Absorber, absorbent article, and method for producing absorber

Abstract

Provided are an absorber and an absorbent article that exhibit improved absorption performance, and a method for producing said absorber. The absorber comprises a sheet that includes cotton fibers having a network structure and that has a bulk density of 0.001-6.0 g / cm3. The method for producing an absorber having a densified sheet comprises a forming step for using a roll press to compress a sheet that includes cotton fibers and has a bulk density of 0.001-0.50 g / cm3, and forming said sheet into a densified sheet that has a bulk density of 0.005-6.0 g / cm3.

Description

Absorbent material, absorbent article, and method for manufacturing an absorbent material

[0001] This invention relates to absorbents, absorbent articles, and methods for manufacturing absorbents.

[0002] Conventionally, as an absorbent material used in disposable wearable items, there is a known type in which an absorbent polymer is arranged on pulp fibers, as disclosed in Patent Document 1 (International Publication No. 2021 / 049275). In the absorbent material manufacturing apparatus of Patent Document 1 (International Publication No. 2021 / 049275), a surface with suction holes is prepared, and pulp fibers containing the absorbent polymer, on which the absorbent polymer has been scattered, are drawn in along with air through the suction holes, accumulating on the surface and forming a layer of pulp fibers mixed with the absorbent polymer.

[0003] International Publication No. 2021 / 049275

[0004] However, since pulp fibers do not have very high absorbency, there is room for improvement in absorbents that use pulp fibers as a component, in terms of absorption capacity.

[0005] The absorbent material of the present invention contains cotton fibers having a mesh-like structure and has a bulk density of 0.001 to 6.0 g / cm³. ３ It is equipped with seats.

[0006] The absorbent article of the present invention contains cotton fibers having a mesh-like structure and has a bulk density of 0.001 to 6.0 g / cm³. ３ It comprises an absorbent body with a sheet, a top sheet, and a back sheet. The absorbent body is positioned between the top sheet and the back sheet.

[0007] The present invention relates to a method for manufacturing an absorbent material having a compacted sheet. The manufacturing method involves using a roll press to produce a compacted sheet containing cotton fibers with a bulk density of 0.001 to 0.50 g / cm³. ３ The sheet is compressed, and the bulk density is 0.005 to 6.0 g / cm³. ３ The process includes a forming step of forming a compacted sheet.

[0008] The absorbent material and absorbent article of the present invention comprises a sheet containing cotton fibers. Therefore, the absorbent performance of the absorbent material and absorbent article can be improved.

[0009] According to the method for manufacturing absorbents of the present invention, it is possible to manufacture absorbents with improved absorption performance.

[0010] This is a schematic front view of a disposable diaper, an example of an absorbent article. This is a diagram showing the disposable diaper from Figure 1 with the side seal unfolded. This is an example of a cross-sectional view of the absorbent body along line A-A' from Figure 2. This is another example of a cross-sectional view of the absorbent body along line A-A' from Figure 2. This is a schematic flowchart showing the manufacturing process of a cotton fiber sheet using a pre-bleaching method. This is a schematic flowchart showing the manufacturing process of a cotton fiber sheet using a post-bleaching method. This is a schematic diagram of the absorbent. This is a cross-sectional view of the absorbent from line B-B' from Figure 5. This is a diagram to explain the joint of the absorbent. This is a schematic flowchart showing the manufacturing process of the absorbent. This is a schematic flowchart showing the manufacturing process of the absorbent of Modified Example I. This is a schematic flowchart showing the manufacturing process of the absorbent of Modified Example J. This is a schematic flowchart showing the manufacturing process of the absorbent of Modified Example K. This is a diagram to explain the manufacturing process of a compacted cotton fiber sheet. This is a schematic flowchart showing the manufacturing process of a cotton fiber sheet related to Modified Example L.

[0011] The following describes embodiments of the absorbent material, absorbent article, and method for manufacturing the absorbent material according to the present invention, with reference to the drawings.

[0012] The embodiments described below are merely examples of the present invention and do not limit the scope of the invention. Those skilled in the art will understand that various modifications can be made to the following embodiments without departing from the spirit and scope of the invention as described in the claims.

[0013] (1) Absorbent Articles An example of absorbent articles relating to one embodiment of the present invention will be described with reference to Figures 1 and 2.

[0014] Figure 1 is a schematic front view of a disposable diaper 1 (hereinafter simply referred to as diaper 1), which is an example of an absorbent article. Figure 2 is a diagram of diaper 1 with the side seal portion 5, which will be described later, unfolded.

[0015] In this embodiment, absorbent articles will be described using disposable diapers as an example. However, absorbent articles are not limited to disposable diapers, as long as they are wearable articles having a liquid-absorbing component, such as the absorbent body 10 described later.

[0016] This section provides details about diaper 1. Note that in the following description, terms such as "front," "back," "left," and "right" may be used. Unless otherwise specified, these terms refer to the direction diaper 1 is facing when worn by the wearer, as viewed from their perspective.

[0017] As shown in Figure 1, diaper 1 has a symmetrical structure. As shown in Figure 2, diaper 1 mainly consists of an absorbent body 2, a front torso 3, and a rear torso 4.

[0018] As shown in Figure 2, the absorbent body 2 extends between the front torso portion 3 and the rear torso portion 4 and is a component that covers the wearer's crotch. The front torso portion 3 is a component that covers the front of the wearer's torso, and the rear torso portion 4 is a component that covers the rear of the wearer's torso.

[0019] The absorbent body 2, front torso 3, and rear torso 4, which make up diaper 1, will be described in detail below.

[0020] In the following explanation, the direction in which the garment extends around the wearer's waist when worn (the left-right direction in Figures 1 and 2) will be referred to as the waist direction X1, and the direction perpendicular to the waist direction X1, which is the longitudinal direction of the absorbent body 2, will be referred to as the vertical direction X2.

[0021] Here, diaper 1 refers to a pull-up type diaper. However, the type of diaper is not limited to the pull-up type; it may also be a tape-type diaper in which the front and back sections are separate (not joined by the side seal section 5) and the front and back sections are fastened together with tape when worn.

