Soil improvement method, soil improvement system, absorbent article, and soil improver

Abstract

To provide a technique capable of suppressing an increase in product price due to use of biodegradable materials.SOLUTION: A soil improvement method according to one aspect of the present invention is a soil improvement method using an absorbent article which can absorb a discharged liquid of a wearer, the soil improvement method including: a production step in which a business operator produces an absorbent article including a water-absorbent polymer and a biodegradable nonwoven fabric; a recovery step of recovering a used absorbent article used by a wearer; and a diversion step of diverting the used absorbent article recovered in the recovery step to a farmer as a soil improvement agent for a farmland.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a soil improvement method, a soil improvement system, an absorbent article, and a soil improvement agent. [Background technology]

[0002] Absorbent articles such as disposable diapers, incontinence pads, and sanitary products have been developed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-068464 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, from the viewpoint of environmental protection, attempts have been made to use biodegradable materials in various products. However, the use of biodegradable materials may result in higher raw material costs than conventional materials. Therefore, for daily consumables, such as absorbent articles that can absorb the wearer's excretion, where consumers always demand price control, measures are needed to prevent price increases due to the use of biodegradable materials.

[0005] Therefore, an object of the present invention is to provide a technology that can suppress the increase in product prices that results from the use of biodegradable materials. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention focuses on the fact that human waste and the like are suitable for soil, and uses a biodegradable nonwoven fabric in an absorbent article that can absorb the wearer's excretory fluid, and uses used absorbent articles as soil improvement materials for agricultural land.

[0007] In detail, a soil improvement method according to one aspect of the present invention is a soil improvement method using an absorbent article capable of absorbing liquid excreted by a wearer, and includes a production process in which a business produces absorbent articles containing a water-absorbent polymer and a biodegradable nonwoven fabric, a collection process in which the absorbent articles are collected after use by the wearer, and a conversion process in which the business converts the absorbent articles to be used by farmers as soil conditioners for agricultural land.

[0008] In the soil improvement method according to the above aspect, the recovery step may recover the absorbent articles manufactured by the business operator and used in medical or nursing care facilities used by the wearer.

[0009] In the soil improving method according to the above aspect, the converting step may include selling the absorbent article to the farmer as a soil improver for agricultural soil.

[0010] In the soil improving method according to the above aspect, in the conversion step, at least a portion of the soil to which the soil improver has been sprayed may be further sold to the farmer.

[0011] In the soil improvement method according to the above aspect, in the repurposing step, the absorbent article is applied to the soil at a concentration of 10 to 1000 g / m per area. 2 The particles may be dispersed so as to be in the range of

[0012] In the soil improving method according to the above aspect, the soil contains a substance derived from an animal or a plant. Certain organic substances may be contained.

[0013] In the soil improvement method according to one aspect described above, the production process may include a separation process in which the business produces the absorbent article in which the water-absorbent polymer and the biodegradable nonwoven fabric are arranged on the skin-facing side of a non-permeable back sheet, and the business produces the absorbent article in which the water-absorbent polymer and the biodegradable nonwoven fabric are peeled off from the back sheet to separate the water-absorbent polymer and the biodegradable nonwoven fabric from the collected used absorbent article.

[0014] Furthermore, a soil improvement system according to one aspect of the present invention is a soil improvement system that uses absorbent articles that can absorb liquid excreted by a wearer, and may include a production means by which a business produces absorbent articles that include an absorbent polymer and a biodegradable nonwoven fabric, a collection means by which the business collects the absorbent articles after they have been used by the wearer, and a repurposing means by which the business repurposes the absorbent articles for farmers as soil conditioners for agricultural soil.

[0015] Furthermore, an absorbent article according to one aspect of the present invention comprises a non-permeable back sheet, a water-absorbing polymer that is disposed closer to the skin than the back sheet and is capable of absorbing liquid excretions from the wearer, and a biodegradable nonwoven fabric that is disposed closer to the skin than the back sheet and is capable of receiving excretions from the wearer, and the water-absorbing polymer and the biodegradable nonwoven fabric may be separable from the absorbent article.

[0016] Furthermore, a soil conditioner according to one aspect of the present invention may comprise an absorbent core having a water-absorbent polymer that has absorbed the wearer's excrement, and a biodegradable nonwoven fabric to which the wearer's excrement has adhered.

[0017] In the soil conditioner according to the above aspect, the absorbent core may further include pulp.

[0018] In the soil conditioner according to the above aspect, the pulp content may be 70% or less.

[0019] In the soil conditioner according to the above aspect, the biodegradable nonwoven fabric may contain fibers whose main component is polylactic acid or polybutylene succinate, and the fiber diameter of the biodegradable nonwoven fabric may be 0.1 to 50 denier.

[0020] In the soil conditioner according to the above aspect, the area containing the fibers mainly composed of polylactic acid or polybutylene succinate may have a basis weight of 5 to 100 gsm.

[0021] In the soil conditioner according to the above aspect, the content of the water-absorbent polymer may be 5 to 70%. [Effects of the Invention]

[0022] According to the present invention, a technique can be provided that makes it possible to suppress increases in product prices that result from the use of biodegradable materials. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 illustrates an overview of a soil improvement system according to an embodiment. [Figure 2] FIG. 2 is an example of an external perspective view of a diaper according to an embodiment. [Figure 3] FIG. 3 is an example of an exploded perspective view of a diaper according to an embodiment. [Figure 4] FIG. 4 is an example of a developed view of the diaper according to the embodiment. [Figure 5] FIG. 5 illustrates a schematic of the topsheet and absorbent body separated from a worn diaper. [Figure 6] FIG. 6 is an example of a schematic diagram illustrating how the soil conditioner is spread on the soil and buried. [Figure 7] FIG. 7 illustrates an outline of a soil improvement system according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the configurations of the following embodiments are merely examples, and the present invention is not limited to the configurations of these embodiments.

