Laminate and absorbent article comprising said laminate

Abstract

The purpose of the present disclosure is to provide a nonwoven fabric which, when used in an absorbent article, has elasticity and feels soft to the touch. A laminate according to the present disclosure has the following configuration.　A laminate (10) for an absorbent article comprises a first sheet (11), a second sheet (12), and an elastic member (8) disposed between the first sheet (11) and the second sheet (12) and extending in an extension direction (D) which does not cross the thickness direction in the first sheet (11) or the second sheet (12). The laminate (10) comprises plurality of fixing parts (15) which fix the elastic member (8) to the first sheet (11) and the second sheet (12) along the extension direction (D). The first sheet (11) and the second sheet (12) have a first sheet inner surface (11a) and a second sheet inner surface (12a), respectively, which are surfaces in contact with the elastic member (8). At least one of the first sheet inner surface (11a) and the second sheet inner surface (12a) includes thermoplastic fibers (20) having a plurality of protrusions (21), and each of the plurality of protrusions (21) includes an inorganic particle.

Description

Laminate and absorbent article including said laminate

[0001] The present invention relates to a laminate and an absorbent article comprising the laminate.

[0002] Laminates for absorbent articles having elastic members between a pair of sheets are known. For example, Patent Document 1 discloses a stretchable sheet for absorbent articles in which a pair of sheets are joined by a plurality of joints and a plurality of elastic members stretchable in the left-right direction are arranged at intervals in the up-down direction between the pair of sheets, the stretchable sheet having a group of joints including at least one pair of joints that sandwich the elastic members without using adhesive. Furthermore, laminates in which elastic members are fixed between a pair of sheets by a number of methods are known, such as a laminate for absorbent articles in which elastic members are joined to the pair of sheets using adhesive.

[0003] Patent No. 7305861

[0004] However, in the stretchable sheet of Patent Document 1, when forming the joints, the elastic member may be cut by heat or pressure and come off from the joints. On the other hand, if the temperature, pressure, or energy used when forming the joints is reduced to prevent the elastic member from being cut, the elastic member may no longer be fixed to the joints, causing the elastic member to shift, which may result in uneven wrinkles in the elastic member and a poor appearance. In addition, if the elastic member is bonded to the sheet with an adhesive or the like, the adhesive may peel off from the sheet, causing the elastic member to shift.

[0005] An object of the present invention is to provide a laminate for absorbent articles that can suppress slippage of elastic members when used in absorbent articles, and an absorbent article including the laminate.

[0006] One aspect of the present invention is a laminate for absorbent articles comprising a first sheet, a second sheet, and an elastic member disposed between the first and second sheets and stretched in an extension direction that does not intersect with the thickness direction of the first and second sheets, the laminate comprising a plurality of fixing portions that fix the elastic member to the first and second sheets along the extension direction, the first and second sheets having a first sheet inner surface and a second sheet inner surface, respectively, that are surfaces that contact the elastic member, at least one of the first sheet inner surface and the second sheet inner surface comprising thermoplastic fibers having a plurality of protrusions, each of the plurality of protrusions comprising inorganic particles.

[0007] According to the present invention, it is possible to provide a laminate that can suppress slippage of elastic members when used in an absorbent article, and an absorbent article including the laminate.

[0008] FIG. 1 is a schematic diagram showing an example of the configuration of an absorbent article using a laminate according to an embodiment. FIG. 2 is a plan view of the absorbent article of FIG. 1 unfolded. FIG. 3 is an external view of a portion of a laminate according to a first embodiment. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view taken along line V-V in FIG. 3. FIG. 6 is an SEM photograph of the outer surface of a laminate according to a first embodiment. FIG. 7 is an SEM photograph of thermoplastic fibers constituting a laminate according to a first embodiment. FIG. 8 is an SEM photograph of conventional fibers. FIG. 9 is a cross-sectional view showing the second sheet of FIG. 5. FIG. 10 is a cross-sectional view showing the first sheet of FIG. 5. FIG. 11 is a cross-sectional view of a laminate having the second sheet of FIG. 9 and the first sheet of FIG. 10. FIG. 12 is an external view of a portion of a laminate according to a second embodiment. FIG. 13 is a cross-sectional view of a laminate according to a third embodiment, corresponding to the cross-sectional view of FIG. 5.

[0009] The present embodiment relates to the following aspects: [Aspect 1] A laminate for an absorbent article comprising a first sheet, a second sheet, and elastic members disposed between the first sheet and the second sheet and stretched in an extension direction that does not intersect with a thickness direction of the first sheet and the second sheet, the laminate comprising a plurality of fixing parts that fix the elastic members to the first sheet and the second sheet along the extension direction, the first sheet and the second sheet having a first sheet inner surface and a second sheet inner surface that are surfaces that come into contact with the elastic members, respectively, at least one of the first sheet inner surface and the second sheet inner surface contains thermoplastic fibers having a plurality of protrusions, and each of the plurality of protrusions contains inorganic particles.

[0010] In the laminate, when the fixing portion is, for example, a bonded portion using an adhesive, the anchor effect of the adhesive or the like due to the convex portions of the thermoplastic fiber increases the bonding strength of the bonded portion and makes the elastic member less likely to peel off when the elastic member is directly fixed by the bonded portion. This makes it possible to prevent the elastic member from slipping. Furthermore, even if the bonded portion peels off, the convex portions come into contact with the elastic member, increasing frictional resistance, thereby preventing the elastic member from slipping off in the laminate.

[0011] In the above-mentioned laminate, when the fixing portion is, for example, a heat-sealed portion formed by heat fusion, the first sheet and the second sheet are joined to each other in the indirect fixing of the elastic member by the heat-sealed portion, so that the inner surfaces of the first sheet and the second sheet come into contact with the elastic member, respectively, and the elastic member is gripped in the thickness direction.

[0012] Furthermore, in the regions where the inner surface of the first sheet and the inner surface of the second sheet contact the elastic member, the plurality of protrusions in the regions that are not in the adhesive portion come into contact with the elastic member, increasing the frictional resistance of the elastic member, making it easier for the laminate to fix the elastic member, and the laminate can suppress slippage of the elastic member. Furthermore, by containing inorganic particles in each of the plurality of protrusions, the protrusions can be formed stably.

[0013] When rubber such as rubber threads or rubber bands is used as the elastic member, the laminate fixes the elastic member, making it difficult for the rubber to "slip away" from its original position.

[0014] [Aspect 2] The laminate according to Aspect 1, wherein the plurality of fixing portions include at least one of a plurality of heat-sealed portions and a plurality of adhesive portions, the plurality of heat-sealed portions join the first sheet and the second sheet to each other by heat fusion and indirectly fix the elastic member, and the plurality of adhesive portions directly fix the elastic member to the inner surface of the first sheet and the inner surface of the second sheet.

[0015] The fixing portions of the laminate are at least one of a plurality of heat-sealed portions and a plurality of adhesive portions, and the laminate can achieve the same effects as in aspect 1.

[0016] [Aspect 3] The laminate according to aspect 2, wherein both the inner surface of the first sheet and the inner surface of the second sheet include the thermoplastic fiber having the plurality of protrusions.

[0017] The laminate includes protrusions containing inorganic particles on both the inner surface of the first sheet and the inner surface of the second sheet, which can further increase the frictional resistance generated in the elastic member and the bonding strength between the elastic member and the adhesive, compared to when multiple protrusions are provided on either the inner surface of the first sheet or the inner surface of the second sheet alone, thereby further suppressing slippage of the elastic member.

[0018] [Aspect 4] The laminate according to Aspect 2 or 3, wherein the first sheet and the second sheet have a first sheet outer surface and a second sheet outer surface, respectively, which are surfaces opposite to the surface in contact with the elastic member, and when the first sheet inner surface contains the thermoplastic fibers having the plurality of protrusions, the mass proportion of the inorganic particles on the first sheet inner surface is higher than the mass proportion of the inorganic particles on the first sheet outer surface, and when the second sheet inner surface contains the thermoplastic fibers having the plurality of protrusions, the mass proportion of the inorganic particles on the second sheet inner surface is higher than the mass proportion of the inorganic particles on the second sheet outer surface.

[0019] In the laminate, the outer surfaces of the first and second sheets, which contain fewer inorganic particles, have a lower fineness (Dtex: fiber weight per 10,000 m) than the inner surfaces of the first and second sheets, which contain more inorganic particles. The fiber length is increased by the amount of inorganic particles removed, which increases the amount of fiber used for heat fusion and strengthens the bond strength of the heat-sealed portion. The increased bond strength makes it difficult for the first and second sheets to peel, allowing the elastic member to be more firmly fixed, thereby preventing the elastic member from slipping.

[0020] [Aspect 5] The laminate according to Aspect 4, wherein at least one of the first sheet and the second sheet contains small-diameter thermoplastic fibers having a smaller fiber diameter than the thermoplastic fibers and not containing the inorganic particles, and when the first sheet contains the small-diameter thermoplastic fibers, the first sheet has a first-sheet intermediate layer between the inner surface of the first sheet and the outer surface of the first sheet, the first-sheet intermediate layer containing the small-diameter thermoplastic fibers, and when the second sheet contains the small-diameter thermoplastic fibers, the second sheet has a second-sheet intermediate layer between the inner surface of the second sheet and the outer surface of the second sheet, the second-sheet intermediate layer containing the small-diameter thermoplastic fibers.

[0021] The laminate has at least one of a first sheet intermediate layer and a second sheet intermediate layer containing small-diameter thermoplastic fibers, and the small-diameter thermoplastic fibers do not contain inorganic particles. Therefore, the fiber length is increased even more than in the effect of aspect 4, and the bonding strength of the heat-sealed portion is increased, thereby suppressing slippage of the elastic member.

[0022] [Aspect 6] The laminate according to any one of aspects 2 to 5, wherein the mass ratio of the inorganic particles in the thermoplastic fibers in at least one of the first sheet and the second sheet is 4.5% or more and 21.0% or less.

[0023] The laminate contains inorganic particles at a mass ratio of not more than the upper limit, thereby preventing the inorganic particles from falling off from the thermoplastic fibers, and the laminate contains inorganic particles at a mass ratio of not less than the lower limit, thereby improving the heat-sealing properties of the heat-sealed portions and the anchoring effect of the adhesive portions. Furthermore, the improved heat-sealing properties reduce the temperature and pressure required for heat-sealing in forming the laminate, thereby preventing breakage of the elastic member.

[0024] [Aspect 7] The laminate according to any one of Aspects 2 to 6, wherein the thermal conductivity at 160°C of at least one of the first sheet and the second sheet is 0.191 W / (m·k) or more and 0.224 W / (m·k) or less.

[0025] In the laminate, the thermal conductivity of the first sheet having inorganic particles and the second sheet is improved, so that the area of ​​the heat-sealed portion is increased, and the heat-sealing property can be further improved.

