absorbent articles

Abstract

To provide an environmentally friendly absorbent article in which a sheet made of recycled pulp does not break even after long-term use. [Solution] The absorbent article 1 has recycled sheets 8, 9 and composite sheets Z1, Z2 in which adjacent separate sheets 4, 5 are bonded to the recycled sheets, the recycled pulp content in the recycled sheets is less than 15% by weight, when the composite sheet is pulled in the direction of the fiber orientation of the recycled sheet, the tensile force per unit width at which the recycled sheet in the composite sheet starts to break is higher than the tensile force per unit width at which the separate sheet in a single sheet starts to break when pulled in the direction of orientation, the recycled sheet and the separate sheet in the composite sheet are bonded with a hot melt adhesive, and there is no heat embossing to bond the recycled sheet and the separate sheet to each other.

Description

[Technical Field]

[0001] The present invention relates to absorbent articles. [Background technology]

[0002] In recent years, efforts to achieve the Sustainable Development Goals (SDGs) have been required, and in response to this, efforts to make effective use of resources are being promoted. For example, technologies are known for recovering and recycling pulp fibers, superabsorbent resins (superabsorbent polymers), and the like from used absorbent articles. Among such material recycling methods, there is also a demand for horizontal recycling, such as recovering raw pulp from used disposable diapers and manufacturing disposable diapers again. For example, Patent Document 1 discloses a paper composition and recycled paper containing pulp and absorbent resins recovered from absorbent articles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-75819 Summary of the Invention [Problem to be solved by the invention]

[0004] The recycled paper described in Patent Document 1 contains a low-molecular-weight absorbent resin, which increases its strength and allows it to be used as absorbent sanitary paper, kraft paper, copy paper, and other products for applications such as disposable diapers and sanitary products. However, when such recycled paper is used as a material for absorbent goods, it is required to have a material strength that will not break even after prolonged use. In particular, sheet materials made from recycled pulp, which is made reusable by extracting raw pulp from used diapers, tend to have shorter pulp fiber lengths due to the washing process during the recycling process, and may also contain trace amounts of foreign matter. As a result, the bonds between the fibers weaken during the process of forming recycled pulp into a sheet, and the sheet material containing this recycled pulp may have reduced strength. To maintain strength, it is possible to use a sheet material with a reduced recycled pulp content, but although such a sheet material has relatively high strength for a recycled sheet, it may be damaged if used in an absorbent article for a long period of time, and therefore further strength is required.

[0005] The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide an absorbent article that uses recycled sheet material containing recycled pulp as a constituent material of the absorbent article and reduces the risk of the sheet material being damaged even when used for a long period of time. [Means for solving the problem]

[0006] The main idea for achieving the above object is an absorbent article comprising a recycled sheet containing recycled pulp recycled from disposable absorbent articles, the absorbent article comprising a composite sheet formed by joining the recycled sheet to a separate sheet adjacent to the recycled sheet in the thickness direction of the absorbent article, the recycled pulp content in the recycled sheet being less than 15% by weight, the tensile force per unit width at which the recycled sheet in the composite sheet begins to break when the composite sheet is pulled in the fiber orientation direction of the recycled sheet is higher than the tensile force per unit width at which the separate sheet in the composite sheet begins to break when the separate sheet alone is pulled in the fiber orientation direction, the recycled sheet and the separate sheet in the composite sheet are joined by a hot melt adhesive, and the absorbent article does not have a heat embossing that joins the recycled sheet and the separate sheet to each other. Other features of the present invention will become apparent from the description of this specification and the accompanying drawings. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an absorbent article in which the sheet made from recycled pulp will not break even after long-term use, and which is environmentally friendly. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic plan view of a disposable diaper 1 as an absorbent article according to a first embodiment in an unfolded and stretched state, as viewed from the skin-facing side. [Figure 2] FIG. 2 is a cross-sectional view taken along the line AA shown in FIG. [Figure 3] 1 is a table showing the evaluation results of the tensile strength of each sheet. [Figure 4] 1 shows an example of a load-elongation diagram in a tensile test of the above-mentioned composite sheet B. [Figure 5] 10 is a plan view showing the application area of ​​adhesive that joins the topsheet 4 and the skin-side core wrap sheet 8. FIG. [Figure 6] 10 is a plan view showing the application area of ​​adhesive that joins the non-skin side core wrap sheet 9 and the back sheet 5. FIG. [Figure 7] 6, and further shows an adhesive that bonds the absorbent core 3 and the non-skin-side core wrap sheet 9. In FIG. [Figure 8] FIG. 1 is a schematic plan view of an absorbent pad 2 serving as an absorbent article according to a second embodiment, in an unfolded and stretched state, as viewed from the skin-facing side. [Figure 9] FIG. 9 is an exploded perspective view of the main part of the absorbent pad 2 shown in FIG. [Figure 10] FIG. 9 is a cross-sectional view taken along the line BB shown in FIG. [Figure 11] FIG. 2 is a plan view showing a second absorbent core 33b and a second core wrap sheet 39 of the absorbent pad 2 in an unfolded state. DETAILED DESCRIPTION OF THE INVENTION

[0009] At least the following matters will become clear from the description of this specification and the accompanying drawings. The absorbent article is characterized in that it comprises a recycled sheet containing recycled pulp recycled from disposable absorbent articles, and has a composite sheet formed by joining the recycled sheet to a separate sheet adjacent to the recycled sheet in the thickness direction of the absorbent article, the recycled pulp content in the recycled sheet is less than 15% by weight, and when the composite sheet is pulled in the fiber orientation direction of the recycled sheet, the tensile force per unit width at which the recycled sheet in the composite sheet begins to break is higher than the tensile force per unit width at which the separate sheet alone begins to break when pulled in the fiber orientation direction.

[0010] In such an absorbent article, by joining the recycled sheet and the separate sheet, the strength of the recycled sheet itself in the joined composite sheet becomes strong enough to withstand a tensile force greater than that at which the separate sheet alone begins to break, thereby improving the strength of the recycled sheet. By making the recycled pulp content less than 15% by weight, the recycled sheet can maintain this strength, reducing the risk of damage to the recycled sheet even when used in an absorbent article for a long period of time.

[0011] In such an absorbent article, it is desirable that in the composite sheet, the orientation direction of the fibers of the recycled sheet and the orientation direction of the fibers of the separate sheet are the same direction, and that the maximum elongation in the orientation direction of the fibers of the separate sheet is lower than the maximum elongation in a direction perpendicular to the orientation direction of the fibers.

[0012] In such an absorbent article, the separate sheet is less likely to tear when force is applied to the composite sheet if the fiber orientation direction of the recycled sheet is aligned with the direction of the separate sheet with the highest maximum elongation, i.e., the direction in which the fiber orientation direction of the recycled sheet is aligned with the direction in which the maximum elongation of the separate sheet is lower, i.e., the direction in which the separate sheet is less likely to stretch, compared to when the separate sheet is aligned with the direction of the maximum elongation of the separate sheet, and as a result, the recycled sheet is less likely to tear.

[0013] In such an absorbent article, it is desirable that the tensile force per unit width when the length of the separate sheet after stretching in the fiber orientation direction becomes 105% of the length of the separate sheet before stretching is higher than the tensile force per unit width when the recycled sheet begins to break when the recycled sheet alone is pulled in the fiber orientation direction.

[0014] In such an absorbent article, the separate sheet does not break even when stretched by 5%, and does not break before the recycled sheet alone. By joining the separate sheet, which has such strength as a material, to the recycled sheet, the strength of the recycled sheet in the composite sheet can be increased.

[0015] In such an absorbent article, it is preferable that the recycled sheet contains a thermoplastic resin.

[0016] Such an absorbent article can reduce the risk of breakage of the recycled sheet containing thermoplastic resin.