[0022] In this embodiment, the pants-type diaper 1, in its finished state (as shown in Figure 1), has the absorbent body 2 folded in half in the middle in the vertical direction X2, and the left and right ends of the front torso 3 in the waist direction X1 overlap each other with the left and right ends of the rear torso 4 in the waist direction X1, as shown in Figure 1. The ends of the front torso 3 in the waist direction X1 and the ends of the rear torso 4 in the waist direction X1 are joined at the side seal portion 5 (see Figure 1).

[0023] Figures 3A and 3B are cross-sectional views of the absorbent body 2 in Figure 2 along the line A-A'. As shown in Figure 3A, the absorbent body 2 includes a top sheet TS, a back sheet BS, and an absorbent 10 positioned between the top sheet TS and the back sheet BS. Note that the structure of the absorbent body 2 shown here is merely illustrative, and the absorbent body 2 may include components other than the top sheet TS, back sheet BS, and absorbent 10. Also, as shown in Figure 3B, the absorbent body 2 may consist of an absorbent 10 that also serves as the top sheet TS and a back sheet BS. The top sheet TS is a sheet positioned on the skin-contacting side (the inner side facing the wearer's skin) when worn, and is a liquid-permeable sheet. The back sheet BS is a sheet positioned on the opposite side of the top sheet TS (the outer side not facing the wearer's skin), and is a liquid-impermeable sheet. The absorbent 10 is a component that absorbs bodily fluids such as urine (hereinafter referred to as excrement) of the wearer, and includes a layer containing cotton fibers.

[0024] As shown in Figure 2, the absorbent body 2 is a substantially rectangular member. The absorbent body 2 extends between the front body portion 3 and the rear body portion 4, with the vertical direction X2 as its longitudinal direction. The absorbent body 2 is joined to the front body portion 3 at the center of the front body portion 3 in the circumference direction X1, and is joined to the rear body portion 4 at the center of the rear body portion 4 in the circumference direction X1.

[0025] The front torso 3 and rear torso 4 each have an inner sheet 6 that faces the wearer's skin and an outer sheet 7 that does not face the wearer's skin (which is positioned on the outside when the wearer puts it on). The inner sheet 6 and the outer sheet 7 are laminated together. The outer sheet 7 not only constitutes the front torso 3 and rear torso 4, but also extends continuously to connect the front torso 3 and rear torso 4. The outer sheet 7 positioned between the front torso 3 and rear torso 4 in the vertical direction X2 forms the leg hole portion. Furthermore, as shown in Figure 2, the absorbent body 2 is positioned on the outer sheet 7 positioned between the front torso 3 and rear torso 4 in the vertical direction X2.

[0026] Elastic members F are placed in the front torso 3 and rear torso 4 to fit the diaper 1 to the wearer. In the front torso 3 and rear torso 4, the elastic members F are placed between the inner sheet 6 and the outer sheet 7, and in this state, the inner sheet 6 and the outer sheet 7 are joined together. Furthermore, the elastic members F are joined to at least one of the inner sheet 6 and the outer sheet 7. The elastic members F can be made of materials such as multiple strands of elastic thread, flat elastic, or thermoplastic resin. Note that the structure of the front torso 3 and rear torso 4 shown here is merely illustrative, and the front torso 3 and rear torso 4 may include members other than the inner sheet 6, outer sheet 7, and elastic members F.

[0027] As shown in Figure 2, the absorbent body 10 has substantially the same shape as the absorbent body 2 and is a substantially rectangular member. The absorbent body 10 is sandwiched between the top sheet TS and the back sheet BS. The absorbent body 10 is mainly composed of cotton fibers formed into a sheet (hereinafter referred to as cotton fiber sheet 11) and an absorbent polymer 8.

[0028] (2) The cotton fiber sheet 11, which is the main component material of the cotton fiber sheet absorbent 10, will be described. Cotton fiber refers to fibers obtained from cotton plants. Cotton fibers have cavities inside the fibers, so they have higher absorption and water retention capacity compared to pulp fibers. The cotton fiber sheet 11 is an aggregate of cotton fibers, a piled fiber body made of cotton fibers. A method for manufacturing the cotton fiber sheet 11 using a pre-bleaching method will be described with reference to Figure 4A.

[0029] In manufacturing, first, the intertwined cotton is unwound and impurities are removed (Steps S1, S2). Impurities include, for example, seeds, leaves, stems, dust, etc.

[0030] Next, the unwound cotton fibers are scoured and bleached (Step S3). In this process, the oil on the surface of the cotton fibers is removed, and the absorption performance of the cotton fibers can be enhanced.

[0031] Next, the cotton fibers are combed to align the fiber directions, then deposited, processed into a sheet shape, and wound into a roll shape to form a raw cotton roll 20 (Step S4). At this time, the cotton fiber sheet 11 is processed so that its bulk density is 0.001 - 6.0 cm ３ Considering that it will be densified in the subsequent process (if the bulk density is too high, further densification becomes difficult, and if the bulk density is too large, the penetration performance will decrease), the cotton fiber sheet 11 is processed so that its bulk density is 0.001 - 4.0 cm ３ ). More preferably, the cotton fiber sheet 11 is processed so that its bulk density is 0.001 - 0.50 g / cm ３ And even more preferably, the cotton fiber sheet 11 is processed so that its bulk density is 0.004 - 0.50 g / cm ３ Since cotton fibers have a long fiber length, in the cotton fibers processed into a sheet shape, the cotton fibers are intertwined with each other to form a mesh-like structure. As a result, a laminate of cotton fibers having a mesh-like structure is formed. Note that the mesh-like structure means a structure in which the intertwined cotton fibers spread three-dimensionally in a mesh-like manner.

[0032] Then, by applying pressure to the laminate of the cotton fibers processed into a sheet shape (the sheet unwound from the raw cotton roll 20), a sheet with a predetermined bulk density is formed (Step S5). Specifically, the sheet is densified by roll pressing. The predetermined bulk density is 0.005 - 6.0 g / cm ３This is the case. When pressure is applied to the cotton fiber assembly, the distance between the cotton fibers decreases, and the cotton fibers become more intertwined. As a result, the voids in the network structure formed by the cotton fibers become smaller, and the bulk density increases compared to before consolidation. Note that the bulk density can be determined based on the conveying strength (the greater the bulk density, the stronger), the diffusion performance (the greater the bulk density, the higher), and the penetration performance (the greater the bulk density, the lower).

