JP7228992B2 - METHOD OF COLLECTING COMPONENTS FROM USED ABSORBENT ARTICLES - Google Patents

Description

The present invention relates to a method of recovering components from used absorbent articles.

Techniques are known for recycling absorbent articles such as used disposable diapers. For example, Patent Literature 1 discloses a method for recycling used disposable diapers. This method comprises a step of breaking used paper diapers into pieces, a step of loading the broken paper diapers into a disassembling drum, and separating the loaded paper diapers into pulp components (including high-molecular polymers) by the disassembling drum. and separating the cracked pulp and non-pulp components. In the disassembly process, when a broken paper diaper is put into a disassembly drum filled with industrial water or seawater, the broken paper diaper is separated by a plurality of protrusions provided on the inner surface of the rotating disassembly drum. It breaks down into pulp and non-pulp components. The non-pulp component is reused as recycled resin or the like. As for the pulp component, the high-molecular weight polymer is crushed into fine particles by a crusher and discarded, and the pulp is recovered.

JP 2010-59586 A

In Patent Document 1, when a used paper diaper is decomposed into a pulp component and a non-pulp component, the paper diaper is previously broken into a plurality of small pieces (fragments). However, when the disposable diaper is broken into a plurality of small pieces, there is a risk that scraps and scraps may be generated at the broken portions of each small piece. In particular, used absorbent articles are discarded in a rolled-up or folded state with the surface sheet inside so that the excrement is not exposed on the front side and the odor is not diffused. is normal. Therefore, in a used absorbent article, the position and shape of the fractured portion are not constant, so there is a strong tendency to generate scraps and the like. Furthermore, when such a plurality of small pieces are disassembled by the disassembly drum, there is a risk that chips or the like may be generated from the fractured portions of each of the small pieces due to the impact caused by the rotation of the disassembly drum. Since the chips and the like are mixed with the waste water, it is difficult to recover the chips and the like. In addition, the smaller the size of each small piece, the more difficult it is to distinguish between the pulp component and the non-pulp component contained therein, which may make it difficult to separate the components. There is As a result, the recovery rate of a component such as a film in disposable diapers, ie, absorbent articles, is reduced.

A topsheet, a backsheet, and an absorbent body disposed between the topsheet and the backsheet, wherein at least one of the topsheet and the backsheet includes a film as a constituent member, and the absorbent body is a constituent member. A method for efficiently recovering the constituent members from the used absorbent article without breaking the used absorbent article when recycling the constituent members of the used absorbent article containing the absorbent material as offer.

The method of recovering the constituent members from the used absorbent article in the present invention is as follows. (1) comprising a topsheet, a backsheet, and an absorber disposed between the topsheet and the backsheet, wherein at least one of the topsheet and the backsheet includes a film as a constituent member; A method for recovering the constituent member from a used absorbent article in which the absorbent body contains an absorbent material as a constituent member, comprising: a pretreatment step of swelling the used absorbent article with water; a decomposition step of applying a physical impact to the used absorbent article to decompose the used absorbent article into at least the film and the absorbent material; and separating the decomposed film and the absorbent material. and a separating step.

In this method, in the pretreatment step, the used absorbent article is allowed to absorb water while maintaining its shape without breaking or the like, and without inactivating the superabsorbent polymer. Therefore, the used absorbent article can absorb water up to an amount close to the maximum absorption amount of the used absorbent article (example: 80% by mass or more of the maximum absorption amount). That is, the used absorbent article can be left in a highly swollen state with water. As a result, a very high internal pressure is created in the used absorbent article. The internal pressure allows the used absorbent article in the water to be flattened out from the rolled or folded state when discarded. At this time, the used absorbent article has expanded so much that some part of its surface is likely to burst.
Then, in the disassembly process, the used absorbent article in such an unfolded, flat state, which is about to burst at some point on its surface due to expansion, is subjected to a physical impact, e.g. , drop downwards and repeatedly collide with the base. As a result, the used absorbent article, which is about to burst at some point on the surface, is subjected to further impact, so that the surface is torn (peeled off) and the absorbent material inside the used absorbent article is torn. It will erupt (jump out) through the Thereby, the used absorbent article can be decomposed into at least the film and the absorbent material. At this time, the film generally maintains the same shape as the absorbent article, that is, the original shape, except for partial cracks and the like. Therefore, compared to the case where the film is broken into fragments before decomposition, the size, shape and mass of the film are clearly different from the size and shape of the absorbent material. It can be easily separated from the body material.
Thereby, the constituent member such as the film can be separated from the other constituent members while maintaining the shape as it is without breaking or the like. Therefore, constituent members such as films of absorbent articles can be efficiently recovered.

(2) the absorbent material comprises a superabsorbent polymer and pulp fibers, and the separating step comprises, prior to separating the film and the absorbent material, a step of deactivating the superabsorbent polymer; and a mixture containing the film, the pulp fibers, the deactivated superabsorbent polymer, and sewage discharged from the superabsorbent polymer by deactivation. The method according to (1) above, comprising the step of separating.
The superabsorbent polymer before deactivation is in a highly viscous state and cannot be said to be easily separated from the film. Therefore, in this method, the superabsorbent polymer is inactivated and the superabsorbent polymer is dehydrated before separating the film and the absorbent material. Thereby, the viscosity of the superabsorbent polymer can be reduced, so that the film can be easily separated from the superabsorbent polymer and thus from the mixture containing pulp fibers. Therefore, constituent members such as films of absorbent articles can be efficiently recovered.

In this method, (3) the disassembling step includes a step of putting the swollen used absorbent article into a horizontal rotating drum, and rotating the rotating drum to remove the used absorbent article from the It is lifted from the lower region in the vertical direction in the rotating drum to the upper upper region, and is lowered by gravity from the upper region to the lower region, and collides with the inner surface of the rotating drum in the lower region. The method according to (1) or (2) above, which includes the step of applying a physical impact to the used absorbent article by causing it to swell.
In this method, a horizontal rotating drum (example: a rotating drum of a washing tub of a horizontal washing machine) that rotates around a virtual rotation axis extending in the horizontal direction is used to apply a physical impact to the used absorbent article. can be given continuously and stably. That is, the used absorbent article placed on the inner surface of the rotating drum is lifted from the lower area to the upper area in the rotating drum by the rotation of the rotating drum, and is lowered from the upper area to the lower area by gravity. The used absorbent article can be impacted by colliding with the inner surface of the lower region. By continuing the rotation of the rotary drum, such a collision impact can be applied stably, continuously and easily. As a result, the joint portion between the top sheet (nonwoven fabric or film) and the back sheet (film) in the used absorbent article can be stably torn (peeled off), and the used absorbent article can be divided into the film and the absorbent material. can be reliably decomposed.