[0017] In such an absorbent article, it is desirable that the separate sheet contains a thermoplastic resin, and that the core wrap sheet and the separate sheet are heat-sealed.

[0018] According to such an absorbent article, the strength of the recycled sheet in the composite sheet can be increased by heat-sealing the thermoplastic resin of the recycled sheet and the thermoplastic resin of the separate sheet.

[0019] In such an absorbent article, it is desirable that the thermoplastic resin of the recycled sheet and the thermoplastic resin of the separate sheet are the same type of thermoplastic resin.

[0020] According to such an absorbent article, the strength of the recycled sheet in the composite sheet can be increased by heat fusion of the same type of thermoplastic resin.

[0021] In such an absorbent article, it is preferable that the recycled sheet and the separate sheet in the composite sheet are joined together by a hot melt adhesive.

[0022] In such an absorbent article, the tensile strength at the time of initiation of breakage of the recycled sheet in the composite sheet can be increased by joining with hot melt.

[0023] In such an absorbent article, it is desirable that the hot melt adhesive is applied in a planar manner at least in a part thereof.

[0024] According to such an absorbent article, the strength of the recycled sheet can be further increased in the areas where the hot melt is applied without any gaps (solid application areas).

[0025] In such an absorbent article, it is desirable that the composite sheet has a non-bonded region where the recycled sheet and the separate sheet are not bonded by the hot melt adhesive.

[0026] With such an absorbent article, if hot melt is applied to the entire surface without any gaps, the composite sheet may become hard, but by having non-bonded areas, softness can be maintained and a balance between strength and hardness can be achieved.

[0027] In such an absorbent article, when unfolded, the orientation direction of the fibers is the longitudinal direction of the absorbent article, the direction perpendicular to the longitudinal direction is the width direction, and the area of ​​the composite sheet where the recycled sheet and the separate sheet are joined by the hot melt adhesive is defined as the joined area, and it is desirable that the total length of the joined area in the width direction be longer than the total length of the non-jointed area in the width direction.

[0028] In such an absorbent article, the strength of the composite sheet can be improved by increasing the area fixed by the hot melt adhesive, making the recycled sheet less likely to tear.

[0029] In such an absorbent article, when the article is unfolded, the orientation direction of the fibers is the longitudinal direction of the absorbent article, and when the direction perpendicular to the longitudinal direction is the width direction, it is desirable that the length of the continuous hot melt adhesive in the composite sheet is longer in the longitudinal direction than in the width direction.

[0030] In such an absorbent article, the recycled sheet has a higher tensile strength in the longitudinal direction, which is the fiber orientation direction, than in the width direction, and by providing a long, continuous hot melt adhesive in the longitudinal direction, which is the fiber orientation direction, the recycled sheet can be made more resistant to tearing.

[0031] In such an absorbent article, it is desirable that at least a portion of the joining area where the recycled sheet and the separate sheet are joined by the hot melt adhesive is provided over the entire longitudinal area of ​​the recycled sheet.

[0032] In such an absorbent article, the recycled sheet has a bonded area of ​​hot melt adhesive over the entire area in the longitudinal direction where the tensile strength is high, making the recycled sheet more resistant to tearing.

[0033] It is desirable that such an absorbent article has an absorbent core, a skin-side composite sheet which is the composite sheet arranged on the skin side of the absorbent core in the thickness direction, and a non-skin-side composite sheet which is the composite sheet arranged on the non-skin side of the absorbent core in the thickness direction, and that the recycled sheet of the skin-side composite sheet is a skin-side core wrap sheet arranged adjacent to the skin side of the absorbent core, and that the recycled sheet of the non-skin-side composite sheet is a non-skin-side core wrap sheet arranged adjacent to the non-skin side of the absorbent core.

[0034] In such absorbent articles, the absorbent core swells when it absorbs liquid, and if a core wrap sheet is provided to wrap the absorbent core, the expansion of the core applies force to the core wrap sheet, which may tear the core wrap sheet at the side portions wrapping the core. By arranging the core wrap sheet separately on the skin side and the non-skin side, the load on the core wrap sheet can be reduced, thereby reducing the risk of tearing.

[0035] In such an absorbent article, the separate sheet of the skin-side composite sheet is a liquid-permeable sheet member, and the separate sheet of the non-skin-side composite sheet is a liquid-impermeable sheet member, and it is desirable that when the non-skin-side composite sheet is pulled in the fiber orientation direction of the recycled sheet, the tensile force per unit width at which the recycled sheet in the non-skin-side composite sheet begins to break is higher than the tensile force per unit width at which the recycled sheet in the skin-side composite sheet begins to break when the skin-side composite sheet is pulled in the fiber orientation direction of the recycled sheet.

[0036] In such an absorbent article, the tensile force at which the recycled sheet in the composite sheet begins to break increases as the tensile force at which the joined separate sheet begins to break increases. Because the non-skin-side composite sheet is joined to a liquid-impermeable sheet member (separate sheet), the recycled sheet in the non-skin-side composite sheet has a higher tensile force at which it begins to break than the recycled sheet in the skin-side composite sheet. Therefore, compared to when the tensile force per unit width at which the recycled sheet in the non-skin-side composite sheet begins to break is lower than the tensile force per unit width at which the recycled sheet in the skin-side composite sheet begins to break, the leakage prevention effect can be further improved when the tensile force per unit width at which the recycled sheet in the non-skin-side composite sheet begins to break is higher than the tensile force per unit width at which the recycled sheet in the skin-side composite sheet begins to break.

[0037] In such an absorbent article, the separate sheet of the non-skin side composite sheet is arranged adjacent to the non-skin side of the non-skin side core wrap sheet, the non-skin side composite sheet has a non-bonded area where the non-skin side core wrap sheet and the separate sheet are not bonded with hot melt adhesive, the absorbent core and the non-skin side core wrap sheet have a core bonded area where they are bonded to each other with the hot melt adhesive, and when the absorbent article is viewed in a planar state in an unfolded state, it is desirable that the non-bonded area has a portion that overlaps with the core bonded area.

[0038] In such an absorbent article, the non-bonded area where hot melt adhesive is not applied may have reduced strength, but by having an overlapping portion with the core bonded area where the absorbent core and the non-skin side core wrap sheet are bonded, the reduction in strength can be suppressed.

[0039] It is desirable that such an absorbent article has a first absorbent core containing at least a superabsorbent polymer and a second absorbent core containing at least a superabsorbent polymer, wherein the mass ratio of the superabsorbent polymer contained in the first absorbent core is greater than the mass ratio of the superabsorbent polymer contained in the second absorbent core, and wherein a first recycled sheet, which is the recycled sheet, is provided as a core wrap sheet arranged so as not to wrap around the first absorbent core, and a second recycled sheet, which is the recycled sheet, is provided as a core wrap sheet arranged so as to wrap around the second absorbent core.

[0040] In such an absorbent article, by forming the core wrap sheet of the first absorbent core, which has a large amount of superabsorbent polymer, in a form that does not wrap around the first absorbent core, the burden on the core wrap sheet of the first absorbent core, which has a large amount of superabsorbent polymer and is more likely to swell, is reduced, and the risk of the core wrap sheet (first recycled sheet) tearing can be reduced.

[0041] In such an absorbent article, it is desirable that the recycled sheet contains a thermoplastic resin, and that at least a portion of the second recycled sheet has an overlapping area where the recycled sheets overlap each other when viewed in a plane of the absorbent article in an unfolded state, and that the recycled sheets are heat-fused to each other in the overlapping area.

[0042] In such an absorbent article, the recycled sheets are heat-sealed to each other, which increases the strength of the recycled sheets and further reduces the risk of tearing.

