JP2019058906A - Method for collecting component member from used absorptive article - Google Patents

Abstract

To provide a method for efficiently collecting a component member from a used absorptive article without breaking the used absorptive article when the component member of the used absorptive article is recycled.SOLUTION: A method for collecting a component member from a used absorptive article 1 which has a surface sheet 2, a rear face sheet 3, and an absorber 4 arranged between the surface sheet and the rear sheet, where at least one of the surface sheet and the rear sheet contains a film as a component member and the absorber contains an absorber material as a component member. The method includes: a pretreatment step S1 of immersing the used absorptive article in water, and swelling the article; a decomposition step S2 of giving a physical impact to the swelled used absorptive article, and decomposing the used absorptive article into at least a film and an absorber material; and a separation step S3 of separating the decomposed film and the absorber material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of recovering a component from a used absorbent article.

  Techniques for recycling absorbent articles such as used disposable diapers are known. For example, Patent Document 1 discloses a method of reusing used disposable diapers. This method comprises the steps of: breaking used disposable diapers into pieces; inserting the broken disposable diapers into a disassembling drum; and inserting the dispensed disposable diapers into pulp components (including a polymer) with a disassembling drum. And c. Decomposing the pulp component into pulp components and separating the disintegrated pulp components and non-pulp components from each other. In the disassembling step, when the broken paper diaper is put into the decomposition drum into which industrial water or seawater is injected, the broken paper diaper is in a broken state by a plurality of projections provided on the inner surface of the rotating decomposition drum. It is decomposed into pulp and non-pulp components. Non-pulp components are recycled as recycled resin and the like. In the pulp component, the polymer is broken into fine particles in a grinder and discarded, and the pulp is recovered.

JP, 2010-59586, A

  In patent document 1, when disassembling a used disposable diaper into a pulp component and a non-pulp component, a disposable diaper is broken in advance into a plurality of small pieces (pieces). However, when the disposable diaper is broken into a plurality of pieces, chips and chips may occur at the broken portion of each piece. In particular, used absorbent articles are discarded in a rolled-up or folded-up state with the top sheet inside so that the excrement is not exposed to the front side and the odor is not diffused to the surroundings. That's normal. Therefore, in the used absorbent article, since the position to be broken and the shape of the broken part are not constant, the tendency of chips and the like is high. Furthermore, when such a plurality of small pieces are disassembled by the disassembling drum, chips and the like may be further generated from broken portions of the small pieces due to the impact of the rotation of the disassembling drum. Since the chips and the like are mixed in the drainage, it is difficult to recover the chips and the like. In addition, as the size of each small piece is smaller, the size of the pulp component and the size of the non-pulp component contained in the small pieces become equivalent to each other and it becomes difficult to distinguish between them, which may make it difficult to separate the components. There is. As a result of these, the recovery rate of components such as films in disposable diapers, ie, absorbent articles, is reduced.

  A top sheet, a back sheet, and an absorber disposed between the top sheet and the back sheet, wherein at least one of the top sheet and the back sheet includes a film as a component, and the absorber is a component As a method of recycling a component of a used absorbent article containing an absorbent material, it is possible to efficiently recover the component from the used absorbent article without breaking the used absorbent article. provide.

  The method of recovering the component from the used absorbent article in the present invention is as follows. (1) A top sheet, a back sheet, and an absorber disposed between the top sheet and the back sheet, wherein at least one of the top sheet and the back sheet includes a film as a component member, A method of recovering the component from the used absorbent article wherein the absorber comprises an absorbent material as a component, wherein the used absorbent article is pre-treated to swell the used absorbent article with water. Of subjecting the used absorbent article to physical impact to decompose the used absorbent article into at least the film and the absorbent material, and separating the disassembled film and the absorbent material And a separating step.

In this method, in the pretreatment step, the used absorbent article is absorbed into water in the form as it is without breakage or the like, and without inactivation of the superabsorbent polymer. Therefore, water can be absorbed to the used absorbent article to an amount close to the maximum absorption of the used absorbent article (example: 80% by mass or more of the maximum absorption). That is, the used absorbent article can be in a very expanded state with water. As a result, the used absorbent article has a very high internal pressure. Due to the internal pressure, the used absorbent article can be made in the water from the rolled-up state or the folded-up state when discarded, to the flat-deployed state. At this time, since the used absorbent article is very expanded, any part of its surface is likely to be broken.
Then, in the disassembly process, physical impact, eg, lifting up from the base, onto the used absorbent article in a state where such expanded and flat and any part of the surface is likely to tear off due to expansion, Impact is applied in such a manner as to fall downward and repeat the impact to the base. As a result, the used absorbent article which is likely to tear off any part of 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 be spouted (jump out) through the. Thereby, the used absorbent article can be decomposed at least into a film and an absorbent material. At this time, the film generally maintains substantially the same shape as that of the absorbent article, that is, the original shape except for partial cracks and the like. Therefore, the size, shape, and mass of the film are clearly different from the size and shape of the absorber material as compared to the case where they are broken into fragments before decomposition, and the film is absorbed even in the subsequent separation step. It can be easily separated from body material.
Thus, a component such as a film can be separated from the other components without breaking or the like and maintaining its shape as it is. Therefore, components such as the film of the absorbent article can be efficiently recovered.

In the method, (2) the absorbent material includes a superabsorbent polymer and pulp fibers, and the separating step is performed with an aqueous solution containing an inactivating agent before separating the film and the absorbent material. A step of deactivating the superabsorbent polymer, the film, and a mixture comprising the pulp fibers, the superabsorbent superabsorbent polymer which has been inactivated, and wastewater discharged from the superabsorbent polymer due to inactivation. And the separating step may be the method according to (1) above.
The superabsorbent polymer prior to inactivation is in a highly viscous state and may not be easily separated from the film. Therefore, in the present method, before separating the film and the absorbent material, the superabsorbent polymer is inactivated to dehydrate the superabsorbent polymer. 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 comprising pulp fibers. Therefore, components such as the film of the absorbent article can be efficiently recovered.