[0033] Thus, by using a roll press, unlike the conventional manufacturing method, a cotton fiber sheet 11 (hereinafter referred to as a consolidated cotton fiber sheet 12) that is simply consolidated can be manufactured without performing a process of loosening the raw cotton roll 20 again after step S4.

[0034] Note that the cotton fiber sheet 11 may be manufactured using the post-exposure method shown in FIG. 4B instead of the pre-exposure method shown in FIG. 4A described above. The flow of the process shown in FIG. 4B is the reverse of the order of steps S3 and S4 in FIG. 4A. Since the contents of the processes in steps S11, S12, S13, and S15 in FIG. 4B are the same as the contents of the processes in steps S1, S2, S4, and S5 in FIG. 4A, the description thereof is omitted. In step S14, the raw cotton roll 20 is scoured and bleached. In this process, the oil on the surface of the cotton fibers is removed, and the absorption performance of the cotton fibers can be improved.

[0035] Generally, the pre-bleaching method is considered to have good manufacturing efficiency. However, because the cotton fibers are scouring and bleaching before the raw cotton roll 20 is formed, and the oil on the surface of the cotton fibers is removed, static electricity is generated when the raw cotton roll 20 is formed. As a result, the cotton fibers do not intertwine well and become fuzzy, so it is necessary to smooth the surface of the cotton fiber sheet 11 with a water jet. As a result, the pre-bleaching method puts a load on the cotton fibers, which may cause pilling or hardening. In contrast, in the post-bleaching method, the raw cotton roll 20 is formed before the oil on the surface of the cotton fibers is removed, and the raw cotton roll 20 is scouring and bleaching in that state. Because there is less load on the cotton fibers, the cotton fibers intertwine firmly, fuzzing is suppressed, and the original absorbency and bulkiness of cotton are maintained. As a result, as will be described later, it is advantageous for other fibers different from cotton fibers and absorbent polymers 8 to be mixed and uniformly held inside the mesh-like structure of the cotton fibers.

[0036] The order and content of each process in the flowcharts of Figures 4A and 4B described above can be modified as appropriate without departing from the spirit of the present invention.

[0037] (3) Absorbent The absorbent body 10 is mainly composed of a cotton fiber sheet 11 and an absorbent polymer 8, a polymer compound called SAP that has high absorbency. In the absorbent body 10 of this embodiment, the cotton fiber sheet 11 is preferably a densified cotton fiber sheet 12. The densified cotton fiber sheet 12 is an example of a densified sheet. As described above, the densified cotton fiber sheet 12 has a bulk density of 0.005 to 6.0 g / cm³. ３ This is the sheet.

[0038] The absorbent body 10 is preferably formed by laminating a plurality of densified cotton fiber sheets 12. The structure of the absorbent body 10 including two densified cotton fiber sheets 12 will be described below. Note that the number of densified cotton fiber sheets 12 included in the absorbent body 10 is not limited to two, and may include three or more densified cotton fiber sheets 12. Figure 5 is a schematic diagram of the absorbent body 10 when viewed along the thickness direction of the densified cotton fiber sheets 12. Figure 6 is a cross-sectional view of the absorbent body 10 in Figure 5 taken along the line B-B'.

[0039] The absorbent body 10 is composed of two laminated, compacted cotton fiber sheets 12 cut to predetermined dimensions. The space SP between the two compacted cotton fiber sheets 12 includes a central region (an example of a first region) A1 located in the center of the compacted cotton fiber sheets 12, and a peripheral region (an example of a second region) A2 located around the central region A1.

[0040] Absorbent polymer 8 is placed in space SP. More absorbent polymer 8 is placed in the central region A1 of space SP than in the peripheral region A2. In other words, the amount of absorbent polymer 8 per unit area placed in the central region A1 is greater than the amount of absorbent polymer 8 per unit area placed in the peripheral region A2. As shown in Figure 2, the absorbent body 10 is positioned to cover the wearer's groin. By increasing the amount of absorbent polymer 8 in the central region A1, the absorption performance of excrement can be improved. As a result, it becomes easier to ensure that the absorbent body 10 absorbs all excrement without leakage.

[0041] Furthermore, the absorbent body 10 may also be configured such that the absorbent polymer 8 is placed in the central region A1 of the space SP, but not in the peripheral region A2.

[0042] The densified cotton fiber sheet 12 has a first densified portion 13 and a second densified portion 14. The first densified portion 13 is formed in a fourth region located in the center of the densified cotton fiber sheet 12 when viewed along the thickness direction of the densified cotton fiber sheet 12. The second densified portion 14 is formed in a third region located at the periphery of the densified cotton fiber sheet 12 when viewed along the thickness direction of the densified cotton fiber sheet 12.

[0043] In this embodiment, when viewed along the thickness direction of the absorber 10, the position and shape of the first compaction portion 13 and the central region A1 are substantially the same, and the position and shape of the second compaction portion 14 and the peripheral region A2 are substantially the same. However, it is not limited to this, and for example, the area of ​​the first compaction portion 13 may be larger than or smaller than the area of ​​the central region A1. Also, for example, the area of ​​the second compaction portion 14 may be larger than or smaller than the area of ​​the peripheral region A2. Furthermore, the area of ​​the first compaction portion 13 and the central region A1 do not have to completely overlap, and the area of ​​the second compaction portion 14 and the peripheral region A2 do not have to completely overlap.

[0044] Two densified cotton fiber sheets 12 are joined by applying additional pressure to the second densified portion 14 (third region) with an absorbent polymer 8 sandwiched between them. Alternatively, the two densified cotton fiber sheets 12 are joined by applying additional pressure to the first densified portion 13 (fourth region) with a weaker pressure than that applied to the second densified portion 14. The densified cotton fiber sheets 12 may be joined using heat or adhesive.

[0045] As a result, the bulk density of the second compacted section 14 after pressurization is greater than that of the first compacted section 13 after pressurization. In other words, the joint strength of the second compacted section 14 after pressurization is greater than that of the first compacted section 13.