[0025] [Embodiment] (Outline of the Soil Improvement System 100) FIG. 1 illustrates an overview of a soil improvement system 100 according to an embodiment. In the soil improvement system 100 shown in FIG. 1, a manufacturer 30 purchases biodegradable resin from a raw material manufacturer 85. The manufacturer 30 operates a manufacturing business of diapers 1 containing biodegradable nonwoven fabric. The manufacturer 30 also collects used diapers 1 from medical and nursing care facilities 40. The manufacturer 30 also operates a soil improvement business using the collected used diapers 1. This soil improvement system 100 allows the manufacturer 30 to recover at least a portion of the raw material cost of the biodegradable nonwoven fabric through the soil improvement business. Therefore, the manufacturer 30 can prevent the price of the diapers 1 from increasing due to the use of biodegradable materials. The manufacturer 30 is an example of a "business operator" in the present disclosure, and the owner of the soil 50 is an example of a "farmer" in the present disclosure.

[0026] (Configuration example of soil improvement system 100) FIG. 2 is an example of a perspective view of a diaper 1 manufactured by a manufacturer 30. The diaper 1 is, for example, a pants-type disposable diaper for adults (hereinafter simply referred to as "diaper"). The longitudinal direction of the diaper 1 is the direction connecting the front body portion, which faces the wearer's abdomen, and the back body portion, which faces the wearer's back. The crotch portion, which faces the wearer's crotch (facing the crotch), is located between the front body portion (one side in the longitudinal direction) and the back body portion (the other side in the longitudinal direction) (the center in the longitudinal direction). When the diaper 1 is worn by a wearer, the side facing the wearer's skin is the skin-facing side, and the side opposite the skin-facing side is the non-skin-facing side. The thickness direction is the direction connecting the skin-facing side and the non-skin-facing side, and the direction perpendicular to both the longitudinal direction and the thickness direction is the width direction. The view from the thickness direction is referred to as a plan view. The diaper 1 has a length along the longitudinal direction and a width along a width direction perpendicular to the longitudinal direction, and is worn between the crotch areas of a wearer. Furthermore, terms relating to directions used in this application refer to directions corresponding to the front, back, left, and right of the wearer when the diaper 1 is worn by the wearer. For example, the left-right direction in this application refers to the direction corresponding to the left and right of the wearer when the diaper 1 is worn by the wearer.

[0027] In this embodiment, a tubular pants-type disposable diaper having an opening for the wearer's abdominal circumference and a pair of openings for the wearer's left and right lower legs is exemplified as an example of an absorbent article. However, the "absorbent article" referred to herein is not limited to pants-type disposable diapers for adults. For example, if the medical / nursing care facility 40 in the soil improvement system 100 is a nursery school, the "absorbent article" referred to herein may be pants-type disposable diapers for children. Various types of absorbent articles that can cover the abdominal circumference and crotch area are also included, such as tape-type disposable diapers that form a tubular structure by attaching tape fixed near one end of a sheet-like member that covers the wearer's crotch area (genitals) from the front to the back of the body to the other end of the sheet-like member. Alternatively, the absorbent article may be, for example, an inner pad placed on the top sheet of a diaper.

[0028] As shown in FIG. 2, the diaper 1 has a crotch region 1B, which corresponds to the crotch region covering the wearer's pubic region (crotch area) when worn; a front body region 1F, which corresponds to the front body around the wearer's waist and covers the wearer's abdominal side; and a back body region 1R, which corresponds to the back body around the wearer's waist and covers the wearer's back side. The front body region 1F is located in front of the crotch region 1B, and the back body region 1R is located behind the crotch region 1B. Since the diaper 1 in this embodiment is a pants-type disposable diaper, the left edge of the front body region 1F is joined to the left edge of the rear body region 1R, and the right edge of the front body region 1F is joined to the right edge of the rear body region 1R. Thus, a waist opening 2T is formed in the diaper 1 by the upper edge of the front body region 1F and the upper edge of the back body region 1R. The diaper 1 also has a left leg opening 2L formed in a portion of the left side of the crotch region 1B where the above-mentioned joining is not performed, and a right leg opening 2R formed in a portion of the right side of the crotch region 1B. When the wearer's left leg is inserted through the left leg opening 2L, the wearer's right leg is inserted through the right leg opening 2R, and the wearer's torso is placed within the torso opening 2T, the diaper 1 is secured to the wearer's body with the front body region 1F positioned toward the wearer's abdomen and the back body region 1R positioned toward the wearer's back, and the left leg opening 2L and right leg opening 2R surrounding the wearer's thighs. Because the diaper 1 is secured to the wearer's body in this manner, the wearer can move freely while wearing the diaper 1.