The method comprises the steps of: (3) inserting the swollen used absorbent article into the horizontal rotary drum, rotating the rotary drum, and inserting the used absorbent article into the horizontal direction. It lifts from the lower lower region to the upper upper region in the vertical direction in the rotating drum 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 step of applying physical impact to the used absorbent article by causing the method to be described in the above (1) or (2).
In this method, the physical impact on the used absorbent article is achieved by using a horizontal rotary drum (example: rotary drum of a washing tub of a horizontal washing machine) rotating around a virtual rotary axis extending in the horizontal direction. 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 lowered from the upper area to the lower area by gravity. The impact can be applied to the used absorbent article by colliding with the inner surface of the lower region. And, by continuing the rotation of the rotating drum, it is possible to stably, continuously and easily apply the impact caused by such a collision. Thereby, it is possible to stably tear off (peel off) the junction between the top sheet (nonwoven fabric or film) and back sheet (film) in the used absorbent article, and the used absorbent article as a film and an absorbent material Can be disassembled more reliably.

The method according to any one of the above (1) to (3), wherein (4) the pre-treatment step includes the step of swelling the used absorbent article with the water at 70 ° C. or more and 98 ° C. or less. It may be the method described.
In this method, by setting the temperature of water to 70 ° C. or more, the adhesive for bonding the film and other members can be softened by the heat of 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 be made to absorb the water reliably. By these, it is possible to more reliably generate a state in which the surface is likely to be broken due to expansion and to generate a state in which the bonding strength of the adhesive is reduced. Therefore, in the disassembly process, the junction between the top sheet (nonwoven fabric or film) and back sheet (film) with reduced bonding strength is torn (peeled off), and the absorbent material inside the used absorbent article is torn. Can be spouted out through the Thereby, the used absorbent article can be more reliably decomposed at least into the film and the absorbent material. In addition, sterilization is extremely important in reuse of a used absorbent article. By setting the temperature of water to 70 ° C. or higher, it is also possible to exert the effect of sterilization (disinfection).

The method according to the above (1), wherein the pretreatment step includes the step of absorbing the water in an amount of 90% by mass or more of the maximum absorption amount of the used absorbent article into the used absorbent article. The method according to any one of (1) to (4) may be used.
In this method, the step of pre-processing includes the step of causing the used absorbent article to absorb 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 inflated with water. As a result, the used absorbent article can generate extremely high internal pressure. Due to the internal pressure, in the disassembly process, the physical impact applied to the used absorbent article more reliably tears (peeling off) the junction between the top sheet (nonwoven fabric or film) and the back sheet (film) ), The absorbent material inside the used absorbent article can be ejected (popped out) through the crevice.

In the method, (6) the separating step includes the step of removing the adhesive at the joint portion with a solvent which dissolves the adhesive at the joint portion between the film and the other member. It may be a method according to any one of 5).
In this method, since the adhesive at the joint portion between the film (example: film of back sheet) and the other member (example: film or nonwoven fabric of top sheet or absorbent material) is removed by a solvent, the film and the other member Can be separated from one another while maintaining their shape without breaking or the like. Therefore, components such as the film of the absorbent article can be efficiently recovered. Also, the film and the other members can be separated without leaving an adhesive on the film. Thereby, the film can be made reusable as a high-purity resin, and the adverse effect of the adhesive can be suppressed when the film is reused.

The method according to the above (6), wherein (7) the solvent comprises at least one terpene selected from the group consisting of terpene hydrocarbons, terpene aldehydes and terpene ketones.
In this method, the adhesive can be dissolved and removed more reliably by using terpene as a solvent for dissolving the adhesive. Furthermore, since terpene has a high oil stain cleaning effect, if there is another oil component (example: printing ink) in the used absorbent article, the oil component can be decomposed and removed. Thereby, the film can be reused as a high purity resin.

The method according to (6) or (7), wherein the separation step (8) includes the step of drying the film by heating to remove the solvent after the step of removing the adhesive at the joint portion. It may be the method described in
Sterilization is extremely important in the reuse of used absorbent articles. In this method, the separated film is heated and dried, that is, dried by a high temperature atmosphere or hot air, not only the solvent remaining on the surface of the film is removed by evaporation, but also the film is heated by a high temperature atmosphere or hot air It can sterilize. As a result, it is possible to exert the effect of sterilization (disinfecting) while removing the solvent, and it is possible to efficiently recover the component such as the film of the absorbent article.

The method comprises the steps of: (9) separating the pulp fibers from the separated mixture; and treating the separated pulp fibers with an aqueous solution containing an oxidizing agent to separate the pulp fibers. The method according to the above (2), which comprises the steps of reducing the molecular weight of the remaining superabsorbent polymer, and solubilizing and removing it.
In this method, since the superabsorbent polymer remaining in the pulp fibers can be solubilized and removed by oxidation with an oxidizing agent (example: ozone), it is possible to recover highly pure pulp fibers having a low superabsorbent polymer content. Therefore, the components of the absorbent article can be recovered efficiently.

(10) The method according to the above (1) to (9), wherein the used absorbent article is at least one selected from the group consisting of a disposable diaper, a urine absorbing pad, a sanitary napkin, a bed sheet and a pet sheet. The method according to any one of the above.
In this method, at least a disposable diaper, a urine absorbing pad, a sanitary napkin, a bed sheet, and a pet sheet can be used as a used absorbent article.

  According to the method of the present invention, when recycling a component of a used absorbent article, a component such as a film is efficiently recovered from the used absorbent article without breakage or the like of the used absorbent article. It becomes possible.

5 is a flow chart illustrating an embodiment of the method of the present invention. It is a schematic diagram which shows the example of the state change of the used absorbent article in the pre-processing process of FIG. It is a schematic diagram which shows the example of the decomposition | disassembly method in the decomposition | disassembly process of FIG. It is a schematic diagram which shows the example of the used absorbent article decomposed | disassembled in the decomposition | disassembly process of FIG.

  Hereinafter, the method to collect | recover a structural member from the used absorbent article which concerns on embodiment of this invention is demonstrated. However, a used absorbent article is an absorbent article used by the user, and is usually an absorbent article in the state where it absorbed the excrement of the user's liquid. However, in the present embodiment, the used absorbent articles include those used but not absorbing excrement and those not used.