[0046] Preferably, when viewed along the thickness direction of the absorbent body 10, the position and shape of the first compaction portion 13 and the central region A1 are substantially the same as described above. As mentioned above, the central region A1 contains more absorbent polymer 8 than the peripheral region A2. The absorbent polymer 8 expands when it absorbs water. If the bulk density of the first compaction portion 13, where a large amount of absorbent polymer 8 is located, is high, the voids in the mesh-like structure formed by the cotton fibers become smaller, and it may become difficult to secure space for the expansion of the absorbent polymer 8. In other words, if the bulk density of the first compaction portion 13 is high, the absorption performance of the absorbent body 10 may decrease.

[0047] In contrast, in this embodiment, the bulk density of the second compaction section 14, which is laminated in the peripheral region A2 and has a small amount of absorbent polymer 8, is increased, while the bulk density of the first compaction section 13, which is laminated in the central region A1 and has a large amount of absorbent polymer 8, is decreased. This ensures that there is space for the absorbent polymer 8 to expand in the central region of the absorbent body 10 where a large amount of excrement adheres, thereby suppressing a decrease in the excrement absorption performance. Furthermore, in the peripheral region of the absorbent body 10, the strength of the bond between the compaction cotton fiber sheets 12 can be improved by increasing the bulk density (by strongly compressing the compaction cotton fiber sheets 12 together).

[0048] Specifically, as shown in the example in Figure 7, each of the first compaction section 13 and the second compaction section 14 may have a plurality of joints 15. The first compaction section 13 and the second compaction section 14 are joined by pressurization at the joints 15. In the second compaction section 14, a large number of linear joints 15 may be provided so as to reduce the area that is not pressurized. In the first compaction section 13, a grid-like joint 15 in which multiple straight lines intersect each other may be provided so as to form an area that is not pressurized. Note that the shape of the joints 15 is not limited to these.

[0049] The method for manufacturing the absorbent 10 will be explained with reference to Figure 8A.

[0050] First, the densified cotton fiber sheet 12 is cut to a predetermined size (step S21). Hereinafter, the two cut densified cotton fiber sheets 12 will be referred to as the first densified cotton fiber sheet 12a and the second densified cotton fiber sheet 12b. The first densified cotton fiber sheet 12a and the second densified cotton fiber sheet 12b are the same size.

[0051] Next, the absorbent polymer 8 is placed on the first compacted cotton fiber sheet 12a (step S22). At this time, for example, more absorbent polymer 8 is placed in the central region A1 than in the peripheral region A2.

[0052] Next, the second densified cotton fiber sheet 12b is laminated on top of the absorbent polymer 8 (so that the absorbent polymer 8 is positioned between the first densified cotton fiber sheet 12a and the second densified cotton fiber sheet 12b) (step S23).

[0053] In step S24, the second compaction portion 14, which is the peripheral area of ​​the first compaction cotton fiber sheet 12a and the second compaction cotton fiber sheet 12b, is pressurized, thereby joining and integrating the first compaction cotton fiber sheet 12a and the second compaction cotton fiber sheet 12b (additional compaction).

[0054] Furthermore, in step S24, the first densification section 13, which is the central area of ​​the first densified cotton fiber sheet 12a and the second densified cotton fiber sheet 12b, is pressurized, thereby joining the first densified cotton fiber sheet 12a and the second densified cotton fiber sheet 12b together (additional densification occurs).

[0055] The joining of the first compaction section 13 and the joining of the second compaction section 14 may be performed simultaneously.

[0056] The order and content of each process in the flowchart of Figure 8A described above can be modified as appropriate without departing from the spirit of the present invention.

[0057] (4) Absorbent body The absorbent body 2 includes, as described above, a top sheet TS, a back sheet BS, and an absorbent 10 positioned between the top sheet TS and the back sheet BS (see Figure 3A). In this embodiment, a compacted cotton fiber sheet 12 is also used for the top sheet TS.

[0058] Specifically, the densified cotton fiber sheet 12 produced in step S5 of Figure 4A is cut to a predetermined size to create the top sheet TS. The top sheet TS is the sheet that is placed on the side that comes into contact with the skin when worn. The absorbent body 10 is placed between the top sheet TS and the back sheet BS and joined together to form the absorbent body 2.

[0059] (5) Features (5-1) The absorbent material 10 of this embodiment contains cotton fibers having a mesh-like structure and has a bulk density of 0.001 to 6.0 g / cm³ ３ It is equipped with seats.

[0060] Cotton fibers have internal cavities, resulting in higher absorbency and water retention compared to pulp fibers. This structure improves the absorbency of the absorbent material 10. Furthermore, this absorbent material 10 can reduce skin irritation.

[0061] (5-2) The absorbent material 10 of this embodiment, which contains cotton fibers, has a bulk density of 0.005 to 6.00 g / cm³. ３ This is a compacted cotton fiber sheet 12. By using the compacted cotton fiber sheet 12, a highly absorbent absorbent body 10 can be realized in a compact form. In addition, the diffusion capacity of the sheet can be increased.

[0062] (5-3) The absorbent body 10 of this embodiment is made up of multiple densified cotton fiber sheets 12 laminated together. By increasing the amount of cotton fiber, the absorbent performance of the absorbent body 10 can be further improved.

[0063] (5-4) The absorbent body 10 of this embodiment further comprises an absorbent polymer 8 disposed in at least one of the spaces SP between two adjacent compacted cotton fiber sheets 12. This configuration further improves the absorption performance of the absorbent body 10.

[0064] (5-5) In this embodiment, when viewed along the lamination direction of the compacted cotton fiber sheet 12, the absorbent body 10 includes a central region A1 and a peripheral region A2 arranged around the central region A1. The central region A1 is the region located in the central part of the compacted cotton fiber sheet 12. The amount of absorbent polymer 8 per unit area in the central region A1 is greater than the amount of absorbent polymer 8 per unit area in the peripheral region A2.

[0065] By increasing the amount of absorbent polymer 8 placed in the central region A1 where a large amount of excrement adheres, the absorption performance of the absorbent body 10 can be further improved.

[0066] (5-6) The compacted cotton fiber sheet 12 of the absorbent body 10 of this embodiment has a first compacted portion 13 and a second compacted portion 14. The second compacted portion 14 has a higher bulk density than the first compacted portion 13.