[0026] [Aspect 8] The laminate according to any one of Aspects 2 to 7, wherein the plurality of fixing portions include only the plurality of heat-sealed portions.

[0027] The laminate does not use adhesive in the fixing parts, but only uses heat-sealed parts, so that flexibility and stretchability are improved and petroleum-derived materials can be reduced.

[0028] [Aspect 9] The laminate according to Aspect 8, wherein the plurality of heat-sealed portions include a plurality of pairs of opposing heat-sealed portions arranged opposite each other in a direction perpendicular to the stretching direction, the plurality of pairs of opposing heat-sealed portions are aligned at intervals in the stretching direction, and the pair of opposing heat-sealed portions grips the elastic member.

[0029] In the laminate, the elastic member is directly fixed by sandwiching it between a pair of opposed heat-sealed portions, and therefore, displacement of the elastic member can be further suppressed.

[0030] [Aspect 10] An absorbent article comprising the laminate according to any one of Aspects 1 to 9. The absorbent article provides the same effects as Aspect 1.

[0031] [Aspect 11] The absorbent article according to aspect 10, wherein the plurality of fixed parts include only a plurality of heat-sealed parts. The absorbent article can achieve the same effects as in aspect 8.

[0032] Hereinafter, a laminate for an absorbent article according to an embodiment and an absorbent article using the same will be described using a pants-type disposable diaper (hereinafter simply referred to as a "disposable diaper") as an example. However, the present invention is not limited to the embodiment and example, and can be applied to various absorbent articles within the scope of the present invention. Examples of absorbent articles include so-called three-piece and two-piece disposable diapers, tape-type diapers, sanitary shorts-type napkins, and pet diapers.

[0033] [First embodiment] Figures 1 to 4 are diagrams illustrating a laminate for an absorbent article according to this embodiment. Figure 1 is a schematic diagram showing an example of the configuration of a disposable diaper 1, which is an absorbent article. Figure 2 is a plan view showing the example of the configuration of the disposable diaper 1, which is an absorbent article, in an unfolded state, showing the elastic members 8, 8a, and 8b in a stretched state. Figure 3 is an external view of a portion of a laminate 10 in which the elastic member 8 is fixed using thermal fusion.

[0034] In the configuration example shown in FIG. 1 , the disposable diaper 1 includes a ventral section 3, a dorsal section 2, and an intermediate section 4 between the ventral section 3 and the dorsal section 2. The ventral section 3 is a section of the disposable diaper 1 that covers the ventral side of the wearer. The intermediate section 4 is a section of the disposable diaper 1 that covers the crotch area of ​​the wearer. The dorsal section 2 is a section of the disposable diaper 1 that covers the dorsal side of the wearer. The intermediate section 4 includes a pair of leg gather sections 5 having elastic members 8a, and an absorbent main body 6. The absorbent main body 6 includes a pair of leakage barrier walls 7 having elastic members 8b. The end portions of the absorbent main body 6 and the pair of leg gather sections 5 on the ventral section 3 side extend to the ventral section 3, and the end portions on the dorsal section 2 side extend to the dorsal section 3.

[0035] The disposable diaper 1 is formed by joining together a pair of ventral joints located at both ends of the ventral portion 3 in the waistline direction and a pair of dorsal joints located at both ends of the dorsal portion 2 in the waistline direction. The pair of ventral joints and the pair of dorsal joints joined together are referred to as a pair of side joints SC. In this case, in the disposable diaper 1, the ventral portion 3 and the dorsal portion 2 joined together by the pair of side joints SC form a waist portion WP that covers the waist of the wearer. Furthermore, a waist opening WH through which the wearer's waist passes is defined by the ends of the ventral portion 3 and the dorsal portion 2 opposite to the intermediate portion 4. Furthermore, in the disposable diaper 1, a pair of leg openings LH through which the wearer's legs pass is defined by the side portions on both sides of the intermediate portion 4.

[0036] The disposable diaper 1 includes a plurality of elastic members 8 for waist gathering in each of the back-side portion 2 and the abdominal-side portion 3. In the back-side portion 2, the plurality of elastic members 8 each extend from one end to the other end in the waist direction and are arranged at intervals from one another in the longitudinal direction L. Similarly, in the abdominal-side portion 3, the plurality of elastic members 8 each extend from one end to the other end in the waist direction and are arranged at intervals from one another in the longitudinal direction L.

[0037] In the unfolded state shown in Fig. 2 , the disposable diaper 1 has a longitudinal direction L and a stretching direction D, which are perpendicular to each other and which is the waist circumference direction in the unfolded state. The disposable diaper 1 has a longitudinal centerline CL that passes through the center of the stretching direction D and extends along the longitudinal direction L, and a stretching-direction centerline CD that passes through the center of the longitudinal direction L and extends along the stretching direction D. Here, the directions and sides approaching the longitudinal centerline CL are respectively inward and inside of the stretching direction D. The directions and sides moving away from the longitudinal centerline CL are respectively outward and outside of the stretching direction D. On the other hand, the directions and sides approaching the stretching-direction centerline CD are respectively inward and inside of the longitudinal direction L. The directions and sides moving away from the stretching-direction centerline CD are respectively outward and outside of the longitudinal direction L.

[0038] The direction perpendicular to the longitudinal direction L and the stretching direction D is the thickness direction. "Skin side" and "non-skin side" respectively refer to the side relatively closer to and farther from the wearer's skin surface in the thickness direction of the disposable diaper 1 when the disposable diaper 1 is worn. In the thickness direction, the direction from the disposable diaper 1 toward the skin side is the skin side direction, and the direction from the disposable diaper 1 toward the non-skin side is the non-skin side direction. Figure 2 is a development view of the disposable diaper 1 when viewed in the thickness direction from the skin side direction toward the non-skin side direction.

[0039] Furthermore, viewing the disposable diaper 1 placed on a plane in the thickness direction from vertically above the plane is referred to as a "planar view," the shape grasped in the planar view is referred to as a "planar shape," and any direction within the plane including the longitudinal direction L and the stretching direction D is referred to as a "planar direction." In the longitudinal direction L, the side relatively closer to the ventral portion 3 or farther from the dorsal portion 2 is the ventral side or front side, and the side relatively closer to the dorsal portion 2 or farther from the ventral portion 3 is the dorsal side or rear side. The above definitions are also used for each material of the disposable diaper 1 and for the disposable diaper 1 in the state shown in Figure 1.

[0040] The phrase "along the longitudinal direction L" for a component, structure, shape, etc. includes not only the case where the component, etc. is parallel to the longitudinal direction L, but also the case where it is within a range of ±30° from the longitudinal direction L. Similarly, the phrase "along the extension direction D" for a component, etc. includes not only the case where the component, etc. is parallel to the extension direction D, but also the case where it is within a range of ±30° from the extension direction D. Curved or curved components, etc. are evaluated as described above for the tangents to each point on the curve, etc.

[0041] In the unfolded state, the abdominal section 3 and the back section 2 each have a generally rectangular shape that is elongated in the stretching direction D and are spaced apart from each other in the longitudinal direction L. The middle section 4 is located between the back section 2 and the abdominal section 3, and both side edges in the stretching direction D are recessed inward in the stretching direction D. The back section 2, the middle section 4, and the abdominal section 3 are integrally formed with each other. In another embodiment (not shown), the back section 2, the middle section 4, and the abdominal section 3 are formed separately from each other. The absorbent main body 6 has a generally rectangular shape. The absorbent main body 6 includes a liquid-permeable top sheet located on the skin side, a liquid-impermeable back sheet located on the non-skin side, and an absorbent body 6a located between the top sheet and the back sheet. The absorbent main body 6 has a pair of leakage prevention walls 7 arranged on both sides in the stretching direction D so as to face each other and extending along the longitudinal direction L. In addition, a three-piece disposable diaper has, when unfolded, a ventral portion 3, a dorsal portion 2, and a crotch portion between the ventral portion 3 and the dorsal portion 2, and the crotch portion joins the ventral portion 3 and the dorsal portion 2, and separates the ventral portion 3 and the dorsal portion 2 from each other.

[0042] Each of the ventral side portion 3 and the back side portion 2 is formed from a liquid-impermeable sheet material. Each of the ventral side portion 3 and the back side portion 2 is formed by laminating at least a sheet material located on the skin side and a sheet material located on the non-skin side in the thickness direction and joining them with an adhesive, heat sealing, or the like (adhesive, etc., the same applies hereinafter).

[0043] The abdominal portion 3 includes a plurality of elastic members 8 for waist gathering between the sheet member located on the skin side and the sheet member located on the non-skin side. The plurality of elastic members 8 are arranged at intervals in the longitudinal direction L and extend from one end to the other end in the stretch direction of the abdominal portion 3 along the stretch direction D. The plurality of elastic members 8 in the abdominal portion 3 belong to an elastic member group 9. Note that the elastic members 8 in the elastic member group 9 may extend from one end to the other end in the stretch direction of the abdominal portion 3 along the stretch direction D, except for a region that overlaps with the center of the absorbent body 6a in the thickness direction.

[0044] The back portion 2 also includes multiple elastic members 8 for waist gathering between the sheet member located on the skin side and the sheet member located on the non-skin side. The multiple elastic members 8 are spaced apart in the longitudinal direction L and belong to either of the elastic member groups 9a or 9b based on their positions. The elastic members 8 in the elastic member groups 9a and 9b extend from one end to the other end of the back portion 2 along the stretching direction D in the back portion 2. Note that the elastic members 8 in the elastic member group 9a may extend from one end to the other end of the back portion 2 in the stretching direction D in the stretching direction, except for a region overlapping with the center of the absorbent body 6a in the thickness direction. The positional relationship between the elastic member group 9a and the elastic member group 9b is such that the elastic member group 9a is relatively closer to the stretching direction centerline CD in the longitudinal direction L, and the elastic member group 9b is relatively farther from the stretching direction centerline CD in the longitudinal direction L.

[0045] The absorbent body 6a may have an absorbent core that absorbs and retains liquid and a core wrap that encases the absorbent core. The absorbent body 6a (core wrap), the topsheet, and the backsheet are each bonded with an adhesive. The backsheet of the absorbent main body 6 is bonded to a pair of leg gathers 5 at least at both ends in the stretching direction D. The pair of leg gathers 5 extend from both ends of the absorbent main body 6 in the stretching direction D to both outsides in the stretching direction D and extend along the longitudinal direction L.

[0046] Examples of the topsheet include liquid-permeable nonwoven fabrics or woven fabrics, synthetic resin films with liquid-permeable holes, composite sheets of these, etc. Examples of the backsheet include liquid-impermeable nonwoven fabrics or synthetic resin films, composite sheets of these, SMS nonwoven fabrics, etc. The shape of the absorbent body 6a is not limited to the above examples as long as it is long in the longitudinal direction L, and examples include a rectangle with rounded corners, a rectangle with outwardly convex short sides, and an hourglass shape.