  The structural example of an absorbent article is demonstrated. The absorbent article comprises a top sheet, a back sheet, and an absorber disposed between the top sheet and the back sheet. The absorbent articles include, for example, disposable diapers, urine absorbing pads, sanitary napkins, bed sheets, and pet sheets. The top sheet, the back sheet, and the absorber are formed of components such as non-woven fabric, film, pulp fiber, super absorbent polymer, etc., and they are bonded to each other by an adhesive or the like. 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.

  As a structural member of a surface sheet, a nonwoven fabric or a film is mentioned, for example, Specifically, a liquid permeable nonwoven fabric, a synthetic resin film which has a liquid penetration hole, these composite sheets, etc. are mentioned. As a structural member of a back surface sheet, a nonwoven fabric or a film is mentioned, for example, Specifically, a liquid impervious nonwoven fabric, a liquid impervious synthetic resin film, and a composite sheet of these nonwoven fabrics and a synthetic resin film are mentioned. 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). Among these, polyethylene is preferable.

  In the present embodiment, at least one of the top sheet and the back sheet of the absorbent article includes a film as a component, but in the following, the component of the back sheet is a film and the component of the top sheet is a nonwoven fabric An absorbent article to be used will be described as an example.

  The back sheet may include a breathable exterior sheet on the side opposite to the absorber in the thickness direction. As a component of an exterior sheet, the same component as a back surface sheet can be used. The exterior sheet is adhesively bonded to the back sheet. Furthermore, the top sheet may include water-repellent side sheets on both sides in the width direction. As a structural member of a side sheet, the nonwoven fabric which gave the water-repellent process, and the synthetic resin film which has air permeability are mentioned. The side sheets are adhesively bonded to the top sheet. In the present embodiment, when the absorbent article includes an exterior sheet or a side sheet, the film may include an exterior sheet or a side sheet.

  In the case of imparting liquid permeability or air permeability to the film which is the above-mentioned constituent member, that is, in the case of making the film porous, a filler (inorganic filler) may be contained in the film. Thus, due to the peeling that occurs at the interface between the resin of the film and the filler, a large number of holes are formed in the film. The material of the filler is not particularly limited as long as it can be used as an absorbent article, but for example, 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 formability and stretchability of the material for the film, and the moisture permeability, air permeability, strength and the like of the obtained porous film can be controlled by the content of the filler in the material for the film.

  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. 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.

  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 and the like.

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

  FIG. 1 is a flow chart showing one embodiment of a method for recovering a component from a used absorbent article. The present method comprises a pretreatment step S1 of swelling the used absorbent article with water, and physical impact on the swollen used absorbent article to make the used absorbent article 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 recovered as it is from outside, that is, it is not broken or cut, and if it is in a rolled or folded state (as it is) That is, water is absorbed and swelled as it is in its original shape) and without deactivating the superabsorbent polymer of the absorbent. However, in the present embodiment, the used absorbent article is made to absorb warm water and swell it, or after absorbing and expanding water, the absorbed water is heated to be warm water. Hot water refers to water at a temperature higher than normal temperature (20 ° C. ± 15 ° C. (5 to 35 ° C.): JIS Z 8703).

  Usually, the amount of liquid excrement actually absorbed in the used absorbent article is very small compared to the maximum absorption that the absorbent article can absorb (example: about 10 to 20 of the maximum absorption) mass%). In the present embodiment, in the pretreatment step S1, by immersing the used absorbent article in warm water, water is brought up to an amount close to the maximum absorption of the used absorbent article (example: 80% by mass or more of the maximum absorption) Absorb Alternatively, the used absorbent article is immersed in water at ordinary temperature, and after absorbing water to an amount close to the maximum absorption amount of the used absorbent article, the entire used absorbent article is heated to the temperature of hot water. Thereby, the used absorbent article can be in a state of being greatly expanded with warm water or normal temperature water (hereinafter, also simply referred to as “warm water”). As a result, the used absorbent article has a very high internal pressure. The purpose of making water warm is mainly to weaken the adhesive strength of the adhesive as described later.

  FIG. 2: is a schematic diagram which shows an example of the state change of the used absorbent article in pre-processing process S1 of FIG. However, FIG. 2 (a) shows the state of the used absorbent article before soaking in warm water and FIG. 2 (b) after soaking in warm water. As shown in FIG. 2 (a), the used absorbent article 1 is initially in a rolled or folded state with the back sheet 3 on the outside (with the top sheet 2 hidden inside). When the used absorbent article 1 in that state is immersed in warm water, the absorbent body 4 of the used absorbent article 1 absorbs the warm water in the warm water and expands. As a result, the internal pressure of the used absorbent article 1 is increased. And by the internal pressure, a force to open the used absorbent article 1 is exerted. As a result, as shown in FIG. 2 (b), the used absorbent article 1 in a rolled or folded state is generally flat so as to open outward and expose the top sheet 2. become. That is, the used absorbent article 1 can be spread flat in warm water. At this time, in the used absorbent article 1, the absorbent body 4 absorbs a large amount of warm water and is very expanded, so either the front sheet 2 or the back sheet 3 wrapping the absorbent body 4 is used. It is likely to be broken easily. That is, by the pretreatment step S1, the used absorbent article can be in a state in which any surface is likely to be torn or broken. When the used absorbent article 1 is in a flat state from the beginning, any part of the surface is likely to be easily broken as it is. This state can not occur when the used absorbent article of Patent Document 1 is broken or the like.

  Furthermore, the used absorbent article is soaked in warm water and / or absorbs warm water to soften the adhesive (example: hot melt adhesive) used for bonding between respective components by the heat of warm water. Can reduce the bonding strength of the adhesive. For example, the adhesive for bonding the peripheral portion of the top sheet and the peripheral portion of the back sheet can be softened by the heat of warm water to reduce the bonding strength of the adhesive. Furthermore, the adhesive for bonding the top sheet to the absorber and the adhesive for bonding the back sheet to the absorber can be softened by the heat of warm water to reduce the bonding strength of these adhesives.

  As described above, in the pretreatment step S1, any part of the surface of the used absorbent article is likely to peel off due to the expansion of the absorbent of the used absorbent article, and the bonding strength of the adhesive is reduced. The state can be generated. When the used absorbent article is in such a state, the used absorbent article can be reliably disassembled in the decomposition step described later.