[0043] ===First Embodiment=== <Basic structure of diaper 1> The following description will be given taking as an example a tape-type disposable diaper for adults (hereinafter also referred to as diaper 1) as an example of an absorbent article according to the first embodiment. However, the absorbent article is not limited to the above, and can also be applied as a tape-type disposable diaper for children, a urine absorption pad, a sanitary product, etc.

[0044] Fig. 1 is a schematic plan view of a disposable diaper 1 as an absorbent article according to a first embodiment in an unfolded and stretched state, as seen from the skin-facing side. Fig. 2 is a cross-sectional view taken along line AA shown in Fig. 1.

[0045] As shown in Fig. 1, the diaper 1 has a longitudinal direction, a width direction, and a thickness direction in a flattened and stretched state. The diaper 1 is divided into three regions in the longitudinal direction: a ventral waistband 1A that contacts the wearer's ventral region; a dorsal waistband 1C that contacts the wearer's dorsal region; and a crotch region 1B that is located between the ventral waistband 1A and the dorsal waistband 1C in the longitudinal direction. As shown in Fig. 2, the direction in which the components constituting the diaper 1 are layered is referred to as the thickness direction. In the thickness direction, the side that contacts the wearer is referred to as the skin side, and the opposite side is referred to as the non-skin side.

[0046] The "unfolded state" of the diaper 1 refers to the state in which the diaper 1 is unfolded in its longitudinal direction and laid out flat. The "stretched state" of the diaper 1 refers to the state in which the entire diaper 1 (the entire product) is stretched without wrinkles, specifically, the state in which the dimensions of each component constituting the diaper 1 (e.g., the inner and outer leakage-proof elastic members 171, 181, the leg elastic members 16, the absorbent core 3, etc., described below) are stretched to the extent that they match or are close to the dimensions of the individual components (i.e., the dimensions when the elastic properties of the elastic members are not expressed).

[0047] As shown in FIG. 2, the diaper 1 includes an absorbent core 3, a top sheet 4 provided on the skin side of the absorbent core 3 in the thickness direction, a back sheet 5 and an outer sheet 6 provided on the non-skin side of the absorbent core 3 in the thickness direction, and a pair of side sheets 7.

[0048] The top sheet 4 may be any liquid-permeable sheet, such as an air-through nonwoven fabric or a spunbond nonwoven fabric. The back sheet 5 may be any liquid-impermeable sheet, such as a synthetic resin film or a hydrophobic SMS nonwoven fabric. The top sheet 4 and the back sheet 5 contain a thermoplastic resin (polyethylene (PE), polypropylene (PP), etc.).

[0049] The pair of side sheets 7 are sheets (e.g., nonwoven fabrics) that extend outward in the width direction from both widthwise edges on the skin-facing side of the top sheet 4. The outer sheet 6 is a liquid-impermeable sheet that is positioned closer to the skin than the back sheet 5 in the thickness direction, and forms the outer shape of the diaper 1, i.e., a shape in which the longitudinal center (crotch portion 1B) is narrowed inward in the width direction.

[0050] An example of the absorbent core 3 is one in which liquid-absorbent fibers such as pulp containing SAP (super absorbent polymer) are molded into a predetermined shape. In this embodiment, a liquid-permeable skin-side core wrap sheet 8 is disposed adjacent to the skin side of the absorbent core 3, and a liquid-permeable non-skin-side core wrap sheet 9 is disposed adjacent to the non-skin side of the absorbent core 3. The skin-side core wrap sheet 8 and the non-skin-side core wrap sheet 9 are made of, for example, tissue or the like, and details will be described later.

[0051] As shown in FIG. 1 , the diaper 1 also includes flap portions 10 extending outward in the width direction from the back waist portion 1C. The flap portions 10 include a base sheet 11 and a first fastening member 12 and a second fastening member 13 bonded to the base sheet 11. The base sheet 11 is bonded between the side sheet 7 and the outer sheet 6. The first fastening member 12 and the second fastening member 13 are spaced apart in the longitudinal direction and configured to be fastened to target portions 14 provided on the ventral waist portion 1A when the diaper 1 is worn. Examples of the first fastening member 12 and the second fastening member 13 include hook members. Note that one fastening member may be provided on each side. Alternatively, the diaper 1 may not include the base sheet 11 of the flap portions 10, but the side sheet 7 and the outer sheet 6 may extend outward in the width direction, and fastening members may be bonded to the side sheet 7.

[0052] The diaper 1 has longitudinally stretchable leg elastic members 16 on both widthwise sides (see FIG. 2). Three leg elastic members 16 are provided on each side, spaced apart in the widthwise direction. More specifically, the innermost leg elastic member 16 in the widthwise direction is disposed between the topsheet 4 and the backsheet 5. The remaining two leg elastic members 16 are disposed between the sidesheet 7 and the backsheet 5. The number of leg elastic members 16 is not particularly limited.

[0053] The diaper 1 also has inner leakage preventing gathers 17 and outer leakage preventing gathers 18. The inner leakage preventing gathers 17 and the outer leakage preventing gathers 18 are configured to be able to stand up on the wearer's skin side, and are provided in pairs on the left and right. The inner leakage preventing gathers 17 are so-called inward-leaking gathers, and the outer leakage preventing gathers 18 are so-called outward-leaking gathers. The inner leakage preventing gathers 17 are provided widthwise inward of the outer leakage preventing gathers 18 and the leg-hole elastic members 16. It is sufficient that at least a portion of the inner leakage preventing gathers 17 is located widthwise inward of the outer leakage preventing gathers 18. The diaper 1 is only required to have at least the outer leakage preventing gathers 18, and is not necessarily required to have the inner leakage preventing gathers 17.

[0054] The inner leakage preventing gathers 17 are formed by folding the topsheet 4, as shown in Fig. 2. Specifically, the inner leakage preventing gathers 17 are formed by folding the topsheet 4 from the outside in the width direction to the inside and toward the skin at folding line f1 shown in Fig. 2, and folding the topsheet 4 back from the inside in the width direction to the outside and away from the skin at folding line f2, and providing an inner leakage preventing elastic member 171 that stretches in the longitudinal direction at the folded back portion. An example of the inner leakage preventing elastic member 171 is rubber thread.

[0055] As shown in Fig. 2, the outer leakage preventing gathers 18 are formed by folding the side sheet 7. Specifically, the outer leakage preventing gathers 18 are formed by folding the side sheet 7 from the inside to the outside in the width direction and toward the skin at folding line f3 shown in Fig. 2, and folding the side sheet 7 back from the outside to the inside in the width direction and away from the skin at folding line f4, and providing an outer leakage preventing elastic member 181 that stretches in the longitudinal direction at the folded back portion. An example of the outer leakage preventing elastic member 181 is rubber thread. The inner leakage preventing gathers 17 and the outer leakage preventing gathers 18 can prevent side leakage of excrement.

[0056] Waist gathers 22 formed by a plurality of waist elastic members 21 are arranged at the longitudinal ends and widthwise center of the back waist portion 1C of the diaper 1. The waist gathers 22 allow the diaper 1 to conform to the shape of the wearer's waist when worn, and also prevent the diaper 1 from shifting out of position.

[0057] <Skin side and non-skin side core wrap sheets 8 and 9> The skin-side core wrap sheet 8 and the non-skin-side core wrap sheet 9 in this embodiment are recycled sheets containing recycled pulp recycled from used disposable absorbent articles (e.g., used disposable diapers). Generally, absorbent articles require strong materials to prevent the absorbent core from being exposed to the outside after extended use. Meanwhile, sheets containing recycled pulp, which is made reusable through a recycling process using raw pulp extracted from collected used disposable diapers, are characterized by the fact that the fiber length of the recycled pulp shortens during processes such as washing. This reduces the material strength, and for example, when a sheet containing recycled pulp is used as a core wrap sheet, there is a risk that the core wrap sheet will break and expose the absorbent core after extended use of the absorbent article.