[0047] The pair of leg gathers 5 extend along the longitudinal direction L and include elastic member groups 9c (leg elastic member groups) each consisting of a plurality of elastic members 8a (leg elastic members) spaced apart in the stretching direction D, and skin-side and non-skin-side sheet members sandwiching the elastic member groups 9c. The pair of leg gathers 5 are formed by disposing the pair of elastic member groups 9c between a pair of skin-side and non-skin-side sheet members. In other words, the pair of leg gathers 5 are integrally formed. The skin-side surfaces of the pair of leg gathers 5 in the center in the stretching direction D, i.e., the portion between the leg gathers 5, are joined to the non-skin-side surfaces of the absorbent main body 6 with an adhesive or the like. The elastic member groups 9c are joined to the outer sides of the skin-side and non-skin-side sheet members in the stretching direction D with an adhesive or the like. The elastic member groups 9c allow each leg gather 5 to stretch. In this embodiment, the skin-side and non-skin-side sheet members of the pair of leg gathers 5 are integral (the same) with the skin-side and non-skin-side sheet members of the abdominal portion 3 and the back portion 2. Therefore, the pair of leg gathers 5 (intermediate portion 4) and the abdominal portion 3 and the back portion 2 are integrally formed.

[0048] The sheet member used for the leg gathers 5 may be, for example, a hydrophobic nonwoven fabric or a hydrophilic nonwoven fabric. The types and materials of the nonwoven fabric will be described later. The elastic members 8a belonging to the elastic member group 9c are exemplified by rubber threads, and the types and materials of the elastic members will be described later.

[0049] In the disposable diaper 1, the pair of leg gathers 5 may be formed separately from each other and bridged by an exterior sheet member. In this case, both ends of the exterior sheet member in the stretching direction D are laminated to the inner ends of each of the pair of leg gathers 5 in the stretching direction D and joined with an adhesive or the like, thereby supporting and protecting the pair of leg gathers 5 from the non-skin side.

[0050] Each leak preventing wall 7 includes an elastic member group 9d (leak preventing elastic member group) consisting of a plurality of elastic members 8b (leak preventing elastic members) extending along the longitudinal direction L and arranged at intervals in the stretching direction D, and skin-side and non-skin-side sheet members sandwiching the elastic member group 9d. In the leak preventing wall 7, the skin-side and non-skin-side sheet members are formed by folding and stacking a single sheet member. The outer end of each leak preventing wall 7 in the stretching direction D is bonded to at least one of the top sheet, core wrap, and back sheet with an adhesive or the like to form a fixed end, and the inner end in the stretching direction D is spaced apart from the other sheets, including the top sheet, to form a free end. The elastic member group 9d is bonded to the sheet members near the free ends with an adhesive or the like.

[0051] The sheet material used for the leak-barrier 7 may be, for example, a hydrophobic nonwoven fabric or a hydrophilic nonwoven fabric. The types and materials of the nonwoven fabric will be described later. The elastic members 8b belonging to the elastic member group 9d are exemplified by rubber threads, and the types and materials of the elastic members will be described later.

[0052] In the back-side portion 2 and the ventral-side portion 3, the skin-side and non-skin-side sheet members and the multiple elastic members 8 are indirectly fixed to each other by, for example, gripping the skin-side and non-skin-side sheet members by bonding them together. The elastic members 8 stretch in the stretching direction D, stretching the waist portion WP. In the leg gathers 5 and the leakage barrier walls 7, the skin-side and non-skin-side sheet members and the multiple elastic members 8a, 8b are directly fixed to each other by, for example, bonding with an adhesive. The elastic members 8a, 8b stretch in the longitudinal direction L, stretching the leg gathers 5 and the leakage barrier walls 7. When the disposable diaper 1 is in an unfolded state, the portions of the back-side portion 2, the ventral-side portion 3, the leg gathers 5, and the leakage barrier walls 7 that include elastic members constitute a laminate in which the skin-side sheet member, the elastic members, and the non-skin-side sheet member are layered in this order in the thickness direction.

[0053] The laminate comprises a skin-side sheet member, a non-skin-side sheet member, and at least one elastic member, the non-skin-side surface of the skin-side sheet member and the skin-side surface of the non-skin-side sheet member being joined together, and at least one elastic member being fixed between the non-skin-side surface of the skin-side sheet member and the skin-side surface of the non-skin-side sheet member. Furthermore, the elastic member in the laminate does not intersect with the skin-side sheet member and the non-skin-side sheet member.

[0054] The nonwoven fabric of the sheet members constituting the back side portion 2, the ventral side portion 3, the leg gathered portions 5, and the leak-barrier walls 7 is not particularly limited, and examples thereof include spunbond nonwoven fabric, meltblown nonwoven fabric, airlaid nonwoven fabric, air-through nonwoven fabric, etc. The material of the nonwoven fabric is not particularly limited as long as it can be used for sanitary products, and examples thereof include olefin resins such as polyethylene and polypropylene, polyamide resins such as 6-nylon and 6,6-nylon, and polyester resins such as polyethylene terephthalate and polybutylene terephthalate.

[0055] The type of elastic members 8, 8a, 8b is not particularly limited, and examples thereof include thread-, strip-, or sheet-shaped rubber. The material of the elastic members 8, 8a, 8b is not particularly limited, and examples thereof include polyurethane elastic fiber, styrene-butadiene rubber, and urethane rubber. The characteristics of the elastic members 8, 8a, 8b, such as the cross-sectional size (wire diameter, etc.) and elongation ratio, are appropriately selected depending on the magnitude of the tightening force corresponding to the position within the waist portion WP, the magnitude of the tightening force corresponding to the position within the leg gathered portion 5, and the function of the leakage barrier 7, respectively.

[0056] The laminate is composed of a skin-side sheet member (first sheet), a non-skin-side sheet member (second sheet), and multiple elastic members 8. An example of a laminate is the back-side portion 2. The following description of the laminate will use a region R of the back-side portion 2 as an example. Region R is a portion of the laminate in which multiple elastic members 8 in the back-side portion 2 are secured by the first and second sheets. Region R may be set at any position and shape within the back-side portion 2 and abdominal-side portion 3, as long as it secures the elastic members 8, which extend continuously in the stretch direction D, to the first and second sheets within the waist portion WP and does not overlap with the leg gathers 5 and the absorbent main body 6. The region R described below is a square region within the back-side portion 2, representing both the first and second sheets. The "inner surface of the sheets" is a collective term for the inner surfaces of the first and second sheets that contact the elastic members 8. The sheet outer surface is a general term for the first sheet outer surface and the second sheet outer surface, which are exposed surfaces to the outside.

[0057] FIG. 3 shows a region R of the laminate 10 in the skin side direction T １ The area R includes the four elastic members 8 and the fixing portions 15 around them. １ The sheet member that can be seen when viewed from above is the first sheet 11.

[0058] When the fixing part 15 includes a heat-sealed part, at least two fixing parts 15 (a pair of opposing heat-sealed parts 16) are arranged on the inner surface of the sheet of the laminate 10. The pair of opposing heat-sealed parts 16 are arranged at an interval in the longitudinal direction L so as to be able to grip the elastic member 8 having an outer diameter d1 when the laminate 10 is maximally stretched (pulled) in the stretching direction D. When the fixing part 15 performs only heat fusion, the heat-sealed part where heat fusion is performed is the fixing part 15, and two heat-sealed parts opposing each other in the longitudinal direction L with one elastic member 8 sandwiched therebetween are the pair of opposing heat-sealed parts 16.

[0059] At least one pair of opposing heat-sealed portions 16 of the laminate 10 are formed during manufacturing so as to be able to grip the elastic member 8 having the outer diameter d1 as described above when the elastic member 8 is stretched in the stretching direction D so that its outer diameter is smaller than the outer diameter d1. The elastic member 8 then contracts from its stretched state in the stretching direction D to its natural state, increasing its outer diameter. That is, the outer diameter of the elastic member 8 at a position other than that gripped by the at least one pair of opposing heat-sealed portions 16 becomes an outer diameter d2 that is larger than the outer diameter d1. As a result, in the formed laminate 10, the elastic member 8 is gripped by the at least one pair of opposing heat-sealed portions 16. Furthermore, when the laminate 10 is maximally stretched in the stretching direction D, the elastic member 8 is gripped by the pair of opposing heat-sealed portions 16 even when its outer diameter becomes d1.

[0060] Since the multiple elastic members 8 are arranged at intervals in the longitudinal direction L, the opposing heat-sealed portions 16 are also arranged at intervals in the longitudinal direction L. The heat-sealed portions (fixed portions 15) constituting the opposing heat-sealed portions 16 do not overlap each other. The heat-sealed portions (fixed portions 15) are arranged at predetermined intervals in the stretching direction D. The predetermined intervals are the seal pitch during manufacturing, and are, for example, 8 mm.

[0061] In the laminate 10, the first sheet 11 and the second sheet 12 (a pair of sheet members) are intermittently joined together at a plurality of heat-sealed portions (fixing portions 15) that are discretely arranged in the stretching direction D and the longitudinal direction L. The heat-sealed portions are formed using a well-known welding method, such as ultrasonic welding or heat welding. The formation of the heat-sealed portions is not limited to the pair of sheets sandwiching the elastic member 8, and all layers stacked in the laminate 10 having the pair of sheets sandwiching the elastic member 8 may be joined by embossing or the like. In this case, depressions in the heat-sealed portions formed by embossing or the like can be confirmed from the appearance of the laminate 10.

[0062] The elastic member 8, which is held at the outer diameter d1 by the opposing heat-sealed portions 16, is subjected to a repulsive force (a force that tries to expand in the longitudinal direction L) that tries to increase the outer diameter from d1. Furthermore, if the elastic member 8 is cut between the opposing heat-sealed portions 16 in the stretching direction D, the elastic member 8 will shrink from the cut point toward the stretching direction D, but since the outer diameter increases during the shrinkage, the elastic member 8 will not pass through the opposing heat-sealed portions 16, and slipping out of the rubber can be prevented.

[0063] Fig. 4 is a cross-sectional view of the laminate 10 constituting the range R along the line IV-IV in Fig. 3. Fig. 4 shows the configuration when the line IV-IV in Fig. 3 is viewed from the inside to the outside in the longitudinal direction L, but the configuration is the same when viewed from the outside to the inside in the longitudinal direction L.

