquid. Examples of the oxidizing agent include chlorine dioxide, peracetic acid, sodium hypochlorite and hydrogen peroxide.

The fourth separation device 20 recovers pulp fibers by separating the pulp fibers from the treatment liquid (mixed liquid 99) containing the pulp fibers treated by the oxidant treatment device 19 with a screen having a plurality of openings. And recycled pulp fibers are produced.
Examples of the fourth separation device 20 include a screen separator. However, the opening of the screen (sieve) is not particularly limited, and examples thereof include slits, round holes, square holes, and meshes. Here, slits are used. The size (width) of the slit is such that pulp fibers can not easily pass through. The size of the slit is, for example, 0.2 to 0.8 mm in width. In the case of a round hole, the size of the round hole is, for example, 0.2 to 0.8 mm in diameter.

The system 1 preferably includes an ozone treatment device 22, a pH adjustment device 23, and a water storage tank 24. These devices are devices for regenerating and reusing the acidic aqueous solution used in the system 1. Reuse of the acidic aqueous solution can reduce the cost of the acidic aqueous solution. The ozone treatment device 22 sterilizes the superabsorbent polymer separated by the second separator 17 and the acidic aqueous solution 101 after the superabsorbent polymer is further separated from the acidic aqueous solution with an ozone-containing aqueous solution. The pH adjusting device 23 adjusts the pH of the acidic aqueous solution 102 sterilized with the ozone-containing aqueous solution to generate a regenerated acidic aqueous solution 103. The water storage tank 24 stores the surplus of the regenerated acidic aqueous solution 103.

Next, a method of recovering pulp fibers from a used absorbent article will be described. This method is a method of recovering pulp fibers (preferably further super absorbent polymer) from used absorbent articles and thus producing recycled pulp fibers (preferably further recycled super absorbent polymer). FIG. 6 is a flowchart showing an example of a method according to the present embodiment. This method comprises a drilling step S11 and a crushing step S12, preferably a first separation step S13, a first dust removal step S14, a second dust removal step S15, a third dust removal step S16, and a third dust removal step S16. A second separation step S17, a third separation step S18, an oxidant treatment step S19, and a fourth separation step S20 are provided. The details will be described below.

The punching process S11 is performed by the bag opening apparatus 11. The collection bag A in which the used absorbent article is sealed is put into the solution tank V storing the acidic aqueous solution B, and a hole is made in the surface of the collection bag A in contact with the acidic aqueous solution B. The acidic aqueous solution B is enclosed and sealed around the collection bag A so that the dirt, fungus and odor of the used absorbent article in the collection bag A are not released to the outside when the collection bag A is punctured. Do. When the acidic aqueous solution intrudes into the collection bag A from the hole, the gas in the collection bag A escapes to the outside of the collection bag A, and the specific gravity of the collection bag A becomes heavier than the acidic aqueous solution B. Settle down. In addition, the acidic aqueous solution B inactivates the superabsorbent polymer in the used absorbent article in the collection bag A.

The superabsorbent polymer in the used absorbent article is inactivated and its ability to absorb water is reduced, so that the superabsorbent polymer is dewatered and the particle size is reduced, making it easy to handle in each subsequent step Process efficiency is improved. The reason for using an acidic aqueous solution, ie, an aqueous solution of an inorganic acid and an organic acid, as the inactivating aqueous solution is that ash does not remain in the pulp fiber as compared with an aqueous solution such as lime or calcium chloride. It is because it is easy to adjust the particle size and the size of specific gravity by pH. The pH of the acidic aqueous solution is preferably 1.0 or more and 4.0 or less, and more preferably 1.2 or more and 2.5 or less. If the pH is too high, the water absorbing ability of the superabsorbent polymer can not be sufficiently reduced. In addition, the sterilization capacity may be reduced. If the pH is too low, equipment may be corroded, and a large amount of alkali chemicals are required for neutralization treatment during wastewater treatment. In particular, in order to separate the pulp fibers and the superabsorbent polymer from the other materials, it is preferable that the size and specific gravity of the pulp fibers be relatively close to the size and specific gravity of the superabsorbent polymer. Therefore, by setting the pH of the acidic aqueous solution to 1.0 or more and 4.0 or less, the superabsorbent polymer can be made smaller by inactivation, whereby the size and specific gravity of pulp fiber and superabsorbent property The size and specific gravity of the polymers can be relatively close to one another. Examples of the organic acid include citric acid, tartaric acid, glycolic acid, malic acid, succinic acid, acetic acid, ascorbic acid and the like, with hydroxycarbonate organic acids such as citric acid, tartaric acid and gluconic acid being particularly preferable. . Due to the chelating effect of citric acid, metal ions and the like in the excrement can be trapped and removed, and a high dirt component removing effect can be expected from the washing effect of citric acid. On the other hand, examples of the inorganic acid include sulfuric acid, hydrochloric acid and nitric acid, but sulfuric acid is preferable from the viewpoint of containing no chlorine and cost. Since the pH changes depending on the water temperature, the pH in the present invention refers to the pH measured at an aqueous solution temperature of 20 ° C. The organic acid concentration of the organic acid aqueous solution is not particularly limited, but when the organic acid is citric acid, 0.5 mass% or more and 4 mass% or less is preferable. The inorganic acid concentration of the inorganic acid aqueous solution is not particularly limited, but when the inorganic acid is sulfuric acid, 0.1 mass% or more and 0.5 mass% or less is preferable.

For example, in the bag-breaking apparatus 11 of FIG. 2, first, the swirling flow is generated in the acidic aqueous solution B by rotation of the stirring blade 33 around the rotation shaft (support shaft 32), and the collection bag A is physically forced. It is drawn toward the bottom of the aqueous solution B (solution tank V). Then, the collection bag A moved to the bottom portion contacts the tear-off blade 41 by the rotation of the tear-off blade 41 around the rotation axis (supporting shaft 42), and a hole is made. It should be noted that if the tearing blade 41 can move up and down in the solution tank V, the tearing blade 41 does not draw in the direction of the bottom of the acidic aqueous solution B (solution tank V) by the swirling flow. It may move upward and make a hole in the collection bag A.
Further, for example, in the bag-breaking apparatus 11 of FIG. 3, first, the collection bags A are pushed one after another along the spiral of the plate-like member 37 from above the feeding portion 30a to move along the spiral over the plate-like member 37 It is physically and forcibly fed into the solution tank Va filled with the acidic aqueous solution B from the lower side of the feeding unit 30a. Then, the collection bag A that has moved to the solution tank Va contacts the projection 44 and is punctured by the rotation of the rotating rotor 41a around the rotation axis (supporting shaft 42).