The method according to any one of (1) to (3) above, wherein (4) the pretreatment step includes a step of swelling the used absorbent article with the water at 70°C or higher and 98°C or lower. It may be the method described.
In this method, by setting the water temperature to 70° C. or higher, the adhesive that joins the film and other members can be softened by the heat of the water, and the bonding strength of the adhesive can be reduced. . Further, by setting the temperature of the water to 98° C. or less, the water is surely present as a liquid, so that the used absorbent article can surely absorb the water. As a result, it is possible to more reliably generate a state in which the surface is likely to burst due to expansion, and to generate a state in which the bonding strength of the adhesive is reduced. Therefore, in the disassembly process, the bonded portion between the top sheet (nonwoven fabric or film) and the back sheet (film) whose bonding strength is reduced is torn (peeled off), and the absorbent material inside the used absorbent article is torn. It can be made to erupt (jump out) to the outside. Thereby, the used absorbent article can be decomposed more reliably into at least the film and the absorbent material. In addition, sterilization is extremely important in reusing used absorbent articles. By setting the temperature of the water to 70° C. or higher, it is also possible to obtain the effect of sterilization (disinfection).

(5) The pretreatment step includes the step of allowing the used absorbent article to absorb the water in an amount of 90% by mass or more of the maximum absorption amount of the used absorbent article, ) to (4).
In this method, in the pretreatment step, the used absorbent article has a step of absorbing water in an amount of 90% by mass or more of the maximum absorption amount of the used absorbent article. That is, the used absorbent article can be fully swollen with water. As a result, a very high internal pressure can be created in the used absorbent article. Due to the internal pressure, the physical impact given to the used absorbent article during the decomposition process more reliably tears (peels off) the joint between the top sheet (nonwoven fabric or film) and the back sheet (film). ), allowing the absorbent material inside the used absorbent article to erupt (jump) out through the cracks.

(6) The separating step includes a step of removing the adhesive at the joint between the film and another member with a solvent that dissolves the adhesive at the joint, wherein (1) to ( The method according to any one of 5) may be used.
In this method, the adhesive at the joint between the film (example: back sheet film) and other members (example: top sheet film, non-woven fabric, absorbent material) is removed with a solvent, so the film and other members are removed. can be separated from each other while maintaining the shape as it is without breaking or the like. Therefore, constituent members such as films of absorbent articles can be efficiently recovered. Also, the film can be separated from other members without leaving adhesive on the film. As a result, the film can be reused as a high-purity resin, and adverse effects of the adhesive can be suppressed when the film is reused.

This method may be (7) the method according to (6) above, wherein the solvent contains at least one terpene selected from the group consisting of terpene hydrocarbons, terpene aldehydes and terpene ketones.
In this method, by using terpene as a solvent for dissolving the adhesive, the adhesive can be dissolved and removed more reliably. Furthermore, since terpene has a high oil stain cleaning effect, when used absorbent articles contain other oil components (eg, printing ink), the oil components can also be decomposed and removed. Thereby, the film can be made reusable as a highly pure resin.

(8) The separation step includes the step of removing the solvent by heating and drying the film after the step of removing the adhesive from the joint portion (6) or (7). The method described in .
Sterilization is extremely important in the reuse of used absorbent articles. In this method, the separated film is dried by heating, i.e., dried in a high-temperature atmosphere or hot air, so that the solvent remaining on the surface of the film is evaporated and removed, and the film is dried in a high-temperature atmosphere or hot air. can be sterilized with As a result, it is possible to obtain the effect of sterilization (disinfection) while removing the solvent, and to efficiently collect the constituent members such as the film of the absorbent article.

(9) the separating step comprises separating the pulp fibers from the separated mixture; and treating the separated pulp fibers with an aqueous solution containing an oxidizing agent to obtain the pulp fibers The method according to (2) above, which comprises the step of reducing the molecular weight of the remaining superabsorbent polymer, solubilizing it, and removing it.
In this method, the superabsorbent polymer remaining in the pulp fibers can be solubilized and removed by oxidation with an oxidizing agent (eg, ozone), so that high-purity pulp fibers with a low superabsorbent polymer content can be recovered. Therefore, it is possible to efficiently collect the constituent members of the absorbent article.

(10) The used absorbent article is at least one selected from the group consisting of disposable diapers, urine absorbing pads, sanitary napkins, bed sheets, and pet sheets (1) to (9) above. The method according to any one of the above may be used.
This method can be applied to at least disposable diapers, incontinence pads, sanitary napkins, bed sheets, and pet sheets as used absorbent articles.

According to the method of the present invention, when the constituent members of the used absorbent article are recycled, the constituent members such as the film can be efficiently recovered from the used absorbent article without breaking the used absorbent article. becomes possible.

Figure 2 is a flow chart illustrating one embodiment of the method of the present invention; FIG. 2 is a schematic diagram showing an example of the state change of the used absorbent article in the pretreatment step of FIG. 1; FIG. 2 is a schematic diagram showing an example of a decomposition method in the decomposition step of FIG. 1; FIG. 2 is a schematic diagram showing an example of a used absorbent article disassembled in the disassembling step of FIG. 1;

Hereinafter, a method for recovering constituent members from used absorbent articles according to embodiments of the present invention will be described. However, a used absorbent article is an absorbent article that has been used by a user, and is usually an absorbent article that has absorbed the liquid excretion of the user. However, in the present embodiment, used absorbent articles include used absorbent articles that have not absorbed excrement and unused articles.

A configuration example of an absorbent article will be described. The absorbent article comprises a topsheet, a backsheet, and an absorbent body disposed between the topsheet and the backsheet. Examples of absorbent articles include paper diapers, incontinence pads, sanitary napkins, bed sheets, and pet sheets. The topsheet, backsheet and absorbent body are formed from constituent members such as nonwoven fabrics, films, pulp fibers, superabsorbent polymers, etc., and are bonded together with an adhesive or the like. An example of the size of the absorbent article is about 15-100 cm in length and 5-100 cm in width.

Examples of constituent members of the surface sheet include nonwoven fabrics and films, and specific examples include liquid-permeable nonwoven fabrics, synthetic resin films having liquid-permeable pores, composite sheets thereof, and the like. Examples of constituent members of the backsheet include nonwoven fabrics and films, and specific examples include liquid-impermeable nonwoven fabrics, liquid-impermeable synthetic resin films, and composite sheets of these nonwoven fabrics and synthetic resin films. Here, the material for the nonwoven fabric or synthetic resin film is not particularly limited as long as it can be used as an absorbent article. and polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), among which polyethylene is preferred.

In the present embodiment, at least one of the topsheet and the backsheet of the absorbent article includes a film as a constituent member. An absorbent article to be used will be described as an example.

The backsheet may include a breathable exterior sheet on the side opposite to the absorbent body in the thickness direction. As the constituent members of the exterior sheet, the same constituent members as those of the back sheet can be used. The facing sheet is adhesively bonded to the backing sheet. Furthermore, the surface sheet may include water-repellent side sheets on both outer sides in the width direction. Examples of the constituent members of the side sheets include water-repellent nonwoven fabrics and breathable synthetic resin films. The sidesheets are adhesively bonded to the topsheet. In this embodiment, when the absorbent article includes an exterior sheet and side sheets, the film may include the exterior sheet and side sheets.