[0029] The diaper 1 has an absorbent body capable of absorbing and retaining liquid, i.e., capable of absorbing the wearer's bodily fluids, positioned mainly near the crotch region 1B. To prevent gaps from forming between the diaper 1 and the wearer's skin, which could serve as a path for liquid leakage, the diaper 1 also has a three-dimensional gather 3BL at the left leg opening 2L surrounding the thigh of the wearer's left lower leg, a three-dimensional gather 3BR at the right leg opening 2R surrounding the thigh of the wearer's right lower leg, and waist gathers 3R and tummy gathers 12 around the wearer's abdominal circumference. Leg gathers 3LL and 3LR are also provided around the base of the wearer's legs. The three-dimensional gathers 3BL and 3BR, waist gathers 3R, and tummy gathers 12 adhere closely to the wearer's skin due to the elasticity of the elastic thread. The leg gathers 3LL and 3LR also prevent gaps from forming between the diaper 1 and the base of the wearer's legs. Therefore, the liquid excreted from the wearer's genitals is absorbed into the absorbent body of the diaper 1 with almost no leakage from the diaper 1.

[0030] FIG. 3 is an exploded perspective view of a diaper 1 according to an embodiment. The diaper 1 comprises a cover sheet 4 and an inner cover sheet 5. The cover sheet 4 and the inner cover sheet 5 are roughly hourglass-shaped (gourd-shaped) sheets that are bonded together to form the outer surface of the diaper 1, and are identical in shape except for the end portion on the front body region 1F side and the end portion on the back body region 1R side. When worn by a wearer, the cover sheet 4 faces away from the wearer's skin, and the inner cover sheet 5 faces the wearer's side. Elastic threads are provided between the cover sheet 4 and the inner cover sheet 5 to form waist gathers 3R, tummy gathers 12, and leg gathers 3LL, 3LR. Elastic members such as strip-shaped elastic can be appropriately selected instead of the elastic threads. It is preferable to use a biodegradable elastomer as the material for the rubber thread, such as a thermoplastic polyurethane elastomer made by blending the following components in a specific blending ratio: polycaprolactone-based copolymer polyol having alkyl side chains in the molecular chain, poly(ethylene-propylene) copolymer polyol, 4,4'-diphenylmethane diisocyanate, and 1,3-propanediol.

[0031] For example, in order to prevent leakage of exudates, the cover sheet 4 and the inner cover sheet 5 can be made of a nonwoven fabric made of a liquid-impermeable thermoplastic resin. Examples of liquid-impermeable thermoplastic resins include resins containing a biodegradable resin as a main component, such as polylactic acid (PLA) and polybutylene succinate (PBS).

[0032] The diaper 1 also has a backsheet 6, an absorbent body 8, and a topsheet 9, which are layered in this order on the wearer-facing surfaces of the coversheet 4 and the inner coversheet 5. The backsheet 6 is a roughly rectangular parallelepiped sheet that extends longitudinally from the front body of the wearer, passing through the crotch area and reaching the back body, and has a predetermined width in the width direction perpendicular to the longitudinal direction. The absorbent body 8 and the topsheet 9 are both sheet-like members with a roughly rectangular appearance, like the backsheet 6, and are layered in this order on the backsheet 6 with their longitudinal directions coinciding with the longitudinal direction of the backsheet 6. The backsheet 6 is a sheet made of a liquid-impermeable thermoplastic resin, such as polylactic acid (PLA) or polybutylene succinate (PBS), to prevent leakage of excrement. The top sheet 9 is placed on the wearer's skin side so as to cover the water-absorbing surface of the absorbent body 8. It is a sheet-like member made of fibers containing a biodegradable resin, such as polylactic acid (PLA) or polybutylene succinate (PBS), as a main component. The fiber diameter of the nonwoven fibers is, for example, about 0.1 to 50 denier. The basis weight of the top sheet 9 is about 5 to 100 gsm. Such a top sheet 9 is liquid-permeable in part or in its entirety. Therefore, when the diaper 1 is worn, liquid excreted by the wearer passes through the top sheet 9, which may come into contact with the wearer's skin, and penetrates into the absorbent body 8, where it is absorbed. Examples of liquid-permeable sheets include woven fabrics, nonwoven fabrics, and porous films. The top sheet 9 may also be hydrophilic.

[0033] The absorbent body 8 has an absorbent core 8c made of one or more mats, and a core wrap sheet 7 that encases the absorbent core 8c. In this embodiment, the absorbent core 8c has an upper absorbent mat 8a and a lower absorbent mat 8b, as shown in Fig. 3. The absorbent core 8c is made of short fibers of cellulosic fibers such as pulp fibers, rayon fibers, or cotton fibers, or short fibers that have been hydrophilized and are made of synthetic fibers containing a biodegradable resin as the main component, such as polylactic acid (PLA) or polybutylene succinate (PBS), and SAP (Super Absorbent Polymer), a hydrophilic polymer with a crosslinked structure that can absorb and retain water, which is filled in the gaps between the short fibers. The absorbent core 8c has a structure that holds granular absorbent resin (polymer absorbent material) such as SAP. When the absorbent core 8c absorbs liquid discharged from the wearer, the absorbent resin held in the gaps between the staple fibers swells to hold the liquid within the staple fibers. The SAP content in the absorbent core 8c is, for example, 5 to 70%. When the absorbent core 8c contains pulp fibers, the pulp fiber content may be, for example, 70% or less. In this embodiment, the upper-layer absorbent mat 8a is generally hourglass-shaped with a narrowed central portion. The absorbent core 8c can have any shape appropriate for the purpose. Examples of the shape of the absorbent core 8c include rectangular, oval, and various other shapes. SAP is an example of the "absorbent polymer" in the present disclosure.