[0058] In this regard, first, the diaper 1 has a composite sheet formed by joining a separate sheet adjacent to the recycled sheet in the thickness direction of the diaper 1 and the recycled sheet. Specifically, the separate sheet opposite the skin-side core wrap sheet 8 (recycled sheet) is the top sheet 4, and the skin-side core wrap sheet 8 and the top sheet 4 are joined to form a composite sheet. In other words, the diaper 1 has a skin-side composite sheet Z1, which is a composite sheet arranged on the skin side in the thickness direction of the absorbent core 3. Furthermore, the separate sheet opposite the non-skin-side core wrap sheet 9 (recycled sheet) is the back sheet 5, and the non-skin-side core wrap sheet 9 and the back sheet 5 are joined to form a composite sheet. In other words, the diaper 1 has a non-skin-side composite sheet Z2, which is a composite sheet arranged on the non-skin side in the thickness direction of the absorbent core 3.

[0059] Here, in order to confirm whether the material strength is increased when a recycled sheet containing recycled pulp with short fiber length is joined to a separate sheet to form a composite sheet, tests were conducted using the following method on each of the recycled sheet, the separate sheet, and the composite sheet.

[0060] (Evaluation method) The materials used for evaluation include: Recycled sheet containing 15% recycled pulp by weight (skin side core wrap sheet 8) An example of the surface sheet 4 (separate sheet) is polypropylene spunbond nonwoven fabric (PPSB). An example of the surface sheet 4 (separate sheet) is an air-through nonwoven fabric. As an example of the skin-side composite sheet Z1, composite sheet A (adhesive application amount 4g / m) was prepared by bonding the above-mentioned 1) and 2) with a hot melt adhesive. 2 Apply in a spiral pattern As an example of the skin-side composite sheet Z1, composite sheet B (adhesive application amount 4g / m) was prepared by bonding the above-mentioned 1) and 3) with a hot melt adhesive. 2 Apply in a spiral pattern We have prepared the following. Each of the sheets 1) to 5) above was cut into a size of 25 mm x 100 mm to prepare five samples of each sheet. To measure the strength of each sheet in the fiber orientation direction, the length of each sheet in the fiber orientation direction was set to 100 mm. For example, when the material is a nonwoven fabric, the constituent fibers are aligned in the direction (MD) along which the nonwoven fabric web is conveyed during production, so the fiber orientation direction refers to the direction along which the constituent fibers of such a material run. The tensile strength of a material in the orientation direction of the constituent fibers (MD direction of the web) is generally higher than the tensile strength in the direction perpendicular to the orientation direction of the constituent fibers (CD direction of the web). In other words, the fiber orientation direction refers to the direction in which the strength of the material is higher, either the longitudinal direction or the width direction of the diaper 1. In this embodiment, in the unfolded state shown in FIG. 1 , the fiber orientation direction is the longitudinal direction of the diaper 1, and the direction perpendicular to the orientation direction of the constituent fibers is the width direction.

[0061] The samples were then measured for tensile strength using a tensile testing machine (Shimadzu Corporation, Autograph Model AGS-1KNG, etc.) by pulling the samples in the fiber orientation direction at a speed of 100 mm / min. Similar measurements were performed five times for each sample to calculate the maximum tensile force. The average of these measurements was used as the maximum tensile force (tensile strength) for each of sheets 1) to 5). Figure 3 shows the evaluation results for the tensile strength of each sheet. Since the standard width of each sheet was 25 mm, the denominator for the maximum tensile force unit is 25 mm. Figure 4 also shows an example of a load-elongation diagram from the tensile test of the composite sheet B described above. The diagram in Figure 4 shows the results of a sample close to the average maximum tensile force among five measurements of the composite sheet B sample. The peak (maximum point) shown in the diagram in Figure 4 is the maximum tensile force, and this peak is the point at which the sheet begins to break; in reality, breakage occurs after the maximum tensile force is reached.

[0062] Referring to Figure 3, the maximum tensile strength of the recycled sheet alone (1) was 9.2 N / 25 mm, while the maximum tensile strength of composite sheet A (4) made by bonding the recycled sheet with PPSB was 27.9 N / 25 mm, and the maximum tensile strength of composite sheet B (5) made by bonding the recycled sheet with an air-through nonwoven fabric was 25.5 N / 25 mm, showing increased strength in all cases. It can also be seen that the maximum tensile strength of composite sheet A is higher than the maximum tensile strength of the separate sheet (2) PPSB alone (24.1 N / 25 mm), and the maximum tensile strength of composite sheet B is higher than the maximum tensile strength of the separate sheet (3) air-through nonwoven fabric alone (18.4 N / 25 mm).

[0063] Here, the maximum tensile force per unit width (25 mm) of each sheet is the tensile force per unit width at which each sheet begins to break; that is, it is also the tensile force per unit width at which the recycled sheet in each of composite sheets A and B begins to break. Therefore, from the above test, it can be said that when the composite sheet (skin-side composite sheet Z1) is pulled in the fiber orientation direction of the recycled sheet (skin-side core wrap sheet 8), the tensile force per unit width at which the recycled sheet in the composite sheet begins to break is higher than the tensile force per unit width at which the separate sheet (surface sheet 4) begins to break when pulled in the fiber orientation direction. In other words, by joining the recycled sheet (skin-side core wrap sheet 8) and the separate sheet (surface sheet 4), the strength of the recycled sheet (skin-side core wrap sheet 8) becomes such that it will not break unless a force greater than the tensile force at which the separate sheet (surface sheet 4) begins to break by itself is applied. By using a recycled sheet having such strength in the diaper 1, the risk of the recycled sheet being damaged can be reduced even when used by a wearer for a long period of time.

[0064] The above results are the effect when a recycled sheet (skin side core wrap sheet 8) with a recycled pulp content of 15% by weight is used. Therefore, by making the recycled pulp content of the recycled sheet less than 15% by weight, the recycled sheet can maintain the above-mentioned strength, and by using such a recycled sheet in diaper 1, the risk of damage to the recycled sheet, skin side core wrap sheet 8, can be reduced even after long-term use.

[0065] The following can also be said about the strength of the recycled sheet (non-skin-side core wrap sheet 9) in the non-skin-side composite sheet Z2. In this embodiment, as described above, the separate sheet (top sheet 4) of the skin-side composite sheet Z1 is a liquid-permeable sheet member, and the separate sheet (back sheet 5) of the non-skin-side composite sheet Z2 is a liquid-impermeable sheet member. Therefore, when the non-skin-side composite sheet Z2 is pulled in the fiber orientation direction of the recycled sheet (non-skin-side core wrap sheet 9), the tensile force per unit width at which the recycled sheet in the non-skin-side composite sheet Z2 begins to break is higher than the tensile force per unit width at which the recycled sheet in the skin-side composite sheet Z1 begins to break when the skin-side composite sheet Z1 is pulled in the fiber orientation direction of the recycled sheet (skin-side core wrap sheet 8). In other words, the tensile force at which the recycled sheet in each composite sheet begins to break increases as the tensile force at which the joined separate sheet begins to break increases. Because the non-skin-side composite sheet Z2 is joined to a liquid-impermeable separate sheet (back sheet 5) such as a synthetic resin film, the recycled sheet of the non-skin-side composite sheet Z2 (non-skin-side core wrap sheet 9) has a higher tensile force at the start of tearing than the recycled sheet of the skin-side composite sheet Z1 (skin-side core wrap sheet 8). That is, the non-skin-side core wrap sheet 9 of the non-skin-side composite sheet Z2 is more resistant to tearing than the skin-side core wrap sheet 8 of the skin-side composite sheet Z1. Therefore, compared to when the tensile force per unit width at the start of tearing of the non-skin-side core wrap sheet 9 of the non-skin-side composite sheet Z2 is lower than the tensile force per unit width at the start of tearing of the skin-side core wrap sheet 8 of the skin-side composite sheet Z1, the leakage prevention effect can be further improved when the tensile force per unit width at the start of tearing of the non-skin-side core wrap sheet 9 of the non-skin-side composite sheet Z2 is higher than the tensile force per unit width at the start of tearing of the skin-side core wrap sheet 8 of the skin-side composite sheet Z1.