A filler (inorganic filler) may be contained in the film in order to impart liquid permeability and air permeability to the film, which is the constituent member described above, that is, to make the film porous. As a result, a large number of holes are formed in the film due to peeling that occurs at the interface between the resin of the film and the filler. The filler material is not particularly limited as long as it can be used as an absorbent article. Examples include calcium carbonate, barium sulfate, calcium sulfate, barium carbonate, zinc oxide, magnesium oxide, titanium oxide, talc, silica, clay, Kaolin, alumina, mica, or a combination of at least two of these. The moldability and stretchability of the film material, and the moisture permeability, air permeability, strength, etc. of the resulting porous film can be controlled by the filler content in the film material.

Absorbent components include absorbent material, ie, pulp fibers and superabsorbent polymers. The pulp fibers are not particularly limited as long as they can be used as absorbent articles, and examples thereof include cellulosic fibers. Examples of cellulosic fibers include wood pulp, crosslinked pulp, non-wood pulp, regenerated cellulose, semi-synthetic cellulose, and the like. The superabsorbent polymer (SAP) is not particularly limited as long as it can be used as an absorbent article. For example, polyacrylate, polysulfonate, and maleic anhydride water absorbent polymers mentioned.

One side and the other side of the absorbent body are respectively bonded to the topsheet and the backsheet via an adhesive. In a plan view, the portion (peripheral portion) of the topsheet that extends outside the absorber so as to surround the absorber is the portion of the backsheet that extends outside the absorber so as to surround the absorber. It is joined to the extended portion (peripheral portion) via an adhesive. Therefore, the absorbent body is wrapped inside 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 is softened by hot water, which will be described later, to lower the bonding strength. Examples include hot-melt adhesives. Hot-melt adhesives include, for example, rubber-based pressure-sensitive adhesives such as styrene-ethylene-butadiene-styrene, styrene-butadiene-styrene, and styrene-isoprene-styrene, or olefin-based pressure-sensitive or heat-sensitive adhesives such as polyethylene. agents and the like.

Next, a method for recovering the constituent members from the used absorbent article according to this embodiment will be specifically described. In this embodiment, used absorbent articles are collected, collected, or obtained from the outside for reuse (recycling). Further, in the present embodiment, each used absorbent article has the surface sheet on which excrement is excreted inside so that the excrement is not exposed on the front side and the odor is not diffused to the surroundings. and collected in a rolled or folded state. It should be noted that the used absorbent article does not have to be in a rolled state or the like.

FIG. 1 is a flow chart showing one embodiment of a method for recovering components from used absorbent articles. This method comprises a pretreatment step S1 of swelling a used absorbent article with water, and applying a physical impact to the swollen used absorbent article to divide the used absorbent article into at least a film and an absorbent material. and a separation step S3 for separating the decomposed film and the absorbent material. Each step will be described below.

In the pretreatment step S1, the used absorbent article is left in the state when it is collected from the outside, that is, without being destroyed or cut, and if it is rolled up or folded, it is left in that state ( (i.e., remains in its original shape) and absorbs water without deactivating the superabsorbent polymer of the absorbent body and swells. However, in the present embodiment, the used absorbent article is made to swell by absorbing warm water, or is made warm by heating the absorbed water after being made to absorb and swell with water. Hot water refers to water at a temperature higher than normal temperature (20° C.±15° C. (5 to 35° C.): JIS Z 8703).

Normally, the amount of liquid excrement actually absorbed by a used absorbent article is very small compared to the maximum absorption amount that the absorbent article can absorb (example: about 10 to 20% of the maximum absorption amount). mass%). In the present embodiment, in the pretreatment step S1, the used absorbent article is immersed in warm water so that the amount of water is close to the maximum absorption amount of the used absorbent article (example: 80% by mass or more of the maximum absorption amount). absorb. Alternatively, the used absorbent article is soaked in room temperature water to absorb water to an amount close to the maximum absorption amount of the used absorbent article, and then the whole used absorbent article is heated to the temperature of warm water. Thereby, the used absorbent article can be brought into a highly swollen state with warm water or normal temperature water (hereinafter also simply referred to as "warm water"). As a result, a very high internal pressure is created in the used absorbent article. The purpose of making the water warm is mainly to weaken the adhesive force of the adhesive, as will be described later.

FIG. 2 is a schematic diagram showing an example of the state change of the used absorbent article in the pretreatment step S1 of FIG. However, FIG. 2(a) shows the state of the used absorbent article before immersion in warm water, and FIG. 2(b) shows the state of the used absorbent article after immersion in warm water. As shown in FIG. 2(a), the used absorbent article 1 is initially in a rolled or folded state with the backsheet 3 facing outward (with the topsheet 2 hidden inside). When the used absorbent article 1 in that state is immersed in warm water, the absorbent core 4 of the used absorbent article 1 absorbs the warm water and expands in the warm water. As a result, the internal pressure of the used absorbent article 1 increases. The internal pressure exerts a force to open the used absorbent article 1 outward. As a result, as shown in FIG. 2(b), the used absorbent article 1 in a rolled or folded state is opened outward to a generally flat state so as to expose the topsheet 2. become. That is, the used absorbent article 1 can be laid flat in warm water. At this time, since the used absorbent article 1 absorbs a large amount of warm water and is greatly expanded, the surface of the used absorbent article 1, that is, either the top sheet 2 or the back sheet 3 enveloping the absorbent body 4, is exposed. Some parts are likely to break easily. That is, the pretreatment step S1 can bring the used absorbent article to a state where one of its surfaces is likely to tear and tear. When the used absorbent article 1 is in a flat state from the beginning, any portion of the surface of the absorbent article 1 is likely to burst easily in that state. This state cannot occur when the used absorbent article of Patent Document 1 is broken or the like.

Further, when the used absorbent article is immersed in warm water and/or absorbs the warm water, the adhesive (example: hot-melt adhesive) used for bonding between the constituent members is softened by the heat of the warm water. and the bonding strength of the adhesive can be reduced. For example, the adhesive that joins the peripheral edge portion of the top sheet and the peripheral edge portion of the back sheet can be softened by the heat of warm water, and the bonding strength of the adhesive can be reduced. Furthermore, the adhesive that joins the top sheet and the absorbent body and the adhesive that joins the back sheet and the absorbent body are softened by the heat of the warm water, and the bonding strength of these adhesives can be reduced.

As described above, in the pretreatment step S1, due to the expansion of the absorbent body of the used absorbent article, some part of the surface of the used absorbent article was likely to burst, and the bonding strength of the adhesive was reduced. state can be produced. By putting the used absorbent article into such a state, it is possible to reliably disassemble the used absorbent article in the disassembly step described later.