[0034] The core wrap sheet 7 is a thin, liquid-permeable sheet. By wrapping the absorbent core 8c with the core wrap sheet 7, the SAP of the absorbent core 8c described above is less likely to be mixed with other structures. It also prevents the absorbent core 8c from losing its shape. Examples of the core wrap sheet 7 include tissue paper and sheet-like members made of fibers primarily containing biodegradable resins such as polylactic acid (PLA) and polybutylene succinate (PBS). The core wrap sheet 7 may be a single sheet, or it may be composed of two sheets: an upper sheet positioned on the wearer's skin side and a lower sheet positioned on the non-skin-facing side and wrapping around the sides and skin-facing side of the absorbent core 8c. When the core wrap sheet 7 is composed of two sheets, the widthwise edges of the upper sheet may be wrapped in another sheet (e.g., the side sheets 10L and 10R, the back sheet 6, or the top sheet 9, which will be described later). The absorbent body 8 is wrapped in the back sheet 6 and the top sheet 9, and these sheets also help prevent the absorbent body 8 from losing its shape, so the core wrap sheet 7 may not be provided.

[0035] The backsheet 6, the absorbent body 8, and the topsheet 9 all extend from the front body region 1F to the back body region 1R. When these are layered to cover the wearer's genitals (below the crotch), both longitudinal ends of the back sheet 6, absorbent body 8, and top sheet 9 are located on the wearer's ventral and dorsal sides. In other words, the wearer's genitals are covered by the absorbent body 8 from the ventral to the dorsal sides of the wearer. Therefore, whether the wearer is in a ventral or dorsal position when excreting fluid, the excreted fluid comes into contact with the absorbent body 8 via the top sheet 9.

[0036] The diaper 1 also has elongated, strip-shaped side sheets 10L, 10R for forming the above-mentioned three-dimensional gathers 3BL, 3BR. The side sheets 10L, 10R are provided along the long sides of the top sheet 9. Elastic threads 10L1, 10R1 are adhered to the side sheets 10L, 10R along the longitudinal direction. Thus, when the cover sheet 4 is joined at its left edge 4F4 of the front body region 1F to its left edge 4R4 of the back body region 1R, and at its right edge 4F5 of the front body region 1F to its right edge 4R5 of the back body region 1R, the diaper 1 is completed as shown in FIG. 2. The contractile force of the elastic threads 10L1, 10R1 draws the side sheets 10L, 10R in the longitudinal direction, causing them to rise from the top sheet 9 along the fold-back lines 10L2, 10R2. As a result, three-dimensional gathers 3BL, 3BR are formed to prevent liquid from leaking from the left lower leg opening 2L and the right lower leg opening 2R. The joining method of the edges 4F4 and 4R4, and the edges 4F5 and 4R5 is not particularly limited, and can be performed by, for example, heat sealing, high-frequency sealing, ultrasonic sealing, etc. The side sheets 10L, 10R can be made of sheet-like members made of fibers containing biodegradable resin as a main component, such as polylactic acid (PLA) or polybutylene succinate (PBS).

[0037] The diaper 1 further comprises an end sheet 11F laminated on the wearer-facing surface of the cover sheet 4 in the front body region 1F, and an end sheet 11R laminated on the wearer-facing surface of the cover sheet 4 in the back body region 1R, sandwiching the back sheet 6, absorbent 8, top sheet 9, and side sheets 10L and 10R. The end sheets 11F and 11R are strip-shaped sheets laminated on one longitudinal end of the top sheet 9 to the cover sheet 4. The end sheets 11F and 11R are made of impermeable nonwoven fabric and mainly reinforce the cover sheet 4 in the waist-contacting portion of the diaper 1. The end sheets 11F and 11R are positioned closer to the skin than the laminate formed by the back sheet 6, absorbent 8, top sheet 9, and side sheets 10L and 10R, preventing the edges of the laminate from directly contacting the skin and causing discomfort to the wearer. The end sheets 11F and 11R can be made of a sheet-like member made of a fiber containing a biodegradable resin, such as polylactic acid (PLA) or polybutylene succinate (PBS), as a main component.

[0038] FIG. 4 is a schematic diagram showing a diaper 1 according to an embodiment in an unfolded and stretched state. FIG. 4(A) shows the internal structure of the diaper 1 in an unfolded and stretched state as viewed from the left side. FIG. 4(B) shows a schematic plan view of the diaper 1 in an unfolded and stretched state. Note that the side sheets 10L, 10R and end sheets 11F, 11R are not shown in FIG. 4(B). One end of the cover sheet 4 is folded back at the fold lines 4FF, 4RF shown in FIG. 3. The waist gather 3R is formed by adhering elastic threads (thread-like rubber) 4F1, 4F2 to the front body region of the cover sheet 4 and adhering elastic threads (thread-like rubber) 4R1, 4R2 to the back body region of the cover sheet 4.

[0039] The elastic threads 4F1, 4F2 are arranged in this order from the fold line 4FF side along a fold line 4FF (see FIG. 3) that will form the upper edge of the front body region 1F when folded back. Similarly to the elastic threads 4F1, 4F2, the elastic threads 4R1, 4R2 are arranged in this order from the fold line 4RF side along a fold line 4RF that will form the upper edge of the back body region 1R when folded back.