[0067] The absorbent material 10 expands when it absorbs water. Also, the amount of excrement that adheres to the absorbent material 10 varies depending on its position. In other words, the degree of expansion of the absorbent material 10 differs depending on its position. When the bulk density is high, the voids in the mesh-like structure formed by the cotton fibers become smaller, which may reduce the absorption performance. However, the strength of the bond improves because the distance between the cotton fibers becomes closer.

[0068] By making the bulk density different between the first compacted portion 13 and the second compacted portion 14 of the compacted cotton fiber sheet 12, it is possible to improve the bonding strength of the compacted cotton fiber sheet 12 while maintaining the absorption performance of the absorbent material 10.

[0069] (5-7) In this embodiment, the absorbent body 10 has a second compaction portion 14 formed in a third region located at the periphery of the compaction cotton fiber sheet 12 when viewed along the thickness direction of the compaction cotton fiber sheet 12. The first compaction portion 13 is formed in a fourth region located in the center of the compaction cotton fiber sheet 12 when viewed along the thickness direction of the compaction cotton fiber sheet 12.

[0070] In this absorbent material 10, the bulk density is higher in the peripheral region of the compacted cotton fiber sheet 12 than in the central region. By reducing the bulk density in the central region where a large amount of excrement adheres, it is possible to secure space for the absorbent material 10 and absorbent polymer 8 to expand in the central region. Furthermore, by increasing the bulk density in the peripheral region, the strength of the bond in the peripheral region can be improved. As a result, even when the absorbent material 10 and absorbent polymer 8 absorb water and expand, peeling and displacement of the compacted cotton fiber sheet 12 can be reduced.

[0071] (5-8) The diaper 1 of this embodiment comprises an absorbent body 10, a top sheet TS, and a back sheet BS having the above-described features. The absorbent body 10 is positioned between the top sheet TS and the back sheet BS.

[0072] This diaper 1 features a sheet containing cotton fibers, which improves its absorbency. Furthermore, this diaper 1 can reduce skin irritation.

[0073] (5-9) The top sheet TS of diaper 1 in this embodiment has a bulk density of 0.005 to 6.0 g / cm³ ３ It is composed of a densified cotton fiber sheet 12.

[0074] This diaper 1 has a top sheet TS that comes into contact with the wearer's skin, and since it is made of a sheet containing cotton fibers, it can reduce skin irritation.

[0075] (5-10) In this embodiment, the diaper 1 has the absorbent material 10 placed on the skin-contacting side, and the backsheet BS is laminated on the non-skin-contacting side opposite to the skin-contacting side. The layer of the absorbent material 10 containing cotton fibers has a bulk density of 0.005 to 6.0 g / cm³. ３ This is a densified cotton fiber sheet 12.

[0076] This diaper 1 has a skin-contacting surface made of a sheet containing cotton fibers, which reduces skin irritation.

[0077] (5-11) The method for manufacturing the absorbent body 10 of this embodiment is a method for manufacturing an absorbent body 10 having a compacted cotton fiber sheet 12. The manufacturing method involves using a roll press to produce a compacted cotton fiber sheet with a bulk density of 0.001 to 0.50 g / cm³. ３ The cotton fiber sheet 11 is compressed to a bulk density of 0.005 to 6.0 g / cm³. ３ The process includes a forming step of forming a compacted cotton fiber sheet 12.

[0078] In this method of manufacturing the absorbent material 10, cotton fibers are used to produce the absorbent material 10, thereby improving its absorbent performance. Furthermore, the absorbent material 10 produced by this method can reduce skin irritation.

[0079] Typically, when cotton is used in hygiene products, it is processed into spunlace nonwoven fabric. The processing of spunlace nonwoven fabric involves numerous steps, including loosening the raw cotton roll, carding, web formation, high-pressure water jet spraying, processing, drying, and winding, resulting in high material costs. In this method of manufacturing the absorbent body 10, the cotton fiber sheet 11 unwound from the raw cotton roll 20 is compacted using a roll press to form a compacted cotton fiber sheet 12. This reduces the cost of manufacturing the absorbent body 10 using cotton.

[0080] (5-12) The method for manufacturing the absorbent body 10 of this embodiment includes a placement step of placing an absorbent polymer 8 in the space SP between two compacted cotton fiber sheets 12.

[0081] In this method for manufacturing the absorbent body 10, the absorbent performance of the absorbent body 10 can be further improved by arranging the absorbent polymer 8.

[0082] (5-13) In the manufacturing method of the absorbent body 10 of this embodiment, in the arrangement step, the amount of absorbent polymer 8 per unit area that is arranged in the central region A1 of the central part of the compacted cotton fiber sheet 12 is greater than the amount of absorbent polymer 8 per unit area that is arranged in the peripheral region A2 around the central region A1.

[0083] In this method for manufacturing the absorbent body 10, the absorbent performance of the absorbent body 10 can be further improved by increasing the amount of absorbent polymer 8 placed in the central region A1 where a large amount of excrement adheres.

[0084] (5-14) The method for manufacturing the absorbent 10 of this embodiment further comprises a compaction step in which a third region located at the periphery of the compacted cotton fiber sheet 12 is pressurized and compacted when the laminated compacted cotton fiber sheet 12 is viewed along the thickness direction.

[0085] The absorbent material 10 and the absorbent polymer 8 swell when they absorb water. In particular, the degree of expansion is greater in the central region of the absorbent material 10 where a large amount of absorbent polymer 8 is located. In this method of manufacturing the absorbent material 10, the bonding strength in the peripheral region of the compacted cotton fiber sheet 12, where the degree of expansion is small, can be improved by applying pressure to the peripheral region. As a result, peeling and displacement of the compacted cotton fiber sheet 12 can be reduced.

[0086] (6) Modifications The following are modifications of the above embodiments. The following modifications may be combined as appropriate, as long as they do not contradict each other.

[0087] (6-1) Modification A The absorbent body 10 in the above embodiment is made of a compacted cotton fiber sheet 12. However, the absorbent body 10 is made of cotton fiber that has a bulk density of 0.001 to 0.50 g / cm³ before being compacted in step S5 in Figure 4A or step S15 in Figure 4B, which is unwound from the raw cotton roll 20. ３ The sheet within this range may be a cotton fiber sheet 11. Furthermore, the cotton fiber sheet 11 before compaction may be cut to a predetermined size and used as the absorbent body 10.