The temperature of the hot water in the pretreatment step S1 is not particularly limited as long as the adhesive of the used absorbent article can be softened. In other words, the pretreatment step S1 preferably includes a step of swelling the used absorbent article with warm water of 70°C or higher and 98°C or lower. An adhesive that joins the film (the back sheet in this embodiment) and other members (the nonwoven fabric of the top sheet and the absorbent material of the absorbent body in this embodiment) by setting the temperature of the hot water to 70° C. or higher. can be softened by the heat of warm water, and the bonding strength of the adhesive can be further reduced. Further, by setting the temperature of the warm water to 98° C. or less, the warm water is surely present as a liquid, so that the used absorbent article can more reliably absorb the warm water. The expansion of the absorbent body and the heat of the warm water can more reliably create a state where the surface of the used absorbent article is about to burst and the bonding strength of the adhesive is reduced. The temperature of the warm water is more preferably 75°C or higher and 90°C or lower, and still more preferably 75°C or higher and 85°C or lower. For temperature measurement, measure the temperature of warm water in which the used absorbent article is soaked, or measure the temperature 5 mm inside from the surface of the used absorbent article that has absorbed water to an amount close to the maximum absorption amount ( (insert the tip of the temperature sensor).

In addition, sterilization of constituent materials is extremely important in the reuse of used absorbent articles. By setting the temperature of the warm water to 70° C. or higher, it is possible to achieve the effect of sterilizing (disinfecting) the used absorbent article, which is preferable.

The treatment time in the pretreatment step S1, that is, the time during which the used absorbent article is immersed in warm water is not particularly limited as long as the absorbent core of the used absorbent article can swell, and is, for example, 2 to 60 minutes, preferably 4 to 30 minutes. If the time is too short, the absorbent body cannot expand sufficiently, and if it is too long, time is wasted and the processing cost is increased unnecessarily.

In addition, the amount of hot water absorbed by the absorbent in the pretreatment step S1 is not particularly limited as long as the absorbent can expand to such an extent that the used absorbent article can be decomposed in the decomposition step described later. 80% by mass or more, preferably 90% by mass or more, of the maximum absorption amount. In other words, the pretreatment step S1 preferably includes a step of allowing the used absorbent article to absorb hot water (water) in an amount of 90% by mass or more of the maximum absorption amount of the used absorbent article. Thereby, the used absorbent article can be fully swollen with water. As a result, an extremely high internal pressure can be generated in the absorbent body of the used absorbent article. Due to the extremely high internal pressure, if the used absorbent article is in a folded state or the like, the used absorbent article can be extremely easily unfolded into a flat state. At the same time, the expansion of the absorbent body can more reliably create a state where the surface of the used absorbent article is about to burst. As a result, the used absorbent article can be more reliably decomposed by the physical impact given to the used absorbent article in the later-described decomposition step.

Here, the maximum absorption amount is measured by the following procedure.
(1) An unused absorbent article is dried in an atmosphere of 100° C. or higher, and the mass of the absorbent article is measured.
(2) If a stretchable material that can form a pocket that makes it difficult for water to reach the absorbent body (example: stretchable material around the legs or around the waist) is arranged in the absorbent article, cut into the stretchable member. to flatten the absorbent article.
(3) Immerse the absorbent article face down in a water bath filled with enough tap water and leave for 30 minutes.
(4) After standing, the absorbent article is placed on a net with the surface sheet facing down, drained for 20 minutes, and then the weight of the absorbent article is measured.
Then, the difference in mass before and after immersion in tap water is defined as the maximum absorption amount.

Furthermore, all used absorbent articles are made to absorb warm water up to roughly the maximum absorption amount of the used absorbent article, so that the weight per used absorbent article is roughly the same for all used absorbent articles. (if the type of used absorbent article is the same). Therefore, by dividing the weight of all used absorbent articles at that time by the weight of each used absorbent article at that time, the collected used absorbents that were unknown at the time of collection of the disposable absorbent article The total number of sexual items can be approximated. Thereby, the recovery amount of each component can be roughly estimated. For example, the total number of used absorbent articles collected can be used to estimate the number of films to be collected and the amount of adhesive to be processed. Therefore, in the steps after the pretreatment step S1, it is possible to easily estimate and easily adjust the amount of the treatment liquid when each constituent member is individually treated.

Next, in the decomposition step S2, physical impact is applied to the used absorbent article expanded and swollen by the pretreatment step S1, and the used absorbent article is divided into at least a film (back sheet) and an absorbent material (absorbent material). ) and In this embodiment, it is decomposed into a film (back sheet), a non-woven fabric (top sheet), and an absorbent material (absorbent body).

The used absorbent article is flattened by the pretreatment step S1, and is about to burst at some point on the surface due to expansion. is in a state of reduced bonding strength. Therefore, in the disassembly step S2, by applying a physical impact to the used absorbent article in that state, the surface sheet (nonwoven fabric) and the back sheet (nonwoven fabric) and the back sheet (nonwoven fabric) and the back sheet (which have particularly reduced bonding strength) can be removed from any part of the surface. film) is torn off. Thereby, the joint portion can be torn (peeled off). The physical impact is not particularly limited, but for example, a method of hitting the used absorbent article against a surface made of a harder material than the used absorbent article, or a method of placing the used absorbent articles facing each other. Alternatively, a method of pressing from both sides while sandwiching between a pair of rolls and passing through the rolls may be mentioned. Even if the water in which the used absorbent article is immersed in the pretreatment step S11 is at room temperature, the used absorbent article can be expanded and the surface is likely to burst. It is possible for a used absorbent article to burst (tear) at any point on the surface, even if the atmosphere in which the article is impacted is at room temperature.

In this embodiment, the following method, which is an example of a method of hitting a used absorbent article against a surface made of a material harder than the used absorbent article, is adopted. FIG. 3 is a schematic diagram showing an example of the decomposition method in the decomposition step S2 of FIG. 3(a) to 3(c) show a method of applying a physical impact to the used absorbent article 1. FIG. That is, the decomposition step S2 includes a loading step of loading the swollen used absorbent article 1 into the rotating drum 20, and an impacting step of rotating the rotating drum 20 to give a physical impact to the used absorbent article 1. and

As shown in FIG. 3A, the rotary drum 20 is a horizontal rotary drum that rotates (R) around a virtual rotary axis A extending in the horizontal direction HD. As the rotating drum 20, for example, a rotating drum of a washing tub of a horizontal washing machine can be used. Therefore, the disassembling step S2 can be performed using a horizontal washing machine. As the horizontal washing machine, for example, ECO-22B manufactured by Inamoto Seisakusho Co., Ltd. can be used. The rotating drum 20 has a lower lower area LA, an upper upper area UA, and a central area MA between the lower area LA and the upper area UA in the vertical direction VD. When the inner diameter of the rotating drum 20 is D, the lower area LA is preferably an area of D/3 below the vertical direction VD in the rotating drum 20, more preferably an area of D/4. The upper area UA is preferably an area of D/3 above the rotary drum 20 in the vertical direction VD, more preferably an area of D/4. The inner diameter D×depth is, for example, 50 to 150 cm×30 to 120 cm.