The crushing step S12 is performed by the crushing device 12. Acidic aqueous solution B containing collection bag A which a hole opened and sank under the surface of acidic aqueous solution B, ie, a used absorbent article in collection bag A, while mixed solution 91 is discharged from solution tank V, collection bag A The whole is crushed in the acidic aqueous solution B.
For example, in the crushing apparatus 12 of FIG. 2, first, use in the collection bag A delivered together with the acidic aqueous solution B from the solution tank V mainly by gravity by opening the valve (not shown) of the piping 61 by the crushing part 60 The finished absorbent article is crushed together with the collection bag A in the acidic aqueous solution B (in-liquid crushing step). At this time, in the crushing unit 60 of FIG. 4, the rotary blade 74 and the spacer 73 rotate toward the inside of the crushing unit 60 around one rotation shaft 72 and the inside of the crushing unit 60 around the other rotation shaft 72. The mixed solution 91 is supplied between the rotary blade 74 and the spacer 73 which rotate toward, and the collection bag A is crushed together with the bag. Then, in the crushing apparatus 12 of FIG. 2, the acidic aqueous solution B (mixed liquid 92) containing the crushed material obtained in the crushing part 60 (in-liquid crushing step) is drawn out from the crushing part 60 by the pump 63 (extraction step) It is sent to the next process.

Here, in the crushing step S12, as described later, it has a step of crushing the used absorbent article together with the collection bag A so that the average value of the size of the crushed material is 50 mm or more and 100 mm or less. Is preferred. In other words, the two-shaft crusher of the crusher 60 mainly uses the difference a in the radius between the rotary blade 74 and the spacer 73 and the rotary blade 74 so that the average value of the size of the crushed material is 50 mm or more and 100 mm or less. Preferably, it is adjusted by the axial thickness b.

As the absorbent article, a length of about 150 to 1000 mm and a width of 100 mm to 1000 mm are assumed. By crushing so that the average value of the magnitude | size of a crushing thing will be 50 mm or more and 100 mm or less, a cut can be reliably put in the back sheet and / or top sheet of each used absorbent article. As a result, since it is possible to take out almost all the pulp fibers from the cuts in each used absorbent article, the recovery rate of the pulp fibers (total amount of pulp fibers regenerated / the pulp fibers of the used absorbent articles supplied Total amount). When the average size is less than 50 mm, materials other than pulp fiber (example: film (material of collection bag A, back sheet, etc.), non-woven fabric (surface sheet, etc.), elastic body (leakage barrier rubber, etc.) ) Is cut too small to make it difficult to separate the material and the pulp fibers in the subsequent step. As a result, foreign matter (other materials) mixed in the pulp fiber to be regenerated increases, and the recovery rate of the pulp fiber decreases. On the other hand, when the average value of the size is larger than 100 mm, it becomes difficult to cut the used absorbent article. As a result, the size of the crushed material is large and bulky, and the amount (processed amount) of the crushed material (disposable diaper) that can be processed by the first separation device 13 in the first separation step S13 decreases, and the processing efficiency is improved. descend. Furthermore, the used absorbent article which can not take out pulp fiber will arise, and the recovery rate of pulp fiber falls. Specific examples will be described later.

The first separation step S13 is performed by the first separation device 13. The mixed liquid 92 containing the crushed material obtained by the crushing device 12 and the acidic aqueous solution is stirred to remove dirt from the crushed material, and the mixed liquid 92 is a pulp fiber, a super absorbent polymer, and an acid. It is separated into aqueous solution and other materials. At this time, an acidic aqueous solution may be separately added in order to enhance the cleaning effect and / or adjust the pH. As a result, the pulp fiber, the superabsorbent polymer and the acidic aqueous solution (including a part, other materials, etc.) in the mixed solution 92 are separated through the through holes and sent out from the first separation device 13 (Mixed solution 93). On the other hand, the pulp fiber of the liquid mixture 92, the superabsorbent polymer, and other materials except the acidic aqueous solution can not pass through the through holes and remain in the first separation device 13 or are delivered by another route. However, some of the other materials are delivered together with the liquid mixture 93 without being completely separated. Here, when a washing machine is used as the first separation device 13, the size of the through hole of the washing tub functioning as a sieve may be 5 mm to 20 mm in the case of a round hole, and holes of other shapes may be used. In the case, the size of the area substantially the same as that of the round hole may be mentioned.

The present method (system) includes at least the drilling step S11 and the crushing step S12 in the crushing process (punching step S11, crushing step S12, first separation step S13) for crushing the used absorbent article as described above. Have.

When an acidic aqueous solution is not used as the inactivating aqueous solution between the drilling step S11 and the first separation step S13, the pulp aqueous solution is added to the acidic aqueous solution from the first dust removing step S14 and supplied to the first dust removing step S14. And it is preferable to make the inactivating aqueous solution containing a super absorbent polymer substantially into an acidic aqueous solution. In that case, the specific gravity and size of the superabsorbent polymer can be easily adjusted by pH.

The first dust removing step S14 is executed by the first dust removing device 14. The acidic aqueous solution containing the pulp fibers and super absorbent polymer delivered from the first separation device 13, ie, the mixed liquid 93, contains the pulp fibers and super absorbent polymer by the screen while the pH is maintained within the predetermined range. It is separated into acidic aqueous solution and other materials (foreign matter). As a result, the pulp fiber, the superabsorbent polymer, and the acidic aqueous solution (including a part, other materials, etc.) in the mixed liquid 93 are separated through the screen and delivered from the first dust removing device 14 ( Liquid mixture 94). On the other hand, the pulp fiber of the liquid mixture 93, the superabsorbent polymer, and other materials except for the acidic aqueous solution can not pass through the screen and remain in the first dust remover 14, or are delivered by another route. However, some of the other materials are delivered together with the mixture 94 without being completely separated.