[0066] The recycled sheets (skin side and non-skin side core wrap sheets 8, 9) contain pulp fibers as liquid absorbent fibers as well as thermoplastic resins, such as polyethylene (PE) and polypropylene (PP).

[0067] In this embodiment, the skin-side core wrap sheet 8 and the top sheet 4 are joined to form the skin-side composite sheet Z1, but as a modified example of the diaper 1, it is also possible to place another sheet material such as an auxiliary sheet between the skin-side core wrap sheet 8 and the top sheet 4. However, since the composite sheet in this embodiment is formed by joining the recycled sheet (skin-side core wrap sheet 8) to a separate sheet that can prevent the contents of the absorbent core 3 from leaking out due to breakage, it is preferable that the separate sheet be the top sheet 4 rather than an auxiliary sheet or the like.

[0068] Furthermore, in the skin-side composite sheet Z1, the fiber orientation direction of the recycled sheet (skin-side core wrap sheet 8) and the fiber orientation direction of the separate sheet (top sheet 4) are the same direction, and the maximum elongation (maximum elongation rate) of the separate sheet (top sheet 4) in the fiber orientation direction (longitudinal direction) is lower than the maximum elongation in the direction perpendicular to the fiber orientation direction (width direction). The direction perpendicular to the fiber orientation direction also has low tensile strength, and is the direction in which the separate sheet (top sheet 4) is likely to stretch. If the fiber orientation direction of the recycled sheet is arranged in the direction in which such a separate sheet is likely to stretch, i.e., the width direction, there is a greater risk of the joined recycled sheet breaking when the separate sheet is pulled in the same direction (width direction). Therefore, compared to when the fiber orientation direction of the skin-side core wrap sheet 8 is aligned with the direction of the highest maximum elongation of the surface sheet 4, aligning the fiber orientation direction of the skin-side core wrap sheet 8 with the direction of the lower maximum elongation of the surface sheet 4, i.e., the direction that is less likely to stretch, makes the surface sheet 4 less likely to tear when force is applied to the skin-side composite sheet Z1, and as a result, makes the skin-side core wrap sheet 8 less likely to tear.

[0069] Furthermore, the separate sheets (in this embodiment, the top sheet 4 and the back sheet 5) themselves also have the following strength. The tensile force per unit width when the length of the separate sheet after stretching in the fiber orientation direction is 105% of the length of the separate sheet before stretching is higher than the tensile force per unit width when the recycled sheet starts to break when a single recycled sheet (skin-side core wrap sheet 8 or non-skin-side core wrap sheet 9) is pulled in the fiber orientation direction. That is, from the test results (FIG. 3) for measuring the tensile strength described above, the tensile force per unit width (25 mm) when the recycled sheet starts to break is 9.2 N / 25 mm. This means that when the polypropylene spunbond nonwoven fabric and the air-through nonwoven fabric, which correspond to the separate sheets, are pulled in the fiber orientation direction and the stretched length is 105% of the length before stretching, the tensile force per unit width is higher than 9.2 N / mm. In other words, the separate sheet (surface sheet 4 or back sheet 5) will not break even if stretched by 5%, and will not break before the recycled sheet alone (skin side core wrap sheet 8 or non-skin side core wrap sheet 9). By joining a separate sheet having such strength as a material to a recycled sheet, the strength of the recycled sheet in the skin side composite sheet Z1 and non-skin side composite sheet Z2 can be increased.

[0070] Figure 5 is a plan view showing the application area of ​​the adhesive that bonds the topsheet 4 and the skin-side core wrap sheet 8. In Figure 5, the topsheet 4 and the skin-side core wrap sheet 8 are seen through to show the adhesive application area 20 (the area with downward-slanting left lines in the center in the width direction). As shown in the figure, in the skin-side composite sheet Z1 composed of the topsheet 4 and the skin-side core wrap sheet 8, the skin-side core wrap sheet 8 and the topsheet 4 are bonded together by a planar application of hot melt adhesive. This allows the tensile strength of the skin-side core wrap sheet (recycled sheet) in the skin-side composite sheet Z1 to be increased at the start of breakage.

[0071] 5, the hot melt adhesive is applied in a planar manner in the application region 20. In the portion where the hot melt adhesive is applied in a planar manner (application region 20), i.e., the portion where the hot melt adhesive is applied without any gaps, the strength of the skin side core wrap sheet 8 (recycled sheet) can be further increased.

[0072] Fig. 6 is a plan view showing the application area of ​​the adhesive that bonds the non-skin side core wrap sheet 9 and the back sheet 5. Fig. 7 is a plan view of Fig. 6, further showing the adhesive that bonds the absorbent core 3 and the non-skin side core wrap sheet 9. Both Figs. 6 and 7 show the diaper 1 in an unfolded state in plan view, and for ease of explanation, the components are shown in a limited manner. Fig. 6 shows the application area of ​​the adhesive through the non-skin side core wrap sheet 9 and the back sheet 5. Fig. 7 also shows the application area of ​​the adhesive through the non-skin side core wrap sheet 9, the back sheet 5, and the absorbent core 3.

[0073] In this embodiment, as shown in FIG. 6 , in the non-skin side composite sheet Z2 composed of a non-skin side core wrap sheet 9 and a back sheet 5, the non-skin side core wrap sheet 9 (recycled sheet) and the back sheet 5 (separate sheet) are bonded together with a hot melt adhesive. Specifically, the non-skin side composite sheet Z2 has multiple bonded regions 25 where the non-skin side core wrap sheet 9 and the back sheet 5 are bonded together with the hot melt adhesive. In this embodiment, there are seven bonded regions 25 spaced apart in the width direction and arranged along the length direction, but the number is not limited to this. Examples of application patterns for the hot melt adhesive include, but are not limited to, an Ω pattern, a spiral pattern, and a solid application pattern in which the adhesive is applied to the application area without gaps. Note that when the bonded region 25 is formed by applying the hot melt adhesive in a circular application pattern, for example, the width of the bonded region 25 (n1, n2, etc. described below) refers to the diameter of the circle, not the width of the line that describes the circle. By bonding with a hot melt adhesive in this manner, the tensile strength at the start of breakage of the non-skin side core wrap sheet 9 (recycled sheet) in the non-skin side composite sheet Z2 can be further increased.

[0074] As shown in Figure 6, the non-skin side composite sheet Z2 has a non-bonded region 26 where the non-skin side core wrap sheet 9 and the back sheet 5 are not bonded with hot melt adhesive. Similarly, in the skin side composite sheet Z1, the region of the skin side core wrap sheet 8 shown in Figure 5 excluding the application region 20 is the non-bonded region. If the hot melt adhesive were applied to the entire overlapping area of ​​the non-skin side core wrap sheet 9 and the back sheet 5 without any gaps, for example, the non-skin side composite sheet Z2 might become stiff. However, by having the non-bonded region 26, softness can be maintained, achieving a balance between strength and stiffness.