  Moreover, 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, and for example, 60 ° C. or more is mentioned, preferably 70 ° C. or more and 98 ° C. or less. In other words, the pretreatment step S1 preferably includes a step of swelling the used absorbent article with warm water of 70 ° C. or more and 98 ° C. or less. An adhesive for bonding a film (in the present embodiment, a back sheet) and another member (in the present embodiment, a nonwoven fabric of a surface sheet or an absorbent material of an absorbent) by setting the temperature of hot water to 70 ° C. or higher Can be further 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 hot water to 98 ° C. or less, the hot water is surely present as a liquid, so that the used absorbent article can more reliably absorb the hot water. The expansion of the absorbent body and the heat of the hot water can more reliably generate a state in which the surface of the used absorbent article is likely to be broken and a state in which the bonding strength of the adhesive is reduced. The temperature of the hot water is more preferably 75 ° C. or more and 90 ° C. or less, still more preferably 75 ° C. or more and 85 ° C. or less. For the measurement of temperature, measure the temperature of warm water in which the used absorbent article is immersed, or the temperature 5 mm inside from the surface of the used absorbent article which absorbed water to an amount close to the maximum absorption ( Measure the tip of the temperature sensor).

  Moreover, sterilization of a constituent material is very important in reuse of a used absorptive article. By setting the temperature of the hot water to 70 ° C. or higher, it is possible to exert the effect of sterilizing (disinfecting) the used absorbent article, which is preferable.

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

  The amount of absorption of warm water 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 can be decomposed in the decomposition step described later. 80 mass% or more of maximum absorption amount is mentioned, Preferably it is 90 mass% or more. In other words, the pretreatment step S1 preferably includes a step of absorbing the warm water (water) in an amount of 90% by mass or more of the maximum absorption amount of the used absorbent article in the used absorbent article. Thereby, the used absorbent article can be fully inflated with water. As a result, an extremely high internal pressure can be generated in the absorbent of the used absorbent article. Due to the extremely high internal pressure, the used absorbent article can be developed into a flat state very easily if the used absorbent article is in a folded state or the like. At the same time, the expansion of the absorber can more reliably generate a state in which the surface of the used absorbent article is likely to tear. As a result, it is possible to disassemble the used absorbent article more reliably by the physical impact applied to the used absorbent article in the later-described decomposition process.

Here, the maximum absorption is measured by the following procedure.
(1) The unused absorbent article is subjected to drying treatment in an atmosphere of 100 ° C. or higher, and the mass of the absorbent article is measured.
(2) When an elastic material (for example, an elastic member around a leg or a waist) that can form a pocket that makes it difficult for water to reach the absorbent body is disposed in the absorbent article, the elastic member is notched Level the absorbent article.
(3) Immerse the absorbent article with the top sheet down in a water bath filled with sufficient tap water and leave it for 30 minutes.
(4) After standing, the absorbent article is placed on the mesh with the top sheet facing down, drained for 20 minutes, and then the mass of the absorbent article is measured.
And the mass difference before and behind immersion in tap water is defined as maximum absorption.

  Furthermore, in all used absorbent articles, the weight per used absorbent article is substantially the same in all used absorbent articles by absorbing warm water up to approximately the maximum absorption amount of the used absorbent articles. (If the type of used absorbent article is the same). Therefore, by dividing the weight of all the used absorbent articles at that time by the weight per used absorbent article at that time, the recovered used absorption which was unknown at the time of recovery of the disposable absorbent articles The total number of sexual goods can be estimated. Thereby, the recovery amount of each component can be roughly estimated. For example, the number of films to be recovered and the amount of adhesive to be treated can be estimated from the total number of used absorbent articles recovered. Therefore, in the process after the pre-processing process S1, the amount of the processing liquid etc. when processing each component individually can be easily estimated and can be easily adjusted.

  Then, the decomposition step S2 gives physical impact to the used absorbent article expanded and swollen in the pretreatment step S1, and at least the film (back sheet) and the absorbent material (absorbent body) are used. And disassemble. In the present embodiment, the film is decomposed into a film (back sheet) and a nonwoven fabric (top sheet) and an absorber material (absorber).

  The used absorbent article is unfolded and flat by the pretreatment step S1, and any part of the surface is likely to tear off due to expansion, and in the present embodiment, the adhesive particularly due to the heat of warm water The bonding strength of the is reduced. Therefore, by applying physical impact to the used absorbent article in that state in the disassembling step S2, a surface sheet (nonwoven fabric) and a back surface sheet (in particular, with reduced bonding strength) at any point on the surface. The joint with the film is broken. Thereby, the joint portion can be torn off. The physical impact is not particularly limited, but, for example, the method of striking the used absorbent article on a surface made of a material harder than the used absorbent article, or the used absorbent articles are disposed facing each other There is a method of pressing from both sides while passing between a pair of rolls while passing. In addition, even if the water for immersing the used absorbent article in the pretreatment step S11 is normal temperature, the used absorbent article can be expanded to make the surface be likely to be broken, and the used absorbability in the decomposition step S12 It is possible to tear away a used absorbent article anywhere on the surface, even when the atmosphere that impacts the article is at ambient temperature.

  In the present embodiment, the following method which is an example of a method of striking a used absorbent article on a surface made of a material harder than the used absorbent article is employed. FIG. 3 is a schematic view showing an example of the decomposition method in the decomposition step S2 of FIG. Fig.3 (a)-FIG.3 (c) show the method of applying a physical impact to the used absorbent article 1. As shown in FIG. That is, the disassembling step S2 is a charging step of charging the swollen used absorbent article 1 into the rotary drum 20, and an impact of rotating the rotary drum 20 to give a physical impact to the used absorbent article 1. And a process.

  As shown in FIG. 3A, the rotary drum 20 is a horizontal rotary drum that rotates around an imaginary rotation axis A extending in the horizontal direction HD. Examples of the rotary drum 20 include a rotary drum of a washing tub of a horizontal washing machine, and thus the disassembling step S2 can be carried out using a horizontal washing machine. For example, ECO-22B manufactured by Inamoto Seisakusho Co., Ltd. can be used as the horizontal washing machine. 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. The lower area LA is preferably an area of D / 3 below the vertical direction VD of the rotary drum 20, and more preferably an area of D / 4, where the inner diameter of the rotary drum 20 is D. The upper region UA is preferably a region of D / 3 above the vertical direction VD in the rotary drum 20, and more preferably a region of D / 4. The inner diameter D × depth may be, for example, 50 to 150 cm × 30 to 120 cm.