Incidentally, the pH of the acidic aqueous solution is adjusted so that the difference between the specific gravity and size of the superabsorbent polymer and the specific gravity and size of the pulp fiber respectively falls within a predetermined range at least by the first dust removal step S14. preferable. The predetermined range is, for example, 0.2 to 5 times that of the other. In this case, in the steps prior to the first dust removal step S14, the differences between the specific gravity and size of the pulp fiber and the superabsorbent polymer, and the specific gravity and size of the superabsorbent polymer, and the specific gravity and size of the pulp fiber are within predetermined ranges. It can be viewed as an inactivation step of inactivating the superabsorbent polymer by mixing it with a pH-adjusted acidic aqueous solution.

Moreover, as a density | concentration which united the pulp fiber and super absorbent polymer in the acidic solution in 1st dust removal process S14, 0.1 mass% or more and 10 mass% or less are mentioned, for example, 0.1 mass% or more 5 mass% or less is preferable. The ratio of pulp fiber to super absorbent polymer in the acidic solution is, for example, 50 to 90% by mass: 50 to 10% by mass.

The second dust removing step S15 is executed by the second dust removing device 15, and the acidic aqueous solution containing the pulp fiber and the superabsorbent polymer delivered from the first dust removing device 14, that is, the mixed solution 94 has a pH within a predetermined range. While being maintained, the screen separates the acidic aqueous solution containing pulp fibers and super absorbent polymer into other materials (foreign matter). As a result, the pulp fiber, the superabsorbent polymer and the acidic aqueous solution (including a part, other materials, etc.) of the mixed solution 94 pass through the screen and are separated, and are delivered from the second dust remover 15 (mixture Liquid 95). On the other hand, the pulp fiber of the liquid mixture 94, the superabsorbent polymer, and other materials except the acidic aqueous solution can not pass through the screen and remain in the second dust remover 15, or are delivered by another route. However, some of the other materials are delivered together with the mixture 95 without separation. The pH of the acidic aqueous solution is adjusted such that the difference between the specific gravity and the size of the superabsorbent polymer and the specific gravity and the size of the pulp fiber is within a predetermined range.

The third dust removing step S16 is executed by the third dust removing device 16, and the acidic aqueous solution containing the pulp fiber and the superabsorbent polymer delivered from the second dust removing device 15, that is, the mixed solution 95 has a pH within a predetermined range. While maintained, it is centrifuged in an inverted conical housing to separate into pulp fibers and superabsorbent polymer in acidic aqueous solution and other materials (foreign matter). As a result, the pulp fiber, the superabsorbent polymer and the acidic aqueous solution in the mixed solution 95 are delivered from the upper part of the third dust remover 16 (cyclone separator) (mixed solution 96). On the other hand, other heavy materials such as pulp fiber, super absorbent polymer, and metal other than the acidic aqueous solution in the mixed solution 95 are delivered from the lower part of the third dust remover 16 (cyclone separator). The pH of the acidic aqueous solution is adjusted so that the difference between the specific gravity and the size of the superabsorbent polymer and the specific gravity and the size of the pulp fiber is the same within a predetermined range.

The present method (system) is a dust removing process (first dust removing step S14 (first dust removing device 14) to third dust removing step S16 (third dust removing device 16) for removing foreign substances (other materials) as described above. At least a second dust removing step S15 (second dust removing device 15) and a third dust removing step S16 (third dust removing device 16)). Therefore, pulp fibers and superabsorbent polymers are easily separated in size from mainly resin materials among other materials of used absorbent articles other than pulp fibers and superabsorbent polymers (second dust removing step) S15 (second dust remover 15)) can be easily separated from the other material having a large specific gravity, such as a metal material, by specific gravity (third dust remover step S16 (third dust remover 16)). After that, by separating the pulp fibers and the superabsorbent polymer from each other (second and third separation steps S17 and S18 (second and third separation devices 17 and 18), pulp fibers and used absorbent articles are used. It is possible to recover the super absorbent polymer, which can reduce the number of processes for separating the pulp fiber and super absorbent polymer from the other materials, that is, to increase the efficiency of the process for separating the super absorbent polymer and the pulp fiber. Can.

The second separation step S17 is performed by the second separation device 17. The acidic aqueous solution containing the pulp fibers and super absorbent polymer delivered from the third dust collector 16, ie, the mixed liquid 96, is separated by the drum screen into pulp fibers in the acidic aqueous solution and super absorbent polymer in the acidic aqueous solution Be done. As a result, the acidic aqueous solution containing the superabsorbent polymer is separated from the mixed solution 96 through the drum screen and delivered from the second separation device 17. On the other hand, the acidic aqueous solution containing pulp fibers in the mixed solution 96 can not pass through the drum screen, and is sent out from the second separation device 17 through another route (mixed solution 97). After that, the superabsorbent polymer can be separated from the separated superabsorbent polymer and the acidic aqueous solution by a screen separator or the like. Therefore, the above steps can be said to be the steps of separating and recovering the superabsorbent polymer, and thus the steps of producing a recycled superabsorbent polymer.

The third separation step S18 is performed by the third separation device 18. Pulp fibers, a non-separable remaining super absorbent polymer and an acidic aqueous solution, ie, mixed liquid 97, delivered from the second separation device 17 are mixed with a solid containing pulp fibers and super absorbent polymer by a drum screen, And the liquid containing the acidic aqueous solution. And with the separation, the superabsorbent polymer in the solid is pressurized and crushed. Crushing is exemplified by crushing the gel superabsorbent polymer at a pressure higher than the gel strength. As a result, the acidic aqueous solution containing the superabsorbent polymer is separated from the mixed solution 97 through the drum screen and delivered from the third separation device 18. On the other hand, the pulp fiber in which the highly water-absorptive polymer of the mixed liquid 97 is crushed can not be added to the drum screen, and is delivered to the outside of the third separation device 18 from the gap of the lid of the drum screen 98). The pressure applied to the lid is preferably, for example, 0.02 MPa or more and 0.5 MPa or less. If the pressure is less than 0.02 MPa, it becomes difficult to crush the superabsorbent polymer and the time for oxidizing agent treatment can not be shortened so much, and if the pressure is larger than 0.5 MPa, the superabsorbent polymer can be crushed sufficiently. It may damage pulp fibers.