In the loading step, as shown in FIG. 3(a), the used absorbent article 1 is placed on the inner surface of the rotating drum 20 in the lower area LA. At this time, the number of used absorbent articles 1 to be placed is an amount that allows sufficient impact to be applied to the used absorbent articles 1 in the impact step, and the maximum is within the lower area LA. is a number. If the number is too large, the movement of the used absorbent article within the rotating drum 20 will be too small to impact the used absorbent article.

In the subsequent impact step, as shown in FIG. 3(b), the rotating drum 20 is rotated to lift the used absorbent article 1 from the lower area LA within the rotating drum 20 to the upper area UA. Then, as shown in FIG. 3(c), the used absorbent article 1 is lowered by gravity from the upper area UA to the lower area LA and collided with the inner surface of the rotary drum 20 in the lower area LA. Through such steps, physical impact can be applied to the used absorbent article 1 .

The rotation speed of the rotating drum 20 is not particularly limited as long as the impact process can be realized, and is, for example, 30 times/minute to 100 times/minute. In addition, the warm water absorbed in the used absorbent article 1 keeps the temperature of the used absorbent article 1 at a relatively high temperature. Therefore, the temperature of the atmosphere in the rotating drum 20 is preferably 70° C. or higher, more preferably 75° C. or higher. From the viewpoint of handling the used absorbent article 1, the temperature inside the rotating drum 20 is preferably 98°C or lower, more preferably 90°C or lower. It is preferable that the amount of water in the rotating drum 20 is as small as possible, at least to the extent that the used absorbent article 1 does not fall below the surface of the water during the impact process. When the used absorbent article 1 is below the surface of the water, the impact on the used absorbent article 1 is absorbed by the water, making it difficult to apply the desired impact to the used absorbent article 1 .

The treatment time in the impact step, that is, the time during which the rotating drum 20 is rotated is not particularly limited as long as the top sheet 2 and the back sheet 3 can be decomposed from the absorbent material, but is, for example, 2 to 40 minutes. , preferably 4 to 20 minutes.

FIG. 4 is a schematic diagram showing an example of the used absorbent article 1 disassembled in the disassembling process of FIG. The used absorbent article 1 is torn due to physical impact, breaking the joint between the topsheet 2 (nonwoven fabric) and the backsheet 3 (film). At the same time, the absorbent material (pulp fibers 8 and water-absorbent polymer 6) in the used absorbent article 1 is ejected (jumped out) through the cracks 10 due to the internal pressure of the absorbent body 4. . Thereby, the used absorbent article 1 can be decomposed into the top sheet 2 (nonwoven fabric), the back sheet 3 (film), and the absorbent material (pulp fibers 8 and water absorbent polymer 6).

In the present embodiment, particularly, the horizontal rotating drum 20 is used to strike the used absorbent article 1 from the upper area UA toward the lower area LA by gravity, thereby impacting the used absorbent article 1. can give By continuing the rotation of the rotating drum 20, such an impact can be applied stably, continuously and easily. As a result, the joint portion between the top sheet 2 (nonwoven fabric) and the back sheet 3 (film) in the used absorbent article 1 can be more stably torn (peeled off), and the used absorbent article 1 can be absorbed by the film. It can be reliably decomposed by the body material. Also, existing washing machines can be used.

A separation step S3 then separates the decomposed film (backsheet) and absorbent material (pulp fibers and water-absorbing polymer). In this embodiment, a plurality of films (backsheet) and a plurality of nonwoven fabrics (topsheet) are separated from the absorbent material (pulp fibers and water-absorbing polymer). However, the nonwoven fabric may be bonded to the film. At this time, the topsheet (nonwoven fabric) and the backsheet (film) generally maintain the same shape as the absorbent article, that is, the original shape. Therefore, the size, shape, and mass of the topsheet (nonwoven fabric) and backsheet (film) are clearly different from those of the absorbent material, compared to the case of being broken into pieces before decomposition. Therefore, in the separation step S3, the topsheet (nonwoven fabric) and backsheet (film) can be easily separated from the absorbent material (pulp fibers and water-absorbing polymer). Examples of the separation method include a method using a sieve through which the absorbent material is passed but not the topsheet and the backsheet. Thereby, the constituent member such as the film can be separated from the other constituent members while maintaining the shape as it is without breaking or the like. Therefore, constituent members such as films of absorbent articles can be efficiently recovered.

In the present embodiment, the separation step S3 includes an inactivation step S31 of inactivating the superabsorbent polymer with an aqueous solution containing an inactivating agent, a film and a pulp fiber before separating the film and the absorbent material. , and a mixture containing the inactivated superabsorbent polymer and the sewage discharged from the superabsorbent polymer due to the inactivation, a first separation step S32.

In the inactivation step S31, before the first separation step S32, the topsheet (nonwoven fabric), the backsheet (film) and the absorbent material (pulp fiber and superabsorbent polymer) are combined, and the superabsorbent polymer can be inactivated. immerse in an aqueous solution containing a suitable inactivating agent. As a result, the superabsorbent polymer adhering to the topsheet, backsheet and pulp fibers can be inactivated. As a result, the highly viscous superabsorbent polymer prior to deactivation can be converted to a less viscous superabsorbent polymer by dehydration due to deactivation.

Here, the inactivating agent is not particularly limited, but examples thereof include inorganic acids, organic acids, lime, calcium chloride, magnesium sulfate, magnesium chloride, aluminum sulfate, and aluminum chloride. Among them, inorganic acids and organic acids are preferable because they do not leave ash on the pulp fibers. When an inorganic acid or organic acid is used as the inactivating agent, the pH of the inorganic acid aqueous solution or organic acid aqueous solution is 2.5 or less, preferably 1.3 to 2.4. Therefore, an aqueous solution containing an inactivating agent can be called an acidic aqueous solution. If the pH is too high, the water absorption capacity of the superabsorbent polymer cannot be sufficiently lowered. Moreover, there is also a possibility that the sterilization ability may be lowered. If the pH is too low, the equipment may be corroded, and a large amount of alkaline chemicals will be required for neutralization during wastewater treatment. Examples of inorganic acids include sulfuric acid, hydrochloric acid, and nitric acid. Sulfuric acid is preferred from the viewpoints of chlorine-free and cost. On the other hand, the organic acid includes citric acid, tartaric acid, glycolic acid, malic acid, succinic acid, acetic acid, ascorbic acid and the like, with citric acid being particularly preferred. Due to the chelating effect of citric acid, metal ions and the like in the excrement can be trapped and removed, and the cleaning effect of citric acid is expected to be highly effective in removing dirt components. 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 inorganic acid concentration of the inorganic acid aqueous solution is not limited as long as the pH of the inorganic acid aqueous solution is 2.5 or less, but when the inorganic acid is sulfuric acid, the concentration of sulfuric acid is preferably 0.1 mass % or more and 0.5 % by mass or less. The organic acid concentration of the organic acid aqueous solution is not limited as long as the pH of the organic acid aqueous solution is 2.5 or less, but when the organic acid is citric acid, the concentration of citric acid is preferably 2% by mass or more and 4% by mass. It is below.