[0075] As shown in FIG. 6 , let the widthwise lengths of the bonded regions 25 be n1, n2, . . . n7, and the widthwise lengths of the non-bonded regions 26 be S1, S2, . . . S8. In this embodiment, the sum of the widthwise lengths of the bonded regions 25 of the non-skin side composite sheet Z2 (n1 + n2 + n3 + n4 + n5 + n6 + n7) is longer than the sum of the widthwise lengths of the non-bonded regions 26 (S1 + S2 + S3 + S4 + S5 + S6 + S7 + S8). In other words, the non-skin side composite sheet Z2 has more regions that are fixed with hot melt adhesive. This increase in the number of bonded regions 25 improves the strength of the non-skin side composite sheet Z2, making the non-skin side core wrap sheet 9 (recycled sheet) in the non-skin side composite sheet Z2 less likely to tear.

[0076] Furthermore, the length L1 over which the hot melt adhesive is continuously applied in the longitudinal direction of the non-skin side composite sheet Z2 (i.e., the longitudinal length of the bonding region 25) is longer than the length over which the hot melt adhesive is continuously applied in the width direction (any of n1 to n7). The non-skin side core wrap sheet 9 (recycled sheet) has a higher tensile strength in the longitudinal direction, which is the fiber orientation direction, than in the width direction, and by having a long continuous layer of hot melt adhesive in the longitudinal direction, which is the fiber orientation direction, the non-skin side core wrap sheet 9 can be made more resistant to tearing.

[0077] 5, the bonding region (application region 20) where the skin side core wrap sheet 8 and the top sheet 4 are bonded with the hot melt adhesive is provided over the entire longitudinal area of ​​the skin side core wrap sheet 8. Similarly, as shown in FIG. 6, the bonding region 25 where the non-skin side core wrap sheet 9 and the back sheet 5 are bonded with the hot melt adhesive is provided over the entire longitudinal area of ​​each non-skin side core wrap sheet 9. It is sufficient that at least a portion of the bonding region 25 is provided over the entire longitudinal area of ​​the recycled sheet. In the longitudinal direction where tensile strength is high, having the bonding regions (20, 25) of the hot melt adhesive over the entire longitudinal area of ​​the recycled sheet (skin side core wrap sheet 8, non-skin side core wrap sheet 9) makes the recycled sheet more resistant to tearing.

[0078] In this embodiment, as described above, the skin-side core wrap sheet 8, which is a recycled sheet of the skin-side composite sheet Z1 arranged on the skin side of the absorbent core 3 in the thickness direction, is arranged adjacent to the skin side of the absorbent core 3. Furthermore, the non-skin-side core wrap sheet 9, which is a recycled sheet of the non-skin-side composite sheet Z2 arranged on the non-skin side of the absorbent core 3 in the thickness direction, is arranged adjacent to the non-skin side of the absorbent core 3. Since the absorbent core 3 swells when it absorbs liquid, if a core wrap sheet is provided to wrap around the absorbent core 3, the swelling of the absorbent core 3 applies force to the core wrap sheet, which may tear the core wrap sheet at the side portion wrapping the absorbent core 3. In this embodiment, the core wrap sheets (skin-side core wrap sheet 8, non-skin-side core wrap sheet 9) are arranged separately on the skin side and non-skin side of the absorbent core 3, respectively, thereby reducing the load on the core wrap sheet and the risk of tearing.

[0079] As shown in Figure 7, the absorbent core 3 and the non-skin side core wrap sheet 9 have a core bonding region 27 where they are bonded to each other with a hot melt adhesive. In this embodiment, three core bonding regions 27 are provided along the longitudinal direction and spaced apart in the width direction, but the number is not limited to this. The non-bonded region 26, where the non-skin side core wrap sheet 9 and the backsheet 5 are not bonded with the hot melt adhesive, has a portion that overlaps with the core bonding region 27 in a plan view. The non-bonded region 26, where the hot melt adhesive is not applied, may have reduced strength, but by having a portion that overlaps with the core bonding region 27, it is possible to prevent a decrease in strength of the recycled sheet (non-skin side core wrap sheet 9) of the non-skin side composite sheet Z2.

[0080] === Second Embodiment === As an example of an absorbent article according to the second embodiment, an absorbent pad 2 that absorbs excrement such as urine and feces will be described.

[0081] <Basic structure of absorbent pad 2> Fig. 8 is a schematic plan view of an absorbent pad 2 as an absorbent article according to a second embodiment in an unfolded and stretched state, viewed from the skin side. Fig. 9 is an exploded perspective view of a main part of the absorbent pad 2 shown in Fig. 8. Fig. 10 is a cross-sectional view taken along line BB shown in Fig. 8.

[0082] As shown in Fig. 8, the absorbent pad 2 has a longitudinal direction, a width direction, and a thickness direction (not shown), similar to the first embodiment. Furthermore, as shown in Fig. 10, the direction in which the components constituting the absorbent pad 2 are stacked is referred to as the thickness direction. In the thickness direction, the side in contact with the wearer is referred to as the skin side, and the opposite side is referred to as the non-skin side. The definitions of the unfolded and stretched states of the absorbent pad 2 are the same as those in the first embodiment.

[0083] As shown in Figures 8 and 9, the absorbent pad 2 comprises a top sheet 34, a back sheet 35, an absorbent body 33, an exterior sheet 36, and a pair of side sheets 37. The top sheet 34 is a liquid-permeable sheet provided closer to the skin than the absorbent body 33 in the thickness direction, and examples of such a sheet include an air-through nonwoven fabric and a spunbond nonwoven fabric. The back sheet 35 is a liquid-impermeable sheet provided closer to the skin than the absorbent body 33 in the thickness direction, and examples of such a sheet include a synthetic resin film and a hydrophobic SMS nonwoven fabric. The top sheet 34 and the back sheet 35 contain a thermoplastic resin (such as polyethylene (PE) or polypropylene (PP)).

[0084] The pair of side sheets 37 are sheets (e.g., nonwoven fabric) that extend outward in the width direction from both widthwise edges on the skin-facing side of the top sheet 34. The exterior sheet 36 is a liquid-impermeable sheet that is located closer to the skin than the back sheet 5 in the thickness direction, and forms the outer shape of the absorbent pad 2, i.e., a shape in which the longitudinal center is narrowed inward in the width direction.

[0085] The absorbent body 33 is a member having liquid absorption and liquid retention properties and is located between the topsheet 34 and the backsheet 35 in the thickness direction. In the second embodiment, the absorbent body 33 includes a first absorbent core 33a located on the skin side and a second absorbent core 33b located on the non-skin side of the first absorbent core 33a. The first absorbent core 33a and the second absorbent core 33b can be, for example, liquid-absorbent fibers such as pulp containing SAP (super absorbent polymer) molded into a predetermined shape. In this embodiment, the first absorbent core 33a has a generally gourd-like or hourglass-like shape that is long in the longitudinal direction and has a narrowed portion near the center of the longitudinal direction that extends inward in the width direction. On the other hand, the second absorbent core 33b has a generally rectangular shape that is long in the longitudinal direction and narrow in the width direction in a plan view. The second absorbent core 33b has a longitudinal dimension shorter than that of the first absorbent core 33a and a width dimension shorter than that of the first absorbent core 33a. Therefore, both longitudinal and widthwise end edges of the first absorbent core 33a are located outside both longitudinal and widthwise end edges of the second absorbent core 33b. There are no particular restrictions on the shape of the absorber 33.

[0086] In the second embodiment, a first core wrap sheet 38 is provided on the skin side of the first absorbent core 33a, and a second core wrap sheet 39 is provided to wrap the second absorbent core 33b from the non-skin side. In the second embodiment, the first core wrap sheet 38 is arranged so as not to wrap the first absorbent core 33a. The first and second core wrap sheets 38, 39 contain a thermoplastic resin in addition to pulp fibers as liquid-absorbent fibers. Examples of thermoplastic resins include polyethylene (PE) and polypropylene (PP). Details of the first and second core wrap sheets 38, 39 will be described later.