[0040] Therefore, the elastic threads 4F1 and 4F2 are provided on the cover sheet 4 so that their longitudinal direction, which is the direction of stretch, coincides with the left-right direction of the diaper 1. The elastic threads 4R1 and 4R2 are provided on the cover sheet 4 so that their longitudinal direction, which is the direction of stretch, coincides with the left-right direction of the diaper 1. When the edges 4F4 and 4R4 (see FIG. 3) are joined together and the edges 4F5 and 4R5 are joined together, the elastic threads 4F1 and 4F2 and the elastic threads 4R1 and 4R2 form a substantially annular elastic member that runs along the waist opening 2T, thereby contracting the waist opening 2T in the waist direction. The elastic threads 4F1 and 4F2 and the elastic threads 4R1 and 4R2 exert a contractile force to fit the diaper 1 closely to the wearer and prevent a gap from forming between the diaper 1 and the wearer's abdominal circumference. The elastic threads 4F2 and 4R2 partially overlap the absorbent core 8 on the crotch region 1B side.

[0041] The elastic threads 4F1 and 4R1 are provided to extend laterally along the upper edges of the front body region 1F and the back body region 1R shown in FIG. 2. The elastic threads 4F2 and 4R2 are provided parallel to each other at a predetermined distance. When the diaper 1 is worn, the elastic threads 4F1 and 4R1 tightly tighten the wearer's abdominal circumference above the elastic threads 4F2 and 4R2. The elastic threads 4F1 and 4R1 fit the diaper 1 closely to the wearer, preventing it from shifting position and preventing leakage of excreted fluid from the abdomen or back. The elastic threads 4F2 and 4R2 alleviate the feeling of pressure on the wearer caused by the contractile force of the elastic threads 4F1 and 4R1.

[0042] Furthermore, rubber threads 4F3 and 4R3 are adhered to the cover sheet 4. The rubber threads 4F3 and 4R3 are elastic members provided in an area of ​​the cover sheet 4 closer to the crotch region 1B than the rubber threads 4F2 and 4R2. However, unlike the other rubber threads that are adhered continuously from the left end to the right end of the cover sheet 4, the rubber threads 4F3 and 4R3 are curved toward the crotch region 1B and overlap with part of the core wrap sheet 7 at the narrowed portion of the hourglass-shaped absorbent core 8c. This configuration allows the rubber threads 4F3 and 4R3 to function as leg gathers 3LL and 3LR.

[0043] The cover sheet 4 is folded back at the fold lines 4FF, 4RF and extends to the areas where the rubber threads 4F1, 4R1 are disposed, reinforcing the areas where the rubber threads 4F1, 4R1 are disposed with the folded back portions. The end sheets 11F, 11R are provided in the areas where the rubber threads 4F2, 4R2 are disposed and not extended by the cover sheet 4 folded back at the fold lines 4FF, 4RF, reinforcing the areas where the rubber threads 4F2, 4R2 are disposed.

[0044] In the present application, the term "overlapping of sheets" does not necessarily mean that the overlapping sheets are in full contact with each other, but rather includes a concept that includes a configuration in which only portions of the sheets overlap. For example, the end sheet 11F is overlapped such that a portion of one longitudinal end of the back sheet 6 touches a portion of the cover sheet 4. The diaper 1 is formed by stacking the back sheet 6 and top sheet 9 with the absorbent body 8 sandwiched therebetween, as well as the cover sheet 4, end sheets 11F and 11R, inner cover sheet 5, and side sheets 10L and 10R, and can therefore be said to have a laminate formed by stacking these multiple sheets.

[0045] The top sheet 9 of the diaper 1 has perforations along its edges. By tearing these perforations and moving the top sheet 9 surrounded by the torn perforations toward the skin side, the top sheet 9 and the absorbent body 8 (core wrap sheet 7 and absorbent core 8c) bonded to the top sheet 9 can be peeled off from the back sheet 6 as a unit.

[0046] The biodegradable nonwoven fabric used in the top sheet 9 can be produced by, for example, the nonwoven fabric production device described in JP 2021-70874 A. That is, as the raw material resin A top sheet 9 made of biodegradable resin fibers is formed by supplying polylactic acid resin or polybutylene succinate resin, which are examples of biodegradable resins, to a hopper of a nonwoven fabric production device (an example of the "production process" of the present disclosure).

[0047] Furthermore, in the medical and nursing care facility 40, many residents 90 wear diapers. Therefore, the facility regularly purchases a large amount of diapers from an external manufacturer.

[0048] The soil 50 is owned by a farmer. The soil 50 contains, for example, straw, rice husks, bark, and animal droppings such as cow droppings (examples of "predetermined organic matter derived from animals or plants" in the present disclosure), which have been piled up and then mixed with soil and allowed to rot. Note that this soil 50 does not contain, for example, sludge or fish organs. The top sheet 9 and absorbent core 8 that have been peeled off from the back sheet 6 of a worn diaper 1 will then be buried in this soil 50 (details will be described later).

[0049] Furthermore, gardening supply store 60 sells fertilizer 80 capable of promoting the growth of crops planted in soil to consumers 70. Consumer 70 may be, for example, a farmer or an individual who owns a garden at home where fertilizer 80 can be spread.

[0050] (Example of using the Soil Improvement System 100) Next, an example of how the above-described soil improvement system 100 can be used will be outlined. First, a manufacturer 30 purchases polylactic acid resin from a raw material manufacturer 85. Then, the manufacturer 30 produces a biodegradable top sheet 9 using the polylactic acid resin as a raw material. The manufacturer 30 also produces other components to complete the diaper 1. The manufactured diaper 1 is then sold to a medical or nursing care facility 40.