The processing temperature of the inactivation step S31, that is, the temperature of the aqueous solution containing the inactivating agent is not particularly limited as long as the inactivating reaction proceeds. The treatment temperature may be room temperature or may be higher than room temperature, such as 15 to 30°C. In addition, the processing time of the deactivation step S31, that is, the time of soaking the top sheet, the back sheet and the absorbent material in the aqueous solution containing the deactivator is not particularly limited as long as the superabsorbent polymer is deactivated and dehydrated. , for example, 2 to 60 minutes, preferably 5 to 30 minutes. Moreover, the amount of the aqueous solution in the inactivation step S31, that is, the amount of the aqueous solution containing the inactivating agent is not particularly limited as long as the inactivation reaction proceeds. The amount of the aqueous solution is preferably 300 to 3000 parts by weight, more preferably 500 to 2500 parts by weight, still more preferably 1000 to 2000 parts by weight, based on 100 parts by weight of the used absorbent article.

In the first separation step S32, a mixture containing a top sheet (nonwoven fabric) and a back sheet (film), pulp fibers, inactivated superabsorbent polymers, and sewage discharged from the inactivated superabsorbent polymers , separates However, the sewage is water released from the superabsorbent polymer by dehydration with an aqueous solution containing an inactivating agent in the inactivation step S31, that is, sewage containing excrement-derived liquid and hot water-derived water.

In the first separation step S32, the method of separating the topsheet and backsheet from the pulp fibers, the superabsorbent polymer and the sewage is not particularly limited. For example, the products (surface sheet, back sheet, pulp fiber, superabsorbent polymer, sewage, etc.) produced by the inactivation step are discharged through a screen with an opening of 5 to 100 mm, preferably 10 to 60 mm. . The products can thereby be separated by leaving the pulp fibers, the superabsorbent polymer and the sewage in the drain and the top and back sheets on the screen. It should be noted that other large objects such as non-woven fabrics and films may remain on the screen. In particular, since the superabsorbent polymer is in a highly viscous state before deactivation, it is not easy to separate the superabsorbent polymer adhering to the topsheet, backsheet and pulp fibers. However, after deactivation, the superabsorbent polymer becomes less viscous due to dehydration. Can be easily separated. Therefore, it is possible to efficiently separate and collect the constituent members of the absorbent article.

In this embodiment, the separation step S3 may further include a second separation step S33 of removing the adhesive at the joint between the film and another member using a solvent that dissolves the adhesive at the joint. In this embodiment, the adhesive is removed from the joints of the film, the nonwoven fabric, and the absorbent material using a solvent that dissolves the adhesive at the joints.

In the second separation step S33, the adhesive at the joint between the film (back sheet) and other members (non-woven fabric of the top sheet, absorbent material remaining on the surface of the top sheet or the back sheet, etc.) is removed with a solvent. Remove by As a result, the film and other members can be separated from each other while maintaining their shapes without breaking or the like. Therefore, constituent members such as films of absorbent articles can be efficiently collected. In addition, since the film can be separated from other members without leaving an adhesive on the film, the film can be reused as a highly pure resin. As a result, it is possible to suppress the adverse effect of the adhesive when the film is reused. The nonwoven fabric is the same as the film.

The solvent used in the second separation step S33 is not particularly limited as long as it can dissolve the adhesive. mentioned. In this step, an aqueous solution containing Tempel is used, and the concentration of Tempel in the aqueous solution is, for example, 0.05% by mass or more and 2% by mass or less. It is preferably 0.075 to 1% by mass. If the terpene concentration is too low, it may not be possible to dissolve the adhesive at the joint. If the terpene concentration is too high, the cost can be high. Tempel not only dissolves adhesives such as hot-melt adhesives, but also has a greasy cleansing effect. Therefore, if there is printing on a constituent member of the absorbent article such as the backsheet, Tempel can decompose and remove the printing ink as well.

Terpene hydrocarbons include, for example, myrcene, limonene, pinene, camphor, sapinene, phellandrene, paracymene, ocimene, terpinene, carene, zingiberene, caryophyllene, bisabolene, and cedrene. Among them, limonene, pinene, terpinene, and carene are preferred. Terpene aldehydes include, for example, citronellal, citral, cyclocitral, safranal, ferrandral, perillaldehyde, geranial and neral. Terpene ketones include, for example, camphor and tsuyoshi. Among terpenes, terpene hydrocarbons are preferred, and limonene is particularly preferred. There are three types of limonene: d-limonene, l-limonene and dipentene (dl-limonene), any of which can be preferably used. A terpene can also be used individually by 1 type, and can also be used in combination of 2 or more type.

The processing temperature of the second separation step S33, that is, the temperature of the solvent-containing aqueous solution, is not particularly limited as long as the adhesive is dissolved and the used absorbent article is decomposed into constituent members. The treatment temperature may be room temperature or may be higher than room temperature, such as 15 to 30°C. Further, during the processing time of the second separation step S33, that is, the time during which the top sheet, the back sheet and the absorbent material are immersed in the aqueous solution containing the solvent, the dissolution of the adhesive progresses and the used absorbent article is decomposed into constituent members. As long as it is not particularly limited. The treatment time is, for example, 2 to 60 minutes, preferably 5 to 30 minutes. The amount of the aqueous solution in the second separation step S33, ie, the amount of the solvent-containing aqueous solution, is not particularly limited as long as the adhesive is dissolved and the used absorbent article is decomposed into constituent members. The amount of the aqueous solution is preferably 300 to 3000 parts by weight, more preferably 500 to 2500 parts by weight, based on 100 parts by weight of the used absorbent article. By the second separation step S33, the amount of the adhesive remaining on the film, nonwoven fabric, or absorbent material can be reduced to 1% by mass or less with respect to the film, nonwoven fabric, or absorbent material.

In addition, in the present embodiment, as another preferred mode, the second separation step S33 may be performed together with the inactivation step S31. That is, the adhesive adhering to the topsheet, backsheet and pulp fibers may be dissolved while inactivating the superabsorbent polymer adhering to the topsheet, backsheet and pulp fibers. In this case, an aqueous solution containing both an inactivating agent and a solvent is used as the aqueous solution in which the topsheet, backsheet, pulp fibers and superabsorbent polymer are immersed. As a result, in the deactivation step S31, the back sheet (film), the top sheet (nonwoven fabric), and the absorbent (pulp fibers and superabsorbent polymer) can be substantially separated in the aqueous solution. Then, in the subsequent first separation step S32, the back sheet (film) and top sheet (nonwoven fabric) can be separated from the absorber (pulp fiber and superabsorbent polymer), and the second separation step S33 is omitted. can. In this case, the backsheet (film) and topsheet (nonwoven fabric) are substantially separated by removing the adhesive.