The oxidizing agent processing step S19 is performed by the oxidizing agent processing device 19. The pulp fibers in solid and the crushed superabsorbent polymer delivered from the third separation device 18 are treated with an aqueous solution containing an oxidizing agent. Thereby, the superabsorbent polymer is oxidatively decomposed and removed from the pulp fiber. As a result, the superabsorbent polymer adhering to the pulp fibers of mixture 98 (example: remaining on the surface of pulp fibers) is oxidized and decomposed by an aqueous solution (treatment liquid) containing an oxidizing agent (example: ozone) to obtain an aqueous solution It is removed from the pulp fibers by converting it to soluble low molecular weight organics. Here, the state in which the superabsorbent polymer is oxidatively decomposed to change to a low molecular weight organic substance soluble in an aqueous solution means that the superabsorbent polymer passes through a 2 mm screen. As a result, impurities such as superabsorbent polymers contained in the pulp fibers can be removed, and pulp fibers with high purity can be generated, and sterilization, bleaching and deodorization of pulp fibers can be performed by oxidizing agent treatment.
For example, in the oxidizing agent processing unit 19, the mixture 98 is introduced from the upper portion of the processing tank and settles from the upper portion to the lower portion of the processing solution, that is, the aqueous solution containing the oxidizing agent. On the other hand, the ozone-containing gas is continuously released from the nozzles in the treatment tank into the treatment liquid in the form of fine bubbles (eg, micro bubbles or nano bubbles). That is, the ozone-containing gas rises from the bottom to the top of the treatment liquid. In the processing solution, the settling pulp fibers and the rising ozone-containing gas collide with each other while advancing in the opposite direction. Then, the ozone-containing gas adheres to the surface of the pulp fiber so as to wrap the pulp fiber. At that time, ozone in the ozone-containing gas reacts with the superabsorbent polymer in the pulp fiber to oxidatively decompose the superabsorbent polymer and dissolve it in the treatment liquid. Thereby, the superabsorbent polymer contained in the pulp fibers of the mixture 98 is oxidatively decomposed to be removed from the pulp fibers.

The fourth separation step S20 is executed by the fourth separation device 20, and the treatment liquid containing pulp fibers processed by the oxidant treatment device 19, that is, the mixed liquid 99 passes through the screen having a plurality of slits, Pulp fibers and the treatment liquid are separated from the liquid mixture 99. As a result, the treatment liquid 104 is separated from the liquid mixture 99 through the screen and delivered from the fourth separation device 20. The separated processing liquid 104, ie, the oxidizing agent processing liquid, may be returned to the oxidizing agent processing device 19 for reuse. The cost of the oxidant treatment solution can be reduced. On the other hand, pulp fibers in the mixed solution 99 can not pass through the screen and remain in the fourth separation device 20 or are delivered by another route. The above process can be said to be a process of separating and recovering pulp fibers, and thus a process of producing recycled pulp fibers.

This method (system) includes at least the fourth separation process (the second separation step S17 (second separation device 17) to the fourth separation step S20 (fourth separation device 20)) for collecting pulp fibers and the like as described above. A third separation step S18 (third separation device 18) and an oxidant treatment step S19 (oxidant treatment device 19) are provided. Therefore, the surface area of the superabsorbent polymer can be greatly expanded by crushing the substantially spherical or massive superabsorbent polymer, and the exposed part can be increased by, for example, exposing the inner part of the superabsorbent polymer to the front side. it can. Therefore, in the oxidizing agent treatment step S19 (oxidizing agent treatment device 19), in the case of a massive or substantially spherical superabsorbent polymer, the inner portion of the superabsorbent polymer which was difficult to contact with the oxidant is contacted with the oxidant. For example, the contact area with the oxidizing agent in the superabsorbent polymer can be increased. As a result, the oxidative decomposition of the superabsorbent polymer can be advanced more efficiently, and the time of oxidant treatment can be shortened. Thus, the efficiency of the process of removing the superabsorbent polymer from the pulp fibers can be increased.

The crushing process is preferably performed in a batch process. The collection bag A and the acidic aqueous solution B for one batch in the volume tank V (Va) are both drawn out from the solution tank V (Va) via the crushing unit 60 by the pump 63. At this time, the used absorbent article is crushed along with the collection bag A in the crushing section 60 along the way. In that case, the in-liquid crushing step and the withdrawal step are performed simultaneously and simultaneously in a single burst.

In addition, this method preferably includes an ozone treatment step S22 and a pH adjustment step S23. These steps are steps for regenerating and reusing the acidic aqueous solution used in this method. Reuse of the acidic aqueous solution can reduce the cost of the acidic aqueous solution. In the ozone treatment step S22, the superabsorbent polymer separated in the second separation step S17 and the acidic aqueous solution 101 after the superabsorbent polymer are further separated from the acidic aqueous solution are sterilized with an ozone-containing aqueous solution. In the pH adjustment step S23, the pH of the acidic aqueous solution 102 sterilized with the ozone-containing aqueous solution is adjusted to generate a regenerated acidic aqueous solution 103. The acidic aqueous solution 103 may be, for example, supplied to the crushing apparatus 11 and may be supplied to another process (apparatus) that requires the acidic aqueous solution as needed. The surplus of the acidic aqueous solution 103 is stored in the water storage tank 24.

In the method of recovering pulp fibers from a used absorbent article containing pulp fibers and a superabsorbent polymer as described above, a crushing process of crushing the used absorbent article (piercing step S11 (bag opening apparatus 11) to 1 In the separation step S13 (first separation device 13), at least the hole making step S11 (bag opening device 11) and the crushing step S12 (crushing device 12) are provided. Then, in the hole making step S11 (bag opening apparatus 11), the inactivation aqueous solution (example: acidic aqueous solution) is introduced from the hole into the collection bag by making a hole in the collection bag, and used absorbent articles are used. While inactivating the contained super absorbent polymer with the inactivating aqueous solution, the collection bag is substantially sunk below the surface of the inactivating aqueous solution. Next, in the crushing step S12 (shredding device 12), the used absorbent articles are collected together with the inactivated aqueous solution in the inactivated aqueous solution while discharging from the solution tank together with the inactivated aqueous solution. Crush. Therefore, since the used absorbent articles in the collection bag are crushed together with the collection bag in the inactivated water solution, the inactivated water solution mixes with dirt and fungi, and an odor is generated, at least until crushing is started. There is almost nothing. Then, when the used absorbent article is crushed, the inactivated aqueous solution may be mixed with dirt or fungi, or odor may be generated, but the inactivated aqueous solution mixed with dirt or fungi is destroyed at almost the same time as the disruption. The solution is sent out from the solution tank, so that the solution tank can be washed away with almost no dirt or fungus remaining. In addition, since the odor can be sealed with the inactivating aqueous solution, the generation of the odor can be suppressed to a low level. Thus, when the used absorbent article is crushed, it is possible to suppress the scattering of dirt and fungi and the release of the odor associated with the dirt. That is, the used absorbent article can be crushed hygienically and safely, and the cost of hygienic management in operation and maintenance can be suppressed.