[0051] Diapers 1 are delivered periodically from a manufacturer 30 to a medical / nursing care facility 40. A resident wears the diaper 1 as shown in FIG. 2. After a predetermined period of time, the diaper 1 is removed and replaced with a new diaper 1. In this case, urine and feces excreted by the wearer adhere to the top sheet 9 of the used diaper 1. In other words, the wearer's excrement can adhere to the top sheet 9. The basis weight of the top sheet 9 is approximately 5 to 100 gsm. Therefore, the moisture contained in urine or watery feces (hereinafter referred to as excreted liquid) penetrates to the core wrap sheet 7.

[0052] Furthermore, the discharged liquid that has permeated the core wrap sheet 7 reaches the SAP contained in the absorbent core 8c. Since the SAP content here is about 5 to 70%, the discharged liquid that has reached it is held by the SAP.

[0053] Such used diapers 1 are collected by the manufacturer 30 (an example of the "collection process" of the present disclosure). The collected diapers 1 may be used as the soil conditioner 20 as is, or the top sheet 9 and absorbent body 8 may be separated from the back sheet 6 at the factory of the manufacturer 30 and used. The manufacturer 30 may collect used diapers 1, for example, when the manufacturer 30 delivers new diapers 1 to a medical or nursing care facility 40, or when a predetermined number of used diapers 1 have accumulated at the medical or nursing care facility 40.

[0054] FIG. 5 shows an example of the outline of the top sheet 9 and absorbent body 8 separated from the back sheet 6 of a worn diaper 1. As mentioned above, the top sheet 9 has perforations along its edges. Therefore, by tearing the perforations in the top sheet 9, the top sheet 9, absorbent body 8, side sheets 10L, 10R, and end sheets 11F, 11R can be separated from the back sheet 6 of the diaper 1. Furthermore, the side sheets 10L, 10R, and The end sheets 11F, 11R can be peeled away from the top sheet 9 and the absorbent body 8. In other words, the top sheet 9, the absorbent body 8, and each component of the diaper can be separated. In this way, as shown in FIG. 5, the top sheet 9 with feces attached and the absorbent body 8 in which excreted liquid is retained by SAP can be separated from the back sheet 6 of the diaper 1 (an example of the "separation step" of the present disclosure). The top sheet 9 and the absorbent body 8 separated from the back sheet 6 are then rolled up into a cylindrical shape with the top sheet 9 facing inward. The top sheet 9 and the absorbent body 8 separated from the back sheet 6 of the diaper 1 are then used as a soil conditioner 20 for sale. The step of separating the top sheet 9 and the absorbent body 8 from the back sheet 6 can be automated using a predetermined device.

[0055] The manufacturer 30 sells such soil conditioner 20 to, for example, farmers. The manufacturer 30 transports and spreads the soil conditioner 20 on the soil 50 of the farmer who purchased the soil conditioner 20. FIG. 6 is an example of a schematic diagram illustrating how the soil conditioner 20 is spread on the soil 50 and buried. The soil conditioner 20 is transported while folded into a cylindrical shape with the top sheet 9 facing inward. As shown in FIG. 6, the soil conditioner 20 is then spread on the soil 50 containing straw, rice husks, bark, and animal feces such as cow feces, and buried (an example of the "repurposing process" of the present disclosure). Therefore, biodegradation of the top sheet 9 is promoted by bacteria contained in the adhering feces or microorganisms contained in the soil 50. The soil conditioner 20 is automatically spread by a predetermined spraying device. The soil conditioner 20 may be sold not only to farmers but also to individuals who wish to improve the soil in their own yards.

[0056] The fiber diameter of the polylactic acid fibers contained in the top sheet 9 is finely divided, approximately 0.1 to 50 denier. This fine fiber diameter also promotes the biodegradation of the top sheet 9. Furthermore, if the absorbent core 8c contains pulp, the pulp is also decomposed by microorganisms. Furthermore, plant-derived organic matter such as straw, rice husks, and bark, as well as feces and animal droppings such as cow droppings that adhere to the top sheet 9, are also decomposed by microorganisms.

[0057] The soil conditioner 20 has a density in the soil 50 of 10 to 1000 g / m per land area. 2 The soil conditioner 20 is spread and buried so that the SAP content is about 5 to 70%. This improves the moisture retention effect of the soil 50. This also activates the activity of the microorganisms contained in the soil 50. This improves the function of the soil conditioner 20 as an improver for agricultural land in the soil 50. Furthermore, the activation of the microorganisms also promotes the biodegradation of the top sheet 9.

[0058] Furthermore, in the soil 50 into which the soil conditioner 20 has been buried, plant-derived organic matter such as straw, rice husks, and bark, as well as feces attached to the top sheet 9 and animal droppings such as cow dung buried in the soil 50, are decomposed by activated microorganisms into substances that are easily absorbed by plants. Therefore, the manufacturer 30 bags a portion of the soil 50 as fertilizer 80 for sale a predetermined period of time after the soil conditioner 20 has been buried. The manufacturer 30 then sells the bagged fertilizer 80 to, for example, a gardening supply store 60. The gardening supply store 60 that purchased the fertilizer 80 then sells the fertilizer 80 to consumers 70.

[0059] The soil improvement system 100 may be controlled by a computer equipped with a central processing unit, a main memory, an auxiliary memory, and a transceiver, which are owned by the manufacturer 30. Specifically, this control can be realized by loading a program for implementing the soil improvement system 100, which is stored in the auxiliary memory, into the main memory and executing it with the central processing unit. The computer controls the diaper 1 manufacturing equipment of the manufacturer 30 and manages the production of the diapers 1 by having the central processing unit execute the program loaded into the main memory. In addition to the computer that manages the soil management system 100, there may be a separate computer that manages the manufacturing process of the diapers 1, and the computer that manages the soil management system 100 may control the manufacturing process. It is also possible to configure the system so as to control a computer that manages the above.