[0064] The laminate 10 is formed by laminating a first sheet 11 made of a plurality of fibers and a second sheet 12 made of a plurality of fibers in the thickness direction. The thickness direction is the skin direction T １ and the non-skin direction T ２ The first sheet 11 is a sheet member on the skin side of the laminate 10, i.e., a sheet member that constitutes the skin side portion of the back side portion 2. The second sheet 12 is a sheet member on the non-skin side of the laminate 10, i.e., a sheet member that constitutes the non-skin side portion of the back side portion 2. At least one of the first sheet inner surface 11a and the second sheet inner surface 12a contains thermoplastic fibers having protrusions containing inorganic particles. In other words, the joining surface between the first sheet 11 and the second sheet 12 contains thermoplastic fibers having protrusions containing inorganic particles.

[0065] The first sheet 11 is ２ The first sheet inner surface 11a is the surface on the side opposite to the first sheet inner surface 11a in the thickness direction. １ The second sheet 12 has a first sheet outer surface 11b which is a surface facing the skin in the direction T １ a second sheet inner surface 12a, which is the surface on the side opposite to the second sheet inner surface 12a in the thickness direction, and a non-skin direction T ２ and a second sheet outer surface 12b that is a surface facing the first sheet 11a. In the laminate 10, the first sheet inner surface 11a and the second sheet inner surface 12a are joining surfaces where joining is performed. Note that the first sheet 11 and the second sheet 12 may be formed by folding a single sheet and stacking them with the elastic member 8 sandwiched between them.

[0066] FIG. 5 is a cross-sectional view of the laminate 10 constituting the range R along line V-V in FIG. 3. As shown in FIG. 5, the laminate 10 includes a first sheet 11, a second sheet 12, and an elastic member 8 disposed between the first sheet 11 and the second sheet 12 and stretched in a stretching direction D that does not intersect with the thickness direction T of the first sheet 11 and the second sheet 12. The first sheet 11 and the second sheet 12 contact the elastic member 8 at the first sheet inner surface 11a and the second sheet inner surface 12a, respectively. The laminate 10 includes a plurality of fixing portions 15 that fix the elastic member 8 to the first sheet 11 and the second sheet 12 along the stretching direction D. The fixing portions 15 also bond the first sheet 11 and the second sheet 12 together. Note that FIG. 5 shows the configuration when line V-V in FIG. 3 is viewed from the outside toward the inside of the stretching direction D, but the configuration is similar when viewed from the inside toward the outside of the stretching direction D.

[0067] The fixing portion 15 functions as a joining portion between the first sheet 11 and the second sheet 12, i.e., a joining portion between the first sheet inner surface 11a and the second sheet inner surface 12a. The joining portion has at least the function of a heat-sealing portion that performs heat fusion. The first sheet 11 and the second sheet 12 in the fixing portion 15 shown in Fig. 5 have an increased fiber density due to compression, such as embossing, performed on the first sheet 11 and the second sheet 12 during heat fusion, and are therefore thinner than other portions.

[0068] 5, the elastic members 8 are shown larger than the first sheet 11 and the second sheet 12 to facilitate understanding of the invention, but this does not represent the actual relationship between the elastic members 8 and the laminate 10. Furthermore, the distance between the multiple elastic members 8 does not represent the actual positional relationship in the longitudinal direction L. Furthermore, because the elastic members 8 are fixed to the fixing portions 15, the first sheet 11 and the second sheet 12 that come into contact with the elastic members 8 have almost no thickness.

[0069] In the laminate 10, a plurality of elastic members 8 that are stretchable in the extension direction D are arranged at intervals in the longitudinal direction L between the first sheet 11 and the second sheet 12 (between a pair of sheet members) that are joined by a plurality of fixing portions 15.

[0070] Fig. 6 is an SEM photograph of the outer surface of a laminate 10 having a plurality of fixing portions 15 formed by thermal fusion. In the laminate shown in Fig. 6, both the first sheet 11 and the second sheet 12 are SMS nonwoven fabrics, and only the inner surface of one of the sheets is provided with thermoplastic fibers having protrusions containing inorganic particles, and the thermoplastic resin used for the first sheet 11 and the second sheet 12 is polypropylene.

[0071] The heat-sealed portions are formed by a known welding method such as ultrasonic welding or thermal welding of a plurality of thermoplastic fibers. The heat-sealed portions are formed by melting the thermoplastic fibers and then solidifying them. Therefore, inorganic particles contained in the protrusions of the thermoplastic fibers are embedded in the molten resin. As a result, when the plurality of fixing portions 15 only have a plurality of heat-sealed portions, the fixing portions 15 are smooth on the outer surface of the sheet (the surface of the laminate 10) as shown in FIG. 6, and no protrusions are present.

[0072] Fig. 7 shows a typical example of thermoplastic fibers 20 constituting the inner surface of a sheet such as the first inner surface 11a, in which the proportion of inorganic particles in the thermoplastic fibers is 21.0 mass%. The thermoplastic fibers are formed with a plurality of protrusions 21 dispersed on the fiber surface. The fiber diameter of the thermoplastic fibers 20 in the portion where the plurality of protrusions 21 are formed is larger than the fiber diameter in the portion where the plurality of protrusions 21 are not formed, depending on the size of the protrusions 21. Note that the inorganic particles in Fig. 7 are CaCO ３ is used.

[0073] On the other hand, Figure 8 shows a typical example of a non-convex thermoplastic fiber, which is a fiber other than the thermoplastic fiber 20, in which the proportion of inorganic particles in the fiber is 0 mass%. The non-convex thermoplastic fiber 23 has no convex portions on the fiber surface and has a smooth surface. The convex portions 21 are portions that protrude outward from the surface of the thermoplastic fiber 20.

[0074] When the fixing portion 15 of the laminate 10 functions as a heat-sealed portion by heat fusion, the first sheet 11 and the second sheet 12 are joined to each other in indirectly fixing the elastic member 8 by the heat-sealed portion, so that the inner surface 11a of the first sheet and the inner surface 12a of the second sheet come into contact with the elastic member 8, respectively, and the elastic member is gripped in the thickness direction.

[0075] Furthermore, in the regions where the first sheet inner surface 11a and the second sheet inner surface 12a contact the elastic member 8, the plurality of protrusions 21 of the thermoplastic fibers 20 come into contact with the elastic member 8, increasing the frictional resistance of the elastic member 8. The increased frictional resistance makes it easier for the laminate 10 to fix the elastic member 8, and can suppress slippage of the elastic member 8. Furthermore, since each of the plurality of protrusions 21 contains inorganic particles, the laminate 10 can stably form the protrusions 21.

[0076] When the first sheet inner surface 11a of the laminate 10 has thermoplastic fibers 20 having protrusions 21, a plurality of thermoplastic fibers 20 are arranged at least on the surface of the first sheet inner surface 11a. The thermoplastic fibers may be arranged in layers on the first sheet 11. Similarly, when the second sheet inner surface 12a has thermoplastic fibers 20 having protrusions 21, a plurality of thermoplastic fibers 20 are arranged at least on the surface of the second sheet inner surface 12a, and the thermoplastic fibers 20 may be arranged in layers on the second sheet 12.

[0077] Furthermore, the first sheet 11 may also contain thermoplastic fibers 20 having multiple convex portions 21, or fibers different from the thermoplastic fibers 20 having multiple convex portions 21 and the non-convex thermoplastic fibers 23, even on the first sheet outer surface 11b exposed to the outside.

[0078] Specifically, in the laminate 10 including the thermoplastic fibers 20 having the plurality of protrusions 21 on the first sheet inner surface 11a, a first sheet inner surface layer, which is a fiber layer formed on the first sheet inner surface 11a side, i.e., the inner surface side, and a first sheet outer surface layer, which is a fiber layer formed on the first sheet outer surface 11b side, i.e., the outer surface side, may be laminated. Furthermore, another fiber layer may be laminated between the first sheet inner surface layer and the first sheet outer surface layer. The same applies to the second sheet 12. Furthermore, when the first sheet 11 or the second sheet 12 includes a plurality of fiber layers, the type of fiber in each fiber layer may be different from that in the other fiber layers.

[0079] In the laminate 10, the thermoplastic fibers 20 containing inorganic particles are biased toward the first sheet inner surface layer (or the second sheet inner surface layer) that contacts the elastic member 8, so that the mass ratio of the inorganic particles between the first sheet inner surface 11a and the first sheet outer surface 11b (or the second sheet inner surface 12a and the second sheet outer surface 12b) is not uniform.

[0080] When the first sheet inner surface 11a includes thermoplastic fibers 20 having a plurality of protrusions 21, the mass proportion of inorganic particles in the first sheet inner surface 11a is higher than the mass proportion of inorganic particles in the first sheet outer surface 11b. Similarly, when the second sheet inner surface 12a includes thermoplastic fibers 20 having a plurality of protrusions 21, the mass proportion of inorganic particles in the second sheet inner surface 12a is higher than the mass proportion of inorganic particles in the second sheet outer surface 12b.

[0081] As a result, in the laminate 10, the first sheet outer surface 11b (or the second sheet outer surface 12b), which has fewer inorganic particles, has a lower fineness and longer fiber length than the first sheet inner surface 11a (or the second sheet inner surface 12a), which has more inorganic particles. This increases the amount of fiber used for heat fusion and strengthens the bond strength of the heat-fused portion. The increased bond strength makes it difficult for the first sheet and the second sheet to peel apart, and the elastic member can be more firmly fixed, thereby preventing the elastic member from slipping.

[0082] In this embodiment, in the laminate 10, at least one of the first sheet 11 and the second sheet 12 contains small-diameter thermoplastic fibers that have a smaller fiber diameter than the thermoplastic fibers 20 and do not contain inorganic particles. When the first sheet 11 contains small-diameter thermoplastic fibers, the first sheet 11 has a first-sheet intermediate layer containing small-diameter thermoplastic fibers between the first-sheet inner surface 11a and the first-sheet outer surface 11b. When the second sheet 12 contains small-diameter thermoplastic fibers, the second sheet 12 has a second-sheet intermediate layer containing small-diameter thermoplastic fibers between the second-sheet inner surface 12a and the second-sheet outer surface 12b.

[0083] For example, the first sheet 11 may be an SMS nonwoven fabric (spunbond-meltblown-spunbond nonwoven fabric) having a first sheet inner surface layer (SB layer: spunbond layer) which is the layer of the first sheet inner surface 11a, a first sheet intermediate layer (MB layer: meltblown layer) which is the layer of the first sheet outer surface 11b, and a first sheet outer surface layer (SB layer: spunbond layer) which is the layer of the first sheet outer surface 11b. The second sheet 12 may also be an SMS nonwoven fabric having a similar configuration.