[0088] According to this modified example, since it is not necessary to produce a compacted cotton fiber sheet 12, the number of steps required for manufacturing the absorbent body 10 can be reduced.

[0089] (6-2) Modification B Different types of fibers may be arranged inside the mesh structure of cotton fibers. In this case, the proportion of cotton fibers is preferably 50% by weight or more.

[0090] For example, other fibers may be mixed in after the cotton fibers have been scouring and bleached in step S3 of Figure 4A. Alternatively, other fibers may be mixed in after impurities have been removed in step S12 of Figure 4B. The other fibers are, for example, short fibers different from cotton fibers, such as fibers obtained from eucalyptus. It is preferable that the other fibers are highly hydrophilic. In step S4 of Figure 4A or step S13 of Figure 4B, the cotton fibers mixed with other fibers are formed into a sheet, so that fibers of a different type from cotton fibers are arranged inside the mesh structure of the cotton fibers. At this time, the bulk density of the mixed state is 0.001 to 0.50 g / cm³. ３ It is processed in such a manner. A sheet mixed with other fibers, cut to a predetermined size, may also be used as the absorbent body 10.

[0091] Because cotton fibers have a long fiber length, when the bulk density is low, the voids formed by the mesh-like structure become large. By arranging other fibers inside the mesh-like structure of the cotton fibers, the voids become smaller, and the structure of the cotton fiber sheet 11 becomes more stable. In addition, by arranging highly hydrophilic fibers, the absorption performance of the absorbent material 10 is further improved.

[0092] (6-3) Modification C In the above modification B, a sheet with a predetermined bulk density may be formed by applying pressure to a sheet mixed with other fibers. The predetermined bulk density is 0.005 to 6.0 g / cm³ in the state in which the other fibers are mixed. ３ That is the case.

[0093] A sheet containing other fibers, which has been compressed and cut to predetermined dimensions, may also be used as the absorbent material 10.

[0094] (6-4) Modification D The absorbent polymer 8 may be placed inside the mesh structure of the cotton fibers.

[0095] For example, the absorbent polymer 8 may be mixed after the cotton fibers have been scouring and bleached in step S3 of Figure 4A. Alternatively, for example, the absorbent polymer 8 may be mixed after impurities have been removed in step S12 of Figure 4B. In step S4 of Figure 4A or step S13 of Figure 4B, the cotton fibers mixed with the absorbent polymer 8 are formed into a sheet, thereby distributing the absorbent polymer 8 within the mesh-like structure of the cotton fibers.

[0096] Alternatively, for example, the absorbent polymer 8 may be sprayed onto a cotton fiber sheet 11 unwound from a raw cotton roll 20, and then sucked from the opposite side of the sprayed side, thereby positioning the absorbent polymer 8 inside the mesh-like structure of the cotton fibers. Because cotton fibers have a long fiber length and the voids formed by the mesh-like structure are large, the absorbent polymer 8 is easily positioned inside the mesh-like structure.

[0097] In the above case, the bulk density of the cotton fibers excluding the absorbent polymer 8 is 0.001 to 0.50 g / cm³. ３ The material is processed in such a manner. A sheet mixed with the absorbent polymer 8 may be cut to a predetermined size and used as the absorbent material 10.

[0098] According to this modified example, the absorption performance of the absorbent material 10 can be further improved.

[0099] (6-5) Modification E In the above modification D, a sheet with a predetermined bulk density may be formed by applying pressure to the sheet mixed with the absorbent polymer 8. The predetermined bulk density is the bulk density of the cotton fibers excluding the absorbent polymer 8, and is 0.005 to 6.0 g / cm³. ３ That is the case.

[0100] A compacted sheet containing an absorbent polymer 8, which has been compacted and then cut to a predetermined size, may be used as the absorbent body 10.

[0101] (6-6) Modification F In the above modification B, an absorbent polymer 8 may be further arranged inside the mesh structure of the cotton fibers. By further arranging the absorbent polymer 8 inside the mesh structure of the cotton fibers which also contains other fibers, the voids formed by the mesh structure become even smaller, and the arrangement of the absorbent polymer 8 can be stabilized.

[0102] (6-7) Modified Example G In the above embodiment, the absorbent polymer 8 is placed in the space SP between two densified cotton fiber sheets 12. However, it is not limited to this, and it is sufficient if the absorbent polymer 8 is placed in at least one of the spaces SP between two adjacent densified cotton fiber sheets 12 among three or more densified cotton fiber sheets 12.

[0103] (6-8) Modification H In the above embodiment, the cotton fiber sheet 11 is roll-pressed and compacted so that the bulk density is 0.005 to 6.0 g / cm³ ３ A compacted cotton fiber sheet 12 is formed. At this time, embossing may be performed to partially press the cotton fiber sheet 11 in the thickness direction to create a predetermined shape.

[0104] (6-9) Modification I Another method for manufacturing the absorbent 10 will be explained with reference to Figure 8B.

[0105] First, a cotton fiber sheet 11 before compaction is fed out from the raw cotton roll 20 (step S31). After the absorbent polymer 8 is placed on the cotton fiber sheet 11 before compaction, pressure is applied to the cotton fiber sheet 11 to form a compacted cotton fiber sheet 12 with a predetermined bulk density (steps S32, S33). The compacted cotton fiber sheet 12 with the absorbent polymer 8 placed on it is cut to a predetermined size (step S34).

[0106] (6-10) Modification J Another method for manufacturing the absorbent 10 will be described with reference to Figure 8C.

[0107] First, the cotton fiber sheet 11 before densification is fed out from the raw cotton roll 20 (step S41a). Then, pressure is applied to the cotton fiber sheet 11 before densification to form a densified cotton fiber sheet 12 with a predetermined bulk density (step S42a). The contents of the processes in steps S41b and S42b are the same as the contents of the processes in steps S41a and S42a, so their explanation is omitted. The densified cotton fiber sheet 12 formed in step S42a is called the first densified cotton fiber sheet 12c. The densified cotton fiber sheet 12 formed in step S42b is called the second densified cotton fiber sheet 12d.