  In the charging step, as shown in FIG. 3A, the used absorbent article 1 is placed on the inner surface of the rotary drum 20 in the lower area LA. At this time, the number of used absorbent articles 1 placed is such an amount that can sufficiently impact the used absorbent article 1 in the impact step, and is at most within the lower area LA. It is a number. If the number is too large, the movement of the used absorbent article in the rotating drum 20 will be small, and the used absorbent article can not be impacted.

  In the subsequent impact step, as shown in FIG. 3B, the rotary drum 20 is rotated to lift the used absorbent article 1 from the lower area LA in the rotary drum 20 to the upper area UA. Then, as shown in FIG. 3C, the used absorbent article 1 is lowered from the upper area UA to the lower area LA by gravity and collides with the inner surface of the rotary drum 20 in the lower area LA. Such a process can give physical impact to the used absorbent article 1.

  The rotational speed of the rotary drum 20 is not particularly limited as long as the impact process can be realized, and may be, for example, 30 times / min to 100 times / min. Further, although the temperature of the used absorbent article 1 is kept relatively high by the warm water absorbed in the used absorbent article 1, the viewpoint of suppression of temperature decrease of the adhesive and maintenance of the effect of sterilization Therefore, 70 degreeC or more is preferable, and, as for the temperature of the atmosphere in the rotating drum 20, 75 degreeC or more is more preferable. The temperature in the rotating drum 20 is preferably 98 ° C. or less, more preferably 90 ° C. or less, from the viewpoint of handling of the used absorbent article 1. It is preferable that the amount of water in the rotary drum 20 be as small as possible, and at least as small as possible so that the used absorbent article 1 does not go below the water surface in the impact step. When the used absorbent article 1 is below the water surface, the impact on the used absorbent article 1 is absorbed by water, making it difficult to impart the desired impact to the used absorbent article 1.

  The processing time in the impact step, that is, the time for rotating the rotary drum 20 is not particularly limited as long as the top sheet 2 and the back sheet 3 and the absorber material can be disassembled, and is, for example, 2 to 40 minutes. , Preferably 4 to 20 minutes.

  FIG. 4: is a schematic diagram which shows an example of the used absorbent article 1 decomposed | disassembled by the decomposition | disassembly process of FIG. The used absorbent article 1 is torn off by tearing off the joint portion between the top sheet 2 (non-woven fabric) and the back sheet 3 (film) by physical impact. At the same time, the absorbent material (pulp fiber 8 and the water-absorbent polymer 6) in the used absorbent article 1 spouts out (jumps out) through the crevice 10 by the internal pressure of the absorbent 4 . Thereby, the used absorbent article 1 can be decomposed into the top sheet 2 (non-woven fabric) and the back sheet 3 (film), and the absorbent material (pulp fiber 8 and the water absorbing polymer 6).

  In the present embodiment, in particular, impact is applied to the used absorbent article 1 by striking the used absorbent article 1 from the upper area UA to the lower area LA by gravity using the horizontal rotary drum 20. Can be given. And, by continuing the rotation of the rotary drum 20, such an impact can be stably, continuously and easily applied. As a result, the junction between the top sheet 2 (non-woven fabric) and the back sheet 3 (film) in the used absorbent article 1 can be more stably torn off (peeled off), and the used absorbent article 1 is absorbed with a film It can be reliably disassembled with the body material. Also, existing washing machines can be used.

  Next, the separation step S3 separates the disassembled film (back sheet) and the absorbent material (pulp fibers and water absorbing polymer). In the present embodiment, a plurality of films (back sheet) and a plurality of non-woven fabrics (top sheet) are separated from an absorbent material (pulp fibers and a water absorbing polymer). However, the non-woven fabric may be bonded to the film. At this time, the top sheet (nonwoven fabric) and the back sheet (film) generally maintain the same shape as that of the absorbent article, that is, the original shape. Therefore, the size, shape, and mass of the top sheet (nonwoven fabric) and the back sheet (film) are clearly different from the size and shape of the absorber material, as compared to the case where they are broken into fragments before decomposition. Therefore, in the separation step S3, the top sheet (nonwoven fabric) and the back sheet (film) can be easily separated from the absorbent material (pulp fibers and water absorbing polymer). As the separation method, for example, a method using a sieve which passes the absorbent material without passing through the top sheet and the back sheet can be mentioned. As a result, a component such as a film can be separated from other components while maintaining its shape without breaking or the like. Therefore, components such as the film of the absorbent article can be efficiently recovered.

  In the present embodiment, the separation step S3 includes an inactivation step S31 in which the superabsorbent polymer is inactivated with an aqueous solution containing an inactivating agent, and a film and pulp fibers before the film and the absorbent material are separated. A first separation step S32 of separating the inactivated superabsorbent polymer and the mixture containing the waste water discharged from the superabsorbent polymer by inactivation may be included.

  In the inactivation step S31, before the first separation step S32, the top sheet (non-woven fabric), the back sheet (film), and the absorbent material (pulp fibers and super absorbent polymer) can be inactivated the super absorbent polymer In an aqueous solution containing the Thereby, the superabsorbent polymer adhering to the top sheet, the back sheet and the pulp fibers can be inactivated. Thus, the highly water-absorptive polymer in a high viscosity state can be dewatered by inactivation to a highly water-absorptive polymer in a low viscosity state before inactivation.