As a preferable mode in the embodiment, the step of drilling holes in the collection bag in the step of drilling S11 and the step of crushing the used absorbent article together with the collection bag in the crushing step S12 may be performed at different positions. .
In this method, the steps of piercing the collection bag (bag-breaking device 11) and crushing the used absorbent article together with the collection bag (fragmenting device 12) are performed at different places or positions (devices) different from each other. . Therefore, after the inactivating aqueous solution is introduced into the collecting bag through the hole and the collecting bag is surely submerged under the surface of the inactivating aqueous solution, crushing can be performed at another place or position. Therefore, at the time of crushing, a part of the collection bag is exposed on the water surface of the inactivating aqueous solution, and the opening (tear) of the hole is exposed on the water surface of the inactivating aqueous solution. It is possible to suppress the situation of scattering or releasing the odor associated with the contamination.

As a preferable mode in the embodiment, the crushing step S12 (crushing device 12) includes a submerged crushing step (crushing portion 60) of crushing the used absorbent article in the collection bag together with the collection bag in the inactivated aqueous solution; And the drawing process (pump 63) which pulls out the crushing thing obtained at the in-liquid crushing process (crushing part 60) from the in-liquid crushing process (crushing part 60) with the inactivating aqueous solution.
In this method, the mixed solution 92 of the crushed material and the inactivating aqueous solution is actively pulled out from the in-liquid crushing step (crushing unit 60), whereby the in-liquid crushing step (crushing unit 60) is performed. Contamination of the equipment involved in the above can be removed (washed away) by the inactivating aqueous solution. Thereby, the hygienic state in the crushing process (crushing device 12) can be maintained well.
Here, in the vertical direction, it is preferable that the crushing portion be present below as compared with the solution tank. As a result, the mixed solution 92 can be positively withdrawn from the in-liquid crushing step (crushing portion 60) also using gravity. Thereby, along with the movement of the mixed liquid 92, it is possible to remove (flush off) dirt of equipment involved in the in-liquid crushing step (crushing portion 60) by the inactivating aqueous solution.

As a preferable mode in the embodiment, the crushing step S12 (crushing device 12) crushes the used absorbent article together with the collection bag so that the average value of the size of the crushed material is 50 mm or more and 100 mm or less. May be included.
In this method, in the crushing step S12 (crushing device 12), the crushing device 12 is adjusted so that the average value of the sizes of crushed materials is 50 mm or more and 100 mm or less. In that case, since the back sheet and / or the top sheet of each used absorbent article can be reliably cut, it is possible to take out pulp fibers substantially without leaving the cut in each used absorbent article. Thereby, the recovery rate of pulp fiber and super absorbent polymer can be increased. However, when the average value of the size is less than 50 mm, other materials (example: film, non-woven fabric, elastic body, etc.) other than pulp fiber and super absorbent polymer are cut too small, and pulp fiber and super absorbent polymer It becomes difficult to separate from. As a result, the pulp fiber to be regenerated and other materials mixed in the superabsorbent polymer are increased, and the recovery rate of the pulp fiber is reduced. On the other hand, when the average value of the size is larger than 100 mm, it becomes difficult to cut the used absorbent article. As a result, the used absorbent article which can not take out a pulp fiber or a super absorbent polymer will arise, and the recovery of a pulp fiber or a super absorbent polymer will fall.

As a preferable mode in the embodiment, the step of crushing the used absorbent article in the inactivating aqueous solution together with the collection bag in the crushing step S12 (crushing device 12) may be performed by a biaxial crusher (crushing (crushing) Section 60 may include a twin screw crusher).
In the method, the step of crushing the used absorbent article is performed using a twin-screw crusher (crushing unit 60 includes a twin-screw crusher). The twin screw crusher is exemplified as a twin screw rotary crusher, a twin screw differential crusher, and a twin screw shear crusher. Therefore, the size of the crushed material can be approximately aligned within a predetermined range. As a result, the crushed material becomes too small, foreign matter is mixed in the pulp fiber, or the crushed material becomes too large, and a used absorbent article from which the pulp fiber can not be taken out is generated, and the recovery rate of the pulp fiber is increased. It is possible to control the situation of falling.

As another embodiment, the step of forming a hole on the surface of the collection bag in contact with the inactivating aqueous solution in the forming step S11 (the bag-breaking device 11) (the hole forming portion 50) is a solution tank while rotating around the rotation axis. It may be implemented by a projection (the tearing blade 41 of the tearing portion 40) which can move up and down in V.
In this method, a hole is made in the collection bag with a projection (the tearing blade 41) moving up and down in the solution tank while rotating around the rotation axis. Therefore, even if the collection bag is not allowed to settle in the inactivating aqueous solution, the collection bag can be reliably punctured by, for example, moving the projection upward of the solution tank and contacting the collection bag. By drilling the holes and settling the collection bag in the inactivated aqueous solution, the collection bag can be reliably submerged in the acidic solution in a short time, reducing the processing time and increasing the processing efficiency.

As a preferred aspect or another embodiment of the embodiment, a step of forming a hole in the surface of the collection bag in contact with the inactivating aqueous solution in the hole forming step S11 (the bag opening apparatus 11) (the hole forming portion 50 or the hole forming portion 50a ), The collection bag is sent from the upper part of the solution tank Va into the inactivating aqueous solution, disposed at the lower part of the solution tank Va, and the projections rotating around the rotation axis (the tearing blade 41 of the tearing portion 40, the bag) It may be carried out by bringing the protrusion 44) of the rotating rotor 41a of the portion 40a into contact.
In this method, the collection bag is fed into the inactivating aqueous solution, and the lower part of the solution tank Va (the bag-breaking blade 41 of the tear-off portion 40 and the protrusion 44 of the rotating rotor 41a of the tear-off portion 40a) Make a hole in Since the collection bag is sedimented in the inactivated aqueous solution and then punctured, it is possible to reliably prevent the spread of dirt and odor from the used absorbent articles in the collection bag to the outside. Thereby, used absorbent articles can be crushed more hygienically and safely.