[0108] An absorbent polymer 8 is placed on the first compacted cotton fiber sheet 12c (step S43).

[0109] Next, the second densified cotton fiber sheet 12d is laminated on top of the absorbent polymer 8 (so that the absorbent polymer 8 is positioned between the first densified cotton fiber sheet 12c and the second densified cotton fiber sheet 12d) (step S44).

[0110] By applying pressure to predetermined positions of the first densified cotton fiber sheet 12c and the second densified cotton fiber sheet 12d, the first densified cotton fiber sheet 12c and the second densified cotton fiber sheet 12d are joined and integrated (step S45).

[0111] The integrated first densified cotton fiber sheet 12c and second densified cotton fiber sheet 12d are cut to predetermined dimensions (step S46).

[0112] (6-11) Modification K Another method for manufacturing the absorbent 10 will be described with reference to Figure 8D.

[0113] First, the cotton fiber sheet 11 before compaction is fed out from the raw cotton roll 20 (step S51). The cotton fiber sheet 11 before compaction is cut to a predetermined size (step S52). Hereinafter, the two cut cotton fiber sheets 11 before compaction will be referred to as the first cotton fiber sheet 11a and the second cotton fiber sheet 11b. The first cotton fiber sheet 11a and the second cotton fiber sheet 11b are the same size.

[0114] The absorbent polymer 8 is placed on the first cotton fiber sheet 11a (step S53).

[0115] Next, the second cotton fiber sheet 11b is laminated on top of the absorbent polymer 8 (so that the absorbent polymer 8 is positioned between the first cotton fiber sheet 11a and the second cotton fiber sheet 11b) (step S54).

[0116] By applying pressure to predetermined positions on the first cotton fiber sheet 11a and the second cotton fiber sheet 11b, the first cotton fiber sheet 11a and the second cotton fiber sheet 11b are joined and integrated (step S55).

[0117] (6-12) Modified Example L In the above embodiment, the cotton fiber sheet 11 is manufactured through a scouring and bleaching process, but the scouring and bleaching process does not have to be performed when manufacturing the cotton fiber sheet 11, as shown in Figure 10 (steps S61, S62, S63, and S64 in Figure 10 are the same as steps S1, S2, S4, and S5 in Figure 4A, respectively). Also, when manufacturing the cotton fiber sheet 11, degreasing may not be performed, and only bleaching may be performed. In other words, the cotton fibers contained in the absorbent 10 manufactured using the cotton fiber sheet 11 may be unbleached. Also, when manufacturing the cotton fiber sheet 11, bleaching may not be performed, and only degreasing may be performed. In other words, the cotton fibers contained in the absorbent 10 manufactured using the cotton fiber sheet 11 may be unbleached.

[0118] Furthermore, if the absorbent body 10 is composed of multiple cotton fiber sheets, some of the cotton fiber sheets may be undegreased and some may be degreased. In other words, some of the cotton fibers contained in the absorbent body 10 manufactured using the cotton fiber sheets 11 may be undegreased. For example, although not limiting the configuration, if the absorbent body 10 includes a first densified cotton fiber sheet 12a and a second densified cotton fiber sheet 12b, the densified cotton fiber sheet that is placed on the non-skin side of the first densified cotton fiber sheet 12a and the second densified cotton fiber sheet 12b may be undegreased.

[0119] Furthermore, if the absorbent body 10 is composed of multiple cotton fiber sheets, and all cotton fiber sheets are degreased, the degree of degreasing of each cotton fiber sheet may differ.

[0120] The cotton raw material used in the manufacture of the cotton fiber sheet 11 (for example, in step S1 in Figure 4 and step S61 in Figure 10) is, in one example, a cotton block. The cotton raw material may be raw cotton (undegreased and unbleached), degreased cotton, or bleached cotton. For example, a cotton block is brought into the manufacturing site of the absorbent body 10, and it is unraveled to manufacture the cotton fiber sheet 11. The form of the cotton raw material supplied to the manufacturing site of the absorbent body 10 can be determined as appropriate. For example, the form of the cotton raw material supplied to the manufacturing site of the absorbent body 10 may be cotton wound in a roll, rather than a cotton block.

[0121] Furthermore, the manufacturing site of the absorbent material 10 may be supplied with raw cotton rolls that have been manufactured elsewhere in advance (processing up to step S4 in Figure 4 or up to step S63 in Figure 10), or densified cotton fiber sheets 11 that have been processed up to step S5 in Figure 4 or up to step S64 in Figure 10.

[0122] <Addendum> Finally, the technical concepts that can be understood from the above embodiments are added below.

[0123] The absorbent material in the first aspect contains cotton fibers having a mesh-like structure and has a bulk density of 0.001 to 6.0 g / cm³. ３ It is equipped with seats.

[0124] The absorbent material in the second view is the absorbent material in the first view, in which a different type of fiber than cotton fibers is arranged inside the mesh structure.

[0125] The absorbent material of the third aspect is the absorbent material of the first or second aspect, wherein an absorbent polymer is arranged inside a mesh-like structure.

[0126] The absorbent material of the fourth aspect is an absorbent material of any of the first or third aspects, and the sheet containing cotton fibers has a bulk density of 0.005 to 6.0 g / cm³. ３ It is a compacted sheet.

[0127] The absorbent from the fifth perspective is the absorbent from the fourth perspective, and is composed of multiple compacted sheets laminated together.

[0128] The absorbent in the sixth aspect is the absorbent in the fifth aspect, further comprising an absorbent polymer disposed in at least one of the spaces between two adjacent compacted sheets.

[0129] The seventh aspect of the absorbent is the sixth aspect of the absorbent, and when viewed along the stacking direction of the compacted sheet, the space includes a first region located in the center of the compacted sheet and a second region located around the first region. The amount of absorbent polymer per unit area located in the first region is greater than the amount of absorbent polymer per unit area located in the second region.

[0130] The absorbent in the eighth aspect is an absorbent according to any of the fourth to seventh aspects, and the compacted sheet has a first compacted portion and a second compacted portion. The second compacted portion has a higher bulk density than the first compacted portion.