[0060] The computer managing the soil management system 100, for example, measures the amount of used diapers at the medical / nursing care facility 40 using a sensor, inputs the data into a transceiver via communication means, and issues instructions to collect and deliver new diapers at the appropriate time. More specifically, the computer communicates with a sensor measuring the amount of diapers in the used diaper collection box at the medical / nursing care facility 40 at a regular interval using communication means such as a wired or wireless LAN, a mobile phone line, or the Internet or a private network. A program read from the auxiliary storage device and loaded into the main storage device determines the amount of diapers measured by the sensor and issues a collection instruction when the amount of used diapers 1 exceeds a certain amount. Alternatively, the computer may measure the amount of unused diapers 1 in stock at the medical / nursing care facility 40 using a sensor, and when the amount of unused diapers 1 falls below a certain amount, issue an instruction to deliver new diapers, and collect the diapers at the time of delivery. It is also possible to predict the collection and delivery times using a learning model that has been trained in advance based on sensor measurement information and the size of the medical / nursing facility 40, and to carry out delivery and collection according to the prediction.

[0061] Alternatively, an image sensor or soil sensor may be installed in the soil 50, and the computer managing the soil management system 100 may manage this via communication means. The computer uses information obtained from the sensor to determine whether the soil conditioner 20 has sufficiently decomposed into substances easily absorbed by plants. Specifically, the degree of decomposition is determined based on information such as whether the top sheet 9 and absorbent core 8c are retaining their shape, obtained by analyzing images obtained from the image sensor using known methods, in addition to numerical information such as nutrients provided by the soil sensor. Because decomposition is influenced by environmental factors such as the temperature and precipitation around the soil 50, a learning model that has previously learned this information in addition to the sensor information described above may be installed in the computer to predict when the soil 50 is suitable for farming. By providing the farmer with information obtained using these methods, the farmer can determine whether the soil 50 is in a suitable condition for farming. Furthermore, when the manufacturer 30 sells the soil 50 as fertilizer 80 after a predetermined period of time has passed since the soil conditioner 20 was buried, the computer determines or predicts using the above-described method whether the soil conditioner 20 has sufficiently decomposed to be packaged as fertilizer 80, and outputs instructions. In this way, by using the computer that manages the soil management system 100, the manufacturer 30 can repurpose the diapers 1 for use by farmers.

[0062] [Actions and Effects] The top sheet 9 of a used diaper 1 used in a medical or nursing care facility 40 has wearer feces attached to it. Therefore, the manufacturer 30 can make a profit by collecting the top sheet 9 and absorbent body 8 and selling them as a soil conditioner 20. This is because the soil conditioner 20 can be composted by burying it in the soil 50. Furthermore, the absorbent body 8 contained in the soil conditioner 20 retains the wearer's urine. Therefore, the soil 50 in which the soil conditioner 20 is buried improves the moisturizing effect of the soil 50. This improved moisturizing effect improves the soil improvement function. For these reasons, too, the manufacturer 30 can make a profit by selling the soil conditioner 20. In other words, by collecting used diapers 1 and selling them to farmers as soil conditioner 20, the manufacturer 30 can recover at least a portion of the raw material cost of the biodegradable top sheet 9 from the farmers. Therefore, the soil improvement system 100 described above allows the manufacturer 30 to reduce the price of diapers 1 used daily in medical or nursing care facilities 40 and the like.

[0063] Furthermore, a portion of the soil 50 in which the soil conditioner 20 has been buried for a predetermined period of time is sold as fertilizer 80 to consumers 70 via gardening supply stores 60. Thus, the manufacturer 30 can recover at least a portion of the raw material cost of the biodegradable top sheet 9 from the gardening supply stores 60. This system also allows the manufacturer 30 to keep the price of the diaper 1 low.

[0064] Furthermore, according to the soil improvement system 100 described above, in the soil 50 in which the soil improvement agent 20 has been buried, microorganisms contained in feces adhering to the top sheet 9 promote biodegradation of the top sheet 9 itself. Furthermore, urine retained in the absorbent 8 improves the moisturizing effect of the soil 50, which in turn stimulates microbial activity and promotes biodegradation of the top sheet 9. Therefore, the biodegradation of the top sheet 9 can be easily shortened without establishing a compost environment. Therefore, the time required to sell a portion of the soil 50 as fertilizer 80 can be shortened. Therefore, the recovery of the raw material costs of the biodegradable top sheet 9 can be shortened. Therefore, even if the manufacturer 30 starts selling the diaper 1 at a low price, the possibility of this putting a strain on the manufacturer's profits is reduced.

[0065] Furthermore, according to the soil improvement system 100 described above, the soil conditioner 20 is folded into a cylindrical shape so that the top sheet 9 with the feces attached is on the inside. Therefore, the feces can be transported wrapped in the top sheet 9 and absorbent 8 and buried in the soil 50. This prevents the feces from adhering to the outside during transport, making it hygienic. Furthermore, a decrease in the amount of feces contained in the soil conditioner 20 due to the feces adhering to the outside during transport is suppressed. Therefore, a decrease in its function as a soil conditioner is suppressed.