In a preferred aspect of the embodiment, the inactivated aqueous solution is an acidic aqueous solution.
In this method, since the inactivating aqueous solution is an acidic aqueous solution, the superabsorbent polymer in the used absorbent article can be reliably dewatered and inactivated. In particular, when crushing is performed in an acidic aqueous solution, alkaline volatile components derived from excrement such as urine do not volatilize and remain in the acidic aqueous solution, so that generation of odor due to alkaline gas such as ammonia can be suppressed. As a result, in the crushing step S12 (crushing device 12), the used absorbent article does not swell significantly, so crushing can be easily performed, and processing efficiency can be enhanced.

In a preferred aspect of the embodiment, the acidic aqueous solution comprises citric acid.
In this method, since the acidic aqueous solution contains citric acid (example: concentration 0.5 to 2.0% by mass), the superabsorbent polymer in the used absorbent article can be dehydrated and inactivated as well as the acid. There is almost no adverse effect on workers due to and corrosion of equipment of each process by acid can be suppressed.

Second Embodiment
The second embodiment will be described. In the following, differences from the first embodiment will be mainly described. However, also in the present embodiment, the case of using an acidic aqueous solution as the inactivating aqueous solution will be described as an example.

A system 1 used in a method of recovering pulp fibers from used absorbent articles is described. FIG. 6 is a block diagram showing an example of a system 1 according to the present embodiment. The system 1 according to the present embodiment includes a container (not shown), a crushing apparatus 12, and a first separation apparatus 13. Preferably, a first dust removal apparatus 14 and a second dust removal apparatus 15 are provided. A third dust remover 16, a second separating device 17, a third separating device 18, an oxidizing agent processing device 19, and a fourth separating device 20 are provided. The details will be described below.

In the present embodiment, the crush and separation apparatus 10 is configured by integrating a container (not shown), the crushing apparatus 12 and the first separation apparatus 13. That is, the system 1 is provided with a crushing and separating apparatus 10. Here, the container is a container for containing the collection bag A in which the used absorbent article is sealed. The crushing apparatus 12 is in communication with the container, and the used absorbent articles in the collection bag A are crushed together with the collection bag A in the acidic aqueous solution B while the collection bag A in the container is transferred. The first separation device 13 separates the pulp fiber, the superabsorbent polymer and the inactivated aqueous solution from the crushed material and the acidic aqueous solution B obtained by the crushing device 12.

FIG. 7 is a schematic view showing a configuration example of the crushing and separating apparatus 10 (container + crushing apparatus 12 + first separating apparatus 13) of FIG. The container 65 is attached to the upper part of the crusher 12 and is released at the top, or has an open / close lid, and the collection bag A can be introduced into the inside from the top. In addition, the container 65 has a pipe 66 provided with a valve (not shown) joined to the side, and the acid aqueous solution B (or regenerated acidic aqueous solution 103 may be supplied) may be supplied from the pipe 66. Further, the lower part of the container 65 is in communication with the upper part of the crushing apparatus 12, and the acidic aqueous solution B supplied through the pipe 66 is transmitted to the inner wall surface to be supplied to the crushing apparatus 12 A may be supplied to the shredding device 12. The container 65 can also be viewed as an aspect in which the acidic aqueous solution B is not always stored in the solution tank V of the first embodiment.

An acidic aqueous solution B is stored in the crushing apparatus 12 so as to fill the inside of the crushing part 60 (see FIG. 4), for example, so as to cover the rotary shaft 72, the spacer 73 and the rotary blade 74 of the crushing part 60. There is. The liquid level is at least the position of the upper end of the rotary blade 74, and the position of the boundary between the container 65 and the crushing apparatus 12 is preferable. The height of the liquid level is measured, for example, by a liquid level gauge. When the collection bag A reaches the bottom of the container 65 and at least a part of the collection bag A is supplied into the acidic aqueous solution B in the crushing apparatus 12, the rotation of each of the pair of

rotating shafts

72, 72 of the crushing unit 60 The collection bag A is drawn into the crushing section 60 by the rotation of the blade 74 and the spacer 73. Thereby, the crusher 12 crushes the used absorbent articles in the collection bag A together with the collection bag A in the acidic aqueous solution B. The crushing apparatus 12 is connected by a pipe 62 to a first separating apparatus 13 disposed immediately below (the crushing part 60 of) the crushing apparatus 12. The crushing apparatus 12 sends out the crushed material obtained in the crushing part 60 together with the acidic aqueous solution B (mixed liquid 92), and supplies it to the first separation apparatus 13 through the pipe 62. In addition, the acidic aqueous solution B which runs short by delivery of the liquid mixture 92 may be replenished from the container 65, may be replenished from piping (not shown) directly connected to the crushing apparatus 12, or the first separation It may be supplied from the device 13.

The first separation device 13 is filled with the acidic aqueous solution B, and the mixture liquid 92 containing the crushed material obtained by the crushing device 12 and the acidic aqueous solution B is stirred, and the mixture liquid 92 to pulp fiber, high water absorption The polymer and the acidic aqueous solution are separated (mixed liquid 93) and sent to the first dust collector. Specifically, the first separation device 13 includes a container 80, an impeller 81, a screen plate 82, a side chamber 83, and a lower surface valve 84. The container 80 stores the mixed solution 92. The impeller 81 stirs the mixed solution 92 and guides it to the screen plate 82. The screen plate 82 is a screen having a plurality of openings. The size of the plurality of openings is such that the pulp fibers and the superabsorbent polymer in the crushed material in the mixed solution 92 can easily pass and the other materials can not easily pass. In the side chamber 83, an acidic aqueous solution (mixed liquid 93) containing pulp fibers and super absorbent polymer which has passed through the screen plate 82 is delivered. The lower surface valve 84 is opened when taking out other materials (foreign matter) which can not pass through the screen plate 82 accumulated in the container 80. Examples of the first separation device 13 include pack pulper (manufactured by Satomi Seisakusho Co., Ltd.).

Next, a method of recovering pulp fibers from a used absorbent article will be described. This method is a method of recovering pulp fibers (preferably further super absorbent polymer) from used absorbent articles and thus producing recycled pulp fibers (preferably further recycled super absorbent polymer). FIG. 8 is a flowchart showing an example of the method according to the present embodiment. This method comprises a crushing step S12 and a first separation step S13, preferably, a first dust removal step S14, a second dust removal step S15, a third dust removal step S16, and a second separation step S17. A third separation step S18, an oxidizing agent treatment step S19, and a fourth separation step S20 are provided. The details will be described below. The method according to the present embodiment can be regarded as the method according to the first embodiment excluding the hole making step S11.