  Here, the inactivating agent is not particularly limited, and 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 in pulp fibers. When using an inorganic acid or an organic acid as the inactivating agent, the pH of the inorganic acid aqueous solution or the organic acid aqueous solution is 2.5 or less, preferably 1.3 to 2.4. Therefore, the aqueous solution containing the inactivating agent can be referred to as an acidic aqueous solution. When 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, there is a risk of corrosion of the equipment, and a large amount of alkali chemicals are required for neutralization treatment during wastewater treatment. 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. On the other hand, examples of the organic acid include citric acid, tartaric acid, glycolic acid, malic acid, succinic acid, acetic acid, ascorbic acid and the like, with citric 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. 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% by mass or more and 0.5% or more. It is less than mass%. 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 treatment temperature in the inactivation step S31, that is, the temperature of the aqueous solution containing the inactivating agent is not particularly limited as long as the inactivation reaction proceeds. The treatment temperature may be room temperature or may be higher than room temperature, and includes, for example, 15 to 30 ° C. Further, the treatment time of the inactivation step S31, that is, the time for immersing the top sheet, the back sheet and the absorbent material in an aqueous solution containing an inactivating agent is not particularly limited as long as the superabsorbent polymer is inactivated and dehydrated. For example, 2 to 60 minutes are mentioned, Preferably it is 5 to 30 minutes. Further, 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, for example, preferably 300 to 3000 parts by mass, more preferably 500 to 2500 parts by mass, and still more preferably 1000 to 2000 parts by mass with respect to 100 parts by mass of the used absorbent article.

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

  In the first separation step S32, the method for separating the top sheet and the back sheet, the pulp fibers, the superabsorbent polymer and the sewage is not particularly limited. For example, the product (front sheet, back sheet, pulp fiber, super absorbent polymer, waste water, etc.) generated by the inactivation step is discharged through a screen with an opening of 5 to 100 mm, preferably 10 to 60 mm. . As a result, the pulp fibers, the superabsorbent polymer and the sewage can be separated during drainage while the top and back sheets remain on the screen to separate the products. Other large shapes such as non-woven fabric and film may remain on the screen. In particular, since the superabsorbent polymer is in a high viscosity state prior to inactivation, it is not easy to separate the superabsorbent polymer attached to the top sheet, back sheet and pulp fibers. However, after deactivation, the superabsorbent polymer is in a low viscosity state by dehydration, so the superabsorbent polymer attached to the topsheet, backsheet and pulp fibers can be removed from the topsheet, backsheet and pulp fibers. It can be easily separated. Therefore, the components of the absorbent article can be efficiently separated and recovered.

  In the present embodiment, the separation step S3 may further include a second separation step S33 in which the adhesive in the joint portion is removed by a solvent that dissolves the adhesive in the joint portion between the film and the other member. In this embodiment, the adhesive in each bonding portion is removed by a solvent that dissolves the adhesive in each bonding portion between the film, the non-woven fabric, and the absorber material.

  In the second separation step S33, the adhesive of the bonding portion between the film (rear sheet) and other members (non-woven fabric of the front sheet, absorbent material of the absorbent sheet remaining on the front sheet or rear sheet, etc.) Remove by As a result, the film and the other members can be separated from each other without breaking or the like while maintaining the shape as it is. Therefore, components such as the film of the absorbent article can be efficiently recovered. In addition, since the film and the other members can be separated without leaving an adhesive on the film, the film can be reused as a resin with high purity. Thereby, it is possible to suppress the adverse effect of the adhesive when the film is reused. The non-woven fabric is also similar to the film.

  The solvent used in the second separation step S33 is not particularly limited as long as it can dissolve the adhesive, but, for example, terpene containing at least one of terpene hydrocarbon, terpene aldehyde and terpene ketone It can be 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. Preferably, it is 0.075 to 1% by mass. If the concentration of terpene is too low, it may not be possible to dissolve the adhesive at the joints. If the concentration of terpene is too high, the cost may be high. In addition to dissolving adhesives such as hot melt adhesives, Tempel also has an oil stain cleaning effect. Therefore, for example, when there is printing on a component of the absorbent article such as a back sheet, the tempel can decompose and remove the printing ink.

  The terpene hydrocarbons include, for example, myrcene, limonene, pinene, camphor, sapinene, ferandrene, paracymene, ocimene, terpinene, carene, zingiberene, caryophyllene, bisabolene, cedrene. Among them, limonene, pinene, terpinene and carene are preferable. Examples of terpene aldehydes include citronellal, citral, cyclocitral, safranal, ferandral, perylaldehyde, geranial and neral. Examples of terpene ketones include camphor and tsuyoshi. Among the terpenes, terpene hydrocarbons are preferred, and limonene is particularly preferred. There are three types of limonene, d-limonene, l-limonene, and dipentene (dl-limonene), and any of them can be preferably used. The terpenes can be used alone or in combination of two or more.

  The processing temperature of the second separation step S33, that is, the temperature of the aqueous solution containing the solvent is not particularly limited as long as the dissolution of the adhesive proceeds and the used absorbent article is decomposed into components. The treatment temperature may be room temperature or may be higher than room temperature, and includes, for example, 15 to 30 ° C. In addition, for the processing time of the second separation step S33, that is, the time for immersing the top sheet, the back sheet and the absorber material in an aqueous solution containing a solvent, the dissolution of the adhesive progresses and the used absorbent article is decomposed into components. 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, that is, the amount of the aqueous solution containing the solvent is not particularly limited as long as the dissolution of the adhesive proceeds and the used absorbent article is decomposed into components. The amount of the aqueous solution is, for example, preferably 300 to 3000 parts by mass, and more preferably 500 to 2500 parts by mass with respect to 100 parts by mass of the used absorbent article. By the second separation step S33, the amount of the adhesive remaining in the film, the nonwoven fabric or the absorber material can be made 1% by mass or less with respect to the film, the nonwoven fabric or the absorber material.

  In the present embodiment, as another preferable mode, the second separation step S33 may be performed in the inactivation step S31. That is, while inactivating the superabsorbent polymer attached to the top sheet, back sheet and pulp fiber, the adhesive attached to the top sheet, back sheet and pulp fiber may be dissolved. In this case, an aqueous solution containing both an inactivating agent and a solvent is used as an aqueous solution in which the top sheet, the back sheet, the pulp fibers and the superabsorbent polymer are immersed. Thus, in the inactivation step S31, the back sheet (film), the top sheet (non-woven fabric), and the absorbent body (pulp fibers and super absorbent polymer) can be substantially separated in the aqueous solution. Then, in the subsequent first separation step S32, the back sheet (film) and the surface sheet (non-woven fabric) can be separated from the absorber (pulp fiber and super absorbent polymer), and the second separation step S33 is omitted. it can. In this case, the back sheet (film) and the top sheet (non-woven fabric) are substantially separated by the removal of the adhesive.