[0087] The absorbent pad 2 also has leakage preventing walls 48. The leakage preventing walls 48 are configured to be able to stand up on the skin-facing side of the wearer, and are provided in a pair on the left and right. As shown in Fig. 10, the leakage preventing walls 48 are formed by folding the inner side portions in the width direction of the side sheets 37 back toward the skin side, and providing the folded-back portions with leakage preventing wall elastic members 60 that stretch in the longitudinal direction. The leakage preventing walls 48 can suppress lateral leakage of excrement. Note that in Fig. 8, thread-like leakage preventing wall elastic members 60 are arranged on each side with a gap in the width direction, but the number of these is not particularly limited.

[0088] In this embodiment, the first absorbent core 33a of the absorbent body 33 has a slit 45a recessed in the thickness direction from the skin side to the non-skin side, preferably a through slit 45a. The slit 45a is located closer to the ventral side than the longitudinal center of the absorbent pad 2, and extends longitudinally through the center of the width of the absorbent body 33. The second absorbent core 33b has a slit 45b recessed in the thickness direction from the skin side to the non-skin side, preferably a through slit 45b. The slit 45b is located closer to the ventral side than the longitudinal center of the absorbent pad 2, and extends longitudinally through the center of the width of the absorbent body 33. The slits 45a and 45b are formed to at least partially overlap in a plan view. This allows excreted urine that reaches the second absorbent core 33b through the slit 45a of the first absorbent core 33a to be drawn further into the second absorbent core 33b via the slit 45b. The longitudinal dimensions (length) and width dimensions (width) of the slits 45a, 45b in a plan view are appropriately adjusted in consideration of the sizes of the first absorbent core 33a and the second absorbent core 33b. The width and length of the slits 45a, 45b are, for example, 5.0 to 50 mm and 50 to 300 mm.

[0089] In this embodiment, the absorbent body 33 includes a pair of compressed portions 46. The pair of compressed portions 46 extend longitudinally on both widthwise outer sides of the slit 45a. The pair of compressed portions 46 are formed by compressing the first absorbent core 33a and the second absorbent core 33b in the thickness direction, starting from the skin-facing surface of the first absorbent core 33a. However, the pair of compressed portions 46 may also be formed by compressing both the topsheet 34 and the absorbent body 33. Each of the pair of compressed portions 46 is formed linearly in a plan view, but the shape is not particularly limited. The pair of compressed portions 46 prevents urine from moving outward on the topsheet 34 and leaking to the outside, and makes it easier to draw urine into the absorbent body 33.

[0090] (Recycled sheet, separate sheet and composite sheet in the second embodiment) Similar to the first embodiment, the first core wrap sheet 38 and the second core wrap sheet 39 in the second embodiment are recycled sheets containing 15% by weight or more of recycled pulp recycled from used disposable absorbent articles (e.g., used disposable diapers and absorbent pads) (hereinafter, the first core wrap sheet 38 will also be referred to as the first recycled sheet, and the second core wrap sheet 39 will also be referred to as the second recycled sheet). The absorbent pad 2 has a composite sheet formed by joining the first recycled sheet to a separate sheet adjacent to the first recycled sheet in the thickness direction of the absorbent pad 2. Specifically, the separate sheet opposite the first core wrap sheet 38 (first recycled sheet) is the top sheet 34, and the first core wrap sheet 38 and the top sheet 34 are joined to form a first composite sheet Z3 (see FIG. 10). The absorbent pad 2 also has a composite sheet formed by joining the second recycled sheet to a separate sheet adjacent to the second recycled sheet in the thickness direction of the absorbent pad 2. Specifically, the separate sheet from the second core wrap sheet 39 (second recycled sheet) is the back sheet 35, and the non-skin side of the second core wrap sheet 39 is joined to the back sheet 35 to form the second composite sheet Z4 (see FIG. 10). Therefore, the absorbent pad 2 has a first composite sheet Z3, which is a composite sheet arranged on the skin side in the thickness direction of the first absorbent core 33a, and a second composite sheet Z4, which is a composite sheet arranged on the non-skin side in the thickness direction of the second absorbent core 33b.

[0091] The effects of the first composite sheet Z3 are similar to those of the skin-side composite sheet Z1 of the first embodiment, and the effects of the second composite sheet Z4 are similar to those of the non-skin-side composite sheet Z2 of the first embodiment. Therefore, in the following explanation, differences will be described in detail, and explanations of common functions and effects will be omitted.

[0092] In this embodiment, the mass ratio of the superabsorbent polymer contained in the first absorbent core 33a is greater than the mass ratio of the superabsorbent polymer contained in the second absorbent core 33b. Here, the mass ratio of the superabsorbent polymer in each absorbent core refers to the ratio of the mass of the superabsorbent polymer to the total mass of each absorbent core (i.e., the mass of the fiber aggregate + the mass of the superabsorbent polymer). Therefore, when absorbing excrement, the first absorbent core 33a is more likely to expand than the second absorbent core 33b. The first core wrap sheet 38 (first recycled sheet) of the first absorbent core 33a is arranged so as not to wrap around the first absorbent core 33a, while the second core wrap sheet 39 (second recycled sheet) of the second absorbent core 33b is arranged so as to wrap around the second absorbent core 33b. By forming the first core wrap sheet 38 of the first absorbent core 33a, which has a large amount of superabsorbent polymer (SAP), so that it does not wrap around the first absorbent core 33a, the burden on the first core wrap sheet 38 of the first absorbent core 33a, which has a large amount of superabsorbent polymer and is more likely to expand, is reduced, and the risk of the first core wrap sheet 38 tearing is reduced.

[0093] In this embodiment, the first absorbent core 33a is positioned on the skin side and the second absorbent core 33b is positioned on the non-skin side of the first absorbent core 33a, but this is not limiting, and the first absorbent core 33a may be positioned on the non-skin side and the second absorbent core 33b on the skin side of the first absorbent core 33a. In other words, the absorbent pad 2 may be configured so that an absorbent core with a high mass ratio of superabsorbent polymer is provided on the non-skin side.

[0094] Furthermore, as described above, if the surface sheet 34 (separate sheet) and the first core wrap sheet 38 contain a thermoplastic resin, for example, by forming compressed portions such as the pair of compressed portions 46 described above on the skin side of the surface sheet 34, the thermoplastic resin of the surface sheet 34 and the thermoplastic resin of the first core wrap sheet 38 are thermally fused together, making it possible to more firmly bond the surface sheet 34 (separate sheet) and the first core wrap sheet 38 (first recycled sheet). This therefore increases the strength of the recycled sheet in the first composite sheet Z3.

[0095] When the surface sheet 34 (separate sheet) and the first core wrap sheet 38 (first recycled sheet) are heat-sealed, it is desirable that the thermoplastic resin of the first recycled sheet and the thermoplastic resin of the separate sheet are the same type of thermoplastic resin. Heat-sealing the same type of thermoplastic resin can increase the strength of the first core wrap sheet 38 (first recycled sheet) in the first composite sheet Z3.

[0096] 11 is a plan view showing the second absorbent core 33b and the second core wrap sheet 39 of the absorbent pad 2 in an unfolded state. For convenience, only the second absorbent core 33b and the second core wrap sheet 39 are shown to show the overlapping of the second core wrap sheet 39. As shown in Figure 11, at least a portion of the second core wrap sheet 39 (second recycled sheet) has an overlapping region VP where the second core wrap sheets 39 overlap each other in a plan view. In the overlapping region VP, the second core wrap sheets 39 are heat-sealed together. Since the second core wrap sheet 39 contains a thermoplastic resin, the second core wrap sheets 39 are heat-sealed together, which increases the strength of the second core wrap sheet 39 (second recycled sheet), further reducing the risk of tearing.