[0084] As shown in FIG. 9, the second sheet 12 is １ From non-skin direction T ２ The layers are laminated in the order of the non-convex thermoplastic fiber layer 34, the small diameter thermoplastic fiber layer 32, and the non-convex thermoplastic fiber layer 34 toward the first sheet outer surface. That is, the non-convex thermoplastic fiber layer 34 is provided in the second sheet inner surface layer and the second sheet outer surface layer, and the small diameter thermoplastic fiber layer 32 is provided in the second sheet intermediate layer. The small diameter thermoplastic fiber layer 32 is composed of small diameter thermoplastic fibers that do not contain inorganic particles as the first sheet intermediate layer. The non-convex thermoplastic fiber layer 34 is composed of non-convex thermoplastic fibers 23 that do not have convex portions 21 as the first sheet outer surface layer.

[0085] As shown in FIG. 10, the first sheet 11 is ２ From the skin direction T １ The thermoplastic fiber layer 30, the small diameter thermoplastic fiber layer 32, and the non-convex thermoplastic fiber layer 34 are laminated in this order toward the center of the sheet. That is, the first sheet has a thermoplastic fiber layer 30 as an inner surface layer, a small diameter thermoplastic fiber layer 32 as an intermediate layer, and a non-convex thermoplastic fiber layer 34 as an outer surface layer. The thermoplastic fiber layer 30 is composed of thermoplastic fibers 20 having a plurality of convex portions 21.

[0086] A laminate 10 including either the second sheet 12 shown in Figure 9 or the first sheet 11 shown in Figure 10 includes either a first sheet intermediate layer or a second sheet intermediate layer containing small-diameter thermoplastic fibers, and the small-diameter thermoplastic fibers do not contain inorganic particles. Therefore, the fiber length of the thermoplastic fibers is increased even more than in a laminate composed of sheets having a single-layer or two-layer structure containing inorganic particles, the bonding strength of the heat-sealed parts is increased, and slippage of the elastic member 8 can be suppressed.

[0087] Figure 11 is a cross-sectional view of a laminate 10 in which the second sheet 12 described in Figure 9 and the first sheet 11 described in Figure 10 are bonded together. The laminate 10 shown in Figure 11 includes a first sheet intermediate layer and a second sheet intermediate layer containing small-diameter thermoplastic fibers. Because the small-diameter thermoplastic fibers do not contain inorganic particles, the fiber lengths of the thermoplastic fibers are longer than when only one of the first sheet intermediate layer and the second sheet intermediate layer contains small-diameter thermoplastic fibers. This further increases the bonding strength of the heat-sealed portions of the laminate 10, further suppressing slippage of the elastic member 8. Note that Figures 9 to 11 may also include a configuration in which the first sheet inner surface layer is a non-convex thermoplastic fiber layer 34 and the second sheet inner surface layer is a thermoplastic fiber layer 30.

[0088] The thermoplastic fibers 20 are continuous fibers that are continuously produced, for example, by heating and melting a raw resin in an extruder and discharging it from a spinneret. Examples of the thermoplastic fibers 20 include spunlaid fibers such as spunbond fibers and meltblown fibers. The fiber length of the thermoplastic fibers 20 can be said to be the same as the length of the first sheet 11 and the second sheet 12 in terms of the production method, but is at least 10 cm or more. By making the fiber length 10 cm or more, the thermoplastic fibers can be continuously long, making them less likely to come out of the first sheet 11 and the second sheet 12. In particular, when the basis weight of the first sheet 11 and the second sheet 12 is low (e.g., 30 g / m ２ The effect is remarkable. In this embodiment, spunbond fibers are used.

[0089] The average fiber diameter (diameter) of the thermoplastic fibers 20 is, for example, 5 to 30 μm, preferably 10 to 25 μm, and more preferably 12 to 20 μm. By setting the average fiber diameter to 5 μm or more, the fibers are less likely to be cut along the way, making them more likely to be continuously long and less likely to come out of the first sheet 11 (or the second sheet 12). By setting the average fiber length to 30 μm or less, the fibers are less likely to become thicker, making it easier to make the first sheet 11 (or the second sheet 12) flexible. These effects are particularly noticeable when the basis weight of the first sheet 11 (or the second sheet 12) is low (e.g., 30 g / m2 or less).

[0090] The thermoplastic fiber 20 is made of a thermoplastic resin. Examples of the thermoplastic resin include olefin resins such as polyethylene and polypropylene, polyamide resins such as 6-nylon and 6,6-nylon, and polyester resins such as polyethylene terephthalate and polybutylene terephthalate. In this embodiment, an olefin resin is used, and polypropylene is preferably used. The thermoplastic fiber 20 may further contain known materials that can be used to form the thermoplastic fiber 20.

[0091] The thermoplastic fiber 20 contains a plurality of inorganic particles in addition to a thermoplastic resin. Examples of inorganic particles include metal oxides, hydroxides, carbonates, sulfates, phosphates, silicates, and silicon compounds. Examples of metal oxides include titanium oxide, zinc oxide, zirconium oxide, magnesium oxide, and alumina. Examples of metal hydroxides include magnesium hydroxide, calcium hydroxide, iron hydroxide, and copper hydroxide. Examples of metal carbonates include calcium carbonate, magnesium carbonate, and zinc carbonate. Examples of metal sulfates include barium sulfate, calcium sulfate, and zinc sulfide. Examples of metal phosphates include calcium phosphate. Examples of metal silicates include aluminum silicate, mica, talc, clay, kaolin, and titanium mica. Examples of metal silicon compounds include silica and colloidal silica. In this embodiment, carbonates are used, and calcium carbonate (CaCO ３ ) is preferably used.

[0092] The material of the fibers of the second sheet 12 (or the first sheet 11) that does not include the thermoplastic fibers 20 having the protrusions 21 is the above-mentioned thermoplastic resin, but does not contain inorganic particles, i.e., non-convex thermoplastic fibers 23 that do not have the protrusions 21. Therefore, the non-convex thermoplastic fibers 23 are essentially fibers made from a conventional thermoplastic resin. Note that the non-convex thermoplastic fibers 23 may contain inorganic particles in a proportion (e.g., less than 4.5% by mass) that does not cause the inorganic particles to form irregularities on the surface.

[0093] The basis weight of the first sheet 11 and the second sheet 12 is, for example, 5 to 30 g / m ２ and 5 to 25 g / m ２ is preferred, and 10 to 20 g / m ２ It is more preferable that the basis weight of the first sheet 11 and the second sheet 12 is 5 g / m ２ By setting the basis weight of the first sheet 11 and the second sheet 12 to 30 g / m or more, it is possible to easily maintain the laminate 10 in a stable shape. ２ By setting the following, the laminate 10 can be easily made flexible.

[0094] The protrusions 21 are formed of inorganic particles or the like. Examples of the protrusions 21 include inorganic particles that break through the surface from the inside of the thermoplastic fiber 20 and protrude outward from the surface, and inorganic particles that are located roughly on the surface of the thermoplastic fiber 20 and protrude outward from the surface. The protrusions 21 may also be formed of a thermoplastic resin, and the surface of the thermoplastic fiber 20 may include a portion that protrudes outward from the surrounding surface. Each of the multiple protrusions 21 has a variety of sizes and shapes, and the shapes are different from one another.

[0095] The height of the protrusions 21 (based on the surface of the thermoplastic fibers 20) can be, for example, 1 / 50 to 1 / 2 of the average fiber diameter of the thermoplastic fibers 20, preferably 1 / 40 to 1 / 3, and more preferably 1 / 30 to 1 / 4. When the height of the protrusions 21 is 1 / 50 or more of the average fiber diameter, an anchor effect for the coating liquid and an increase in the contact area can be more reliably achieved when a coating liquid such as an adhesive is applied to the first sheet inner surface 11a (thermoplastic fibers 20). When the height of the protrusions 21 is 1 / 2 or less of the average fiber diameter, the protrusions 21 are less likely to fall off the surface of the thermoplastic fibers 20. However, some protrusions may have a height less than 1 / 50 of the average fiber diameter.

[0096] The size of the protrusions 21 in a planar view can be, for example, approximately the height of the protrusions 21. That is, the size of the protrusions 21 in a planar view can be, for example, 1 / 20 to 1 / 2 of the average fiber diameter of the thermoplastic fibers 20, preferably 1 / 20 to 1 / 3, and more preferably 1 / 20 to 1 / 4. When the size of the protrusions 21 is 1 / 20 or more of the average fiber diameter, an anchor effect for the coating liquid and an increase in the contact area are more reliably achieved when a coating liquid is applied to the first sheet inner surface 11a (thermoplastic fibers 20). When the size of the protrusions 21 is 1 / 2 or less of the average fiber diameter, the protrusions 21 are less likely to fall off from the surface of the thermoplastic fibers 20. The size of the protrusions 21 in a planar view is the length of the longest portion of the protrusions 21 projected onto the surface of the thermoplastic fibers 20. However, some protrusions may have a size less than 1 / 20 of the average fiber diameter.

[0097] The number of protrusions 21 in a planar view on the surface of the thermoplastic fiber 20 per 10 μm × 10 μm area on the surface of the thermoplastic fiber 20 is, for example, 2 to 200, preferably 10 to 150, and more preferably 10 to 100. Having two or more protrusions 21 ensures an anchor effect for the coating liquid and an increase in contact area when the coating liquid is applied to the inner surface of the sheet. Having 200 or less protrusions 21 can prevent a decrease in flexibility of the inner surface of the sheet (laminate 10).

[0098] The average particle size (diameter) of the inorganic particles (protrusions 21) is, for example, 0.1 to 15 μm, preferably 0.5 to 12 μm, and more preferably 1 to 10 μm. By setting the average particle size to 0.1 μm or more, when applying a coating liquid to the inner surface of the sheet, the anchoring effect for the coating liquid and the increase in contact area are more reliably achieved. By setting the average particle size to 15 μm or less, the inorganic particles are less likely to fall off from the surface of the thermoplastic fiber 20.

[0099] The inorganic particles (protrusions 21) are covered with a coating material at least at the raw material stage during manufacturing. This allows the inorganic particles to be stably dispersed within the fiber raw material (e.g., thermoplastic resin). Examples of such coating materials include organic materials. Examples of organic materials include fatty acids, their salts, and their esters, and examples of fatty acids include stearic acid.

[0100] In the laminate of the present disclosure, the mass ratio of inorganic particles (protrusions) in the thermoplastic fibers in at least one of the first sheet and the second sheet is 4.5% or more and 21.0% or less. Having an inorganic particle ratio of 4.5% or more can prevent rubber loss, i.e., prevent slippage of the elastic member. Furthermore, having an inorganic particle ratio of 4.5% or more can more reliably form protrusions on the thermoplastic fibers.

[0101] If the proportion of inorganic particles is more than 21.0%, problems occur such as nozzle clogging, inorganic particle dropout, and a decrease in the amount of melted thermoplastic resin due to a decrease in thermoplastic resin (deterioration of thermal fusion properties), etc. Therefore, by setting the proportion of inorganic particles in the thermoplastic fiber to 21.0% or less, the inorganic particles can be made less likely to drop out from the surface of the thermoplastic fiber.