In the present embodiment, the separation step S3 is performed after the step of removing the adhesive at the joint portion, followed by drying the film by heating, i.e., drying in an atmosphere at a temperature higher than room temperature or in hot air to remove the solvent. A step S34 may be further included. In this embodiment, the nonwoven fabric is also dried in this step.

Sterilization is extremely important in the reuse of used absorbent articles. In the first drying step S34, the separated film (back sheet) and non-woven fabric (top sheet) are dried in a high-temperature atmosphere or hot air. The drying temperature is, for example, 105 to 210°C, preferably 110 to 190°C. The drying time is, for example, 10 to 120 minutes, preferably 15 to 100 minutes, depending on the drying temperature. As a result, not only can the solvent remaining on the surface of the film and nonwoven fabric be evaporated and removed, but also the film and nonwoven fabric can be sterilized with a high-temperature atmosphere or hot air. As a result, it is possible to achieve a sterilization (disinfection) effect while removing the solvent. Therefore, films and nonwoven fabrics, which are components of absorbent articles, can be efficiently collected. Since the film and the nonwoven fabric clearly differ in density and properties, they can be easily separated. The recovered film and non-woven fabric can be recycled, for example, into pellets respectively, which can then be further recycled into plastic bags and films. At this time, the amount of adhesive remaining in the recovered film and nonwoven fabric is 1% by mass or less relative to the film or nonwoven fabric, so the amount of adhesive remaining in the pellets, plastic bags, or film is also relative to the pellets, plastic bags, or film. can be reduced to 1% by mass or less.

On the other hand, in the present embodiment, the separation step S3 includes a third separation step S35 of separating the pulp fibers from the separated mixture, and a treatment of the separated pulp fibers with an aqueous solution containing an oxidant to convert the pulp fibers into pulp fibers. An oxidizing agent treatment step S36 of reducing the molecular weight of the remaining superabsorbent polymer, solubilizing it, and removing it may also be included.

In the third separation step S35, the method for separating pulp fibers from the separated mixture (including pulp fibers, superabsorbent polymer, and sewage) is not particularly limited, but for example, the separated mixture is separated with an opening of 0.5 mm. It is discharged through a screen with an opening of 1 to 4 mm, preferably 0.15 to 2 mm. As a result, the superabsorbent polymer and sewage remain in the drainage, and the pulp fibers (with the superabsorbent polymer remaining on the surface) remain on the screen, so that the pulp fibers can be separated from the mixture. Although this pulp fiber contains many impurities, it can be used depending on the application.

Furthermore, in the oxidizing agent treatment step S36, the inactivated superabsorbent polymer remaining on the surface of the separated pulp fibers is oxidatively decomposed by an oxidizing agent, reduced in molecular weight, solubilized, and removed from the surface of the pulp fibers. Remove. Here, the state in which the superabsorbent polymer is oxidatively decomposed, reduced in molecular weight, and solubilized refers to the state in which it passes through a 2 mm screen. As a result, impurities such as the superabsorbent polymer contained in the pulp fibers can be removed, and pulp fibers with high purity can be produced. In addition, secondary sterilization, bleaching, and deodorization of pulp fibers can be performed by the oxidizing agent treatment.

The oxidizing agent is not particularly limited as long as it can oxidatively decompose the inactivated superabsorbent polymer, reduce its molecular weight, and solubilize it. Examples thereof include chlorine dioxide, ozone, and sodium hypochlorite. Among them, ozone is preferable from the viewpoint of high decomposition performance and bleaching performance. When ozone is used as the oxidizing agent, oxidizing agent treatment is carried out by contacting a mixture containing pulp fibers and superabsorbent polymers with ozone, specifically by blowing ozone into wastewater containing pulp fibers and superabsorbent polymers. It can be performed. Ozone can be generated using, for example, an ozone water generator (e.g., ozone water exposure tester ED-OWX-2 manufactured by Ecodesign Co., Ltd., ozone generator OS-25V manufactured by Mitsubishi Electric Corporation).

When ozone is blown into wastewater containing pulp fibers and superabsorbent polymers, the ozone concentration in the wastewater is not particularly limited as long as it is a concentration that can decompose the superabsorbent polymer. For example, 1 to 50 mass ppm. and preferably 2 to 40 mass ppm. If the concentration is too low, the superabsorbent polymer cannot be completely solubilized and may remain in the pulp fibers. Conversely, if the concentration is too high, the oxidizing power also increases, which may damage pulp fibers and pose a safety problem. The ozone treatment temperature is not particularly limited as long as it can decompose the superabsorbent polymer. The ozone treatment time is not particularly limited as long as it can decompose the superabsorbent polymer, but is, for example, 10 to 120 minutes, preferably 20 to 100 minutes. If the ozone concentration is high, a short time is sufficient, and if the ozone concentration is low, a long time is required. When ozone is blown into wastewater containing pulp fibers and deactivated superabsorbent polymers, the wastewater is preferably acidic. More preferably, the pH of the effluent is 2.5 or less, more preferably 1.5-2.4. By treating in an acidic state, the effect of decomposing and removing the superabsorbent polymer by ozone is improved, and the superabsorbent polymer can be decomposed in a short period of time.

In the present embodiment, the separation step S3 includes a fourth separation step S37 of separating the pulp fibers treated with the aqueous solution containing the oxidant from the aqueous solution containing the oxidant, and a fourth separation step S37 of drying the separated pulp fibers. 2 drying step S38.

In the fourth separation step S37, the method of separating the pulp fibers from the aqueous solution containing the oxidizing agent is not particularly limited, but for example, the treatment liquid containing the pulp fibers is passed through a screen having an opening of 0.15 to 2 mm. There is a method to make When the treated liquid containing pulp fibers is passed through a screen with an opening of 0.15 to 2 mm, the waste water containing the products of oxidative decomposition of the superabsorbent polymer passes through the screen, leaving the pulp fibers on the screen.

Subsequently, in a second drying step S38, the separated pulp fibers treated with an aqueous solution containing an oxidizing agent are dried in a high-temperature atmosphere or hot air. The drying temperature is, for example, 105 to 210°C, preferably 110 to 190°C. The drying time is, for example, 10 to 120 minutes, preferably 15 to 100 minutes, depending on the drying temperature. As a result, the solvent remaining on the surface of the pulp fibers is evaporated and removed, and high-purity pulp fibers with an extremely low superabsorbent polymer content can be recovered. Therefore, the constituent members of the absorbent article can be collected efficiently. In addition, pulp fibers can be sterilized (disinfected) with a high-temperature atmosphere or hot air.