[0097] ===Other=== The above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention includes equivalents thereof.

[0098] In the first and second embodiments described above, the skin-side core wrap sheet 8, the non-skin-side core wrap sheet 9, the first core wrap sheet 38, and the second core wrap sheet 39 contain recycled pulp made from disposable absorbent articles, but this is not limited to this. For example, the absorbent core 3, the first absorbent core 33a, and the second absorbent core 33b may contain recycled pulp, or another sheet material constituting the absorbent article may contain recycled pulp. [Explanation of symbols]

[0099] 1 Diaper (absorbent article) (first embodiment) 1A Ventral waist 1B Inseam 1C Back waist 2 Absorbent pad (absorbent article) (second embodiment) 3 absorbent core 4 Surface sheet (separate sheet) 5 Back sheet (separate sheet) 6 Exterior sheet 7 Side seats 8 Skin side core wrap sheet (recycled sheet) 9 Non-skin side core wrap sheet (recycled sheet) 10 Flap section 11 Base sheet 12 First fastening member 13 Second fastening member 14 Target section 16 Elastic member around the legs 17 Inner leak-proof gathers 18 Outer leak-proof gathers 20 Application area 21 waist elastic member 22 Waist Gather 25 Joint area 26 Non-bonded area 27 Core junction area 33 Absorbent 33a First absorbent core 33b Second absorbent core 34 Surface sheet (separate sheet) 35 Back sheet (separate sheet) 36 Exterior sheet 37 Side seat 38 First core wrap sheet (first recycled sheet) 39 Second core wrap sheet (second recycled sheet) 45a slit 45b slit 46 Pair of compression parts 48 Leakage prevention wall 60 Leak-proof wall elastic member 171 Inner leak-proof elastic member 181 Outer leak-proof elastic member Z1 Skin-side composite sheet (composite sheet) Z2 Non-skin side composite sheet (composite sheet) Z3 No. 1 composite sheet (composite sheet) Z4 2nd composite sheet (composite sheet)

Claims

1. An absorbent article comprising a recycled sheet containing recycled pulp obtained by recycling disposable absorbent articles, a composite sheet formed by joining a separate sheet adjacent to the recycled sheet in the thickness direction of the absorbent article and the recycled sheet; The recycled pulp content in the recycled sheet is less than 15% by weight, When the composite sheet is pulled in the fiber orientation direction of the recycled sheet, the tensile force per unit width at which the recycled sheet in the composite sheet starts to break is higher than the tensile force per unit width at which the separate sheet starts to break when the separate sheet is pulled alone in the fiber orientation direction, The recycled sheet and the separate sheet in the composite sheet are joined together by a hot melt adhesive, The sheet does not include a heat embossing unit for joining the recycled sheet and the separate sheet to each other. An absorbent article characterized by:

2. The absorbent article according to claim 1, In the composite sheet, the orientation direction of the fibers of the recycled sheet and the orientation direction of the fibers of the separate sheet are the same direction, The maximum elongation of the separate sheet in the fiber orientation direction is lower than the maximum elongation in the direction perpendicular to the fiber orientation direction. An absorbent article characterized by:

3. The absorbent article according to claim 1 or 2, In the orientation direction of the fibers, the tensile force per unit width when the length of the separate sheet after stretching becomes 105% of the length of the separate sheet before stretching is higher than the tensile force per unit width when the recycled sheet starts to break when the recycled sheet is pulled alone in the orientation direction of the fibers. An absorbent article characterized by:

4. The absorbent article according to any one of claims 1 to 3, The recycled sheet contains a thermoplastic resin. An absorbent article characterized by:

5. The absorbent article according to claim 4, the separate sheet contains a thermoplastic resin, An absorbent article characterized by:

6. The absorbent article according to claim 5, The thermoplastic resin of the recycled sheet and the thermoplastic resin of the separate sheet are the same type of thermoplastic resin. An absorbent article characterized by:

7. The absorbent article according to any one of claims 1 to 6, The hot melt adhesive is applied in a planar manner at least in part. An absorbent article characterized by:

8. The absorbent article according to any one of claims 1 to 6, The composite sheet has a non-bonded region where the recycled sheet and the separate sheet are not bonded by the hot melt adhesive. An absorbent article characterized by:

9. The absorbent article according to claim 8, In the expanded state, the orientation direction of the fibers is the longitudinal direction of the absorbent article, and the direction perpendicular to the longitudinal direction is the width direction, When the region of the composite sheet where the recycled sheet and the separate sheet are joined by the hot melt adhesive is defined as a joining region, The total length of the bonded regions in the width direction is greater than the total length of the non-bonded regions in the width direction. An absorbent article characterized by:

10. 10. The absorbent article according to any one of claims 1 to 9, In the developed state, the orientation direction of the fibers is the longitudinal direction of the absorbent article, and the direction perpendicular to the longitudinal direction is the width direction. The length of the continuous hot melt adhesive in the composite sheet is longer in the longitudinal direction than in the width direction. An absorbent article characterized by:

11. 8. The absorbent article according to any one of claims 1 to 7, At least a part of the bonding area where the recycled sheet and the separate sheet are bonded by the hot melt adhesive is provided over the entire area in the longitudinal direction of the recycled sheet. An absorbent article characterized by:

12. The absorbent article according to any one of claims 1 to 11, having an absorbent core, a skin-side composite sheet, which is the composite sheet arranged on the skin side in the thickness direction of the absorbent core; and a non-skin-side composite sheet, which is the composite sheet arranged on the non-skin side in the thickness direction of the absorbent core, the recycled sheet of the skin side composite sheet is a skin side core wrap sheet disposed adjacent to the skin side of the absorbent core, The recycled sheet of the non-skin side composite sheet is a non-skin side core wrap sheet arranged adjacent to the non-skin side of the absorbent core. An absorbent article characterized by:

13. 13. The absorbent article of claim 12, the separate sheet of the skin side composite sheet is a liquid-permeable sheet member, the separate sheet of the non-skin side composite sheet is a liquid-impermeable sheet member, When the non-skin side composite sheet is pulled in the fiber orientation direction of the recycled sheet, the tensile force per unit width at which the non-skin side composite sheet starts to break is higher than the tensile force per unit width at which the skin side composite sheet starts to break when the skin side composite sheet is pulled in the fiber orientation direction of the recycled sheet. An absorbent article characterized by:

14. The absorbent article according to claim 12 or 13, the separate sheet of the non-skin side composite sheet is disposed adjacent to the non-skin side of the non-skin side core wrap sheet, the non-skin side composite sheet has a non-bonded region where the non-skin side core wrap sheet and the separate sheet are not bonded by a hot melt adhesive; the absorbent core and the non-skin side core wrap sheet have a core joining region where they are joined to each other by the hot melt adhesive; In a plan view of the absorbent article in an unfolded state, the non-bonded region has a portion overlapping with the core bonded region. An absorbent article characterized by:

15. The absorbent article according to any one of claims 1 to 11, a first absorbent core comprising at least a superabsorbent polymer; a second absorbent core comprising at least a superabsorbent polymer; and the mass ratio of the superabsorbent polymer contained in the first absorbent core is greater than the mass ratio of the superabsorbent polymer contained in the second absorbent core; a first recycled sheet, which is the recycled sheet, is provided as a core wrap sheet arranged so as not to wrap the first absorbent core; The second recycled sheet is provided as a core wrap sheet arranged to wrap the second absorbent core. An absorbent article characterized by:

16. 16. The absorbent article of claim 15, The recycled sheet contains a thermoplastic resin, At least a portion of the second recycled sheet has an overlapping region where the recycled sheets overlap each other in a plan view of the absorbent article in an unfolded state, The recycled sheets are heat-sealed to each other in the overlapping region. An absorbent article characterized by:

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