[0102] The laminate containing inorganic particles at a mass ratio of not more than the upper limit can prevent the inorganic particles from falling off from the thermoplastic fibers, and the laminate containing inorganic particles at a mass ratio of not less than the lower limit can improve the thermal fusion properties of the thermally fused portions and the anchor effect of the adhesive portions. Furthermore, the improved thermal fusion properties reduce the temperature and pressure required for thermal fusion in forming the laminate, thereby preventing breakage of the elastic member.

[0103] In the laminate of the present disclosure, the thermal conductivity of at least one of the first sheet and the second sheet at 160°C is 0.191 W / (m·k) or more and 0.224 W / (m·k) or less. W is the amount of electric heat, m is the thickness in the direction of thermal conduction, and k is the temperature. This improves the thermal conductivity of the first sheet containing inorganic particles and the second sheet, thereby increasing the area of ​​the heat-sealed portion and further improving the heat-sealing properties.

[0104] The values ​​of various properties are determined by the following measurement methods.

[0105] <Basis Weight of Laminate> The measurer performs the steps (1) to (4). (1) Disassemble the laminate, remove the elastic member, and collect the first and second sheets. (2) Cut out five samples of a predetermined size (e.g., 100 mm x 100 mm) from each of the first and second sheets. (3) Measure the mass of each of the five cut samples using a direct reading balance (electronic balance HF-300 manufactured by Kensei Kogyo Co., Ltd.). (4) Calculate the mass per unit area of ​​the laminate from the average mass of each of the five samples to determine the basis weight (g / m) of the laminate. ２ )

[0106] <Fiber fineness> The fineness is determined by the average fiber diameter (described later), resin density (e.g., polypropylene 0.91 g / cm ３ ), inorganic particle density (e.g., calcium carbonate 2.71 g / cm ３ ), and the proportion of inorganic particles in the fiber (described later), the fiber weight per 10,000 m (Dtex = g / 10,000 m) is calculated to obtain the fineness.

[0107] <Average Fiber Diameter> The measurer performs steps (1) to (5). (1) Disassemble the laminate, remove the elastic member, and collect the first and second sheets. (2) Cut the first and second sheets into 10 mm x 10 mm pieces to prepare samples. (3) Place the sample on a slide, drip an appropriate amount of glycerin onto the sample until the entire sample is immersed in glycerin, and then place a cover glass over it. (4) Observe the surface of the sample at 1000x magnification using an optical microscope (Keyence Corporation VHC-100 Digital Microscope Lens VH-Z450). (5) Measure the fiber diameter of fibers exposed on the surface of the sample at 50 locations, and use the average value as the average fiber diameter.

[0108] <Number of Convex Parts> The measurer performs steps (1) to (6). (1) Disassemble the laminate, remove the elastic member, and collect the first and second sheets. (2) Cut the first and second sheets into 1 cm x 1 cm pieces to prepare samples. (3) Place the samples on the sample stage of an electron microscope (FlexSEM1000, manufactured by Hitachi High-Tech Corporation) with one side of the first and second sheets facing upward. (4) Photograph an image of the sample surface at 2000x magnification. (5) In the photographed image, count the number of convex parts present in a given area (e.g., 10 μm x 10 μm) on the surface of a specific fiber, and use this number as the number of convex parts per given area for that sample. (6) Perform steps (1) to (5) above for five samples, and calculate the average value to obtain the final number of convex parts per given area.

[0109] <Size of protrusions> The measurer performs steps (1) to (6). Steps (1) to (4) are the same as for <Number of protrusions>. (5) In the captured image, for protrusions in a predetermined region (e.g., 10 μm x 10 μm) on the surface of the fiber, the length of the longest part of each protrusion when the surface of the fiber is viewed in plan is determined as the size (range) of the protrusions. Note that the average of the sizes of all of these protrusions is the average size of the protrusions for that sample. (6) Steps (1) to (5) above are performed for five samples each, and the average of the upper and lower limits of the range is calculated to determine the final size (range) of the protrusions. Note that the average of the sizes of all of these protrusions is the final average size of the protrusions.

[0110] <Average particle size of inorganic particles> The measurer performs steps (1) to (6). Steps (1) to (4) are the same as for <Number of convex portions>. (5) In the captured image, for inorganic particles in a predetermined region (e.g., 10 μm x 10 μm) on the surface of the fiber, the length of the longest part of each inorganic particle is determined when the surface of the fiber is viewed in plan, and the average is calculated to be the average particle size of the inorganic particles for that sample. (6) Steps (1) to (5) above are performed for each of five samples, and the average is calculated to be the final average particle size of the inorganic particles.

[0111] <Height of Convex Portions> The measurer performs steps (1) to (6). Steps (1) to (4) are the same as for <Number of Convex Portions>. (5) In the captured image, for convex portions within a predetermined range (e.g., 10 μm in length) at the edge in the stretching direction of the fiber, the height of each convex portion is measured relative to the surface of the fiber to determine the height (range) of the convex portions. Note that the average of all the heights of these convex portions is the average height of the convex portions for that sample. (6) Steps (1) to (5) above are performed for five samples each, and the average of the upper and lower limits of the range is calculated to determine the final height (range) of the convex portions. Note that the average of all the heights of these convex portions is the final average height of the convex portions.

[0112] <Proportion of Inorganic Particles in Fibers> The measurer performs steps (1) to (9). (1) Disassemble the laminate, remove the elastic member, and collect the first and second sheets. (2) Cut the first and second sheets into 5 cm x 5 cm samples. (3) Measure the mass of the sample (mass A). (4) Immerse the sample in an organic solvent that can dissolve resin but not inorganic particles (e.g., aromatic hydrocarbons such as benzene or toluene at 80°C or higher) to dissolve only the resin. (5) Filter the organic solvent in which the resin has dissolved to extract the inorganic particles. (6) Measure the mass of the extracted inorganic particles (mass B). (7) Determine the proportion of inorganic particles in the thermoplastic fibers for that sample from mass A and mass B. (8) Perform steps (1) to (7) above for five samples and calculate the average to determine the final proportion of inorganic particles in the thermoplastic fibers. (9) Calculate the average proportion of inorganic particles in the laminate from the average proportion of inorganic particles in the first and second sheets.

[0113] The method for manufacturing the laminate is as described below. The laminate manufacturing method can be carried out by a manufacturer using a laminate manufacturing apparatus (not shown) for manufacturing the laminate. The laminate manufacturing apparatus includes two nonwoven fabric manufacturing apparatuses for manufacturing SMS nonwoven fabrics, an elastic member manufacturing apparatus for manufacturing an elastic member, and a processing apparatus for fixing the elastic member between two sheets of nonwoven fabric. Conventional spunbond nonwoven fabrics that do not contain inorganic particles, conventional meltblown nonwoven fabrics that do not contain inorganic particles, and elastic members can be obtained using known manufacturing methods and manufacturing apparatuses. One of the two nonwoven fabric manufacturing apparatuses manufactures a sheet containing inorganic particles. Two examples of manufacturing methods for manufacturing a nonwoven fabric containing inorganic particles are given below.

[0114] The following describes a first example (spunbond nonwoven fabric) of the method for producing a sheet (nonwoven fabric) containing inorganic particles that constitutes the laminate 10. The nonwoven fabric production apparatus includes a traction device, a net conveyor, and the like.

[0115] The manufacturer prepares a raw resin mixture containing a masterbatch containing at least one type of inorganic particles (preferably coated with a coating material) and at least one type of thermoplastic resin. The ratio of inorganic particles in the raw resin is the same as the ratio of inorganic particles in the thermoplastic fibers. The nonwoven fabric manufacturing apparatus then heats and melts the raw resin in an extruder and continuously extrudes the raw resin in a fibrous form vertically downward from a spinneret connected to the extruder. The nonwoven fabric manufacturing apparatus then cools the extruded fibrous resin from the side with cold air while stretching it to a predetermined fiber diameter using a pulling device (ejector) to form thermoplastic fibers. The nonwoven fabric manufacturing apparatus then spreads and deposits the formed thermoplastic fibers on a net conveyor to form a web.

[0116] Here, when cooling the fibrous resin discharged from the spinneret with cold air, the nonwoven fabric manufacturing apparatus blows cold air from the side at a position closer to the spinneret than usual, directly below the spinneret (for example, 1 to 30 cm below the spinneret in the vertical direction), in addition to the normal cold air. This cold air is cold air with a higher flow rate than usual or cold air with a lower temperature than usual. This is thought to cause the formation of convex portions by the following mechanism (not limited to this). This separate cold air tends to harden the surface of the resin more quickly than usual, making it easier for inorganic particles located near the surface to remain on the surface. As a result, even if the diameter of the resin becomes smaller due to stretching and the inorganic particles are exposed to the surface, the inorganic particles are maintained in a state of being retained on the surface, and convex portions are formed.

[0117] Next, a second example (spunbond nonwoven fabric) of the method for producing the laminate 10 will be described.

[0118] The manufacturer prepares raw resin containing at least one type of thermoplastic resin. The nonwoven fabric manufacturing apparatus then heats and melts the raw resin in an extruder and continuously extrudes the raw resin in a fibrous form vertically downward from a spinneret connected to the extruder. The nonwoven fabric manufacturing apparatus then cools the extruded fibrous resin from the side with cold air while stretching it to a predetermined fiber diameter using a pulling device (ejector) to form thermoplastic fibers. The nonwoven fabric manufacturing apparatus then spreads and deposits the formed thermoplastic fibers on a net conveyor to form a web.

[0119] Here, when cooling the fibrous resin discharged from the spinneret with cold air, the nonwoven fabric manufacturing apparatus blows cold air containing at least one type of inorganic particles (inorganic particles coated with a coating material) onto the surface of the fibrous resin in addition to the normal cold air. This separate cold air is blown from the side at a position closer to the spinneret than normal, directly below the spinneret (e.g., 1 to 30 cm below the spinneret). This cold air is cold air with a higher flow rate or a lower temperature than normal. It is believed that this causes the formation of protrusions by the following mechanism (but is not limited to this): The separate cold air blows inorganic particles onto the surface of the unsolidified fibrous resin, positioning them and partially embedding them. As a result, protrusions made of inorganic particles are formed on the surface.

[0120] The nonwoven fabric manufacturing apparatus can also be used to manufacture meltblown nonwoven fabrics containing inorganic particles in the same manner as in the two examples above. The SMS nonwoven fabric (SMS layer) is formed by partially pressing the fibers of the manufactured spunbond nonwoven fabric, meltblown nonwoven fabric, and spunbond nonwoven fabric together using a pressing roll or the like provided in the nonwoven fabric manufacturing apparatus.