The crushing step S12 is executed by the container 65 of the crushing and separating apparatus 10 and the crushing apparatus 12. The acidic aqueous solution B is supplied to the container 65 through the pipe 66 as necessary so as to set the height of the liquid surface of the acidic aqueous solution B of the crushing apparatus 12 to a predetermined height, and it travels along the inner wall surface. , While removing dirt on the inner wall surface.
The collection bag A is placed in the container 65, reaches the bottom of the container 65, and at least a portion of the collection bag A is supplied into the acidic aqueous solution B in the crushing apparatus 12. Then, the collection bag A is drawn into the acidic aqueous solution B in the crushing unit 60 by the rotation of the rotary blade 74 and the spacer 73 of the pair of

rotary shafts

72 and 72 of the crushing unit 60. As a result, the used absorbent articles in the collection bag A are crushed together with the collection bag A in the acidic aqueous solution B by the crushing unit 60. Also in the present embodiment, it is preferable that the average value of the size of the crushed material be 50 mm or more and 100 mm or less.
The mixed liquid 92 containing the crushed material and acidic aqueous solution B delivered from the fracturing unit 60 is delivered to the first separation device 13 disposed immediately below (the fracturing unit 60 of) the fracturing device 12 through the pipe 62. .

The first separation step S13 is performed by the first separation device 13 of the crushing and separation device 10. The container 80 of the first separation device 13 is filled with the acidic aqueous solution B by the supply of the acidic aqueous solution B (including the mixed solution 92) from the crushing device 12.
The mixed liquid 92 containing the crushed material and the acidic aqueous solution B is stirred by the impeller 81 in the container 80, and is guided toward the screen plate 82 while cleaning is performed to remove dirt from the crushed material. The mixed liquid 92 is separated by the screen plate 82 into pulp fibers, super absorbent polymer, acidic aqueous solution and other materials. That is, among the crushed material in the mixed solution 92, the pulp fiber and the superabsorbent polymer pass through the screen plate 82, reach the side chamber 83 and are separated, and other materials do not pass through the screen plate 82 so that the container 80 Remain inside. The pulp fiber, the superabsorbent polymer and the acidic aqueous solution B (mixed liquid 93) reaching the side chamber 83 are delivered to the first dust remover 14 through a pipe. However, some of the other materials are delivered together with the liquid mixture 93 without being completely separated. The size of the opening of the screen of the first separation device 13 may be 5 mm to 20 mm in the case of a circular opening, and the size of the circularly identical area may be mentioned in the case of an opening of any other shape. .

In the present system and method, at least after receiving the collection bag A in the container 65, the collection bag A is transferred to the crushing apparatus 12 provided separately from the container 65, and the acidic aqueous solution B (inactivation in the crushing apparatus 12) In the aqueous solution, while inactivating the superabsorbent polymer of the used absorbent article in the collection bag A, the used absorbent article is crushed together with the collection bag A. That is, when the used absorbent article is crushed, it is crushed in the acidic aqueous solution B in the crushing apparatus 12 separate from the container 65, and after the crushing, the acidic aqueous solution B and the crushed material are sent to the first separation device 13. Be transported. Therefore, even if dirt or a fungus is mixed in the acidic aqueous solution B or an odor is generated, the acidic aqueous solution B mixed with dirt or a fungus or a crushed material hardly reaches the container 65. Therefore, the container can be crushed with little dirt or fungus remaining. In addition, since the odor can be sealed with the acidic aqueous solution B, the generation of the odor can also be suppressed to a low level. In particular, when crushing in the acidic aqueous solution B, alkaline volatile components derived from excrement such as urine do not volatilize and stay in the acidic aqueous solution B, so that the generation of odor due to the alkaline gas such as ammonia can be suppressed. it can. Thus, when the used absorbent article is crushed, it is possible to suppress the scattering of dirt and fungi and the release of the odor associated with the dirt. That is, it is possible to hygienically and safely crush the used absorbent articles and to suppress the cost of hygiene management in work and maintenance.

Examples of the method for recovering pulp fibers from the above-mentioned used absorbent articles are described below.

In the present example, the drilling process S11, the crushing process S12, and the first separation process S13 of the method according to the first embodiment are performed on the absorbent article, and the crushing method and other materials ( The relationship with the amount of foreign substances) was investigated. Specifically, a disposable diaper for adults (unused) was used as the absorbent article. In the crushing step S12, disposable diapers in which the crushing apparatus 12 was adjusted so that the average values of the sizes of the crushed materials were 25 mm, 50 mm, and 100 mm, respectively, were taken as Examples 1 to 3. On the other hand, the disposable diaper which does not perform crushing process S12 was made into the comparative example.

The result of investigating the relationship between the crushing method and the mixing amount of other materials is shown in FIG. FIG. 9 is a graph showing the relationship between the size of the crushed material and the amount of treatment and the amount of foreign matter in the crushing step. The bar graph (the vertical axis is the left axis) indicates the throughput (kg) per batch, and indicates the amount of disposable diapers that can be processed by the first separation device 13 in the first separation step S13. The broken line graph (the vertical axis is the axis on the right) represents foreign matter other than the pulp fibers and the superabsorbent polymer contained in the mixed solution 93 (the aqueous solution containing the pulp fiber and the absorbent polymer after separation) after the first separation step S13. Indicates the percentage of (other materials).
When it is not crushed (comparative example), the disposable diaper is processed as it is in the first separation step S13. Therefore, as shown in the figure, the disposable diaper is large and bulky, and the front sheet and the back sheet are difficult to be separated, etc., so that it can be treated by the first separation device 13, that is, pulp fibers and super absorbent polymer can be taken out. The amount (throughput) of disposable diapers was small. However, since the material was not crushed, the size of each material was large, and the amount of foreign matter contained in the liquid mixture 93 after the first separation step S13 was small.
On the other hand, when crushed (Example), the disposable diaper becomes bulky, so the amount (processed amount) of disposable diapers that can be processed by the first separation device 13 increases. However, due to the crushing, the individual materials become smaller, and the amount of foreign matter contained in the mixed solution 93 after the first separation step S13 increases.
Therefore, it was found that crushing is better than uncrushing in terms of throughput. Furthermore, when the viewpoint of the amount of foreign substances is also considered, it was found that it is preferable to set the average value of the size of the crushed material to 50 mm or more and 100 mm or less.