[0066] [Variations] FIG. 7 illustrates an overview of a soil improvement system 100A according to a modified example. The soil improvement system 100A according to the modified example is similar to the soil improvement system 100 according to the embodiment. However, in the soil improvement system 100A according to the modified example, a manufacturer 30A sells diapers 1 to consumers 70A via a daily necessities retailer 65. The manufacturer 30A then collects used diapers 1 worn by the consumers 70A. The used diapers 1 may be placed by the consumers 70A in a collection box permanently installed at a convenience store, for example, and the used diapers 1 may be periodically collected from the collection box by a collection vehicle. Then, at the factory of the manufacturer 30A, the top sheet 9 and absorbent body 8, to which urine, feces, etc., have been adhering, are separated from the back sheet 6 and used as a soil conditioner 20, as in the soil improvement system 100 according to the embodiment. This soil improvement system 100A also achieves the same effects as the embodiment.

[0067] The soil improvement system 100A may also be controlled by a computer equipped with a central processing unit, a main memory device, an auxiliary memory device, and a transceiver device, all of which are owned by the manufacturer 30A. Specifically, this control is achieved by loading a program for implementing the soil improvement system 100A, stored in the auxiliary memory device, into the main memory device and executing it with the central processing unit. In this modification, a sensor is provided in the collection box, and information on the accumulation of diapers 1 is transmitted to the transceiver device of the computer via communication means. When a sufficient number of used diapers 1 have accumulated in the collection box, the computer issues a collection instruction for the diapers 1 from the collection box. The computer may also be equipped with a learning model that learns from the number of diaper 1 consumers in the area estimated from sales data and the past accumulation trend of diapers 1 in collection boxes. In addition to or instead of the sensor information, the computer may issue a collection instruction at appropriate times based on the prediction results of the learning model. Other computer operations are similar to those of the above-described embodiment.

[0068] [Other variations] The density of the soil conditioner 20 in the soil 50 is not limited to the examples described above. The soil 50 does not have to contain straw, rice husks, bark, or animal dung such as cow dung. The absorbent core 8c contained in the soil conditioner 20 does not have to be covered with the core wrap sheet 7. The basis weight of the top sheet 9 is not limited to the examples described above. The SAP content is not limited to the examples described above.

[0069] The features described in the various embodiments and modifications described above can be combined to the greatest extent possible. [Explanation of symbols]

[0070] 1: Diapers 1B: Inseam area 1F: Front body area 1R: Back area 2L: Left lower limb opening 2R: Right lower limb opening 2T: Body opening 3BL, 3BR: 3D gathers 3LL: Leg gathers 3R: Waist Gather 4: Cover sheet 4F1, 4F2, 4F3: Elastic thread 4F4, 4F5: Edge 4FF, 4RF: Folded lines 4R1, 4R2, 4R3: Elastic thread 4R4, 4R5: Edge 5: Inner cover sheet 6: Back seat 7: Core wrap sheet 8: Absorber 8a: Upper layer absorbent mat 8b: Lower absorbent mat 8c: Absorbent core 9: Topsheet 10L, 10R: Side seats 10L1, 10R1: Elastic thread 10L2, 10R2: Folding lines 11F, 11R: End seat 12: Tummy Gather 20: Soil conditioner 30, 30A: Manufacturer 40: Medical and nursing care facilities 50: Soil 60: Gardening supplies store 65: General merchandise store 70, 70A: Consumer 80: Fertilizer 85: Raw material manufacturer 90: Tenant 100, 100A: Soil improvement system

Claims

1. A soil improvement method using an absorbent article capable of absorbing liquid excreted by a wearer, comprising: A production process in which a business produces an absorbent article including a water-absorbent polymer and a biodegradable nonwoven fabric, the absorbent article having the water-absorbent polymer and the biodegradable nonwoven fabric disposed on the skin-facing side of a non-permeable back sheet; a collecting step of collecting the absorbent article after use by the wearer; a separation step of separating the water-absorbent polymer and the biodegradable nonwoven fabric from the collected used absorbent article by peeling them off from the backsheet; and a repurposing step in which the business operator repurposes the water-absorbent polymer and the biodegradable nonwoven fabric separated from the used absorbent article for use by farmers as soil conditioners for agricultural land. Soil improvement methods.

2. In the collection step, the absorbent articles manufactured by the business operator and used in medical / nursing care facilities used by the wearer are collected. The soil improvement method according to claim 1.

3. In the conversion step, the absorbent article is sold to the farmer as a soil conditioner for agricultural soil. The soil improvement method according to claim 1 or 2.

4. In the conversion step, at least a portion of the soil to which the soil improver has been sprayed is further sold to the farmer. The soil improvement method according to claim 3.

5. In the repurposing step, the absorbent article is absorbed in the soil at a rate of 10 to 1000 g / m per area. ２ The dispersion is made to be in the range of The soil improvement method according to claim 3 or 4.

6. The soil contains predetermined organic matter derived from animals or plants. The soil improving method according to any one of claims 3 to 5.

7. A soil improvement system using an absorbent article capable of absorbing liquid excreted by a wearer, A production means by which a business operator produces an absorbent article including a water-absorbent polymer and a biodegradable nonwoven fabric, the absorbent article having the water-absorbent polymer and the biodegradable nonwoven fabric disposed on the skin-facing side of a water-impermeable back sheet; a collecting means for collecting the absorbent article after it has been used by the wearer; a separating means for separating the water-absorbent polymer and the biodegradable nonwoven fabric from the collected used absorbent article by peeling the water-absorbent polymer and the biodegradable nonwoven fabric from the backsheet; and a repurposing means for the business operator to repurpose the water-absorbent polymer and the biodegradable nonwoven fabric separated from the used absorbent article and provide them to farmers as soil conditioners for agricultural land. Soil improvement system.

Images