  In the present embodiment, in the separation step S3, after the step of removing the adhesive at the bonding portion, the film is dried by heating, that is, dried by an atmosphere or hot air at a temperature higher than room temperature to remove the solvent. Step S34 may be further included. In the present 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, a step of drying the separated film (back sheet) and the non-woven fabric (top sheet) in a high temperature atmosphere or hot air is performed. The drying temperature is, for example, 105 to 210 ° C, preferably 110 to 190 ° C. Although depending on the drying temperature, the drying time is, for example, 10 to 120 minutes, preferably 15 to 100 minutes. Thus, not only the solvent remaining on the surface of the film and the nonwoven fabric is evaporated and removed, but also the film and the nonwoven fabric can be sterilized in a high temperature atmosphere or hot air. As a result, it is possible to achieve the effect of sterilization (disinfecting) while removing the solvent. Therefore, the film and the nonwoven fabric as constituent members of the absorbent article can be efficiently recovered. And, since the film and the non-woven fabric are clearly different in density and properties, they can be easily separated. The recovered film and non-woven fabric can be regenerated, for example, into pellets, respectively, and then further recycled as a plastic bag or film. At this time, the amount of adhesive remaining in the recovered film and non-woven fabric is 1% by mass or less with respect to the film or non-woven fabric, so the amount of adhesive remaining in the pellet, poly bag or film is also relative to the pellet, poly bag or film Can be less than 1% by mass.

  On the other hand, in the present embodiment, in the separation step S3, the third separation step S35 of separating pulp fibers from the separated mixture, and the separated pulp fibers are treated with an aqueous solution containing an oxidizing agent to form pulp fibers. And oxidizing agent treatment step S36 for reducing the molecular weight, solubilizing and removing the remaining superabsorbent polymer.

  In the third separation step S35, the method for separating the pulp fibers from the separated mixture (including pulp fibers, superabsorbent polymer and sewage) is not particularly limited. Discharge while passing through a screen of 1 to 4 mm, preferably 0.15 to 2 mm. As a result, the superabsorbent polymer and the sewage can be separated from the mixture by leaving the pulp fibers (the superabsorbent polymer remaining on the surface) on the screen in the drainage. This pulp fiber is rich in impurities but can be used depending on the application.

  Furthermore, in the oxidizing agent treatment step S36, the inactivated super absorbent polymer remaining on the surface of the separated pulp fiber is oxidatively decomposed by the oxidizing agent, reduced in molecular weight, and solubilized, from the surface of the pulp fiber Remove. Here, the highly water-absorptive polymer is oxidatively decomposed to be reduced in molecular weight, and in a solubilised state means a state of passing through a 2 mm screen. Thereby, impurities such as super absorbent polymers contained in the pulp fibers can be removed to produce pulp fibers with high purity. Moreover, secondary sterilization and bleaching of pulp fibers and deodorization can be performed by oxidizing agent treatment.

  The oxidizing agent is not particularly limited as long as it can oxidatively decompose the inactivated superabsorbent polymer, reduce the molecular weight, and solubilize it, and examples thereof include chlorine dioxide, ozone and sodium hypochlorite. Among them, ozone is preferred 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 bringing a mixture containing pulp fiber and super absorbent polymer into contact with ozone, specifically by blowing ozone into waste water containing pulp fiber and super absorbent polymer. It can be performed. The ozone can be generated, for example, using an ozone water generator (e.g., an ozone water exposure tester ED-OWX-2 manufactured by Ecodesign Co., Ltd., an ozone generator OS-25V manufactured by Mitsubishi Electric Corporation).

  When ozone is blown into waste water containing pulp fiber and super absorbent polymer, the concentration of ozone in the waste water is not particularly limited as long as it is a concentration capable of decomposing the super absorbent polymer, for example, 1 to 50 mass ppm Preferably it is 2-40 mass ppm. If the concentration is too low, the superabsorbent polymer can not be completely solubilized, and the superabsorbent polymer may remain in the pulp fiber. On the other hand, if the concentration is too high, the oxidizing power is also increased, which may damage the pulp fibers and may also cause safety problems. The ozone treatment temperature is not particularly limited as long as it is a temperature at which the superabsorbent polymer can be decomposed, and may be, for example, room temperature or may be higher than room temperature. The ozone treatment time is not particularly limited as long as it is a time capable of decomposing the superabsorbent polymer, and is, for example, 10 to 120 minutes, preferably 20 to 100 minutes. If the ozone concentration is high, it may be short, and if the ozone concentration is low, it will take a long time. When ozone is blown into the effluent comprising pulp fibers and the deactivated superabsorbent polymer, the effluent is preferably acidic. More preferably, the pH of the waste water is 2.5 or less, more preferably 1.5 to 2.4. By treating in the acidic state, the decomposition and removal effect of the superabsorbent polymer by ozone is improved, and the superabsorbent polymer can be decomposed in a short time.

  In the present embodiment, the separation step S3 comprises: a fourth separation step S37 of separating pulp fibers treated with an aqueous solution containing an oxidizing agent from an aqueous solution containing an oxidizing agent; and drying the separated pulp fibers 2 drying step S38 may be included.

  In the fourth separation step S37, the method for separating the pulp fibers from the aqueous solution containing the oxidizing agent is not particularly limited. For example, a treatment liquid containing pulp fibers is passed through a screen having an opening of, for example, 0.15 to 2 mm. There is a way to When a treatment solution containing pulp fibers is passed through a screen with an aperture of 0.15 to 2 mm, drainage containing the product of the oxidative decomposition of the superabsorbent polymer passes through the screen, and the pulp fibers remain on the screen.

  In the subsequent second drying step S38, the pulp fibers treated and separated with the 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. Although depending on the drying temperature, the drying time is, for example, 10 to 120 minutes, preferably 15 to 100 minutes. As a result, the solvent remaining on the surface of the pulp fibers is evaporated and removed, and highly pure pulp fibers with an extremely low superabsorbent polymer content can be recovered. Therefore, the components of the absorbent article can be recovered efficiently. In addition, pulp fibers can be sterilized (disinfected) by a high temperature atmosphere or hot air.