[0131] The absorber in the ninth view is the absorber in the eighth view, wherein the second compaction portion is formed in a third region located at the periphery of the compaction sheet when viewed along the thickness direction of the compaction sheet. The first compaction portion is formed in a fourth region located at the center of the compaction sheet when viewed along the thickness direction of the compaction sheet.

[0132] The absorbent material of the tenth aspect is the absorbent material of any of the first to ninth aspects, and the cotton fibers include undegreased cotton fibers.

[0133] The absorbent article of the eleventh aspect comprises an absorbent material according to either the first or tenth aspect, a top sheet, and a back sheet. The absorbent material is positioned between the top sheet and the back sheet.

[0134] The absorbent article in the 12th aspect is the absorbent article in the 11th aspect, and the top sheet has a bulk density of 0.005 to 6.0 g / cm³. ３ It is composed of compacted sheets.

[0135] The absorbent article of the 13th perspective has an absorbent material from either the 1st to the 10th perspective placed on the skin-contacting side, and a backsheet laminated on the non-skin-contacting side opposite the skin-contacting side.

[0136] The fourteenth aspect concerns a method for manufacturing an absorbent, which is a method for manufacturing an absorbent having a compacted sheet. The method for manufacturing the absorbent involves using a roll press to produce a material containing cotton fibers with a bulk density of 0.01 to 0.50 g / cm³. ３ The sheet is compressed, and the bulk density is 0.07 to 0.50 g / cm³. ３ The process includes a forming step of forming a compacted sheet.

[0137] The method for manufacturing an absorbent according to the 15th aspect is the method for manufacturing an absorbent according to the 14th aspect, comprising the step of arranging an absorbent polymer in the space between two compacted sheets.

[0138] The method for producing an absorbent according to the 16th aspect is the method for producing an absorbent according to the 15th aspect, wherein in the arrangement step, the amount of absorbent polymer per unit area arranged in the first region in the central part of the compacted sheet is greater than the amount of absorbent polymer per unit area arranged in the second region surrounding the first region.

[0139] The method for manufacturing an absorbent according to the 17th aspect is a method for manufacturing an absorbent according to any of the 14th to 16th aspects, further comprising a compaction step in which a third region located at the periphery of a laminated compacted sheet is pressurized and compacted when the compacted sheet is viewed along the thickness direction.

[0140] 1 Diapers, absorbent articles 2 Absorbent body 8 Absorbent polymer 10 Absorbent body 11 Cotton fiber sheet, sheet 11a First cotton fiber sheet, cotton fiber sheet, sheet 11b Second cotton fiber sheet, cotton fiber sheet, sheet 12 Compressed cotton fiber sheet, compressed sheet 12a First compressed cotton fiber sheet, compressed cotton fiber sheet, compressed sheet 12b Second compressed cotton fiber sheet, compressed cotton fiber sheet, compressed sheet 12c First compressed cotton fiber sheet, compressed cotton fiber sheet, compressed sheet 12d Second compressed cotton fiber sheet, compressed cotton fiber sheet, compressed sheet 13 First compressed section 14 Second compressed section A1 Central region, first region A2 Peripheral region, second region BS Back sheet TS Top sheet

Claims

1. Contains cotton fibers having a mesh-like structure, with a bulk density of 0.001 to 6.0 g / cm³. ３ An absorbent material equipped with a sheet.

2. The absorbent material according to claim 1, wherein a different type of fiber than the cotton fiber is arranged inside the mesh-like structure.

3. The absorbent material according to claim 1 or 2, wherein an absorbent polymer is arranged inside the mesh-like structure.

4. The sheet containing the cotton fibers has a bulk density of 0.005 to 6.0 g / cm³. ３ The absorbent according to any one of claims 1 to 3, which is a compacted sheet.

5. The absorbent according to claim 4, wherein a plurality of the compacted sheets are laminated together.

6. The absorbent according to claim 5, further comprising an absorbent polymer disposed in at least one of the spaces between two adjacent compacted sheets.

7. The absorbent according to claim 6, wherein, when viewed along the stacking direction of the compacted sheet, the space includes a first region located in the center of the compacted sheet and a second region located around the first region, and the amount of absorbent polymer per unit area located in the first region is greater than the amount of absorbent polymer per unit area located in the second region.

8. The absorbent according to any one of claims 4 to 7, wherein the compacted sheet has a first compacted portion and a second compacted portion, and the second compacted portion has a greater bulk density than the first compacted portion.

9. The absorbent according to claim 8, wherein the second compaction portion is formed in a third region located at the periphery of the compaction sheet when viewed along the thickness direction of the compaction sheet, and the first compaction portion is formed in a fourth region located at the center of the compaction sheet when viewed along the thickness direction of the compaction sheet.

10. The absorbent body according to any one of claims 1 to 9, wherein the cotton fibers include undegreased cotton fibers.

11. An absorbent article comprising an absorbent body according to any one of claims 1 to 10, a top sheet and a back sheet, wherein the absorbent body is disposed between the top sheet and the back sheet.

12. The top sheet has a bulk density of 0.005 to 6.0 g / cm³. ３ The absorbent article according to claim 11, comprising a compacted sheet.

13. An absorbent article comprising an absorbent material according to any one of claims 1 to 10 arranged on the skin-contacting side, and a back sheet laminated on the non-skin-contacting side opposite to the skin-contacting side.

14. A method for manufacturing an absorbent having a compacted sheet, wherein a roll press is used to produce a compacted sheet containing cotton fibers with a bulk density of 0.001 to 0.50 g / cm³. ３ The sheet is compressed, and the bulk density is 0.005 to 6.0 g / cm³. ３ A method for manufacturing an absorbent, comprising the step of forming the compacted sheet.

15. A method for producing an absorbent according to claim 14, comprising the step of arranging an absorbent polymer in the space between two compacted sheets.

16. The method for producing an absorbent according to claim 15, wherein in the arrangement step, the amount of absorbent polymer per unit area arranged in the first region in the central part of the compacted sheet is greater than the amount of absorbent polymer per unit area arranged in the second region surrounding the first region.

17. A method for manufacturing an absorbent according to any one of claims 14 to 16, further comprising a compaction step of pressurizing a third region located at the periphery of the compacted sheet when the stacked compacted sheets are viewed along the thickness direction.

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