In the present embodiment, in the pretreatment step S1, the used absorbent article is kept in the same shape without breaking, etc., and is made into a state of being greatly swollen with water without inactivating the superabsorbent polymer. be able to. This can create a very high internal pressure within the used absorbent article to the point where it is likely to burst at some point on its surface. Then, in the decomposition step S2, by applying a physical impact to the used absorbent article in such a state, any part of its surface is torn, and the internal absorbent material is ejected to the outside. can be made Thereby, the used absorbent article can be decomposed into at least the film (backsheet) and the absorbent material. At this time, since the film generally maintains its original shape, it can be easily separated from the absorbent material in the subsequent separation step S3. Thereby, the constituent member such as the film can be separated from the other constituent members while maintaining the shape as it is without breaking or the like. Therefore, it is possible to efficiently collect the constituent members of the absorbent article.

In this embodiment, as a preferred form, the hot-melt adhesive for bonding the constituent members of the absorbent article can be dissolved at room temperature by using terpene for removing the adhesive. As a result, the absorbent article can be easily and neatly disassembled, the pulp fibers and the superabsorbent polymer can be separated from the absorbent article, and the nonwoven fabric and the film can be separated while leaving the individual member forms. That is, the pulp fibers, the film, and the nonwoven fabric can be easily and separately collected without crushing the absorbent article or going through a complicated separation process. When limonene is used as a terpene, it has a refreshing citrus odor as a secondary effect of limonene, so that the odor derived from excrement is masked to some extent, and the burden of odor on workers and the impact of odor on neighbors can be reduced. Since limonene is a monoterpene and structurally similar to styrene, it can dissolve styrenic hot-melt adhesives commonly used in absorbent articles. Since the absorbent article can be washed at room temperature, energy costs can be reduced and odor generation and diffusion can be suppressed. Terpenes are highly effective in removing oil stains, and in addition to dissolving hot-melt adhesives, if there is printing on the film, the printing ink can also be decomposed and removed, and the printed film can also be recovered as a high-purity plastic material. is.

Further, when an organic acid aqueous solution having a pH of 2.5 or less is used to inactivate the superabsorbent polymer, the pulp fibers are less likely to deteriorate. In addition, when citric acid is used as the organic acid, the chelating effect and detergency of citric acid can be expected to have the effect of removing excrement-derived dirt components. In addition, a sterilizing effect and a deodorizing effect against alkaline odors can be expected.

Furthermore, by decomposing and removing the superabsorbent polymer with an oxidizing agent, it is possible to prevent contamination of pulp fibers and a rapid increase in sewage due to water absorption by the superabsorbent polymer. By adjusting the type and concentration of the oxidizing agent to be used, it is possible to simultaneously perform oxidative decomposition and sterilization of the superabsorbent polymer. In addition, when the oxidizing agent treatment process is not provided or when ozone is used as the oxidizing agent in the oxidizing agent treatment process, chlorine-based chemicals are not used at all. RPF manufacturing is possible. If the film is sorted and collected, it can be recycled as a raw material for bags and films. Since no salts are used during the treatment process, no residual salt remains on the pulp fibers, making it possible to recover high-quality pulp with low ash content.

The superabsorbent polymer can be recovered from the wastewater containing the superabsorbent polymer and sewage separated in the third separation step S35. The recovery method is not particularly limited, but examples thereof include a method using a sieve, and a method of recovering the water absorbing ability of the recovered water-absorbent polymer includes, for example, a method of treatment with an aqueous alkali metal salt solution. Further, the remaining waste water (with ozone dissolved at about 10 ppm) separated in the fourth separation step S37 may be circulated to the pretreatment step S1. As a result, the pretreatment in the pretreatment step S1 and the sterilization with ozone can be performed simultaneously without wasting waste water containing ozone.

The method according to the present embodiment can be suitably used for individually recovering constituent members such as films and absorbent members from used absorbent articles.

The above embodiment describes the case where the constituent member of the back sheet is a film and the constituent member of the top sheet is non-woven fabric. However, the embodiment in which the constituent member of the back sheet is a nonwoven fabric and the constituent member of the top sheet is a film, or the constituent member of both the back sheet and the top sheet is a film, is the same as the above embodiment. It can be realized by the same method as , and the same effect can be obtained.

The absorbent article of the present invention is not limited to the above-described embodiments, and can be appropriately combined and modified without departing from the scope and spirit of the present invention.

REFERENCE SIGNS LIST 1 Used absorbent article 2 Topsheet 3 Backsheet 4 Absorber S1 Pretreatment step S2 Decomposition step S3 Separation step

Claims (10)

a topsheet, a backsheet, and an absorbent body disposed between the topsheet and the backsheet, wherein at least one of the topsheet and the backsheet includes a film as a constituent member, and the absorbent body is a method of recovering a component from an absorbent article containing an absorbent material as a component,
a pretreatment step of swelling the absorbent article with water;
In a horizontal rotating drum, the surface of the water in the rotating drum is below the swollen absorbent article. a disassembling step of dropping the absorbent article into at least the film and the absorbent material while maintaining the original shape of the absorbent article by applying a physical impact to the absorbent article;
a separation step of separating the decomposed film and the absorbent material while maintaining the original shape of the film;
comprising
Method. The absorbent material comprises a superabsorbent polymer and pulp fibers,
The separation step includes
deactivating the superabsorbent polymer with an aqueous solution containing a deactivating agent prior to separating the film and the absorbent material;
separating the film from a mixture comprising the pulp fibers, the deactivated superabsorbent polymer and sewage discharged from the superabsorbent polymer due to deactivation;
including,
The method of claim 1. The decomposition step includes
putting the swollen absorbent article into the rotating drum;
The rotating drum, which is not filled with water , is rotated to lift the absorbent article from the lower lower region vertically in the rotating drum to the upper upper region, and the absorbent article is lifted from the upper region by gravity. giving a physical impact to the absorbent article by dropping it into the lower area and colliding with the inner surface of the rotating drum in the lower area;
including,
3. A method according to claim 1 or 2. The pretreatment step includes a step of swelling the absorbent article with the water at 70° C. or higher and 98° C. or lower.
4. A method according to any one of claims 1-3. The pretreatment step includes a step of causing the absorbent article to absorb the water in an amount of 90% by mass or more of the maximum absorption amount of the absorbent article.
5. A method according to any one of claims 1-4. The separating step includes a step of removing the adhesive at the joint portion with a solvent that dissolves the adhesive at the joint portion between the film and another member.
6. A method according to any one of claims 1-5. The solvent contains at least one terpene selected from the group consisting of terpene hydrocarbons, terpene aldehydes and terpene ketones,
7. The method of claim 6. The separation step includes a step of removing the solvent by heating and drying the film after the step of removing the adhesive from the joint portion.
8. A method according to claim 6 or 7. The separating step includes separating the pulp fibers from the separated mixture;
a step of treating the separated pulp fibers with an aqueous solution containing an oxidizing agent to reduce the molecular weight of the superabsorbent polymer remaining in the pulp fibers, solubilizing and removing the polymer;
including,
3. The method of claim 2. The absorbent article is at least one selected from the group consisting of disposable diapers, urine absorbing pads, sanitary napkins, bed sheets, and pet sheets.
10. A method according to any one of claims 1-9.

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