[0121] Next, the processing device uses the two produced SMS nonwoven fabrics, one as the skin-side sheet member and the other as the non-skin-side sheet member, to produce a laminate in which a plurality of elastic members are arranged at intervals in the direction (longitudinal direction) approximately perpendicular to the conveying direction and are held by fixing parts formed by heat fusion between the two sheet members. Heat fusion can be performed in two ways: by forming heat-sealed parts only by heating, or by forming heat-sealed parts using ultrasonic welding. The conditions for heat fusion using ultrasonic welding are as follows.

[0122] Heat fusion processing speed: 300 m / min Pressure: 500 N Fixation part creation pitch: 8 mm

[0123] [Second embodiment] The first embodiment described above is an embodiment of the laminate 10 in which a plurality of fixing portions 15 fix the elastic members 8 by heat fusion and a pair of opposing inner surfaces of the sheets are joined together, as shown in Fig. 3, but is not limited to this. For example, the fixing portions 15 may be formed with an adhesive, and in that case, the adhesive is selectively applied to the formation target positions on at least one of the pair of inner surfaces of the sheets where the fixing portions 15 are to be formed.

[0124] The second embodiment is an embodiment of a laminate 10 in which a plurality of fixing portions 15 directly fix the elastic members 8 by bonding using an adhesive or the like, and the inner surfaces of a pair of opposing sheets are joined together. The second embodiment is as described below. Note that a description of the same content as in the first embodiment will be omitted.

[0125] FIG. 12 is an external view of a region R, which is a portion of the laminate 10, when the multiple fixing portions 15 include multiple adhesive portions. When the fixing portions 15 include adhesive portions, for example, when the elastic members 8 are fixed by adhesive bonding, the fixing portions 15 are arranged as adhesive portions 16, which are areas where the adhesive is applied. The adhesive portions 16 are not limited to a specific shape, and known shapes and patterns (e.g., dot patterns, omega patterns, stripe patterns, spiral patterns) can be used. In this embodiment, the adhesive portions 16 are arranged in a rectangular shape that is long in the longitudinal direction L. The elastic members 8 are arranged perpendicular to the adhesive portions 16, i.e., along the stretching direction D. The adhesive portions 16 include a portion that directly fixes the elastic members 8 to the pair of inner surfaces of the sheets, and a portion that joins the pair of inner surfaces of the sheets together.

[0126] Since the multiple elastic members 8 are arranged at intervals in the longitudinal direction L, the adhesive portions 16 are also arranged at intervals in the longitudinal direction L. Note that the multiple adhesive portions 16 arranged in the longitudinal direction L do not overlap each other. The adhesive portions 16 are arranged at predetermined intervals in the stretching direction D. This is the seal pitch during manufacturing, and is, for example, 8 mm. When adhesion is performed without heat fusion, the thickness of the first sheet 11 and the second sheet 12 at the fixing portion 15 (adhesive portion 16) is approximately the same as that of other portions (not shown).

[0127] When forming an adhesive joint, if an adhesive (e.g., a hot melt adhesive) is applied to the surface of a fiber layer or sheet containing fibers with multiple protrusions, the adhesive or the like will penetrate into the voids and unevenness created by the protrusions. As a result, the surface of the fiber layer or sheet containing fibers with multiple protrusions exhibits an anchoring effect for the adhesive. Furthermore, fibers with multiple protrusions can make the fiber surface uneven, allowing for a larger surface area than fibers without protrusions. Therefore, fibers with multiple protrusions have a larger contact area with the adhesive or the like. Therefore, the surface of the fiber layer or sheet containing fibers with multiple protrusions can exhibit an anchoring effect for the adhesive or the like and can also increase the contact area.

[0128] When applying adhesive to the first sheet inner surface 11a (or the second sheet inner surface 12a) containing thermoplastic fibers, the amount of adhesive can be reduced to increase the flexibility of the laminate 10. Even if the adhesive film formed on the first sheet inner surface 11a (or the second sheet inner surface 12a) is thin, the anchoring effect of the thermoplastic fibers on the adhesive and the increased contact area can increase the bonding strength of the adhesive film to the thermoplastic fibers. This prevents the adhesive film from easily peeling off from the first sheet inner surface 11a (or the second sheet inner surface 12a). Therefore, the bonding strength of the first sheet inner surface 11a (or the second sheet inner surface 12a) to the other sheet inner surface and the fixing strength to the elastic member 8 can be increased.

[0129] Furthermore, since the amount of adhesive can be reduced, when the basis weight of the laminate 10 is reduced to further increase the flexibility of the laminate 10, the adhesive applied to the inner surface of one sheet during manufacturing can be prevented from seeping out from the inner surface of the other sheet. This can prevent problems from occurring during manufacturing, storage, and use. Furthermore, since the amount of adhesive can be reduced, not only can flexibility be improved, but the amount of organic material used can also be reduced, contributing to a reduction in the environmental impact.

[0130] As described above, in the laminate 10, when the fixing portion 15 functions as an adhesive bonded portion using an adhesive, the anchor effect of the adhesive or the like provided by the protrusions 21 of the thermoplastic fibers 20 increases the bonding strength of the adhesive portion when the elastic member 8 is directly fixed by the adhesive bonded portion, making it difficult for the elastic member 8 to peel off from the laminate 10. This makes it possible to prevent the elastic member 8 from shifting. Furthermore, even if the adhesive bonded portion peels off, the protrusions 21 come into contact with the elastic member 8, increasing frictional resistance, and preventing the elastic member 8 from shifting from the laminate 10.

[0131] Furthermore, in the regions where the first sheet inner surface 11a and the second sheet inner surface 12a contact the elastic member 8, the plurality of protrusions 21 (of the thermoplastic fibers 20) in the regions that are not in the adhesive region come into contact with the elastic member 8, increasing the frictional resistance of the elastic member 8. The increased frictional resistance makes it easier for the laminate 10 to fix the elastic member 8, and the laminate 10 can suppress slippage of the elastic member 8. Furthermore, since each of the plurality of protrusions 21 contains inorganic particles, the protrusions 21 can be formed stably.

[0132] The elastic members 8 in the back side portion 2 and the ventral side portion 3 extend along the stretching direction D, while the elastic members 8a in the leg gathered portions 5 and the elastic members 8b in the leakage barrier walls 7 extend along the longitudinal direction L. The elastic members 8a, 8b are fixed by adhesion using an adhesive or the like. Therefore, Figures 5 and 6 can be used to explain the laminate 10 in the case where adhesion is performed in the leg gathered portions 5 (or the leakage barrier walls 7) when the stretching direction D and the longitudinal direction L are interchanged and the elastic member 8 is replaced with the elastic member 8a (or 8b). The first sheet 11 and the second sheet 12 may be laminated by folding a single sheet with the elastic members 8 (8a, 8b) sandwiched between them.

[0133] Furthermore, the fixing portion 15 may include both a heat-sealed portion and a bonding portion. In this case, the first sheet 11 and the second sheet 12 can be bonded more strongly than when only either a heat-sealed portion or an adhesive portion is used. Also, displacement of the elastic member 8 can be further suppressed than when only either a heat-sealed portion or an adhesive portion is used.

[0134] [Third Embodiment] In the first and second embodiments described above, the laminate 10 is exemplified as having a configuration in which either the first sheet inner surface 11a or the second sheet inner surface 12a of a pair of opposing sheet inner surfaces includes thermoplastic fibers 20 having convex portions 21, but the configuration of the laminate 10 is not limited to this. In the third embodiment, the laminate 10 includes thermoplastic fibers 20 having convex portions 21 on both the first sheet inner surface 11a and the second sheet inner surface 12a. The third embodiment is as described below. Note that a description of the same content as in the first and second embodiments will be omitted.

[0135] In the third embodiment, in the laminate 10, both the first sheet inner surface 11a and the second sheet inner surface 12a contain thermoplastic fibers 20 having a plurality of protrusions 21. For example, as shown in FIG. 13 , a thermoplastic fiber layer 30 is provided on the first sheet inner surface layer and the second sheet inner surface layer. In the laminate, the frictional resistance generated in the elastic member 8 and the bonding strength between the elastic member 8 and the adhesive can be further increased compared to when the first sheet inner surface 11a or the second sheet inner surface 12a has a plurality of protrusions 21. This further reduces the slippage of the elastic member 8.

[0136] 13 is a cross-sectional view of a laminate 10 in which a first sheet 11 made of SMS nonwoven fabric and having a thermoplastic fiber layer 30 as an inner surface layer thereof is bonded to a second sheet 12 made of SMS nonwoven fabric and having a thermoplastic fiber layer 30 as an inner surface layer thereof, and an elastic member 8 is omitted from the illustration.

[0137] The laminate 10 of this embodiment includes the protrusions 21 containing inorganic particles on both the first sheet inner surface 11 a and the second sheet inner surface 12 a, and therefore can further increase the frictional resistance generated in the elastic member 8 and the bonding strength between the elastic member 8 and the adhesive, compared to when multiple protrusions 21 are provided on either the first sheet inner surface 11 a or the second sheet inner surface 12 a. This further reduces the slippage of the elastic member 8.

[0138] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0139] (1) Sheet Production [Production Example 1] Sheet No. 1 was obtained by the above production method. The conditions were as follows: Sheet inner surface layer: The fibers used were CaCO ３ 21.0 mass% of fiber and 79.0 mass% of polypropylene resin, and the basis weight is 5.5 g / m ２ The type is a spunbond layer. Sheet middle layer: 100.0 mass% polypropylene resin fiber, 2.0 g / m ２ , Meltblown layer sheet outer surface layer: Polypropylene resin 100.0 mass% fiber, 5.5 g / m ２ , spunbond layer

[0140] [Production Example 2] The outer surface layer of the sheet was made by changing "fiber of 100.0 mass% polypropylene resin" to "CaCO ３ Sheet No. 2 was obtained by the same production method as in Production Example 1, except that the fiber content was changed to "21.0 mass% of fiber and 79.0 mass% of polypropylene resin."

[0141] [Comparative Production Example 1] The inner surface layer of the sheet was ３ Sheet No. 3 was obtained by producing in the same manner as in Production Example 1, except that the "fibers containing 21.0 mass% of polypropylene resin and 79.0 mass% of polypropylene resin" was changed to "fibers containing 100.0 mass% of polypropylene resin."

[0142] When the sheets of Production Examples 1 and 2 and Comparative Example 1 are used as a first sheet, the sheet inner surface layer, sheet intermediate layer, and sheet outer surface layer become the first sheet inner surface layer, the first sheet intermediate layer, and the first sheet outer surface layer, respectively. When the produced sheets are used as a second sheet, the sheet inner surface layer, the sheet intermediate layer, and the sheet outer surface layer become the second sheet inner surface layer, the second sheet intermediate layer, and the second sheet outer surface layer, respectively.

[0143] Comparative Production Example 2 Pellet No. 1 was obtained from pellets containing 100.0% by mass of polypropylene resin.