The above embodiment describes the case where the component of the back sheet is a film and the component of the top sheet is a non-woven fabric. However, in the case where the constituent member of the back sheet is a non-woven fabric and the constituent member of the top sheet is a film, or when the constituent members of both the back sheet and the top sheet are films, the embodiments described above. Can be realized by the same method as the above, and the same function and effect can be exhibited.

The absorbent article of the present invention is not limited to the above-described embodiments, and does not deviate from the purpose and the spirit of the present invention, as long as technical contradiction does not occur. It is possible to appropriately combine or change the techniques of

A Collection bag V Solution tank S11 Drilling process S12 Crushing process S13 First separation process

Claims

A method of recovering pulp fibers from a used absorbent article comprising pulp fibers and a superabsorbent polymer, comprising:
Receiving a collection bag containing a used absorbent article in a container;
The used absorbent article in the collection bag is crushed in the inactivated aqueous solution together with the collection bag by the crushing apparatus while transferring the collection bag in the container to the crushing apparatus in communication with the container. Crushing process,
A separation step of separating a pulp fiber, a superabsorbent polymer and the inactivated aqueous solution from the crushed material obtained in the crushing step and the inactivated aqueous solution by a separating device;
How to provide.
The receiving step includes a step of placing the collecting bag in a solution tank as the container storing the inactivating aqueous solution, and drilling a hole in a surface of the collecting bag in contact with the inactivating aqueous solution,
In the crushing step, the holes are opened and the collection bag which is sunk below the surface of the inactivating aqueous solution is transferred from the solution tank to the crushing apparatus along with the inactivating aqueous solution, and the used absorption in the collection bag is absorbed. Crushing the functional articles together with the collection bag in the inactivated aqueous solution,
The method of claim 1.
The steps of drilling the collection bag in the drilling step and the step of crushing the used absorbent article together with the collection bag in the crushing step are performed at different positions.
The method of claim 2.
The crushing process is
An in-liquid crushing step of crushing the used absorbent article in the collection bag together with the collection bag in the inactivated aqueous solution supplied together with the collection bag;
Drawing out the crushed material obtained in the in-liquid crushing step from the in-liquid crushing step together with the inactivating aqueous solution;
including,
A method according to claim 2 or 3.
The step of drilling holes in the surface of the collection bag in contact with the inactivating aqueous solution in the drilling step is performed by a projection movable up and down in the solution tank while rotating around a rotation axis.
5. A method according to any one of claims 2-4.
The step of making a hole in the surface of the collection bag in contact with the inactivating aqueous solution in the hole making step comprises: feeding the collection bag into the inactivating aqueous solution from the upper part of the solution tank, and placing the collection bag in the lower part of the solution tank , Performed by contacting the protrusions rotating around the rotation axis,
5. A method according to any one of claims 2-4.
In the crushing step, the used absorbent article in the collecting bag is crushed in the inactivating aqueous solution together with the collecting bag while supplying the collecting bag into the inactivating aqueous solution in the crushing apparatus. Including the process,
The method of claim 1.
The separation step includes the step of directly receiving the crushed material and the inactivating aqueous solution in the separation device disposed immediately below the crushing device.
A method according to claim 1 or 7.
The crushing step includes the step of crushing the used absorbent article together with the collection bag so that the average size of the crushed material is 50 mm or more and 100 mm or less.
A method according to any one of the preceding claims.
The step of crushing the used absorbent article together with the collection bag in the inactivating aqueous solution in the crushing step is performed by a twin-screw crusher.
A method according to any one of the preceding claims.
The inactivated aqueous solution is an acidic aqueous solution,
A method according to any one of the preceding claims.
The acidic aqueous solution contains citric acid,
The method of claim 11.
A system for use in a method of recovering pulp fibers from a used absorbent article comprising pulp fibers and a superabsorbent polymer, comprising:
A container for containing a collection bag containing a used absorbent article;
A crushing device in communication with the container for crushing the used absorbent article in the collection bag together with the collection bag in an inactivated aqueous solution while the collection bag in the container is transferred;
A separation device for separating a pulp fiber, a superabsorbent polymer and the inactivated aqueous solution from the crushed material obtained by the crushing device and the inactivated aqueous solution;
System with
A solution tank as the container for storing the inactivated aqueous solution, and a hole formed in a surface of the solution tank, the surface being in contact with the inactivated aqueous solution in the collection bag when the collection bag is placed in the solution tank Further comprising: a bag-breaking device comprising:
The crushing apparatus transfers the collection bag, which has the hole opened and is sunk below the surface of the inactivating aqueous solution, from the solution tank to the crushing apparatus along with the inactivating aqueous solution, and the used absorption in the collection bag is absorbed. The sensitive articles together with the collection bag in the inactivated aqueous solution,
The system of claim 13.
The bag-breaking device and the shredding device are different devices from each other,
The system of claim 14.
The crushing device is
A crushing unit for crushing the used absorbent article in the collection bag in the inactivated aqueous solution supplied together with the collection bag and the collection bag;
A pump for drawing out the crushed material obtained in the crushing unit from the crushing unit together with the inactivating aqueous solution;
including,
A system according to claim 14 or 15.
In the bag-breaking apparatus, the hole-piercing portion includes a projection that can move up and down in the solution tank while rotating around a rotation axis.
A system according to any one of claims 14-16.
In the bag-removing apparatus, the perforations are:
A feeding unit for feeding the collection bag into the inactivated aqueous solution from the top of the solution tank;
A projection located at the bottom of the solution tank and rotating around a rotation axis to puncture the collection bag;
including,
A system according to any one of claims 14-16.
The crushing apparatus crushes the used absorbent article in the collection bag together with the collection bag in the inactivated water solution while the collection bag is supplied in the inactivated water solution in the crushing apparatus. ,
The system of claim 13.
The separation device is disposed immediately below the crushing device, and directly receives the crushed material and the inactivated aqueous solution from the crushing device.
20. A system according to claim 13 or 19.
The crushing apparatus crushes the used absorbent article together with the collection bag so that the average value of the size of the crushed material is 50 mm or more and 100 mm or less.
21. A system according to any one of claims 13 to 20.
The crusher includes a twin screw crusher,
22. A system according to any one of claims 13 to 21.
The inactivated aqueous solution is an acidic aqueous solution,
A system according to any one of claims 13-22.
The acidic aqueous solution contains citric acid,
The system of claim 23.