  In the present embodiment, in the pretreatment step S1, the used absorbent article is in a state as it is without breaking or the like, and in a state of being greatly expanded with water without inactivating the super absorbent polymer. be able to. Thereby, a very high internal pressure can be generated in the used absorbent article to make any part of the surface likely to be broken. Then, in the disassembling step S2, a physical impact is applied to the used absorbent article in such a state to cause any part of the surface to be split, and the internal absorbent material is ejected to the outside. It can be done. Thereby, the used absorbent article can be decomposed into at least a film (back sheet) and an absorbent material. At this time, since the film generally maintains its original shape, it can be easily separated from the absorber material in the subsequent separation step S3. Thus, a component such as a film can be separated from the other components without breaking or the like and maintaining its shape as it is. Therefore, the components of the absorbent article can be recovered efficiently.

  In the present embodiment, as a preferable form, by using terpene for removing the adhesive, it becomes possible to dissolve the hot melt adhesive for bonding the constituent members of the absorbent article at normal temperature. As a result, the absorbent article can be easily and cleanly separated, the pulp fibers and the superabsorbent polymer can be separated from the absorbent article, and the non-woven fabric and the film can be separated separately while leaving the form of the member. That is, pulp fibers, films and non-woven fabrics can be easily recovered separately without crushing the absorbent article or going through complicated separation steps. When limonene is used as the terpene, since it has a refreshing citrus odor as a secondary effect of limonene, it is possible to cover up the odor derived from excrement to some extent, and to reduce the burden of odor on workers and the influence of odor on the neighborhood. Because limonene is a monoterpene and similar in structure to styrene, it can dissolve styrenic hot melt adhesives commonly used in absorbent articles. Since the absorbent article can be washed at normal temperature, energy costs can be reduced and generation and diffusion of odor can be suppressed. Terpene has a high oil stain cleaning effect, and in addition to the dissolution effect of the hot melt adhesive, when there is printing on the film, its printing ink can be decomposed and removed, and the printed film can be recovered as a high purity plastic material It is.

  In addition, when an organic acid aqueous solution having a pH of 2.5 or less is used for inactivating superabsorbent polymers, it is difficult to deteriorate pulp fibers. In addition, when citric acid is used as the organic acid, the excrement-derived dirt component removing effect can be expected by the chelating effect of citric acid and the detergency. In addition, a disinfecting effect and a deodorizing effect on alkaline odor can also be expected.

  Furthermore, by decomposing and removing the super absorbent polymer with an oxidizing agent, it is possible to prevent the contamination of the pulp fibers and the rapid increase of the waste water due to the super absorbent polymer water absorption. By adjusting the type and concentration of the oxidizing agent used, it is possible to simultaneously carry out oxidative decomposition and sterilization of the superabsorbent polymer. Also, when no oxidizing agent treatment step is provided or when ozone is used as an oxidizing agent in the oxidizing agent treatment step, no chlorine chemical is used at all, so a high quality material that hardly damages the combustion furnace from recovered plastic members. RPF production is possible. If the films are collected separately, they can be regenerated as materials for bags and films. Since no salts are used in the treatment process, there is no residue on pulp fibers and high-quality pulp with low ash content can be recovered.

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

  The method according to the present embodiment can be suitably used to individually recover constituent members such as a film and an absorbent member from a used absorbent article.

  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 can be appropriately combined or changed without departing from the object and the purpose of the present invention.

1 Spent Absorbent Article 2 Front Sheet 3 Back Sheet 4 Absorber S1 Pretreatment Step S2 Decomposition Step S3 Separation Step

Claims (10)

A front sheet, a back sheet, and an absorber disposed between the top sheet and the back sheet, wherein at least one of the top sheet and the back sheet includes a film as a component, the absorber A method of recovering the component from a used absorbent article comprising an absorbent material as a component,
A pretreatment step of swelling the used absorbent article with water;
A decomposition step of applying physical impact to the swollen used absorbent article to decompose the used absorbent article into at least the film and the absorbent material;
A separation step of separating the decomposed film and the absorber material;
Equipped with
Method. The absorbent material comprises a superabsorbent polymer and pulp fibers,
The separation step is
Before the film and the absorbent material are separated, inactivating the superabsorbent polymer with an aqueous solution comprising an inactivating agent;
Separating the film and a mixture comprising the pulp fibers, the superabsorbent superabsorbent polymer which has been inactivated and the sewage discharged from the superabsorbent polymer due to inactivation;
including,
The method of claim 1. The decomposition step is
Charging the swollen used absorbent article into a horizontal rotary drum;
The rotating drum is rotated to lift the used absorbent article from the vertically lower lower region to the upper upper region in the rotating drum, and the upper region to the lower region by gravity. Applying a physical impact to the used absorbent article by lowering it to collide with the inner surface of the rotating drum in the lower area;
including,
A method according to claim 1 or 2. The pretreatment step includes a step of swelling the used absorbent article with the water at 70 ° C. or more and 98 ° C. or less.
A method according to any one of the preceding claims. The pre-treatment step includes the step of absorbing the water in an amount of 90% by mass or more of the maximum absorption amount of the used absorbent article into the used absorbent article.
5. A method according to any one of the preceding claims. The separation step includes the step of removing the adhesive at the joint portion with a solvent that dissolves the adhesive at the joint portion between the film and the other member.
A method according to any one of the preceding claims. The solvent comprises at least one terpene selected from the group consisting of terpene hydrocarbons, terpene aldehydes and terpene ketones,
The method of claim 6. The separating step includes a step of heat-drying the film to remove the solvent after the step of removing the adhesive at the joint portion.
A method according to claim 6 or 7. Separating the pulp fibers from the separated mixture;
Treating the separated pulp fiber with an aqueous solution containing an oxidizing agent to lower the molecular weight of the superabsorbent polymer remaining in the pulp fiber, and solubilize and remove it;
including,
The method of claim 2. The used absorbent article is at least one selected from the group consisting of a disposable diaper, a urine absorbing pad, a sanitary napkin, a bed sheet, and a pet sheet.
A method according to any one of the preceding claims.

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