[0144] [Comparative Production Example 3] CaCO ３ Pellet No. 2 was obtained from pellets containing 70.0% by mass of cellulose acetate and 30.0% by mass of polypropylene resin.

[0145] (2) Evaluation of the Produced Sheet [Example 1: Thermal Conductivity Measurement] CaCO ３ The thermal conductivity of Sheets No. 1 to No. 3 and Pellet No. 1 to No. 2 was measured using the well-known needle probe method to determine the rate of increase in thermal conductivity due to an increase in the ratio of . The results are shown in Table 1.

[0146]

[0147] CaCO ３ Sheet No. 1 and Sheet No. 2 contain CaCO ３ It was found that the thermal conductivity was higher at all temperatures than that of Sheet No. 3 and Pellet No. 1, which did not contain CaCO. ３ Pellet No. 2, which has 70% by mass of inorganic particles, has a higher thermal conductivity than Sheet No. 1 and Sheet No. 2, but cannot be manufactured into a nonwoven fabric or a laminate because the inorganic particles cause nozzle clogging in the nonwoven fabric manufacturing equipment that forms the fibers.

[0148] Each sheet and each pellet is made of CaCO ３ It can be seen that the higher the ratio of CaCO 2 in the sheet to be heat-sealed, the higher the thermal conductivity. ３ It is believed that the greater the proportion of , the higher the thermal fusion property.

[0149] Also CaCO ３ When the composition contained the compound, the thermal conductivity at 160°C was equal to or greater than the thermal conductivity at 230°C.

[0150] When comparing Sheet No. 3 and Pellet No. 1, there is no significant difference in thermal conductivity, so if the constituent components are the same, it is thought that the thermal conductivity is about the same. Therefore, based on the thermal conductivity results of Sheet No. 1 to No. 3 and Pellet No. 1 to Pellet No. 2 in Table 1, ３The estimation formulas for the change in thermal conductivity due to the change in concentration (mass%) were obtained. The estimation formulas are: Estimation Formula 1, which shows the thermal conductivity of the sample at 25°C; Estimation Formula 2, which shows the thermal conductivity of the sample at 160°C; and Estimation Formula 3, which shows the change in thermal conductivity of the sample at 230°C. Each estimation formula allows us to estimate the change in thermal conductivity of CaCO ３ Thermal conductivity when the concentration is 0 mass%, and CaCO ３ The thermal conductivity was calculated when the concentration was 21.0% by mass. The calculation results are shown in Table 2.

[0151]

[0152] CaCO at each target temperature calculated using estimation formulas 1 to 3 ３ Using the thermal conductivity at concentrations (mass%) of 0 mass% and 21.0 mass%, ３ The increase in thermal conductivity was calculated when the proportion of CaCO increased from 0% to 21.0%. The increase in thermal conductivity at 25°C was 1.23 times, the increase in thermal conductivity at 160°C was 1.21 times, and the increase in thermal conductivity at 230°C was 1.15 times. ３ When the concentration was 4.5 mass%, the estimated thermal conductivity was 0.191 W / (m·k). ３ It can be seen that the higher the concentration of , the greater the thermal conductivity at any temperature.

[0153] Therefore, the sheet members used in the laminate are made of CaCO ３ It can be seen that the inclusion of α-methyl-2-propanol improves the thermal conductivity, and the improvement is even greater at 160° C. It is believed that the improvement in thermal conductivity increases the area of ​​the heat-sealed portion of the laminate, thereby improving the heat-sealing properties.

[0154] (3) Production of Laminate [Example 1] Laminate No. 1 was produced by laminating the sheets produced in Production Examples 1 and 2 using the above production method. The conditions were as follows: First sheet: Sheet No. 1 Elastic member: polyurethane elastic fiber (fineness: 470 Dtex) Second sheet: Sheet No. 3

[0155] Example 2 Laminate No. 2 was obtained by the same production method as in Example 1, except that the second sheet was changed from Sheet No. 3 to Sheet No. 1.

[0156] Comparative Example 1 Laminate No. 3 was obtained by the same production method as in Example 1, except that the first sheet was changed from Sheet No. 1 to Sheet No. 3.

[0157] (4) Evaluation of Produced Laminates [Example 2: Determination of Rubber Loss in Elastic Members] The rubber loss (movement of the elastic member in the stretching direction) of Laminates Nos. 1 to 3 was determined by the following evaluation method. The results are shown in Table 3.

[0158] The evaluator performs the steps (1) to (5) to assess rubber deficiency. (1) The evaluator cuts out a sample from each laminate having four elastic members extending from one end to the other end in the 20 cm stretch direction. The longitudinal length of each laminate needs to be consistent, as long as the cut-outs have four elastic members. (2) The evaluator cuts the four elastic members between the fixing portions located in the center of the stretch direction. (3) The evaluator holds both ends of the laminate in the stretch direction from which the elastic members have been cut and manually stretches and contracts the laminate five times in the stretch direction. (4) The evaluator measures the gap distance between the elastic members in the laminate after stretching and contracting as the rubber deficiency distance. (5) The evaluator performs steps (1) to (4) above on 10 samples for each type of laminate and calculates the sum of the rubber deficiency distances (total rubber deficiency amount). (6) The evaluator determines that rubber deficiency has been suppressed if the total rubber deficiency amount is within 280 mm.

[0159]

[0160] When the total rubber loss is within 280 mm, the average rubber loss per elastic member in each laminate is within 7 mm. Therefore, in laminates No. 1 and No. 2, the rubber loss is shorter than the seal pitch of 8 mm, and it is considered that the elastic members cut in (2) above remain fixed to the fixing parts adjacent to the cut locations.

[0161] CaCO ３Laminate No. 3, which has a sheet inner surface that does not contain CaCO , has a fixing portion for fixing the elastic member, similar to Laminates No. 1 and No. 2, but a part of the cut elastic member may come out of the fixing portion. ３ In the laminates No. 1 and No. 2 having inner surfaces of sheets containing CaCO ３ It is believed that the formation of multiple protrusions increases the frictional resistance of the elastic member, making it difficult for the elastic member to move to a distant position.

[0162] That is, the laminate of the present invention is made of inorganic particles such as CaCO ３ It can be said that the inner surface of the sheet containing thermoplastic fibers having a plurality of protrusions formed by the above structure makes it easier to fix the elastic member by the fixing parts, and thus prevents the elastic member from slipping.

[0163] The laminate for absorbent articles and absorbent articles of the present invention are not limited to the above-mentioned embodiments and examples, and can be appropriately combined or modified, including with other technologies, within the scope that does not deviate from the purpose, intent, etc. of the present invention.

[0164] REFERENCE SIGNS LIST 1 disposable diaper 2 back portion 3 ventral portion 4 intermediate portion 5 leg gathered portion 6 absorbent body 6a absorber 7 leakage barrier 8 elastic member 8a elastic member 8b elastic member 9 elastic member group 9a elastic member group 9b elastic member group 9c elastic member group 9d elastic member group 10 laminate 11 first sheet 11a first sheet inner surface 12 second sheet 12a second sheet inner surface 15 fixed portion 16 opposed heat-sealed portion 20 thermoplastic fiber 21 convex portion 23 non-convex thermoplastic fiber CD stretching direction center line CL longitudinal direction center line D stretching direction L longitudinal direction LH leg opening R range SC side joining portion T １ Skin direction T ２ Non-skin facing WH Waist opening WP Waist area

Claims

1. A laminate for absorbent articles comprising a first sheet, a second sheet, and elastic members disposed between the first and second sheets and stretched in a stretching direction that does not intersect with the thickness direction of the first and second sheets, the laminate comprising a plurality of fixing parts that fix the elastic members to the first and second sheets along the stretching direction, the first and second sheets having a first sheet inner surface and a second sheet inner surface that are surfaces that come into contact with the elastic members, at least one of the first sheet inner surface and the second sheet inner surface comprising thermoplastic fibers having a plurality of protrusions, each of the plurality of protrusions comprising inorganic particles.

2. The laminate according to claim 1, wherein the plurality of fixing portions include at least one of a plurality of heat-sealed portions and a plurality of adhesive portions, the plurality of heat-sealed portions join the first sheet and the second sheet to each other by heat fusion and indirectly fix the elastic member, and the plurality of adhesive portions directly fix the elastic member to the inner surface of the first sheet and the inner surface of the second sheet.

3. The laminate according to claim 2, wherein both the inner surface of the first sheet and the inner surface of the second sheet contain the thermoplastic fibers having the plurality of protrusions.

4. The laminate described in claim 2 or 3, wherein the first sheet and the second sheet respectively have a first sheet outer surface and a second sheet outer surface which are opposite to the surface in contact with the elastic member, and when the first sheet inner surface contains the thermoplastic fiber having the plurality of protrusions, the mass proportion of the inorganic particles on the first sheet inner surface is higher than the mass proportion of the inorganic particles on the first sheet outer surface, and when the second sheet inner surface contains the thermoplastic fiber having the plurality of protrusions, the mass proportion of the inorganic particles on the second sheet inner surface is higher than the mass proportion of the inorganic particles on the second sheet outer surface.

5. The laminate according to claim 4, wherein at least one of the first sheet and the second sheet contains fine-diameter thermoplastic fibers having a smaller fiber diameter than the thermoplastic fibers and not containing the inorganic particles, and when the first sheet contains the fine-diameter thermoplastic fibers, the first sheet has a first-sheet intermediate layer containing the fine-diameter thermoplastic fibers between the inner surface and the outer surface of the first sheet, and when the second sheet contains the fine-diameter thermoplastic fibers, the second sheet has a second-sheet intermediate layer containing the fine-diameter thermoplastic fibers between the inner surface and the outer surface of the second sheet.

6. A laminate according to any one of claims 2 to 5, wherein the mass ratio of the inorganic particles in the thermoplastic fibers in at least one of the first sheet and the second sheet is 4.5% or more and 21.0% or less.

7. The laminate according to any one of claims 2 to 6, wherein the thermal conductivity of at least one of the first sheet and the second sheet at 160°C is 0.191 W / (m·k) or more and 0.224 W / (m·k) or less.

8. The laminate according to any one of claims 2 to 7, wherein the plurality of fixing portions include only the plurality of heat-sealed portions.

9. The laminate according to claim 8, wherein the plurality of heat-sealed portions include a plurality of pairs of opposing heat-sealed portions arranged opposite each other in a direction perpendicular to the stretching direction, the plurality of pairs of opposing heat-sealed portions being aligned at intervals in the stretching direction, and the pair of opposing heat-sealed portions gripping the elastic member.

10. An absorbent article comprising a laminate according to any one of claims 1 to 9.

11. The absorbent article according to claim 10, wherein the plurality of fixed portions include only a plurality of heat-sealed portions.

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